Processing liquid storage device, substrate processing device, and processing liquid supply method

Abstract

Providing technology that can ensure shutoff performance even in thin-walled tanks. [Solution] The processing liquid storage device 70 includes a storage tank 71 having a tank body 711 for storing processing liquid and a piping connection part 712 provided on the tank body 711; an outer shell 72 that covers the tank body 711 while leaving one end of the piping connection part 712 exposed and providing a gap space Vg between them; a first gas supply unit 73a that supplies a gas that does not contain the substance to be blocked to the internal space Vi of the tank body 711; a second gas supply unit 73b that supplies a gas that does not contain the substance to be blocked to the gap space Vg; and a control unit 75 that controls the amount of gas supplied to the internal space Vi so that the internal space Vi becomes positive pressure.

Description

Technical Field

[0001] The present disclosure relates to a processing liquid storage device, a substrate processing device, and a processing liquid supply method.

Background Art

[0002] In a substrate processing device used in a manufacturing process of a semiconductor device or the like, a substrate may be processed using a processing liquid. In many cases, the processing liquid is stored in a tank. The processing liquid stored in the tank is fed through a pipe connected to the tank, discharged from a nozzle or the like, and supplied to the substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] A tank for storing a processing liquid is required to have sufficient blocking performance. If the blocking performance is low, substances in the external atmosphere may permeate the tank and dissolve in the processing liquid stored therein. For example, if oxygen in the external atmosphere permeates the tank and dissolves in the processing liquid, the dissolved oxygen concentration of the processing liquid increases. As a result, an oxide film may be formed on the substrate (for example, a wiring pattern provided on the substrate) supplied with the processing liquid (and thus, the device characteristics may deteriorate).

[0005] The sealing performance of a tank increases with its wall thickness. However, in recent years, tanks have tended to be thinner. For example, conventional tanks were often formed by machining (i.e., a method of shaping the tank from a block of material using cutting equipment), but recently, tanks are increasingly being formed using mold molding (i.e., a method of shaping heated material using a mold). Mold molding makes it possible to reduce the roughness of the inner surface of the tank, which in turn suppresses the accumulation of particles on the inner surface and helps maintain a high level of cleanliness of the stored treatment liquid. However, with mold molding, it is difficult to increase the wall thickness of the tank compared to machining. In other words, when mold molding is adopted as a tank formation method to reduce the roughness of the inner surface of the tank, the tank wall thickness ends up being smaller. Also, fluororesins, which have excellent corrosion resistance, are often used as tank forming materials. However, fluororesins are a type of PFAS, and some fluororesins have a high environmental impact, and their use should be reduced. When tanks are formed using such fluororesins, the tank walls are made thinner to reduce the amount of forming material used. As the tank wall thickness decreases, it becomes more difficult to ensure the tank's sealing performance.

[0006] This disclosure aims to provide a technology that can ensure shutoff performance even in thin-walled tanks. [Means for solving the problem]

[0007] The first embodiment is a processing liquid storage device comprising: a storage tank having a tank body for storing processing liquid and a piping connection part provided on the tank body; an outer shell covering the tank body with a gap space between it and one end of the piping connection part exposed; a first gas supply unit for supplying a gas that does not contain the substance to be blocked to the internal space of the tank body; a second gas supply unit for supplying the gas that does not contain the substance to be blocked to the gap space; and a control unit for controlling the amount of gas supplied to the internal space so that the internal space becomes positive pressure.

[0008] A second embodiment is a processing liquid storage device according to the first embodiment, wherein the control unit controls the amount of gas supplied to the gap space so that the internal space and the gap space are at the same pressure.

[0009] A third embodiment is a processing liquid storage device according to the first or second embodiment, wherein the control unit increases the amount of gas supplied to the gap space when the amount of processing liquid flowing into the tank body is greater than the amount of processing liquid flowing out of the tank body.

[0010] A fourth embodiment is a processing liquid storage device according to any of the first to third embodiments, wherein the control unit reduces the amount of gas supplied to the gap space when the amount of processing liquid flowing out of the tank body is greater than the amount of processing liquid flowing into the tank body.

[0011] A fifth embodiment is a processing liquid storage device according to any of the first to fourth embodiments, wherein the control unit increases the amount of gas supplied to the internal space when the amount of processing liquid flowing out of the tank body is greater than the amount of processing liquid flowing into the tank body.

[0012] The sixth embodiment is a processing liquid storage device according to any of the first to fifth embodiments, comprising a labyrinth structure provided in the gap space.

[0013] The seventh embodiment is a substrate processing apparatus comprising a processing liquid storage device according to any of the first to sixth embodiments, a pipe connected to the pipe connection, and a nozzle connected to the pipe and supplying the processing liquid supplied through the pipe to a substrate.

[0014] The eighth aspect is a processing liquid supply method comprising: a first gas supply step of supplying a gas that does not contain the substance to be blocked into the internal space of a tank body that stores the processing liquid; and a second gas supply step of supplying the gas that does not contain the substance to be blocked into a gap space provided between the outer shell covering the tank body and the tank body, while exposing one end of a piping connection provided on the tank body, wherein in the first gas supply step, the amount of gas supplied to the internal space is controlled so that the internal space becomes positive pressure. [Effects of the Invention]

[0015] In the first embodiment, a gas that does not contain the substance to be blocked (the substance to be blocked) is supplied to the gap space provided between the tank body and the outer shell covering it. The amount of substance that permeates through the tank body and reaches its internal space (permeation rate) is proportional to the partial pressure (concentration) of the substance in the atmosphere surrounding the tank body. By supplying a gas that does not contain the substance to be blocked to the gap space, the partial pressure of the substance to be blocked in the atmosphere surrounding the tank body is kept low, and the amount of permeation of the substance to be blocked is kept low. Therefore, the blocking performance can be ensured even if the tank body is thin-walled. In addition, since the internal space of the tank body is under positive pressure, the intrusion of particles from the external space into the internal space can be suppressed.

[0016] According to the second embodiment, the differential pressure acting on the tank body is kept sufficiently small. Therefore, it is not necessary to give the tank body high strength, and it is permissible to reduce the wall thickness of the tank body.

[0017] According to the third embodiment, when the amount of treatment liquid flowing into the tank body is greater than the amount of treatment liquid flowing out of the tank body (i.e., when the liquid level of the treatment liquid rises in the internal space), the amount of gas supplied to the gap space is increased. Therefore, the pressure in the gap space increases in accordance with the increase in pressure in the internal space, and a large differential pressure is avoided in the tank body.

[0018] According to the fourth aspect, when the outflow rate of the processing liquid from the tank body is greater than the inflow rate of the processing liquid into the tank body (that is, when the liquid level of the processing liquid in the internal space decreases), the gas supply rate to the gap space is decreased. Therefore, the pressure in the gap space decreases following the decrease in the pressure in the internal space, and a large differential pressure is prevented from being applied to the tank body.

[0019] According to the fifth aspect, when the outflow rate of the processing liquid from the tank body is greater than the inflow rate of the processing liquid into the tank body (that is, when the liquid level of the processing liquid in the internal space decreases), the gas supply rate to the internal space is increased. Therefore, the decrease in the pressure in the internal space is suppressed.

[0020] According to the sixth aspect, the gas supplied to the gap space is difficult to escape from the gap space. Therefore, the gas consumption is difficult to increase.

[0021] According to the seventh aspect, since the blocking performance is ensured in the processing liquid storage device that stores the processing liquid supplied to the substrate, the dissolved concentration of the substance to be blocked in the processing liquid is difficult to increase. Therefore, it is difficult for a situation where the substance to be blocked has an adverse effect on the substrate to which the processing liquid is supplied to occur.

[0022] In the eighth aspect, a gas that does not contain the substance to be blocked is supplied to the gap space provided between the tank body and the outer shell that covers it. As a result, the partial pressure of the substance to be blocked in the atmosphere surrounding the tank body is suppressed to be low, and the permeation rate of the substance to be blocked is suppressed to be low. Therefore, even if the tank body is thin-walled, the blocking performance can be ensured. Further, since the internal space of the tank body is set to a positive pressure, it is possible to suppress the intrusion of particles from the external space into the internal space.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a plan view schematically showing a substrate processing apparatus. [Figure 2] FIG. 2 is a side view schematically showing a processing unit and a processing liquid supply unit. [Figure 3] Figure 3 is a block diagram showing the configuration of the control unit. [Figure 4] Figure 4 shows the flow of processing performed in the processing liquid supply section. [Figure 5] Figure 5 is a schematic side cross-sectional view showing the processing liquid storage device. [Figure 6] Figure 6 shows the processing flow related to the first gas supply process. [Figure 7] Figure 7 shows the processing flow related to the second gas supply process. [Figure 8] Figure 8 schematically illustrates the changes in gas supply rate and pressure at the stage when gas supply to the internal space and the gap space, respectively, is initiated. [Figure 9] Figure 9 schematically illustrates the changes in gas supply rate and pressure during the process of introducing unused processing liquid into the tank body. [Figure 10] Figure 10 schematically illustrates the changes in gas supply rate and pressure during the process in which a circulating state is formed. [Figure 11] Figure 11 schematically illustrates the changes in gas supply rate and pressure during the process in which the treatment liquid circulating in the circulation piping is supplied to the chemical nozzle. [Figure 12] Figure 12 schematically illustrates the changes in gas supply amount and pressure during the process of draining the treatment liquid stored in the tank body. [Figure 13] Figure 13 is a schematic side cross-sectional view showing a processing liquid storage device according to the first modified example. [Figure 14] Figure 14 is a schematic side cross-sectional view showing a processing liquid storage device according to the second modified example. [Figure 15] Figure 15 is a schematic side cross-sectional view showing a processing liquid storage device according to another modified example. [Modes for carrying out the invention]

[0024] The embodiments will be described below with reference to the attached drawings. Note that the components described in these embodiments are merely examples and are not intended to limit the scope of this disclosure to them alone. Furthermore, the drawings are schematic representations, and for the sake of clarity, some components may be omitted, dimensions may be exaggerated or simplified, numbers may be exaggerated or simplified, and components may be simplified as appropriate. Also, the positional relationships of the components shown in the drawings are not necessarily accurately represented.

[0025] Expressions indicating relative or absolute positional relationships (e.g., "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) shall, unless otherwise specified, not only strictly represent the positional relationship but also include states that are relatively displaced with respect to angle or distance, within a tolerance or range that yields equivalent functionality. Expressions indicating equality (e.g., "identical," "equal," "homogeneous," etc.) shall, unless otherwise specified, not only represent states that are quantitatively exactly equal but also include states where there are differences that yield tolerance or equivalent functionality. Expressions indicating shape (e.g., "circular," "elliptical," "quadrilateral," "cylindrical," etc.) shall, unless otherwise specified, not only strictly represent the shape geometrically but also include shapes within a range that yields equivalent functionality, such as having irregularities or chamfers. Expressions such as "equipped," "possessing," "containing," and "having" a component are not exclusive expressions that exclude the existence of other components. The expression "at least one of A, B, and C" includes "A only," "B only," "C only," "any two of A, B, and C," and "all of A, B, and C." When ordinal numbers such as "first" or "second" are used, these terms are used for convenience to facilitate understanding of the embodiments and are not limited to the order that may result from these ordinal numbers.

[0026] <1. Substrate Processing Equipment> <1-1. Structure> The configuration of the substrate processing apparatus 100 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic plan view of the substrate processing apparatus 100. Figure 2 is a schematic side view of the processing unit 4 and processing liquid supply unit 5 included in the substrate processing apparatus 100.

[0027] The substrate processing apparatus 100 includes a load port 1, an indexer robot 2, a main transport robot 3, a processing unit 4, a processing liquid supply unit 5, and a control unit 6.

[0028] (Load port 1) The load port 1 is an interface for loading and unloading substrates 9 into and from a storage container (e.g., carrier C) that houses multiple substrates 9. Multiple load ports 1 are provided, for example (three in the example shown in the figure). Multiple load ports 1 are arranged in a single row horizontally, for example. The carrier C may be a type that houses the substrates 9 in a sealed space (e.g., FOUP (Front Opening Unified Pod), SMIF (Standard Mechanical Interface) pod, etc.) or a type that exposes the substrates 9 to the outside air (e.g., OC (Open Cassette), etc.).

[0029] (Indexer Robot 2) The indexer robot 2 is a transport device that transports the substrate 9. For example, the indexer robot 2 is a horizontal articulated robot and is equipped with a pair of hands 21, 21 for holding the substrate 9 and arms 22 connected to each hand 21. The indexer robot 2 is also equipped with a drive mechanism (not shown) for rotating each hand 21 and bending, rotating, and raising and lowering each arm 22. The indexer robot 2 transports the substrate 9 between the carrier C placed on the load port 1 and the main transport robot 3. That is, the indexer robot 2 accesses the carrier C placed on the load port 1 and performs an unloading operation (i.e., the operation of taking out the substrate 9 contained in the carrier C with the hands 21) and an loading operation (i.e., the operation of placing the substrate 9 held by the hands 21 into the carrier C). The indexer robot 2 also accesses the transfer position and transfers the substrate 9 to and from the main transport robot 3.

[0030] (Main transport robot 3) The main transport robot 3 is a transport device that transports the substrate 9. For example, the main transport robot 3 is a horizontal articulated robot and is equipped with a pair of hands 31, 31 for holding the substrate 9 and arms 32 connected to each hand 31. The main transport robot 3 is also equipped with a drive mechanism (not shown) for rotating each hand 31 and bending, rotating, and raising and lowering each arm 32. The main transport robot 3 transports the substrate 9 between the indexer robot 2 and each processing unit 4. That is, the main transport robot 3 accesses the transfer position and transfers the substrate 9 to the indexer robot 2. The main transport robot 3 also accesses the processing unit 4 and performs loading operations (i.e., loading the substrate 9 held by the hands 31 into the processing unit 4) and unloading operations (i.e., unloading the substrate 9 from the processing unit 4 with the hands 31).

[0031] (Processing Unit 4) The processing unit 4 performs a predetermined process on the substrate 9 using a processing solution (e.g., a chemical solution and a rinsing solution). The processing unit 4 processes the substrate 9 one at a time (so-called single-wafer processing). Multiple processing units 4 may be provided in the substrate processing apparatus 100. In the example shown in the figure, multiple processing units 4 (e.g., 3) stacked vertically constitute one tower, and multiple such towers (4 in the example shown) are provided surrounding the main transport robot 3.

[0032] The processing unit 4 includes, for example, a spin chuck 41, a cup 42, a chemical nozzle 43, and a rinse nozzle 44. The spin chuck 41, cup 42, chemical nozzle 43, and rinse nozzle 44 are housed in the processing chamber 45.

[0033] The spin chuck 41 comprises a disc-shaped spin base 411, a holding part (not shown) above it that holds the substrate 9 in a horizontal position (a position in which the thickness direction of the substrate 9 is aligned with the vertical direction), and a drive mechanism (not shown) that rotates the spin base 411 around an axis (rotation axis) that extends vertically through the center of its main surface. With the substrate 9 held above the spin base 411, the spin base 411 rotates around the rotation axis, causing the substrate 9 to rotate around the rotation axis in a horizontal position.

[0034] Cup 42 receives the processing liquid discharged from the substrate 9, which is held and rotated by the spin chuck 41. Cup 42 is a cylindrical member and is positioned coaxially with the axis of rotation, surrounding the spin chuck 41. In the example shown, the upper part of cup 42 is shaped to narrow as it goes upward. A recovery pipe 421 is connected to cup 42 to collect the processing liquid received there. A lifting mechanism (not shown) is connected to cup 42, and driven by this lifting mechanism, cup 42 moves up and down between a processing position (for example, a position where the upper edge of cup 42 is positioned above the substrate 9 held by the spin chuck 41) and a retracted position (for example, a position where the upper edge of cup 42 is positioned below the spin base 411).

[0035] The chemical nozzle 43 supplies the chemical solution to the substrate 9 as the first processing solution. Specifically, the chemical nozzle 43 supplies the chemical solution to the substrate 9 by discharging the chemical solution toward the upper surface of the substrate 9 held by the spin chuck 41. The chemical nozzle 43 is connected to the processing solution supply unit 5 via a chemical pipe 432 in which a chemical valve 431 is inserted. When the chemical valve 431 is opened, the chemical solution supplied from the processing solution supply unit 5 is supplied to the chemical nozzle 43 through the chemical pipe 432 and discharged from the chemical nozzle 43. The chemical solution is, for example, hydrofluoric acid. However, the chemical solution is not limited to hydrofluoric acid, and may be, for example, a liquid containing at least one of sulfuric acid, acetic acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, ammonia water, hydrogen peroxide, organic acids (e.g., citric acid, oxalic acid, etc.), organic alkalis (e.g., TMAH: tetramethylammonium hydroxide, etc.), surfactants, and corrosion inhibitors.

[0036] The rinse liquid nozzle 44 supplies rinse liquid to the substrate 9 as a second processing liquid. Specifically, the rinse liquid nozzle 44 supplies rinse liquid to the substrate 9 by discharging the rinse liquid toward the upper surface of the substrate 9 held by the spin chuck 41. The rinse liquid nozzle 44 is connected to a rinse liquid supply source (not shown) via a rinse liquid pipe 442 in which a rinse liquid valve 441 is inserted. When the rinse liquid valve 441 is opened, the rinse liquid supplied from the rinse liquid supply source is supplied to the rinse liquid nozzle 44 through the rinse liquid pipe 442 and discharged from the rinse liquid nozzle 44. The rinse liquid is, for example, pure water (deionized water). However, the rinse liquid is not limited to pure water, and may be, for example, carbonated water, electrolyzed ionized water, hydrogen water, ozonated water, and hydrochloric acid water at a diluted concentration (for example, about 10 to 100 ppm).

[0037] (Processing liquid supply unit 5) The processing liquid supply unit 5 supplies processing liquid (here, chemical solution as the first processing liquid) to each processing unit 4. The processing liquid supply unit 5 is equipped with a processing liquid storage device 70 (which will be described in detail later). The processing liquid supply unit 5 is also equipped with a circulation pipe 51, a drain pipe 52, a recovery pipe 53, a new liquid pipe 54, and an overflow pipe 55. These pipes 51, 52, 53, 54, and 55 are connected to the processing liquid storage device 70 directly or indirectly. The processing liquid storage device 70 is housed in a cabinet (not shown), and the pipes 51, 52, 53, 54, and 55 connected to the processing liquid storage device 70 are brought out of the cabinet and connected to their respective destinations.

[0038] The circulation piping 51 is connected to the processing liquid storage device 70. For example, both ends of the circulation piping 51 are connected to the storage tank 71 (specifically, the piping connection part 712 provided on the tank body 711) (explained later). A pump 511 is provided on the circulation piping 51. The pump 511 pumps the processing liquid (in this case, chemical solution) stored in the storage tank 71 at the pressure necessary for circulation (circulation pressure). Therefore, when the pump 511 is operated, a state is created in which the processing liquid circulates in the circulation piping 51 (that is, the processing liquid stored in the storage tank 71 flows out of the storage tank 71, flows through the circulation piping 51 and flows back into the storage tank 71). In addition, the chemical solution piping 432 of each processing unit 4 (each of the multiple processing units 4 provided in the substrate processing device 100) is connected to the circulation piping 51. Therefore, when the chemical valve 431 inserted in the chemical pipe 432 is opened, a portion of the treatment liquid circulating in the circulation pipe 51 is supplied through the chemical pipe 432 to the chemical nozzle 43 connected thereto and discharged from there. It is also preferable that the circulation pipe 51 be provided with a filter 512. The filter 512 captures objects to be removed (e.g., particles, metals, etc.) contained in the treatment liquid flowing through the circulation pipe 51, thereby improving the cleanliness of the treatment liquid flowing through the circulation pipe 51. The air venting pipe 513 connected to the filter 512 may be connected, for example, to a storage tank 71 (specifically, a pipe connection part 712 provided in the tank body 711).

[0039] The drain pipe 52 is connected to the treated liquid storage device 70 via the circulation pipe 51. For example, one end of the drain pipe 52 is connected to the circulation pipe 51. The other end of the drain pipe 52 is connected to a drain line (not shown). The drain pipe 52 is provided with a drain valve 521. When the drain valve 521 is opened, the treated liquid stored in the storage tank 71 flows into the drain pipe 52 through the circulation pipe 51 and is guided to the drain line through the drain pipe 52.

[0040] The recovery piping 53 is connected to the processed liquid storage device 70. For example, one end of the recovery piping 53 is connected to the storage tank 71 (specifically, a piping connection part 712 provided on the tank body 711). The other end of the recovery piping 53 is connected to the recovery pipe 421 of each processing unit 4. A recovery valve 531 is provided on the recovery piping 53. When the recovery valve 531 is opened, the processed liquid (in this case, chemical solution) recovered in the cup 42 in the processing unit 4 flows into the recovery piping 53 through the recovery pipe 421 and into the storage tank 71 through the recovery piping 53. Although not shown in Figure 2, a drainage pipe may be provided that branches off from the recovery piping 53 and connects to a drainage line without going through the storage tank 71. In this case, the processed liquid recovered in the cup 42 can also be guided to the drainage line through the drainage pipe.

[0041] The new liquid pipe 54 is connected to the processing liquid storage device 70. For example, one end of the new liquid pipe 54 is connected to the storage tank 71 (specifically, to a pipe connection part 712 provided on the tank body 711). The other end of the new liquid pipe 54 is connected to the new liquid supply source 541. The new liquid supply source 541 stores unused processing liquid (in this case, unused chemical solution) (new liquid) that has never been supplied to the substrate 9. The new liquid pipe 54 is provided with a new liquid valve 542. When the new liquid valve 542 is opened, the unused processing liquid flows into the storage tank 71 through the new liquid pipe 54.

[0042] The overflow pipe 55 is connected to the processing liquid storage device 70. For example, one end of the overflow pipe 55 is connected to the storage tank 71 (specifically, a pipe connection part 712 provided on the tank body 711). The other end of the overflow pipe 55 is connected to, for example, a drain line. As an example, one end of the overflow pipe 55 is connected to a pipe connection part 712 provided at a height corresponding to the upper limit of the liquid level L. However, the "upper limit of the liquid level L" is the liquid level position when the storage tank 71 (specifically, the tank body 711) is filled with an amount of processing liquid equivalent to the tank capacity (i.e., the maximum amount of processing liquid that can be stored) (see Figure 5). In this case, if processing liquid exceeding the tank capacity flows into the storage tank 71, the excess processing liquid flows out of the storage tank 71 through the overflow pipe 55 and is guided to the drain line. This ensures that the amount of processed liquid stored in the storage tank 71 does not exceed the tank capacity (i.e., the liquid level of the processed liquid does not rise above the upper limit position L). When the liquid level of the processed liquid is below the upper limit position L, some of the gas in the storage tank 71 flows out of the storage tank 71 through the overflow pipe 55 and is guided to the drain line (exhausted).

[0043] (Control Unit 6) The control unit 6 controls the operation of each part of the substrate processing apparatus 100 (load port 1, indexer robot 2, main transport robot 3, processing unit 4, processing liquid supply unit 5, etc.). The control unit 6 is composed of, for example, a general-purpose computer with electrical circuits. As an example, as shown in Figure 3, the control unit 6 is composed of a CPU (Central Processor Unit) 61 as a central processing unit responsible for various arithmetic processing (data processing), a ROM (Read Only Memory) 62 in which basic programs are stored, a RAM (Random Access Memory) 63 used as a workspace when the CPU 61 performs predetermined processing (data processing), a storage device 64 (for example, a non-volatile storage device such as a flash memory or hard disk drive), and a bus line 65 connecting these to each other. The storage device 64 or RAM 63 may store a program P that defines the processing to be executed by the control unit 6. In this case, for example, the CPU 61 executes the program P, thereby controlling each part of the substrate processing apparatus 100, and the processing defined by the program P is executed in the substrate processing apparatus 100. In other words, the CPU 61 executes program P, and the control unit 6 may implement a circuit that performs the processing defined by program P. However, some or all of the control performed by the control unit 6 (some or all of the circuit implemented by the control unit 6) may be executed (implemented) by hardware such as dedicated logic circuits. Furthermore, program P may be stored on a recording medium, and program P may be installed in the control unit 6 using this recording medium.

[0044] <1-2. Processing Flow> <1-2-1. Overall Flow> The series of processes performed in the substrate processing apparatus 100 will now be described in general terms with reference to Figures 1 and 2. The series of processes performed in the substrate processing apparatus 100 proceed under the control of the control unit 6. That is, the control unit 6 controls each part of the substrate processing apparatus 100 (load port 1, indexer robot 2, main transport robot 3, processing unit 4 (specifically, spin chuck 41, cup 42 lifting mechanism, chemical solution valve 431, rinse solution valve 441, etc.), processing liquid supply unit 5, etc.), thereby enabling the series of processes to proceed in the substrate processing apparatus 100. Furthermore, the series of processes described below are repeated in the substrate processing apparatus 100.

[0045] First, the substrate 9 is loaded into the processing unit 4. Specifically, the indexer robot 2 accesses the carrier C placed on the load port 1, retrieves the unprocessed substrate 9 stored there, accesses the transfer position, and hands the substrate 9 to the main transport robot 3. Upon receiving the substrate 9 from the indexer robot 2, the main transport robot 3 accesses the processing unit 4 and loads the substrate 9 into the processing unit 4.

[0046] The substrate 9, once loaded into the processing unit 4, is held by the spin chuck 41. Specifically, the substrate 9 is held horizontally above the spin base 411. Once the substrate 9 is held, the spin base 411 begins to rotate. This causes the substrate 9, held by the spin chuck 41, to begin rotating.

[0047] Next, the chemical valve 431 is opened. Then, the chemical supplied from the processing liquid supply unit 5 is supplied to the chemical nozzle 43 through the chemical pipe 432 and discharged from there. As a result, the chemical is supplied to the substrate 9 (i.e., the substrate 9 held and rotated by the spin chuck 41), and the substrate 9 is treated with the chemical. For example, if hydrofluoric acid is used as the chemical, foreign matter such as particles is removed from the substrate 9 by the chemical. Here, before the supply of chemical to the substrate 9 begins, the cup 42 is moved from the retracted position to the processing position. Therefore, any chemical that has splashed around the substrate 9 is caught in the cup 42. The chemical that has been caught in the cup 42 is recovered through the recovery pipe 421. After a predetermined time has elapsed since the discharge of the chemical was started, the chemical valve 431 is closed.

[0048] Next, the rinse liquid valve 441 is opened. Then, the rinse liquid supplied from the rinse liquid supply source is supplied to the rinse liquid nozzle 44 through the rinse liquid piping 442 and discharged from there. As a result, the rinse liquid is supplied to the substrate 9 (i.e., the substrate 9 held and rotated by the spin chuck 41), and any chemicals adhering to the substrate 9 are washed away by the rinse liquid. While the rinse liquid is being supplied to the substrate 9, the cup 42 is positioned in the processing location, and any rinse liquid that splashes around the substrate 9 is caught in the cup 42. After a predetermined time has elapsed since the start of the discharge of the rinse liquid, the rinse liquid valve 441 is closed.

[0049] Next, the rotation speed of the spin base 411 is increased. As a result, the substrate 9 held in the spin chuck 41 rotates at high speed, and the rinse liquid adhering to the substrate 9 is swept away around the substrate 9 by centrifugal force (spin-drying). Even while the substrate 9 is rotating at high speed, the cup 42 is positioned in the processing location, and the rinse liquid scattered around the substrate 9 is caught in the cup 42. After the substrate 9 has rotated at high speed for a predetermined time, the rotation of the spin base 411 is stopped. As a result, the rotation of the substrate 9 held in the spin chuck 41 is stopped.

[0050] Subsequently, the substrate 9 is unloaded from the processing unit 4. Specifically, the main transport robot 3 unloads the processed substrate 9 from the processing unit 4, accesses the transfer position, and hands the substrate 9 to the indexer robot 2. Upon receiving the substrate 9 from the main transport robot 3, the indexer robot 2 places the substrate 9 into the carrier C located on the load port 1.

[0051] <1-2-2. Flow of processing carried out in the processing liquid supply section> Next, the series of processes performed in the processing liquid supply unit 5 will be explained with reference to Figure 4 in addition to Figure 2. Figure 4 is a diagram showing the flow of the series of processes performed in the processing liquid supply unit 5. Needless to say, the series of processes performed in the processing liquid supply unit 5 also proceed under the control of the control unit 6. That is, the control unit 6 controls each part of the processing liquid supply unit 5 (pump 511, drain valve 521, recovery valve 531, new liquid valve 542, etc.), thereby enabling the series of processes to proceed in the processing liquid supply unit 5.

[0052] First, unused treatment liquid (in this case, unused chemical solution) is introduced into an empty storage tank 71 that does not contain any treatment liquid (step S1). Specifically, a new liquid valve 542 located on the new liquid piping 54 is opened. As a result, the unused treatment liquid flows into the storage tank 71 through the new liquid piping 54 and is stored there.

[0053] Next, a state is formed in which the treatment liquid circulates through the circulation pipe 51 (circulation state) (step S2). Specifically, with the drain valve 521 and each chemical valve 431 closed, the pump 511 installed in the circulation pipe 51 is started to operate. As a result, the treatment liquid stored in the storage tank 71 begins to circulate through the circulation pipe 51.

[0054] Subsequently, at appropriate intervals, a portion of the processing liquid circulating in the circulation pipe 51 is supplied to the chemical nozzle 43 (step S3). Specifically, at appropriate intervals corresponding to the progress of processing in each processing unit 4, the chemical valve 431 provided in the chemical pipe 432 is opened. Then, a portion of the processing liquid circulating in the circulation pipe 51 is supplied through the chemical pipe 432 to the chemical nozzle 43 connected thereto and discharged from there. As a result, the chemical is supplied to the substrate 9, and the substrate 9 is processed by the chemical. In each processing unit 4, the substrate 9 is processed one after another, and the process in step S3 is repeated in synchronization with this.

[0055] Subsequently, at an appropriate timing (for example, when a predetermined lot of substrates 9 have been processed), the processing liquid stored in the storage tank 71 is drained (step S4). Specifically, the drain valve 521 provided in the drain pipe 52 is opened. Then, the processing liquid stored in the storage tank 71 flows into the drain pipe 52 through the circulation pipe 51, is guided to the drain line through the drain pipe 52, and is drained.

[0056] <2. Processing liquid storage device> <2-1. Structure> Next, the configuration of the processing liquid storage device 70 will be explained with reference to Figure 5. Figure 5 is a schematic side cross-sectional view showing the processing liquid storage device 70.

[0057] The processing liquid storage device 70 comprises a storage tank 71, an outer shell 72, a gas supply unit 73, a pressure measuring unit 74, and a control unit 75.

[0058] (Storage tank 71) The storage tank 71 comprises a tank body 711, a piping connection section 712, and a level pipe 713.

[0059] The tank body 711 is a container for storing the processing liquid used in processing the substrate 9. The tank body 711 is, for example, substantially rectangular parallelepiped in shape and comprises a flat bottom wall portion 711a, a peripheral wall portion 711b rising from the periphery of the bottom wall portion 711a, and a lid portion 711c that closes the opening on the upper end side of the peripheral wall portion 711b. The bottom wall portion 711a and the peripheral wall portion 711b, and the peripheral wall portion 711b and the lid portion 711c are all connected in an airtight and liquid-tight manner. As the forming material for the tank body 711, for example, fluororesin (e.g., PFA (perfluoroalkoxycan), PTFE (polytetrafluoroethylene)) can be used. Fluororesin is a material with excellent corrosion resistance and is suitable as the forming material for the tank body 711 that stores the chemical solution. The tank body 711 may be formed, for example, by mold molding (e.g., rotational molding).

[0060] The pipe connection section 712 is a joint for connecting pipes to the tank body 711, and one or more are provided on the tank body 711. The pipe connection section 712 is, for example, a cylindrical member with both ends open, and is provided so as to penetrate the bottom wall section 711a, the peripheral wall section 711b, or the lid section 711c, thereby connecting the inside and outside of the tank body 711 (internal space Vi and external space Vo) through the inside of the cylinder. The end of the pipe connection section 712 that is located outside the tank body 711 is the connection end 712a, to which the pipe is connected. Each pipe connection section 712 is connected to, for example, a circulation pipe 51, an air vent pipe 513, a recovery pipe 53, a new liquid pipe 54, an overflow pipe 55, a first gas supply pipe 732a (described later), etc.

[0061] The level pipe 713 is provided in the tank body 711. The level pipe 713 is, for example, an elongated cylindrical member with bent ends, and a scale (not shown) is provided along the direction of extension on the portion (scale portion) 713a that extends in a straight line. The level pipe 713 is positioned so that the direction of extension of the scale portion 713a is aligned with the vertical direction, and the portion (bent portion) 713b that bends and connects from both ends of the scale portion 713a is connected to the peripheral wall portion 711b of the tank body 711. The inside of the level pipe 713 is in communication with the internal space Vi of the tank body 711 through each end. Therefore, the processing liquid stored in the tank body 711 flows into the level pipe 713, and the liquid level in the level pipe 713 is equal to the liquid level of the processing liquid stored in the tank body 711. The operator can determine the level of the treated liquid stored in the tank body 711 (and thus the amount of treated liquid stored) by reading the liquid level of the level tube 713.

[0062] (Outer shell 72) The outer shell 72 encloses and covers the tank body 711, while providing a gap space Vg between them. In this embodiment, the outer shell 72 covers the entire tank body 711. For example, the outer shell 72 is a roughly rectangular parallelepiped, slightly larger than the tank body 711, and comprises a flat bottom wall portion 72a, a peripheral wall portion 72b rising from the periphery of the bottom wall portion 72a, and a lid portion 72c that closes the opening on the upper end side of the peripheral wall portion 72b. For example, by providing spacer members (not shown) at appropriate positions between the outer shell 72 and the tank body 711, gaps are provided between the bottom wall portion 72a and the bottom wall portion 711a, between the peripheral wall portion 72b and the peripheral wall portion 711b, and between the lid portion 72c and the lid portion 711c, and these gaps communicate with each other to form a gap space Vg. For example, stainless steel (SUS), polypropylene (PP), polyvinyl chloride (PVC), etc., can be used as the material for forming the outer shell 72.

[0063] The outer shell 72 is provided with an opening 721 at a position corresponding to the pipe connection portion 712 for insertion. When the pipe connection portion 712 is inserted through the opening 721, the connection end 712a is exposed to the outside of the outer shell 72. The outer shell 72 is also provided with openings 721 at positions corresponding to each bend 713b of the level pipe 713 for insertion. When each bend 713b is inserted through each opening 721, the scale portion 713a is exposed to the outside of the outer shell 72. Preferably, sealing members 722, such as O-rings, are provided in the gaps between the openings 721 and the pipe connection portion 712, and between the openings 721 and the bends 713b to airtightly seal these gaps.

[0064] (Gas supply section 73) The gas supply unit 73 comprises a first gas supply unit 73a and a second gas supply unit 73b.

[0065] a. First Gas Supply Unit 73a The first gas supply unit 73a supplies a predetermined gas to the internal space Vi of the tank body 711. The first gas supply unit 73a includes, for example, a first gas supply source 731a, a first gas supply pipe 732a, and a first flow rate adjustment valve 733a.

[0066] The first gas supply source 731a is a source of a predetermined gas. The predetermined gas supplied by the first gas supply source 731a is a gas that does not contain a substance to be blocked (a substance to be blocked). The substance to be blocked is a substance that is undesirable to dissolve in the processing liquid, such as oxygen. When the substance to be blocked is oxygen, an inert gas (for example, nitrogen gas, argon gas, helium gas, etc.) can be used as the predetermined gas.

[0067] The first gas supply pipe 732a is a pipe for sending gas supplied from the first gas supply source 731a to the internal space Vi. One end is connected to the first gas supply source 731a, and the other end is connected to the storage tank 71 (specifically, a pipe connection section 712 provided in the tank body 711). As an example, the other end of the first gas supply pipe 732a is connected to a pipe connection section 712 located at a position higher than the upper limit of the liquid level L. In this case, the gas supplied through the first gas supply pipe 732a is discharged into the gas phase space (the space above the liquid level of the processed liquid stored in the tank body 711).

[0068] The first flow rate control valve 733a is installed in the first gas supply pipe 732a. When the first flow rate control valve 733a is opened, a predetermined amount of gas flows from the first gas supply source 731a into the first gas supply pipe 732a and is supplied to the internal space Vi through the first gas supply pipe 732a. The flow rate of the gas flowing through the first gas supply pipe 732a (and thus the amount of gas supplied to the internal space Vi) is adjusted by the opening degree of the first flow rate control valve 733a, and the opening degree of the first flow rate control valve 733a is controlled by the control unit 75. In other words, the amount of gas supplied to the internal space Vi is controlled by the control unit 75.

[0069] b. Second gas supply section 73b The second gas supply unit 73b supplies a predetermined gas to the gap space Vg between the tank body 711 and the outer shell 72. The second gas supply unit 73b includes, for example, a second gas supply source 731b, a second gas supply pipe 732b, and a second flow rate adjustment valve 733b.

[0070] The second gas supply source 731b is a source of a predetermined gas. The predetermined gas supplied by the second gas supply source 731b is a gas that does not contain the substance to be blocked. As described above, the substance to be blocked is, for example, oxygen. When the substance to be blocked is oxygen, an inert gas (for example, nitrogen gas, argon gas, helium gas, etc.) can be used as the predetermined gas.

[0071] The second gas supply pipe 732b is a pipe for sending gas supplied from the second gas supply source 731b to the gap space Vg. One end is connected to the second gas supply source 731b, and the other end is connected to the outer shell 72 so as to face the gap space Vg.

[0072] The second flow rate control valve 733b is installed in the second gas supply pipe 732b. When the second flow rate control valve 733b is opened, a predetermined amount of gas flows from the second gas supply source 731b into the second gas supply pipe 732b and is supplied to the gap space Vg through the second gas supply pipe 732b. The flow rate of the gas flowing through the second gas supply pipe 732b (and therefore the amount of gas supplied to the gap space Vg) is adjusted by the opening degree of the second flow rate control valve 733b, and the opening degree of the second flow rate control valve 733b is controlled by the control unit 75. In other words, the amount of gas supplied to the gap space Vg is controlled by the control unit 75.

[0073] (Pressure measurement unit 74) The pressure measuring unit 74 includes a first pressure gauge 74a and a second pressure gauge 74b.

[0074] The first pressure gauge 74a measures the pressure in the internal space Vi. The measured value obtained by the first pressure gauge 74a is input to the control unit 75. Based on the measured value input from the first pressure gauge 74a, the control unit 75 controls the opening degree of the first flow control valve 733a (and consequently, the amount of gas supplied to the internal space Vi).

[0075] The second pressure gauge 74b measures the pressure in the gap space Vg. The measurement value obtained by the second pressure gauge 74b is input to the control unit 75. Based on the measurement value input from the first pressure gauge 74a and the measurement value input from the second pressure gauge 74b, the control unit 75 controls the opening degree of the second flow control valve 733b (and consequently, the amount of gas supplied to the gap space Vg).

[0076] (Control Unit 75) The control unit 75 controls the operation of each part of the processing liquid storage device 70 (first flow rate adjustment valve 733a, second flow rate adjustment valve 733b, etc.). The control unit 75 is composed of, for example, a general-purpose computer with electrical circuits. Some or all of the control performed by the control unit 75 may be implemented in the control unit 6 of the substrate processing device 100 (Figure 3). Alternatively, the control unit 75 may be controlled based on commands from the control unit 6 of the substrate processing device 100 to control the operation of each part of the processing liquid storage device 70.

[0077] <2-2. Processing Flow> a. First gas supply process In the processing liquid storage device 70, the first gas supply unit 73a supplies gas (a gas that does not contain the substance to be blocked) to the internal space Vi (first gas supply process). In the first gas supply process, the amount of gas supplied to the internal space Vi is controlled so that the internal space Vi becomes positive pressure. However, "positive pressure" is a pressure value higher than the pressure (hereinafter simply referred to as "external air pressure") Po of the external space Vo (the space outside the tank body 711 and the outer shell 72, for example, the internal space of the cabinet in which the processing liquid storage device 70 is housed).

[0078] The processing flow related to the first gas supply process will be explained in detail with reference to Figure 6. Figure 6 is a diagram showing the processing flow related to the first gas supply process.

[0079] First, the control unit 75 opens the first flow rate adjustment valve 733a. This starts the supply of gas to the internal space Vi (step S101). Here, the amount of gas supplied to the internal space Vi is controlled so that the internal space Vi reaches a predetermined pressure (reference pressure) Pt that is higher than the external pressure Po. For example, the control unit 75 supplies gas to the internal space Vi at a gas supply amount (first reference flow rate Q1) that brings the internal space Vi to the reference pressure Pt (see Figure 8). After a while, the amount of gas flowing into the internal space Vi and the amount of gas flowing out of the internal space Vi (for example, the amount of gas flowing out through the overflow pipe 55) both become almost constant, and the entire internal space Vi is filled with gas and reaches the reference pressure Pt.

[0080] After the first flow control valve 733a is opened, the control unit 75 acquires the measured pressure of the internal space Vi from the first pressure gauge 74a in real time (step S102).

[0081] Next, the control unit 75 determines whether or not the pressure in the internal space Vi has decreased (step S103). For example, the control unit 75 first calculates the difference between the measured pressure of the internal space Vi obtained in step S102 and the measured pressure of the internal space Vi obtained before that. If the calculated difference is negative (the pressure has decreased) and the absolute value of the calculated difference (the amount of pressure decrease) exceeds a predetermined allowable value, the control unit 75 determines that the pressure in the internal space Vi has decreased.

[0082] If the control unit 75 determines that the pressure in the internal space Vi has not decreased (NO in step S103), it does not change the amount of gas supplied to the internal space Vi (step S104).

[0083] On the other hand, if the control unit 75 determines that the pressure in the internal space Vi is decreasing (YES in step S103), it increases the amount of gas supplied to the internal space Vi (specifically, it increases the opening of the first flow rate control valve 733a) (step S105). This suppresses the decrease in the pressure in the internal space Vi. Therefore, the pressure in the internal space Vi does not drop significantly from the reference pressure Pt, and the internal space Vi is maintained at a positive pressure.

[0084] If, after the processing in step S104 or step S105, no instruction to stop the gas supply has arrived (NO in step S106), the processing in step S102 is performed again. In other words, the control unit 75 constantly monitors whether the pressure in the internal space Vi is decreasing until an instruction to stop the gas supply arrives, and if it determines that the pressure is decreasing (YES in step S103), it increases the amount of gas supplied to the internal space Vi (step S105). Therefore, until an instruction to stop the gas supply arrives, the pressure in the internal space Vi does not drop significantly from the reference pressure Pt, and the internal space Vi is maintained at a positive pressure.

[0085] When an instruction to stop the gas supply is received (YES in step S106), the control unit 75 closes the first flow rate adjustment valve 733a to stop the supply of gas to the internal space Vi (step S107).

[0086] The first gas supply process ensures that a gas free from the target substance is supplied to the internal space Vi of the tank body 711. Consequently, the partial pressure of the target substance in the internal space Vi is kept low, making it difficult for the dissolved concentration of the target substance in the processing liquid stored in the tank body 711 to increase. Furthermore, in the first gas supply process, the amount of gas supplied to the internal space Vi is controlled so that the internal space Vi is under positive pressure. Maintaining positive pressure in the internal space Vi suppresses the entry of particles from the external space Vo into the internal space Vi. Therefore, the cleanliness of the processing liquid stored in the tank body 711 is less likely to decrease.

[0087] b. Second gas supply process In the processing liquid storage device 70, the second gas supply unit 73b supplies gas (gas that does not contain the substance to be blocked) to the gap space Vg (second gas supply process). The second gas supply process is carried out in parallel with the first gas supply process. In the second gas supply process, the amount of gas supplied to the gap space Vg is controlled so that the internal space Vi and the gap space Vg have the same pressure. However, "the same pressure" in the two spaces here includes not only the case where the pressures of the two spaces are exactly the same, but also the case where the pressure difference between the two spaces is sufficiently small.

[0088] The processing flow related to the second gas supply process will be explained in detail with reference to Figure 7. Figure 7 is a diagram showing the processing flow related to the second gas supply process.

[0089] The control unit 75 opens the first flow rate control valve 733a and the second flow rate control valve 733b simultaneously. This starts the supply of gas to the internal space Vi and simultaneously starts the supply of gas to the gap space Vg (step S201). Here, the amount of gas supplied to the gap space Vg is controlled so that the gap space Vg reaches the same reference pressure Pt as the internal space Vi. For example, the control unit 75 starts supplying gas to the gap space Vg at a first reference flow rate Q1 and gradually decreases the gas supply amount from the first reference flow rate Q1 to the second reference flow rate Q2 (see Figure 8). When gas is supplied at the second reference flow rate Q2, the amount of gas flowing into the gap space Vg and the amount of gas flowing out of the gap space Vg are both approximately constant, and the entire gap space Vg is filled with gas to reach the reference pressure Pt.

[0090] After the second flow control valve 733b is opened, the control unit 75 acquires the measured pressure of the internal space Vi from the first pressure gauge 74a in real time, and also acquires the measured pressure of the gap space Vg from the second pressure gauge 74b in real time (step S202).

[0091] Next, the control unit 75 determines whether the internal space Vi and the gap space Vg are at the same pressure (step S203). For example, the control unit 75 first calculates the difference between the measured pressures of the internal space Vi and the gap space Vg obtained in step S202. Then, the control unit 75 determines that the internal space Vi and the gap space Vg are at the same pressure if the absolute value of the calculated difference is less than or equal to a predetermined allowable value, and determines that the internal space Vi and the gap space Vg are not at the same pressure if the absolute value of the calculated difference is greater than the predetermined allowable value.

[0092] If the control unit 75 determines that the internal space Vi and the gap space Vg are at the same pressure (YES in step S203), it does not change the amount of gas supplied to the gap space Vg (step S204).

[0093] On the other hand, if it is determined that the internal space Vi and the gap space Vg are not at the same pressure (NO in step S203), the control unit 75 changes the amount of gas supplied to the gap space Vg (step S205). Specifically, if the measured pressure of the gap space Vg obtained in step S202 is smaller than the measured pressure of the internal space Vi obtained in step S202, the control unit 75 increases the amount of gas supplied to the gap space Vg (specifically, it increases the opening of the second flow rate adjustment valve 733b). Conversely, if the measured pressure of the gap space Vg obtained in step S202 is larger than the measured pressure of the internal space Vi obtained in step S202, the control unit 75 decreases the amount of gas supplied to the gap space Vg (specifically, it decreases the opening of the second flow rate adjustment valve 733b). In other words, the control unit 75 changes the amount of gas supplied to the gap space Vg so that the pressure difference between the internal space Vi and the gap space Vg becomes smaller. This makes the pressure difference sufficiently small. In other words, the internal space Vi and the gap space Vg are under the same pressure.

[0094] If, after the processing in step S204 or step S205 has been completed, no instruction to stop the gas supply has been received (NO in step S206), the processing in step S202 is performed again. In other words, the control unit 75 constantly monitors whether the internal space Vi and the gap space Vg are at the same pressure until an instruction to stop the gas supply is received. If it determines that the pressures are not the same (NO in step S203), it changes the amount of gas supplied to the gap space Vg so that the pressure difference becomes smaller (so that the pressures are the same) (step S205).

[0095] When an instruction to stop the gas supply is received (YES in step S206), the control unit 75 closes the second flow rate adjustment valve 733b to stop the supply of gas to the gap space Vg (step S207).

[0096] The second gas supply process supplies a gas that does not contain the substance to be blocked into the gap space Vg between the tank body 711 and the outer shell 72. The amount of substance that permeates through the tank body 711 and reaches the internal space Vi (permeation rate) is proportional to the partial pressure (concentration) of the substance in the atmosphere surrounding the tank body 711. By supplying a gas that does not contain the substance to be blocked into the gap space Vg, the partial pressure of the substance to be blocked in the atmosphere surrounding the tank body 711 is kept low, and the amount of permeation of the substance to be blocked is kept low. Therefore, the blocking performance can be ensured even if the tank body 711 is thin-walled. By ensuring the blocking performance, an increase in the dissolved concentration of the substance to be blocked in the processing liquid stored in the tank body 711 is suppressed. In addition, in the second gas supply process, the amount of gas supplied to the gap space Vg is controlled so that the internal space Vi and the gap space Vg are at the same pressure. The pressure in the internal space Vi is the pressure pushing the tank body 711 from the inside to the outside, and the pressure in the gap space Vg is the pressure pushing the tank body 711 from the outside to the inside. Therefore, by making the gap space Vg and the internal space Vi the same pressure, the differential pressure on the tank body 711 is kept sufficiently small. For this reason, it is not necessary to give the tank body 711 high strength, and it is permissible to reduce the wall thickness of the tank body 711. In particular, when the internal space Vi of the tank body 711 is under positive pressure, normally the tank body 711 would have to have particularly high strength to withstand the increase in internal pressure, but this is not necessary here. In other words, even a tank body 711 with a small wall thickness can be allowed to have a positive pressure in its internal space Vi. Note that the tank body 711 is subjected to pressure (hydraulic pressure) from the liquid stored therein. However, in most cases, the hydraulic pressure is sufficiently small compared to the pressure from the gas supplied to the internal space Vi, so it can be ignored.

[0097] <2-3. Relationship with the processing performed in the processing liquid supply unit 5> The first and second gas supply processes are carried out in parallel with the series of processes in the processing liquid supply unit 5 (Figure 4). Here, we will explain how the gas supply amount and pressure change in each process performed in the processing liquid supply unit 5, referring to Figures 8 to 12. Each of Figures 8 to 12 schematically shows the state of the processing liquid supply unit 5 in each process, and schematically illustrates the change in the gas supply amount to the internal space Vi (black triangle), the change in the gas supply amount to the gap space Vg (white triangle), the change in the pressure in the internal space Vi (black circle), the change in the pressure in the gap space Vg (white circle), and the amount of processing liquid returned from the circulation piping 51 (white square). Note that in Figures 8 to 12, the pressure is shown as the differential pressure with respect to the ambient pressure Po.

[0098] a. The stage when gas supply is started. The series of processes in the processing liquid supply unit 5 (Figure 4) begin after the internal space Vi of the tank body 711 reaches the reference pressure Pt. In other words, prior to the start of the series of processes in the processing liquid supply unit 5, the supply of gas to the internal space Vi and the gap space Vg is started. Figure 8 schematically illustrates the changes in gas supply amount and pressure at this stage.

[0099] As described above, the control unit 75 supplies gas to the internal space Vi at a gas supply rate (first reference flow rate Q1) such that the internal space Vi becomes the reference pressure Pt. As a result, the entire internal space Vi is filled with gas and reaches the reference pressure Pt. In other words, the internal space Vi becomes positive pressure. The control unit 75 also starts supplying gas to the gap space Vg at the first reference flow rate Q1 and gradually decreases the gas supply rate from the first reference flow rate Q1 to the second reference flow rate Q2. As a result, the entire gap space Vg is filled with gas and reaches the reference pressure Pt. In other words, the internal space Vi and the gap space Vg become the same pressure. After this state is formed, a series of processes are started in the processing liquid supply unit 5.

[0100] b. Process in which the processing liquid is introduced. Figure 9 schematically illustrates the changes in gas supply amount and pressure during the process (step S1) in which unused processing liquid is introduced into an empty storage tank 71 (specifically, the tank body 711).

[0101] When the treatment liquid is introduced into the tank body 711, the amount of treatment liquid flowing into the tank body 711 (the amount of treatment liquid flowing in through the new liquid piping 54) is greater than the amount of treatment liquid flowing out of the tank body 711 (which is zero in this case). As a result, the liquid level of the treatment liquid rises in the internal space Vi. Consequently, the volume of the gas phase space in the internal space Vi decreases, and the pressure in the internal space Vi increases.

[0102] As the pressure in the internal space Vi increases, the pressure difference with the gap space Vg increases. As described above, the control unit 75 monitors whether the internal space Vi and the gap space Vg are at the same pressure, and if it determines that they are not at the same pressure (NO in step S203), it changes the amount of gas supplied to the gap space Vg so that the pressure difference decreases (step S205). Here, since the pressure difference is large due to the increase in the pressure in the internal space Vi, the control unit 75 increases the amount of gas supplied to the gap space Vg in order to reduce the pressure difference. As a result, the pressure in the gap space Vg increases in accordance with the increase in the pressure in the internal space Vi, and the pressure difference becomes sufficiently small. That is, the internal space Vi and the gap space Vg become at the same pressure. This prevents a large differential pressure from being applied to the tank body 711.

[0103] c. Process in which a circulating state is formed. Figure 10 schematically illustrates the changes in gas supply rate and pressure during the process (step S2) in which a circulating state is formed.

[0104] It takes some time from the start of operation of pump 511 until the entire circulation pipe 51 is filled with the processing liquid. During this time, the outflow rate of processing liquid from the tank body 711 (the amount of processing liquid supplied from one end of the circulation pipe 51) is greater than the inflow rate of processing liquid into the tank body 711 (the amount of processing liquid returning from the other end of the circulation pipe 51). As a result, the liquid level of the processing liquid in the internal space Vi drops. Consequently, the volume of the gas phase space in the internal space Vi increases, and the pressure in the internal space Vi decreases.

[0105] When the pressure in the internal space Vi decreases, the pressure difference with the gap space Vg increases. As described above, the control unit 75 monitors whether the internal space Vi and the gap space Vg are at the same pressure, and if it determines that they are not at the same pressure (NO in step S203), it changes the amount of gas supplied to the gap space Vg so that the pressure difference decreases (step S205). Here, since the pressure difference has increased due to the decrease in the pressure in the internal space Vi, the control unit 75 reduces the amount of gas supplied to the gap space Vg in order to reduce the pressure difference. As a result, the pressure in the gap space Vg decreases in accordance with the decrease in the pressure in the internal space Vi, and the pressure difference becomes sufficiently small. That is, the internal space Vi and the gap space Vg become at the same pressure. This prevents a large differential pressure from being applied to the tank body 711.

[0106] Meanwhile, the control unit 75 monitors whether the pressure in the internal space Vi is decreasing, and if it determines that the pressure is decreasing (YES in step S103), it increases the amount of gas supplied to the internal space Vi (step S105). This suppresses the decrease in pressure in the internal space Vi. Therefore, the internal space Vi is maintained at positive pressure. Furthermore, if the pressure in the internal space Vi decreases, there is a risk that the outflow rate of the processed liquid from the tank body 711 will decrease, but by suppressing the decrease in pressure in the internal space Vi, the decrease in the outflow rate of the processed liquid is suppressed. As a result, a circulation state can be quickly established.

[0107] d. Step in which the processing solution is supplied to the chemical nozzle 43. Figure 11 schematically illustrates the changes in gas supply amount and pressure during the process (step S3) in which a portion of the treatment liquid circulating in the circulation pipe 51 is supplied to the chemical nozzle 43.

[0108] When a portion of the treatment liquid circulating in the circulation pipe 51 is supplied to the chemical nozzle 43, the amount of treatment liquid flowing into the tank body 711 (the amount of treatment liquid returning from the other end of the circulation pipe 51) becomes less than the amount of treatment liquid flowing out of the tank body 711 (the amount of treatment liquid being supplied from one end of the circulation pipe 51). As a result, the liquid level of the treatment liquid in the internal space Vi decreases. Consequently, the volume of the gas phase space in the internal space Vi increases, and the pressure in the internal space Vi decreases.

[0109] When the pressure in the internal space Vi decreases, the pressure difference with the gap space Vg increases. As described above, the control unit 75 monitors whether the internal space Vi and the gap space Vg are at the same pressure. If it determines that they are not at the same pressure (NO in step S203), it changes the amount of gas supplied to the gap space Vg (in this case, decreases it) so that the pressure difference decreases (step S205). As a result, the pressure in the gap space Vg decreases in accordance with the decrease in the pressure in the internal space Vi, and the pressure difference becomes sufficiently small. In other words, the internal space Vi and the gap space Vg become at the same pressure. This prevents a large differential pressure from being applied to the tank body 711.

[0110] Meanwhile, the control unit 75 monitors whether the pressure in the internal space Vi is decreasing, and if it determines that the pressure is decreasing (YES in step S103), it increases the amount of gas supplied to the internal space Vi (step S105). This suppresses the decrease in pressure in the internal space Vi. Therefore, the internal space Vi is maintained at positive pressure. In addition, the decrease in the outflow rate of the processing liquid is suppressed. As a result, a sufficient amount of processing liquid is sent to the circulation piping 51, and a sufficient discharge pressure is maintained at the chemical nozzle 43.

[0111] e. Process in which the processing liquid is drained. Figure 12 schematically illustrates the changes in gas supply amount and pressure during the process (step S4) in which the processed liquid stored in the storage tank 71 (specifically, the tank body 711) is drained.

[0112] When the treated liquid is discharged from the tank body 711, the outflow rate of the treated liquid from the tank body 711 (the outflow rate of the treated liquid from the drainage pipe 52) is greater than the inflow rate of the treated liquid into the tank body 711 (which is zero in this case). As a result, the liquid level of the treated liquid in the internal space Vi decreases. Consequently, the volume of the gas phase space in the internal space Vi increases, and the pressure in the internal space Vi decreases.

[0113] When the pressure in the internal space Vi decreases, the pressure difference with the gap space Vg increases. As described above, the control unit 75 monitors whether the internal space Vi and the gap space Vg are at the same pressure. If it determines that they are not at the same pressure (NO in step S203), it changes the amount of gas supplied to the gap space Vg (in this case, decreases it) so that the pressure difference decreases (step S205). As a result, the pressure in the gap space Vg decreases in accordance with the decrease in the pressure in the internal space Vi, and the pressure difference becomes sufficiently small. In other words, the internal space Vi and the gap space Vg become at the same pressure. This prevents a large differential pressure from being applied to the tank body 711.

[0114] Meanwhile, the control unit 75 monitors whether the pressure in the internal space Vi is decreasing, and if it determines that the pressure is decreasing (YES in step S103), it increases the amount of gas supplied to the internal space Vi (step S105). This suppresses the decrease in pressure in the internal space Vi. Therefore, the internal space Vi is maintained at positive pressure. In addition, the decrease in the outflow rate of the processed liquid is suppressed. As a result, the processed liquid can be quickly drained from the tank body 711.

[0115] <3. Effects> The processing liquid storage device 70 according to the above embodiment comprises a storage tank 71, an outer shell 72, a first gas supply unit 73a, a second gas supply unit 73b, and a control unit 75. The storage tank 71 comprises a tank body 711 for storing the processing liquid and a piping connection unit 712 provided on the tank body 711. The outer shell 72 covers the tank body 711 while exposing one end of the piping connection unit 712, and leaving a gap space Vg between them. The first gas supply unit 73a supplies gas that does not contain the substance to be blocked to the internal space Vi of the tank body 711. The second gas supply unit 73b supplies gas that does not contain the substance to be blocked to the gap space Vg. The control unit 75 controls the amount of gas supplied to the internal space Vi so that the internal space Vi becomes positive pressure.

[0116] This configuration ensures barrier performance even if the tank body 711 is thin-walled. That is, as described above, the amount of a substance that permeates through the tank body 711 and reaches its internal space Vi (permeation rate) is proportional to the partial pressure of the substance in the atmosphere surrounding the tank body 711. By supplying a gas that does not contain the substance to be blocked into the gap space Vg, the partial pressure of the substance to be blocked in the atmosphere surrounding the tank body 711 is kept low, and the amount of permeation of the substance to be blocked is kept low. Therefore, barrier performance can be ensured even if the tank body 711 is thin-walled. Consequently, it is possible to suppress an increase in the dissolved concentration of the substance to be blocked in the processing liquid stored in the tank body 711. Here, since it is not necessary to increase the wall thickness of the tank body 711 to ensure barrier performance, it is permissible to reduce the wall thickness of the tank body 711. For example, barrier performance can be ensured even if the wall thickness of the tank body 711 is 5 mm or less (for example, 3 mm). By allowing a smaller wall thickness, it becomes possible to form the tank body 711 by mold molding. Consequently, it becomes possible to reduce the roughness of the inner surface of the tank body 711, thereby suppressing the accumulation of particles on the inner surface and maintaining a high level of cleanliness in the stored treatment liquid. Furthermore, by allowing a reduction in wall thickness, the amount of forming material used for the tank body 711 can be reduced. If the forming material is a substance with a high environmental impact, reducing its use can reduce the environmental impact.

[0117] Furthermore, according to the above configuration, a gas that does not contain the substance to be blocked is supplied to the internal space Vi of the tank body 711, and the control unit 75 controls the amount of gas supplied to the internal space Vi so that the internal space Vi is under positive pressure. By supplying a gas that does not contain the substance to be blocked to the internal space Vi, it is possible to suppress an increase in the dissolved concentration of the substance to be blocked in the processing liquid stored in the tank body 711. In addition, by maintaining positive pressure in the internal space Vi, it is possible to suppress the intrusion of particles from the external space Vo into the internal space Vi. Therefore, the cleanliness of the processing liquid stored in the tank body 711 can be kept at a high level.

[0118] Furthermore, in the above embodiment, the control unit 75 controls the amount of gas supplied to the gap space Vg so that the internal space Vi and the gap space Vg are at the same pressure. Therefore, the differential pressure on the tank body 711 is kept sufficiently small. For this reason, it is not necessary to give the tank body 711 high strength, and it is permissible to reduce the wall thickness of the tank body 711. As an example, it is permissible to make the wall thickness of the tank body 711 5 mm or less (for example, 3 mm).

[0119] Furthermore, in the above embodiment, the control unit 75 controls the amount of gas supplied to the internal space Vi so that the internal space Vi becomes positive pressure, and controls the amount of gas supplied to the gap space Vg so that the internal space Vi and the gap space Vg are at the same pressure. Therefore, not only the internal space Vi but also the gap space Vg becomes positive pressure. By making the gap space Vg positive pressure, the intrusion of the external atmosphere from the external space Vo into the gap space Vg is suppressed. Therefore, even if the external atmosphere contains the substance to be blocked, the partial pressure of the substance to be blocked in the gap space Vg is unlikely to rise.

[0120] Furthermore, in the above embodiment, the control unit 75 increases the amount of gas supplied to the gap space Vg when the amount of processing liquid flowing into the tank body 711 is greater than the amount of processing liquid flowing out of the tank body 711 (i.e., when the liquid level of the processing liquid rises in the internal space Vi). Therefore, the pressure in the gap space Vg increases in accordance with the increase in pressure in the internal space Vi, thus avoiding a large differential pressure being applied to the tank body 711.

[0121] Furthermore, in the above embodiment, the control unit 75 reduces the amount of gas supplied to the gap space Vg when the amount of processing liquid flowing out of the tank body 711 is greater than the amount of processing liquid flowing into the tank body 711 (i.e., when the liquid level of the processing liquid in the internal space Vi decreases). Therefore, the pressure in the gap space Vg decreases in accordance with the decrease in pressure in the internal space Vi, and a large differential pressure is avoided in the tank body 711.

[0122] Furthermore, in the above embodiment, the control unit 75 increases the amount of gas supplied to the internal space Vi when the amount of processing liquid flowing out of the tank body 711 is greater than the amount of processing liquid flowing into the tank body 711 (i.e., when the liquid level of the processing liquid in the internal space Vi decreases). Therefore, the decrease in pressure in the internal space Vi is suppressed.

[0123] Furthermore, the substrate processing apparatus 100 according to the above embodiment includes a processing liquid storage device 70, piping connected to a piping connection section 712 (for example, a piping section including a circulation pipe 51 and a chemical solution pipe 432 connected thereto), and a chemical solution nozzle 43 connected to the piping and supplying the processing liquid supplied through the piping to the substrate 9. With this configuration, since the blocking performance is ensured in the processing liquid storage device 70 that stores the processing liquid supplied to the substrate 9, the dissolved concentration of the substance to be blocked in the processing liquid is unlikely to increase. Therefore, it is unlikely that the substance to be blocked will adversely affect the substrate 9 to which the processing liquid is supplied. For example, if the substance to be blocked is oxygen, the dissolved oxygen concentration in the processing liquid is kept at a sufficiently low value, so it is unlikely that oxygen will adversely affect the substrate 9 to which the processing liquid is supplied (for example, an oxide film will be formed). Consequently, the device characteristics are less likely to deteriorate.

[0124] Furthermore, the processing liquid supply method according to the above embodiment includes a first gas supply step (Figure 6) in which a gas that does not contain the substance to be blocked is supplied to the internal space Vi of the tank body 711 that stores the processing liquid, and a second gas supply step (Figure 7) in which a gas that does not contain the substance to be blocked is supplied to the gap space Vg provided between the tank body 711 and the outer shell 72 that covers the tank body 711, while exposing one end of the piping connection portion 712 provided on the tank body 711. In the first gas supply step, the amount of gas supplied to the internal space Vi is controlled so that the internal space Vi becomes positive pressure. With this configuration, since a gas that does not contain the substance to be blocked is supplied to the gap space Vg provided between the tank body 711 and the outer shell 72 that covers it, the partial pressure of the substance to be blocked in the atmosphere surrounding the tank body 711 is kept low, and the amount of permeation of the substance to be blocked is kept low. Therefore, even if the tank body 711 is thin-walled, the blocking performance can be ensured. Furthermore, since the internal space Vi of the tank body 711 is under positive pressure, it is possible to suppress the entry of particles from the external space Vo into the internal space Vi.

[0125] <4. Variation> The configuration and operation of the processing liquid storage device 70 and the substrate processing device 100 according to the above embodiment can be modified as appropriate. In the following description, elements similar to those described in the above embodiment will be denoted by the same reference numerals, and their descriptions will be omitted.

[0126] <4-1. First variation> Figure 13 schematically shows a processing liquid storage device 70a according to the first modified example. The processing liquid storage device 70a differs from the processing liquid storage device 70 in that it includes a labyrinth structure 76. That is, the processing liquid storage device 70a includes a storage tank 71, an outer shell 72, a labyrinth structure 76, a gas supply unit 73, a pressure measuring unit 74, and a control unit 75. The configurations of the storage tank 71, outer shell 72, gas supply unit 73, pressure measuring unit 74, and control unit 75 are as described in the above embodiment.

[0127] The labyrinth structure 76 is provided in the gap space Vg. As an example, the labyrinth structure 76 is composed of one or more barriers (tank-side barriers) 761 erected on the outer surface of the tank body 711 and one or more barriers (outer shell-side barriers) 762 erected on the inner surface of the outer shell 72. The tank-side barrier 761 is, for example, an annular rib and is erected to surround the pipe connection portion 712 or the bend portion 713b. The outer shell-side barrier 762 is, for example, an annular rib and is erected to surround the opening 721 through which the pipe connection portion 712 is inserted, or the opening 721 through which the bend portion 713b is inserted. In the assembled state in which the outer shell 72 covers the tank body 711, the multiple barriers 761 and 762 are arranged concentrically in a nested manner. Also, in the assembled state, the tank-side barriers 761 and the outer shell-side barriers 762 are arranged alternately in the radial direction. Furthermore, in the assembled state, the protruding end of the tank-side barrier 761 is in close proximity to the inner surface of the outer shell 72 without contact, and the protruding end of the outer shell-side barrier 762 is in close proximity to the outer surface of the tank body 711 without contact. In other words, the placement position and dimensions of each barrier 761, 762 are defined so that such a positional relationship is formed in the assembled state.

[0128] In this modified configuration, the gas supplied to the gap space Vg by the second gas supply unit 73b successively strikes multiple barriers 761 and 762, resulting in pressure loss. As a result, the gas in the gap space Vg has difficulty escaping to the external space Vo through the opening 721. Therefore, even without airtight sealing between the tank body 711 and the outer shell 72 (for example, without sealing the gap between the pipe connection 712 or the bend 713b and the opening 721 with a sealing member 722, etc.), gas can be trapped in the gap space Vg and the pressure in the gap space Vg can be increased. In other words, even without providing a sealing member 722, etc., the amount of gas supplied (second reference flow rate Q2) required to maintain the gap space Vg at the reference pressure Pt can be kept small. That is, gas consumption is less likely to increase.

[0129] <4-2. Second variation> Figure 14 schematically shows a processing liquid storage device 70b according to a second modified example. The processing liquid storage device 70b differs from the processing liquid storage device 70 in that it has an outer shell 77 instead of an outer shell 72, and also has a coating layer 78. In other words, the processing liquid storage device 70b comprises a storage tank 71, an outer shell 77, a coating layer 78, a gas supply unit 73, a pressure measuring unit 74, and a control unit 75. The configurations of the storage tank 71, gas supply unit 73, pressure measuring unit 74, and control unit 75 are as described in the above embodiment.

[0130] The outer shell 77, like the outer shell 72 in the above embodiment, encloses and covers the tank body 711, while providing a gap space Vg between them. In this modified example, the outer shell 77 covers only a portion of the tank body 711. Specifically, the outer shell 77 covers the lower portion 711Q of the tank body 711. However, the "lower portion 711Q" refers to the portion of the tank body 711 below the upper limit liquid level position L. For example, the outer shell 77, when viewed from above, is a roughly rectangular parallelepiped that is slightly larger than the lower portion 711Q, and comprises a flat bottom wall portion 77a, a peripheral wall portion 77b rising from the periphery of the bottom wall portion 77a, and a canopy portion 77c protruding inward from an opening at the upper end of the peripheral wall portion 77b. For example, by providing spacer members (not shown) at appropriate positions between the outer shell 77 and the lower portion 711Q, gaps are created between the bottom wall portions 77a and 711a, and between the peripheral wall portions 77b and 711b, and these gaps communicate with each other to form a gap space Vg. On the other hand, the canopy portion 77c is airtightly connected to the peripheral wall portion 711b of the tank body 711 at its inner edge. This closes the upper end of the gap space Vg. Similar to the outer shell 72 in the above embodiment, for example, SUS (stainless steel), PP (polypropylene), PVC (polyvinyl chloride), etc. can be used as the forming material for the outer shell 77. Also, similar to the outer shell 72 in the above embodiment, the outer shell 77 is also provided with openings 771 for inserting pipe connection portions 712, etc., at positions corresponding to them. When pipe connection portions 712, etc. are inserted through the openings 771, the connection ends 712a, etc. are exposed to the outside of the outer shell 77.

[0131] The coating layer 78 covers at least the portion (exposed portion) 711R of the tank body 711 that is exposed from the outer shell 77. The coating layer 78 is provided in close contact with the exposed portion 711R without leaving any gap between it and the tank body 711. The method of forming the coating layer 78 can be anything. For example, the coating layer 78 may be formed by applying a coating solution (for example, a coating solution made by dissolving the forming material in a solvent) to the exposed portion 711R. Alternatively, the coating layer 78 may be formed by molding the forming material into a film and attaching the film to the exposed portion 711R using an adhesive or the like. Alternatively, the coating layer 78 may be integrally molded with the tank body 711 by a method such as two-color molding. It is preferable that the forming material of the coating layer 78 contains a component that does not easily allow the target substance to pass through (i.e., a component with sufficiently high blocking performance for the target substance). As an example, synthetic resins (for example, nylon, PVA (polyvinyl alcohol), etc.) can be used as the material for forming the coating layer 78.

[0132] According to this modification, by supplying a gas that does not contain the substance to be blocked into the gap space Vg, the partial pressure of the substance to be blocked in the atmosphere surrounding the lower portion 711Q of the tank body 711 is kept low, and the amount of permeation of the substance to be blocked in the lower portion 711Q is kept low. On the other hand, since a coating layer 78 is provided on the exposed portion 711R that is exposed from the outer shell 77 of the tank body 711, the amount of permeation of the substance to be blocked in the exposed portion 711R is also kept low. Therefore, even if the tank body 711 is thin-walled, the blocking performance can be ensured. The method of reducing the partial pressure of the surrounding substance to be blocked is more likely to keep the amount of permeation of the substance to be blocked low than the method of providing a coating layer 78. On the other hand, since the processing liquid is in direct contact with the inner surface of the lower portion 711Q, if a substance permeates through the lower portion 711Q, there is a high possibility that the substance will immediately dissolve in the processing liquid (i.e., it is highly likely to directly lead to an increase in dissolved concentration). Here, a method is applied to the lower portion 711Q to reduce the partial pressure of the surrounding target substance, thereby effectively suppressing an increase in the dissolved concentration of the target substance.

[0133] Furthermore, this modification allows for a reduction in the total number of openings 771 that need to be provided in the outer shell 77 compared to the case where the outer shell 77 covers the entire tank body 711. Generally, many of the piping connection parts 712 provided in the tank body 711 are located above the upper limit of the liquid level L (for example, on the lid 711c). Therefore, for example, by configuring the outer shell 77 so that it does not cover (exposes) the portion above the lower portion 711Q, the number of openings 771 that need to be provided in the outer shell 77 can be effectively reduced. Consequently, the structure of the outer shell 77 can be simplified, and it becomes easier to make the outer shell 77 airtight.

[0134] Furthermore, in this modified configuration, as in the above embodiment, the control unit 75 controls the amount of gas supplied to the gap space Vg so that the internal space Vi and the gap space Vg are at the same pressure. Therefore, the differential pressure on the lower portion 711Q is kept sufficiently small. In addition, the exposed portion 711R is reinforced by the provision of a covering layer 78 therein. For this reason, it is not necessary to give the tank body 711 high strength, and it is permissible to reduce the wall thickness of the tank body 711.

[0135] <4-3. Other variations> In the above embodiment, the first gas supply pipe 732a of the first gas supply unit 73a is connected to a pipe connection 712 located at a position higher than the upper limit of the liquid level L. However, the first gas supply pipe 732a may be connected to a pipe connection 712 located at or below the upper limit of the liquid level L. For example, as shown in Figure 15, the first gas supply pipe 732a may be connected to (or instead of) the pipe connection 712 located at a position higher than the upper limit of the liquid level L, to the bottom wall portion 711a of the tank body 711 or to a pipe connection 712 located sufficiently close to the bottom wall portion 711a. Furthermore, a nozzle (bubbling nozzle) 714 arranged along the bottom wall portion 711a may be connected to the other end of this pipe connection 712 (the side of the internal space Vi). In this case, at least a portion of the gas supplied through the first gas supply pipe 732a will be discharged into the liquid phase (the portion of the processed liquid stored in the tank body 711 below the liquid surface). By discharging gas that does not contain the substance to be blocked into the liquid phase, the partial pressure (dissolved concentration) of the substance to be blocked in the processed liquid can be reduced.

[0136] In the gas supply unit 73 according to the above embodiment, the gas supplied by the first gas supply unit 73a to the internal space Vi and the gas supplied by the second gas supply unit 73b to the gap space Vg may be the same type of gas or different types of gas. In the former case, the first gas supply unit 73a and the second gas supply unit 73b may share at least some elements. For example, the gas supply unit 73 includes one gas supply source and a branch pipe connected to the gas supply source at one end and branched at the other end, with one branch end of the branch pipe connected to the internal space Vi (specifically, the pipe connection part 712) and the other branch end connected to the gap space Vg (specifically, the outer shell 72). In this case, a flow rate adjustment valve may be provided downstream of the branching position in the branch pipe (i.e., at each branch section). Alternatively, a flow rate adjustment valve may be provided upstream of the branching position in the branch pipe, and a flow rate ratio adjustment unit may be provided at the branching position to adjust the ratio of the flow rates of the gas supplied to each branch section. If a flow rate ratio adjustment unit is provided at the branching point, gas will be supplied to both the internal space Vi and the gap space Vg at a flow rate ratio determined by the flow rate ratio adjustment unit. Alternatively, the system may be configured so that the same flow rate of gas is supplied to both the internal space Vi and the gap space Vg without providing a flow rate ratio adjustment unit at the branching point.

[0137] In the above embodiment, the configuration of the storage tank 71 can be modified as appropriate. For example, the shape of the tank body 711 does not necessarily have to be a rectangular parallelepiped. Also, the number of pipe connection parts 712 provided on the tank body 711 can be any number, and the arrangement (layout) of the pipe connection parts 712 can also be specified as appropriate. Furthermore, the level pipe 713 may be omitted.

[0138] In the first gas supply step according to the above embodiment, the control unit 75 increases the amount of gas supplied to the internal space Vi when it determines that the pressure in the internal space Vi is decreasing (YES in step S103). The amount of increase in the gas supply at this time may be a predetermined amount or an amount corresponding to the decrease in pressure.

[0139] In the second gas supply step according to the above embodiment, if the control unit 75 determines that the internal space Vi and the gap space Vg are not at the same pressure (NO in step S203), it changes the amount of gas supplied to the gap space Vg so that the pressure difference becomes smaller. The amount of change in the amount of gas supplied at this time may be a predetermined amount or an amount corresponding to the pressure difference.

[0140] In the first gas supply step according to the above embodiment, the control unit 75 may determine whether the pressure in the internal space Vi is rising, and if it determines that the pressure is rising, it may reduce the amount of gas supplied to the internal space Vi.

[0141] In the first modified example, the specific configuration of the labyrinth structure 76 can be changed as appropriate. Furthermore, the labyrinth structure 76 may be provided not only near the opening 721, but also at the boundary between the bottom wall portion 72a and the peripheral wall portion 72b, the boundary between the peripheral wall portion 72b and the lid portion 72c, etc. Alternatively, the labyrinth structure 76 may be provided throughout the entire gap space Vg.

[0142] In the second modified example, the outer shell 77 only needs to cover at least the lower portion 711Q, and may cover both the lower portion 711Q and the remaining portion. For example, the outer shell 77 may cover the portion below the lid portion 711c while leaving the lid portion 711c exposed. Also, the covering layer 78 only needs to cover at least the exposed portion 711R, and may further cover the unexposed portion (the portion covered by the outer shell 77) in addition to the exposed portion 711R. In other words, the tank body 711 may be partially covered by both the outer shell 77 and the covering layer 78.

[0143] The configuration and operation of the processing liquid supply unit 5 according to the above embodiment can be modified as appropriate. For example, although the processing liquid storage device 70 and the processing unit 4 are connected via a circulation pipe 51 and a chemical pipe 432, the circulation pipe 51 may be omitted. Also, the recovery pipe 53 connecting the processing liquid storage device 70 and the processing unit 4 may be omitted. In other words, the chemical used for processing in the processing unit 4 does not necessarily have to be recovered in the processing liquid storage device 70. Furthermore, various sensors (pressure sensors for detecting the pressure of the processing liquid flowing through the pipes, temperature sensors for detecting the temperature of the processing liquid flowing through the pipes, flow rate sensors for detecting the flow rate of the processing liquid flowing through the pipes, etc.) may be provided as needed in the various pipes of the processing liquid supply unit 5 (circulation pipe 51, drain pipe 52, recovery pipe 53, new liquid pipe 54, or overflow pipe 55).

[0144] The processing liquid storage device 70 according to the above embodiment may store various processing liquids used for processing the substrate 9. For example, the processing liquid storage device 70 may store a rinsing liquid used for processing the substrate 9. Needless to say, in this case, the processing liquid storage device 70 is connected to the rinsing liquid piping 442.

[0145] In the substrate processing apparatus 100 according to the embodiment, the substrate 9 to be processed may be, for example, a semiconductor substrate. Alternatively, the substrate 9 to be processed may be, for example, a photomask glass substrate, a liquid crystal display glass substrate, a plasma display glass substrate, a FED (Field Emission Display) substrate, an optical disc substrate, a magnetic disc substrate, a magneto-optical disc substrate, and the like. Furthermore, the substrate 9 to be processed may be circular or rectangular. Moreover, the substrate 9 to be processed does not have to be a perfect circle or a perfect rectangle, and may have notches, orientation flats, and other shaped portions.

[0146] The processing liquid storage device 70 may be mounted on various devices other than the substrate processing device 100 and used for storing the processing liquid used in said devices.

[0147] As described above, the processing liquid storage device, the substrate processing device, and the processing liquid supply method have been described in detail. However, the above descriptions are illustrative in all aspects, and the processing liquid storage device, the substrate processing device, and the processing liquid supply method are not limited thereby. Innumerable variations not illustrated can be conceived without departing from the scope of this disclosure. Each configuration described in each of the above embodiments and each of the above variations can be appropriately combined or omitted as long as they do not conflict with each other.

Explanation of Reference Numerals

[0148] 100 Substrate processing device 4 Processing unit 41 Spin chuck 42 Cup 43 Chemical liquid nozzle 44 Rinse liquid nozzle 45 Processing chamber 5 Processing liquid supply section 51 Circulation pipe 52 Drain pipe 53 Recovery pipe 54 Fresh liquid pipe 55 Overflow pipe 70, 70a, 70b Processing liquid storage device 71 Storage tank 711 Tank body 712 Pipe connection part 713 Level pipe 72, 77 Outer shell 721 Opening 722 Sealing member 73 Gas supply section 73a First gas supply section 731a First gas supply source 732a First gas supply pipe 733a First flow rate adjustment valve 73b Second gas supply section 731b Second gas supply source 732b Second gas supply pipe 733b Second flow rate adjustment valve 74 Pressure measurement unit 74a First pressure gauge 74b Second pressure gauge 75 Control unit 76 Labyrinth structure 78 Coating layer Vg Gap space Vi Internal space Vo External space

Claims

1. A storage tank comprising a tank body for storing processing liquid and a piping connection part provided on the tank body, An outer shell that covers the tank body while leaving a gap between it and one end of the aforementioned pipe connection, The first gas supply unit supplies a gas that does not contain the substance to be blocked into the internal space of the tank body, A second gas supply unit supplies a gas that does not contain the substance to be blocked into the gap space, A control unit controls the amount of gas supplied to the internal space so that the internal space becomes positively pressurized, A processing liquid storage device equipped with the following.

2. A processing liquid storage device according to claim 1, The control unit, The amount of gas supplied to the gap space is controlled so that the internal space and the gap space have the same pressure. Processing liquid storage device.

3. A processing liquid storage device according to claim 2, The control unit, When the amount of the processing liquid flowing into the tank body is greater than the amount of the processing liquid flowing out of the tank body, the amount of gas supplied to the gap space is increased. Processing liquid storage device.

4. A processing liquid storage device according to claim 2, The control unit, When the amount of the processing liquid flowing out of the tank body is greater than the amount of the processing liquid flowing into the tank body, the amount of gas supplied to the gap space is reduced. Processing liquid storage device.

5. A processing liquid storage device according to any one of claims 1 to 4, The control unit, When the amount of the processing liquid flowing out of the tank body is greater than the amount of the processing liquid flowing into the tank body, the amount of gas supplied to the internal space is increased. Processing liquid storage device.

6. A processing liquid storage device according to any one of claims 1 to 4, A labyrinth structure provided in the aforementioned gap space, A processing liquid storage device equipped with the following.

7. A processing liquid storage device according to any one of claims 1 to 4, The piping connected to the aforementioned pipe connection part, A nozzle connected to the aforementioned piping and supplying the processing liquid supplied through the piping to the substrate, A substrate processing apparatus comprising:

8. A first gas supply step involves supplying a gas that does not contain the substance to be blocked into the internal space of the tank body that stores the processing liquid, A second gas supply step involves supplying a gas that does not contain the substance to be blocked into a gap space provided between the outer shell covering the tank body and the tank body, while exposing one end of the piping connection portion provided on the tank body. Equipped with, In the first gas supply step, the amount of gas supplied to the internal space is controlled so that the internal space becomes positively pressurized. Method for supplying processing liquid.

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