Substrate processing device and substrate processing method

Abstract

To provide a technique for enhancing separation efficiency.SOLUTION: A first position Q1 and a second position are defined in a circulating pipe 62 connected to a recovery tank 60 that stores a mixed fluid containing water and organic solvents. The circulating pipe 62 includes: a first pipe portion 62a that connects a downstream side of the second position Q2 and an upstream side of the first position Q1; a second pipe portion 62b that connects the downstream side of the first position Q1 and the upstream side of the second position Q2; and a bypass pipe portion 62c that connects the downstream side of the first position Q1 and the upstream side of the second position Q2 through a path different from the second pipe portion 62b. A dehydrator 621 is provided on the first pipe portion 62a or the bypass pipe portion 62c. In a state where the mixed fluid is circulated in the first pipe portion 62a and the bypass pipe portion 62c, a pump 622 pressurizes the mixed fluid to separation pressure higher than circulating pressure necessary for circulation, and a heater 623 heats the mixed fluid up to predetermined heating temperature.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In substrate processing apparatuses used in the manufacturing process of semiconductor devices and the like, for example, a substrate is treated with a chemical solution and then rinsed with a rinse solution. In Patent Document 1, isopropyl alcohol (IPA) is supplied to the substrate (i.e., the substrate is covered with a rinse solution (typically water)) after rinsing with the rinse solution, and the rinse solution on the substrate is replaced with IPA. The substrate is then rotated at high speed to blow off the IPA adhering to the substrate, thereby drying the substrate. When rotating the substrate at high speed to blow off the adhering solution, there is a risk of the pattern collapsing due to the surface tension of the adhering solution. However, by previously replacing the water adhering to the substrate with IPA, which has a lower surface tension than the water, the pattern collapse is suppressed. Furthermore, because IPA is bipolar, it can evenly wet even hydrophobic substrate surfaces. This also reduces the likelihood of watermarks forming on the dried substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-41505 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 describes the recovery of IPA supplied to a substrate. Since IPA is supplied to a substrate covered with water, the recovered IPA is diluted with water (i.e., the IPA is recovered in the form of a mixed liquid containing water). Therefore, in order to reuse the recovered IPA, it is necessary to separate the water from the mixed liquid.

[0005] When separating water from a mixture of water and an organic solvent such as IPA, it is possible to use a separation membrane that allows water molecules to pass through but not organic solvent molecules. To shorten the time required for water separation, it is necessary to increase the separation efficiency of the separation membrane.

[0006] Therefore, an object of the present disclosure is to provide a technique that can improve the separation efficiency of a separation membrane. [Means for solving the problem]

[0007] A first aspect is a substrate processing apparatus comprising: a rinse liquid supply unit that supplies a rinse liquid containing water to a substrate; an organic solvent supply unit that supplies an organic solvent to the substrate; a recovery tank that stores a mixed fluid containing the water supplied to the substrate and then recovered; a circulation pipe connected to the recovery tank; a dehydrator provided in the circulation pipe and including a separation membrane that allows the water to pass but not the organic solvent; a pump provided in the circulation pipe; and a heater provided in the circulation pipe, wherein a first position and a second position are defined in the circulation pipe. The pipe comprises a first piping section connecting the downstream side of the second position with the upstream side of the first position, a second piping section connecting the downstream side of the first position with the upstream side of the second position, and a bypass piping section connecting the downstream side of the first position with the upstream side of the second position via a route different from that of the second piping section, the dehydrator is provided in the first piping section or the bypass piping section, and when the mixed fluid is circulating through the first piping section and the bypass piping section, the pump pressurizes the mixed fluid to a separation pressure higher than a circulation pressure required for circulation, and the heater heats the mixed fluid to a predetermined heating temperature.

[0008] A second aspect is the substrate processing apparatus according to the first aspect, wherein the recovery tank is provided in the second piping portion.

[0009] A third aspect is the substrate processing apparatus according to the first or second aspect, wherein the heating temperature is higher than the boiling point of the organic solvent under atmospheric pressure and lower than the boiling point of the organic solvent under the separating pressure.

[0010] A fourth aspect is the substrate processing apparatus according to the third aspect, wherein, in a state in which the mixed fluid is circulating through the first piping portion and the bypass piping portion, the pump pressurizes the mixed fluid to the separation pressure, and then the heater heats the mixed fluid to the heating temperature.

[0011] A fifth aspect is a substrate processing apparatus according to the third or fourth aspect, wherein, while a concentrated fluid obtained by separating the water from the mixed fluid is circulating through the first piping portion and the bypass piping portion, the heater stops heating, and after the temperature of the concentrated fluid becomes lower than the boiling point of the organic solvent under atmospheric pressure, the pump stops pressurizing the concentrated fluid.

[0012] A sixth aspect is a substrate processing apparatus according to any one of the first to fifth aspects, further comprising a vacuum pump that reduces the pressure in a space in the dehydrator on the side into which water that has passed through the separation membrane flows.

[0013] A seventh aspect is a substrate processing apparatus according to any one of the first to sixth aspects, comprising a purification tank connected to the recovery tank via the circulation piping and the liquid supply piping, for storing a concentrated fluid obtained by separating the water from the mixed fluid, and a filter provided in the piping connected to the purification tank, for capturing substances to be removed that are contained in the concentrated fluid flowing through the piping.

[0014] An eighth aspect is a substrate processing apparatus according to the seventh aspect, wherein the concentrated fluid stored in the purification tank is passed through the filter, then sent to the organic solvent supply section, and supplied to the substrate.

[0015] A ninth aspect is a substrate processing apparatus according to any one of the first to eighth aspects, wherein the circulation piping has a plurality of branching portions provided between a branching position downstream of the first position and a merging position upstream of the second position, and the recovery tank is provided in each of the plurality of branching portions.

[0016] A tenth aspect is a substrate processing apparatus according to any one of the first to ninth aspects, wherein the dehydrator is arranged in an orientation such that a cell that serves as a flow path for the mixed fluid within the separation membrane extends vertically, and the mixed fluid flowing through the circulation pipe flows in from an opening on the vertically lower side of the cell.

[0017] An eleventh aspect is the substrate processing apparatus according to any one of the first, second, and sixth to tenth aspects, wherein the heating temperature is equal to or higher than the boiling point of the water under the separating pressure.

[0018] A twelfth aspect is a substrate processing method including a rinse liquid supplying step of supplying a rinse liquid containing water to a substrate; an organic solvent supplying step of supplying an organic solvent to the substrate; a storing step of storing a mixed fluid containing the water supplied to the substrate and recovered therefrom and the organic solvent supplied to the substrate and recovered therefrom in a recovery tank; a filling step of filling a circulation pipe connected to the recovery tank with the mixed fluid stored in the recovery tank; a circulation step of circulating the mixed fluid through a first piping portion, a second piping portion, and a bypass piping portion of the circulation pipe; and a pressurizing step of pressurizing the mixed fluid circulating through the first piping portion and the bypass piping portion to a separation pressure higher than a circulation pressure required for circulation. The method includes a heating step of heating the mixed fluid circulating through the first piping portion and the bypass piping portion to a predetermined heating temperature, and a separation step of separating the water from the mixed fluid by causing the mixed fluid circulating through the first piping portion and the bypass piping portion to flow into a dehydrator equipped with a separation membrane that allows the water to pass through but not the organic solvent, wherein a first position and a second position are defined in the circulation piping, the first piping portion is a piping portion that connects the downstream side of the second position to the upstream side of the first position, the second piping portion is a piping portion that connects the downstream side of the first position to the upstream side of the second position, and the bypass piping portion is a piping portion that connects the downstream side of the first position to the upstream side of the second position via a route different from that of the second piping portion. [Effects of the Invention]

[0019] According to each of the first and twelfth aspects, the pressurized and heated mixed fluid can be caused to flow into the dehydrator, so that water can be efficiently separated from the mixed fluid.

[0020] According to the second aspect, since the recovery tank is provided in the second piping section, the pressurized and heated mixed fluid does not flow into the recovery tank, and therefore the recovery tank does not need to be pressure-resistant enough to withstand the separation pressure.

[0021] According to the third aspect, the temperature of the mixed fluid can be sufficiently increased without boiling the organic solvent, thereby ensuring safety and achieving high separation efficiency.

[0022] According to the fourth aspect, heating is carried out after the boiling point is increased by pressurization, so the organic solvent does not boil during heating.

[0023] According to the fifth aspect, the concentrated fluid is maintained in a pressurized state until the temperature is lowered to a temperature lower than the boiling point of the organic solvent under atmospheric pressure, so the organic solvent does not boil during the temperature drop.

[0024] According to the sixth aspect, separation of water can be promoted by reducing the pressure in the space in the dehydrator on the side into which the water that has passed through the separation membrane flows.

[0025] According to the seventh aspect, the substances to be removed can be removed from the concentrated fluid obtained by separating water from the mixed fluid, thereby increasing the purity of the concentrated fluid.

[0026] According to an eighth aspect, a concentrated fluid obtained by separating water from a mixed fluid containing water supplied to a substrate and then recovered and an organic solvent supplied to a substrate and then recovered is supplied to the substrate again after being purified, thereby reducing the amount of organic solvent used and discharged.

[0027] According to the ninth aspect, multiple recovery tanks are provided in the circulation pipe, and by switching the recovery tank to which the liquid is sent, the water that has been supplied to the substrate and then recovered and the organic solvent that has been supplied to the substrate and then recovered can be sent without interruption.

[0028] According to the tenth aspect, the mixed fluid flowing into the cell from the circulation pipe flows from bottom to top inside the cell extending in the vertical direction. Therefore, the mixed fluid flowing into the cell remains sufficiently inside the cell and comes into sufficient contact with the separation membrane. This further improves separation efficiency.

[0029] According to the eleventh aspect, the water contained in the mixed fluid can be made to flow into the dehydrator in a vapor state, thereby improving the separation efficiency at the separation membrane. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a plan view schematically showing an example of the configuration of a substrate processing apparatus. [Figure 2] FIG. 2 is a side view schematically illustrating an example of the configuration of a processing unit. [Figure 3] FIG. 2 is a diagram schematically illustrating a configuration example of an organic solvent recovery unit. [Figure 4] FIG. 2 is a side cross-sectional view schematically illustrating an example of the configuration of a dehydrator. [Figure 5] FIG. 3 is a diagram showing an example of a flow of processing performed in an organic solvent recovery section. [Figure 6] FIG. 1 is a diagram showing an example of a process flow for separating water from a mixed fluid. [Figure 7] FIG. 10 is a diagram for explaining step S1. [Figure 8] FIG. 10 is a diagram for explaining step S201. [Figure 9] FIG. 10 is a diagram for explaining step S202. [Figure 10] FIG. 10 is a diagram for explaining step S205. [Figure 11] FIG. 10 is a diagram for explaining step S207. [Figure 12] FIG. 10 is a diagram for explaining step S211. [Figure 13] FIG. 10 is a diagram for explaining step S212. [Figure 14] FIG. 10 is a diagram for explaining step S3. [Figure 15] FIG. 10 is a diagram for explaining step S4. [Figure 16] FIG. 10 is a diagram schematically illustrating a configuration example of an organic solvent recovery unit according to a modified example. [Figure 17] FIG. 10 is a diagram schematically illustrating a configuration example of an organic solvent recovery unit according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments will be described with reference to the accompanying drawings. Note that the components described in the embodiments are merely examples and are not intended to limit the scope of the present disclosure to only those components. Furthermore, the drawings are schematic, and for the sake of convenience of explanation, components may be omitted, dimensions may be exaggerated or simplified, the number of components may be exaggerated or simplified, and components may be simplified as appropriate. Furthermore, the positional relationships of the components shown in the drawings are not necessarily accurately depicted.

[0032] Expressions indicating relative or absolute positional relationships (e.g., "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) not only strictly represent the positional relationship but also include relative angular or distance displacements within a tolerance or equivalent functional range, unless otherwise specified. Expressions indicating an equal state (e.g., "identical," "equal," "homogeneous," etc.) not only represent quantitatively strict equality but also include differences within a tolerance or equivalent functional range, unless otherwise specified. Expressions indicating shape (e.g., "circular," "elliptical," "rectangular," "cylindrical," etc.) not only represent geometrically strict shapes but also include shapes within a range that achieves an equivalent effect, such as irregularities or chamfers, unless otherwise specified. Expressions such as "comprise," "include," "have," "include," and "have" of components are not exclusive expressions that exclude the presence 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 contents of the embodiments, and are not intended to limit the order that may result from these ordinal numbers.

[0033] <1. Substrate processing equipment> A substrate processing apparatus 100 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a plan view schematically showing an example of the configuration of the substrate processing apparatus 100.

[0034] The substrate processing apparatus 100 is a so-called single-wafer processing apparatus that processes substrates W to be processed one by one. The substrates W to be processed in the substrate processing apparatus 100 are, for example, semiconductor substrates. The shape of the substrates W to be processed is, for example, a disk shape.

[0035] The substrate processing apparatus 100 includes a load port 1, an indexer robot 2, a main transport robot 3, a processing unit 4, an organic solvent recovery unit 5, and a control unit 6.

[0036] The load port 1 is an interface for loading and unloading substrates W into and from a carrier C, which is a type of storage container that stores multiple substrates W. For example, multiple load ports 1 (three in the illustrated example) are provided. The multiple load ports 1 are arranged, for example, in a horizontal row. The carrier C may be of a type that stores substrates W in an enclosed space (for example, a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface) pod, etc.), or may be of a type that exposes substrates W to the outside air (for example, an OC (Open Cassette), etc.).

[0037] The indexer robot 2 is a transport device that transports substrates W. As an example, the indexer robot 2 is a horizontal articulated robot that includes a pair of hands 21, 21 that hold substrates W, and arms 22 connected to each hand 21. The indexer robot 2 also includes a drive mechanism (not shown) for rotating each hand 21 and bending and extending, rotating, and raising and lowering each arm 22. The indexer robot 2 transports substrates W between a 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 to perform an unloading operation (i.e., an operation of removing a substrate W accommodated in the carrier C with the hand 21) and a loading operation (i.e., an operation of placing a substrate W held by the hand 21 into the carrier C). The indexer robot 2 also accesses a transfer position to transfer substrates W to and from the main transport robot 3.

[0038] The main transport robot 3 is a transport device that transports substrates W. As an example, the main transport robot 3 is a horizontal articulated robot that includes a pair of hands 31, 31 that hold the substrates W, and an arm 32 connected to each hand 31. The main transport robot 3 also includes a drive mechanism (not shown) for rotating each hand 31 and bending and extending, rotating, and raising and lowering each arm 32. The main transport robot 3 transports substrates W between the indexer robot 2 and each processing unit 4. That is, the main transport robot 3 accesses a transfer position to transfer substrates W to and from the indexer robot 2. The main transport robot 3 also accesses a processing unit 4 to perform a load operation (i.e., an operation of loading the substrate W held by the hand 31 into the processing unit 4) and an unload operation (i.e., an operation of unloading the substrate W from the processing unit 4 with the hand 31).

[0039] The processing units 4 perform predetermined processing on the substrates W using processing liquids (e.g., chemical liquids, rinse liquids, and organic solvents). Here, for example, a plurality of (e.g., three) processing units 4 stacked vertically form a tower, and a plurality of such towers (four in the illustrated example) are provided so as to surround the main transport robot 3. The specific configuration of the processing units 4 will be described later.

[0040] The organic solvent recovery section 5 recovers the organic solvent used in the treatment in the treatment unit 4 and supplies it again to the treatment unit 4. Here, for example, the same number of organic solvent recovery sections 5 as the number of towers are provided. Each organic solvent recovery section 5 is associated one-to-one with each tower, and recovers the organic solvent used in the treatment in each treatment unit 4 included in the corresponding tower and supplies it again to each treatment unit 4. The specific configuration of the organic solvent recovery section 5 will be described later.

[0041] The control unit 6 controls the operation of each unit (load port 1, indexer robot 2, main transport robot 3, processing unit 4, and organic solvent recovery unit 5) included in the substrate processing apparatus 100. The control unit 6 is configured, for example, by a general computer having electrical circuits. As an example, the control unit 6 includes a CPU (Central Processor Unit) as a central processing unit that performs various arithmetic processing (data processing), a ROM (Read Only Memory) in which basic programs and the like are stored, a RAM (Random Access Memory) used as a work area when the CPU performs predetermined processing (data processing), a storage device (specifically, a nonvolatile storage device such as a flash memory or a hard disk drive), and a bus line connecting these components to each other. A program that defines the processing to be executed by the control unit 6 may be stored in the storage device or RAM. In this case, for example, the CPU may execute the program, thereby controlling each unit included in the substrate processing apparatus 100 via the control unit 6, and the processing defined by the program may be performed in the substrate processing apparatus 100. In other words, the CPU may execute the program, thereby realizing a circuit in the control unit 6 that performs the processing defined by the program. However, part or all of the control performed by the control unit 6 (part or all of the circuitry realized by the control unit 6) may be executed (realized) by hardware such as a dedicated logic circuit.

[0042] <2. Processing unit> <2-1. Processing unit configuration> The configuration of the processing unit 4 will be described with reference to Fig. 2. Fig. 2 is a side view schematically showing an example of the configuration of the processing unit 4.

[0043] The processing unit 4 performs a predetermined process using a processing liquid (e.g., a chemical liquid, a rinse liquid, and an organic solvent) on the substrate W. The processing unit 4 includes, for example, a spin chuck 41, a cup 42, and a nozzle 43. The spin chuck 41, the cup 42, and the nozzle 43 are housed in a processing chamber 44.

[0044] The spin chuck 41 holds the substrate W in a horizontal position (the thickness direction of the substrate W is aligned with the up-down direction (vertical direction)) and rotates the substrate W around an axis (rotation axis) A that passes through the center of its main surface and extends vertically. Specifically, the spin chuck 41 includes, for example, a spin base 411. The spin base 411 is a disk-shaped member and is positioned such that its thickness direction is aligned with the up-down direction. A plurality of chuck pins 412 are provided on the upper surface of the spin base 411. The plurality of chuck pins 412 are arranged at equal intervals along a circumference corresponding to the periphery of the substrate W. A link mechanism (not shown) that moves the plurality of chuck pins 412 between an abutment position and an release position is connected to the plurality of chuck pins 412. The "abutment position" is a position where the chuck pins 412 abut against the periphery of the substrate W. The "release position" is a position where the chuck pins 412 are spaced apart from the periphery of the substrate W. When each of the chuck pins 412 is positioned in the abutment position, the substrate W is held (chucked) in a horizontal position above the spin base 411. When each of the chuck pins 412 is positioned in the release position, the substrate W is released from its hold. The link mechanism switches the positions of the chuck pins 412 in response to instructions from the control unit 6. That is, the timing of holding the substrate W, the timing of releasing the substrate W, and the like are controlled by the control unit 6. The spin base 411 is connected to a spin motor 414 via a shaft unit 413 that is provided coaxially with the rotation axis A. The shaft unit 413 and the spin motor 414 are housed in a cover 415. The spin motor 414 rotates the shaft unit 413 about the rotation axis A. This causes the spin base 411, and ultimately the substrate W held above it, to rotate about the rotation axis A. The spin motor 414 rotates the spin base 411 in response to instructions from the control unit 6. That is, the controller 6 controls the rotation speed of the spin base 411 (and thus the substrate W), the timing at which the rotation starts, the timing at which the rotation ends, and the like.

[0045] The cup 42 receives the processing liquid discharged from the substrate W held and rotated by the spin chuck 41. Specifically, the cup 42 includes, for example, a cylindrical guide portion 421 arranged coaxially with the rotation axis A, an inclined portion 422 connected to the upper end of the guide portion 421 and tapering in diameter as it extends upward, and a liquid receiving portion 423 connected to the lower end of the guide portion 421 and forming an upwardly opening annular groove. A cup-side recovery pipe is provided in the liquid receiving portion 423 to recover the liquid received therein. Here, for example, a cup-side recovery pipe (not shown) for the chemical liquid and a cup-side recovery pipe 424 for the organic solvent are provided. A cup elevating mechanism 425 is connected to the cup 42 to raise and lower the cup 42 between a lower position and an upper position. The "lower position" is a position where the upper end of the cup 42 (specifically, the upper end of the inclined portion 422) is located below the substrate W held by the spin chuck 41. The "upper position" is a position where the upper end of the cup 42 is located above the substrate W held by the spin chuck 41. The cup lifting mechanism 425 lifts and lowers the cup 42 in response to an instruction from the control unit 6. That is, the position of the cup 42 is controlled by the control unit 6.

[0046] The nozzles 43 eject the processing liquid toward the upper surface of the substrate W held by the spin chuck 41. Here, for example, a separate nozzle 43 is provided for each type of processing liquid. That is, a nozzle 43 that ejects a chemical liquid (hereinafter also referred to as a "chemical liquid nozzle 43a"), a nozzle 43 that ejects a rinsing liquid (hereinafter also referred to as a "rinsing liquid nozzle 43b"), and a nozzle 43 that ejects an organic solvent (hereinafter also referred to as an "organic solvent nozzle 43c") are provided.

[0047] The chemical nozzle 43a discharges a chemical solution toward the upper surface of the substrate W held by the spin chuck 41. The chemical nozzle 43a is connected to a chemical solution supply source 433a via a chemical solution pipe 432a having a chemical solution valve 431a inserted therein. When the chemical solution valve 431a is opened, the chemical solution is supplied to the chemical solution nozzle 43a through the chemical solution pipe 432a, and the chemical solution is discharged from the chemical solution nozzle 43a. The chemical solution valve 431a is opened and closed in response to an instruction from the control unit 6. That is, the discharge timing of the chemical solution from the chemical solution nozzle 43a is controlled by the control unit 6. The chemical solution is, for example, hydrofluoric acid. However, the chemical solution is not limited to hydrofluoric acid, and may be a solution containing at least one of sulfuric acid, acetic acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, ammonia water, hydrogen peroxide water, organic acid (e.g., citric acid, oxalic acid, etc.), organic alkali (e.g., TMAH: tetramethylammonium hydroxide, etc.), surfactant, and corrosion inhibitor.

[0048] The rinse liquid nozzle 43b ejects the rinse liquid toward the upper surface of the substrate W held on the spin chuck 41. That is, here, the rinse liquid nozzle 43b serves as a rinse liquid supply unit that supplies the rinse liquid to the substrate W. The rinse liquid nozzle 43b is connected to a rinse liquid supply source 433b via a rinse liquid pipe 432b in which a rinse liquid valve 431b is interposed. When the rinse liquid valve 431b is opened, the rinse liquid is supplied to the rinse liquid nozzle 43b through the rinse liquid pipe 432b, and the rinse liquid is ejected from the rinse liquid nozzle 43b. The rinse liquid valve 431b is opened and closed in response to an instruction from the control unit 6. That is, the ejection timing of the rinse liquid from the rinse liquid nozzle 43b is controlled by the control unit 6. Here, the rinse liquid is assumed to be water (specifically, for example, pure water (deionized water)).

[0049] The organic solvent nozzle 43c ejects the organic solvent toward the upper surface of the substrate W held by the spin chuck 41. That is, the organic solvent nozzle 43c serves as an organic solvent supply unit that supplies the organic solvent to the substrate W. The organic solvent nozzle 43c is connected to the organic solvent recovery unit 5 via an organic solvent pipe 432c having an organic solvent valve 431c inserted therein. When the organic solvent valve 431c is opened, the organic solvent (an organic solvent with a sufficiently high purity, specifically, for example, an organic solvent with a purity of 99 wt % or more) is supplied to the organic solvent nozzle 43c through the organic solvent pipe 432c, and the organic solvent is ejected from the organic solvent nozzle 43c. The organic solvent valve 431c is opened and closed in response to an instruction from the control unit 6. That is, the ejection timing of the organic solvent from the organic solvent nozzle 43c is controlled by the control unit 6. The organic solvent is, for example, a water-soluble organic solvent. Here, the organic solvent is assumed to be isopropyl alcohol (IPA).

[0050] At least one of the chemical liquid nozzle 43a, the rinse liquid nozzle 43b, and the organic solvent nozzle 43c may be connected to a nozzle moving mechanism that moves the nozzle between a processing position and a retracted position. The "processing position" is a position where the processing liquid ejected from the nozzles 43a, 43b, and 43c is supplied to the substrate W held on the spin chuck 41. The "retracted position" is a position where the nozzles 43a, 43b, and 43c are located outside (radially outward from) the periphery of the substrate W held on the spin chuck 41 when viewed from above. In this case, the nozzle moving mechanism moves the nozzles 43a, 43b, and 43c in response to an instruction from the control unit 6. That is, the positions of the nozzles 43a, 43b, and 43c are controlled by the control unit 6.

[0051] <2-2. Operation of the processing unit> An example of the operation of the processing unit 4 will now be described with continued reference to FIG.

[0052] The operations performed in the processing unit 4 are performed under the control of the control unit 6. That is, the control unit 6 controls the chuck pin 412, the spin motor 414, the cup lifting mechanism 425, the chemical liquid valve 431a, the rinse liquid valve 431b, the organic solvent valve 431c, and the like, thereby causing a series of operations to proceed in the processing unit 4.

[0053] When the substrate W is carried into the processing chamber 44 by the main transport robot 3, the spin chuck 41 holds the substrate W. Then, the spin chuck 41 starts to rotate.

[0054] In this state, the chemical valve 431a is opened. Then, the chemical nozzle 43a discharges the chemical toward the upper surface of the substrate W, which is held and rotated by the spin chuck 41. This causes the chemical to be supplied to the entire upper surface of the substrate W, and the substrate W is treated with the chemical (chemical supplying step). For example, if hydrofluoric acid is used as the chemical, the chemical removes foreign matter such as particles from the substrate W. During the chemical supplying step, the cup 42 is positioned in the upper position. Therefore, the chemical that has splashed around the substrate W is received by the cup 42. Specifically, the chemical that has splashed around the substrate W is received by the inclined portion 422, guided downward by the guide portion 421, and collected in the liquid receiving portion 423. The chemical received by the cup 42 (i.e., the chemical collected in the liquid receiving portion 423) is collected through a cup-side recovery pipe for the chemical (not shown).

[0055] When a predetermined time has elapsed since the start of the discharge of the chemical liquid, the chemical liquid valve 431a is closed. This stops the discharge of the chemical liquid from the chemical liquid nozzle 43a. Subsequently, the rinse liquid valve 431b is opened. This causes the rinse liquid to be discharged from the rinse liquid nozzle 43b toward the upper surface of the substrate W, which is held and rotated by the spin chuck 41. As a result, the rinse liquid is supplied to the entire upper surface of the substrate W, and the chemical liquid adhering to the substrate W is washed away by the rinse liquid (rinse liquid supplying step). The cup 42 is also positioned in the upper position during the rinse liquid supplying step. Therefore, the chemical liquid and rinse liquid splashed around the substrate W are received by the cup 42. The chemical liquid and rinse liquid received by the cup 42 are collected through a cup-side recovery pipe for the chemical liquid (not shown).

[0056] When a predetermined time has elapsed since the discharge of the rinse liquid started, the rinse liquid valve 431b is closed. This stops the discharge of the rinse liquid from the rinse liquid nozzle 43b. Subsequently, the organic solvent valve 431c is opened. This causes IPA to be discharged from the organic solvent nozzle 43c toward the upper surface of the substrate W, which is held and rotated by the spin chuck 41. As a result, IPA is supplied to the entire upper surface of the substrate W, and the rinse liquid adhering to the substrate W is replaced with IPA (organic solvent supplying step). The cup 42 remains in the upper position even during the organic solvent supplying step. Therefore, the rinse liquid and IPA splashed around the substrate W are received by the cup 42. The rinse liquid and IPA received by the cup 42 are recovered through the cup-side recovery pipe 424 for organic solvent.

[0057] After a predetermined time has elapsed since the start of the IPA supply, the organic solvent valve 431c is closed. This stops the discharge of IPA from the organic solvent nozzle 43c. At this stage, the rinse liquid on the substrate W is completely replaced with IPA, and a liquid film of IPA is formed covering the entire upper surface of the substrate W. Next, the spin chuck 41 starts rotating at high speed. This causes the substrate W to rotate at high speed, and the IPA on the substrate W is scattered around the substrate W by centrifugal force (spin drying process). The cup 42 remains in the upper position while the substrate W is being rotated at high speed. Therefore, the IPA splashed around the substrate W is collected by the cup 42. The IPA collected by the cup 42 is collected through the cup-side recovery pipe 424 for organic solvent.

[0058] When a predetermined time has elapsed since the high-speed rotation of the spin chuck 41 began, the rotation of the spin chuck 41 is stopped. At this stage, the IPA has been removed from the substrate W, and the substrate W has been dried. The dried substrate W is then carried out of the processing chamber 44 by the main transport robot 3.

[0059] This completes the series of processes for one substrate W. In the processing unit 4, the series of operations described above is repeated to process the substrates W one by one.

[0060] <3. Organic solvent recovery section> <3-1. Structure> The configuration of the organic solvent recovery section 5 will be described with reference to Fig. 3. Fig. 3 is a diagram schematically showing an example of the configuration of the organic solvent recovery section 5.

[0061] The organic solvent recovery unit 5 includes a recovery tank 60, a purification tank 70, and a supply tank 80. As an example, the recovery tank 60 and the purification tank 70 are accommodated in a first storage box 50a, and the supply tank 80 is accommodated in a second storage box 50b. As an example, the first storage box 50a is disposed outside the outer wall 100a of the substrate processing apparatus 100 (for example, below (underground) the clean room in which the substrate processing apparatus 100 is installed), and the second storage box 50b is disposed inside the outer wall 100a of the substrate processing apparatus 100 (FIG. 1).

[0062] (a) Recovery tank 60 The recovery tank 60 is connected to the cup 42 via a recovery pipe 61. That is, one end of the recovery pipe 61 is connected to the recovery tank 60, and the other end of the recovery pipe 61 is connected to the cup 42 (specifically, the cup-side recovery pipe 424 connected to the cup 42). In this example, for example, the recovery pipe 61 is connected to the cups 42 of the processing units 4 that belong to the same tower. A recovery valve 611 is provided on the recovery pipe 61. When the recovery valve 611 is opened, the organic solvent (IPA in this case) collected in the cup 42 in the organic solvent supplying step and the spin drying step is guided through the recovery pipe 61 and flows into the recovery tank 60, where it is stored. However, while IPA (IPA with a sufficiently high purity, specifically, for example, IPA with a purity of 99 wt % or higher) is recovered in the spin drying step, the IPA is recovered in a state where it is mixed with the rinse liquid (water in this case) (i.e., diluted with water) in the organic solvent supplying step. Therefore, the recovery tank 60 stores a mixed fluid containing water that has been supplied to the substrate W in the processing unit 4 and then recovered, and IPA that has been supplied to the substrate W in the processing unit 4 and then recovered.

[0063] A circulation pipe (dehydration circulation pipe) 62 is connected to the recovery tank 60. Specifically, one end and the other end of the dehydration circulation pipe 62 are both connected to the recovery tank 60. The dehydration circulation pipe 62 forms a circulation path through which the mixed fluid stored in the recovery tank 60 flows out of the recovery tank 60 and circulates back to the recovery tank 60.

[0064] A dehydrator (separator) 621 is provided in the dehydration circulation pipe 62. The dehydrator 621 separates water from the mixed fluid that flows therein and dehydrates it. The configuration of the dehydrator 621 will be described later.

[0065] The dehydration circulation pipe 62 includes a first pipe section 62a, a second pipe section 62b, and a bypass pipe section 62c. Specifically, the dehydration circulation pipe 62 has a first position Q1 and a second position Q2. The first pipe section 62a connects the downstream side of the second position Q2 to the upstream side of the first position Q1. The second pipe section 62b connects the downstream side of the first position Q1 to the upstream side of the second position Q2. The bypass pipe section 62c connects the downstream side of the first position Q1 to the upstream side of the second position Q2 via a different path from the second pipe section 62b. For example, the dehydrator 621 is provided in the first pipe section 62a. For example, the second position Q2 is located downstream of the first position Q1 and upstream of the dehydrator 621. For example, the recovery tank 60 is provided in the second pipe section 62b. In other words, the first position Q1 is a position downstream of the dehydrator 621 and upstream of the recovery tank 60, and the second position Q2 is a position downstream of the recovery tank 60 and upstream of the dehydrator 621.

[0066] A pump (spin-off liquid pump) 622 and a heater 623 are provided in the dehydration circulation pipe 62. Here, for example, the spin-off liquid pump 622 and the heater 623 are both provided in the first pipe section 62a. As an example, the heater 623 is provided upstream of the dehydrator 621, and the spin-off liquid pump 622 is provided upstream of the heater 623.

[0067] The liquid feeding pump 622 on the dehydration side feeds the mixed fluid in the dehydration circulation pipe 62 at a pressure (circulation pressure) P1 required for circulation. Further, the liquid feeding pump 622 on the dehydration side pressurizes the mixed fluid to a separation pressure P2 higher than the circulation pressure P1 (P1 < P2). As will be described later, the higher the separation pressure P2, the higher the water separation efficiency in the dehydrator 621. Also, as will be described later, the higher the separation pressure P2, the higher the heating temperature T2 can be increased, and the higher the heating temperature T2, the higher the separation efficiency. Therefore, the separation pressure P2 is preferably set to the highest possible value within a range that does not exceed the pressure resistance values of the pipe portion through which the pressurized mixed fluid flows and the equipment provided therein.

[0068] The heater 623 heats the mixed fluid to a predetermined heating temperature T2. Here, the heating temperature T2 is higher than the boiling point (reference boiling point) T1 of the organic solvent (here IPA) under atmospheric pressure and lower than the boiling point (pressurized boiling point) T3 of the organic solvent (here IPA) under the separation pressure P2 (T1 < T2 < T3). As will be described later, the higher the heating temperature T2, the higher the water separation efficiency in the dehydrator 621. On the other hand, when the temperature of the mixed fluid exceeds the boiling point of IPA, IPA, which occupies most of the mixed fluid, may boil, and there is a risk that extremely high pressure will be suddenly applied to the pipe portion through which the mixed fluid flows and the equipment provided therein. Therefore, here, by pressurizing the mixed fluid to the separation pressure P2 (that is, the separation pressure P2 defined in advance in consideration of the pressure resistance values of the pipe portion through which the mixed fluid flows, etc.), the boiling point of IPA is increased to the pressurized boiling point T3 higher than the reference boiling point T1. Then, even if the mixed fluid is heated to a temperature higher than the reference boiling point T1, as long as the temperature does not exceed the pressurized boiling point T3, IPA contained in the mixed fluid will not boil. That is, the mixed fluid can be heated to a temperature higher than the reference boiling point T1 without boiling the IPA contained in the mixed fluid. As a result, the separation efficiency can be increased. Needless to say, the higher the separation pressure P2, the higher the pressurized boiling point T3, and the higher the heating temperature T2 can be increased.

[0069] Switching valves 624a and 624b are provided in the dehydration circulation pipe 62. The switching valves 624a and 624b switch between a state in which a fluid circulates through the first pipe section 62a, the second pipe section 62b, and the bypass pipe section 62c (first circulation state X1) (FIG. 8) and a state in which a fluid circulates through the first pipe section 62a and the bypass pipe section 62c (second circulation state X2) (FIG. 9). Here, for example, the first switching valve 624a is provided near the upstream end (first position Q1) of the second pipe section 62b, and the second switching valve 624b is provided near the downstream end (second position Q2) of the second pipe section 62b. When the dehydration-side liquid pump 622 is operated with both switching valves 624a, 624b open, the fluid circulates through the first piping section 62a, the second piping section 62b, and the bypass piping section 62c. That is, a first circulation state X1 is established. On the other hand, when the dehydration-side liquid pump 622 is operated with both switching valves 624a, 624b closed, the fluid circulates through the first piping section 62a and the bypass piping section 62c. That is, a second circulation state X2 is established.

[0070] Here, the dehydration-side liquid pump 622 pressurizes the mixed fluid to a separation pressure P2 while the mixed fluid is circulating through the first piping portion 62a and the bypass piping portion 62c (second circulation state X2). Similarly, the heater 623 pressurizes the mixed fluid to a heating temperature T2 while in the second circulation state X2. Therefore, the pressurized and heated mixed fluid flows through the first piping portion 62a and the bypass piping portion 62c, but the pressurized and heated mixed fluid does not flow through the second piping portion 62b (strictly speaking, the piping portion of the second piping portion 62b that is downstream of the first switching valve 624a and upstream of the second switching valve 624b).

[0071] Therefore, the first piping section 62a, the bypass piping section 62c, and the devices provided therein (e.g., the dehydrator 621, the dehydration-side liquid supply pump 622, and the heater 623) are required to have pressure resistance sufficient to withstand the separation pressure P2 and heat resistance sufficient to withstand the heating temperature T2, but the second piping section 62b (strictly speaking, the piping section in the second piping section 62b downstream of the first switching valve 624a and upstream of the second switching valve 624b) and the devices provided therein (e.g., the recovery tank 60) do not need to have pressure resistance sufficient to withstand the separation pressure P2 and heat resistance sufficient to withstand the heating temperature T2. In other words, the second piping section 62b and the devices provided therein may have lower pressure resistance and heat resistance than the first piping section 62a, the bypass piping section 62c, and the devices provided therein. As an example, the first piping section 62a and the bypass piping section 62c are formed of pressure-resistant piping (for example, metal piping), and the piping section of the second piping section 62b downstream of the first switching valve 624a and upstream of the second switching valve 624b is formed of piping that is not pressure-resistant (for example, resin piping). Furthermore, the recovery tank 60 does not need to be a pressure vessel (pressure tank) and may be formed of, for example, an atmospheric pressure tank.

[0072] A buffer tank 60s for storing the mixed fluid is provided in the dehydration circulation pipe 62. The buffer tank 60s is provided in the first pipe section 62a or the bypass pipe section 62c (in the illustrated example, the bypass pipe section 62c). As will be described later, in a second circulation state X2 in which the mixed fluid circulates through the first pipe section 62a and the bypass pipe section 62c, water contained in the mixed fluid is separated in the dehydrator 621. During this period, the mixed fluid is replenished from the buffer tank 60s in an amount equivalent to the separated water into the pipe, thereby maintaining the state in which the mixed fluid circulates through the first pipe section 62a and the bypass pipe section 62c. The buffer tank 60s does not need to have a capacity comparable to that of the recovery tank 60. In other words, the buffer tank 60s may have a smaller capacity than the recovery tank 60. Specifically, the buffer tank 60s only needs to have a capacity that can store at least the minimum amount of mixed fluid required to maintain circulation in a state where separation of water from the mixed fluid circulating through the first piping portion 62a and the bypass piping portion 62c is completed (specifically, as will be described later, this is the state after the mixed fluid has been circulated through the first piping portion 62a and the bypass piping portion 62c while the vacuum pump 531 is operated for a predetermined period of time, and the concentrated fluid is circulating through the first piping portion 62a and the bypass piping portion 62c). The buffer tank 60s is pressure-resistant enough to withstand the separation pressure P2 and heat-resistant enough to withstand the heating temperature T2. As an example, the buffer tank 60s is formed by a pressure vessel (pressure tank).

[0073] Various sensors may be provided in the dehydration circulation pipe 62. For example, the dehydration circulation pipe 62 may be provided with a concentration sensor 625 that measures the concentration of IPA contained in the mixed fluid circulating through the dehydration circulation pipe 62, a pressure sensor 626 that detects the pressure of the mixed fluid circulating through the dehydration circulation pipe 62, a temperature sensor 627 that detects the temperature of the mixed fluid circulating through the dehydration circulation pipe 62, a flow rate sensor (flow meter) 628 that measures the flow rate of the mixed fluid circulating through the dehydration circulation pipe 62, etc. Each of the sensors 625, 626, 627, 628 may be provided in the first piping portion 62a or the bypass piping portion 62c, for example, as long as it has pressure resistance sufficient to withstand the separation pressure P2 and heat resistance sufficient to withstand the heating temperature T2. However, if it is difficult to use such sensors, the sensors are provided in the second piping portion 62b. In the illustrated example, the concentration sensor 625 is provided in the second piping portion 62b, and the pressure sensor 626, the temperature sensor 627, and the flow rate sensor 628 are provided in the first piping portion 62a. In the illustrated example, the concentration sensor 625 is provided downstream of the first position Q1, the pressure sensor 626 is provided downstream of the dehydration-side liquid supply pump 622, the temperature sensor 627 is provided downstream of the heater 623, and the flow rate sensor 628 is provided upstream of the dehydration-side liquid supply pump 622.

[0074] (b) Dehydrator 621 Next, the dehydrator 621 will be described with reference to Fig. 4 in addition to Fig. 3. Fig. 4 is a side cross-sectional view that schematically shows an example of the configuration of the dehydrator 621.

[0075] The dehydrator 621 includes a separation membrane 51 and a housing 52 .

[0076] The separation membrane 51 is a membrane that allows water to pass through but does not allow an organic solvent (IPA in this case) to pass through. Specifically, the separation membrane 51 is a zeolite membrane made of zeolite, for example. Zeolite is a material that has a basic unit of a tetrahedral structure (for example, (SiO4) 4- and (AlO4) 5-The separation membrane 51 has a crystal structure in which zeolite particles (basic units each including at least one of the above) are interconnected. Specifically, the separation membrane 51 has a configuration in which a cylindrical substrate 511 is provided with countless cells 512 that penetrate the substrate in the axial direction. The cells 512 serve as flow paths for the mixed fluid within the separation membrane 51. In this case, the entire substrate 511 may be made of zeolite, or only the inner circumferential surface of each cell 512 may be made of zeolite.

[0077] The housing 52 is a hollow cylindrical member and accommodates the separation membrane 51 therein. A pair of sealing members 520 are provided between the housing 52 and the separation membrane 51 accommodated therein to seal the space therebetween. Each sealing member 520 is, for example, ring-shaped and is provided at one end and the other end of the separation membrane 51 in the axial direction. The internal space of the housing 52 is separated by the separation membrane 51 into an intra-cell space V1, which is the internal space of the separation membrane 51 (i.e., the internal space of each cell 512), and a separation space V2, which is the external space of the separation membrane 51. The housing 52 is also provided with an inlet 521, a first outlet 522, and a second outlet 523. The inlet 521 is provided on one end face of the housing 52 in the axial direction and communicates with the intra-cell space V1 through one opening of each cell 512. The first outlet 522 is provided on the other end face in the axial direction of the housing 52, and communicates with the intra-cell space V1 through the other opening of each cell 512. The second outlet 523 is provided on the side face (peripheral surface) of the housing 52, and communicates with the separation space V2.

[0078] A dehydration circulation pipe 62 is connected to the inlet 521 and the first outlet 522. Meanwhile, a separation pipe 53 equipped with a vacuum pump 531 is connected to the second outlet 523. The mixed fluid flowing through the dehydration circulation pipe 62 flows from the inlet 521 into the dehydrator 621 (specifically, into the intra-cell space V1) and flows through the intra-cell space V1. When the vacuum pump 531 provided in the separation pipe 53 is operated in this state, the separation space V2 is decompressed, and a pressure difference is created between the intra-cell space V1 and the separation space V2. The separation membrane 51 separating the intra-cell space V1 and the separation space V2 is a membrane that allows water to pass through but not IPA. Therefore, when a pressure difference is created between the intra-cell space V1 and the separation space V2, water (water molecules) contained in the mixed fluid that has flowed into the intra-cell space V1 passes through the separation membrane 51, reaches the separation space V2, and flows into the separation pipe 53 through the second outlet 523. In this way, water is separated from the mixed fluid. On the other hand, IPA (IPA molecules) contained in the mixed fluid that has flowed into the intra-cell space V1 cannot pass through the separation membrane 51, so it flows through the intra-cell space V1 and flows into the dehydration circulation pipe 62 through the first outlet 522. In this way, the mixed fluid flows out of the dehydrator 621 with a higher IPA concentration than when it flowed into the dehydrator 621. The IPA concentration in the mixed fluid increases with each repeated passage through the dehydrator 621.

[0079] Here, the mixed fluid flowing into the dehydrator 621 is pressurized to a separation pressure P2 and heated to a heating temperature T2. When a pressurized mixed fluid flows into the intra-cell space V1, the pressure difference between the intra-cell space V1 and the separation space V2 is larger than when an unpressurized mixed fluid flows in. As a result, the number of water molecules passing through the separation membrane 51 per unit time increases. Furthermore, when the mixed fluid is heated, the average kinetic energy of the water molecules contained in the mixed fluid increases compared to when the mixed fluid is not heated. As a result, the number of water molecules passing through the separation membrane 51 per unit time increases. In this way, the separation efficiency (dehydration efficiency) is improved by pressurizing and heating the mixed fluid flowing into the dehydrator 621.

[0080] The configuration of the separation pipe 53 into which the water separated from the mixed fluid flows can be specified as appropriate. For example, a condenser 532 is provided in the separation pipe 53 at a position upstream of the vacuum pump 531. A drain pipe 54 is connected to the condenser 532 to guide the water condensed therein. A decomposer 541 is provided in the drain pipe 54 to decompose trace amounts of an organic solvent (IPA in this case) contained in the water flowing therethrough to increase the purity of the water. The decomposer 541 may, for example, electrolyze the IPA contained in the water to increase the purity of the water. In this case, the decomposer 541 may include, for example, a tank for temporarily storing the water flowing through the drain pipe 54, a pair of electrodes immersed in the water stored in the tank, and a power supply unit for supplying power to the pair of electrodes to create a potential difference between them. The drain pipe 54 may be connected, for example, to a rinse liquid supply source 433b ( FIG. 2 ) of the processing unit 4 or to a water recovery line in the factory. For example, when the drain pipe 54 is connected to the rinse liquid supply source 433b, the water separated from the mixed fluid and flowing into the separation pipe 53 is condensed in the condenser 532, flows into the drain pipe 54, has its purity increased in the decomposer 541, is guided to the rinse liquid supply source 433b, and is discharged as the rinse liquid from the rinse liquid nozzle 43b. That is, in this case, the water separated from the mixed fluid is reused as the rinse liquid.

[0081] (c) Purification tank 70 Referring again to Figure 3, the purification tank 70 is connected to the recovery tank 60 via the first liquid supply pipe 71 and the dehydration circulation pipe 62. That is, one end of the first liquid supply pipe 71 is connected to the purification tank 70, and the other end of the first liquid supply pipe 71 is connected to the dehydration circulation pipe 62. As an example, the other end of the first liquid supply pipe 71 is connected to the first pipe section 62a of the dehydration circulation pipe 62 (for example, a position in the first pipe section 62a downstream of the heater 623 and upstream of the dehydrator 621). A first liquid supply valve 711 is provided in the first liquid supply pipe 71. When the first liquid supply valve 711 is opened in a state in which a fluid (hereinafter also referred to as a "concentrated fluid") in which the concentration (purity) of IPA has been sufficiently increased (to the extent that it can be supplied to the substrate W) by separating water from the mixed fluid is obtained in the first piping section 62a and the bypass piping section 62c, the concentrated fluid is guided to the first liquid supply piping 71 and flows into the purification tank 70, where it is stored.

[0082] A circulation pipe (purification circulation pipe) 72 is connected to the purification tank 70. Specifically, both one end and the other end of the purification circulation pipe 72 are connected to the purification tank 70. The purification circulation pipe 72 forms a circulation path through which the concentrated fluid stored in the purification tank 70 flows out of the purification tank 70 and circulates back to the purification tank 70.

[0083] The purification circulation pipe 72 is provided with a pump (purification-side liquid feed pump) 721 and an on-off valve 722. As an example, the on-off valve 722 is provided downstream of the purification-side liquid feed pump 721 and upstream of the purification tank 70. The purification-side liquid feed pump 721 feeds the concentrated fluid in the purification circulation pipe 72 at a pressure required for circulation. With the on-off valve 722 open, the purification-side liquid feed pump 721 feeds the concentrated fluid at a pressure required for circulation, causing the concentrated fluid stored in the purification tank 70 to circulate through the purification circulation pipe 72.

[0084] The purification circulation pipe 72 is provided with a filter 723 and a temperature regulator 724. For example, the filter 723 is provided downstream of the purification-side liquid pump 721 and upstream of the purification tank 70, and the temperature regulator 724 is provided downstream of the purification-side liquid pump 721 and upstream of the filter 723. The filter 723 captures substances to be removed (e.g., particles, metals, etc.) contained in the concentrated fluid flowing through the purification circulation pipe 72. When the concentrated fluid passes through the filter 723, the substances to be removed are removed from the concentrated fluid, thereby increasing the purity of the concentrated fluid. An air vent pipe 7231 may be connected to the filter 723. The temperature regulator 724 is a device having cooling and heating capabilities, and for example, is an electronic cooler / heater that performs electronic cooling and heating using a Peltier element. When a high-temperature fluid passes through the filter 723, the performance of the filter 723 may be degraded due to thermal expansion, etc. Therefore, here, the temperature regulator 724 cools the concentrated fluid circulating through the purification circulation pipe 72 to a predetermined temperature (for example, room temperature) as needed, thereby preventing the performance of the filter 723 from deteriorating.

[0085] Various sensors may be provided in the purification circulation pipe 72. For example, the purification circulation pipe 72 may be provided with a pressure sensor 725 that detects the pressure of the concentrated fluid circulating through the purification circulation pipe 72, a temperature sensor 726 that detects the temperature of the concentrated fluid circulating through the purification circulation pipe 72, a particle counter (not shown) that counts the number of particles contained in the concentrated fluid circulating through the purification circulation pipe 72, etc. In the example shown in the figure, the pressure sensor 725 is provided near the downstream side of the purification-side liquid feed pump 721, and the temperature sensor 726 is provided near the downstream side of the temperature regulator 724.

[0086] (d) Supply Tank 80 The supply tank 80 is connected to the purification tank 70 via a second liquid feed pipe 81 and a purification circulation pipe 72. That is, one end of the second liquid feed pipe 81 is connected to the supply tank 80, and the other end of the second liquid feed pipe 81 is connected to the purification circulation pipe 72. As an example, the other end of the second liquid feed pipe 81 is connected to a position in the purification circulation pipe 72 that is upstream of the filter 723 and downstream of the purification-side liquid feed pump 721. However, the other end of the second liquid feed pipe 81 may be connected directly to the purification tank 70 without going through the purification circulation pipe 72. A second liquid feed valve 811 is provided in the second liquid feed pipe 81. When the purification tank 70 contains a concentrated fluid (hereinafter referred to as "purified fluid") with a sufficiently high level of cleanliness (enough to be supplied to the substrate W), and the second liquid supply valve 811 is opened, the purified fluid is guided to the second liquid supply pipe 81 and flows into the supply tank 80, where it is stored.

[0087] The supply tank 80 may be connected to a new liquid supply source 821 through a new liquid pipe 82. In this case, one end of the new liquid pipe 82 is connected to the supply tank 80, and the other end of the new liquid pipe 82 is connected to the new liquid supply source 821. The new liquid supply source 821 is a supply source of unused IPA that has never been supplied to the substrate W (IPA with a sufficiently high purity, specifically, for example, IPA with a purity of 99 wt % or more). A new liquid valve 822 is provided on the new liquid pipe 82. When the new liquid valve 822 is opened, unused IPA is guided into the new liquid pipe 82 and flows into the supply tank 80, where it is stored.

[0088] The supply tank 80 is connected to the organic solvent nozzle 43c through a third liquid feed pipe 83. That is, one end of the third liquid feed pipe 83 is connected to the supply tank 80, and the other end of the third liquid feed pipe 83 is connected to the organic solvent nozzle 43c (specifically, the organic solvent pipe 432c connected to the organic solvent nozzle 43c). In this example, the third liquid feed pipe 83 is connected to the organic solvent nozzles 43c provided in each of the multiple processing units 4 belonging to the same tower. A pump (supply-side liquid feed pump) 831 is provided on the third liquid feed pipe 83. When the organic solvent valve 431c is opened, the purified fluid stored in the supply tank 80 is fed to the organic solvent nozzle 43c by the supply-side liquid feed pump 831 and discharged from the organic solvent nozzle 43c.

[0089] The third liquid feed pipe 83 may be provided with a filter 832 that captures substances to be removed that are contained in the purified fluid fed through the third liquid feed pipe 83, and a temperature regulator 833 that adjusts the temperature of the purified fluid fed through the third liquid feed pipe 83 (i.e., heats or cools the purified fluid to a predetermined temperature). In the example shown in the figure, the temperature regulator 833 is provided downstream of the supply-side liquid feed pump 831, and the filter 832 is provided downstream of the temperature regulator 833. In addition, various sensors may be provided in the third liquid feed pipe 83. For example, the third liquid feed pipe 83 may be provided with a pressure sensor 834 that detects the pressure of the purified fluid fed through the third liquid feed pipe 83, a temperature sensor 835 that detects the temperature of the purified fluid fed through the third liquid feed pipe 83, and the like. In the example shown in the figure, the pressure sensor 834 is provided near the downstream side of the supply-side liquid feed pump 831, and the temperature sensor 835 is provided downstream near the temperature regulator 833.

[0090] <3-2. Operation> The flow of the process carried out in the organic solvent recovery section 5 will be described with reference to Figs. 5 to 14. Fig. 5 is a diagram showing an example of the flow of the process carried out in the organic solvent recovery section 5. Fig. 6 is a diagram showing an example of the flow of the process for separating water from a mixed fluid. Figs. 7 to 14 are diagrams schematically showing the state of the organic solvent recovery section 5 in each step. For ease of explanation, in Figs. 7 to 14, pipes through which a fluid flows are shown with solid lines, and pipes through which no fluid flows are shown with dashed lines.

[0091] The organic solvent recovery unit 5 operates under the control of the control unit 6. That is, based on input information from sensors (concentration sensor 625, pressure sensors 626, 725, 834, temperature sensors 627, 726, 835, flow rate sensor 628, etc.), the control unit 6 controls pumps (dehydration-side liquid feed pump 622, vacuum pump 531, purification-side liquid feed pump 721, and supply-side liquid feed pump 831), valves (recovery valve 611, pair of switching valves 624a, 624b, first liquid feed valve 711, on-off valve 722, second liquid feed valve 811, and new liquid valve 822, etc.), heater 623, condenser 532, decomposer 541, temperature regulators 724, 833, etc., and thereby a series of operations in the organic solvent recovery unit 5 proceeds.

[0092] Step S1 First, the recovery valve 611 is opened when the recovery tank 60 is empty. Then, the liquid collected in the cup 42 in the organic solvent supplying step and the spin drying step is guided to the recovery pipe 61 and flows into the recovery tank 60. As a result, a mixed fluid containing water that has been supplied to the substrate W and then recovered, and IPA that has been supplied to the substrate W and then recovered, is stored in the recovery tank 60 ( FIG. 7 ) (storing step). When a predetermined amount of mixed fluid has been stored in the recovery tank 60, the recovery valve 611 is closed.

[0093] Step S2 Next, a process is performed to separate water from the mixed fluid stored in the recovery tank 60. This process will be specifically described with reference to FIGS.

[0094] First, with both of the switching valves 624a, 624b open, the spin-hydration-side liquid-feed pump 622 feeds the mixed fluid at a circulation pressure P1. As an example, the circulation pressure P1 is 0.1 MPa or more and 0.2 MPa or less. As a result, the mixed fluid stored in the recovery tank 60 fills the first piping portion 62a, the second piping portion 62b, the bypass piping portion 62c, and the buffer tank 60s, and the mixed fluid circulates through the first piping portion 62a, the second piping portion 62b, and the bypass piping portion 62c (first circulation state X1) (step S201: filling step) (FIG. 8). At this time, the mixed fluid flows through the first piping section 62a and branches at the first position Q1 into a route that flows through the second piping section 62b (i.e., a route that passes through the recovery tank 60) and a route that flows through the bypass piping section 62c (i.e., a route that does not pass through the recovery tank 60), and the mixed fluid that has passed through each route merges at the second position Q2 and flows again through the first piping section 62a.

[0095] Next, while maintaining the circulation pressure P1, the pair of switching valves 624a, 624b are both closed. This separates the second piping portion 62b, and a state (second circulation state X2) is established in which the mixed fluid circulates through the first piping portion 62a and the bypass piping portion 62c (step S202: circulation step) (FIG. 9). At this time, the mixed fluid that has flowed through the first piping portion 62a flows into and through the bypass piping portion 62c at the first position Q1, and then flows into and through the first piping portion 62a again at the second position Q2.

[0096] Next, pressurization of the mixed fluid begins (step S203: pressurization step). Specifically, the pressure of the dehydration-side liquid pump 622 is switched from the circulation pressure P1 to the separation pressure P2. As a result, the mixed fluid circulating through the first piping portion 62a and the bypass piping portion 62c is pressurized to the separation pressure P2. As an example, the separation pressure P2 is preferably 0.5 MPa or higher, and particularly preferably 1.0 MPa or higher. Thereafter, heating of the mixed fluid begins (step S204: heating step). Specifically, the heater 623 heats the mixed fluid circulating through the first piping portion 62a and the bypass piping portion 62c to a heating temperature T2. The heating temperature T2 is preferably 100°C or higher, and particularly preferably 120°C or higher. As described above, in this state where the mixed fluid is circulating through the first piping portion 62a and the bypass piping portion 62c (second circulation state X2), after the dehydration-side liquid pump 622 pressurizes the mixed fluid to the separation pressure P2 (i.e., after the boiling point of IPA increases to the pressurized boiling point T3), the heater 623 heats the mixed fluid to the heating temperature T2. Therefore, the IPA does not boil during heating.

[0097] Next, while the mixed fluid continues to be pressurized and heated, the vacuum pump 531 is started to operate. By operating the vacuum pump 531, the separation space V2 is depressurized, and a pressure difference is created between the intra-cell space V1 and the separation space V2. This pressure difference causes water contained in the mixed fluid that has flowed into the intra-cell space V1 to pass through the separation membrane 51, reach the separation space V2, and flow into the separation piping 53. That is, when the mixed fluid circulating through the first piping portion 62a and the bypass piping portion 62c flows into and passes through the dehydrator 621, the water contained in the mixed fluid is separated (step S205: separation step) ( FIG. 10 ). Here, the mixed fluid flowing into the dehydrator 621 is pressurized to a separation pressure P2 and heated to a heating temperature T2, so that water is efficiently separated from the mixed fluid. Here, since the mixed fluid flows into the intra-cell space V1 in a pressurized state, a certain degree of pressure difference occurs between the intra-cell space V1 and the separation space V2 before the vacuum pump 531 is operated (i.e., when the vacuum pump 531 is not operated and the pressurized mixed fluid flows into the dehydrator 621). Therefore, even in this state, water separation is progressing to some extent. From this state, further operation of the vacuum pump 531 increases the pressure difference sufficiently, and water separation is promoted.

[0098] Thereafter, the vacuum pump 531 continues to operate for a predetermined time. During this time, the mixed fluid continues to be pressurized and heated. During this time, the mixed fluid circulating through the first piping portion 62a and the bypass piping portion 62c repeatedly passes through the dehydrator 621, thereby increasing the concentration of IPA in the mixed fluid. During this time, the mixed fluid is replenished from the buffer tank 60s with an amount of mixed fluid equivalent to the separated water, thereby maintaining the state in which the mixed fluid circulates through the first piping portion 62a and the bypass piping portion 62c. Here, the time required for the IPA concentration in the mixed fluid circulating through the first piping portion 62a and the bypass piping portion 62c and the mixed fluid stored in the buffer tank 60s to increase sufficiently (to the extent that it can be supplied to the substrate W) (i.e., the time required for a concentrated fluid to be obtained) is determined in advance by measurement, calculation, or the like, and is specified as the predetermined time. Therefore, after a predetermined time has elapsed since the start of operation of the vacuum pump 531, the concentrated fluid is circulating through the first piping portion 62a and the bypass piping portion 62c, and the concentrated fluid is stored in the buffer tank 60s. After a predetermined time has elapsed since the start of operation of the vacuum pump 531 (YES in step S206), the operation of the vacuum pump 531 is stopped. This causes the separation of water in the dehydrator 621 to almost stop (step S207) (FIG. 11).

[0099] Next, heating of the concentrated fluid is stopped (step S208). Specifically, the heater 623 stops heating. Thereafter, the system waits for the temperature of the concentrated fluid circulating through the first piping portion 62a and the bypass piping portion 62c to drop to a temperature lower than the reference boiling point T1 (82.3°C for IPA) (step S209). When the temperature of the concentrated fluid drops below the reference boiling point T1 (YES in step S209), pressurization of the concentrated fluid is stopped (step S210). Specifically, the pressure of the dehydration-side liquid pump 622 is switched from separation pressure P2 to circulation pressure P1. Thus, in this state, while the concentrated fluid is circulating through the first piping portion 62a and the bypass piping portion 62c, the heater 623 stops heating, and after the temperature of the concentrated fluid drops below the reference boiling point T1, the dehydration-side liquid pump 622 stops pressurizing the concentrated fluid. That is, the pressurized state is maintained until the temperature of the concentrated fluid is lowered to a temperature lower than the reference boiling point T1, so the IPA does not boil during the temperature drop.

[0100] Thereafter, the first liquid supply valve 711 is opened. Then, the concentrated fluid in the first piping section 62a, the bypass piping section 62c, and the buffer tank 60s is sent to the purification tank 70 through the first liquid supply piping 71. As a result, the concentrated fluid is stored in the purification tank 70 (step S211) (FIG. 12).

[0101] Next, the processing of steps S201 to S211 is repeated again. As the number of repetitions increases, the amount of mixed fluid stored in the recovery tank 60 decreases, and the amount of concentrated fluid stored in the purification tank 70 increases. When the recovery tank 60 becomes empty (YES in step S212) (FIG. 13), the processing of step S2 (i.e., the processing of separating water from the mixed fluid stored in the recovery tank 60) is terminated. Needless to say, the recovery tank 60 may be considered to be empty and the processing of step S2 may be terminated when the remaining amount of mixed fluid in the recovery tank 60 becomes sufficiently small.

[0102] Step S3 Next, a process for increasing the cleanliness of the concentrated fluid stored in the purification tank 70 is performed. Specifically, the on-off valve 722 is opened, and the purification-side liquid supply pump 721 sends the concentrated fluid at a pressure required for circulation. As a result, the concentrated fluid stored in the purification tank 70 circulates through the purification circulation pipe 72 ( FIG. 14 ). This state continues for a predetermined time. During this time, the concentrated fluid circulating through the purification circulation pipe 72 passes through the filter 723 repeatedly, thereby increasing the cleanliness of the concentrated fluid. Here, the time required for the cleanliness of the concentrated fluid circulating through the purification circulation pipe 72 to increase sufficiently (to the extent that it can be supplied to the substrate W) (i.e., the time required for the purified fluid to be obtained) is determined in advance by measurement, calculation, or the like, and specified as the predetermined time. Therefore, the purified fluid is stored in the purification tank 70 when a predetermined time has elapsed since the start of circulation. When a predetermined time has elapsed since the start of circulation, the on-off valve 722 is closed.

[0103] Step S4 Subsequently, the second liquid supply valve 811 is opened. Then, the purified fluid in the purification tank 70 is sent to the supply tank 80 through the second liquid supply pipe 81. As a result, the purified fluid is stored in the supply tank 80 (FIG. 15). For example, when the entire amount of the purified fluid in the purification tank 70 has been sent to the supply tank 80, the second liquid supply valve 811 is closed. Thereafter, when the organic solvent valve 431c is opened, the purified fluid stored in the supply tank 80 is sent to the organic solvent nozzle 43c side by the supply-side liquid supply pump 831 and is discharged from the organic solvent nozzle 43c. In other words, the purified fluid is supplied to the substrate W. Note that the purified fluid may pass through a filter 832 on its way through the third liquid supply pipe 83 to increase its cleanliness, and its temperature may be adjusted by a temperature regulator 833 as necessary. Furthermore, when the amount of purified fluid stored in the supply tank 80 falls below a predetermined amount, the new liquid valve 822 may be opened to replenish the supply tank 80 with unused IPA.

[0104] This series of processes (steps S1 to S4) is repeated in the organic solvent recovery section 5. However, the next step S1 may be started before the process of step S4 is completed (for example, when the process of step S3 is completed).

[0105] <4. Effects> The substrate processing apparatus 100 according to the above embodiment includes a rinse liquid supply unit (rinse liquid nozzle) 43b that supplies a rinse liquid containing water to the substrate W, an organic solvent supply unit (organic solvent nozzle) 43c that supplies an organic solvent (e.g., IPA) to the substrate W, a recovery tank 60 that stores a mixed fluid containing water that has been supplied to the substrate W and then recovered, and an organic solvent that has been supplied to the substrate W and then recovered, a circulation pipe (spin-off circulation pipe) 62 connected to the recovery tank 60, a dehydrator 621 provided in the spin-off circulation pipe 62 and equipped with a separation membrane 51 that allows water to pass through but does not allow organic solvent to pass through, a pump (spin-off liquid pump) 622 provided in the spin-off circulation pipe 62, and a heater 623 provided in the spin-off circulation pipe 62. The dehydration circulation pipe 62 is provided with a first piping section 62a connecting the downstream side of the second position Q2 to the upstream side of the first position Q1, a second piping section 62b connecting the downstream side of the first position Q1 to the upstream side of the second position Q2, and a bypass piping section 62c connecting the downstream side of the first position Q1 to the upstream side of the second position Q2 via a path different from that of the second piping section 62b. A dehydrator 621 is provided in the first piping section 62a or the bypass piping section 62c. When the mixed fluid is circulating through the first piping section 62a and the bypass piping section 62c, a dehydrator-side liquid pump 622 pressurizes the mixed fluid to a separation pressure P2 higher than the circulation pressure P1 required for circulation, and a heater 623 heats the mixed fluid to a predetermined heating temperature T2.

[0106] With this configuration, the pressurized and heated mixed fluid can be flowed into the dehydrator 621, thereby enabling efficient separation of water from the mixed fluid. Furthermore, with this configuration, the pressurized and heated mixed fluid does not flow through the second piping section 62b, so there is no need for the second piping section 62b and the equipment provided therein to have the same pressure resistance as the first piping section 62a, the bypass piping section 62c, and the equipment provided therein (i.e., pressure resistance capable of withstanding a separation pressure P2 higher than the circulation pressure P1). Therefore, the device can be made compact while still improving separation efficiency.

[0107] Furthermore, in the above embodiment, the recovery tank 60 is provided in the second piping section 62b. With this configuration, the pressurized and heated mixed fluid does not flow into the recovery tank 60. Therefore, the recovery tank 60 does not need to be pressure-resistant enough to withstand the separation pressure P2. This allows the recovery tank 60 to be formed, for example, from a container (e.g., an atmospheric pressure tank) rather than a pressure vessel (pressure tank), making the recovery tank 60 more compact.

[0108] In the above embodiment, the heating temperature T2 is higher than the boiling point (normal boiling point) T1 of the organic solvent (e.g., IPA) under atmospheric pressure and lower than the boiling point (pressurized boiling point) T3 of the organic solvent under separation pressure P2. This configuration allows the temperature of the mixed fluid to be sufficiently increased without boiling the organic solvent. Therefore, high separation efficiency can be achieved while ensuring safety.

[0109] In the above embodiment, in a state where the mixed fluid is circulating through the first piping portion 62a and the bypass piping portion 62c (second circulation state X2), the dehydration-side liquid pump 622 pressurizes the mixed fluid to separation pressure P2, and then the heater 623 heats the mixed fluid to heating temperature T2. With this configuration, heating is performed after the boiling point is increased by pressurization, so the organic solvent does not boil during heating.

[0110] In the above embodiment, in a state (second circulation state X2) in which a concentrated fluid obtained by separating water from a mixed fluid is circulating through the first piping portion 62a and the bypass piping portion 62c, the heater 623 stops heating, and after the temperature of the concentrated fluid becomes lower than the boiling point of the organic solvent under atmospheric pressure, the dehydration-side liquid supply pump 622 stops pressurizing the concentrated fluid. With this configuration, the concentrated fluid is maintained in a pressurized state until the temperature is lowered to a temperature lower than the boiling point (reference boiling point) T1 of the organic solvent under atmospheric pressure, so the organic solvent does not boil during the temperature drop.

[0111] Furthermore, the substrate processing apparatus 100 according to the above embodiment includes a vacuum pump 531 that reduces the pressure of the space (separation space) V2 in the dehydrator 621, into which the water that has passed through the separation membrane 51 flows. With this configuration, the pressure in the separation space V2 can be reduced, thereby facilitating separation of the water.

[0112] Moreover, the substrate processing apparatus 100 according to the above embodiment includes a purification tank 70 connected to the recovery tank 60 via the dehydration circulation piping 62 and the liquid supply piping (first liquid supply piping) 71 and storing a concentrated fluid obtained by separating water from the mixed fluid, and a filter 723 provided in a piping (purification circulation piping) 72 connected to the purification tank 70 and capturing substances to be removed that are contained in the concentrated fluid flowing through the purification circulation piping 72. With this configuration, the substances to be removed can be removed from the concentrated fluid obtained by separating water from the mixed fluid, thereby increasing the cleanliness of the concentrated fluid.

[0113] In the above embodiment, the concentrated fluid stored in the purification tank 70 is passed through the filter 723, sent to the organic solvent nozzle 43c, and supplied to the substrate W. That is, the concentrated fluid obtained by separating water from a mixed fluid containing water supplied to the substrate W and recovered thereafter and an organic solvent supplied to the substrate W and recovered thereafter is supplied again to the substrate W after its purity has been increased. Therefore, the amount of organic solvent used and discharged can be reduced (liquefaction saving). IPA is a volatile organic compound (VOC), and reducing its amount used and discharged can reduce the environmental load.

[0114] <5. Variations> The configuration and operation of the substrate processing apparatus 100 according to the above embodiment can be modified as appropriate. In the following description, the same elements as those described in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0115] <5-1. First modified example> The configuration of the organic solvent recovery section 5t according to the first modified example will be described with reference to Fig. 16. Fig. 16 is a diagram schematically showing an example of the organic solvent recovery section 5t.

[0116] The organic solvent recovery section 5t includes a plurality of (two in the illustrated example) recovery tanks 60A, 60B, a plurality of (two in the illustrated example) purification tanks 70A, 70B, and a supply tank 80 (see FIG. 3).

[0117] The recovery tanks 60A, 60B are connected to the cup 42 via a recovery pipe 61t. That is, one end of the recovery pipe 61t is branched, with the end of one branch 61A connected to the first recovery tank 60A and the end of the other branch 61B connected to the second recovery tank 60B. The other end of the recovery pipe 61t is connected to the cup 42 (specifically, the cup-side recovery pipe 424 connected to the cup 42). Recovery valves 611A, 611B are provided at the branch portions 61A, 61B, respectively. When one of the recovery valves 611A is opened, the liquid collected in the cup 42 during the organic solvent supplying step and the spin drying step is guided along the recovery pipe 61t and flows into the first recovery tank 60A, where it is stored. That is, the mixed fluid is stored in the first recovery tank 60A. Similarly, when the other recovery valve 611B is opened, the liquid collected in the cup 42 in the organic solvent supplying step and the spin drying step is guided through the recovery pipe 61t and flows into the second recovery tank 60B, where it is stored. That is, the mixed fluid is stored in the second recovery tank 60B.

[0118] A circulation pipe (spin-drying circulation pipe) 62t is connected to the recovery tanks 60A, 60B. A branch position R1 and a junction position R2 are defined in the spin-drying circulation pipe 62t, and a plurality of branch pipes 620A, 620B (the same number as the recovery tanks 60A, 60B) are provided between them. Each of the plurality of branch pipes 620A, 620B is provided with a recovery tank 60A, 60B. That is, one branch pipe 620A is provided with a first recovery tank 60A, and the other branch pipe 620B is provided with a second recovery tank 60B. One branch pipe 620A is provided with a pair of first valves 621A, 621A on either side of the first recovery tank 60A, and the other branch pipe 620B is provided with a pair of second valves 621B, 621B on either side of the second recovery tank 60B. When the pair of first valves 621A, 621A are opened and the pair of second valves 621B, 621B are closed, a circulation path is formed in which the mixed fluid stored in the first recovery tank 60A flows out of the first recovery tank 60A and circulates back to the first recovery tank 60A again. Conversely, when the pair of first valves 621A, 621A are closed and the pair of second valves 621B, 621B are opened, a circulation path is formed in which the mixed fluid stored in the second recovery tank 60B flows out of the second recovery tank 60B and circulates back to the second recovery tank 60B again.

[0119] Similar to the above embodiment, the dehydration circulation pipe 62t includes a first pipe section 62a, a second pipe section 62b, and a bypass pipe section 62c. Also, similar to the above embodiment, the first pipe section 62a is provided with a dehydrator 621, a dehydration-side liquid pump 622, and a heater 623, and the bypass pipe section 62c is provided with a buffer tank 60s. Also, here, for example, the multiple collection tanks 60A, 60B are both provided in the second pipe section 62b. That is, the first position Q1 is downstream of the dehydrator 621 and upstream of the branch position R1, and the second position Q2 is downstream of the junction position R2 and upstream of the dehydrator 621. Similar to the above embodiment, the dehydration circulation pipe 62t may be provided with various sensors 625, 626, 627, and 628.

[0120] As in the above embodiment, the dehydration circulation pipe 62t is provided with switching valves 624a and 624b. The switching valves 624a and 624b switch between a state in which a fluid circulates through the first pipe portion 62a, the second pipe portion 62b, and the bypass pipe portion 62c (first circulation state) and a state in which a fluid circulates through the first pipe portion 62a and the bypass pipe portion 62c (second circulation state). As in the above embodiment, the dehydration-side liquid pump 622 pressurizes the mixed fluid to a separation pressure P2 when the mixed fluid circulates through the first pipe portion 62a and the bypass pipe portion 62c (second circulation state). Similarly, the heater 623 pressurizes the mixed fluid to a heating temperature T2 when in the second circulation state. For this reason, the first piping section 62a, the bypass piping section 62c, and the devices provided therein (e.g., the dehydrator 621, the dehydration-side liquid supply pump 622, the heater 623, and the buffer tank 60s) are required to have pressure resistance sufficient to withstand the separation pressure P2 and heat resistance sufficient to withstand the heating temperature T2, but the second piping section 62b (strictly speaking, the piping section of the second piping section 62b downstream of the first switching valve 624a and upstream of the second switching valve 624b) and the devices provided therein (e.g., the first recovery tank 60A and the second recovery tank 60B) do not need to have pressure resistance sufficient to withstand the separation pressure P2 or heat resistance sufficient to withstand the heating temperature T2. The first recovery tank 60A and the second recovery tank 60B are formed, for example, by atmospheric pressure tanks.

[0121] The purification tanks 70A, 70B are connected to the recovery tanks 60A, 60B via a first liquid supply pipe 71t and a dehydration circulation pipe 62t. Specifically, one end of the first liquid supply pipe 71t branches, with the end of one branch 71A connected to the first purification tank 70A and the end of the other branch 71B connected to the second purification tank 70B. The other end of the first liquid supply pipe 71t is connected to the first pipe section 62a of the dehydration circulation pipe 62t. First liquid supply valves 711A, 711B are provided at the respective branch sections 71A, 71B. When the first liquid supply valve 711A on the first purification tank 70A side is opened while concentrated fluid is being obtained in the first pipe section 62a and the bypass pipe section 62c, the concentrated fluid is guided along the first liquid supply pipe 71t and flows into the first purification tank 70A, where it is stored. Similarly, when concentrated fluid is obtained in the first piping section 62a and the bypass piping section 62c and the first liquid supply valve 711B on the second purification tank 70B side is opened, the concentrated fluid is guided to the first liquid supply piping 71t and flows into the second purification tank 70B, where it is stored.

[0122] Circulation pipes (purification circulation pipes) 72A and 72B are connected to the first purification tank 70A and the second purification tank 70B, respectively. Similar to the purification circulation pipe 72 according to the above embodiment, each of the purification circulation pipes 72A and 72B is provided with a purification-side liquid feed pump 721, an opening / closing valve 722, a filter 723, a temperature regulator 724, and various sensors 725 and 726.

[0123] The first purification tank 70A and the second purification tank 70B are each connected to the supply tank 80 (FIG. 3) via purification circulation pipes 72A, 72B and a second liquid supply pipe 81t. That is, one end of the second liquid supply pipe 81t is branched, and the end of one branched portion 81A is connected to the purification circulation pipe 72A on the first purification tank 70A side, and the end of the other branched portion 81B is connected to the purification circulation pipe 72B on the second purification tank 70B side. The other end of the second liquid supply pipe 81t is connected to the supply tank 80. Second liquid supply valves 811A, 811B are provided in each of the branched portions 81A, 81B. When the second liquid feed valve 811A on the first purification tank 70A side is opened while purified fluid is being obtained in the first purification tank 70A, the purified fluid in the first purification tank 70A is guided to the second liquid feed piping 81t and flows into the supply tank 80, where it is stored. Similarly, when the second liquid feed valve 811B on the second purification tank 70B side is opened while purified fluid is being obtained in the second purification tank 70B, the purified fluid in the second purification tank 70B is guided to the second liquid feed piping 81t and flows into the supply tank 80, where it is stored.

[0124] In the organic solvent recovery section 5t, a series of processes (steps S1 to S4) (FIG. 5) similar to those in the above embodiment are performed.

[0125] That is, as in the above embodiment, in the organic solvent recovery unit 5t, first, the liquid collected in the cup 42 is transferred to one of the recovery tanks (for example, the first recovery tank 60A), where the mixed fluid is stored (step S1). Next, a process of separating water from the mixed fluid stored in the first recovery tank 60A is performed (step S2). However, in the organic solvent recovery unit 5t, in parallel with this process, the liquid collected in the cup 42 is transferred to the other recovery tank (the second recovery tank 60B), where the mixed fluid is stored. That is, after being transferred to one of the recovery tanks 60A, the liquid collected in the cup 42 is transferred to the other recovery tank 60B without waiting for the recovery tank 60A to become empty (i.e., without waiting for the process of separating water from the mixed fluid stored in the recovery tank 60A to be completed).

[0126] Furthermore, similar to the above embodiment, in the organic solvent recovery unit 5t, the concentrated fluid obtained by separating water from the mixed fluid is sent to the first purification tank 70A or the second purification tank 70B and stored therein. In each of the first purification tank 70A and the second purification tank 70B, when the concentrated fluid is stored therein, a process for increasing the purity of the concentrated fluid is performed (step S3), and the obtained purified fluid is sent to the supply tank 80 (step S4). Here, since multiple purification tanks 70A and 70B are provided, the concentrated fluid can be sent to the other purification tank 70B even while a process for increasing the purity of the concentrated fluid is being performed in one purification tank 70A.

[0127] As described above, the organic solvent recovery unit 5t includes multiple recovery tanks 60A, 60B, and therefore, by switching between the recovery tanks 60A, 60B as the liquid destination, it is possible to continuously transfer the liquid collected in the cup 42 (i.e., the water supplied to the substrate W and then recovered, and the organic solvent supplied to the substrate W and then recovered). Furthermore, since the organic solvent recovery unit 5t includes multiple purification tanks 70A, 70B, it is possible to continuously transfer the concentrated fluid obtained by separating water from the mixed fluid by switching between the purification tanks 70A, 70B as the liquid destination. This shortens the cycle time from when the organic solvent supplied to the substrate W is recovered until it is again supplied to the substrate W. As a result, it is possible to effectively reduce the amount of organic solvent used and discharged.

[0128] <5-2. Second modified example> In the organic solvent recovery unit 5 according to the embodiment described above, a gas supply unit 60u may be provided in the first piping portion 62a or the bypass piping portion 62c (FIG. 17). Specifically, the gas supply unit 60u may include, for example, a gas supply source 601u that supplies a predetermined gas (such as nitrogen gas, an inert gas, or air), a pipe 602u that connects the gas supply source 601u to the first piping portion 62a or the bypass piping portion 62c (the first piping portion 62a in the illustrated example), and a valve 603u provided on the pipe 602u. As described above, in the second circulation state X2 in which the mixed fluid circulates through the first piping portion 62a and the bypass piping portion 62c, water contained in the mixed fluid is separated in the dehydrator 621. During this time, gas is supplied from the gas supply unit 60u to the first piping portion 62a and the bypass piping portion 62c to compensate for the drop in pressure in the piping caused by the separation of water. This maintains the pressure in the first piping section 62a and the bypass piping section 62c. When the gas supply unit 60u is provided, the buffer tank 60s may be omitted.

[0129] <5-3.Third modified example> In the organic solvent recovery section 5 according to the above embodiment, the dehydrator 621 may be disposed in an attitude and orientation such that the cells 512 extend in the vertical direction and the inlets 521 are disposed vertically below (and therefore the first outlets 522 are disposed vertically above). In this case, the mixed fluid flowing through the dehydration circulation pipe 62 flows into the cells 512 from the openings on the vertically lower side.

[0130] According to this modification, the mixed fluid that has flowed into the cell 512 from the dehydration circulation pipe 62 flows from bottom to top inside the cell 512 (intra-cell space V1), which extends vertically. Therefore, the mixed fluid that has flowed into the intra-cell space V1 (particularly, the liquid IPA and liquid water contained in the mixed fluid) remains sufficiently in the intra-cell space V1 due to gravity and comes into sufficient contact with the separation membrane 51. This increases the likelihood that the water contained in the mixed fluid will be separated. In other words, separation efficiency is further improved.

[0131] <5-4. Fourth Variation> In the organic solvent recovery unit 5 according to the above embodiment, if the first piping section 62a, the bypass piping section 62c, and the equipment attached thereto have the necessary pressure resistance, sufficient safety can be ensured even if the IPA contained in the mixed fluid boils. In this case, the heating temperature T2 may be equal to or higher than the pressurized boiling point T3. For example, the heating temperature T2 may be equal to or higher than the boiling point of water under separation pressure P2. When the heating temperature T2 is equal to or higher than the boiling point of water under separation pressure P2, the mixed fluid flowing into the dehydrator 621 is in a vapor state (i.e., both the water and IPA contained in the mixed fluid are in a vapor state). Compared to liquid water, vapor water (water vapor) has a larger intermolecular distance, a smaller intermolecular force, and a higher average molecular kinetic energy, making it easier to pass through the separation membrane 51. Therefore, the separation efficiency is improved when the water contained in the mixed fluid flowing into the dehydrator 621 is in a vapor state. The method of supplying the fluid to be separated in a vapor state to the separation membrane 51 is also called the VP (vapor permeation) method.

[0132] Even if the heating temperature T2 is lower than the boiling point of water under the separation pressure P2, some of the water contained in the mixed fluid heated to the heating temperature T2 will be converted into water vapor, and the presence of this water vapor will increase the separation efficiency.

[0133] <5-5. Other variations> In the organic solvent recovery section 5 according to the above embodiment, the dehydrator 621 is provided in the first piping section 62a, but the dehydrator 621 may be provided in the bypass piping section 62c. Furthermore, the recovery tank 60 is provided in the second piping section 62b, but the recovery tank 60 may be provided, for example, in the first piping section 62a. In this case, the recovery tank 60 has pressure resistance capable of withstanding the separation pressure P2 and heat resistance capable of withstanding the heating temperature T2. For example, the recovery tank 60 in this case is formed by a pressure vessel (pressure tank).

[0134] In the above embodiment, the first position Q1 and the second position Q2 can be set at any positions along the dehydration circulation pipe 62.

[0135] In the organic solvent recovery section 5 according to the above embodiment, the pressurized and heated mixed fluid does not flow through the separation pipe 53 and the drainage pipe 54. Therefore, the separation pipe 53, the drainage pipe 54, and the equipment provided therein (e.g., the vacuum pump 531, the condenser 532, and the decomposer 541) do not need to have the pressure resistance to withstand the separation pressure P2 or the heat resistance to withstand the heating temperature T2. In other words, the separation pipe 53, the drainage pipe 54, and the equipment provided therein may have lower pressure resistance and heat resistance than the first piping portion 62a, etc. As an example, the separation pipe 53 and the drainage pipe 54 are formed of resin piping.

[0136] In the organic solvent recovery section 5 according to the above embodiment, a cooler may be provided in the first piping section 62a or the bypass piping section 62c. Alternatively, a temperature regulator having a function as a cooler in addition to a function as the heater 623 (i.e., a temperature regulator having cooling and heating capabilities) may be provided. In these cases, for example, after the concentrated fluid is obtained in the first piping section 62a and the bypass piping section 62c and heating of the concentrated fluid is stopped (step S208), the concentrated fluid can be cooled by the cooler or the temperature regulator to quickly lower the temperature of the concentrated fluid to a temperature lower than the reference boiling point T1.

[0137] In the organic solvent recovery unit 5 according to the above embodiment, the configuration of the dehydrator 621 can be modified as appropriate. For example, the separation membrane 51 included in the dehydrator 621 is not limited to a zeolite membrane. For example, the separation membrane 51 may be an organic separation membrane. The organic separation membrane is an organic membrane formed, for example, of polyvinyl alcohol, chitosan, polyimide, or the like. Alternatively, the separation membrane 51 may be a CNT (carbon nanotube) separation membrane. The CNT separation membrane is a membrane obtained by adding carbon nanotubes to a membrane such as polyamide. Alternatively, the separation membrane 51 may be formed of a two-dimensional material. The two-dimensional material is a material composed of one atomic layer, and specific examples include molybdenum sulfide (MoS2) and a composite atomic layer compound of an early transition metal (titanium, vanadium, etc.) and a light element (carbon or nitrogen). Alternatively, separation membrane 51 may be formed from a MOF (Metal Organic Frameworks) material, or may be formed from a carbon material (for example, graphene, graphene oxide, etc.).

[0138] In the substrate processing apparatus 100 according to the above embodiment, the processing units 4 from which the organic solvent recovery section 5 recovers and supplies the organic solvent do not necessarily have to be all processing units 4 included in the same tower. That is, the organic solvent recovery section 5 may recover and supply the organic solvent to one or more arbitrarily selected processing units 4. Furthermore, the processing unit 4 from which the organic solvent recovery section 5 recovers the organic solvent may be different from the processing unit 4 from which the organic solvent is supplied.

[0139] In the substrate processing apparatus 100 according to the above embodiment, the organic solvent is not limited to IPA. For example, the organic solvent may be at least one of HFE (hydrofluoroether), methanol, ethanol, acetone, and trans-1,2-dichloroethylene. Furthermore, the organic solvent does not need to be composed of a single component, and may be a liquid mixture of multiple components.

[0140] In the substrate processing apparatus 100 according to the above embodiment, the rinse liquid may be any of various liquids including water. For example, the rinse liquid may be any of carbonated water, electrolytic ion water, hydrogen water, ozone water, and diluted hydrochloric acid water (e.g., about 10 to 100 ppm).

[0141] In the substrate processing apparatus 100 according to each of the above embodiments, the substrate W to be processed does not necessarily have to be a semiconductor substrate. For example, the substrate W to be processed may be a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, etc. Furthermore, the substrate W to be processed does not have to be perfectly circular, and may have a shape such as a notch, an orientation flat, etc.

[0142] Although the substrate processing apparatus and the substrate processing method have been described in detail above, the above description is merely illustrative in all respects and does not limit the substrate processing apparatus and the substrate processing method. It is understood that countless variations not illustrated can be envisioned without departing from the scope of this disclosure. The configurations described in the above embodiments and variations can be combined or omitted as appropriate, as long as they are not mutually inconsistent. [Explanation of symbols]

[0143] 100 Substrate processing apparatus 4 Processing Unit 43c Organic solvent nozzle 43b Rinse liquid nozzle 5. Organic solvent recovery section 60 Recovery Tank 61 Recovery piping 62 Circulation piping (circulation piping for dehydration) 62a 1st piping section 62b 2nd piping section 62c Bypass piping section 621 Dehydrator 51 Separation membrane 622 Pump (Dehydration side liquid transfer pump) 623 Heater 60s buffer tank 70 Purification Tank 71 First liquid supply pipe 72 Purification circulation piping 721 Purification side liquid transfer pump 723 Filter 80 Supply Tank 81 Second liquid supply pipe

Claims

1. a rinse liquid supply unit that supplies a rinse liquid containing water to the substrate; an organic solvent supply unit that supplies an organic solvent to the substrate; a recovery tank configured to store a mixed fluid containing the water supplied to the substrate and then recovered, and the organic solvent supplied to the substrate and then recovered; a circulation pipe connected to the recovery tank; a dehydrator provided in the circulation pipe and including a separation membrane that allows the water to pass through but does not allow the organic solvent to pass through; a pump provided in the circulation pipe; a heater provided in the circulation pipe; Equipped with a first position and a second position are defined in the circulation piping, and the circulation piping includes: a first piping section connecting a downstream side of the second position with an upstream side of the first position; a second piping section connecting a downstream side of the first position with an upstream side of the second position; and a bypass piping section connecting the downstream side of the first position with an upstream side of the second position via a route different from that of the second piping section; the dehydrator is provided in the first piping section or the bypass piping section, In a state in which the mixed fluid is circulating through the first piping portion and the bypass piping portion, the pump pressurizes the mixed fluid to a separation pressure higher than a circulation pressure required for circulation, and the heater heats the mixed fluid to a predetermined heating temperature. Substrate processing equipment.

2. The substrate processing apparatus according to claim 1 , The recovery tank is provided in the second piping section. Substrate processing equipment.

3. 3. The substrate processing apparatus according to claim 1, the heating temperature is higher than the boiling point of the organic solvent under atmospheric pressure and lower than the boiling point of the organic solvent under the dissociation pressure; Substrate processing equipment.

4. 4. The substrate processing apparatus according to claim 3, In a state in which the mixed fluid is circulating through the first piping portion and the bypass piping portion, the pump pressurizes the mixed fluid to the separation pressure, and then the heater heats the mixed fluid to the heating temperature. Substrate processing equipment.

5. 4. The substrate processing apparatus according to claim 3, in a state in which a concentrated fluid obtained by separating the water from the mixed fluid is circulating through the first piping portion and the bypass piping portion, the heater stops heating, and after the temperature of the concentrated fluid becomes lower than the boiling point of the organic solvent under atmospheric pressure, the pump stops pressurizing the concentrated fluid. Substrate processing equipment.

6. 3. The substrate processing apparatus according to claim 1, a vacuum pump that reduces the pressure of a space in the dehydrator into which water that has passed through the separation membrane flows; Equipped with Substrate processing equipment.

7. 3. The substrate processing apparatus according to claim 1, a purification tank connected to the recovery tank via the circulation pipe and the liquid transfer pipe, and configured to store a concentrated fluid obtained by separating the water from the mixed fluid; a filter provided in a pipe connected to the purification tank, for capturing substances to be removed that are contained in the concentrated fluid flowing through the pipe; Equipped with Substrate processing equipment.

8. 8. The substrate processing apparatus according to claim 7, the concentrated fluid stored in the purification tank is passed through the filter, and then sent to the organic solvent supply unit and supplied to the substrate; Substrate processing equipment.

9. 3. The substrate processing apparatus according to claim 1, the circulation pipe includes a plurality of branch portions provided between a branch position downstream of the first position and a junction position upstream of the second position, The recovery tank is provided in each of the plurality of branch portions. Substrate processing equipment.

10. 3. The substrate processing apparatus according to claim 1, the dehydrator is disposed in an orientation such that cells serving as flow paths for the mixed fluid within the separation membrane extend in a vertical direction, the mixed fluid flowing through the circulation pipe flows into the cell from an opening on a vertically lower side thereof; Substrate processing equipment.

11. 3. The substrate processing apparatus according to claim 1, The heating temperature is equal to or higher than the boiling point of water under the dissociating pressure. Substrate processing equipment.

12. a rinse liquid supplying step of supplying a rinse liquid containing water to the substrate; an organic solvent supplying step of supplying an organic solvent to the substrate; a storing step of storing in a recovery tank a mixed fluid containing the water supplied to the substrate and then recovered, and the organic solvent supplied to the substrate and then recovered; a filling step of filling the mixed fluid stored in the recovery tank into a circulation pipe connected to the recovery tank; a circulating step of circulating the mixed fluid through the first piping section and the bypass piping section among a first piping section, a second piping section, and a bypass piping section included in the circulation piping; a pressurizing step of pressurizing the mixed fluid circulating through the first piping section and the bypass piping section to a separation pressure higher than a circulation pressure required for circulation; a heating step of heating the mixed fluid circulating through the first piping portion and the bypass piping portion to a predetermined heating temperature; a separation step of separating the water from the mixed fluid by introducing the mixed fluid circulating through the first piping portion and the bypass piping portion into a dehydrator having a separation membrane that allows the water to pass through but blocks the organic solvent; Equipped with a first position and a second position are defined in the circulation piping, the first piping section is a piping section that connects the downstream side of the second position with the upstream side of the first position, the second piping section is a piping section that connects the downstream side of the first position with the upstream side of the second position, and the bypass piping section is a piping section that connects the downstream side of the first position with the upstream side of the second position via a route different from that of the second piping section; Substrate processing method.

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