Substrate processing apparatus and substrate processing method

Abstract

To provide a technology capable of narrowing an explosion-proof area without impairing safety.SOLUTION: A substrate processing apparatus 100 includes: a recovery tank 60 that stores a mixed fluid including water recovered after being supplied to a substrate W and an organic solvent recovered after being supplied to the substrate W; a dehydrator 621 that is provided in a pipe 62 connected to the recovery tank 60 and includes a separation membrane 51 that allows water to pass therethrough and does not allow the organic solvent to pass therethrough; a separation pipe 53 that is connected to the dehydrator 621 and into which separated water that has passed through the separation membrane 51 flows; a monitoring concentration sensor 533 that measures a concentration of the organic solvent contained in the separated water; a shutoff valve 534 that is provided in the separation pipe 53 and shuts off a flow of the separated water through the separation pipe 53 in a closed state; and a control part 6 that closes the shutoff valve 534 when a concentration Dt of the organic solvent measured by the monitoring concentration sensor 533 exceeds a safe concentration Ds lower than a lower explosion limit concentration De of the organic solvent.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] When flammable substances such as IPA are handled, the area where the substance is handled is designated as an explosion-proof area. Electrical equipment (equipment that could become an ignition source) placed within the explosion-proof area must be explosion-proof to prevent it from becoming an ignition source. Naturally, the larger the explosion-proof area, the greater the number of pieces of equipment that must be explosion-proof.

[0005] Therefore, an object of the present disclosure is to provide a technique that can narrow the explosion-proof area without compromising safety. [Means for solving the problem]

[0006] a recovery tank for storing a mixed fluid containing the water supplied to the substrate and then recovered, a dehydrator provided in a pipe connected to the recovery tank and having a separation membrane that allows the water to pass but not the organic solvent, a separation pipe connected to the dehydrator and into which separated water that has passed through the separation membrane flows, a monitoring concentration sensor for measuring the concentration of the organic solvent contained in the separated water, a shutoff valve provided in the separation pipe and, when in a closed state, shutting off the flow of the separated water through the separation pipe, and a control unit for closing the shutoff valve when the concentration of the organic solvent measured by the monitoring concentration sensor exceeds a safe concentration that is lower than the lower explosion limit concentration of the organic solvent.

[0007] A second aspect is a substrate processing apparatus according to the first aspect, comprising a condenser provided downstream of the shut-off valve in the separation pipe for condensing the separated water, and a drainage pipe for conducting the separated water condensed by the condenser.

[0008] A third aspect is a substrate processing apparatus according to the second aspect, further comprising a water stop valve provided in the drainage pipe that, when closed, blocks the flow of the separated water through the drainage pipe, and the control unit closes the water stop valve when the concentration of the organic solvent measured by the monitoring concentration sensor exceeds the safe concentration.

[0009] A fourth aspect is a substrate processing apparatus according to the second aspect, comprising: a return pipe connecting a branch position defined midway along the drainage pipe to the recovery tank; and a flow path switching valve provided at the branch position and switchable between a first state in which the separated water flowing from the upstream side of the drainage pipe is caused to flow into the downstream side of the drainage pipe without flowing into the return pipe, and a second state in which the separated water flowing from the upstream side of the drainage pipe is caused to flow into the return pipe, and the control unit switches the flow path switching valve from the first state to the second state when the concentration of the organic solvent measured by the monitoring concentration sensor exceeds the safe concentration.

[0010] A fifth aspect is the substrate processing apparatus according to any one of the second to fourth aspects, further comprising a decomposer that decomposes the organic solvent contained in the separated water flowing through the drainage pipe.

[0011] A sixth aspect is the substrate processing apparatus according to any one of the second to fifth aspects, wherein the separated water is guided to the rinse liquid supply unit through the drainage pipe and supplied to the substrate as the rinse liquid.

[0012] A seventh aspect is a substrate processing apparatus according to any one of the first to sixth aspects, comprising a housing that houses the recovery tank, the piping, and the dehydrator, and the separation piping is provided to pass through the housing.

[0013] an organic solvent supplying step of supplying an organic solvent to the substrate; a storage step of storing in a recovery tank a mixed fluid containing the water supplied to the substrate and recovered therefrom and the organic solvent supplied to the substrate and recovered therefrom; a flowing step of flowing the mixed fluid stored in the recovery tank through a pipe provided with a dehydrator having a separation membrane that allows the water to pass through but not the organic solvent; a separation step of flowing separated water separated from the mixed fluid that has flowed into the dehydrator into a separation pipe; a monitoring step of determining whether the concentration of the organic solvent contained in the separated water flowing through the separation pipe exceeds a safe concentration that is lower than the lower explosion limit of the organic solvent; and a shutoff step of shutting off the flow of the separated water through the separation pipe when it is determined that the concentration of the organic solvent has exceeded the safe concentration. [Effects of the Invention]

[0014] According to each of the first and eighth aspects, if the concentration of the organic solvent contained in the separated water exceeds a safe concentration that is lower than the lower explosion limit due to some abnormality, the shutoff valve is closed. Therefore, it is possible to prevent separated water containing organic solvents at a concentration that exceeds the lower explosion limit from flowing downstream of the shutoff valve. Therefore, even if the area downstream of the shutoff valve is designated as a non-explosion-proof area (i.e., even if the equipment installed downstream of the shutoff valve does not have to be explosion-proof), safety is guaranteed. In other words, the explosion-proof area can be narrowed without compromising safety.

[0015] According to the second aspect, the separated water that flows into the separation pipe can be condensed and led to the drainage pipe. In addition, since the condenser is provided downstream of the shut-off valve, explosion-proofing is not required for the devices provided in the condenser and the drainage pipe.

[0016] According to the third aspect, even if separated water containing an organic solvent at a concentration that does not exceed the lower explosion limit but slightly exceeds the safety concentration flows out downstream of the shut-off valve, such separated water can be prevented from flowing out downstream of the stop valve.

[0017] According to the fourth aspect, even if separated water containing an organic solvent at a concentration that does not exceed the lower explosion limit but slightly exceeds the safety concentration flows out downstream of the shut-off valve, such separated water can be returned to the recovery tank without flowing out downstream of the flow path switching valve.

[0018] According to the fifth aspect, even if the separated water that flows into the drainage pipe contains a trace amount of organic solvent, the organic solvent content in the separated water can be sufficiently reduced by decomposing the organic solvent. Moreover, since the decomposer is installed downstream of the shutoff valve, the decomposer does not need to be explosion-proof.

[0019] According to the sixth aspect, separated 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 as a rinse liquid, thereby reducing the amount of water used.

[0020] According to the seventh aspect, even if an organic solvent leaks out of the housing due to an unexpected event, the organic solvent can be contained within the housing. [Brief explanation of the drawings]

[0021] [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 the flow of a process for separating water from a mixed fluid and a process for monitoring the concentration of IPA contained in the separated water. [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 S213a and step S213b. [Figure 11] FIG. 10 is a diagram for explaining step S205. [Figure 12] FIG. 10 is a diagram for explaining step S3. [Figure 13] FIG. 10 is a diagram for explaining step S4. [Figure 14] FIG. 10 is a diagram schematically illustrating a configuration example of an organic solvent recovery unit according to a modified example. [Figure 15] 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

[0022] 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.

[0023] 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.

[0024] <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.

[0025] 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.

[0026] 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.

[0027] 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.).

[0028] 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.

[0029] 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).

[0030] 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.

[0031] 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.

[0032] 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.

[0033] <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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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)).

[0040] 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).

[0041] 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.

[0042] <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.

[0043] 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.

[0044] 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.

[0045] 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).

[0046] 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).

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] <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.

[0052] 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).

[0053] (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.

[0054] 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.

[0055] 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.

[0056] The dehydration circulation pipe 62 is provided with a pump (spin-off liquid pump) 622, a heater 623, and a pair of on-off valves 624a, 624b. As an example, the spin-off liquid pump 622 is provided downstream of the recovery tank 60 and upstream of the dehydrator 621, and the heater 623 is provided downstream of the spin-off liquid pump 622 and upstream of the dehydrator 621. One on-off valve 624a is provided upstream of the recovery tank 60, and the other on-off valve 624b is provided downstream of the recovery tank 60. The spin-off liquid pump 622 sends the mixed fluid in the dehydration circulation pipe 62 at a pressure required for circulation (circulation pressure). With both of the pair of on-off valves 624a, 624b open, the dehydration-side liquid supply pump 622 supplies the mixed fluid at circulation pressure, causing the mixed fluid stored in the recovery tank 60 to circulate through the dehydration circulation pipe 62. The heater 623 heats the mixed fluid circulating through the dehydration circulation pipe 62 to a predetermined temperature.

[0057] 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, and the like. In the illustrated example, the concentration sensor 625 is provided near the upstream side of the recovery tank 60, the pressure sensor 626 is provided near the downstream side of the dehydration-side liquid feed pump 622, the temperature sensor 627 is provided near the downstream side of the heater 623, and the flow rate sensor 628 is provided near the upstream side of the dehydration-side liquid feed pump 622.

[0058] (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.

[0059] The dehydrator 621 includes a separation membrane 51 and a housing 52 .

[0060] 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.

[0061] 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.

[0062] 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.

[0063] (c) Configuration of the separation pipe 53 side Next, the configuration of separation pipe 53 into which water that has passed through separation membrane 51 (hereinafter also referred to as "separated water") flows will be described with reference to FIG.

[0064] A condenser 532 that condenses the separated water is provided in the separation pipe 53 upstream of the vacuum pump 531. The condenser 532 is connected to the drain pipe 54 that guides the separated water condensed therein. As described above, the mixed fluid circulating through the dehydration circulation pipe 62 is heated by the heater 623. Therefore, at least a portion of the mixed fluid circulating through the dehydration circulation pipe 62 (i.e., the mixed fluid flowing into the dehydrator 621) is in a vapor state, and at least a portion of the separated water that passes through the separation membrane 51 and flows into the separation pipe 53 is also in a vapor state. The condenser 532 condenses the separated water that has flowed into the separation pipe 53 in a vapor state, and causes it to flow into the drain pipe 54. As an example, the condenser 532 may be formed using a device (a so-called heat exchanger) that circulates a cooling medium (e.g., cooling water) through a cooling pipe provided around the pipe to remove heat from the fluid flowing through the pipe and cool it. Needless to say, not only separated water that flows into the separation pipe 53 in a vapor state and is condensed in the condenser 532 flows into the drain pipe 54, but also separated water that has flowed into the separation pipe 53 in a liquid state from the beginning.

[0065] The drainage pipe 54 is provided with a decomposer 541 that decomposes an organic solvent (IPA in this case) contained in the separated water flowing therethrough. Although the separation membrane 51 is a membrane that allows water to pass through but not IPA, in reality, it is inevitable that a trace amount of IPA will pass through the separation membrane 51. For this reason, even if the separation membrane 51 is in a normal state, the separated water flowing into the separation pipe 53 may contain a trace amount of IPA. Therefore, the decomposer 541 decomposes the trace amount of IPA contained in the separated water. By decomposing the IPA, the IPA content in the separated water can be sufficiently reduced. Furthermore, if the IPA contained in the separated water is decomposed into, for example, water and carbon dioxide, the water content (purity) of the separated water can be increased. As an example, the decomposer 541 may electrolyze the IPA contained in the separated water. In this case, the decomposer 541 can be configured to include, for example, a tank for temporarily storing the separated water flowing through the drainage pipe 54, a pair of electrodes immersed in the separated 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.

[0066] The drain pipe 54 is connected to, for example, a rinse liquid supply source 433b of the processing unit 4 (FIG. 2). In this case, the separated water that flows into the drain pipe 54 has IPA contained therein decomposed in a decomposer 541, and then is guided to the rinse liquid supply source 433b and discharged from the rinse liquid nozzle 43b as a rinse liquid. That is, in this case, the separated water is reused as a rinse liquid. However, the drain pipe 54 does not necessarily have to be connected to the rinse liquid supply source 433b, and may be connected, for example, to a water recovery line of the factory. In this case, the separated water that flows into the drain pipe 54 has IPA contained therein decomposed in the decomposer 541, and then is guided to the water recovery line of the factory and recovered.

[0067] Separation pipe 53 is provided with a concentration sensor (monitoring concentration sensor) 533 that measures the concentration of an organic solvent (IPA in this case) contained in the separated water flowing therethrough. As described above, separation membrane 51 is a membrane that allows water to pass through but does not allow IPA to pass through. Therefore, unless there is any abnormality, the amount of IPA contained in the separated water that passes through separation membrane 51 and flows into separation pipe 53 should be sufficiently small (i.e., the concentration of IPA contained in the separated water should be sufficiently low). However, there is a possibility that some abnormality (e.g., an abnormality in separation membrane 51) may occur, causing the concentration of IPA in the separated water to increase. Therefore, here, monitoring concentration sensor 533 measures the concentration of IPA contained in the separated water flowing through separation pipe 53. As an example, monitoring concentration sensor 533 is provided near the upstream end of separation pipe 53. The monitoring concentration sensor 533 is connected (e.g., electrically connected) to the control unit 6, and in response to instructions from the control unit 6, measures the concentration of IPA contained in the separation water flowing through the separation pipe 53 and outputs the obtained measurement value (measured concentration) Dt to the control unit 6.

[0068] The separation pipe 53 is further provided with a valve (shutoff valve) 534 that switches between allowing and blocking the flow of separated water through the separation pipe 53. That is, when the shutoff valve 534 is open, the separated water can flow downstream of the shutoff valve 534, and when the shutoff valve 534 is closed, the separated water is blocked from flowing out downstream of the shutoff valve 534. As an example, the shutoff valve 534 is provided downstream of the monitoring concentration sensor 533 and upstream of the condenser 532. The shutoff valve 534 is connected (e.g., electrically connected) to the control unit 6, and is opened and closed in response to instructions from the control unit 6. That is, the opening and closing timing of the shutoff valve 534 is controlled by the control unit 6.

[0069] Meanwhile, the drain pipe 54 is also provided with a valve (stop valve) 542 that switches between allowing and blocking the flow of separated water through the drain pipe 54. That is, when the stop valve 542 is open, the separated water can flow downstream of the stop valve 542, and when the stop valve 542 is closed, the separated water is blocked so as not to flow out downstream of the stop valve 542. As an example, the stop valve 542 is provided downstream of the decomposer 541. The stop valve 542 is connected (for example, electrically connected) to the control unit 6, and is opened and closed in response to instructions from the control unit 6. That is, the opening and closing timing of the stop valve 542 is controlled by the control unit 6.

[0070] The control unit 6 determines (monitors) whether the measured concentration Dt acquired by the monitoring concentration sensor 533 exceeds a predetermined safe concentration Ds. When it is determined that the measured concentration Dt exceeds the safe concentration Ds (becomes higher than the safe concentration Ds), the control unit 6 closes both the shut-off valve 534 and the water stop valve 542. When the shut-off valve 534 is closed, the flow of separated water through the separation pipe 53 is blocked, and when the water stop valve 542 is closed, the flow of separated water through the drain pipe 54 is also blocked. However, the safe concentration Ds is a value lower than the lower explosion limit concentration (LEL: Lower Explosion Limit) De of the organic solvent (here IPA) (Ds < De). The safe concentration Ds is, for example, set to 25% or less of the lower explosion limit concentration De (that is, 25% LEL or less). As an example, the safe concentration Ds is set to 25% (25% LEL) of the lower explosion limit concentration De.

[0071] In this way, here, when the measured concentration Dt acquired by the monitoring concentration sensor 533 exceeds the safe concentration Ds, the shut-off valve 534 is closed and the flow of separated water through the separation pipe 53 is blocked. That is, here, even when the concentration of IPA contained in the separated water increases due to some abnormality, the shut-off valve 534 is closed at a stage before this reaches the lower explosion limit concentration De. Therefore, it is possible to prevent the outflow of separated water (hereinafter also referred to as "dangerous separated water") containing IPA at a concentration exceeding the lower explosion limit concentration De to the downstream side of the shut-off valve 534.

[0072] On the other hand, because monitoring concentration sensor 533 is expected to have a predetermined response time, there is a non-zero possibility that, when shutoff valve 534 is closed, separated water containing IPA at a concentration that does not exceed the lower explosive limit concentration De but slightly exceeds the safe concentration Ds (hereinafter also referred to as "abnormal separated water") may be flowing downstream of shutoff valve 534. However, in this case, when the measured concentration Dt exceeds the safe concentration Ds, stop valve 542 is closed, and the flow of separated water through drainage piping 54 is blocked. Therefore, even if abnormal separated water has flowed downstream of shutoff valve 534, the abnormal separated water is prevented from flowing downstream of stop valve 542. Therefore, the abnormal separated water does not flow into rinse liquid supply source 433b, the plant's water recovery line, etc.

[0073] (d) Purification tank 70 The purification tank 70 is connected to the recovery tank 60 via a first liquid supply pipe 71 and a 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 a position in the dehydration circulation pipe 62 that is upstream of the dehydrator 621 and downstream of the heater 623. However, the other end of the first liquid supply pipe 71 may be connected directly to the recovery tank 60 without going through the dehydration circulation pipe 62. A first liquid supply valve 711 is provided in the first liquid supply pipe 71. When the recovery tank 60 contains a fluid (hereinafter referred to as "concentrated fluid") in which the concentration (purity) of IPA has been sufficiently increased (enough to be supplied to the substrate W) by separating water from the mixed fluid, and the first liquid supply valve 711 is opened, the concentrated fluid is guided to the first liquid supply pipe 71 and flows into the purification tank 70, where it is stored.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] (e) 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] <3-2. Explosion-proof area> Here, the area where IPA is handled is defined as the explosion-proof area A1. Electrical equipment and the like used within the explosion-proof area A1 (equipment that may become an ignition source (burn)) is explosion-proofed to prevent it from becoming an ignition source. Explosion-proofing can be implemented using an appropriate method in accordance with established standards. For example, explosion-proofing can be implemented by housing the equipment in question in a container and filling (purging) the container with an inert gas (e.g., nitrogen gas). Alternatively, explosion-proofing can be implemented by applying specifications (explosion-proof specifications) to the current-carrying parts of the equipment in question that make it difficult for sparks to occur.

[0083] The mixed fluid contains a large amount of IPA. Therefore, the area where recovery tank 60 storing the mixed fluid and the piping through which the mixed fluid flows (recovery piping 61 and dehydration circulation piping 62) are located is designated as explosion-proof area A1. That is, the electrical equipment (e.g., dehydration-side liquid supply pump 622, heater 623, sensors (e.g., concentration sensor 625, pressure sensor 626, temperature sensor 627, flow rate sensor 628)) provided in dehydration circulation piping 62 is explosion-proof. Furthermore, the valves (e.g., recovery valve 611, on-off valves 624a, 624b) provided in recovery piping 61 and dehydration circulation piping 62 do not require explosion-proofing if they are driven by air, but explosion-proofing is required if they are driven by electricity. As described above, explosion-proofing can be implemented by any appropriate method. For example, a container K may be provided to house each of the target devices individually, and each container K may be filled with an inert gas to provide explosion protection.

[0084] The concentrated fluid also contains a large amount of IPA. Therefore, the area where the purification tank 70 storing the concentrated fluid and the piping through which the concentrated fluid circulates (first liquid feed piping 71 and purification circulation piping 72) are located is also designated as explosion-proof area A1. That is, the electrical equipment provided in the purification circulation piping 72 (e.g., the purification-side liquid feed pump 721, the temperature regulator 724, and sensors (e.g., the pressure sensor 725 and the temperature sensor 726)) is explosion-proof. Furthermore, the valves provided in the first liquid feed piping 71 and the purification circulation piping 72 (e.g., the first liquid feed valve 711 and the on-off valve 722) are explosion-proof if they are powered by electricity.

[0085] On the other hand, as described above, the separated water normally (if there is no abnormality) contains only a trace amount of IPA. However, there is a possibility that the concentration of IPA in the separated water may increase due to some abnormality. However, as described above, in such a case, it is ensured that separated water containing IPA at a concentration exceeding the lower explosion limit concentration De (hazardous separated water) does not flow downstream of the shutoff valve 534 provided in the separation pipe 53. For this reason, the area downstream of the shutoff valve 534 can be designated as a non-explosion-proof area A2.

[0086] Here, for example, the area where the piping section (downstream piping section) 53a downstream of the shutoff valve 534 in the separation piping 53 is located is defined as the non-explosion-proof area A2. That is, the electrical equipment (e.g., vacuum pump 531, condenser 532) provided in the downstream piping section 53a is not explosion-proof. For example, even if the condenser 532 has a flow sensor that measures the flow rate of the cooling water used for condensation, the flow sensor is not explosion-proof.

[0087] Furthermore, the area where the drainage pipe 54 through which the separated water condensed in the condenser 532 flows is arranged is also considered to be non-explosion-proof area A2. That is, the electrical equipment (e.g., decomposer 541) provided in the drainage pipe 54 is not explosion-proof. Furthermore, the valves (e.g., stop valve 542) provided in the drainage pipe 54 are not explosion-proof even if they are powered by electricity.

[0088] In the illustrated example, the area where a piping section (upstream piping section) 53b upstream of downstream piping section 53a in separation piping 53 is disposed is designated as explosion-proof area A1. That is, electrical equipment (e.g., monitoring concentration sensor 533) provided in upstream piping section 53b is explosion-proof. Furthermore, valves (e.g., shut-off valve 534) provided in upstream piping section 53b are explosion-proof if they are powered by electricity.

[0089] However, the area where the upstream piping section 53b is located may be designated as a non-explosion-proof area A2. That is, electrical equipment (e.g., monitoring concentration sensor 533) provided in the upstream piping section 53b may not be explosion-proof. Furthermore, valves (e.g., shutoff valve 534) provided in the upstream piping section 53b may not be explosion-proof, even if they are powered by electricity. The reason why the area where the upstream piping section 53b is located may be designated as a non-explosion-proof area A2 is as follows. First, as described above, the shutoff valve 534 is closed when the measured concentration Dt exceeds the safe concentration Ds, which is lower than the lower explosion limit concentration De. Even if some abnormality occurs in the separation membrane 51 or the like, the concentration of IPA contained in the separated water is highly unlikely to increase rapidly. Therefore, it is highly unlikely that hazardous separated water has flowed into the upstream piping section 53b when the shutoff valve 534 is closed. Second, when shutoff valve 534 is closed, separation space V2 is isolated from vacuum pump 531, so the inflow of separated water into separation pipe 53 is essentially stopped. Therefore, the possibility of hazardous separated water flowing into upstream pipe section 53b after shutoff valve 534 is closed is extremely low. In this way, by closing shutoff valve 534 at a stage when measured concentration Dt exceeds safe concentration Ds, not only is hazardous separated water prevented from flowing out into downstream pipe section 53a, but also hazardous separated water is prevented from flowing into upstream pipe section 53b. Therefore, not only the area where downstream pipe section 53a is located but also the area where upstream pipe section 53b is located (i.e., the area where the entire separation pipe 53 is located) can be designated as non-explosion-proof area A2.

[0090] <3-3. Operation> The flow of processing carried out in the organic solvent recovery unit 5 will be described with reference to Figs. 5 to 13. Fig. 5 is a diagram showing an example of the flow of processing carried out in the organic solvent recovery unit 5. Fig. 6 is a diagram showing an example of the flow of processing for separating water from a mixed fluid and for monitoring the concentration of IPA contained in the separated water. Figs. 7 to 13 are diagrams schematically showing the state of the organic solvent recovery unit 5 in each step. For ease of explanation, in Figs. 7 to 13, pipes through which a fluid flows are indicated by solid lines, and pipes through which no fluid flows are indicated by 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 (monitoring concentration sensor 533, 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 (shutoff valve 534, water stop valve 542, recovery valve 611, a pair of on-off 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 progresses.

[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. In parallel with this process, a process is performed to monitor the concentration of IPA contained in the separated water. These processes will be specifically described with reference to Fig. 6 and Figs. 8 to 11.

[0094] (i) Separating water from a mixed fluid The process of separating water from the mixed fluid stored in the recovery tank 60 is carried out, for example, as follows.

[0095] First, the pair of on-off valves 624a, 624b are both opened, and the dehydration-side liquid-sending pump 622 sends the mixed fluid at circulation pressure. As a result, the mixed fluid stored in the recovery tank 60 flows through the dehydration circulation pipe 62 and circulates therethrough (step S201: circulation step) (FIG. 8). At this stage, the heater 623 heats the mixed fluid circulating through the dehydration circulation pipe 62 to a predetermined temperature.

[0096] Subsequently, the vacuum pump 531 starts to operate. By operating the vacuum pump 531, the pressure in the separation space V2 is reduced, and a pressure difference is created between the intra-cell space V1 and the separation space V2. This pressure difference causes the 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 pipe 53. That is, when the mixed fluid circulating through the dehydration circulation pipe 62 passes through the dehydrator 621, the water contained in the mixed fluid is separated and flows into the separation pipe 53 (step S202: separation step) (FIG. 9).

[0097] Thereafter, the vacuum pump 531 continues to operate for a predetermined time. During this time, the fluid mixture circulating through the dehydration circulation pipe 62 repeatedly passes through the dehydrator 621, thereby increasing the concentration of IPA in the fluid mixture. Here, the time required for the concentration of IPA in the fluid mixture stored in the collection tank 60 to increase sufficiently (enough to 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 specified as the predetermined time. Therefore, when the predetermined time has elapsed since the operation of the vacuum pump 531 was started, the concentrated fluid has been stored in the collection tank 60. When the predetermined time has elapsed since the operation of the vacuum pump 531 was started (YES in step S203), the operation of the vacuum pump 531 is stopped. This ends the separation of water in the dehydrator 621 (step S204).

[0098] Thereafter, the first liquid supply valve 711 is opened. Then, the concentrated fluid stored in the recovery tank 60 is sent to the purification tank 70 through the first liquid supply pipe 71. As a result, the concentrated fluid is stored in the purification tank 70 (step S205) (FIG. 11). When the entire amount of concentrated fluid stored in the recovery tank 60 has been sent to the purification tank 70, the first liquid supply valve 711 is closed.

[0099] (ii) Monitoring the concentration of IPA in the separated water The process of monitoring the concentration of IPA contained in the separated water is performed, for example, as follows.

[0100] When separation of water starts in the dehydrator 621, the separated water starts to flow into the separation pipe 53. For example, when separation of water starts in the dehydrator 621 (specifically, when the vacuum pump 531 starts operating), the control unit 6 starts monitoring the measured concentration Dt (step S211: monitoring step). Specifically, the control unit 6 causes the monitoring concentration sensor 533 to start measuring the concentration of IPA contained in the separated water flowing through the separation pipe 53. The monitoring concentration sensor 533 outputs the obtained measured concentration Dt to the control unit 6 in real time. The control unit 6 determines whether the measured concentrations Dt successively output in real time from the monitoring concentration sensor 533 exceed the safe concentration Ds.

[0101] If it is determined that the measured concentration Dt has exceeded the safe concentration Ds (become higher than the safe concentration Ds) (YES in step S212), the control unit 6 closes the shutoff valve 534 (step S213a: shutoff step) and also closes the water stop valve 542 (step S213b: water stop step). Closing the shutoff valve 534 blocks the flow of separated water through the separation pipe 53, and closing the water stop valve 542 blocks the flow of separated water through the drain pipe 54 (FIG. 10). As described above, if the measured concentration Dt exceeds the safe concentration Ds, there is a possibility that some abnormality has occurred in the separation membrane 51 or the like. Therefore, if it is determined that the measured concentration Dt exceeds the safe concentration Ds, it is preferable that the shut-off valve 534 and the water stop valve 542 are closed and the separation of water in the dehydrator 621 is stopped (specifically, for example, the operation of the vacuum pump 531, the dehydration side liquid supply pump 622, and the heater 623 is stopped and a pair of opening and closing valves 624a, 624b is closed).

[0102] On the other hand, if the separation of water in the dehydrator 621 is completed (specifically, if the operation of the vacuum pump 531 is stopped) without the measured concentration Dt output successively in real time from the monitoring concentration sensor 533 exceeding the safe concentration Ds, the control unit 6 ends monitoring of the measured concentration Dt (YES in step S214). If the separation of water in the dehydrator 621 is completed properly without being interrupted midway (step S204), the concentrated fluid stored in the recovery tank 60 is sent to the purification tank 70 (step S205), and then the process proceeds to step S3.

[0103] 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. 12 ). 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.

[0104] 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. 13). 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.

[0105] 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).

[0106] <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, and a dehydrator that is provided in a pipe (dehydration circulation pipe) 62 connected to the recovery tank 60 and has a separation membrane 51 that allows water to pass through but does not allow organic solvent to pass through. 621, a separation pipe 53 connected to the dehydrator 621 and into which separated water that has passed through the separation membrane 51 flows, a monitoring concentration sensor 533 that measures the concentration of the organic solvent contained in the separated water, a shut-off valve 534 that is provided in the separation pipe 53 and that, when in a closed state, shuts off the flow of the separated water through the separation pipe 53, and a control unit 6 that closes the shut-off valve 534 when the concentration (measured concentration) Dt of the organic solvent measured by the monitoring concentration sensor 533 exceeds a safety concentration Ds that is lower than the lower explosion limit concentration De of the organic solvent.

[0107] According to this configuration, if the concentration of the organic solvent contained in the separated water exceeds a safe concentration Ds, which is lower than the lower explosion limit concentration De, due to some abnormality, the shutoff valve 534 is closed. Therefore, it is possible to prevent separated water (hazardous separated water) containing an organic solvent at a concentration exceeding the lower explosion limit concentration De from flowing downstream of the shutoff valve 534. Therefore, even if the area downstream of the shutoff valve 534 is designated as a non-explosion-proof area A2 (i.e., even if the equipment installed downstream of the shutoff valve 534 does not require explosion protection), safety is ensured. In other words, the explosion-proof area A1 can be narrowed without compromising safety. Narrowing the explosion-proof area A1 makes it possible to reduce the number of equipment requiring explosion protection. This, for example, can reduce costs and make the device more compact.

[0108] Moreover, the substrate processing apparatus 100 according to the above embodiment includes a condenser 532 that is provided downstream of the shutoff valve 534 in the separation pipe 53 and condenses the separated water, and a drain pipe 54 that guides the separated water condensed by the condenser 532. With this configuration, the separated water that has flowed into the separation pipe 53 can be condensed and guided to the drain pipe 54. Furthermore, since the condenser 532 is provided downstream of the shutoff valve 534, devices provided in the condenser 532 and the drain pipe 54 are not required to be explosion-proof.

[0109] Furthermore, the substrate processing apparatus 100 according to the above embodiment includes a water stop valve 542 that is provided in the drain pipe 54 and that, when closed, blocks the flow of separated water through the drain pipe 54. The control unit 6 closes the water stop valve 542 when the measured concentration Dt exceeds the safe concentration Ds. With this configuration, even if separated water (abnormal separated water) containing an organic solvent at a concentration that does not exceed the lower explosion limit concentration De but slightly exceeds the safe concentration Ds flows out downstream of the shut-off valve 534, the separated water can be prevented from flowing out downstream of the water stop valve 542. In other words, the abnormal separated water can be prevented from flowing into the rinse liquid supply source 433b, the water recovery line of the factory, etc.

[0110] Furthermore, the substrate processing apparatus 100 according to the above embodiment includes a decomposer 541 that decomposes organic solvents contained in the separated water flowing through the drainage pipe 54. With this configuration, even if a trace amount of organic solvent is contained in the separated water that has flowed into the drainage pipe 54, the organic solvent can be decomposed, and the content of the organic solvent in the separated water can be sufficiently reduced. Furthermore, since the decomposer 541 is provided downstream of the shutoff valve 534, the decomposer 541 does not need to be explosion-proof.

[0111] Furthermore, in the above embodiment, the separated water is guided to the rinse liquid nozzle 43b through, for example, the drain pipe 54 and supplied as a rinse liquid to the substrate W. According to this configuration, the separated water separated from the mixed fluid containing the water supplied to the substrate W and then recovered and the organic solvent supplied to the substrate W and then recovered is supplied again as a rinse liquid to the substrate W. This makes it possible to reduce the amount of water used.

[0112] Moreover, the substrate processing apparatus 100 according to the above embodiment includes a purification tank 70 connected to the recovery tank 60 via a liquid transfer pipe (first liquid transfer pipe) 71 and storing a concentrated fluid obtained by separating water from the mixed fluid, and a filter 723 provided in a pipe (purification circulation pipe) 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 pipe 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> An organic solvent recovery section 5r according to a first modified example will be described with reference to Fig. 14. Fig. 14 is a diagram schematically showing an example of the organic solvent recovery section 5r.

[0116] The organic solvent recovery unit 5r includes a housing 50r that houses some or all of the equipment located in the explosion-proof area A1. The housing 50r has an airtight seal. Specifically, the housing 50r houses, for example, a recovery tank 60, a dehydration circulation pipe 62, and the equipment provided therein (a dehydrator 621, a dehydration-side liquid supply pump 622, a heater 623, on-off valves 624a and 624b, and sensors 625, 626, 627, and 628). The housing 50r also houses a purification tank 70, a first liquid supply pipe 71, a purification circulation pipe 72, and the equipment provided therein (a first liquid supply valve 711, a purification-side liquid supply pump 721, an on-off valve 722, a filter 723, a temperature regulator 724, and sensors 725 and 726). The recovery pipe 61, the separation pipe 53, and the second liquid supply pipe 81 are provided to penetrate the housing 50r. For example, the recovery pipe 61 has a downstream piping portion provided inside the housing 50r, penetrates the housing 50r partway, and an upstream piping portion provided outside the housing 50r. The separation pipe 53 has an upstream piping portion 53b provided inside the housing 50r, penetrates the housing 50r partway, and a downstream piping portion 53a provided outside the housing 50r. The second liquid supply pipe 81 has an upstream piping portion provided inside the housing 50r, penetrates the housing 50r partway, and a downstream piping portion provided outside the housing 50r. The portions of the housing 50r through which the recovery pipe 61, the separation pipe 53, or the second liquid supply pipe 81 penetrate are preferably airtightly sealed with a sealing member or the like.

[0117] According to this modification, even if an organic solvent (e.g., IPA) leaks out of the housing 50r due to an unexpected event, the IPA can be contained within the housing 50r. Therefore, even if such an unexpected event occurs, it is possible to prevent the IPA from leaking into the non-explosion-proof area A2, thereby improving safety. The housing 50r may be filled with an inert gas (e.g., nitrogen gas). The housing 50r may also be an explosion-proof container (a container strong enough to withstand an explosion).

[0118] <5-2. Second modified example> An organic solvent recovery section 5s according to a second modified example will be described with reference to Fig. 15. Fig. 15 is a diagram schematically showing an example of an organic solvent recovery section 5s.

[0119] In the organic solvent recovery unit 5s, similarly to the organic solvent recovery unit 5 according to the above embodiment, a monitoring concentration sensor 533 and a shutoff valve 534 are provided in the separation pipe 53. In addition, in the organic solvent recovery unit 5s, a return pipe 55 and a flow path switching valve 543 are provided in the drainage pipe 54.

[0120] The return pipe 55 connects a branch position R defined in the middle of the drainage pipe 54 to the recovery tank 60. That is, one end of the return pipe 55 is connected to the branch position R defined in the middle of the separation pipe 53, and the other end is connected to the recovery tank 60. As an example, the branch position R is defined downstream of the decomposer 541.

[0121] The flow path switching valve 543 is provided at the branch position R and is switchable between a first state in which the separated water flowing from the upstream side of the drainage pipe 54 is allowed to flow into the downstream side of the drainage pipe 54 without flowing into the return pipe 55, and a second state in which the separated water flowing from the upstream side of the drainage pipe 54 is allowed to flow into the return pipe 55. Specifically, the flow path switching valve 543 may be configured, for example, as a three-way valve, or may be configured to include multiple valves. The flow path switching valve 543 is connected (e.g., electrically connected) to the control unit 6 and is switched between the first state and the second state in response to an instruction from the control unit 6. That is, the state of the flow path switching valve 543 is controlled by the control unit 6.

[0122] The control unit 6 determines (monitors) whether the measured concentration Dt acquired by the monitoring concentration sensor 533 exceeds the safe concentration Ds. If it is determined that the measured concentration Dt exceeds the safe concentration Ds, the control unit 6 closes the shutoff valve 534 and switches the flow path switching valve 543 from the first state to the second state. Closing the shutoff valve 534 blocks the flow of separated water through the separation pipe 53. Furthermore, switching the flow path switching valve 543 from the first state to the second state causes the separated water in the drainage pipe 54 to be returned to the recovery tank 60 through the return pipe 55.

[0123] In this manner, once again, when the measured concentration Dt acquired by the monitoring concentration sensor 533 exceeds the safe concentration Ds, the shutoff valve 534 is closed, thereby preventing hazardous separated water from flowing downstream of the shutoff valve 534. Furthermore, once the measured concentration Dt exceeds the safe concentration Ds, the flow path switching valve 543 is switched from the first state to the second state. Therefore, even if abnormal separated water has flowed downstream of the shutoff valve 534, the abnormal separated water can be returned to the recovery tank 60 without flowing downstream of the flow path switching valve 543. Therefore, the abnormal separated water does not flow into the rinse liquid supply source 433b, the factory's water recovery line, etc., and can be returned to the recovery tank 60 for reuse.

[0124] <5-3. Other variations> In the above embodiment, the process of monitoring the concentration of IPA contained in the separated water is performed while water is being separated in the dehydrator 621 (specifically, while the vacuum pump 531 is operating), but the process may be performed continuously even while water is not being separated in the dehydrator 621. For example, the process may be performed all the time while the mixed fluid is circulating through the dehydration circulation pipe 62, regardless of whether the vacuum pump 531 is operating. Also, for example, the process may be performed all the time while the substrate processing apparatus 100 is operating.

[0125] In the above embodiment, the stop valve 542 may be omitted. For example, if the response time of the monitoring concentration sensor 533 is sufficiently short, or if the safe concentration Ds is set to a sufficiently low value, the shutoff valve 534 may be immediately closed when it is determined that the measured concentration Dt exceeds the safe concentration Ds, which may sufficiently prevent separated water containing IPA at a concentration exceeding an allowable range (e.g., an allowable range that can be sent to the rinse liquid supply source 433b, the water recovery line, etc.) from flowing downstream of the shutoff valve 534. In such cases, the stop valve 542 may be omitted.

[0126] The organic solvent recovery unit 5 according to the above embodiment may include a housing that houses some or all of the equipment disposed in the non-explosion-proof area A2. The housing preferably has a liquid-tight seal. Specifically, the housing houses, for example, the downstream piping portion 53a of the separation pipe 53, the equipment (vacuum pump 531 and condenser 532) disposed therein, the drain pipe 54, and the equipment (decomposer 541 and water stop valve 542) disposed therein. The separation pipe 53 penetrates the housing. That is, the downstream piping portion 53a of the separation pipe 53 is disposed inside the housing, the downstream piping portion 53a penetrates the housing midway, and the upstream piping portion 53b is disposed outside the housing. The portion of the housing through which the separation pipe 53 penetrates is preferably liquid-tightly sealed with a sealing member or the like. According to this modification, even if various liquids (e.g., separation liquid, cooling liquid, etc.) leak out of the housing due to an unexpected event, the liquid can be contained within the housing.

[0127] In the above embodiment, a plurality of recovery tanks 60 may be provided. When a plurality of recovery tanks 60 are provided, even while a process of separating water from the fluid mixture stored in one recovery tank 60 is being performed, the liquid collected in the cup 42 can be transferred to the other recovery tank 60. In other words, by switching the recovery tank 60 to which the liquid is transferred, 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) can be transferred without interruption. This makes it possible to shorten the cycle time from when the organic solvent supplied to the substrate W is recovered until it is supplied to the substrate W again. As a result, the amount of organic solvent used and discharged can be effectively reduced.

[0128] In the above embodiment, a plurality of purification tanks 70 may be provided. When a plurality of purification tanks 70 are provided, even while a process of purifying the concentrated fluid is being performed in one purification tank 70, the concentrated fluid obtained in the recovery tank 60 can be sent to the other purification tank 70. This makes it possible to shorten the cycle time from when the organic solvent supplied to the substrate W is recovered until it is supplied again to the substrate W. As a result, the amount of organic solvent used and discharged can be effectively reduced.

[0129] In the organic solvent recovery section 5 according to the above embodiment, the recovery tank 60 and the purification tank 70 may be a single tank. Specifically, for example, a single tank (recovery and purification tank) may be connected to the dehydration circulation pipe 62 and the purification circulation pipe 72. In this case, the mixed fluid stored in the recovery and purification tank may first be circulated through the dehydration circulation pipe 62 to form a concentrated fluid, and then the obtained concentrated fluid may be circulated through the purification circulation pipe 72 to form a purified fluid.

[0130] In the organic solvent recovery section 5 according to the above embodiment, a filter may be provided in the dehydration circulation pipe 62. That is, the substances to be removed may be removed while separating water from the mixed fluid circulating through the dehydration circulation pipe 62. In this case, the purification tank 70 may be omitted, and the recovery tank 60 may be connected directly to the supply tank 80 (without the purification tank 70 interposed therebetween).

[0131] 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.).

[0132] 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.

[0133] 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.

[0134] 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).

[0135] 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.

[0136] 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]

[0137] 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 Piping (circulation piping for dehydration) 621 Dehydrator 51 Separation membrane 622 Dehydration side liquid transfer pump 623 Heater 53 Separate piping 531 Vacuum Pump 532 Condenser 533 Monitoring concentration sensor 534 Shut-off Valve 54 Drainage piping 541 Decomposer 542 Water stop valve 543 Flow path switching valve 55 Return piping 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 A1 Explosion-proof area A2 Non-explosion-proof area De lower explosive limit concentration Ds safe concentration Dt measurement concentration

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 dehydrator provided in a pipe connected to the recovery tank and including a separation membrane that allows the water to pass through but does not allow the organic solvent to pass through; a separation pipe connected to the dehydrator and into which separated water that has passed through the separation membrane flows; a monitoring concentration sensor for measuring the concentration of the organic solvent contained in the separated water; a shutoff valve provided in the separation pipe, which, in a closed state, shuts off the flow of the separated water through the separation pipe; a control unit that closes the shutoff valve when the concentration of the organic solvent measured by the monitoring concentration sensor exceeds a safe concentration that is lower than the lower explosion limit concentration of the organic solvent; A substrate processing apparatus comprising:

2. The substrate processing apparatus according to claim 1 , a condenser provided in the separation pipe at a position downstream of the shutoff valve and configured to condense the separated water; a drainage pipe for guiding the separated water condensed in the condenser; A substrate processing apparatus comprising:

3. 3. The substrate processing apparatus according to claim 2, a stop valve provided in the drainage pipe and configured to block the flow of the separated water through the drainage pipe in a closed state; Equipped with the control unit closes the water stop valve when the concentration of the organic solvent measured by the monitoring concentration sensor exceeds the safe concentration. Substrate processing equipment.

4. 3. The substrate processing apparatus according to claim 2, a return pipe connecting a branch position defined midway in the drainage pipe to the recovery tank; a flow path switching valve provided at the branching position and switchable between a first state in which the separated water flowing from the upstream side of the drainage pipe is allowed to flow into the downstream side of the drainage pipe without flowing into the return pipe, and a second state in which the separated water flowing from the upstream side of the drainage pipe is allowed to flow into the return pipe; Equipped with the control unit switches the flow path switching valve from the first state to the second state when the concentration of the organic solvent measured by the monitoring concentration sensor exceeds the safe concentration. Substrate processing equipment.

5. 5. The substrate processing apparatus according to claim 2, a decomposer that decomposes the organic solvent contained in the separated water flowing through the drainage pipe; A substrate processing apparatus comprising:

6. 5. The substrate processing apparatus according to claim 2, the separated water is guided to the rinse liquid supply unit through the drainage pipe and supplied to the substrate as the rinse liquid; Substrate processing equipment.

7. 5. The substrate processing apparatus according to claim 1, a housing that houses the recovery tank, the piping, and the dehydrator; Equipped with The separation pipe is provided to penetrate the housing. Substrate processing equipment.

8. 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 circulation step of flowing the mixed fluid stored in the recovery tank through a pipe provided with a dehydrator having a separation membrane that allows the water to pass through but blocks the organic solvent; a separation step of causing separated water separated from the mixed fluid flowing into the dehydrator to flow into a separation pipe; a monitoring step of determining whether or not the concentration of the organic solvent contained in the separated water flowing through the separation pipe has exceeded a safe concentration that is lower than the lower explosion limit concentration of the organic solvent; a shutoff step of shutting off the flow of the separated water through the separation pipe by closing a shutoff valve provided in the separation pipe when it is determined that the concentration of the organic solvent has exceeded the safe concentration; A substrate processing method comprising:

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