Organic solvent recovery device, substrate processing system, and organic solvent recovery method

Abstract

The invention relates to an organic solvent recovery apparatus, a substrate processing system, and an organic solvent recovery method. Water can be separated from a mixed liquid with high reliability and high efficiency. The device is provided with a first pipe, a second pipe, a converging section (50), and a first dehydrator (60). The first pipe allows a mixed liquid containing an organic solvent and water to flow from a first processing unit (4) that processes a substrate (W). The second pipe allows the organic solvent or the mixed liquid to flow therethrough. The merging unit merges a mixed solution in which the solvent concentration passing through the first pipe is less than a predetermined concentration reference value with a liquid in which the solvent concentration passing through the second pipe is equal to or greater than the concentration reference value, and generates a merged mixed solution which is a mixed solution in which the solvent concentration is equal to or greater than the concentration reference value. The first dehydrator includes a first membrane separator (62) that includes a first separation membrane (62c) in which the lower limit value of the application range of the solvent concentration is a concentration reference value, and that separates water from the merged mixed liquid from the merging unit so as to increase the solvent concentration of the merged mixed liquid.

Description

Technical Field

[0001] The invention relates to an organic solvent recovery device, a substrate processing system and an organic solvent recovery method. Background Art

[0002] Patent document 1 discloses an IPA recovery system for recovering aqueous IPA (isopropyl alcohol) discharged from a processing unit that processes a substrate. The IPA recovery system includes a storage tank, a circulation piping, a pump, a dehydration unit, and a filter. Aqueous IPA from the processing unit is supplied to the storage tank. The circulation piping is connected to the storage tank so that the aqueous IPA from the storage tank is returned to the storage tank. The pump is provided in the circulation piping to transport the aqueous IPA from the upstream end to the downstream end of the circulation piping. The filter is provided in the circulation piping to remove foreign matter in the aqueous IPA. The dehydration unit is provided in the circulation piping to remove water from the aqueous IPA.

[0003] The recovery system circulates aqueous IPA through a circulation path consisting of a storage tank and circulation piping. This circulation allows the aqueous IPA to pass through the filter and dehydration unit. This increases the IPA concentration of the circulating aqueous IPA and reduces foreign matter in the aqueous IPA. In other words, this circulation results in a higher IPA concentration and clean aqueous IPA stored in the storage tank. The aqueous IPA in this storage tank is then resupplied to the processing unit. This reduces the amount of IPA waste.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-41505 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] As a dehydration unit for separating water from a mixed liquid, a membrane separator comprising a separation membrane is considered. A separation membrane is a membrane that allows water to pass through while largely blocking organic solvents. Such a membrane separator can separate water from a mixed liquid with higher energy efficiency than separation methods such as distillation. On the other hand, if the concentration of the organic solvent in the mixed liquid is low, allowing the mixed liquid to flow through the membrane separator may cause the membrane separator to malfunction.

[0009] Therefore, an object of the present invention is to provide a technology capable of separating water from a mixed liquid with high reliability and high efficiency.

[0010] Means for solving problems

[0011] The first method is an organic solvent recovery device, which comprises: a first piping, which supplies a mixed liquid containing an organic solvent and water from a first processing unit for processing a substrate; a second piping, which supplies an organic solvent or the aforementioned mixed liquid; a confluence portion, which allows the aforementioned mixed liquid having a solvent concentration less than a prescribed concentration reference value passing through the aforementioned first piping to merge with a liquid having a solvent concentration greater than the aforementioned concentration reference value passing through the aforementioned second piping to generate the aforementioned mixed liquid having a solvent concentration greater than the aforementioned concentration reference value, namely, a merged mixed liquid; and a first dehydrator including a first membrane separator, the aforementioned first membrane separator including a first separation membrane having a lower limit value of a concentration of an applicable range of solvent concentration being the aforementioned concentration reference value, and separating water from the aforementioned merged mixed liquid from the aforementioned confluence portion to increase the solvent concentration of the aforementioned merged mixed liquid.

[0012] The second method is an organic solvent recovery device involved in the first method, which is equipped with a third pipe, the third pipe is for the flow of the mixed liquid discharged from the second processing unit for processing the substrate, the liquid is a new liquid of the organic solvent that has not yet been used for the processing of the substrate, and the confluence part includes a regulator for adjusting the confluence ratio of the mixed liquid passing through the first pipe, the mixed liquid passing through the third pipe, and the new liquid passing through the second pipe.

[0013] The third embodiment is an organic solvent recovery device involved in the second embodiment, wherein the aforementioned merging section comprises: a first merging tank and a second merging tank; a recovery destination switching section, which switches the recovery destination of the aforementioned mixed liquid passing through the aforementioned first pipe and the aforementioned third pipe between the aforementioned first merging tank and the aforementioned second merging tank; a new liquid switching section, which switches the supply destination of the aforementioned new liquid between the aforementioned first merging tank and the aforementioned second merging tank; and a supply source switching section, which switches the supply source of the aforementioned mixed liquid to the aforementioned first dehydrator between the aforementioned first merging tank and the aforementioned second merging tank.

[0014] The fourth mode is an organic solvent recovery device involved in the first mode, which comprises: a low-concentration tank and a high-concentration tank; a first recovery destination switching unit, which switches between a first low-concentration state that connects the aforementioned first treatment unit with the aforementioned low-concentration tank, and a first high-concentration state that connects the aforementioned first treatment unit with the aforementioned high-concentration tank; and a control unit, which causes the aforementioned first recovery destination switching unit to select the aforementioned first low-concentration state when the solvent concentration of the aforementioned mixed liquid from the aforementioned first treatment unit is a value less than the aforementioned concentration reference value, and causes the aforementioned first recovery destination switching unit to select the aforementioned first high-concentration state when the solvent concentration of the aforementioned mixed liquid from the aforementioned first treatment unit is a value greater than the aforementioned concentration reference value, the aforementioned first piping connects the aforementioned low-concentration tank with the aforementioned confluence section, the aforementioned second piping connects the aforementioned high-concentration tank with the aforementioned confluence section, and the aforementioned confluence section includes a regulator for adjusting the confluence ratio of the aforementioned mixed liquid passing through the aforementioned first piping and the aforementioned mixed liquid passing through the aforementioned second piping.

[0015] The fifth method is an organic solvent recovery device involved in the fourth method, which is equipped with a new liquid piping, the new liquid of the organic solvent that has not yet been used for the treatment of the substrate flows, the confluence portion mixes the mixed liquid from the low-concentration tank via the first piping, the mixed liquid from the high-concentration tank via the second piping, and the new liquid via the new liquid piping, and the regulator adjusts the confluence ratio of the mixed liquid via the first piping, the mixed liquid via the second piping, and the new liquid via the new liquid piping.

[0016] The sixth mode is an organic solvent recovery device involved in the fourth or fifth mode, which further includes a second recovery destination switching unit, which switches between a second low concentration state in which the second processing unit for processing the substrate is connected to the low concentration tank, and a second high concentration state in which the second processing unit is connected to the high concentration tank. The control unit causes the second recovery destination switching unit to select the second low concentration state when the solvent concentration of the mixed liquid from the second processing unit is a value less than the concentration reference value, and causes the second recovery destination switching unit to select the second high concentration state when the solvent concentration of the mixed liquid from the second processing unit is a value greater than the concentration reference value.

[0017] The seventh method is an organic solvent recovery device involved in any one of the fourth to sixth methods, which comprises a storage unit, wherein the storage unit stores process information representing the processing content of the substrate by the first processing unit, and the control unit calculates the solvent concentration of the mixed liquid discharged from the first processing unit based on the process information.

[0018] The eighth embodiment is an organic solvent recovery device according to the seventh embodiment, wherein the first processing unit comprises: a substrate holding portion for holding the substrate and rotating the substrate; a spraying portion for sequentially spraying pure water and an organic solvent onto the main surface of the substrate held on the substrate holding portion; and a cup body having a cylindrical shape surrounding the substrate holding portion for blocking liquid scattered from the periphery of the substrate, the upstream end of the first pipe being connected to the cup body, and the process information setting the pure water flow rate and spraying time of the pure water sprayed onto the substrate, the time of spraying the pure water onto the substrate, and the time of spraying the pure water onto the substrate. The solvent flow rate and spraying time of the organic solvent, as well as the rotation speed of the aforementioned substrate, the aforementioned storage unit stores correspondence information representing the correspondence between the aforementioned rotation speed and the amount of pure water on the aforementioned main surface of the aforementioned substrate, i.e., the amount of pure water film. The aforementioned control unit calculates the aforementioned pure water film amount based on the aforementioned rotation speed of the aforementioned substrate determined based on the aforementioned process information and the aforementioned correspondence information, and calculates the solvent concentration of the aforementioned mixed liquid discharged from the aforementioned first processing unit based on the aforementioned pure water film amount, the time integral value of the aforementioned pure water flow rate, and the time integral value of the aforementioned solvent flow rate.

[0019] A ninth aspect is the organic solvent recovery device according to the fourth aspect, comprising a concentration sensor for measuring the solvent concentration of the mixed liquid, wherein the control unit controls the first recovery destination switching unit based on the solvent concentration of the mixed liquid measured by the concentration sensor.

[0020] The 10th embodiment is an organic solvent recovery device according to any one of the 1st to 9th embodiments, wherein the merging section includes: a tank into which the mixed liquids flow respectively through the 1st pipe and the 2nd pipe; and a stirring section for stirring the mixed liquid stored in the tank.

[0021] An eleventh aspect is the organic solvent recovery device according to the tenth aspect, wherein the stirring section includes a bubbler tube that ejects bubbles into the mixed liquid stored in the tank.

[0022] The twelfth aspect is the organic solvent recovery device according to the tenth aspect, wherein the stirring section includes a stirring circulation pipe connected to the tank, and the mixed liquid is circulated through the tank and the stirring circulation pipe.

[0023] The 13th method is an organic solvent recovery device involved in any one of the 1st to 12th methods, which further includes a second dehydrator, the second dehydrator separates water from the mixed liquid flowing through one of the first pipe and the second pipe, so that the solvent concentration of the mixed liquid increases, and the confluence section makes the mixed liquid passing through the other of the first pipe and the second pipe merge with the mixed liquid from the second dehydrator.

[0024] The fourteenth aspect is the organic solvent recovery device according to the thirteenth aspect, wherein the second dehydrator includes at least one of a distillation tower and an ultrasonic atomizing separator.

[0025] The 15th method is an organic solvent recovery device involved in the 13th method, wherein the aforementioned second dehydrator includes a second membrane separator, the aforementioned second membrane separator includes a second separation membrane, and separates water from the aforementioned mixed liquid to increase the solvent concentration of the aforementioned mixed liquid, and the aforementioned concentration lower limit value of the aforementioned second separation membrane is different from the aforementioned concentration lower limit value of the aforementioned first separation membrane.

[0026] The 16th method is an organic solvent recovery device involved in the 15th method, which further includes a third dehydrator arranged at a front section of the aforementioned second dehydrator, and the aforementioned third dehydrator separates water from the aforementioned mixed liquid flowing through one of the aforementioned first pipe and the aforementioned second pipe, so that the solvent concentration of the aforementioned mixed liquid increases to above the aforementioned concentration lower limit value of the aforementioned second separation membrane, and supplies the mixed liquid to the aforementioned second dehydrator.

[0027] The 17th embodiment is an organic solvent recovery device according to the 15th embodiment, wherein the second dehydrator comprises: a concentration tank storing the mixed liquid from the first pipe or the second pipe; a second circulation pipe connected to the concentration tank and provided with the second membrane separator, and a third circulation pipe connected to the concentration tank and provided with the third membrane separator; a circulation switching unit switching between a second circulation state in which the mixed liquid passes through the concentration tank and the second circulation pipe and circulates, and a third circulation state in which the mixed liquid passes through the concentration tank and the third circulation pipe and circulates; and a control unit, wherein the third membrane separator is connected to the concentration tank and the second circulation pipe. The separator includes a third separation membrane, the concentration lower limit value of the third separation membrane is lower than the concentration lower limit value of the second separation membrane, and the separation constant of the second separation membrane is higher than the separation constant of the third separation membrane. The control unit causes the circulation switching unit to select the third circulation state when the solvent concentration of the mixed liquid in the concentrating tank is less than the concentration lower limit value of the second separation membrane and greater than the concentration lower limit value of the third separation membrane, and causes the circulation switching unit to select the second circulation state when the solvent concentration of the mixed liquid in the concentrating tank is greater than the concentration lower limit value of the second separation membrane.

[0028] The 18th method is a substrate processing system, which comprises: an organic solvent recovery device involved in any one of the second, third and sixth methods; a first substrate processing device, which includes a first loading port, a plurality of the aforementioned first processing units, and a first conveying section for conveying substrates between the aforementioned first loading port and the aforementioned plurality of the aforementioned first processing units; and a second substrate processing device, which includes a second loading port, a plurality of the aforementioned second processing units, and a second conveying section for conveying substrates between the aforementioned second loading port and the aforementioned plurality of the aforementioned second processing units.

[0029] The 19th method is an organic solvent recovery method, which comprises: a merging process, in which a mixed liquid containing an organic solvent and water discharged from a first processing unit for processing a substrate is merged with an organic solvent or the aforementioned mixed liquid to generate the aforementioned mixed liquid having a concentration greater than a reference value; and a dehydration process, in which a first membrane separator including a first separation membrane having a lower limit value of an applicable range of solvent concentration being the aforementioned reference value is used to separate water from the aforementioned mixed liquid generated by the aforementioned merging process, thereby increasing the solvent concentration of the aforementioned mixed liquid.

[0030] Effects of the Invention

[0031] According to the first, eighteenth, and nineteenth methods, the confluence portion causes a mixed liquid having a solvent concentration less than the concentration reference value flowing through the first pipe to merge with a mixed liquid having a solvent concentration greater than the concentration reference value flowing through the second pipe, thereby generating a combined mixed liquid having a solvent concentration greater than the concentration reference value. Because the solvent concentration of the combined mixed liquid is greater than the lower concentration limit of the first separation membrane, the first dehydrator can reliably increase the solvent concentration of the combined mixed liquid. In addition, because the energy efficiency of membrane separation is higher than that of other methods, the first dehydrator can further efficiently increase the solvent concentration of the combined mixed liquid. That is, the organic solvent recovery device can separate water from the mixed liquid with high reliability and efficiency.

[0032] According to the second aspect, even if the mixed liquid having a concentration not less than the reference value flowing through the third pipe is insufficient, the merging portion can generate a merged mixed liquid having a concentration not less than the reference value using new liquid.

[0033] According to the third aspect, the recovery destination switching unit can alternately switch the recovery destination between the first merging tank and the second merging tank. Therefore, the mixed liquid from the first processing unit and the second processing unit can be constantly recovered.

[0034] While the first merging tank is recovering the mixed liquid from the first and second processing units, the new liquid switching unit can select the second merging tank as the destination for the new liquid. Therefore, during this period, new liquid can be supplied to the second merging tank, reliably ensuring that the solvent concentration of the mixed liquid in the second merging tank is above the concentration reference value. Furthermore, since the mixed liquid from the first and second processing units flows into the first merging tank and not into the second merging tank, concentration adjustment in the second merging tank is facilitated. Furthermore, by selecting the second merging tank as the supply source, the supply source switching unit can supply the combined mixed liquid in the second merging tank to the first dehydrator.

[0035] Similarly, when the mixed liquid is recovered in the second merging tank, the solvent concentration of the mixed liquid in the first merging tank can be adjusted, and the merged mixed liquid in the first merging tank can be supplied to the first dehydrator.

[0036] According to the fourth aspect, the mixed liquid from the first processing unit is distributed to a low-concentration tank and a high-concentration tank based on solvent concentration. Thus, the low-concentration tank stores a low-concentration mixed liquid with a solvent concentration less than a reference concentration value, while the high-concentration tank stores a high-concentration mixed liquid with a solvent concentration greater than or equal to the reference concentration value. Because the regulator adjusts the confluence ratio between the low-concentration mixed liquid from the low-concentration tank and the high-concentration mixed liquid from the high-concentration tank, the confluence unit can more reliably generate a confluent mixed liquid with a concentration greater than or equal to the reference concentration value.

[0037] According to the fifth aspect, the merging portion can merge new liquid when the high-concentration mixed liquid in the high-concentration tank is insufficient. Therefore, the merging portion can more reliably generate a mixed liquid having a concentration greater than the reference value.

[0038] According to the sixth aspect, the mixed liquid from the second treatment tank can also be distributed to the low-concentration tank and the high-concentration tank. Therefore, the possibility of insufficient mixed liquid in the high-concentration tank can be reduced.

[0039] According to the seventh aspect, since there is no need to provide a concentration sensor, the manufacturing cost can be reduced.

[0040] According to the eighth aspect, the solvent concentration can be calculated with high accuracy.

[0041] According to the ninth aspect, the solvent concentration can be obtained with high accuracy.

[0042] According to the tenth aspect, the concentration distribution of the mixed liquid can be made more uniform. Therefore, the mixed liquid having a concentration not lower than the lower limit of the first separation membrane can be more reliably flowed into the first membrane separator.

[0043] According to the eleventh aspect, since it is not necessary to provide a driving unit such as a screw in the tank, it is possible to suppress an increase in the impurity concentration in the mixed liquid.

[0044] According to the twelfth aspect, since it is not necessary to provide a driving unit such as a screw in the tank, it is possible to suppress an increase in the impurity concentration in the mixed liquid.

[0045] According to the thirteenth aspect, a mixed liquid having a concentration equal to or higher than the reference concentration value can be generated more reliably.

[0046] According to the fourteenth aspect, since the lower limit value of the concentration of the second dehydrator is low, it is easy to apply to the mixed liquid passing through the first pipe.

[0047] According to the fifteenth embodiment, the energy efficiency of membrane separation is high, so the solvent concentration of the mixed liquid can be increased more efficiently. In addition, since the concentration lower limit of the second separation membrane is different from the concentration lower limit of the first separation membrane, a second separation membrane suitable for the solvent concentration of the mixed liquid can be used.

[0048] According to the sixteenth aspect, the second dehydrator can further reliably increase the solvent concentration of the mixed liquid.

[0049] According to the seventeenth aspect, the solvent concentration of the mixed liquid can be increased with higher reliability and higher efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] [ Figure 1 ] is a diagram schematically showing an example of a substrate processing system involved in the first embodiment.

[0051] [ Figure 2 ] is a top view schematically showing an example of a substrate processing apparatus.

[0052] [ Figure 3 ] is a side view schematically showing an example of a processing unit.

[0053] [ Figure 4 ] is a diagram schematically showing another example of a confluence portion.

[0054] [ Figure 5 ] is a diagram schematically showing an example of the first dehydrator.

[0055] [ Figure 6 ] is a flowchart showing an example of the operation of the organic solvent recovery unit.

[0056] [ Figure 7 ] is a diagram schematically showing an example of a confluence portion involved in the second embodiment.

[0057] [ Figure 8 ] is a diagram for explaining an example of the operation of the organic solvent recovery unit involved in the second embodiment.

[0058] [ Figure 9] is a diagram schematically showing an example of an organic solvent recovery unit involved in the third embodiment.

[0059] [ Figure 10 ] is a flowchart showing an example of the operation of the organic solvent recovery unit involved in the third embodiment.

[0060] [ Figure 11 ] is a flowchart showing an example of the operation of the organic solvent recovery unit involved in the third embodiment.

[0061] [ Figure 12 ] is a diagram schematically showing an example of a substrate processing system involved in the fourth embodiment.

[0062] [ Figure 13 ] is a diagram schematically showing an example of a processing unit involved in the fourth embodiment.

[0063] [ Figure 14 ] is a diagram schematically showing an example of the processing unit in each process of Table 1.

[0064] [ Figure 15 ] is a graph showing an example of the distance between each position on the substrate and the center of the substrate and the thickness of the pure water liquid film at each position.

[0065] [ Figure 16 ] is a diagram schematically showing an example of the processing unit in each process of Table 2.

[0066] [ Figure 17 ] is a graph showing an example of the distance between each position on the substrate and the center of the substrate and the thickness of the liquid film at each position.

[0067] [ Figure 18 ] is a flowchart showing an example of the operation of the concentration estimating unit.

[0068] [ Figure 19 ] is a diagram schematically showing a second example of a substrate processing system according to the fourth embodiment.

[0069] [ Figure 20 ] is a diagram schematically showing a first example of the first dehydrator involved in the fifth embodiment.

[0070] [ Figure 21 ] is a flowchart showing an example of the operation of the organic solvent recovery unit involved in the fifth embodiment.

[0071] [ Figure 22 ] is a diagram schematically showing a second example of the first dehydrator involved in the fifth embodiment.

[0072] [ Figure 23] is a diagram showing an example of a substrate processing system involved in the sixth embodiment.

[0073] [ Figure 24 ] is a diagram schematically showing a first example of the second dehydrator.

[0074] [ Figure 25 ] is a diagram schematically showing a second example of the second dehydrator.

[0075] [ Figure 26 ] is a diagram schematically showing a third example of the second dehydrator.

[0076] [ Figure 27 ] is a diagram schematically showing an example of a substrate processing system involved in the seventh embodiment.

[0077] [ Figure 28 ] is a diagram schematically showing an example of a substrate processing system involved in the eighth embodiment.

[0078] [ Figure 29 ] is a diagram schematically showing an example of an organic solvent recovery unit involved in the ninth embodiment.

[0079] Description of Reference Numerals

[0080] 1 Load port 1, load port 2 (load port)

[0081] 100 Substrate processing equipment

[0082] 100A 1st substrate processing device

[0083] 100B Second substrate processing device

[0084] 2. 1st transport unit, 2nd transport unit (indexer robot)

[0085] 3 1st conveying section, 2nd conveying section (main conveying robot)

[0086] 4 1st processing unit, 2nd processing unit (processing unit)

[0087] 41 Substrate holding portion (rotating chuck)

[0088] 42 cup body

[0089] 430 ejection part

[0090] 50 Confluence Department

[0091] 500 Recycling Destination Switching Department

[0092] 500A 1st collection destination switching unit

[0093] 500B Second collection destination switching unit

[0094] 51A 1st pipe (recovery pipe)

[0095] 51B 2nd pipe, 3rd pipe (recovery pipe)

[0096] 51L 1st piping (low concentration piping)

[0097] 51H Second pipe (high concentration pipe)

[0098] 550 Supply source switching unit

[0099] 56 Second piping, new fluid piping

[0100] 580 New Liquid Switching Unit

[0101] 6 Control Unit

[0102] 60 No. 1 dehydrator

[0103] 62 No. 1 membrane separator

[0104] 62c 1st separation membrane

[0105] 70 Second Dehydrator

[0106] 700 No. 3 Dehydrator

[0107] 701 Distillation Tower

[0108] 704 Ultrasonic Atomization Separator

[0109] 72 Second membrane separator

[0110] 720 No. 3 membrane separator

[0111] 72c Second separation membrane

[0112] 720c 3rd separation membrane

[0113] 73 Second circulation piping

[0114] 790 Circular Switching Department

[0115] 90 Regulator

[0116] 95 Mixing section

[0117] 951 Bubble Tube

[0118] 96 Mixing circulation piping

[0119] D1 process information

[0120] D2 correspondence information

[0121] Sn5 concentration sensor

[0122] Tk1 tank (concentrate tank)

[0123] Tk2 tank (combining tank)

[0124] Tk21 tank, first confluence tank

[0125] Tk22 tank, second confluence tank

[0126] Tk2L low concentration tank

[0127] Tk2H High Concentration Tank

[0128] Tk3 supply tank

[0129] S1 merging process (step)

[0130] S2 Dehydration process (step)

[0131] W substrate DETAILED DESCRIPTION

[0132] The following describes the embodiments in detail with reference to the accompanying drawings. It should be noted that in the drawings, the dimensions and quantities of various components are exaggerated or simplified as necessary for ease of understanding. Furthermore, components having the same structure and function are denoted by the same reference numerals, and duplicate descriptions are omitted in the following description.

[0133] In the following description, identical components are denoted by identical reference numerals and have identical names and functions, and detailed descriptions thereof may be omitted to avoid redundancy.

[0134] In the following description, even when ordinal numbers such as "first" or "second" are used, these terms are used for convenience in order to facilitate understanding of the contents of the embodiments and are not limited to the order generated by these ordinal numbers.

[0135] When using expressions that express relative or absolute positional relationships (for example, "in one direction," "along a direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.), unless otherwise specified, the expression not only strictly expresses the positional relationship, but also expresses a state of relative displacement in angle or distance within a tolerance or a range that can achieve the same degree of function. When using expressions that express an equal state (for example, "same," "equal," "homogeneous," etc.), unless otherwise specified, the expression not only expresses a state of quantitative strict equality, but also expresses a state of tolerance or a difference that can achieve the same degree of function. When using expressions that express a shape (for example, "quadrilateral" or "cylindrical," etc.), unless otherwise specified, the expression not only expresses the shape strictly geometrically, but also expresses a shape with, for example, concave-convex corners, chamfers, etc., within a range that can achieve the same degree of effect. When using expressions such as "having," "including," or "having" a constituent element, the expression is not an exclusive expression that excludes the presence of other constituent elements. When the expression "at least any one of A, B, and C" is used, the expression includes: only A; only B; only C; any two of A, B, and C; and all of A, B, and C.

[0136] <First embodiment>

[0137] <1. Substrate Processing Apparatus>

[0138] Figure 1 It is a diagram schematically showing an example of a substrate processing system 1000 according to the first embodiment. Figure 1 In the example of FIG. 1 , the substrate processing system 1000 includes a plurality of substrate processing apparatuses 100 , an organic solvent recovery apparatus (organic solvent recovery unit 5 ), and a control unit 6 . Figure 1 , a substrate processing apparatus 100A (corresponding to a first substrate processing apparatus) and a substrate processing apparatus 100B (corresponding to a second substrate processing apparatus) are shown as a plurality of substrate processing apparatuses 100. The substrate processing apparatus 100A and the substrate processing apparatus 100B may have the same configuration. Figure 2 It is a plan view schematically showing an example of the substrate processing apparatus 100 .

[0139] The substrate processing apparatus 100 is a so-called single-wafer processing apparatus that processes target substrates W one by one. The target substrates W in the substrate processing apparatus 100 are, for example, semiconductor substrates. The target substrates W are, for example, disk-shaped.

[0140] The substrate processing apparatus 100A includes a load port 1 (equivalent to a first load port), an indexer robot 2 (equivalent to a first transport unit), a main transport robot 3 (equivalent to the first transport unit), and a processing unit 4 (equivalent to a first processing unit). Similarly, the substrate processing apparatus 100B includes a load port 1 (equivalent to a second load port), an indexer robot 2 (equivalent to a second transport unit), a main transport robot 3 (equivalent to a second transport unit), and a processing unit 4 (equivalent to a second processing unit).

[0141] The loading port 1 is an interface for carrying out the entry and exit of a substrate W relative to a carrier C, which is a storage container for accommodating multiple substrates. For example, a plurality of loading ports 1 are provided (three in the figure). For example, a plurality of loading ports 1 are arranged in a row in the horizontal direction. The carrier C can be a type that accommodates the substrate W in a confined space (for example, a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface) port, etc.), or a type that exposes the substrate W to external gas (for example, an OC (Open Cassette, open cassette) etc.).

[0142] The indexer robot 2 is a transport device for transporting substrates W. As an example, the indexer robot 2 is a horizontal multi-joint robot, which includes a pair of hands 21, 21 for holding the substrate W and an arm 22 connected to each hand 21. In addition, the indexer robot 2 includes a driving mechanism (not shown) for rotating each hand 21 and flexing, extending, rotating, and lifting each arm 22. The indexer robot 2 transports the substrate W between the main transport robot 3 and the carrier C loaded on the loading port 1. That is, the indexer robot 2 accesses the carrier C loaded on the loading port 1 to perform a carry-out action (i.e., an action of taking out the substrate W contained in the carrier C with the hand 21) and a carry-in action (i.e., an action of containing the substrate W held by the hand 21 in the carrier C). In addition, the indexer robot 2 accesses the receiving position and performs the receiving and receiving of the substrate W between the main transport robot 3 and the main transport robot 3.

[0143] The main transport robot 3 is a transport device that transports the substrate W. As an example, the main transport robot 3 includes a horizontal multi-joint robot, a pair of hands 31, 31 for holding the substrate W, and an arm 32 connected to each hand 31. In addition, the main transport robot 3 includes a driving mechanism (not shown) for rotating each hand 31 and flexing, extending, rotating, and lifting each arm 32. The main transport robot 3 transports the substrate W between the indexer robot 2 and each processing unit 4. That is, the main transport robot 3 accesses the receiving position and receives and receives the substrate W between the indexer robot 2. In addition, the main transport robot 3 accesses the processing unit 4 to perform a carry-in action (that is, an action of carrying the substrate W held by the hand 31 into the processing unit 4) and a carry-out action (that is, an action of carrying the substrate W in the processing unit 4 with the hand 31).

[0144] The processing unit 4 performs a predetermined process on the substrate W using a processing liquid (e.g., a chemical solution, a rinse solution, and IPA). Here, for example, a plurality (e.g., three) of processing units 4 stacked vertically form a tower, and multiple (four in the example shown) of these towers are arranged to surround the main transfer robot 3. The specific structure of the processing unit 4 is described below.

[0145] The organic solvent recovery unit 5 recovers organic solvent from the treatment unit 4, purifies the recovered organic solvent, and supplies it back to the treatment unit 4. For example, an organic solvent recovery unit 5 may be provided in each of the multiple towers in a one-to-one correspondence, with each organic solvent recovery unit 5 recovering and supplying organic solvent to each treatment unit 4 contained in the corresponding tower. The specific structure of the organic solvent recovery unit 5 is described below.

[0146] 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) of the substrate processing system 1000. The control unit 6 is composed of, for example, a general computer having a circuit. As an example, the control unit 6 includes a CPU (Central Processor Unit) as a central processing unit for performing various calculations (data processing), a ROM (Read Only Memory) for storing basic programs, a RAM (Random Access Memory) used as an operating area when the CPU performs prescribed processing (data processing), a storage device composed of non-volatile storage devices such as flash memory and hard disk devices, and a bus connecting them to each other. A program that specifies the processing performed by the control unit 6 can be stored in the storage device or RAM. In this case, for example, the program can be executed by the CPU, thereby controlling the various units of the substrate processing device 100 through the control unit 6, and performing the processing specified by the program in the substrate processing device 100. That is, a circuit that executes a program by the CPU to perform processing specified by the program can be implemented in the control unit 6. Of course, part or all of the control performed by the control unit 6 (part or all of the circuits implemented in the control unit 6) can also be executed (implemented) by hardware such as a dedicated logic circuit.

[0147] <2. Processing Unit>

[0148] Reference Figure 3 The processing unit 4 will be described. Figure 3 It is a side view schematically showing an example of the processing unit 4 .

[0149] <2-1. Configuration of Processing Unit>

[0150] The processing unit 4 performs a predetermined process on the substrate W using a processing liquid (e.g., a chemical solution, a rinse solution, and IPA). The processing unit 4 includes, for example, a spin chuck 41, which is an example of a substrate holding unit, a cup 42, and a discharge unit 430. The discharge unit 430 includes a nozzle 43. The spin chuck 41, cup 42, and nozzle 43 are housed in a processing chamber 44.

[0151] The rotating chuck 41 holds the substrate W in a horizontal posture (a posture in which the thickness direction of the substrate W is along the up-down direction (vertical direction)) and rotates the substrate W around an axis (rotation axis) A extending up and down through the center of its main surface. Specifically, the rotating chuck 41 includes, for example, a rotating base 411. The rotating base 411 is a disc-shaped component, and is arranged in a posture in which the thickness direction is along the up-down direction. A plurality of chuck pins 412 are provided on the upper surface of the rotating base 411. The plurality of chuck pins 412 are arranged at equal intervals along the circumference corresponding to the periphery of the substrate W. A link mechanism (not shown) is connected to the plurality of chuck pins 412 to move them between abutment positions and open positions. The "abutment position" refers to the position where the chuck pins 412 abut against the periphery of the substrate W. The "open position" refers to the position where the chuck pins 412 are away from the periphery of the substrate W. When the plurality of chuck pins 412 are respectively arranged in the abutment positions, the substrate W is held (stuck) above the rotating base 411 in a horizontal posture. In addition, when the plurality of chuck pins 412 are respectively arranged in the open position, the holding of the substrate W is released. The link mechanism switches the position of the chuck pin 412 according to the instruction from the control unit 6. That is, the time point of holding the substrate W, the time point of releasing the holding of the substrate W, etc. are controlled by the control unit 6. In addition, the rotating base 411 is connected to the rotating motor 414 via the shaft 413 coaxially arranged with the rotation axis A. The shaft 413 and the rotating motor 414 are housed in the cover 415. The rotating motor 414 rotates the shaft 413 around the rotation axis A. As a result, the rotating base 411 and the substrate W held thereon rotate around the rotation axis A. The rotating motor 414 rotates the rotating base 411 according to the instruction from the control unit 6. That is, the rotation speed of the rotating base 411 (and the substrate W), the start time point of the rotation, the end time point of the rotation, etc. are controlled by the control unit 6.

[0152] The cup body 42 has a cylindrical shape that surrounds the spin chuck 41 and receives the processing liquid discharged from the substrate W held and rotating on the spin chuck 41. Specifically, the cup body 42 includes, for example, a cylindrical guide portion 421 coaxially arranged with the rotation axis A, an inclined portion 422 connected to the upper end of the guide portion 421 and tapering upward, and a liquid receiving portion 423 connected to the lower end of the guide portion 421 and forming an upwardly open annular groove. The liquid receiving portion 423 is provided with a cup-side recovery pipe (specifically, a cup-side recovery pipe for a chemical solution (not shown) and a cup-side recovery pipe 424 for IPA) to recover the liquid received there. Furthermore, a cup-body lifting mechanism 425 is connected to the cup body 42 to raise and lower the cup body between a lower position and an upper position. The "lower position" is a position in which the upper end of the cup body 42 (specifically, the upper end of the inclined portion 422) is positioned below the substrate W held on the spin chuck 41. The "upper position" is a position where the upper end of the cup 42 is positioned above the substrate W held by the spin chuck 41. The cup lifting mechanism 425 lifts and lowers the cup 42 according to instructions from the control unit 6. That is, the position of the cup 42 is controlled by the control unit 6.

[0153] The discharge unit 430 (specifically, the nozzle 43) discharges the processing liquid toward the upper surface of the substrate W held by the spin chuck 41. Here, for example, separate nozzles 43 are provided for each type of processing liquid. Specifically, there are provided nozzles 43 for discharging a chemical liquid (hereinafter also referred to as "chemical liquid nozzle 43a"), nozzles 43 for discharging a rinse liquid (hereinafter also referred to as "rinse liquid nozzle 43b"), and nozzles 43 for discharging IPA (hereinafter also referred to as "IPA nozzle 43c").

[0154] The chemical liquid nozzle 43a sprays chemical liquid toward the upper surface of the substrate W held on the spin chuck 41. The chemical liquid nozzle 43a is connected to the chemical liquid supply source 433a via a chemical liquid pipe 432a in which a chemical liquid valve 431a is inserted. When the chemical liquid valve 431a is opened, the chemical liquid passes through the chemical liquid pipe 432a and is supplied to the chemical liquid nozzle 43a, and the chemical liquid is sprayed from the chemical liquid nozzle 43a. The chemical liquid valve 431a opens and closes according to instructions from the control unit 6. That is, the spraying time point of the chemical liquid from the chemical liquid nozzle 43a is controlled by the control unit 6. The chemical liquid is, for example, hydrofluoric acid. Of course, the chemical liquid is not limited to hydrofluoric acid, and can also be a liquid containing at least one of sulfuric acid, acetic acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, ammonia water, hydrogen peroxide water, organic acid (for example, citric acid, oxalic acid, etc.), organic base (for example, TMAH: tetramethylammonium hydroxide, etc.), surfactant, and anti-corrosion agent.

[0155] The rinse liquid nozzle 43b discharges rinse liquid toward the upper surface of the substrate W held by the spin chuck 41. The rinse liquid nozzle 43b is connected to a rinse liquid supply source 433b via a rinse liquid pipe 432b, into which a rinse liquid valve 431b is inserted. When the rinse liquid valve 431b is opened, rinse liquid passes through the rinse liquid pipe 432b and is supplied to the rinse liquid nozzle 43b, where it is discharged. The rinse liquid valve 431b opens and closes in response to instructions from the control unit 6. Specifically, the timing of the discharge of the rinse liquid from the rinse liquid nozzle 43b is controlled by the control unit 6. The rinse liquid is, for example, pure water (deionized water). Of course, the rinse liquid is not limited to pure water and may also be any of carbonated water, electrolytically ionized water, hydrogenated water, ozone water, and hydrochloric acid water with a diluted concentration (e.g., approximately 10 to 100 ppm).

[0156] The IPA nozzle 43c ejects IPA (i.e., a liquid primarily composed of IPA) toward the upper surface of the substrate W held on the spin chuck 41. The IPA nozzle 43c is connected to the organic solvent recovery unit 5 via an IPA pipe 432c, into which an IPA valve 431c is inserted. When the IPA valve 431c is opened, IPA flows through the IPA pipe 432c and is supplied to the IPA nozzle 43c, whereupon IPA is ejected from the IPA nozzle 43c. The IPA valve 431c opens and closes in response to instructions from the control unit 6. Specifically, the timing of IPA ejection from the IPA nozzle 43c is controlled by the control unit 6.

[0157] It should be noted that a nozzle moving mechanism that moves the nozzles 43a, 43b, and 43c between a processing position and a retreat position may be connected to at least one of the chemical liquid nozzle 43a, the rinse liquid nozzle 43b, and the IPA nozzle 43c. 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 "retreat position" is a position where the nozzles 43a, 43b, and 43c are located outside (radially outward) of 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 according to instructions from the control unit 6. In other words, the positions of the nozzles 43a, 43b, and 43c are controlled by the control unit 6.

[0158] <2-2. Operation of Processing Unit>

[0159] An example of the operation of the processing unit 4 will be described. The operation of the processing unit 4 is performed under the control of the control unit 6 (i.e., the control unit 6 controls the chuck pin 412, the rotary motor 414, the cup body lifting mechanism 425, the chemical liquid valve 431a, the rinse liquid valve 431b, the IPA valve 431c, etc.).

[0160] When the main transfer robot 3 carries the substrate W into the processing chamber 44 , the spin chuck 41 holds the substrate W. Next, the spin chuck 41 starts rotating.

[0161] In this state, the chemical liquid valve 431a is opened. Then, the chemical liquid is sprayed from the chemical liquid nozzle 43a toward the upper surface of the substrate W held and rotating on the spin chuck 41. Thus, the chemical liquid is supplied to the entire area of ​​the upper surface of the substrate W, and the substrate W is treated with the chemical liquid (chemical liquid treatment process). For example, when hydrofluoric acid is used as the chemical liquid, foreign matter such as particles is removed from the substrate W. During the chemical liquid treatment process, the cup body 42 is arranged in the upper position. Therefore, the chemical liquid flying around the substrate W is blocked by the cup body 42. That is, the chemical liquid flying around the substrate W is blocked by the inclined portion 422, guided downward by the guide portion 421, and collected in the liquid receiving portion 423. The chemical liquid blocked by the cup body 42 (that is, the chemical liquid collected in the liquid receiving portion 423) is recovered through the cup body side recovery pipe (not shown) for the chemical liquid.

[0162] The chemical liquid valve 431a is closed at a time point after a predetermined time has passed since the start of the chemical liquid spraying. Thus, the chemical liquid is stopped from being sprayed from the chemical liquid nozzle 43a. Next, the rinse liquid valve 431b is opened. Thus, the rinse liquid is sprayed from the rinse liquid nozzle 43b toward the upper surface of the substrate W held and rotating on the spin chuck 41. Thus, the rinse liquid is supplied to the entire area of ​​the upper surface of the substrate W, and the chemical liquid attached to the substrate W is washed away by the rinse liquid (rinsing treatment process). The cup body 42 is also arranged in the upper position during the rinsing treatment process. Therefore, the chemical liquid and the rinse liquid scattered around the substrate W are blocked by the cup body 42. The chemical liquid and the rinse liquid blocked by the cup body 42 are recovered through the cup body side recovery pipe (not shown) for the chemical liquid.

[0163] The rinse liquid valve 431b is closed at a time point after a predetermined time has passed since the start of the rinse liquid spraying. Thus, the rinse liquid is stopped from being sprayed from the rinse liquid nozzle 43b. Next, the IPA valve 431c is opened. Thus, IPA is sprayed from the IPA nozzle 43c toward the upper surface of the substrate W held and rotating on the spin chuck 41. Thus, IPA is supplied to the entire area of ​​the upper surface of the substrate W, and the rinse liquid attached to the substrate W is replaced with IPA (IPA supply process). The cup body 42 is also arranged in the upper position during the IPA supply process. Therefore, the rinse liquid and IPA that fly around the substrate W are blocked by the cup body 42. The rinse liquid and IPA blocked by the cup body 42 are recovered through the cup body side recovery pipe 424 for IPA.

[0164] The IPA valve 431c is closed at a time point after a predetermined time has passed since the start of IPA supply. Thus, the discharge of IPA from the IPA nozzle 43c stops. At this stage, the rinsing liquid on the substrate W is completely replaced by IPA, forming a liquid film of IPA covering the entire area of ​​the upper surface of the substrate W. Next, the spin chuck 41 starts to rotate at high speed. As a result, the substrate W rotates at high speed, and the IPA on the substrate W is thrown to the surroundings of the substrate W due to centrifugal force (spin drying process). The cup body 42 is also arranged in the upper position during the period when the substrate W rotates at high speed. Therefore, the IPA scattered to the surroundings of the substrate W is blocked by the cup body 42. The IPA blocked by the cup body 42 is recovered through the cup body side recovery pipe 424 for IPA.

[0165] After a predetermined time has passed since the spin chuck 41 started rotating at high speed, the spin chuck 41 stops rotating. During this stage, the IPA is removed from the substrate W, and the substrate W is dried. The dried substrate W is carried out of the processing chamber 44 by the main transfer robot 3 .

[0166] The above completes a series of processes for one substrate W. In the processing unit 4 , the above series of operations are repeated, whereby a plurality of substrates W are processed one by one in sequence.

[0167] <2-3. Discharge of Pure Water and Organic Solvent from Treatment Unit 4>

[0168] In the above example, since the processing unit 4 sequentially supplies pure water and an organic solvent (e.g., IPA) to the main surface of the substrate W, the pure water and the organic solvent flow into the cup-side recovery pipe 424. In other words, a mixture of water and the organic solvent can flow into the cup-side recovery pipe 424. The concentration of the organic solvent in this mixture (hereinafter referred to as the solvent concentration) depends on the type of processing performed on the substrate W by the processing unit 4. For example, if the flow rate of pure water supplied to the substrate W is high, the solvent concentration (average value) of the mixture flowing through the cup-side recovery pipe 424 will be low.

[0169] In addition, there are cases where almost no pure water is used for the substrate W. For example, sometimes a metal film (such as wiring) is exposed on the main surface of the substrate W. In this case, almost no pure water is used for the substrate W. In this case, the solvent concentration (average value) of the mixed liquid flowing through the cup-side recovery pipe 424 becomes high. For example, in the latter stage of the manufacturing process of a semiconductor device, since wiring is formed on the main surface of the substrate W, the metal film serving as wiring is exposed on the main surface of the substrate W. Therefore, in the substrate processing apparatus 100 used in the latter stage, the solvent concentration of the mixed liquid flowing through the cup-side recovery pipe 424 tends to be higher. On the contrary, in the substrate processing apparatus 100 used in the front stage, the solvent concentration of the mixed liquid flowing through the cup-side recovery pipe 424 tends to be lower.

[0170] Here, as an example, the substrate processing apparatus 100A is a front-end substrate processing apparatus 100. In this apparatus, the solvent concentration of the mixed liquid discharged from each processing unit 4 of the substrate processing apparatus 100A tends to be relatively low. Also, here, as an example, the substrate processing apparatus 100B is a back-end substrate processing apparatus 100. In this apparatus, the solvent concentration of the mixed liquid discharged from each processing unit 4 of the substrate processing apparatus 100B tends to be relatively high.

[0171] The mixed liquid from each substrate processing apparatus 100 passes through the recovery pipe 51 and is supplied to the organic solvent recovery unit 5 (see Figure 1 Hereinafter, the recovery pipe 51 connected to the substrate processing apparatus 100A is referred to as the recovery pipe 51A, and the recovery pipe 51 connected to the substrate processing apparatus 100B is referred to as the recovery pipe 51B. The downstream ends of the plurality of cup-side recovery pipes 424 of the corresponding substrate processing apparatus 100 are connected to the recovery pipe 51.

[0172] In the first embodiment, as an example, the solvent concentration (average value) of the mixed liquid flowing from the substrate processing apparatus 100A through the recovery pipe 51A is lower than a concentration reference value described later, for example, 30 wt % or less. Furthermore, in the first embodiment, as an example, the solvent concentration (average value) of the mixed liquid flowing from the substrate processing apparatus 100B through the recovery pipe 51B is higher than the concentration reference value, for example, 70 wt % or more.

[0173] <3. Overview of Organic Solvent Recovery Unit 5 (Organic Solvent Recovery Device)>

[0174] Reference Figure 1 The structure of the organic solvent recovery part 5 will be described. Hereinafter, the outline of the organic solvent recovery part 5 will be described first, and then each structure of the organic solvent recovery part 5 will be described in detail.

[0175] The organic solvent recovery section 5 includes a confluence section 50 and a first dehydrator 60. The confluence section 50 merges the mixed liquid passing through the recovery pipe 51A (equivalent to the first pipe) and the mixed liquid passing through the recovery pipe 51B (equivalent to the second pipe or the third pipe). That is, the confluence section 50 merges a mixed liquid having a solvent concentration lower than the concentration reference value and a mixed liquid having a solvent concentration higher than the concentration reference value. Hereinafter, the mixed liquid with a low solvent concentration flowing into the confluence section 50 will also be referred to as a low-concentration mixed liquid, and the mixed liquid with a high solvent concentration flowing into the confluence section 50 will be referred to as a high-concentration mixed liquid. Here, the confluence section 50 generates a mixed liquid higher than the concentration reference value by this confluence. Hereinafter, the mixed liquid merged by the confluence section 50 will also be referred to as a confluent mixed liquid.

[0176] Figure 1In the example of FIG, the merging portion 50 includes a merging tank Tk2. The low-concentration mixed liquid and the high-concentration mixed liquid are supplied to the merging tank Tk2. Here, the solvent concentration of the merging mixed liquid stored in the merging tank Tk2 is higher than the concentration reference value. Figure 1 In the example of , the merging portion 50 supplies the merged mixed liquid to the first dehydrator 60 through the liquid feeding pipe 53 .

[0177] The first dehydrator 60 includes a first membrane separator 62. The combined mixed liquid from the joining portion 50 flows into the first membrane separator 62. The first membrane separator 62 separates water from the combined mixed liquid to increase the solvent concentration of the combined mixed liquid.

[0178] like Figure 1 As shown, the first membrane separator 62 includes a first mixing path 62a, a first water path 62b, and a first separation membrane 62c. The combined mixed liquid flows into the first mixing path 62a. The first separation membrane 62c separates the first mixing path 62a and the first water path 62b. The first separation membrane 62c is a membrane that allows water in the combined mixed liquid to pass through and substantially blocks organic solvents. A portion of the water in the combined mixed liquid that flows into the first mixing path 62a passes through the first separation membrane 62c and flows into the first water path 62b. As a result, the solvent concentration of the combined mixed liquid that passes through the first mixing path 62a becomes higher than the solvent concentration of the combined mixed liquid immediately before it flows into the first mixing path 62a. The first dehydrator 60 uses the first membrane separator 62 to increase the solvent concentration of the combined mixed liquid to a predetermined reuse reference value or above. The reuse reference value refers to the solvent concentration that can be used in the treatment unit 4 and can be set in advance, for example. Hereinafter, the combined mixed liquid in which the solvent concentration is increased to or above the reuse reference value is also referred to as reused liquid. It can also be said that the first dehydrator 60 separates water from the combined mixed liquid from the merging portion 50 to generate reused liquid.

[0179] The upstream end of a liquid supply pipe 85 is connected to the first dehydrator 60, and the downstream end of the liquid supply pipe 85 is connected to a supply tank Tk3 for supplying the treatment unit 4. The first dehydrator 60 supplies the reused liquid to the supply tank Tk3 via the liquid supply pipe 85. The mixed liquid in the supply tank Tk3 is then supplied to the treatment unit 4 again.

[0180] Figure 1In the example shown, the liquid supply pipe 85 includes a common pipe 850, a first branch pipe 851, and a second branch pipe 852. The upstream end of the common pipe 850 is connected to the first dehydrator 60, and the downstream end of the common pipe 850 is connected to the upstream end of the first branch pipe 851 and the upstream end of the second branch pipe 852. The downstream end of the first branch pipe 851 is connected to the supply tank Tk3 of the substrate processing apparatus 100A, and the downstream end of the second branch pipe 852 is connected to the supply tank Tk3 of the substrate processing apparatus 100B. A liquid supply valve 861 is inserted into the first branch pipe 851, and a liquid supply valve 862 is inserted into the second branch pipe 852.

[0181] When the controller 6 opens the liquid supply valve 861, the reused liquid from the first dehydrator 60 can be supplied to the supply tank Tk3 of the substrate processing apparatus 100A. When the controller 6 opens the liquid supply valve 862, the reused liquid from the first dehydrator 60 can be supplied to the supply tank Tk3 of the substrate processing apparatus 100B. The reused liquid in the supply tank Tk3 is resupplied to the processing unit 4.

[0182] As described above, the organic solvent recovery unit 5 increases the solvent concentration of the mixed liquid discharged from the processing unit 4 to generate a reused liquid. This reused liquid is then supplied to the processing unit 4 again. In other words, the substrate processing apparatus 100 reuses the organic solvent in the mixed liquid discharged from the processing unit 4. This reduces the amount of organic solvent waste and enables more efficient use of the organic solvent. In other words, the organic solvent recovery unit 5 contributes to liquid conservation.

[0183] However, the first separation membrane 62c has an applicable range of solvent concentration. That is, the first separation membrane 62c can appropriately separate water from a mixed liquid having a solvent concentration within the applicable range. On the other hand, when a mixed liquid having a solvent concentration less than the lower limit of the applicable range flows into the first membrane separator 62, a malfunction may occur in the first separation membrane 62c. For example, the first membrane separator 62 may not be able to fully separate water from the mixed liquid. Alternatively, the proportion of water molecules passing through the first separation membrane 62c exceeds the allowable value, thereby partially dissolving the crystal structure constituting the first separation membrane 62c, resulting in a significantly shortened service life of the first separation membrane 62c. Hereinafter, the lower limit of the applicable range of solvent concentration is referred to as the lower limit of concentration. As an example, the lower limit of concentration of the first separation membrane 62c is 50 wt%.

[0184] Here, the concentration reference value is the lower limit of the concentration of the first separation membrane 62c. That is, in the first embodiment, since the solvent concentration of the mixed liquid discharged from the substrate processing apparatus 100A is lower than the concentration reference value, when the mixed liquid is processed by the first dehydrator 60, it may cause a malfunction in the first membrane separator 62.

[0185] Therefore, the merging portion 50, located upstream of the first dehydrator 60, merges the high-concentration mixed liquid discharged from the substrate processing apparatus 100B with the low-concentration mixed liquid from the substrate processing apparatus 100A, generating a combined mixed liquid having a solvent concentration greater than the reference concentration value. Because the solvent concentration of the combined mixed liquid is greater than the lower concentration limit of the first separation membrane 62c, the first dehydrator 60 can appropriately separate water from the combined mixed liquid using the first membrane separator 62. In other words, the first dehydrator 60 can reliably increase the solvent concentration of the combined mixed liquid to generate a reusable liquid.

[0186] The first dehydrator 60 separates water from the combined mixed liquid using the first membrane separator 62. Since membrane separation has higher energy efficiency than other separation methods such as distillation, the first dehydrator 60 can more efficiently increase the solvent concentration of the combined mixed liquid.

[0187] As described above, the organic solvent recovery unit 5 can increase the solvent concentration of the mixed liquid with higher reliability and higher efficiency. In addition, since the first membrane separator 62 has a small device size, the organic solvent recovery unit 5 can be realized with a smaller size.

[0188] <3-1. Specific example of the organic solvent recovery unit 5>

[0189] The organic solvent recovery unit 5 can be housed in the first housing box 50a (see Figure 2 As an example, the first storage box 50a is disposed outside the outer wall 100a of the substrate processing apparatus 100 (for example, below the clean room where the substrate processing apparatus 100 is installed (for example, downstairs)).

[0190] <Confluence 50>

[0191] Figure 1 In the example shown in FIG. , the merging portion 50 includes a merging pipe 518 and a merging tank Tk2. The upstream end of the merging pipe 518 is connected to the downstream end of the recovery pipe 51A and the downstream end of the recovery pipe 51B, and the downstream end of the merging pipe 518 is connected to the merging tank Tk2.

[0192] Figure 1 In the example of FIG, a recovery valve 52 is inserted into the recovery pipe 51. Specifically, a recovery valve 52A is inserted into the recovery pipe 51A, and a recovery valve 52B is inserted into the recovery pipe 51B.

[0193] When the control unit 6 opens the recovery valve 52A, the mixed liquid from the substrate processing apparatus 100A passes through the recovery pipe 51A and the merging pipe 518 and is supplied to the merging tank Tk2. In addition, when the control unit 6 opens the recovery valve 52B, the mixed liquid from the substrate processing apparatus 100B passes through the recovery pipe 51B and the merging pipe 518 and is supplied to the merging tank Tk2. Thus, the merging mixed liquid is stored in the merging tank Tk2. It should be noted that Figure 1 Alternatively, the downstream end of the recovery pipe 51A and the downstream end of the recovery pipe 51B may be directly connected to the junction tank Tk2.

[0194] Alternatively, the low-concentration mixed liquid from the substrate processing apparatus 100A can temporarily flow into a low-concentration buffer tank (not shown), while the high-concentration mixed liquid from the substrate processing apparatus 100B can temporarily flow into a high-concentration buffer tank (not shown). For example, the low-concentration buffer tank can be connected to a recovery pipe 51A upstream of the recovery valve 52A, and the high-concentration buffer tank can be connected to a recovery pipe 51B upstream of the recovery valve 52B. In this case, the low-concentration mixed liquid from the low-concentration buffer tank and the high-concentration mixed liquid from the high-concentration buffer tank flow into a merging tank Tk2.

[0195] The supply rate of the low-concentration mixed liquid supplied to the merging tank Tk2 can be adjusted by the recovery valve 52A. Similarly, the supply rate of the high-concentration mixed liquid supplied to the merging tank Tk2 can be adjusted by the recovery valve 52B.

[0196] However, it is also conceivable that the discharge rate of the high-concentration mixed liquid from the substrate processing apparatus 100B becomes smaller than the discharge rate of the low-concentration mixed liquid from the substrate processing apparatus 100A. In this case, there may be insufficient high-concentration mixed liquid to generate a combined mixed liquid having a solvent concentration greater than the reference concentration value. Therefore, a new liquid of the organic solvent may be supplied to the combining portion 50. Figure 4 This is a diagram schematically showing another example of the merging portion 50 . Figure 4 In the example shown, the downstream end of a new liquid pipe 56 is further connected to the confluence tank Tk2 of the confluence section 50. A new liquid supply source is connected to the upstream end of the new liquid pipe 56. The new liquid supply source is a source of unused organic solvent that has not yet been supplied to the substrate W. The solvent concentration of the new liquid is naturally higher than the reference concentration value, for example, 99.8 wt% or higher. A new liquid valve 57 is inserted into the new liquid pipe 56.

[0197] When the controller 6 opens the new liquid valve 57, new liquid from the new liquid supply source passes through the new liquid pipe 56 and is supplied to the merging tank Tk2. Thus, the merging portion 50 can combine the low-concentration mixed liquid, the high-concentration mixed liquid, and the new liquid. The amount of new liquid supplied to the merging tank Tk2 can be adjusted, for example, using the new liquid valve 57.

[0198] As mentioned above, Figure 4 In the example, the low-concentration mixed liquid flows into the confluence tank Tk2 through the recovery pipe 51A (equivalent to the first pipe), the high-concentration mixed liquid flows through the recovery pipe 51B (equivalent to the third pipe), and the new liquid flows through the new liquid pipe 56 (equivalent to the second pipe).

[0199] Figure 4 In the example shown in FIG2 , the merging portion 50 further includes a concentration sensor Sn5. The concentration sensor Sn5 measures the solvent concentration of the merging mixed liquid in the merging tank Tk2 and outputs the measurement result to the control unit 6. The concentration sensor Sn5 may be a conductivity-type concentration sensor, an optical concentration sensor, or an ultrasonic concentration sensor.

[0200] The control unit 6 can control the new liquid valve 57 based on the solvent concentration measured by the concentration sensor Sn5. Specifically, when the solvent concentration is low, the control unit 6 can open the new liquid valve. This allows new liquid to be supplied to the merging tank Tk2 via the new liquid piping 56. The solvent concentration of the combined mixed liquid in the merging tank Tk2 increases as the amount of new liquid flowing in increases. Therefore, the merging unit 50 can more reliably generate a combined mixed liquid having a solvent concentration greater than the reference concentration value.

[0201] It should be noted that the supply amounts of the low-concentration mixed liquid, the high-concentration mixed liquid, and the new liquid can be adjusted respectively by the recovery valve 52A, the recovery valve 52B, and the new liquid valve 57. Therefore, the recovery valve 52A, the recovery valve 52B, and the new liquid valve 57 can function as a regulator 59 that adjusts the confluence ratio of the low-concentration mixed liquid, the high-concentration mixed liquid, and the new liquid.

[0202] Figure 1 and Figure 4 In the example of FIG, the upstream end portion of the liquid feeding pipe 53 is connected to, for example, the bottom portion of the junction tank Tk2. Figure 1 In the example of FIG, a liquid feed valve 54 and a pump 55 as an example of a liquid feed unit are inserted into the liquid feed pipe 53. When the controller 6 opens the liquid feed valve 54 and operates the pump 55, the combined mixed liquid in the combining tank Tk2 passes through the liquid feed pipe 53 and is supplied to the first dehydrator 60.

[0203] <3-1-1. First Dehydrator>

[0204] Figure 5 It is a diagram schematically showing an example of the first dehydrator 60 . Figure 5 In the example of , the first dehydrator 60 includes a concentration tank Tk1 and a first circulation unit 61 .

[0205] (a) Concentration tank Tk1

[0206] Figure 5 In this example, the downstream end of the liquid supply pipe 53 is connected to the concentration tank Tk1. The combined mixed liquid is supplied from the confluence portion 50 via the liquid supply pipe 53 to the concentration tank Tk1. The concentration tank Tk1 stores the combined mixed liquid. As described above, the solvent concentration of the combined mixed liquid is equal to or greater than the lower limit of the concentration of the first separation membrane 62c.

[0207] (b) First circulation unit 61

[0208] The first circulation section 61 includes a first membrane separator 62 and a first circulation pipe 63. The first circulation pipe 63 is connected to the concentration tank Tk1. The first circulation pipe 63 is a pipe that returns the combined mixed liquid from the concentration tank Tk1 to the concentration tank Tk1. In other words, the first circulation pipe 63 forms a first circulation path that circulates the combined mixed liquid stored in the concentration tank Tk1 so that it flows out of the concentration tank Tk1 and returns to the concentration tank Tk1. Figure 5 In the example of , the upstream end of the first circulation pipe 63 is connected to the bottom of the concentration tank Tk1 , and the downstream end of the first circulation pipe 63 is connected to the upper part of the concentration tank Tk1 .

[0209] The first membrane separator 62 is installed in the first circulation piping 63. Specifically, the first mixing path 62a of the first membrane separator 62 is inserted into the first circulation piping 63, forming part of the first circulation path of the first circulation section 61. Therefore, the combined mixed liquid passes through the first mixing path 62a. A portion of the water in the combined mixed liquid that flows into the first mixing path 62a passes through the first separation membrane 62c and flows into the first water path 62b. Due to this dehydration, the solvent concentration of the combined mixed liquid immediately after passing through the first membrane separator 62 in the first circulation piping 63 becomes higher than the solvent concentration of the combined mixed liquid immediately before passing through the first membrane separator 62. Since the first circulation section 61 circulates the combined mixed liquid through the first circulation piping 63, the combined mixed liquid continuously flows into the first membrane separator 62. Therefore, the first membrane separator 62 continuously separates water from the combined mixed liquid. As a result, the solvent concentration of the circulating combined mixed liquid increases over time. Hereinafter, the liquid separated from the mixed liquid by the first membrane separator 62 is also referred to as a separated liquid. The separated liquid is mostly water.

[0210] The first separation membrane 62c can be a zeolite membrane, an organic separation membrane or a CNT (carbon nanotube) separation membrane. For example, the zeolite membrane has a tetrahedral structure (SiO4). 4- and (AlO4) 5-A crystal structure connected to each other. Examples of organic separation membranes are organic membranes such as polyvinyl alcohol, chitosan, and polyimide. Examples of CNT separation membranes are membranes obtained by adding carbon nanotubes to membranes such as polyamide. Alternatively, a two-dimensional material can be used as the material for the first separation membrane 62c. A two-dimensional material is a material composed of one layer of atoms, for example, molybdenum sulfide (MoS2), or a composite atomic layer compound formed by a pre-periodic transition metal (titanium, vanadium, etc.) and a light element (carbon or nitrogen). Alternatively, MOF (Metal Organic Frameworks) materials or carbon materials (for example, graphene or graphene oxide) can be used as the material for the first separation membrane 62c. Here, a zeolite membrane is used as the first separation membrane 62c.

[0211] The upstream end of the separation discharge pipe 66 is connected to the first water path 62b. The separation liquid is discharged to the outside (for example, to a waste liquid treatment unit of a factory device) through the separation discharge pipe 66. A pressure reducing pump for reducing the pressure of the first water path 62b may be provided in the separation discharge pipe 66. Figure 5 As shown, a discharge valve 67 is inserted into the separation discharge pipe 66 .

[0212] Figure 5 In the example, the first circulation section 61 includes, in addition to the first membrane separator 62 and the first circulation pipe 63 , a pump 64 as an example of a liquid feeding section, a first switching valve 651 , and a second switching valve 652 .

[0213] The pump 64 is inserted into the first circulation pipe 63. As an example, the pump 64 is installed upstream of the first membrane separator 62. The first switching valve 651 and the second switching valve 652 are inserted into the first circulation pipe 63. The first switching valve 651 is installed downstream of the first membrane separator 62. The second switching valve 652 is installed upstream of the pump 64.

[0214] Various sensors can be inserted into the first circulation piping 63. For example, a concentration sensor Sn63 for measuring the concentration of the organic solvent (here, for example, IPA) in the fluid flowing through the first circulation piping 63, a flow sensor (flow meter) Sn64 for measuring the flow rate of the fluid flowing through the first circulation piping 63, and a pressure sensor Sn61 for measuring the pressure of the fluid flowing through the first circulation piping 63 are inserted into the first circulation piping 63. The concentration sensor Sn63 is inserted, for example, downstream of the first membrane separator 62. The flow sensor Sn64 is inserted, for example, upstream of the pump 64. The pressure sensor Sn61 is inserted, for example, downstream of the pump 64 and upstream of the first membrane separator 62.

[0215] <3-1-2. Recyclable Liquid Supply Unit 89>

[0216] Figure 5 In the example of FIG, the first dehydrator 60 further includes a reused liquid supply unit 89. The reused liquid supply unit 89 supplies the reused liquid to the supply tank Tk3. The reused liquid supply unit 89 includes a liquid supply pipe 85, a liquid supply valve 861 (see FIG. Figure 1 ), liquid delivery valve 862 (see Figure 1 ), and a pump 64 as an example of a liquid delivery unit.

[0217] Figure 5 In the example, the supply tank Tk3 is connected to the first circulation pipe 63 via the liquid supply pipe 85. That is, the downstream end of the liquid supply pipe 85 is connected to the supply tank Tk3, and the upstream end of the liquid supply pipe 85 is connected to the first circulation pipe 63. Specifically, the upstream end of the liquid supply pipe 85 is connected to the first circulation pipe 63 at a position between the pump 64 and the first switching valve 651. As an example, the upstream end of the liquid supply pipe 85 is connected to the first circulation pipe 63 at a position between the pump 64 and the first membrane separator 62. It should be noted that the upstream end of the liquid supply pipe 85 does not necessarily have to be connected to the first circulation pipe 63, and can also be connected to the concentration tank Tk1. In this case, a pump other than the pump 64 is provided in the liquid supply pipe 85.

[0218] <3-2. Example of Operation of the Organic Solvent Recovery Unit 5>

[0219] Figure 6 This is a flowchart illustrating an example of the operation of the organic solvent recovery unit 5. First, the merging unit 50 merges the low-concentration mixed liquid and the high-concentration mixed liquid to produce a merged mixed liquid (step S1: merging step). Specifically, the control unit 6 opens the recovery valve 52A and the recovery valve 52B. This allows the low-concentration mixed liquid from the substrate processing apparatus 100A and the high-concentration mixed liquid from the substrate processing apparatus 100B to be supplied to the merging tank Tk2. The merging unit 50 merges the low-concentration mixed liquid and the high-concentration mixed liquid to produce a merged mixed liquid having a concentration greater than a reference value.

[0220] As described above, it is also conceivable that the solvent concentration of the mixed liquid after merging is less than the concentration reference value due to insufficient high-concentration mixed liquid. For this reason, the merging section 50 can also merge new liquid. First, the concentration sensor Sn5 measures the solvent concentration of the merging mixed liquid in the merging tank Tk2 and outputs its measurement result to the control section 6. In addition, the control section 6 compares the solvent concentration measured by the concentration sensor Sn5 with the first concentration reference value. The first concentration reference value can be the same as the lower concentration limit value of the first separation membrane 62c (i.e., the concentration reference value), or it can be higher than the lower concentration limit value. In addition, the first concentration reference value is less than the reuse reference value, for example, it is set to a value closer to the lower concentration limit value than the reuse reference value. When the solvent concentration is less than the first concentration reference value, the control section 6 opens the new liquid valve 57. As a result, new liquid with a high solvent concentration is supplied to the merging section 50, and the new liquid is supplied to the merging tank Tk2. Therefore, the solvent concentration of the merging mixed liquid increases. The concentration sensor Sn5 may measure the solvent concentration of the merged mixed liquid at predetermined intervals, for example. When the solvent concentration measured by the concentration sensor Sn5 is equal to or greater than a first concentration reference value, the control unit 6 closes the new liquid valve 57 .

[0221] In short, the control unit 6 controls the new liquid valve 57 so that the new liquid is supplied to the merging portion 50 in an amount such that the solvent concentration of the merging mixed liquid is greater than or equal to the concentration reference value. Thus, the organic solvent recovery unit 5 can more reliably store the merging mixed liquid having a solvent concentration greater than or equal to the concentration reference value in the merging tank Tk2.

[0222] Then, the merging portion 50 supplies the merged mixed liquid to the first dehydrator 60. Specifically, the controller 6 opens the liquid feed valve 54 and operates the pump 55. As a result, the merged mixed liquid in the merging tank Tk2 is supplied to the first dehydrator 60. Figure 5 In the example of , the combined mixed liquid is supplied to the concentration tank Tk1.

[0223] Next, the first dehydrator 60 separates water from the confluent mixed liquid, further increasing the solvent concentration of the confluent mixed liquid (step S2: dehydration process). Specifically, the first circulation section 61 allows the confluent mixed liquid to pass through the first circulation pipe 63 and circulate. As an example, the control unit 6 opens the first switching valve 651, the second switching valve 652 and the discharge valve 67, and operates the pump 64. Thus, the confluent mixed liquid circulates in the first circulation path including the concentration tank Tk1 and the first circulation pipe 63. Based on this circulation, the confluent mixed liquid continues to pass through the first membrane separator 62. Therefore, the first membrane separator 62 continues to separate the separation liquid from the confluent mixed liquid, and the separation liquid continues to pass through the separation discharge pipe 66 and be discharged to the outside. Therefore, the solvent concentration of the confluent mixed liquid in the circulation increases over time.

[0224] The controller 6 circulates the combined mixed liquid in the first circulation section 61 until the solvent concentration of the circulating combined mixed liquid reaches or exceeds a predetermined reuse reference value. The reuse reference value may be, for example, 60 wt% or greater, 70 wt% or greater, 80 wt% or greater, 90 wt% or greater, 95 wt% or greater, or 99 wt% or greater. For example, when the solvent concentration measured by the concentration sensor Sn63 is compared with the reuse reference value and the solvent concentration exceeds the reuse reference value, the controller 6 may stop the circulation in the first circulation section 61. Specifically, the controller 6 closes the first switching valve 651, the second switching valve 652, and the discharge valve 67, thereby stopping the pump 64.

[0225] Based on this circulation, the combined mixed liquid (i.e., the reused liquid) with an increased solvent concentration is stored in the concentration tank Tk1. It should be noted that the controller 6 may also use the passage of a predetermined first dehydration time as a trigger to stop the circulation of the first circulation unit 61. The first dehydration time is, for example, pre-set to a time period longer than that required for the solvent concentration to reach a reuse reference value or higher. The first dehydration time can be set, for example, to several tens of minutes or more or several hours or more.

[0226] Next, the reused liquid supply unit 89 supplies the reused liquid to the supply tank Tk3 (step S3: supply process: third process). Specifically, the control unit 6 opens the liquid supply valve 861 or the liquid supply valve 862 and activates the pump 64. This allows the reused liquid in the concentration tank Tk1 to pass through at least the liquid supply pipe 85 and be supplied to the supply tank Tk3 of the substrate processing apparatus 100A or 100B.

[0227] As described above, the organic solvent recovery unit 5 increases the solvent concentration of the mixed liquid from the treatment unit 4 and supplies the mixed liquid to the supply tank Tk3 as a reuse liquid.

[0228] In the above example, the first dehydrator 60 increases the solvent concentration of the combined mixed liquid by repeatedly flowing it into the first membrane separator 62 through circulation in the first circulation section 61. Furthermore, the increase in solvent concentration in the first membrane separator 62 increases as the size of the first membrane separator 62 (i.e., the size of the first separation membrane 62c) increases. Therefore, if the first dehydrator 60 does not circulate the combined mixed liquid, the size of the first membrane separator 62 would need to be increased to ensure a sufficient increase in solvent concentration. In contrast, in the above specific example, the first dehydrator 60 increases the solvent concentration of the combined mixed liquid through circulation in the first circulation section 61. Therefore, the size of the first membrane separator 62 (i.e., the size of the first separation membrane 62c) required to raise the solvent concentration of the mixed liquid to a reuse reference value can be reduced.

[0229] It should be noted that while both the confluence tank Tk2 and the concentrator Tk1 are provided in the above example, this is not necessarily the case. A low-concentration mixed liquid and a high-concentration mixed liquid may also be supplied to the concentrator Tk1. Specifically, the downstream end of the confluence pipe 518 may be connected to the concentrator Tk1. In this case, the concentrator Tk1 also functions as the confluence tank Tk2.

[0230] In the above example, the low-concentration mixed liquid from the substrate processing apparatus 100A and the high-concentration mixed liquid from the substrate processing apparatus 100B flow into the merging tank Tk2. However, this is not necessarily limited to this. For example, the low-concentration mixed liquid may flow into the merging tank Tk2 via the recovery pipe 51A (equivalent to the first pipe), and the new liquid may flow into the merging tank Tk2 via the new liquid pipe 56 (equivalent to the second pipe). In other words, the recovery pipe 51B may not be connected to the merging tank Tk2.

[0231] <Second embodiment>

[0232] Figure 7 Schematically shows an example of a merging portion 50 according to the second embodiment. The merging portion 50 according to the second embodiment includes a first merging tank Tk21 , a second merging tank Tk22 , a recovery destination switching portion 500 , and a supply source switching portion 550 .

[0233] The recovery destination switching unit 500 switches the recovery destinations of the low-concentration mixed liquid from the substrate processing apparatus 100A and the high-concentration mixed liquid from the substrate processing apparatus 100B between the first merging tank Tk21 and the second merging tank Tk22 .

[0234] Figure 7 In the example of FIG. 5 , the recovery destination switching unit 500 includes a recovery pipe 51 and a switching valve unit 520 . Figure 7 In the figure, the recovery pipe 51A is shown as the recovery pipe 51 for the substrate processing apparatus 100A, and the switching valve unit 520A is shown as the switching valve unit 520 for the substrate processing apparatus 100A. Furthermore, the recovery pipe 51B is shown as the recovery pipe 51 for the substrate processing apparatus 100B, and the switching valve unit 520B is shown as the switching valve unit 520 for the substrate processing apparatus 100B.

[0235] The recovery pipe 51A includes a common recovery pipe 510A, a first branch pipe 511A, and a second branch pipe 512A. The common recovery pipe 510A is connected to the substrate processing apparatus 100A. Specifically, the downstream ends of the cup-side recovery pipes 424 of the substrate processing apparatus 100A are connected to the common recovery pipe 510A. Therefore, the low-concentration mixed liquid flows into the common recovery pipe 510A. The downstream end of the common recovery pipe 510A is connected to the upstream end of the first branch pipe 511A and the upstream end of the second branch pipe 512A. The downstream end of the first branch pipe 511A is connected to the first merging tank Tk21, and the downstream end of the second branch pipe 512A is connected to the second merging tank Tk22.

[0236] Figure 7 In the example shown in FIG. 1 , the switching valve unit 520A includes a switching valve 521A and a switching valve 522A. The switching valve unit 520A switches between a state in which the common recovery pipe 510A is connected to the first merging tank Tk21 via the first branch pipe 511A and a state in which the common recovery pipe 510A is connected to the second merging tank Tk22 via the second branch pipe 512A. Figure 7 In the example of FIG, the switching valve 521A is inserted into the first branch pipe 511A, and the switching valve 522A is inserted into the second branch pipe 512A.

[0237] When the controller 6 opens the switching valve 521A, the low-concentration mixed liquid from the substrate processing apparatus 100A is supplied to the first merging tank Tk21. On the other hand, when the controller 6 opens the switching valve 522A, the low-concentration mixed liquid from the substrate processing apparatus 100A is supplied to the second merging tank Tk22.

[0238] The recovery pipe 51B and the switching valve unit 520B are identical to the recovery pipe 51A and the switching valve unit 520A, respectively. For example, the recovery pipe 51B includes a common recovery pipe 510B, a first branch pipe 511B, and a second branch pipe 512B, which are identical to the common recovery pipe 510A, the first branch pipe 511A, and the second branch pipe 512A, respectively. However, the common recovery pipe 510B is connected to the substrate processing apparatus 100B. Figure 7 In the example of FIG. 5 , the switching valve portion 520B includes a switching valve 521B and a switching valve 522B, which are the same as the switching valve 521A and the switching valve 522A, respectively.

[0239] When the controller 6 opens the switching valve 521B, the high-concentration mixed liquid from the substrate processing apparatus 100B is supplied to the first merging tank Tk21. On the other hand, when the controller 6 opens the switching valve 522B, the high-concentration mixed liquid from the substrate processing apparatus 100B is supplied to the second merging tank Tk22.

[0240] Figure 7 In the example, a new liquid switching unit 580 for switching the supply destination of the new liquid between the first merging tank Tk21 and the second merging tank Tk22 is provided at the merging portion 50. The new liquid switching unit 580 includes a new liquid piping 56 and a switching valve unit 570. The new liquid piping 56 includes a common new liquid piping 560, a first branch pipe 561, and a second branch pipe 562. The upstream end of the common new liquid piping 560 is connected to the new liquid supply source. The downstream end of the common new liquid piping 560 is connected to the upstream end of the first branch pipe 561 and the upstream end of the second branch pipe 562. The downstream end of the first branch pipe 561 is connected to the first merging tank Tk21, and the downstream end of the second branch pipe 562 is connected to the second merging tank Tk22.

[0241] Figure 7 In the example shown in FIG. 5 , the switching valve unit 570 includes a switching valve 571 and a switching valve 572. The switching valve unit 570 switches between a state in which the common fresh liquid pipe 560 is connected to the first merging tank Tk21 via the first branch pipe 561 and a state in which the common fresh liquid pipe 560 is connected to the second merging tank Tk22 via the second branch pipe 562. Figure 7 In the example of FIG, the switching valve 571 is inserted into the first branch pipe 561 , and the switching valve 572 is inserted into the second branch pipe 562 .

[0242] When the control unit 6 opens the switching valve 571, new liquid is supplied to the first merging tank Tk21. On the other hand, when the control unit 6 opens the switching valve 572, new liquid is supplied to the second merging tank Tk22.

[0243] Figure 7 In the example of , the organic solvent recovery unit 5 includes a first measurement circulation unit 81 and a second measurement circulation unit 82. The first measurement circulation unit 81 measures the solvent concentration of the merged mixed liquid in the first merging tank Tk21. Figure 7 In the example shown, the first measurement circulation unit 81 includes a first measurement circulation pipe 811, a switching valve 821, a pump 831, and a concentration sensor Sn51. The first measurement circulation pipe 811 returns the mixed liquid from the first merging tank Tk21 to the first merging tank Tk21. Specifically, the mixed liquid circulates through the first measurement circulation path including the first merging tank Tk21 and the first measurement circulation pipe 811. Figure 7In this example, the upstream end of the first measurement circulation pipe 811 is connected to the bottom of the first merging tank Tk21, and the downstream end of the first measurement circulation pipe 811 is connected to the top of the first merging tank Tk21. A switching valve 821 and a pump 831 are inserted into the first measurement circulation pipe 811. The switching valve 821 is located downstream of the pump 831. The concentration sensor Sn51 measures the solvent concentration of the mixed liquid flowing through the first measurement circulation pipe 811. An example of the configuration of the concentration sensor Sn51 is the same as that of the concentration sensor Sn5.

[0244] While the first measurement circulation unit 81 circulates the combined mixed liquid through the first measurement circulation path, the concentration sensor Sn51 measures the solvent concentration of the combined mixed liquid. This measured value can be said to represent the solvent concentration of the combined mixed liquid in the first joining tank Tk21.

[0245] The second measurement circulation unit 82 measures the solvent concentration of the combined mixed liquid within the second converging tank Tk22. An example of the configuration of the second measurement circulation unit 82 is similar to that of the first measurement circulation unit 81. Specifically, the second measurement circulation unit 82 includes a second measurement circulation pipe 812, a switching valve 822, a pump 832, and a concentration sensor Sn52. These components are similar to the first measurement circulation pipe 811, the switching valve 821, the pump 831, and the concentration sensor Sn51, respectively. However, the second measurement circulation pipe 812 is connected to the second converging tank Tk22.

[0246] The supply source switching unit 550 switches the supply source for supplying the combined mixed liquid to the first dehydrator 60 between the first combining tank Tk21 and the second combining tank Tk22 . Figure 7 In the example shown in FIG. 5 , the supply source switching unit 550 includes a liquid supply pipe 53 and a switching valve unit 540. The liquid supply pipe 53 includes a common liquid supply pipe 530, a first branch pipe 531, and a second branch pipe 532. The downstream end of the common liquid supply pipe 530 is connected to the first dehydrator 60. The upstream end of the common liquid supply pipe 530 is connected to the downstream end of the first branch pipe 531 and the downstream end of the second branch pipe 532. Figure 7 In the example, the upstream end of the first branch pipe 531 is connected to the first measurement circulation pipe 811 between the switching valve 821 and the pump 831, and the upstream end of the second branch pipe 532 is connected to the second measurement circulation pipe 812 between the switching valve 822 and the pump 832.

[0247] It should be noted that the upstream end of the first branch pipe 531 may be connected to the first confluence tank Tk21, and the upstream end of the second branch pipe 532 may be connected to the second confluence tank Tk22. In this case, a pump (not shown) is inserted into each of the first branch pipe 531 and the second branch pipe 532.

[0248] Figure 7 In the example of FIG, the switching valve unit 540 includes a liquid feeding valve 541 and a liquid feeding valve 542. The switching valve unit 540 switches between a state in which the first merging tank Tk21 communicates with the first dehydrator 60 and a state in which the second merging tank Tk22 communicates with the first dehydrator 60. Figure 7 In the example of FIG, the liquid delivery valve 541 is inserted into the first branch pipe 531 , and the liquid delivery valve 542 is inserted into the second branch pipe 532 .

[0249] When the controller 6 opens the liquid feed valve 541 and operates the pump 831, the combined mixed liquid from the first merging tank Tk21 is supplied to the first dehydrator 60. On the other hand, when the controller 6 opens the liquid feed valve 542 and operates the pump 832, the combined mixed liquid from the second merging tank Tk22 is supplied to the first dehydrator 60.

[0250] Figure 8 This diagram illustrates an example of the operation of the organic solvent recovery unit 5 according to the second embodiment. First, the recovery destination switching unit 500 selects the first merging tank Tk21 as the recovery destination for the mixed liquid. Specifically, the control unit 6 opens the switching valves 521A and 521B. Consequently, the low-concentration mixed liquid from the substrate processing apparatus 100A and the high-concentration mixed liquid from the substrate processing apparatus 100B are supplied to the first merging tank Tk21. In other words, the low-concentration mixed liquid and the high-concentration mixed liquid are recovered in the first merging tank Tk21. Consequently, the storage volume of the mixed liquid in the first merging tank Tk21 increases over time.

[0251] For example, when the storage volume of the mixed liquid in the first merging tank Tk21 exceeds a predetermined storage reference value, the control unit 6 causes the recovery destination switching unit 500 to switch the recovery destination. The storage volume can be measured, for example, by a sensor (not shown) (e.g., a liquid level sensor) and output to the control unit 6. For example, when the storage volume measured by the sensor exceeds the storage volume reference value, the control unit 6 closes the switching valves 521A and 521B and opens the switching valves 522A and 522B. As a result, the low-concentration mixed liquid from the substrate processing apparatus 100A and the high-concentration mixed liquid from the substrate processing apparatus 100B are recovered in the second merging tank Tk22. Therefore, the storage volume of the mixed liquid in the second merging tank Tk22 increases over time.

[0252] During the process of recovering the mixed liquid using the second confluence tank Tk22, the control unit 6 confirms the solvent concentration of the confluent mixed liquid in the first confluence tank Tk21. Specifically, first, the control unit 6 opens the switching valve 821 and operates the pump 831. As a result, the mixed liquid circulates in the first measurement circulation path. In addition, the concentration sensor Sn51 measures the solvent concentration of the circulating mixed liquid and outputs its measurement result to the control unit 6. The control unit 6 compares the measured solvent concentration with the first concentration reference value. When the solvent concentration is above the first concentration reference value, the control unit 6 closes the switching valve 821, opens the liquid supply valve 541, and supplies the confluent mixed liquid in the first confluence tank Tk21 to the first dehydrator 60.

[0253] On the other hand, when the solvent concentration is less than the concentration reference value, the controller 6 opens the switching valve 571 to supply new liquid to the first merging tank Tk21. This increases the solvent concentration of the combined mixed liquid in the first merging tank Tk21. Furthermore, when the solvent concentration measured by the concentration sensor Sn51 exceeds the first concentration reference value, the controller 6 closes the switching valve 571. Next, the controller 6 closes the switching valve 821 and opens the liquid supply valve 541 to supply the combined mixed liquid in the first merging tank Tk21 to the first dehydrator 60. As a result, the amount of combined mixed liquid stored in the first merging tank Tk21 decreases over time, for example, reaching almost zero.

[0254] When the storage amount of the mixed liquid in the second merging tank Tk22 exceeds the storage reference value, the control unit 6 switches the recovery destination by the recovery destination switching unit 500. As a result, the low-concentration mixed liquid and the high-concentration mixed liquid are recovered again in the first merging tank Tk21.

[0255] While the mixed liquid is being recovered through the first confluence tank Tk21, the control unit 6 confirms the solvent concentration of the mixed liquid within the second confluence tank Tk22 based on the operation of the second measurement circulation unit 82. The operation of the second measurement circulation unit 82 is identical to that of the first measurement circulation unit 81. Furthermore, as needed, the organic solvent recovery unit 5 opens the switching valve 572 to supply new liquid to the second confluence tank Tk22 and then opens the liquid supply valve 542 to supply the combined mixed liquid within the second confluence tank Tk22 to the first dehydrator 60. This causes the second confluence tank Tk22 to become nearly empty, for example. The operations of the switching valve 572 and the liquid supply valve 542 are identical to those of the switching valve 571 and the liquid supply valve 541, respectively.

[0256] As described above, in the second embodiment, while the mixed liquid is being recovered in one of the first merging tank Tk21 and the second merging tank Tk22, the solvent concentration of the combined mixed liquid in the other merging tank is adjusted as needed, and then the combined mixed liquid is supplied from the other merging tank to the first dehydrator 60. Therefore, a low-concentration mixed liquid or a high-concentration mixed liquid is not supplied to the merging tank during solvent concentration adjustment. Therefore, the solvent concentration can be adjusted more reliably.

[0257] The recovery destination of the mixed liquid is alternately switched between the first merging tank Tk21 and the second merging tank Tk22. Therefore, the organic solvent recovery unit 5 can constantly recover the low-concentration mixed liquid and the high-concentration mixed liquid through the merging tank that does not perform concentration adjustment.

[0258] In addition, in the above example, when measuring the solvent concentration of the merged mixed liquid in the first merging tank Tk21, the merged mixed liquid circulates in the first measurement circulation path. Therefore, the merged mixed liquid in the first merging tank Tk21 is stirred, and the concentration distribution of the mixed liquid is made more uniform. The same is true for the second merging tank Tk22. It can also be said that the first measurement circulation section 81 and the second measurement circulation section 82 are stirring circulation sections. Through this stirring, the merging section 50 can supply a mixed liquid with a more uniform concentration distribution to the first dehydrator 60. If the concentration distribution of the mixed liquid is uneven, the mixed liquid with a low solvent concentration can instantly flow into the first separation membrane 62c. In the above example, since the merging section 50 can make the concentration distribution more uniform, the possibility of the mixed liquid with a low solvent concentration instantly flowing into the first separation membrane 62c can be reduced.

[0259] <Third embodiment>

[0260] In the first and second embodiments, a low-concentration mixed liquid is discharged from the substrate processing apparatus 100A, and a high-concentration mixed liquid is discharged from the substrate processing apparatus 100B. However, since the solvent concentration of the mixed liquid depends on the processing content of each processing unit 4, it is also conceivable that a high-concentration mixed liquid or a low-concentration mixed liquid can be discharged from the same substrate processing apparatus 100. In the third embodiment, it is considered to provide an organic solvent recovery unit 5 that can cope with such a situation.

[0261] Figure 9 Schematically shows an example of the organic solvent recovery unit 5 according to the third embodiment. Figure 9As shown, the organic solvent recovery unit 5 involved in the third embodiment includes a low concentration tank Tk2L and a high concentration tank Tk2H. The low concentration tank Tk2L stores a mixed liquid having a solvent concentration less than a concentration reference value. The high concentration tank Tk2H stores a mixed liquid having a solvent concentration greater than a concentration reference value. In the third embodiment, the organic solvent recovery unit 5 switches the recovery destination of the mixed liquid from the substrate processing apparatus 100 between the low concentration tank Tk2L and the high concentration tank Tk2H according to the level of the solvent concentration. Furthermore, the organic solvent recovery unit 5 merges the low concentration mixed liquid from the low concentration tank Tk2L with the high concentration mixed liquid from the high concentration tank Tk2H to generate a merged mixed liquid having a solvent concentration greater than the concentration reference value.

[0262] Figure 9 In the example of the embodiment, the organic solvent recovery unit 5 includes a first recovery destination switching unit 500A and a second recovery destination switching unit 500B. The first recovery destination switching unit 500A switches the recovery destination of the mixed liquid from the substrate processing apparatus 100A between the low-concentration tank Tk2L and the high-concentration tank Tk2H. That is, the first recovery destination switching unit 500A switches between a first low-concentration state in which the substrate processing apparatus 100A is connected to the low-concentration tank Tk2L and a first high-concentration state in which the substrate processing apparatus 100A is connected to the high-concentration tank Tk2H. Similar to the second embodiment, the first recovery destination switching unit 500A includes a recovery pipe 51A and a switching valve unit 520A. However, the downstream end of the first branch pipe 511A of the recovery pipe 51A is connected to the low-concentration tank Tk2L, and the downstream end of the second branch pipe 512A of the recovery pipe 51A is connected to the high-concentration tank Tk2H.

[0263] The control unit 6 controls the first recovery destination switching unit 500A according to the solvent concentration of the mixed liquid from the substrate processing apparatus 100A. Figure 9 In the example, a concentration sensor Sn5A is provided in the common recovery pipe 510A. The concentration sensor Sn5A measures the solvent concentration of the mixed liquid flowing through the common recovery pipe 510A and outputs the measurement result to the control unit 6. An example of the configuration of the concentration sensor Sn5A is the same as that of the concentration sensor Sn5. When the solvent concentration of the mixed liquid measured by the concentration sensor Sn5A is less than the concentration reference value, for example, the control unit 6 causes the first recovery destination switching unit 500A to select the first low concentration state. Specifically, the control unit 6 opens the switching valve 521A and closes the switching valve 522A. As a result, the mixed liquid from the substrate processing apparatus 100A is recovered in the low concentration tank Tk2L.

[0264] On the other hand, when the solvent concentration of the mixed liquid measured by concentration sensor Sn5A is greater than the concentration reference value, the control unit 6 causes the first recovery destination switching unit 500A to select the first high-concentration state. Specifically, the control unit 6 closes switching valve 521A and opens switching valve 522A. As a result, the mixed liquid from the substrate processing apparatus 100A is recovered in the high-concentration tank Tk2H.

[0265] For example, the concentration sensor Sn5A may measure the solvent concentration of the mixed liquid at predetermined intervals and output the measurement results to the control unit 6. As described above, the control unit 6 controls the first recovery destination switching unit 500A based on the solvent concentration. In this case, the first recovery destination switching unit 500A can switch the recovery destination based on the solvent concentration of the mixed liquid, which fluctuates over time. Specifically, while a mixed liquid with a low solvent concentration is being discharged from the substrate processing apparatus 100A, the mixed liquid is recovered in the low-concentration tank Tk2L. While a mixed liquid with a high solvent concentration is being discharged from the substrate processing apparatus 100A, the mixed liquid is recovered in the high-concentration tank Tk2H.

[0266] The second recovery destination switching unit 500B switches the recovery destination of the mixed liquid from the substrate processing apparatus 100B between the low-concentration tank Tk2L and the high-concentration tank Tk2H. That is, the second recovery destination switching unit 500B switches between a second low-concentration state in which the substrate processing apparatus 100B is connected to the low-concentration tank Tk2L and a second high-concentration state in which the substrate processing apparatus 100B is connected to the high-concentration tank Tk2H. Similar to the second embodiment, the second recovery destination switching unit 500B includes a recovery pipe 51B and a switching valve unit 520B. However, the downstream end of the first branch pipe 511B of the recovery pipe 51B is connected to the low-concentration tank Tk2L, and the downstream end of the second branch pipe 512B of the recovery pipe 51B is connected to the high-concentration tank Tk2H.

[0267] The control unit 6 controls the second recovery destination switching unit 500B according to the solvent concentration of the mixed liquid from the substrate processing apparatus 100B. Figure 9 In the example of FIG, a concentration sensor Sn5B is provided in the common recovery pipe 510B. An example of the configuration of the concentration sensor Sn5B is similar to that of the concentration sensor Sn5. Similar to the first recovery destination switching unit 500A, the control unit 6 controls the second recovery destination switching unit 500B based on the solvent concentration measured by the concentration sensor Sn5B.

[0268] Figure 9In the example of , similar to the second embodiment, the organic solvent recovery unit 5 includes a first measurement circulation unit 81 and a second measurement circulation unit 82. However, the first measurement circulation unit 81 measures the solvent concentration of the low-concentration mixed liquid in the low-concentration tank Tk2L, and the second measurement circulation unit 82 measures the solvent concentration of the high-concentration mixed liquid in the high-concentration tank Tk2H.

[0269] The control unit 6 determines the confluence ratio of the low-concentration mixed liquid and the high-concentration mixed liquid based on the solvent concentration of the low-concentration mixed liquid in the low-concentration tank Tk2L and the solvent concentration of the high-concentration mixed liquid in the high-concentration tank Tk2H. Specifically, the control unit 6 determines the confluence ratio so that the solvent concentration of the confluence mixed liquid is greater than the concentration reference value. The control unit 6 may also determine the supply amounts of the low-concentration mixed liquid and the high-concentration mixed liquid to the confluence section 50 based on the confluence ratio. For example, the total amount of the mixed liquid supplied to the confluence section 50 is pre-set, and the control unit 6 determines the supply amounts based on this total amount and the confluence ratio.

[0270] The organic solvent recovery unit 5 further includes a regulator 90. The regulator 90 adjusts the merging ratio between the low-concentration mixed liquid supplied from the low-concentration tank Tk2L to the merging unit 50 and the high-concentration mixed liquid supplied from the high-concentration tank Tk2H to the merging unit 50. Figure 9 In the example of , the regulator 90 includes a liquid supply pipe 51L (equivalent to a first pipe), a liquid supply pipe 51H (equivalent to a second pipe), an adjustment valve 52L, an adjustment valve 52H, a pump 831 , and a pump 832 .

[0271] Liquid supply pipe 51L connects low-concentration tank Tk2L to junction 50 (specifically, junction tank Tk2), while liquid supply pipe 51H connects high-concentration tank Tk2H to junction 50 (specifically, junction tank Tk2). Adjustment valve 52L is inserted into liquid supply pipe 51L, while adjustment valve 52H is inserted into liquid supply pipe 51H.

[0272] When the controller 6 opens the regulating valve 52L and operates the pump 831, the low-concentration mixed liquid is supplied from the low-concentration tank Tk2L via the liquid supply pipe 51L to the merging tank Tk2. The amount of the low-concentration mixed liquid supplied to the merging tank Tk2 is adjusted based on the closing time of the regulating valve 52L or the stopping time of the pump 831. When the controller 6 opens the regulating valve 52H and operates the pump 832, the high-concentration mixed liquid is supplied from the high-concentration tank Tk2H via the liquid supply pipe 51H to the merging tank Tk2. The amount of the high-concentration mixed liquid supplied to the merging tank Tk2 is adjusted based on the closing time of the regulating valve 52H or the stopping time of the pump 832.

[0273] The upstream end of the liquid supply pipe 51L can be connected to the low concentration tank Tk2L, and the upstream end of the liquid supply pipe 51H can be connected to the high concentration tank Tk2H. In this case, a pump (not shown) is inserted into each of the liquid supply pipes 51L and 51H.

[0274] However, in order to make the solvent concentration of the merged mixed liquid equal to or higher than the concentration reference value, the storage amount of the high-concentration mixed liquid in the high-concentration tank Tk2H may be insufficient. Figure 9 In the example, a new liquid pipe 56 is also provided. Figure 9 As shown, the downstream end of the fresh liquid pipe 56 is connected to the junction tank Tk2. A fresh liquid valve 57 is inserted into the fresh liquid pipe 56.

[0275] In this case, the regulator 90 adjusts the confluence ratio of the low-concentration mixed liquid flowing through the liquid supply pipe 51L, the high-concentration mixed liquid flowing through the liquid supply pipe 51H, and the fresh liquid flowing through the fresh liquid pipe 56. The regulator 90 includes, for example, a regulating valve 52L, a regulating valve 52H, and a fresh liquid valve 57.

[0276] Figure 10 This is a flowchart showing an example of the operation of the organic solvent recovery unit 5 according to the third embodiment. Figure 10 An example of the operation of each of the first collection destination switching unit 500A and the second collection destination switching unit 500B is mainly shown.

[0277] Figure 10 A series of processing is repeatedly executed at predetermined intervals, for example. Figure 10 As shown, first, the concentration sensor Sn5A measures the solvent concentration of the mixed liquid flowing through the common recovery pipe 510A (step S11: concentration acquisition step).

[0278] Next, the control unit 6 determines whether the solvent concentration measured by the concentration sensor Sn5A is above a concentration reference value (step S12: concentration determination step). If the solvent concentration is above the concentration reference value, the control unit 6 causes the first recovery destination switching unit 500A to select the high-concentration tank Tk2H as the recovery destination (step S13: high-concentration tank step). Specifically, the control unit 6 opens the switching valve 522A while the switching valve 521A is closed. This allows the high-concentration mixed liquid to be recovered in the high-concentration tank Tk2H.

[0279] On the other hand, if the solvent concentration is less than the concentration reference value in step S12, the control unit 6 causes the first recovery destination switching unit 500A to select the low-concentration tank Tk2L as the recovery destination (step S14: low-concentration tank step). Specifically, the control unit 6 opens switching valve 521A and closes switching valve 522A. As a result, the low-concentration mixed liquid is recovered in low-concentration tank Tk2L.

[0280] Figure 11 This is a flowchart showing an example of the operation of the organic solvent recovery unit 5 according to the third embodiment. Figure 11 An example of the operation of the adjuster 90 is mainly shown.

[0281] First, the concentration sensor Sn51 measures the solvent concentration of the low-concentration mixed liquid in the low-concentration tank Tk2L (step S21: low-concentration acquisition process). Specifically, the control unit 6 first opens the switching valve 821 and activates the pump 831. This causes the low-concentration mixed liquid to circulate through the first measurement circulation path. The concentration sensor Sn51 measures the solvent concentration of the circulating low-concentration mixed liquid and outputs the measurement result to the control unit 6. When the measurement is completed, the control unit 6 closes the switching valve 821 and stops the pump 831.

[0282] Next, the concentration sensor Sn5B measures the solvent concentration of the high-concentration mixed liquid in the high-concentration tank Tk2H (step S22: high concentration acquisition process). Specifically, first, the control unit 6 opens the switching valve 822 and operates the pump 832. As a result, the high-concentration mixed liquid circulates in the second measurement circulation path. The concentration sensor Sn52 measures the solvent concentration of the circulating high-concentration mixed liquid and outputs its measurement results to the control unit 6. When the measurement is completed, the control unit 6 closes the switching valve 822 and stops the pump 832. It should be noted that step S22 can be performed in parallel with step S21, or before step S21.

[0283] Next, the control unit 6 determines the supply amounts of the low-concentration mixed liquid and the high-concentration mixed liquid to the merging portion 50 based on the solvent concentrations of the low-concentration mixed liquid and the high-concentration mixed liquid (step S23: supply amount determination step). Specifically, the control unit 6 determines each supply amount so that the solvent concentration of the merging mixed liquid is greater than or equal to a concentration reference value. As an example, the total supply amount (target value) of the low-concentration mixed liquid and the high-concentration mixed liquid and the solvent concentration (target value) of the merging mixed liquid are pre-set, and the control unit 6 calculates each supply amount so that the total supply amount and the solvent concentration of the merging mixed liquid reach the target values.

[0284] When at least one of the storage amount of the low-concentration mixed liquid in the low-concentration tank Tk2L and the storage amount of the high-concentration mixed liquid in the high-concentration tank Tk2H is insufficient, the control unit 6 may determine the insufficient amount as the supply amount of the new liquid.

[0285] Next, the regulator 90 supplies the low-concentration mixed liquid and the high-concentration mixed liquid to the merging section 50 according to the respectively calculated supply amounts (step S24: merging process). In step S23, when the supply amount of the new liquid is determined, the regulator 90 supplies the low-concentration mixed liquid, the high-concentration mixed liquid and the new liquid to the merging section 50 according to the respectively calculated supply amounts. As an example, the control unit 6 opens the adjustment valve 52L and the adjustment valve 52H to operate the pumps 831 and 832. The control unit 6 controls the closing time points of the adjustment valves 52L and 52H, and the stopping time points of the pumps 831 and 832 based on their respective supply amounts. In addition, as needed, the control unit 6 controls the new liquid valve 57 to supply the new liquid to the merging tank Tk2. The control unit 6 adjusts the closing time point of the new liquid valve 57 based on the calculated supply amount of the new liquid. As a result, the merging mixed liquid with a concentration above the reference value is more reliably stored in the merging tank Tk2.

[0286] As described above, in the third embodiment, the mixed liquid from the substrate processing apparatus 100A and the substrate processing apparatus 100B is distributed to the low-concentration tank Tk2L and the high-concentration tank Tk2H based on the solvent concentration of the mixed liquid. Furthermore, the organic solvent recovery unit 5 supplies the mixed liquid from the low-concentration tank Tk2L and the high-concentration tank Tk2H, as well as new liquid as needed, to the merging unit 50 at a supply rate sufficient to ensure that the solvent concentration of the combined mixed liquid is at least the reference concentration value. Therefore, the merging unit 50 can more reliably ensure that the solvent concentration of the combined mixed liquid is at least the reference concentration value.

[0287] In the above example, a plurality of substrate processing apparatuses 100 are connected to the organic solvent recovery unit 5. Therefore, the amount of the mixed liquid recovered in the low-concentration tank Tk2L and the high-concentration tank Tk2H increases, thereby suppressing the shortage of the mixed liquid.

[0288] It should be noted that a single substrate processing apparatus 100 may be connected to the organic solvent recovery unit 5. In this case, the mixed liquid from the substrate processing apparatus 100 is also distributed to the low-concentration tank Tk2L and the high-concentration tank Tk2H according to its solvent concentration. The organic solvent recovery unit 5 supplies the low-concentration mixed liquid, the high-concentration mixed liquid, and, if necessary, new liquid at their respective supply rates to the merging unit 50 to generate a merging mixed liquid having a concentration greater than a reference value.

[0289] <Fourth embodiment>

[0290] Figure 12 It is a diagram schematically showing an example of a substrate processing system 1000 according to the fourth embodiment. Figure 12In the example of , the organic solvent recovery unit 5 is connected to a single substrate processing apparatus 100. In this case, one processing unit 4 in the substrate processing apparatus 100 corresponds to the first processing unit, and the other processing unit 4 corresponds to the second processing unit. The organic solvent recovery unit 5 according to the fourth embodiment is different from the organic solvent recovery unit 5 according to the third embodiment in that it includes a recovery destination switching unit 500. In the fourth embodiment, the switching valve unit 520 of the recovery destination switching unit 500 is provided for each processing unit 4. In addition, Figure 12 In the example of FIG. 5 , the recovery pipe 51 includes a low-concentration pipe 511 , a high-concentration pipe 512 , and a plurality of cup-side recovery pipes 424 . The upstream end of each cup-side recovery pipe 424 is connected to the corresponding processing unit 4 .

[0291] The downstream end of the low-concentration pipe 511 is connected to the low-concentration tank Tk2L. In addition, the low-concentration pipe 511 is connected to the downstream end of each cup-side recovery pipe 424. Figure 12 In the example shown, the low-concentration piping 511 includes a first common piping 513 and a plurality of first branch pipes 514. The plurality of first branch pipes 514 are provided one-to-one with the plurality of cup-side recovery pipes 424. The upstream ends of the first branch pipes 514 are connected to the downstream ends of the corresponding cup-side recovery pipes 424, and the downstream ends of the first branch pipes 514 are connected to the first common piping 513. The downstream end of the first common piping 513 corresponds to the downstream end of the low-concentration piping 511.

[0292] The downstream end of the high-concentration pipe 512 is connected to the high-concentration tank Tk2H. In addition, the high-concentration pipe 512 is connected to the downstream end of each cup-side recovery pipe 424. Figure 12 In the example shown, the high-concentration piping 512 includes a second common piping 515 and a plurality of second branch pipes 516. The plurality of second branch pipes 516 are provided one-to-one with the plurality of cup-side recovery pipes 424. The upstream ends of the second branch pipes 516 are connected to the downstream ends of the corresponding common recovery pipes 510, and the downstream ends of the second branch pipes 516 are connected to the second common piping 515. The downstream end of the second common piping 515 corresponds to the downstream end of the high-concentration piping 512.

[0293] Figure 12 In the example, the switching valve unit 520 includes a switching valve 521 and a switching valve 522. The switching valve unit 520 switches between a state where the cup-side recovery pipe 424 communicates with the low-concentration tank Tk2L and a state where the cup-side recovery pipe 424 communicates with the high-concentration tank Tk2H. Figure 12 In the example, the plurality of switching valve sections 520 are provided one to one with respect to the plurality of processing units 4. That is, Figure 12In the example, the plurality of switching valves 521 are provided one-to-one with the plurality of processing units 4, and the plurality of switching valves 522 are provided one-to-one with the plurality of processing units 4. Each switching valve 521 is inserted into the corresponding first branch pipe 514, and each switching valve 522 is inserted into the corresponding second branch pipe 516.

[0294] The following describes the operation of the switching valve unit 520 associated with a single processing unit 4. When the controller 6 closes the switching valve 521 and opens the switching valve 522, the mixed liquid from the processing unit 4 sequentially flows through the cup-side recovery pipe 424 and the high-concentration pipe 512 and is supplied to the high-concentration tank Tk2H. When the controller 6 opens the switching valve 521 and closes the switching valve 522, the mixed liquid from the processing unit 4 sequentially flows through the cup-side recovery pipe 424 and the low-concentration pipe 511 and is supplied to the low-concentration tank Tk2L.

[0295] The control unit 6 controls the recovery destination switching unit 500 based on the solvent concentration of the mixed liquid discharged from the processing unit 4. Specifically, the control unit 6 controls the recovery destination switching unit 500 to select the low-concentration tank Tk2L as the recovery destination when the solvent concentration of the mixed liquid is at least the concentration reference value, and controls the recovery destination switching unit 500 to select the high-concentration tank Tk2H as the recovery destination when the solvent concentration of the mixed liquid is less than the concentration lower limit value.

[0296] An example of the operation of the recovery destination switching unit 500 is similar to Figure 10 However, in the fourth embodiment, as described below, in step S11 , the control unit 6 may calculate the solvent concentration of the mixed liquid from the processing unit 4 based on the processing content of the processing unit 4 .

[0297] <Calculation of Solvent Concentration Based on Process Information>

[0298] Here, an example of a method for obtaining the solvent concentration of the mixed liquid discharged from the processing unit 4 is described. The solvent concentration of the mixed liquid discharged from the processing unit 4 depends on the processing content of the substrate W by the processing unit 4. For example, the processing unit 4 supplies pure water to the substrate W and then supplies an organic solvent to the substrate W. In this process, if the processing unit 4 supplies pure water to the substrate W at a large flow rate and for a long time, the solvent concentration of the mixed liquid discharged from the processing unit 4 becomes relatively low. On the other hand, if the processing unit 4 supplies an organic solvent to the substrate W at a large flow rate and for a long time, the solvent concentration of the mixed liquid discharged from the processing unit 4 becomes relatively high. In this way, the solvent concentration of the mixed liquid discharged from the processing unit 4 depends on the processing content.

[0299] Figure 13 Schematically shows an example of the processing unit 4 according to the fourth embodiment. Figure 13As shown, the control unit 6 is connected to a storage unit 603. The storage unit 603 is, for example, a nonvolatile storage unit, specifically a memory or a hard disk. The storage unit 603 stores process information D1 that specifies the processing details for the substrate W. The process information D1 includes various information such as the nozzle used in each process, the flow rate of the processing liquid, the discharge time of the processing liquid, and the rotation speed of the substrate W.

[0300] In addition, if Figure 13 As shown, the processing unit 4 may include a plurality of cups 42 . Figure 13 In the example of FIG, a cup body 42A, a cup body 42B, and a cup body 42C are shown as the plurality of cup bodies 42. The cup body 42A, the cup body 42B, and the cup body 42C are provided concentrically. Figure 13 In the example, cup body 42A is located at the outermost side, cup body 42C is located at the innermost side, and cup body 42B is located between cup body 42A and cup body 42C.

[0301] The cup-body lifting mechanism 425 raises and lowers each cup 42. For example, the cup-body lifting mechanism 425 raises the cup 42A to the upper position and lowers the cup 42B and the cup 42C to the lower position. In this state, the processing liquid scattered from the periphery of the substrate W is blocked by the cup 42A. In addition, the cup-body lifting mechanism 425 raises the cup 42A and the cup 42B to the upper position and lowers the cup 42C to the lower position. In this state, the processing liquid scattered from the periphery of the substrate W is blocked by the cup 42B. In addition, the cup-body lifting mechanism 425 raises the cup 42A, the cup 42B, and the cup 42C to the upper position. In this state, the processing liquid scattered from the periphery of the substrate W is blocked by the cup 42C.

[0302] Figure 13 In the example shown in FIG. 5 , the processing liquid blocked by the cup 42C flows into the recovery pipe 51. The processing liquid blocked by the cup 42A flows into another recovery pipe (not shown), and the processing liquid blocked by the cup 42B flows into another recovery pipe (not shown).

[0303] Such a processing unit 4 can change the cup body 42 that blocks the processing liquid according to the type of processing liquid. For example, when supplying pure water to the substrate W, the cup body lifting mechanism 425 only places the cup body 42A in the upper position. In this case, the pure water is blocked by the cup body 42A. In addition, when supplying an organic solvent to the substrate W, the cup body lifting mechanism 425 places the cup bodies 42A to 42C in the upper position. In this case, the organic solvent is blocked by the cup body 42C and flows into the recovery pipe 51. That is, in this example, the cup body 42C is a cup body for organic solvent, and the recovery pipe 51 is a recovery pipe for organic solvent. In this way, the processing unit 4 can switch the cup body to be used between the cup body 42A to the cup body 42C according to the type of processing liquid. Information indicating the position of the cup body 42 in each of these processes is also included in the process information D1.

[0304] like Figure 13 As shown, the control unit 6 includes a concentration estimating unit 601. The concentration estimating unit 601 reads the process information D1 from the storage unit 603. Based on the process information D1, the concentration estimating unit 601 calculates the solvent concentration of the mixed liquid discharged from the processing unit 4 (i.e., the mixed liquid flowing into the recovery pipe 51). Table 1 schematically illustrates a first example of the process information D1.

[0305] [Table 1]

[0306] Process Information

[0307]

[0308] Table 1 shows some of the steps involved in processing a substrate W. In Table 1, process information D1 includes the number of each step, the rotation speed of the substrate W during each step, the time required for each step, the flow rate of the processing liquid during each step, the type of processing liquid during each step, and the cup used during each step. The cup used can be considered as information indicating the position of the cup 42.

[0309] Figure 14 This is a diagram schematically showing an example of the state of the processing unit 4 in each step of Table 1. Figure 14 (a) to Figure 14 (f) in FIG. 1 shows an example of the state of the processing unit 4 in the 30th step to the 35th step in Table 1.

[0310] In the 30th step of Table 1, the spin chuck 41 rotates the substrate W at 100 rpm for 2 seconds, and the rinse liquid nozzle 43b sprays pure water at 2000 mL (milliliter) / min toward the substrate W. In addition, in the 30th step, the cup 42A is used. Figure 14 As shown in (a) in FIG. 1 , in the 30th step, pure water scattered from the periphery of the substrate W is blocked by the cup 42A.

[0311] In the 31st step, the spin chuck 41 rotates the substrate W at 10 rpm for 1 second. In the 31st step, no processing liquid is supplied to the substrate W. In the 31st step, since the rotation speed of the substrate W is low, Figure 14 As shown in (b) of Table 1, pure water is maintained on the main surface of the substrate W. This process is also called a immersion treatment. Although not shown in Table 1, the following process can be performed between steps 30 and 31: the rinse liquid nozzle 43b sprays pure water at 2000 mL / min, while the chuck 41 is rotated to gradually reduce the rotation speed to 10 rpm. The lower the rotation speed of the substrate W after stopping the pure water spray, the thicker the pure water film on the main surface of the substrate W during the immersion treatment.

[0312] In the 32nd step, the spin chuck 41 rotates the substrate W at 10 rpm for 1 second, and the cup lifting mechanism 425 switches the cup 42A to the cup 42C (see FIG. Figure 14 (c) in the figure.

[0313] In the 33rd step, the spin chuck 41 rotates the substrate W at 10 rpm for 4 seconds, and the IPA nozzle 43c sprays an organic solvent at 100 mL / min toward the main surface of the substrate W. The organic solvent is, for example, IPA. Figure 14 As shown in (d) in FIG. 33 , in the thirty-third step, the processing liquid (pure water and organic solvent) flows down from the periphery of the substrate W. In this case, the processing liquid is blocked by the cup 42C and flows into the upstream end of the recovery pipe 51 .

[0314] In the 34th step, the spin chuck 41 rotates the substrate W at 1000 rpm for 3 seconds, and the IPA nozzle 43c sprays the organic solvent toward the main surface of the substrate W at 100 mL / min. Figure 14 As shown in (e) in FIG. 3 , the organic solvent that has landed on the main surface of the substrate W flows radially outward and, along with the pure water, scatters outward from the periphery of the substrate W. The mixture of the organic solvent and pure water is trapped by the cup 42C and flows into the upstream end of the recovery pipe 51. Through steps 33 and 34, the pure water on the main surface of the substrate W is replaced with the organic solvent.

[0315] In the 35th step, the spin chuck 41 rotates the substrate W at 1000 rpm for 2 seconds. In the 35th step, no processing liquid is supplied to the substrate W. Figure 14 As shown in (f) in FIG. 35 , in step 35 , a portion of the organic solvent on the main surface of the substrate W is scattered from the periphery of the substrate W. In addition, a remaining portion of the organic solvent is evaporated. Thus, the main surface of the substrate W is dried.

[0316] As described above, the cup body 42C is raised to the upper position in the 31st step (see also Figure 14 (c) in the figure). Therefore, cup 42C can retain the process liquid (pure water and organic solvent, i.e., a mixed liquid) during steps 31 to 35. This process liquid flows into the upstream end of recovery pipe 51. Hereinafter, the period from steps 31 to 35 will also be referred to as the discharge period. The discharge period is the period during which cup 42C can retain the process liquid.

[0317] The solvent concentration (average value) of the mixed liquid flowing into recovery pipe 51 during the discharge period can be calculated based on the pure water discharge rate and solvent discharge rate, as described below. The pure water discharge rate is the total amount of pure water flowing into recovery pipe 51 during the discharge period, that is, the total amount of pure water retained by cup 42C during the discharge period. The solvent discharge rate is the total amount of organic solvent flowing into recovery pipe 51 during the discharge period, that is, the total amount of organic solvent retained by cup 42C during the discharge period.

[0318] First, the pure water discharge amount is described. In the example of Table 1, pure water is not supplied during the discharge period (31st to 35th steps). Therefore, the pure water discharge amount is the amount of pure water present on the main surface of the substrate W at the start time of the 31st step (see also Figure 14 (c) in the figure). Hereinafter, this amount of pure water will be referred to as the pure water film amount. Since the thickness of the pure water film on the main surface of substrate W depends on the rotation speed of substrate W at the start time of step 31, the pure water film amount depends on the rotation speed. It should be noted that the start time of step 31 can also be said to be the start time of switching from cup body 42A to cup body 42C.

[0319] Figure 15 Graphs are examples of graphs showing the distance from each position on the substrate W to the center of the substrate W and the thickness of the pure water liquid film at each position. That is, each graph shows the profile of the pure water liquid surface. Figure 15 Graphs G1 to G4 are shown, each showing different rotation speeds for the substrate W. Graph G1 shows the lowest rotation speed, 10 rpm. Graph G2 shows the next lowest rotation speed, 50 rpm. Graph G3 shows the highest rotation speed, 100 rpm. Graph G4 shows the highest rotation speed, 200 rpm. Graphs G1 to G4 can be obtained through simulation or experimentation.

[0320] The amount of pure water (pure water film amount) present on the main surface of the substrate W can be obtained by integrating the thickness of the liquid film in each graph. Therefore, the correspondence between the rotation speed of the substrate W and the pure water film amount can be obtained in advance. Correspondence information D2 indicating this correspondence is stored in the storage unit 603 (see also Figure 13 Since the rotation speed at the start time of the 31st step is included in the process information D1, the pure water film amount can be calculated based on the rotation speed and the correspondence relationship information D2.

[0321] It should be noted that this chart may also depend on the pure water flow rate in step 30, prior to the spinning and immersion process. Therefore, a chart may be generated for each flow rate in advance through simulation or experimentation, and the pure water film amount may be calculated based on this chart. In this case, the correspondence information D2 includes the correspondence between the combination of rotation speed and pure water flow rate and the pure water film amount.

[0322] Next, the solvent discharge amount is explained. For simplicity, the solvent discharge amount can be considered to be equal to the discharge amount of the organic solvent supplied to the substrate W during the discharge period. The discharge amount of the organic solvent during the discharge period can be calculated by the time integral value of the solvent flow rate of the organic solvent. That is, the solvent discharge amount can be calculated by the sum of the product of the solvent flow rate of the organic solvent and the required time (discharge time) of each process. In the example of Table 1, the solvent discharge amount is represented by 100×(4+3) / 60. It should be noted that since the organic solvent evaporates, the solvent discharge amount can also be calculated by reducing the time integral value by only a specified proportion in view of the evaporation.

[0323] Table 2 schematically shows a second example of the recipe information D1.

[0324] [Table 2]

[0325] Process Information

[0326]

[0327] Table 2 also shows some steps in the processing of the substrate W. Figure 16 This is a diagram schematically showing an example of the state of the processing unit 4 in each step of Table 2. Figure 16 (a) to Figure 16 (e) in Table 2 shows an example of the state of the processing unit 4 in the 30th step to the 34th step, respectively.

[0328] In the 30th step of Table 2, the spin chuck 41 rotates the substrate W at 1500 rpm for 4 seconds, and the rinse liquid nozzle 43b sprays pure water at 2000 mL / min toward the substrate W. In addition, in the 30th step, the cup 42A is used. Figure 16 As shown in (a) in FIG. 1 , in the 30th step, pure water scattered from the periphery of the substrate W is blocked by the cup 42A.

[0329] In the 31st step, the spin chuck 41 rotates the substrate W at 1500 rpm for 2 seconds, and the rinse liquid nozzle 43b sprays pure water at 2000 mL / min toward the substrate W. In addition, in the 31st step, the cup body lifting mechanism 425 switches the cup body to be used from the cup body 42C to the cup body 42A (see Figure 16 (b) in FIG. 1 ). As a result, the pure water is blocked by the cup body 42C and flows into the upstream end of the recovery pipe 51.

[0330] In the 32nd step, the spin chuck 41 rotates the substrate W at 1500 rpm for 0.2 seconds, and the rinse liquid nozzle 43b sprays pure water at 2000 mL / min toward the substrate W, and the IPA nozzle 43c sprays an organic solvent at 250 mL / min toward the substrate W. Figure 16 As shown in (c) in FIG. 1 , in the 32nd step, the processing liquid scattered from the periphery of the substrate W is also blocked by the cup 42C.

[0331] In the 33rd step, the spin chuck 41 rotates the substrate W at 1500 rpm for 30 seconds, and the IPA nozzle 43c sprays the organic solvent toward the main surface of the substrate W at 250 mL / min. Figure 16 As shown in (d) in FIG. 33 , in the 33rd step, the processing liquid scattering from the periphery of the substrate W is also blocked by the cup 42C. Through the 32nd and 33rd steps, the pure water on the main surface of the substrate W is replaced with the organic solvent.

[0332] In the 34th step, the spin chuck 41 rotates the substrate W at 1500 rpm for 30 seconds. In the 34th step, no processing liquid is supplied to the substrate W. Figure 16 As shown in (e) in FIG. 34 , in the 34th step, the cup 42C also blocks the organic solvent scattered from the periphery of the substrate W. In the 34th step, the substrate W is dried.

[0333] As described above, during steps 31 through 34, the cup 42C blocks the processing liquid (pure water and organic solvent) that scatters from the periphery of the substrate W. This processing liquid flows into the upstream end of the recovery pipe 51. Hereinafter, the period from steps 31 through 34 in Table 2 is referred to as the discharge period.

[0334] In Table 2, during steps 31 and 32, the rinse liquid nozzle 43b sprays pure water toward the substrate W. Therefore, the pure water discharge rate is the sum of the amount of pure water present on the main surface of the substrate W at the start of step 31 (i.e., the pure water film amount) and the total amount of pure water sprayed from the rinse liquid nozzle 43b during the discharge period (hereinafter referred to as the pure water discharge rate). It should be noted that the start of step 31 can also be considered the time when the cup 42A is switched to the cup 42C.

[0335] As described above, the amount of the pure water film depends on the rotation speed of the substrate W. Figure 17 1 is a graph showing an example of the distance between each position on the substrate W and the center of the substrate W and the thickness of the liquid film at each position. Figure 17 Graph G5 is shown in FIG. The rotation speed of the substrate W corresponding to graph G5 is 1500 rpm. Information on the amount of pure water film when the rotation speed of the substrate W is 1500 rpm is included in the correspondence information D2.

[0336] It should be noted that this chart can also be based on the pure water flow rate in the 30th step, before the cup switching step. Therefore, a chart can be pre-derived for each flow rate and used to calculate the pure water film amount. In this case, the correspondence information D2 includes a correspondence between the combination of rotational speed and pure water flow rate and the pure water film amount.

[0337] The pure water discharge rate is the total amount of pure water discharged onto the substrate W during the discharge period. The pure water discharge rate can be calculated by integrating the pure water flow rate over time. Specifically, the pure water discharge rate can be calculated by summing the product of the pure water flow rate and the required time (discharge time) for each step. In the example in Table 2, the pure water discharge rate is expressed as 2000 × (2 + 0.2) / 60.

[0338] The solvent discharge amount can be considered equal to the amount of organic solvent discharged onto the substrate W during the discharge period. The amount of organic solvent discharged during the discharge period can be calculated by taking the time-integrated value of the solvent flow rate. In the example of Table 2, the amount of pure water discharged is represented by 250 × (0.2 + 30) / 60. It should be noted that the solvent discharge amount can also be calculated by reducing the time-integrated value by a specified percentage.

[0339] Figure 18 3 is a flowchart showing an example of the operation of the concentration estimating unit 601. First, the concentration estimating unit 601 reads the recipe information D1 from the storage unit 603 (step S31: reading step).

[0340] Next, the concentration estimating unit 601 calculates the pure water film amount based on the process information D1 (step S32: pure water film amount calculation process). Specifically, the concentration estimating unit 601 determines the process for starting the use of the cup body 42C (for example, the 31st process in Table 1 or Table 2) based on the process information D1, and determines the rotation speed of the substrate W at the start time of the process based on the process information D1. The concentration estimating unit 601 may determine the rotation speed of the substrate W in the process as the rotation speed of the substrate W at the start time of the process, or may determine the rotation speed of the substrate W in the process before the process. Next, the concentration estimating unit 601 reads the correspondence information D2 from the storage unit 603. And, the concentration estimating unit 601 calculates the pure water film amount based on the determined rotation speed and the correspondence information D2 (see Figure 14 (c) or Figure 16 (b) in the figure.

[0341] It should be noted that when the correspondence information D2 includes the correspondence between the combination of the rotation speed of the substrate W and the pure water flow rate and the pure water film amount, the concentration estimation unit 601 can determine the pure water flow rate before the process of starting the use of the cup body 42C based on the process information D1, and calculate the pure water film amount based on the determined rotation speed and pure water flow rate and the correspondence information D2.

[0342] Furthermore, the concentration estimating unit 601 calculates the total amount of pure water discharged during the discharge period (the pure water discharge amount) based on the process information D1 (step S33: pure water discharge amount calculation step). Specifically, the concentration estimating unit 601 identifies the process in which the cup 42C is used and pure water is discharged based on the process information D1, and calculates the pure water discharge amount during that process by multiplying the pure water flow rate by the required time. Furthermore, the concentration estimating unit 601 calculates the total discharge amount during each process as the pure water discharge amount.

[0343] Furthermore, the concentration estimating unit 601 calculates the total amount of organic solvent discharged during the discharge period (the solvent discharge amount) based on the process information D1 (step S34: solvent discharge amount calculation step). Specifically, the concentration estimating unit 601 identifies the process in which the cup 42C is used and the organic solvent is discharged based on the process information D1, and calculates the discharge amount of the organic solvent in that process by multiplying the solvent flow rate by the required time. Furthermore, the concentration estimating unit 601 calculates the total discharge amount in each process as the solvent discharge amount. Alternatively, the concentration estimating unit 601 can calculate the solvent discharge amount as a value obtained by reducing this total by a predetermined ratio.

[0344] Next, the concentration estimating unit 601 divides the solvent discharge amount by the sum of the pure water film amount, the pure water discharge amount, and the solvent discharge amount to calculate the solvent concentration (step S35 : solvent concentration calculation step).

[0345] As described above, the concentration estimating unit 601 calculates the solvent concentration based on the process information D1 , thereby eliminating the need for a concentration sensor for measuring the solvent concentration and reducing the manufacturing cost of the substrate processing apparatus 100 .

[0346] Furthermore, in the above example, the concentration estimating unit 601 determines the amount of pure water film based on the rotational speed of the substrate W, and calculates the solvent concentration based on the amount of pure water film, the time-integrated value of the pure water flow rate, and the time-integrated value of the organic solvent flow rate. Therefore, the concentration estimating unit 601 can determine the solvent concentration with higher accuracy. When the concentration estimating unit 601 determines the amount of pure water film based on the pure water flow rate and the rotational speed of the substrate W, the solvent concentration can be determined with even higher accuracy.

[0347] It should be noted that the recovery pipe connected to the cup body 42C is sometimes branched into multiple ones depending on the type of processing liquid. For example, when the cup body 42C is used for organic solvents and other first processing liquids, the cup body 42C is connected to the recovery pipe 51 for the organic solvent and the recovery pipe for the first processing liquid. In addition, a switching valve unit is also provided. The switching valve unit connects the pipe for the first processing liquid to the cup body 42C when the first processing liquid is supplied to the substrate W, and connects the recovery pipe 51 to the cup body 42C when the organic solvent is supplied to the substrate W. In this case, multiple discharge ports are set on the cup body 42C. In this case, the discharge port can also be set in the process information D1. In addition, the concentration estimation unit 601 can also determine the process in which the discharge port for the organic solvent (i.e., the recovery pipe 51) is set, and calculate the pure water film amount, the pure water spray amount and the solvent discharge amount in the same way as above.

[0348] <Measurement of Solvent Concentration Using a Concentration Sensor>

[0349] In the above example, the control unit 6 calculates the solvent concentration of the mixed liquid discharged from the processing unit 4 based on the process information D1. However, the present invention is not limited to this. The solvent concentration of the mixed liquid discharged from the processing unit 4 may be measured using a concentration sensor.

[0350] Figure 19 This diagram schematically illustrates a second example of a substrate processing system 1000 according to the fourth embodiment. In this second example, a concentration sensor Sn5 is provided in each cup-side recovery pipe 424. The concentration sensor Sn5 measures the solvent concentration of the mixed liquid flowing through the cup-side recovery pipe 424 and outputs the measurement result to the control unit 6.

[0351] The control unit 6 controls the recovery destination switching unit 500 based on the solvent concentration measured by the concentration sensor Sn5. Specifically, the control unit 6 compares the solvent concentration measured by the concentration sensor Sn5 with a concentration reference value. If the solvent concentration is less than the concentration reference value, the control unit 6 controls the recovery destination switching unit 500 to select the low-concentration tank Tk2L as the recovery destination. If the solvent concentration is greater than the concentration reference value, the control unit 6 controls the recovery destination switching unit 500 to select the high-concentration tank Tk2H as the recovery destination.

[0352] According to the second example, since the concentration sensor Sn5 measures the solvent concentration, the control unit 6 can obtain the solvent concentration of the mixed liquid with higher accuracy. Therefore, the control unit 6 can more appropriately control the recovery destination switching unit 500 and more appropriately supply the mixed liquid to the low-concentration tank Tk2L or the high-concentration tank Tk2H.

[0353] <Fifth embodiment>

[0354] Figure 20It is a diagram schematically showing a first example of the first dehydrator 60 according to the fifth embodiment. Figure 20 In this example, the downstream ends of recovery pipe 51A (equivalent to the first pipe) and recovery pipe 51B (equivalent to the second pipe) are connected to concentrating tank Tk1. In other words, concentrating tank Tk1 also functions as converging tank Tk2. Therefore, concentrating tank Tk1 can be said to be included in converging section 50.

[0355] In the fifth embodiment, as Figure 20 As shown, the first dehydrator 60 further includes a stirring unit 95. The stirring unit 95 stirs the combined mixed liquid within the concentration tank Tk1. This allows the concentration distribution of the combined mixed liquid within the concentration tank Tk1 to be uniform. Note that since the concentration tank Tk1 also functions as the converging tank Tk2, the stirring unit 95 can be considered as being included in the converging unit 50.

[0356] Figure 20 In the example shown, the stirring section 95 includes a bubbler tube 951, an air supply tube 952, and an air supply valve 953. The bubbler tube 951 is located within the concentrator tank Tk1, where it is immersed in the combined mixed liquid. The bubbler tube 951 can extend horizontally, for example. Alternatively, the bubbler tube 951 can be formed with a plurality of discharge ports 951a arranged along its length. In other words, the stirring section 95 includes the discharge ports 951a that open within the concentrator tank Tk1.

[0357] The downstream end of the gas supply pipe 952 is connected to the bubbler pipe 951, and the upstream end of the gas supply pipe 952 is connected to a gas supply source. The gas supply source supplies gas to the upstream end of the gas supply pipe 952. For example, air or an inert gas can be used. For example, a noble gas or nitrogen can be used as the inert gas. A gas supply valve 953 is inserted into the gas supply pipe 952.

[0358] When the controller 6 opens the gas supply valve 953, gas flows from the gas supply pipe 952 into the bubbler pipe 951 and is ejected from the ejection port 951a into the mixed liquid in the concentration tank Tk1. This introduces a plurality of bubbles into the mixed liquid. These bubbles rise within the mixed liquid and are released from the liquid surface. This movement of the bubbles stirs the mixed liquid, thereby achieving a more uniform concentration distribution in the combined mixed liquid within the concentration tank Tk1.

[0359] Figure 21This is a flowchart showing an example of the operation of the organic solvent recovery unit 5 according to the fifth embodiment. First, as in the first to fourth embodiments, the merging unit 50 merges the low-concentration mixed liquid and the high-concentration mixed liquid to generate a merged mixed liquid (step S41: merging process). As an example, the control unit 6 opens the recovery valve 52A and the recovery valve 52B. As a result, the low-concentration mixed liquid from the substrate processing apparatus 100A and the high-concentration mixed liquid from the substrate processing apparatus 100B flow into the concentration tank Tk1. It should be noted that the low-concentration mixed liquid from the substrate processing apparatus 100A may temporarily flow into a low-concentration buffer tank, and the high-concentration mixed liquid from the substrate processing apparatus 100B may temporarily flow into a high-concentration buffer tank.

[0360] Next, the stirring unit 95 stirs the combined mixed liquid in the concentration tank Tk1 (step S42: stirring step). Specifically, the control unit 6 opens the air supply valve 953. This causes the combined mixed liquid in the concentration tank Tk1 to be stirred by a plurality of bubbles. The control unit 6 closes the air supply valve 953, for example, after a predetermined stirring time has elapsed. The stirring time is, for example, pre-set to a time sufficient to achieve a sufficiently uniform concentration distribution in the combined mixed liquid.

[0361] Next, similarly to step S2 , the first dehydrator 60 separates water from the merged mixed liquid to generate a reused liquid (step S43 : dehydration step).

[0362] Next, similarly to step S3 , the first dehydrator 60 supplies the reuse liquid to the supply tank Tk3 (step S44 : supply process).

[0363] As described above, in the fifth embodiment, after stirring the combined mixed liquid to reduce the unevenness of its concentration distribution, the first dehydrator 60 uses the first membrane separator 62 to separate water from the combined mixed liquid. If the concentration distribution of the combined mixed liquid in the concentration tank Tk1 is significantly uneven, a mixed liquid with a low solvent concentration can instantly flow into the first membrane separator 62. In contrast, in the fifth embodiment, a combined mixed liquid with a more uniform concentration distribution flows into the first membrane separator 62. Therefore, the possibility of a mixed liquid with a low solvent concentration flowing into the first membrane separator 62 can be reduced. In other words, the reliability of the organic solvent recovery unit 5 can be further improved.

[0364] Moreover, in the structure for ejecting bubbles into the mixed liquid as described above, there is no mechanical driving part in the mixed liquid. For comparison, a case where a stirring driving part such as a screw is set in the mixed liquid was studied. In this case, since the screw works mechanically in the mixed liquid, particles may be generated due to its friction, etc. Therefore, the concentration of impurities in the mixed liquid increases. In contrast, Figure 20In the example of , since there is no driving unit in the mixed liquid, the generation of particles can be avoided. In other words, the increase in the impurity concentration in the mixed liquid can be avoided.

[0365] Figure 22 It is a diagram schematically showing a second example of the first dehydrator 60 according to the fifth embodiment. Figure 22 In the example shown, the stirring unit 95 includes a stirring circulation pipe 96. The stirring circulation pipe 96 is a circulation pipe that returns the mixed liquid from the concentration tank Tk1 to the concentration tank Tk1. The stirring unit 95 circulates the mixed liquid through the stirring circulation path including the concentration tank Tk1 and the stirring circulation pipe 96, thereby stirring the mixed liquid in the concentration tank Tk1.

[0366] Figure 22 In this example, a portion of the stirring circulation pipe 96 is shared with the first circulation pipe 63. Specifically, the first circulation pipe 63 includes a downstream common pipe 631, an upstream common pipe 632, and a first independent pipe 630, while the stirring circulation pipe 96 includes a downstream common pipe 631, an upstream common pipe 632, and an independent stirring pipe 960. In other words, the downstream common pipe 631 and the upstream common pipe 632 are shared by the first circulation pipe 63 and the stirring circulation pipe 96. The upstream end of the upstream common pipe 632 is connected to the concentration tank Tk1, while the downstream end of the upstream common pipe 632 is connected to the upstream end of the first independent pipe 630 and the upstream end of the independent stirring pipe 960. The downstream end of the downstream common pipe 631 is connected to the concentration tank Tk1, while the upstream end of the downstream common pipe 631 is connected to the downstream end of the first independent pipe 630 and the downstream end of the independent stirring pipe 960.

[0367] The pump 64 and the second switching valve 652 are inserted into the upstream common pipe 632, and the first switching valve 651 is inserted into the downstream common pipe 631. Thus, the pump 64, the first switching valve 651, and the second switching valve 652 are shared by the first circulation section 61 and the stirring section 95. The first membrane separator 62 is installed in the first independent pipe 630. The independent stirring pipe 960 is also a bypass pipe that bypasses the first membrane separator 62.

[0368] The first dehydrator 60 is further provided with a circulation switching unit 69 . Figure 22 In the example shown in FIG. 1 , the circulation switching unit 69 includes a switching valve 691 and a switching valve 692. The circulation switching unit 69 switches between a state in which the downstream common pipe 631 is connected to the upstream common pipe 632 via the first independent pipe 630 and a state in which the downstream common pipe 631 is connected to the upstream common pipe 632 via the independent stirring pipe 960. Figure 22 In the example, the switching valve 691 is inserted into the first independent pipe 630 , and the switching valve 692 is inserted into the independent stirring pipe 960 .

[0369] The operation of the organic solvent recovery unit 5 according to the second example of the fifth embodiment is similar to Figure 21 is the same. However, in step S42 (stirring process), the control unit 6 closes the switching valve 961, opens the first switching valve 651, the second switching valve 652 and the switching valve 692, and operates the pump 64. As a result, the merged mixed liquid passes through the stirring circulation path and circulates. Therefore, the merged mixed liquid in the concentration tank Tk1 is stirred, and the concentration distribution of the merged mixed liquid is more uniform. It should be noted that in this stirring cycle, the merged mixed liquid does not pass through the first membrane separator 62. Therefore, it is possible to avoid the merged mixed liquid with a low solvent concentration caused by uneven concentration distribution from flowing into the first membrane separator 62.

[0370] The controller 6 may also stop stirring the stirring unit 95 when a predetermined stirring time has elapsed. In the next step S43 (dehydration process), the controller 6 closes the switching valve 692 and opens the switching valve 691 and the discharge valve 67. As a result, the combined mixed liquid circulates through the first circulation path and undergoes separation processing.

[0371] As described above, in the second example of the fifth embodiment, after stirring the combined mixed liquid to achieve a more uniform concentration distribution, the first dehydrator 60 uses the first membrane separator 62 to separate water from the combined mixed liquid. This reduces the likelihood of a mixed liquid with a low solvent concentration flowing into the first membrane separator 62. Furthermore, in this second example, compared to a case where a drive mechanism such as a screw is located within the concentration tank Tk1, an increase in the impurity concentration in the mixed liquid can be suppressed. Furthermore, in the above example, since the pump 64 is shared between the first circulation section 61 and the stirring section 95, the manufacturing cost and device size of the organic solvent recovery section 5 can be reduced.

[0372] <Sixth embodiment>

[0373] Figure 23 1 is a diagram showing an example of a substrate processing system 1000 according to a sixth embodiment. The organic solvent recovery unit 5 according to the sixth embodiment differs from the organic solvent recovery units 5 according to the first to fifth embodiments in the presence or absence of a second dehydrator 70 .

[0374] The second dehydrator 70 is provided at a stage before the merging portion 50 . Figure 23In the example, the downstream end of the recovery pipe 51B is connected to the second dehydrator 70. Therefore, the high-concentration mixed liquid from the substrate processing apparatus 100B flows into the second dehydrator 70. The second dehydrator 70 separates water from the high-concentration mixed liquid, thereby increasing the solvent concentration of the high-concentration mixed liquid. For example, if the solvent concentration of the high-concentration mixed liquid discharged from the substrate processing apparatus 100B is approximately 70 wt%, the second dehydrator 70 increases the solvent concentration of the high-concentration mixed liquid by, for example, 10 wt% or more. A specific example of the second dehydrator 70 will be described later. Figure 23 In the example of FIG, the second dehydrator 70 is connected to the upstream end of the liquid feeding pipe 78, and the downstream end of the liquid feeding pipe 78 is connected to the merging portion 50. The second dehydrator 70 supplies the separated high-concentration mixed liquid to the merging portion 50 through the liquid feeding pipe 78.

[0375] The merging unit 50 merges the low-concentration mixed liquid from the substrate processing apparatus 100A with the high-concentration mixed liquid from the second dehydrator 70. Because the second dehydrator 70 increases the solvent concentration of the high-concentration mixed liquid, the merging unit 50 can more reliably maintain the solvent concentration of the combined mixed liquid above a reference concentration value through this merging. In other words, the organic solvent recovery unit 5 can reduce the amount of new liquid used while maintaining the solvent concentration of the combined mixed liquid above the reference concentration value.

[0376] Figure 24 This is a diagram schematically showing a first example of the second dehydrator 70 . Figure 24 In the example shown in FIG. 1 , the second dehydrator 70 includes a distillation column 701 and a cooler 702. The downstream end of the recovery pipe 51B is connected to the distillation column 701, and the upstream end of the steam pipe 7031 is connected to, for example, the upper portion of the distillation column 701. The downstream end of the steam pipe 7031 is connected to the cooler 702.

[0377] The distillation tower 701 includes a heating section (not shown) for heating the mixed liquid. The distillation tower 701 separates water from the mixed liquid by distillation utilizing the difference between the boiling points of the organic solvent and water. Here, as an example, the boiling point of the organic solvent is lower than that of water, and the volatility of the organic solvent is higher than that of water. The organic solvent is, for example, IPA. The distillation tower 701 vaporizes the mixed liquid and supplies vapor containing a large amount of organic solvent to the upstream end of the steam piping 7031. The vapor flowing into the upstream end of the steam piping 7031 contains not only the organic solvent but also water, but its solvent concentration is higher than the solvent concentration before flowing into the distillation tower 701. The vapor passes through the steam piping 7031 and flows into the cooler 702.

[0378] The upstream end of liquid piping 7032 is also connected to cooler 702. Cooler 702 cools and condenses the vapor. Cooler 702 may also include a heat exchanger, for example. The vapor passes through the interior of the heat exchanger. Cooler 702 may include a heat pump cooling source or a Peltier element cooling source to cool the heat exchanger. The vapor loses heat in the heat exchanger and turns into a liquid (i.e., a mixed liquid). This mixed liquid flows into the upstream end of liquid piping 7032. The solvent concentration of this mixed liquid is higher than that of the mixed liquid immediately before entering distillation column 701.

[0379] like Figure 24 As shown, the second dehydrator 70 may include a plurality of distillation towers 701 and a plurality of coolers 702 . Figure 24 In the example of FIG. 7 , a set of a distillation column 701 and a cooler 702 is connected in series. Figure 24 In this example, distillation tower 701 includes distillation tower 701a and distillation tower 701b, and cooler 702a and cooler 702b are shown as cooler 702. The downstream end of recovery pipe 51 is connected to distillation tower 701a, steam pipe 7031 connects distillation tower 701a and cooler 702a, and liquid pipe 7032 connects cooler 702a and distillation tower 701b. Vapor from distillation tower 701a is condensed in cooler 702a to form a mixed liquid, and the mixed liquid from cooler 702a is supplied to distillation tower 701b. The upstream end of steam pipe 7033 is connected to, for example, the upper portion of distillation tower 701b, and the downstream end of steam pipe 7033 is connected to cooler 702b. The vapor from the mixed liquid from distillation tower 701b is cooled and condensed in cooler 702b to form a mixed liquid. The upstream end of the liquid supply pipe 78 is connected to the cooler 702 b , and the mixed liquid from the cooler 702 b passes through the liquid supply pipe 78 and is supplied to the merging portion 50 .

[0380] The second dehydrator 70 may include a pump and a valve (not shown). For example, a liquid delivery valve may be inserted into the liquid delivery pipe 78 , and a pump may be inserted into the liquid delivery pipe 7032 .

[0381] Figure 25 This is a diagram schematically showing a second example of the second dehydrator 70 . Figure 25 In this example, the second dehydrator 70 includes an ultrasonic atomizing separator 704. The downstream end of the recovery pipe 51A, the upstream end of the liquid feeding pipe 78, and the upstream end of the separation and discharge pipe 705 are connected to the ultrasonic atomizing separator 704.

[0382] The mixed liquid passes through recovery pipe 51B and flows into ultrasonic atomizer separator 704. Ultrasonic atomizer separator 704 uses ultrasonic vibrations to atomize the mixed liquid. The mixed liquid mist contains organic solvent mist and water mist. These mists have different mass distributions. For example, organic solvent mist tends to be lighter than water mist. Ultrasonic atomizer separator 704 causes the lighter organic solvent mist to move primarily upward and the heavier water mist to move primarily downward, thereby separating the water from the mixed liquid.

[0383] For example, the ultrasonic atomizing separator 704 includes an atomizing tank, an ultrasonic vibrator, a separation container, and a gas supply unit, all of which are not shown in the figure. The mixed liquid from the recovery pipe 51 flows into the atomizing tank. The ultrasonic vibrator atomizes the mixed liquid in the tank. The mist from the atomizing tank flows into the separation container. The mist contains the mist of the organic solvent and the mist of water. The gas supply unit supplies gas from the lower part of the separation container, so that the light organic solvent mist moves mainly upward and the heavy water mist moves mainly downward. The upstream end of the separation discharge pipe 705 is connected to the lower part of the separation container. Therefore, the water mist from the separation container mainly flows into the separation discharge pipe 705. The upstream end of the liquid supply pipe 78 is connected to the upper part of the separation container. The organic solvent mist passes through the liquid supply pipe 78 and is supplied to the confluence part 50. It should be noted that the tank for converging the organic solvent mist can also be arranged between the separation container and the liquid supply pipe 78.

[0384] Figure 26 This is a diagram schematically showing a third example of the second dehydrator 70 . Figure 26 In the example, the second dehydrator 70 includes a second membrane separator 72. The second membrane separator 72 separates water from the mixed liquid, thereby increasing the solvent concentration of the mixed liquid. The second membrane separator 72 includes a second mixing path 72a, a second water path 72b, and a second separation membrane 72c. The second mixing path 72a, the second water path 72b, and the second separation membrane 72c are similar to the first mixing path 62a, the first water path 62b, and the first separation membrane 62c, respectively.

[0385] A portion of the water in the mixed liquid flowing into the second mixing path 72a passes through the second separation membrane 72c and flows into the second water path 72b. The separated liquid flowing into the second water path 72b passes through the separation discharge pipe 76 and is discharged to the outside (for example, to a wastewater treatment unit of a factory equipment).

[0386] The solvent concentration of the mixed liquid passing through the second mixing path 72a is higher than the solvent concentration of the mixed liquid immediately before flowing into the second mixing path 72a. The second dehydrator 70 uses the second membrane separator 72 to increase the solvent concentration of the mixed liquid to a value above the lower limit of the first separation membrane 62c.

[0387] The lower limit of concentration of the second separation membrane 72c is different from the lower limit of concentration of the first separation membrane 62c. For example, the lower limit of concentration of the second separation membrane 72c is higher than the lower limit of concentration of the first separation membrane 62c. In addition, the lower limit of concentration of the second separation membrane 72c is less than the solvent concentration of the mixed liquid from the substrate processing apparatus 100B. Here, the case where the first separation membrane 62c and the second separation membrane 72c are zeolite membranes will be described. The lower limit of concentration of the zeolite membrane is due to the difference in lattice structure of the zeolite membrane. The difference in lattice structure of the zeolite membrane can be represented by type (also called structure code). For example, zeolite membrane types include LTA type, CHA type, and DDR type. The lower limit of concentration of LTA type zeolite membrane is, for example, approximately 50 wt%, the lower limit of concentration of CHA type zeolite membrane is, for example, approximately 70 wt%, and the lower limit of concentration of DDR type zeolite membrane is, for example, approximately 90 wt%.

[0388] As an example, the second separation membrane 72c is a CHA-type zeolite membrane, and the first separation membrane 62c is an LTA-type zeolite membrane. In this case, the lower limit of the concentration of the second separation membrane 72c is approximately 70 wt%. Here, the solvent concentration of the high-concentration mixed liquid from the substrate processing apparatus 100B is approximately 70 wt% or higher. The lower limit of the concentration of the first separation membrane 62c is approximately 50 wt%. More generally, the first separation membrane 62c is a type 1 zeolite membrane, and the second separation membrane 72c is a type 2 zeolite membrane having a higher lower limit of concentration than the type 1 zeolite membrane.

[0389] Furthermore, the separation constant of the second separation membrane 72c is higher than the separation constant of the first separation membrane 62c. The separation constant here refers to an indicator of the solvent concentration of a mixed liquid after the mixed liquid is circulated under predetermined conditions in a circulation path provided with a membrane separator. These conditions include, for example, the initial value of the solvent concentration of the mixed liquid, the flow rate and temperature during the circulation of the mixed liquid, and the circulation time. The higher the solvent concentration of the mixed liquid after circulation, the greater the separation constant. Conversely, the higher the separation constant, the greater the increase in the solvent concentration of the organic solvent by the membrane separator.

[0390] Figure 26 In the example shown in FIG. 1 , the second dehydrator 70 includes a concentration tank Tk4 and a second circulation unit 71. The second circulation unit 71 includes a second circulation pipe 73, a pump 74, a first switching valve 751, and a second switching valve 752. The concentration tank Tk4, the second circulation pipe 73, the pump 74, the first switching valve 751, and the second switching valve 752 are similar to the concentration tank Tk1, the first circulation pipe 63, the pump 64, the first switching valve 651, and the second switching valve 652, respectively.

[0391] Figure 26In the example of , since the second dehydrator 70 uses the second membrane separator 72 to separate water from the mixed liquid, the second dehydrator 70 can further efficiently increase the solvent concentration of the mixed liquid.

[0392] Figure 26 In the example shown, the second dehydrator 70 further includes a liquid feed pipe 78 and a liquid feed valve 79. The upstream end of the liquid feed pipe 78 is connected to the second circulation pipe 73 between the first switching valve 751 and the pump 74. The liquid feed valve 79 is inserted into the liquid feed pipe 78. Similar to the liquid feed pipe 53, the upstream end of the liquid feed pipe 78 can also be connected to the concentration tank Tk4.

[0393] When the controller 6 opens the first switching valve 751, the second switching valve 752, and the discharge valve 77 and operates the pump 74, the mixed liquid circulates through the second circulation path including the concentration tank Tk4 and the second circulation pipe 73. Since the mixed liquid passes through the second membrane separator 72, the second dehydrator 70 can increase the solvent concentration of the mixed liquid in the concentration tank Tk4.

[0394] The second dehydrator 70 according to the third example can increase the solvent concentration of the mixed liquid with higher efficiency than the second dehydrators 70 according to the first and second examples. Furthermore, if the separation constant of the second separation membrane 72c is greater than the separation constant of the first separation membrane 62c, the second dehydrator 70 can further efficiently increase the solvent concentration of the mixed liquid.

[0395] It should be noted that in the above example, the second dehydrator 70 receives the high-concentration mixed liquid from the substrate processing apparatus 100B, but the present invention is not necessarily limited to this. The second dehydrator 70 can also be connected to the downstream end of the recovery pipe 51A, for example. That is, the second dehydrator 70 can also increase the solvent concentration of the low-concentration mixed liquid from the substrate processing apparatus 100A. As an example, the solvent concentration of the low-concentration mixed liquid from the substrate processing apparatus 100A is 30wt%. The second dehydrator 70 increases the solvent concentration of the low-concentration mixed liquid by, for example, about 10wt%, and supplies the mixed liquid to the confluence section 50. As a result, the organic solvent recovery section 5 can also more reliably generate a confluence mixed liquid having a solvent concentration greater than the concentration reference value. It should be noted that when the second dehydrator 70 includes the second membrane separator 72, a separation membrane having a lower concentration lower limit value than the concentration lower limit value of the first separation membrane 62c is used for the second separation membrane 72c. The lower limit of the concentration of the second separation membrane 72c is set to be lower than the solvent concentration of the low-concentration mixed liquid before separation. On the other hand, when the second dehydrator 70 includes at least one of the distillation tower 701 and the ultrasonic atomizing separator 704, the lower limit of the concentration of the second dehydrator 70 is very low, for example, almost zero. Therefore, the second dehydrator 70 can also be easily applied to low-concentration mixed liquids.

[0396] As described above, the second dehydrator 70, for example, separates water from the mixed liquid flowing through one side of the recovery pipe 51A (equivalent to the first pipe) and the recovery pipe 51B (equivalent to the second pipe), thereby increasing the solvent concentration of the mixed liquid, and the confluence section 50, for example, allows the mixed liquid passing through the other side of the recovery pipe 51A and the recovery pipe 51B to merge with the mixed liquid from the second dehydrator 70.

[0397] <Seventh embodiment>

[0398] Figure 27 This figure schematically illustrates an example of a substrate processing system 1000 according to the seventh embodiment. The organic solvent recovery unit 5 according to the seventh embodiment differs from the organic solvent recovery unit 5 according to the sixth embodiment in the presence or absence of a third dehydrator 700. Furthermore, in the seventh embodiment, the second dehydrator 70 includes a second membrane separator 72.

[0399] The third dehydrator 700 is provided in a stage preceding the second dehydrator 70. The lower limit value of the concentration of the third dehydrator 700 is lower than the lower limit value of the concentration of the second separation membrane 72c. Figure 27 In the example, the third dehydrator 700 is connected to the recovery pipe 51B, and the high-concentration mixed liquid from the substrate processing apparatus 100B is supplied to the third dehydrator 700. Here, the solvent concentration of the high-concentration mixed liquid from the substrate processing apparatus 100B is equal to or greater than the lower limit of the concentration of the second separation membrane 72c. For example, the solvent concentration of the high-concentration mixed liquid is approximately 80 wt%, and the lower limit of the concentration of the second separation membrane 72c is 70 wt%.

[0400] The third dehydrator 700 separates water from the high-concentration mixed liquid from the substrate processing apparatus 100B, and increases the solvent concentration of the high-concentration mixed liquid to a concentration lower limit value or higher than the second separation membrane 72c. Figure 24 The same structure can also have Figure 25 The third dehydrator 700 supplies the separated high-concentration mixed liquid to the second dehydrator 70 through the liquid feeding pipe 780 .

[0401] As in the sixth embodiment, the second dehydrator 70 uses the second membrane separator 72 to separate water from the high-concentration mixed liquid, further increasing the solvent concentration of the high-concentration mixed liquid. For example, the second dehydrator 70 increases the solvent concentration of the high-concentration mixed liquid to 80 wt%. The second dehydrator 70 supplies the separated high-concentration mixed liquid to the merging section 50.

[0402] As described above, in the seventh embodiment, the third dehydrator 700 raises the solvent concentration of the mixed liquid to above the lower concentration limit of the second separation membrane 72c. Therefore, the second dehydrator 70 can use the second membrane separator 72 to further increase the solvent concentration of the mixed liquid with high reliability and efficiency. Furthermore, in the seventh embodiment, the lower concentration limit of the second separation membrane 72c differs from the lower concentration limit of the first separation membrane 62c. Therefore, a separation membrane suitable for the solvent concentration range of the mixed liquid flowing into the second membrane separator 72 can be used. For example, a separation membrane with a higher lower concentration limit than that of the first separation membrane 62c can be used for the second separation membrane 72c. Therefore, a separation membrane with a high lower concentration limit and a high separation constant can be used for the second separation membrane 72c.

[0403] <Eighth embodiment>

[0404] Figure 28 This figure schematically illustrates an example of a substrate processing system 1000 according to an eighth embodiment. The organic solvent recovery unit 5 according to the eighth embodiment differs from the organic solvent recovery unit 5 according to the sixth embodiment in the presence or absence of a third dehydrator 700 and a dehydration switching unit 93. Furthermore, in the eighth embodiment, the second dehydrator 70 includes a second membrane separator 72.

[0405] The third dehydrator 700 is provided at a stage before the merging portion 50. The lower limit value of the concentration of the third dehydrator 700 is lower than the lower limit value of the concentration of the second separation membrane 72c.

[0406] Figure 28 In the example shown in FIG. 1 , the second dehydrator 70 and the third dehydrator 700 are connected to the substrate processing apparatus 100 (here, the substrate processing apparatus 100B) via a dehydration switching unit 93. The dehydration switching unit 93 switches the supply destination of the high-concentration mixed liquid from the substrate processing apparatus 100B between the second dehydrator 70 and the third dehydrator 700. Figure 28 In the example of FIG. 5 , the dehydration switching unit 93 includes a recovery pipe 51B and a switching valve unit 520B. Figure 9 Similarly, the recovery pipe 51B includes a common recovery pipe 510B, a first branch pipe 511B, and a second branch pipe 512B. However, the downstream end of the first branch pipe 511B is connected to the second dehydrator 70, and the downstream end of the second branch pipe 512B is connected to the third dehydrator 700. Figure 9 Similarly, the switching valve unit 520B includes a switching valve 521B and a switching valve 522B. A concentration sensor Sn5B is provided in the common recovery pipe 510B.

[0407] The control unit 6 compares the solvent concentration of the high-concentration mixed liquid from the substrate processing device 100B measured by the concentration sensor Sn5B with the second concentration reference value described below. The second concentration reference value is set to be greater than the lower limit of the concentration of the second separation membrane 72c. When the solvent concentration is greater than the second concentration reference value, the control unit 6 causes the dehydration switching unit 93 to select the second dehydrator 70 as the supply destination. Specifically, the control unit 6 opens the switching valve 521B while the switching valve 522B is closed. As a result, the high-concentration mixed liquid is supplied to the second dehydrator 70. The second dehydrator 70 uses the highly efficient second membrane separator 72 to separate water from the high-concentration mixed liquid, thereby increasing the solvent concentration of the high-concentration mixed liquid. The second dehydrator 70 supplies the separated high-concentration mixed liquid to the confluence section 50 through the liquid supply pipe 78.

[0408] On the other hand, if the solvent concentration is less than the second concentration reference value, the controller 6 causes the dehydration switching unit 93 to select the third dehydrator 700 as the supply destination. Specifically, the controller 6 closes the switching valve 521B and opens the switching valve 522B. This causes the highly concentrated mixed liquid to be supplied to the third dehydrator 700. The third dehydrator 700 separates water from the highly concentrated mixed liquid, increasing the solvent concentration of the highly concentrated mixed liquid. The third dehydrator 700 passes the separated highly concentrated mixed liquid through the liquid supply pipe 780 and supplies it to the confluence unit 50.

[0409] The lower limit of the concentration of the third dehydrator 700 is equal to or lower than the solvent concentration of the high-concentration mixed liquid before separation. Figure 24 The composition can also have Figure 25 Although the energy efficiency of the third dehydrator 700 is lower than that of the second dehydrator 70, the third dehydrator 700 can appropriately separate water from the high-concentration mixed liquid having a solvent concentration lower than the lower limit of the concentration of the second separation membrane 72c, thereby increasing the solvent concentration.

[0410] <Ninth embodiment>

[0411] Figure 29 This figure schematically shows an example of the organic solvent recovery unit 5 according to the ninth embodiment. The organic solvent recovery unit 5 according to the ninth embodiment differs from the organic solvent recovery unit 5 according to the eighth embodiment in the presence or absence of a third dehydrator 700 and a circulation switching unit 790.

[0412] The third dehydrator 700 includes a third circulation unit 710 . The third circulation unit 710 includes a third membrane separator 720 , a third circulation pipe 730 , a pump 74 , and a second switching valve 752 . Figure 29 In the example of FIG, a portion of the second circulation pipe 73 and a portion of the third circulation pipe 730 are shared.

[0413] Figure 29 In this example, the second circulation piping 73 includes a downstream common pipe 731, a second independent pipe 733, and an upstream common pipe 732, which is an example of a common circulation pipe. The third circulation piping 730 includes a downstream common pipe 631, a third independent pipe 734, and an upstream common pipe 732. Specifically, the downstream common pipe 731 and the upstream common pipe 732 are shared by the second circulation piping 73 and the third circulation piping 730. The upstream end of the upstream common pipe 732 is connected to, for example, the bottom of the concentrator tank Tk4, while the downstream end of the downstream common pipe 731 is connected to, for example, the top of the concentrator tank Tk4. The upstream ends of the second and third independent pipes 733 and 734 are connected to the downstream end of the upstream common pipe 732, while the downstream ends of the second and third independent pipes 733 and 734 are connected to the upstream end of the downstream common pipe 731. The concentration tank Tk4 and the second circulation pipe 73 form a second circulation path, and the concentration tank Tk4 and the third circulation pipe 730 form a third circulation path.

[0414] The second membrane separator 72 is installed in the second independent pipe 733, and the third membrane separator 720 is installed in the third independent pipe 734. The third membrane separator 720 separates water from the mixed liquid, thereby increasing the solvent concentration of the mixed liquid. The third membrane separator 720 includes a third mixing path 720a, a third water path 720b, and a third separation membrane 720c. The third mixing path 720a, the third water path 720b, and the third separation membrane 720c are similar to the first mixing path 62a, the first water path 62b, and the first separation membrane 62c, respectively.

[0415] A portion of the water in the mixed liquid flowing into the third mixing path 720a passes through the third separation membrane 720c and flows into the third water path 720b. The separated liquid flowing into the third water path 720b passes through the separation discharge piping 760 and is discharged to the outside (for example, to a wastewater treatment unit of a factory facility). A discharge valve 770 is inserted into the separation discharge piping 760.

[0416] The solvent concentration of the mixed liquid passing through the third mixing channel 720 a is higher than the solvent concentration of the mixed liquid immediately before flowing into the third mixing channel 720 a .

[0417] The concentration lower limit of the third separation membrane 720c is lower than the concentration lower limit of the second separation membrane 72c and is equal to or lower than the solvent concentration of the mixed liquid from the substrate processing apparatus 100B. The second separation membrane 72c and the third separation membrane 720c are, for example, zeolite membranes. Specifically, the second separation membrane 72c is a type 2 zeolite membrane, and the third separation membrane 720c is a type 3 zeolite membrane having a lower concentration lower limit than the type 2 zeolite membrane. Furthermore, the separation constant of the second separation membrane 72c is higher than the separation constant of the third separation membrane 720c.

[0418] Figure 29 In the example of FIG, the pump 74 and the second switching valve 752 are inserted into the upstream common pipe 732. Therefore, the pump 74 and the second switching valve 752 are shared by the second circulation unit 71 and the third circulation unit 710.

[0419] Figure 29 In the example, the circulation switching unit 790 includes a first three-way valve 791 and a second three-way valve 792. The circulation switching unit 790 switches the circulation path between the second circulation path and the third circulation path. Specifically, the circulation switching unit 790 switches the second circulation state and the third circulation state described below. The second circulation state is a state in which the downstream common pipe 731 and the upstream common pipe 732 are connected to each other through the second independent pipe 733. In the second circulation state, the mixed liquid circulates in the second circulation path including the concentration tank Tk4 and the second circulation pipe 73. Therefore, the mixed liquid is separated by the second membrane separator 72 on the second circulation path. That is, the second circulation state is equivalent to a state in which the mixed liquid is supplied to the second dehydrator 70. The third circulation state is a state in which the downstream common pipe 731 and the upstream common pipe 732 are connected to each other through the third independent pipe 734. In the third circulation state, the mixed liquid circulates through the third circulation path including the concentration tank Tk4 and the third circulation pipe 730. Therefore, the mixed liquid is separated by the third membrane separator 720. In other words, the third circulation state corresponds to a state in which the mixed liquid is supplied to the third dehydrator 700.

[0420] Figure 29 In the example, the first three-way valve 791 is connected to the upstream end of the downstream common pipe 731, the downstream end of the second independent pipe 733, and the downstream end of the third independent pipe 734. The first three-way valve 791 switches between a second downstream circulation state in which the downstream common pipe 731 is connected to the second independent pipe 733, and a third downstream circulation state in which the downstream common pipe 731 is connected to the third independent pipe 734. The second three-way valve 792 is connected to the downstream end of the upstream common pipe 732, the upstream end of the second independent pipe 733, and the upstream end of the third independent pipe 734. The second three-way valve 792 switches between a second upstream circulation state in which the upstream common pipe 732 is connected to the second independent pipe 733, and a third upstream circulation state in which the upstream common pipe 732 is connected to the third independent pipe 734.

[0421] When the control unit 6 causes the first three-way valve 791 to select the second downstream circulation state and the second three-way valve 792 to select the second upstream circulation state, the mixed liquid circulates in the second circulation path. In other words, the circulation switching unit 790 selects the second circulation state. When the control unit 6 causes the first three-way valve 791 to select the third downstream circulation state and the second three-way valve 792 to select the third upstream circulation state, the mixed liquid circulates in the third circulation path. In other words, the circulation switching unit 790 selects the third circulation state.

[0422] In the ninth embodiment, the control unit 6 controls the circulation switching unit 790 based on, for example, the solvent concentration of the high-concentration mixed liquid from the substrate processing apparatus 100B. Figure 29 In the example, a concentration sensor Sn5B is provided in the common recovery pipe 510B. The control unit 6 may also control the circulation switching unit 790 based on the solvent concentration of the mixed liquid measured by the concentration sensor Sn5B. Specifically, when the solvent concentration is greater than the second concentration reference value, the control unit 6 causes the circulation switching unit 790 to select the second circulation state. Furthermore, the control unit 6 causes the mixed liquid to circulate in the second circulation unit 71. As an example, the control unit 6 opens the second switching valve 752 and the discharge valve 77 to operate the pump 74. Since the mixed liquid continues to flow into the second membrane separator 72 of the second circulation path, the solvent concentration of the mixed liquid increases over time. The control unit 6 causes the mixed liquid to circulate in the second circulation unit 71 until the solvent concentration of the mixed liquid reaches a specified concentration (for example, 80 wt%).

[0423] On the other hand, when the solvent concentration measured by concentration sensor Sn5B is equal to or greater than the lower limit of the concentration of the third separation membrane 720c and less than the second concentration reference value, the controller 6 causes the circulation switching unit 790 to select the third circulation state. Furthermore, the controller 6 causes the mixed liquid to circulate through the third circulation unit 710. For example, the controller 6 opens the second switching valve 752 and the discharge valve 770 and activates the pump 74. As the mixed liquid continues to flow into the third membrane separator 720 of the third circulation path, the solvent concentration of the mixed liquid increases over time.

[0424] The control unit 6 may circulate the mixed liquid in the third circulation unit 710 until the solvent concentration of the mixed liquid reaches a predetermined concentration (eg, 80 wt %) or higher.

[0425] Alternatively, when the solvent concentration of the mixed liquid reaches or exceeds the lower limit of the concentration of the second separation membrane 72c (e.g., 70 wt%), the controller 6 may stop the circulation of the third circulation unit 710 and start the circulation of the second circulation unit 71. Thus, the second circulation unit 71 can continue to increase the solvent concentration of the mixed liquid. Alternatively, the second circulation unit 71 may circulate the mixed liquid until the solvent concentration of the mixed liquid reaches or exceeds a predetermined concentration (e.g., 80 wt%).

[0426] As described above, in the ninth embodiment, even when the solvent concentration of the mixed liquid is less than the lower concentration limit of the second separation membrane 72c, the third dehydrator 700 uses the highly efficient third membrane separator 720 to separate water from the mixed liquid. Furthermore, when the solvent concentration of the mixed liquid is greater than the lower concentration limit of the second separation membrane 72c, the second dehydrator 700 uses the second separation membrane 72c, which has a higher separation constant than that of the third separation membrane 720c, to separate water from the mixed liquid. Consequently, the organic solvent recovery unit 5 can further efficiently increase the solvent concentration of the mixed liquid.

[0427] As described above, the organic solvent recovery device (organic solvent recovery unit 5), substrate processing system 1000, and organic solvent recovery method have been described in detail. However, the above description is illustrative in all respects and the present invention is not limited thereto. Furthermore, the various modifications described above may be combined and applied as long as they do not conflict with each other. Furthermore, it should be understood that multiple modifications not illustrated are conceivable without departing from the scope of the present invention.

[0428] For example, the organic solvent recovery unit 5 may include a filter to capture impurities in the reused liquid. For example, the organic solvent recovery unit 5 may include a purge tank, a purge circulation pipe connected to the purge tank, and a switching valve, a pump, and a filter inserted into the purge circulation pipe. In this way, the organic solvent recovery unit 5 can supply reused liquid with a low impurity concentration to the supply tank Tk3.

Claims

1. An organic solvent recovery device, comprising: a first pipe through which a mixed liquid containing an organic solvent and water flows from a first processing unit that processes a substrate; a second pipe for allowing the organic solvent or the mixed liquid to flow; a merging portion for merging the mixed liquid having a solvent concentration less than a predetermined concentration reference value flowing through the first pipe with the liquid having a solvent concentration greater than the concentration reference value flowing through the second pipe to generate a merged mixed liquid having a solvent concentration greater than the concentration reference value; and A first dehydrator includes a first membrane separator, the first membrane separator including a first separation membrane having a lower limit of a solvent concentration applicable range equal to the concentration reference value, and separating water from the merged mixed liquid from the merged portion to increase the solvent concentration of the merged mixed liquid.

2. The organic solvent recovery device according to claim 1, further comprising a third pipe through which the mixed liquid discharged from the second processing unit for processing the substrate flows. The liquid is a new liquid of an organic solvent that has not been used for processing the substrate, The merging portion includes a regulator that adjusts a merging ratio of the mixed liquid passing through the first pipe, the mixed liquid passing through the third pipe, and the new liquid passing through the second pipe.

3. The organic solvent recovery device according to claim 2, wherein: The confluence portion includes: The first and second combining tanks; a recovery destination switching unit that switches the recovery destination of the mixed liquid passing through the first pipe and the third pipe between the first merging tank and the second merging tank; a new liquid switching unit that switches a supply destination of the new liquid between the first merging tank and the second merging tank; and A supply source switching unit switches a supply source for supplying the mixed liquid to the first dehydrator between the first merging tank and the second merging tank.

4. The organic solvent recovery device according to claim 1, comprising: Low concentration tank and high concentration tank; a first recovery destination switching unit for switching between a first low-concentration state in which the first processing unit communicates with the low-concentration tank and a first high-concentration state in which the first processing unit communicates with the high-concentration tank; and a control unit that causes the first recovery destination switching unit to select the first low-concentration state when the solvent concentration of the mixed liquid from the first processing unit is less than the concentration reference value, and causes the first recovery destination switching unit to select the first high-concentration state when the solvent concentration of the mixed liquid from the first processing unit is greater than the concentration reference value, The first pipe connects the low-concentration tank to the confluence portion, and the second pipe connects the high-concentration tank to the confluence portion. The merging portion includes a regulator that adjusts a merging ratio between the mixed liquid passing through the first pipe and the mixed liquid passing through the second pipe.

5. The organic solvent recovery device according to claim 4, further comprising a new liquid pipe for allowing a new liquid of the organic solvent that has not been used for processing the substrate to flow. The merging portion mixes the mixed liquid from the low-concentration tank via the first pipe, the mixed liquid from the high-concentration tank via the second pipe, and the new liquid via the new liquid pipe. The regulator adjusts a confluence ratio of the mixed liquid passing through the first pipe, the mixed liquid passing through the second pipe, and the new liquid passing through the new liquid pipe.

6. The organic solvent recovery device according to claim 4, further comprising a second recovery destination switching unit configured to switch between a second low-concentration state in which a second processing unit for processing a substrate is connected to the low-concentration tank and a second high-concentration state in which the second processing unit is connected to the high-concentration tank. The control unit causes the second recovery destination switching unit to select the second low concentration state when the solvent concentration of the mixed liquid from the second processing unit is a value less than the concentration reference value, and causes the second recovery destination switching unit to select the second high concentration state when the solvent concentration of the mixed liquid from the second processing unit is a value greater than the concentration reference value.

7. The organic solvent recovery device according to claim 4, comprising a storage unit storing process information indicating the processing content of the substrate by the first processing unit. The control unit calculates a solvent concentration of the mixed liquid discharged from the first processing unit based on the process information.

8. The organic solvent recovery device according to claim 7, wherein: The first processing unit includes: a substrate holding portion that holds the substrate and rotates the substrate; a spraying portion for sequentially spraying pure water and an organic solvent onto the main surface of the substrate held by the substrate holding portion; and The cup has a cylindrical shape surrounding the substrate holding portion and blocks the liquid scattered from the periphery of the substrate. The upstream end of the first pipe is connected to the cup body. The process information sets the pure water flow rate and spraying time of the pure water sprayed onto the substrate, the solvent flow rate and spraying time of the organic solvent sprayed onto the substrate, and the rotation speed of the substrate. The storage unit stores correspondence information indicating a correspondence between the rotation speed and the amount of pure water on the main surface of the substrate, that is, the amount of pure water film. The control unit calculates the pure water film amount based on the rotation speed of the substrate determined based on the process information and the corresponding relationship information, and calculates the solvent concentration of the mixed liquid discharged from the first processing unit based on the pure water film amount, the time integral value of the pure water flow rate, and the time integral value of the solvent flow rate.

9. The organic solvent recovery device according to claim 4, comprising a concentration sensor for measuring the solvent concentration of the mixed liquid. The control unit controls the first recovery destination switching unit based on the solvent concentration of the mixed liquid measured by the concentration sensor.

10. The organic solvent recovery device according to any one of claims 1 to 4, wherein: The confluence portion comprises: a tank into which the mixed liquid flows through the first pipe and the second pipe; and A stirring portion stirs the mixed liquid stored in the tank.

11. The organic solvent recovery device according to claim 10, wherein: The stirring portion includes a bubbler tube that ejects bubbles into the mixed liquid stored in the tank.

12. The organic solvent recovery device according to claim 10, wherein: The stirring unit includes a stirring circulation pipe connected to the tank, and circulates the mixed liquid through the tank and the stirring circulation pipe.

13. The organic solvent recovery device according to any one of claims 1 to 4, further comprising a second dehydrator, wherein the second dehydrator separates water from the mixed liquid flowing through one of the first pipe and the second pipe to increase the solvent concentration of the mixed liquid. The merging portion merges the mixed liquid passing through the other of the first pipe and the second pipe with the mixed liquid from the second dehydrator.

14. The organic solvent recovery device according to claim 13, wherein: The second dehydrator includes at least one of a distillation tower and an ultrasonic atomizing separator.

15. The organic solvent recovery device according to claim 13, wherein: The second dehydrator includes a second membrane separator, the second membrane separator includes a second separation membrane, and separates water from the mixed liquid to increase the solvent concentration of the mixed liquid. The concentration lower limit value of the second separation membrane is different from the concentration lower limit value of the first separation membrane.

16. The organic solvent recovery device according to claim 15, further comprising a third dehydrator provided at a stage upstream of the second dehydrator. The third dehydrator separates water from the mixed liquid flowing through one of the first pipe and the second pipe, increases the solvent concentration of the mixed liquid to be equal to or higher than the lower limit of the concentration of the second separation membrane, and supplies the mixed liquid to the second dehydrator.

17. The organic solvent recovery device according to claim 15, wherein: The second dehydrator comprises: a concentration tank storing the mixed liquid from the first pipe or the second pipe; The second circulation pipe is connected to the concentration tank and is provided with the second membrane separator. a third circulation pipe connected to the concentration tank and provided with a third membrane separator; a circulation switching unit for switching between a second circulation state in which the mixed liquid circulates through the concentrating tank and the second circulation pipe and a third circulation state in which the mixed liquid circulates through the concentrating tank and the third circulation pipe; and Control Department, The third membrane separator comprises a third separation membrane, The concentration lower limit value of the third separation membrane is lower than the concentration lower limit value of the second separation membrane, The separation constant of the second separation membrane is higher than the separation constant of the third separation membrane. The control unit causes the circulation switching unit to select the third circulation state when the solvent concentration of the mixed liquid in the concentration tank is less than the concentration lower limit value of the second separation membrane and greater than the concentration lower limit value of the third separation membrane, and causes the circulation switching unit to select the second circulation state when the solvent concentration of the mixed liquid in the concentration tank is greater than the concentration lower limit value of the second separation membrane.

18. A substrate processing system comprising: The organic solvent recovery device according to any one of claims 2, 3 and 6; a first substrate processing apparatus comprising a first load port, a plurality of the first processing units, and a first transfer unit for transferring substrates between the first load port and the plurality of the first processing units; and The second substrate processing apparatus includes a second load port, a plurality of the second processing units, and a second transfer unit that transfers substrates between the second load port and the plurality of the second processing units.

19. A method for recovering an organic solvent, comprising: a merging step of merging a mixed liquid containing an organic solvent and water discharged from a first processing unit for processing a substrate with an organic solvent or the mixed liquid to generate the mixed liquid having a concentration greater than a reference value; and The dehydration step separates water from the mixed liquid generated in the merging step using a first membrane separator including a first separation membrane having a lower limit of an applicable range of solvent concentration equal to the concentration reference value, thereby increasing the solvent concentration of the mixed liquid.

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