Organic solvent recovery apparatus, substrate processing apparatus, and organic solvent recovery method

Abstract

The invention relates to an organic solvent recovery apparatus, a substrate processing apparatus, and an organic solvent recovery method. Provided is a technique capable of separating water from a liquid mixture with high reliability and high efficiency. This organic solvent recovery device is provided with a recovery pipe (51), a first dehydrator (60), and a second dehydrator (70). A mixed solution of water and an organic solvent discharged from a processing unit (4) for processing a substrate (W) flows through the recovery pipe (51). The first dehydrator (60) includes a first membrane separator (62) that includes a first separation membrane (62c) having an application range of solvent concentration, separates water from a mixed solution having a solvent concentration that is a lower limit value of the application range, that is, a concentration lower limit value or higher, and increases the solvent concentration of the mixed solution. The second dehydrator (70) is provided at a front stage of the first dehydrator (60), separates water from the mixed liquid discharged through the recovery pipe (51), raises the solvent concentration of the mixed liquid to a concentration lower limit value or more, and supplies the mixed liquid having a solvent concentration equal to or more than the concentration lower limit value to the first dehydrator (60).

Description

Technical Field

[0001] The invention relates to an organic solvent recovery device, a substrate processing device 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 for processing substrates. The IPA recovery system includes a storage tank, a circulation piping, a pump, a dehydration unit, and a filter. The 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 returns 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 IPA 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 a filter and a 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 allows clean aqueous IPA with a high IPA concentration to be stored in the storage tank. The aqueous IPA in this storage tank is then resupplied to the processing unit, thereby reducing the amount of IPA waste.

[0004] [Background Art Literature]

[0005] [Patent Document]

[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 to separate water from the mixed liquid, a membrane separator containing a separation membrane can be considered. A separation membrane allows water to pass through while largely intercepting the organic solvent. Compared to separation methods such as distillation, this type of membrane separator can separate water from the mixed liquid with higher energy efficiency. On the other hand, if the organic solvent concentration in the mixed liquid is low, allowing the mixed liquid to flow into the membrane separator risks malfunctioning.

[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] [Technical means to solve the problem]

[0011] The first form is an organic solvent recovery device, comprising: a recovery piping, through which a mixed liquid of an organic solvent and water discharged from a processing unit for processing a substrate flows; a first dehydrator, comprising a first membrane separator, the first membrane separator comprising a first separation membrane having an applicable range of solvent concentration, the first membrane separator separating water from the mixed liquid having a solvent concentration above the lower limit of the applicable range, i.e., a concentration lower limit, thereby increasing the solvent concentration of the mixed liquid; and a second dehydrator, arranged at a position closer to the front end of the first dehydrator, separating water from the mixed liquid discharged through the recovery piping, thereby increasing the solvent concentration of the mixed liquid to above the concentration lower limit, and supplying the mixed liquid having a solvent concentration above the concentration lower limit to the first dehydrator.

[0012] The second form is an organic solvent recovery device according to the first form, wherein the second dehydrator includes a first liquid supply pipe for supplying the mixed liquid to flow toward the first dehydrator, the first dehydrator includes a second liquid supply pipe for supplying the mixed liquid to flow toward a supply tank for supplying to the treatment unit, and the first membrane separator is connected to the downstream end of the first liquid supply pipe and the upstream end of the second liquid supply pipe.

[0013] The third aspect is the organic solvent recovery device according to the first aspect, wherein the first dehydrator includes: a concentration tank storing the mixed liquid; a first circulation pipe connected to the concentration tank and provided with the first membrane separator; and a liquid feeding section provided in the first circulation pipe.

[0014] A fourth aspect is the organic solvent recovery device according to any one of the first to third aspects, wherein the second dehydrator includes at least one of a distillation tower and an ultrasonic atomizing separator.

[0015] The fifth form is an organic solvent recovery device according to any one of the first to fourth forms, wherein the second dehydrator includes a second membrane separator having a second separation membrane, and the lower limit of the applicable range of solvent concentration of the second separation membrane is less than the lower limit of the concentration of the first separation membrane, and the separation constant of the first separation membrane is greater than the separation constant of the second separation membrane.

[0016] The sixth aspect is an organic solvent recovery device according to the fifth aspect, wherein the second dehydrator includes: a concentration tank storing the mixed liquid flowing in from the recovery pipe; a second circulation pipe connected to the concentration tank and provided with the second membrane separator; and a liquid feeding section provided in the second circulation pipe.

[0017] The seventh form is an organic solvent recovery device according to the sixth form, and is further provided with a switching valve portion, and the first dehydrator includes a first circulation piping connected to the concentration tank, the first circulation piping includes: a common circulation piping, which is provided with the liquid supply portion; and a first individual piping, which is provided with the first membrane separator; the second circulation piping includes: the common circulation piping; and a second individual piping, which is provided with the second membrane separator; the switching valve portion switches between the first circulation state and the second circulation state, the first circulation state refers to the state in which the mixed liquid circulates through the concentration tank and the first circulation piping, and the second circulation state refers to the state in which the mixed liquid circulates through the concentration tank and the second circulation piping.

[0018] The eighth form is an organic solvent recovery device according to the seventh form, comprising a control unit which allows the switching valve unit to select the second circulation state when the solvent concentration of the mixed liquid is a second value less than the lower concentration limit of the first separation membrane, and allows the switching valve unit to select the first circulation state when the solvent concentration of the mixed liquid is a first value greater than the lower concentration limit.

[0019] The 9th form is an organic solvent recovery device according to any one of the 1st to 6th forms, and further comprises: a recovery point switching unit, switching between a second dehydration state and a first dehydration state, the second dehydration state refers to a state in which the mixed liquid discharged from the treatment unit is supplied to the second dehydrator, and the first dehydration state refers to a state in which the mixed liquid discharged from the treatment unit bypasses the second dehydrator and is supplied to the first dehydrator; and a control unit, which allows the recovery point switching unit to select the second dehydration state when the solvent concentration of the mixed liquid is a second value less than the lower concentration limit value of the first separation membrane, and allows the recovery point switching unit to select the first dehydration state when the solvent concentration of the mixed liquid is a first value greater than the lower concentration limit value.

[0020] The tenth form is an organic solvent recovery device according to the ninth form, comprising a storage unit storing recipe information, wherein the recipe information indicates the processing content of the processing unit on the substrate, and the control unit calculates the solvent concentration of the mixed liquid discharged from the processing unit based on the recipe information.

[0021] The 11th form is an organic solvent recovery device according to the 10th form, wherein the processing unit includes: a substrate holding portion for holding the substrate and rotating it at the same time; 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 support cup having a cylindrical shape surrounding the substrate holding portion for receiving the liquid scattered from the periphery of the substrate; and the upstream end of the recovery pipe is connected to the support cup, and the pure water flow rate and spraying time of the pure water sprayed onto the substrate, and the organic solvent sprayed onto the substrate are set in the recipe information. The solvent flow rate and the ejection time, as well as the rotation speed of the substrate, are stored in the storage unit. Correspondence information indicating the correspondence between the rotation speed and the pure water film amount is stored. The pure water film amount is the amount of pure water on the main surface of the substrate. The control unit calculates the pure water film amount based on the rotation speed of the substrate specified according to the recipe information and the correspondence information, and calculates the solvent concentration of the mixed liquid discharged from the 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.

[0022] A twelfth aspect is the organic solvent recovery device according to the ninth aspect, further comprising a concentration sensor for measuring the solvent concentration of the mixed liquid, wherein the control unit controls the recovery location switching unit based on the solvent concentration of the mixed liquid measured by the concentration sensor.

[0023] The 13th form is an organic solvent recovery device according to any one of the 1st to 6th forms, comprising: a recovery location switching unit; and a control unit for controlling the recovery location switching unit; and the recovery piping includes: a plurality of cup-side recovery pipes connected to a plurality of the processing units; a common recovery pipe connected to the downstream ends of the plurality of cup-side recovery pipes; a first dehydration pipe connecting the downstream end of the common recovery pipe to the first dehydrator; and a second dehydration pipe connecting the downstream end of the common recovery pipe to the second dehydrator; the recovery location switching unit switches between a first dehydration state and a second dehydration state, and the first dehydration state refers to connecting the common recovery pipe through the first dehydration pipe. The control unit allows the recovery location switching unit to select the first dehydration state when the solvent concentration of the mixed liquid flowing through the common recovery pipe is a first value greater than the lower concentration limit of the first separation membrane, and allows the recovery location switching unit to select the second dehydration state when the solvent concentration of the mixed liquid flowing through the common recovery pipe is a second value less than the lower concentration limit.

[0024] A fourteenth aspect is a substrate processing apparatus comprising: the organic solvent recovery apparatus according to any one of the first to thirteenth aspects; and the processing unit.

[0025] The 15th form is an organic solvent recovery method, comprising: a first step of separating water from a mixed liquid of an organic solvent and water discharged from a processing unit for processing a substrate, thereby increasing the solvent concentration of the mixed liquid; and a second step of, after the first step, using a first membrane separator comprising a first separation membrane having an applicable range of solvent concentration to separate water from the mixed liquid, thereby increasing the solvent concentration of the mixed liquid; and in the first step, the solvent concentration of the mixed liquid is increased to the lower limit value of the applicable range of the first separation membrane, that is, above the lower limit value of the concentration.

[0026] [Effects of the Invention]

[0027] According to the first, fourteenth, and fifteenth aspects, even if the solvent concentration of the mixed liquid discharged from the treatment unit is low, the second dehydrator can raise the solvent concentration of the mixed liquid to above the lower concentration limit of the first separation membrane. Therefore, the highly efficient first membrane separator can properly separate water from the mixed liquid. Consequently, the organic solvent recovery device can increase the solvent concentration of the mixed liquid with high reliability and efficiency.

[0028] According to the second embodiment, the mixed liquid from the first liquid feeding pipe passes through the first membrane separator and is supplied to the supply tank via the second liquid feeding pipe. The first dehydrator does not circulate the mixed liquid, thus shortening the time required for the first dehydrator to operate.

[0029] According to the third aspect, the size required for the first membrane separator can be reduced.

[0030] According to the fourth embodiment, the second dehydrator has a very low concentration lower limit. Therefore, even if the solvent concentration of the mixed liquid discharged from the treatment unit is very low, the second dehydrator can increase the solvent concentration of the mixed liquid to above the concentration lower limit of the first separation membrane.

[0031] According to the fifth aspect, the second dehydrator can separate water from a mixed liquid having a solvent concentration lower than the lower concentration limit of the first separation membrane, thereby increasing the solvent concentration of the mixed liquid. Furthermore, after the second membrane separator increases the solvent concentration of the mixed liquid to above the lower concentration limit of the first separation membrane, the first membrane separator, which includes the first separation membrane having a higher separation constant, further increases the solvent concentration of the mixed liquid. Therefore, the organic solvent recovery device can increase the solvent concentration of the mixed liquid more efficiently.

[0032] According to the sixth aspect, the size required for the second membrane separator can be reduced.

[0033] According to the seventh aspect, the first circulation pipe and the second circulation pipe share the liquid feeding portion, and thus the manufacturing cost can be reduced.

[0034] According to the eighth aspect, when the solvent concentration of the mixed liquid in the concentration tank is low, the mixed liquid is circulated through the second circulation pipe. Therefore, the second membrane separator, which has a lower lower concentration limit, separates water from the mixed liquid, increasing the solvent concentration. Furthermore, after the solvent concentration increases, the mixed liquid is circulated through the first circulation pipe. Therefore, the first membrane separator, which has a higher separation constant, separates water from the mixed liquid, increasing the solvent concentration. Consequently, the organic solvent recovery device can increase the solvent concentration of the mixed liquid with high reliability and efficiency.

[0035] According to the ninth and thirteenth aspects, when the solvent concentration of the mixed liquid from the treatment unit is high, the second dehydrator is not operated. Thus, power consumption of the second dehydrator can be reduced. On the other hand, when the solvent concentration of the mixed liquid from the treatment unit is low, the second dehydrator is operated. Therefore, the second dehydrator can supply a mixed liquid having a solvent concentration that is greater than the lower limit of the first separation membrane to the first dehydrator.

[0036] According to the tenth aspect, it is unnecessary to provide a concentration sensor, and thus the manufacturing cost can be reduced.

[0037] According to the eleventh aspect, the solvent concentration can be calculated with high accuracy.

[0038] According to the twelfth aspect, the solvent concentration can be obtained with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a plan view schematically showing an example of a substrate processing apparatus.

[0040] Figure 2 is a side view schematically showing an example of a processing unit.

[0041] Figure 3 This is a diagram schematically showing an example of the organic solvent recovery unit according to the first embodiment.

[0042] Figure 4 This is a diagram schematically showing an example of a specific configuration of an organic solvent recovery unit.

[0043] Figure 5 This is a flowchart showing an example of the operation of the organic solvent recovery unit.

[0044] Figure 6 This is a diagram schematically showing an example of the second dehydrator according to the second embodiment.

[0045] Figure 7This is a diagram schematically showing an example of an organic solvent recovery unit according to the third embodiment.

[0046] Figure 8 This is a diagram schematically showing a first example of a more specific configuration of the organic solvent recovery unit according to the third embodiment.

[0047] Figure 9 This is a diagram schematically showing a second example of a more specific configuration of the organic solvent recovery unit according to the third embodiment.

[0048] Figure 10 It is a diagram schematically showing a first example of a substrate processing apparatus according to a fourth embodiment.

[0049] Figure 11 This is a flowchart showing an example of the operation of the organic solvent recovery unit according to the fourth embodiment.

[0050] Figure 12 This is a diagram schematically showing an example of a processing unit according to the fourth embodiment.

[0051] Figure 13 (a) to (f) in Table 1 are diagrams schematically showing an example of the status of the processing unit in each step of Table 1.

[0052] Figure 14 This is a graph showing an example of the distance from the center of the substrate at each position on the substrate and the thickness of the pure water liquid film at each position.

[0053] Figure 15 (a) to (e) in Table 2 are diagrams schematically showing an example of the status of the processing unit in each step of Table 2.

[0054] Figure 16 This is a graph showing an example of the distance from the center of the substrate at each position on the substrate and the thickness of the liquid film at each position.

[0055] Figure 17 This is a flowchart showing an example of the operation of the concentration estimating unit.

[0056] Figure 18 It is a diagram schematically showing a second example of the substrate processing apparatus according to the fourth embodiment.

[0057] Figure 19 This is a diagram schematically showing an example of a substrate processing apparatus according to a fifth embodiment. DETAILED DESCRIPTION

[0058] The following describes the embodiments in detail with reference to the accompanying drawings. For ease of understanding, the dimensions and numbers of various components in the drawings are exaggerated or simplified as necessary. Components with identical configurations and functions are designated with the same reference numerals, and duplicate descriptions are omitted in the following description.

[0059] In the following description, the same components are denoted by the same reference numerals and their names and functions are the same, and detailed description thereof may be omitted to avoid redundancy.

[0060] In the following description, even if ordinal numbers such as "first" or "second" are used, these terms are used as appropriate to facilitate understanding of the contents of the embodiments, and the order is not limited to the order generated by these ordinal numbers.

[0061] When using expressions that express relative or absolute positional relationships (e.g., "in a direction," "along a direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.), unless otherwise specified, the expression not only expresses the strict meaning of the positional relationship, but also expresses a state formed by relative displacement of angles or distances within a tolerance or a range that can achieve equivalent functions. When using expressions that express an equal state (e.g., "same," "equal," "homogeneous," etc.), unless otherwise specified, the expression not only expresses a state of strict quantitative equality, but also expresses a state of difference with a tolerance or a range that can achieve equivalent functions. When using expressions that express shape (e.g., "quadrilateral" or "cylindrical shape," etc.), unless otherwise specified, the expression not only expresses the strict geometric meaning of the shape, but also expresses a shape with concave-convex or chamfered corners within a range that can achieve equivalent effects. When using expressions such as "equipped," "equipped," "including," or "having" a component, the expression is not an exclusive expression that excludes the presence of other components. When an expression such as “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.

[0062] <First embodiment>

[0063] <1. Substrate Processing Apparatus>

[0064] Reference Figure 1 , a substrate processing apparatus 100 according to an embodiment will be described. Figure 1 1 is a plan view schematically showing an example of the substrate processing apparatus 100 .

[0065] The substrate processing apparatus 100 is a so-called single-wafer processing apparatus that processes substrates W one by one. The substrates W processed by the substrate processing apparatus 100 are, for example, semiconductor substrates. The substrates W are, for example, disk-shaped.

[0066] The substrate processing apparatus 100 includes a load port 1 , a transfer robot 2 , a main transport robot 3 , a processing unit 4 , an organic solvent recovery unit 5 , and a control unit 6 .

[0067] The loading port 1 is an interface for placing or removing a substrate W from 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 illustrated example). The plurality of loading ports 1 are arranged in a row in the horizontal direction, for example. The carrier C can be a type that stores the substrate W in a confined space (for example, a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface) wafer box, etc.), or a type that exposes the substrate W to external gas (for example, an OC (Open Cassette) etc.).

[0068] The transfer robot 2 is a transport device that transports the substrate W. As an example, the transfer 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 transfer robot 2 includes a drive mechanism (not shown) for turning each hand 21 and bending, extending, turning, and raising and lowering each arm 22. The transfer robot 2 transports the substrate W between the carrier C placed on the loading port 1 and the main transport robot 3. That is, the transfer robot 2 approaches or moves away from the carrier C placed on the loading port 1, and performs a carry-out action (i.e., an action of taking out the substrate W contained in the carrier C by the hand 21) and a carry-in action (i.e., an action of placing the substrate W held by the hand 21 into the carrier C). In addition, the transfer robot 2 approaches or moves away from the handover position to transfer the substrate W to and from the main transport robot 3.

[0069] The main transfer robot 3 is a transfer device for transferring the substrate W. As an example, the main transfer robot 3 is a horizontal multi-joint robot, which includes a pair of hands 31, 31 for holding the substrate W, and an arm 32 connected to each hand 31. In addition, the main transfer robot 3 includes a drive mechanism (not shown) for turning each hand 31, and for flexing, extending, turning, and lifting each arm 32. The main transfer robot 3 transfers the substrate W between the transfer robot 2 and each processing unit 4. That is, the main transfer robot 3 approaches or moves away from the handover position, and transfers the substrate W with the transfer robot 2. In addition, the main transfer robot 3 approaches or moves away from the processing unit 4, and performs 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 by the hand 31).

[0070] 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 illustrated example) towers are provided to surround the main transfer robot 3. The specific structure of the processing unit 4 will be described below.

[0071] The organic solvent recovery unit 5 recovers the organic solvent from the treatment unit 4 and supplies it back to the treatment unit 4 after purification. As an example, an organic solvent recovery unit 5 can be provided in a one-to-one correspondence with each of the multiple towers, with each organic solvent recovery unit 5 recovering and supplying the organic solvent to each treatment unit 4 included in the corresponding tower. The specific structure of the organic solvent recovery unit 5 will be described below.

[0072] The control unit 6 controls the operation of each component of the substrate processing apparatus 100 (the load port 1, the transfer robot 2, the main transport robot 3, the processing unit 4, and the organic solvent recovery unit 5). The control unit 6 is composed of, for example, a conventional computer having electrical circuits. As an example, the control unit 6 includes a CPU (Central Processor Unit) as a central processing unit that performs various calculations (data processing), a ROM (Read Only Memory) that stores basic programs, etc., a RAM (Random Access Memory) used as a work area when the CPU performs specified processing (data processing), a storage device composed of a non-volatile storage device such as a flash memory or a hard disk drive, and a bus that interconnects these components. A program that specifies the processing performed by the control unit 6 may also be stored in the storage device or RAM. In this case, for example, the CPU can execute the program, causing each component of the substrate processing apparatus 100 to be controlled by the control unit 6, and the processing specified by the program to be performed in the substrate processing apparatus 100. That is, the CPU can execute a program, and the circuit that performs the processing specified by the program can be realized in the control unit 6. Of course, part or all of the control performed by the control unit 6 (part or all of the circuit implemented by the control unit 6) can also be executed (implemented) by hardware such as a dedicated logic circuit.

[0073] <2. Processing Unit>

[0074] Reference Figure 2 , processing unit 4 is described. Figure 2 1 is a side view schematically showing an example of the processing unit 4 .

[0075] <2-1. Configuration of Processing Unit>

[0076] 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 (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.

[0077] The spin chuck 41 holds the substrate W in a horizontal position (with the thickness of the substrate W extending in the vertical direction (vertical direction)) and rotates the substrate W about an axis (rotation axis) A extending vertically through the center of its main surface. Specifically, the spin chuck 41 includes, for example, a spin base 411. The spin base 411 is a disk-shaped component, disposed with its thickness extending in the vertical direction. A plurality of chuck pins 412 are provided on the top surface of the spin base 411. The chuck pins 412 are arranged at equal intervals along a circumference corresponding to the periphery of the substrate W. A link mechanism (not shown) is connected to the chuck pins 412, which moves them between an abutment position and a release position. The "abutment position" refers to the position where the chuck pins 412 abut the periphery of the substrate W. The "release position" refers to the position where the chuck pins 412 are clear of the periphery of the substrate W. When the chuck pins 412 are in the abutment position, the substrate W is held (clamped) in a horizontal position above the spin base 411. When the chuck pins 412 are each positioned in the release position, the substrate W is released from its grip. The link mechanism switches the position of the chuck pins 412 in accordance with instructions from the control unit 6. Specifically, the control unit 6 controls the timing of holding and releasing the substrate W. Furthermore, the rotation base 411 is connected to a rotation motor 414 via a shaft 413 coaxial with the rotation axis A. The shaft 413 and the rotation motor 414 are housed in a protective cover 415. The rotation motor 414 rotates the shaft 413 about the rotation axis A. This causes the rotation base 411, and thus the substrate W held thereon, to rotate about the rotation axis A. The rotation motor 414 rotates the rotation base 411 in accordance with instructions from the control unit 6. Specifically, the rotation speed, rotation start timing, and rotation end timing of the rotation base 411 (and thus the substrate W) are controlled by the control unit 6.

[0078] The cup 42 has a cylindrical shape surrounding the spin chuck 41 and receives processing liquid discharged from the substrate W held and rotated by the spin chuck 41. Specifically, the cup 42 includes, for example, a cylindrical guide portion 421 coaxially arranged with the rotation axis A; an inclined portion 422 connected to the upper end of the guide portion 421, which tapers upward; and a liquid receiving portion 423 connected to the lower end of the guide portion 421, 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 chemical solution (not shown) and a cup-side recovery pipe 424 for IPA) for recovering the liquid received therein. Furthermore, a cup-side lifting mechanism 425 is connected to the cup 42 to raise and lower it between a lower position and an upper position. The "lower position" refers to a position in which the upper end of the cup 42 (specifically, the upper end of the inclined portion 422) is positioned below the substrate W held by the spin chuck 41. The "upper position" means that the upper end of the retainer 42 is positioned above the substrate W held by the spin chuck 41. The retainer elevating mechanism 425 elevates the retainer 42 in accordance with instructions from the control unit 6. In other words, the position of the retainer 42 is controlled by the control unit 6.

[0079] The discharge unit 430 (specifically, the nozzle 43) discharges the processing liquid onto the upper surface of the substrate W held by the spin chuck 41. Here, for example, the nozzles 43 are provided according to the type of processing liquid. Specifically, a nozzle 43 is provided for discharging a chemical liquid (hereinafter referred to as a "chemical liquid nozzle 43a"), a nozzle 43 for discharging a rinse liquid (hereinafter referred to as a "rinsing liquid nozzle 43b"), and a nozzle 43 for discharging IPA (hereinafter referred to as an "IPA nozzle 43c").

[0080] The chemical nozzle 43a sprays a chemical liquid onto the upper surface of the substrate W held by the spin chuck 41. The chemical nozzle 43a is connected to a chemical liquid supply source 433a via a chemical liquid pipe 432a through which a chemical liquid valve 431a is inserted. After the chemical liquid valve 431a is opened, the chemical liquid is supplied to the chemical liquid nozzle 43a through the chemical liquid pipe 432a, and then the chemical liquid is sprayed from the chemical liquid nozzle 43a. The chemical liquid valve 431a is opened or closed according to instructions from the control unit 6. In other words, the timing of spraying 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 may 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, an organic acid (for example, citric acid, oxalic acid, etc.), an organic base (for example, TMAH: tetramethylammonium hydroxide, etc.), a surfactant, and a preservative.

[0081] The rinse liquid nozzle 43b discharges rinse liquid onto 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 through which a rinse liquid valve 431b is inserted. When the rinse liquid valve 431b is opened, rinse liquid is supplied to the rinse liquid nozzle 43b via the rinse liquid pipe 432b, and then the rinse liquid is discharged from the rinse liquid nozzle 43b. The rinse liquid valve 431b opens or closes according to instructions from the control unit 6. In other words, the timing of the discharge of 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, electrolytic ionized water, hydrogen water, ozone water, and hydrochloric acid water with a diluted concentration (e.g., approximately 10 to 100 ppm).

[0082] The IPA nozzle 43c discharges IPA (i.e., a liquid primarily composed of IPA) onto the upper surface of the substrate W held by the spin chuck 41. The IPA nozzle 43c is connected to the organic solvent recovery unit 5 via an IPA pipe 432c, through which an IPA valve 431c is inserted. When the IPA valve 431c is opened, IPA is supplied to the IPA nozzle 43c via the IPA pipe 432c, and then discharged from the IPA nozzle 43c. The IPA valve 431c opens or closes in accordance with instructions from the control unit 6. In other words, the timing of IPA discharge from the IPA nozzle 43c is controlled by the control unit 6.

[0083] Furthermore, a nozzle movement mechanism may be connected to at least one of the chemical liquid nozzle 43a, the rinse liquid nozzle 43b, and the IPA nozzle 43c to move the nozzle between a processing position and a retreat position. The "processing position" refers to the position at which 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" refers to the position at which the nozzles 43a, 43b, and 43c are located outside (radially outward) of the periphery of the substrate W held on the spin chuck 41, as viewed from above. In this case, the nozzle movement mechanism moves the nozzles 43a, 43b, and 43c in accordance with 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.

[0084] <2-2. Operation of Processing Unit>

[0085] An example of the operation of the processing unit 4 will be described. The operations performed by the processing unit 4 are 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 lifting mechanism 425, the chemical valve 431a, the rinse liquid valve 431b, the IPA valve 431c, etc.).

[0086] After the main transfer robot 3 carries the substrate W into the processing chamber 44 , the spin chuck 41 holds the substrate W. Then, the spin chuck 41 starts to rotate.

[0087] In this state, the chemical liquid valve 431a is opened. In this way, the chemical liquid is sprayed from the chemical liquid nozzle 43a toward the upper surface of the substrate W held and rotated by the spin chuck 41. As a result, the chemical liquid is supplied to the entire upper surface of the substrate W, and the substrate W is treated with the chemical liquid (chemical liquid treatment step). For example, when hydrofluoric acid is used as the chemical liquid, foreign matter such as particles must be removed from the substrate W. During the chemical liquid treatment step, the cup 42 is arranged in the upper position. Therefore, the chemical liquid scattered around the substrate W is caught by the cup 42. That is, the chemical liquid scattered around the substrate W is caught by the inclined portion 422, guided downward by the guide portion 421, and gathered in the liquid receiving portion 423. The chemical liquid caught by the cup 42 (that is, the chemical liquid gathered in the liquid receiving portion 423) is recovered through the cup-side recovery pipe (not shown) for the chemical liquid.

[0088] At a time point after a specified time has passed since the start of spraying the chemical liquid, the chemical liquid valve 431a is closed. In this way, the chemical liquid stops being sprayed from the chemical liquid nozzle 43a. Then, the rinsing liquid valve 431b is opened. In this way, the rinsing liquid is sprayed from the rinsing liquid nozzle 43b toward the upper surface of the substrate W that is held and rotated by the rotary chuck 41. As a result, the rinsing liquid is supplied to the entire upper surface of the substrate W, and the chemical liquid attached to the substrate W is washed away by the rinsing liquid (rinsing treatment step). During the rinsing treatment step, the support cup 42 is also arranged in the upper position. Therefore, the chemical liquid and rinsing liquid scattered around the substrate W are caught by the support cup 42. The chemical liquid and rinsing liquid caught by the support cup 42 are recovered through the support cup side recovery pipe (not shown) for the chemical liquid.

[0089] At a time point after a specified time has passed since the start of spraying of the rinsing liquid, the rinsing liquid valve 431b is closed. In this way, the rinsing liquid stops being sprayed from the rinsing liquid nozzle 43b. Then, the IPA valve 431c is opened. In this way, IPA is sprayed from the IPA nozzle 43c toward the upper surface of the substrate W that is held and rotated by the rotary chuck 41. Thus, IPA is supplied to the entire upper surface of the substrate W, and the rinsing liquid attached to the substrate W is replaced with IPA (IPA supply step). During the IPA supply step, the support cup 42 is also arranged in the upper position. Therefore, the rinsing liquid and IPA scattered around the substrate W are caught by the support cup 42. The rinsing liquid and IPA caught by the support cup 42 are recovered through the support cup side recovery pipe 424 for IPA.

[0090] At a point in time after a specified time has passed since the start of IPA supply, the IPA valve 431c is closed. In this way, IPA stops being ejected from the IPA nozzle 43c. At this stage, the rinsing liquid on the substrate W has been completely replaced by IPA, forming a liquid film of IPA covering the entire upper surface of the substrate W. Then, the rotary 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 periphery of the substrate W by centrifugal force (spin drying step). During the period when the substrate W rotates at high speed, the support cup 42 is also arranged in the upper position. Therefore, the IPA scattered to the periphery of the substrate W is caught by the support cup 42. The IPA caught by the support cup 42 is recovered through the support cup side recovery pipe 424 for IPA.

[0091] After a predetermined time has passed since the spin chuck 41 started rotating at high speed, the spin chuck 41 stops rotating. At this stage, the IPA has been 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 .

[0092] This completes a series of processes for one substrate W. In the processing unit 4 , the series of operations are repeatedly performed, whereby a plurality of substrates W are processed one by one in sequence.

[0093] <3. Overview of Organic Solvent Recovery Unit 5 (Organic Solvent Recovery Device)>

[0094] Reference Figure 3 , the structure of the organic solvent recovery unit 5 will be described. Figure 3 1 is a diagram schematically showing an example of the organic solvent recovery unit 5 according to the first embodiment. Hereinafter, the outline of the organic solvent recovery unit 5 will be described first, and then the components of the organic solvent recovery unit 5 will be described in detail.

[0095] The organic solvent recovery section 5 includes a first dehydrator 60 and a second dehydrator 70. The second dehydrator 70 is arranged at a position closer to the front section than the first dehydrator 60. The downstream end of the recovery pipe 51 is connected to the second dehydrator 70. In addition, the downstream end of each cup-side recovery pipe 424 is connected to the recovery pipe 51. The mixed liquid of the organic solvent and water discharged from the treatment unit 4 flows to the recovery pipe 51. The organic solvent is, for example, an organic solvent with a higher volatility than water, or an organic solvent with a lower surface tension than water. As a specific example, it is IPA (isopropyl alcohol). The mixed liquid is supplied (recovered) to the second dehydrator 70 through the recovery pipe 51. In addition, a buffer tank can also be provided between the second dehydrator 70 and the treatment unit 4. That is, the mixed liquid discharged from the treatment unit 4 can also be temporarily stored in the buffer tank, and then the mixed liquid can be supplied from the buffer tank to the second dehydrator 70 through the recovery pipe 51.

[0096] Here, it is assumed that the concentration of the organic solvent in the mixed liquid discharged from the treatment unit 4 (hereinafter referred to as the solvent concentration) is low. As an example, the solvent concentration of the mixed liquid discharged from the treatment unit 4 is 30 wt % or less.

[0097] The second dehydrator 70 separates water from the mixed liquid, increasing the solvent concentration of the mixed liquid. An example of the specific structure of the second dehydrator 70 will be described in detail below. The second dehydrator 70 supplies the mixed liquid with increased solvent concentration to the first dehydrator 60 via a first liquid supply pipe 78. The upstream end of the first liquid supply pipe 78 is connected to the second dehydrator 70, and the downstream end of the first liquid supply pipe 78 is connected to the first dehydrator 60.

[0098] The first dehydrator 60 includes a first membrane separator 62. The mixed liquid from the second dehydrator 70 flows into the first membrane separator 62. The first membrane separator 62 separates water from the mixed liquid, thereby further increasing the solvent concentration of the mixed liquid.

[0099] like Figure 3 As shown, the first membrane separator 62 includes a first mixing path 62a, a first water path 62b, and a first separation membrane 62c. A mixed liquid flows into the first mixing path 62a. The first separation membrane 62c separates the first mixing path 62a from the first water path 62b. The first separation membrane 62c is a membrane that allows water in the mixed liquid to pass through while largely intercepting the organic solvent. A portion of the water in the mixed liquid flowing 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 mixed liquid passing through the first mixing path 62a becomes higher than the solvent concentration of the mixed liquid before entering the first mixing path 62a. The first dehydrator 60 uses the first membrane separator 62 to increase the solvent concentration of the mixed liquid to above a specified reuse reference value. The reuse reference value refers to the solvent concentration that can be used in the treatment unit 4 and is, for example, set in advance. Hereinafter, the mixed liquid whose solvent concentration has been increased to above the reuse reference value is referred to as reused liquid. It can also be said that the first dehydrator 60 separates water from the mixed liquid from the second dehydrator 70 to produce a reused liquid.

[0100] The upstream end of the second liquid supply pipe 85 is connected to the first dehydrator 60, and the downstream end of the second liquid supply pipe 85 is connected to the supply tank Tk3 for supplying to the processing unit 4. The first dehydrator 60 supplies the reused liquid to the supply tank Tk3 via the second liquid supply pipe 85. The mixed liquid in the supply tank Tk3 is then supplied to the processing unit 4 again.

[0101] In addition, the first separation membrane 62c has an applicable range of solvent concentration. That is, the first separation membrane 62c can properly separate water from a mixed liquid having a solvent concentration within the applicable range. On the other hand, if a mixed liquid having a solvent concentration less than the lower limit of the applicable range flows into the first membrane separator 62, then the first separation membrane 62c may malfunction. For example, the first membrane separator 62 may not be able to fully separate water from the mixed liquid. Alternatively, if the ratio of water molecules passing through the first separation membrane 62c exceeds the allowable value, the crystal structure constituting the first separation membrane 62c will partially dissolve, resulting in a significant shortening of the service life of the first separation membrane 62c. Hereinafter, the lower limit of the applicable range of solvent concentration will be 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%.

[0102] In the first embodiment, the solvent concentration of the mixed liquid discharged from the treatment unit 4 is less than the lower concentration limit of the first separation membrane 62c. This mixed liquid is supplied to the second dehydrator 70, which is located upstream of the first dehydrator 60. The lower concentration limit of the second dehydrator 70 is less than the solvent concentration of the mixed liquid discharged from the treatment unit 4. Therefore, the second dehydrator 70 can properly separate water from the mixed liquid discharged from the treatment unit 4, thereby increasing the solvent concentration of the mixed liquid. The second dehydrator 70 increases the solvent concentration of the mixed liquid to above the lower concentration limit of the first separation membrane 62c. The second dehydrator 70 then supplies the separated mixed liquid to the first dehydrator 60.

[0103] Since the solvent concentration of the mixed liquid from the second dehydrator 70 is greater than the lower limit of the concentration of the first separation membrane 62c, the first dehydrator 60 can properly separate water from the mixed liquid using the first membrane separator 62. As a result, the first dehydrator 60 can properly produce recycled liquid.

[0104] As described above, the organic solvent recovery unit 5 increases the solvent concentration of the mixed liquid discharged from the processing unit 4 to produce 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.

[0105] Furthermore, in the first embodiment, the second dehydrator 70 first increases the solvent concentration of the mixed liquid from the treatment unit 4. Therefore, even if the solvent concentration of the mixed liquid from the treatment unit 4 is below the lower limit of the applicable range of the first separation membrane 62c, the second dehydrator 70 can still increase the solvent concentration of the mixed liquid to above the lower limit of the concentration of the first separation membrane 62c. Therefore, the first membrane separator 62 of the first dehydrator 60 can appropriately increase the solvent concentration of the mixed liquid. In other words, the reliability of the organic solvent recovery unit 5 can be improved.

[0106] Furthermore, because the first dehydrator 60 uses the first membrane separator 62 to separate water from the mixed liquid, the first dehydrator 60 is highly efficient. For example, the energy efficiency of the first dehydrator 60 is higher than that of other separation methods such as distillation. Specifically, in the first embodiment, after the second dehydrator 70 raises the solvent concentration of the mixed liquid to above the lower limit of the first separation membrane 62c, the first dehydrator 60 uses the highly efficient first membrane separator 62 to further increase the solvent concentration of the mixed liquid.

[0107] Therefore, 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 device size of the first membrane separator 62 is small, the organic solvent recovery unit 5 can be realized with a smaller size.

[0108] <3-1. Specific example of the organic solvent recovery unit 5>

[0109] Figure 4 Schematically shows an example of a specific structure of the organic solvent recovery unit 5. The organic solvent recovery unit 5 can be housed in a first housing box 50a (see FIG. Figure 1 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)).

[0110] <3-1-1. Second Dehydrator>

[0111] Figure 4 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 51 is connected to the distillation column 701, and the upstream end of the steam pipe 731 is connected to, for example, the upper portion of the distillation column 701. The downstream end of the steam pipe 731 is connected to the cooler 702.

[0112] Figure 4In the example shown, a recovery valve 52 is inserted into the recovery pipe 51. When the control unit 6 opens the recovery valve 52, the mixed liquid from the treatment unit 4 is supplied to the distillation column 701 through the recovery pipe 51. The distillation column 701 includes a heating unit (not shown) for heating the mixed liquid. The distillation column 701 separates water from the mixed liquid by distillation, which exploits the difference in boiling points between 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 column 701 vaporizes the mixed liquid and supplies vapor containing a large amount of the organic solvent to the upstream end of the steam pipe 731. Although the vapor flowing into the upstream end of the steam pipe 731 may contain not only the organic solvent but also water, its solvent concentration becomes higher than that before it enters the distillation column 701. This vapor flows through the steam pipe 731 into the cooler 702. The upstream end of a discharge pipe (not shown) for discharging water may be connected to the lower portion of the distillation column 701 .

[0113] The upstream end of the liquid piping 732 is also connected to the cooler 702. The cooler 702 cools the vapor to condense it. The cooler 702 may also include a heat exchanger, for example. The vapor passes through the interior of the heat exchanger. The cooler 702 may include a heat pump type cooling source for cooling the heat exchanger, or a cooling source including a Peltier element. The vapor loses heat in the heat exchanger and becomes a liquid (i.e., a mixed liquid). The mixed liquid flows into the upstream end of the liquid piping 732. The solvent concentration of the mixed liquid is higher than the solvent concentration of the mixed liquid before it flows into the distillation column 701.

[0114] like Figure 4 As shown, the second dehydrator 70 may include a plurality of distillation towers 701 and a plurality of coolers 702 . Figure 4 In the example of FIG. 7 , a set of distillation columns 701 and a cooler 702 are connected in series. Figure 4In 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 731 connects distillation tower 701a and cooler 702a, and liquid pipe 732 connects cooler 702a and distillation tower 701b. Vapor from distillation tower 701a passes through cooler 702a and condenses to form a mixed liquid, which is then supplied to distillation tower 701b. The upstream end of steam pipe 733 is connected to, for example, the upper portion of distillation tower 701b, and the downstream end of steam pipe 733 is connected to cooler 702b. The vapor from the mixed liquid from distillation tower 701b is cooled by cooler 702b and condensed to form a mixed liquid. The cooler 702 b is connected to the upstream end of the first liquid supply pipe 78 , and the mixed liquid from the cooler 702 b is supplied to the first dehydrator 60 through the first liquid supply pipe 78 .

[0115] The second dehydrator 70 may also include a pump and a valve (not shown). For example, a liquid delivery valve may be inserted into the first liquid delivery pipe 78 , or a pump may be inserted into the liquid pipe 732 .

[0116] As mentioned above, Figure 4 In the example of , the second dehydrator 70 uses a distillation tower 701 and a cooler 702 to separate water from the mixed liquid, thereby increasing the solvent concentration of the mixed liquid. Figure 4 In this example, the second dehydrator 70 includes multiple distillation towers 701 and multiple coolers 702. Thus, each time the mixed liquid passes through a set of distillation towers 701 and coolers 702, the solvent concentration of the mixed liquid increases. Therefore, compared to a case where the second dehydrator 70 utilizes a single distillation tower 701 and a single cooler 702, the solvent concentration of the mixed liquid can be increased by a greater amount. The amount of increase in solvent concentration in the second dehydrator 70 is preset so that the solvent concentration after the increase reaches or exceeds the lower limit of the concentration of the first separation membrane 62c. The number of distillation towers 701 and coolers 702 is preset based on this increase.

[0117] <3-1-2. First Dehydrator>

[0118] Figure 4 In the example of , the first dehydrator 60 includes a concentration tank Tk1 and a first circulation unit 61 .

[0119] (a) Concentration tank Tk1

[0120] The downstream end of the first liquid supply pipe 78 is connected to the concentration tank Tk1. The mixed liquid is supplied from the second dehydrator 70 through the first liquid supply pipe 78 to the concentration tank Tk1. The concentration tank Tk1 stores the mixed liquid. As described above, the solvent concentration of the mixed liquid is at least the lower limit of the concentration of the first separation membrane 62c.

[0121] (b) First circulation unit 61

[0122] 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 concentrator tank Tk1. The first circulation pipe 63 is a pipe that returns the mixed liquid from the concentrator tank Tk1 to the concentrator tank Tk1. In other words, the first circulation pipe 63 forms a first circulation path for the mixed liquid stored in the concentrator tank Tk1 to circulate, flowing out of the concentrator tank Tk1 and returning to the concentrator tank Tk1. Figure 4 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.

[0123] 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 mixed liquid passes through the first mixing path 62a. A portion of the water in the mixed liquid flowing 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 mixed liquid after the first membrane separator 62 in the first circulation piping 63 becomes higher than the solvent concentration of the mixed liquid before the first membrane separator 62. The first circulation section 61 circulates the mixed liquid through the first circulation piping 63, so the mixed liquid continuously flows into the first membrane separator 62. Thus, the first membrane separator 62 continuously separates water from the mixed liquid. As a result, the solvent concentration of the circulating mixed liquid increases over time. Hereinafter, the liquid separated from the mixed liquid by the first membrane separator 62 is referred to as the separated liquid. The separation liquid is generally water.

[0124] 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 formed by interconnecting 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 may be used as the material for the first separation membrane 62c. A two-dimensional material is a material composed of one layer of atoms, such as molybdenum sulfide (MoS2), or a composite atomic layer compound formed by a pre-transition metal (such as titanium or vanadium) and a light element (carbon or nitrogen). Alternatively, as the material for the first separation membrane 62c, a MOF (Metal Organic Frameworks) material or a carbon material (such as graphene or graphene oxide) may also be used. Here, a zeolite membrane is used as the first separation membrane 62c.

[0125] The first water path 62b is connected to the upstream end of the separation discharge piping 66. The separated liquid is discharged to the outside (for example, to the drainage treatment unit of the factory equipment) through the separation discharge piping 66. A pressure reducing pump for reducing the pressure in the first water path 62b may also be provided in the separation discharge piping 66. Figure 4 As shown, a discharge valve 67 is inserted into the separation discharge pipe 66 .

[0126] Figure 4 In the example of , 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 .

[0127] A pump 64 is inserted into the first circulation pipe 63. For example, the pump 64 is installed upstream of the first membrane separator 62. A first switching valve 651 and a 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.

[0128] Various sensors can be inserted into the first circulation piping 63. For example, a concentration sensor Sn63 for measuring the concentration of an 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.

[0129] <3-1-3. Recyclable Liquid Supply Unit 89>

[0130] Figure 4 In the example of , 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 second liquid supply pipe 85, a liquid supply valve 86, and a pump 64 as an example of a liquid supply unit.

[0131] Figure 4 In the example shown, the supply tank Tk3 is connected to the first circulation pipe 63 via the second liquid supply pipe 85. That is, the downstream end of the second liquid supply pipe 85 is connected to the supply tank Tk3, and the upstream end of the second liquid supply pipe 85 is connected to the first circulation pipe 63. Specifically, the upstream end of the second 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 second 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. A liquid supply valve 86 is inserted into the second liquid supply pipe 85. In addition, the upstream end of the second liquid supply pipe 85 does not necessarily have to be connected to the first circulation pipe 63, but can also be connected to the concentration tank Tk1. In this case, a pump different from the pump 64 is provided in the second liquid supply pipe 85.

[0132] <New Liquid Supply>

[0133] like Figure 3 As shown, supply tank Tk3 is connected to fresh liquid supply source 403 via fresh liquid piping 401. Specifically, the downstream end of fresh liquid piping 401 is connected to supply tank Tk3, while the upstream end of fresh liquid piping 401 is connected to fresh liquid supply source 403. Fresh liquid supply source 403 is a source of unused organic solvent (e.g., IPA with a concentration of 99.8 wt% or greater) that has never been supplied to substrate W. A fresh liquid valve 402 is inserted into fresh liquid piping 401.

[0134] The supply tank Tk3 is connected to the IPA nozzle 43c via the third liquid supply pipe 404. Specifically, the supply tank Tk3 is connected to one end of the third liquid supply pipe 404, and the IPA nozzle 43c (specifically, the IPA pipe 432c connected to the IPA nozzle 43c) is connected to the other end of the third liquid supply pipe 404. For example, the third liquid supply pipe 404 is connected to the IPA nozzle 43c included in each of the multiple processing units 4 belonging to the same tower.

[0135] A pump (supply-side liquid supply pump) 405 is inserted into the third liquid supply pipe 404. A filter 407 is inserted into the third liquid supply pipe 404 downstream of the supply-side liquid supply pump 405. A temperature regulator 406 is inserted into the third liquid supply pipe 404 upstream of the filter 407 and downstream of the supply-side liquid supply pump 405.

[0136] Various sensors are inserted into the third liquid supply pipe 404. For example, a temperature sensor Sn41 is inserted into the third liquid supply pipe 404 to measure the temperature of the fluid flowing through the third liquid supply pipe 404. The temperature sensor Sn41 is inserted, for example, upstream of the filter 407 and downstream of the temperature regulator 406. The temperature regulator 406 adjusts the temperature of the reuse liquid supplied to the processing unit 4 to within a specified temperature range appropriate for processing the substrate W.

[0137] <3-2. An Example of Operation of the Organic Solvent Recovery Unit 5>

[0138] Figure 5 This is a flowchart illustrating an example of the operation of the organic solvent recovery unit 5. First, the second dehydrator 70 separates water from the mixed liquid from the treatment unit 4, thereby increasing the solvent concentration in the mixed liquid (step S1: second dehydrator step, equivalent to the first step). Specifically, the controller 6 opens the recovery valve 52, supplying the mixed liquid from the treatment unit 4 to the second dehydrator 70 via the recovery pipe 51. The controller 6 then controls the distillation column 701 and the cooler 702, causing the second dehydrator 70 to raise the solvent concentration in the mixed liquid to above the lower limit of the concentration of the first separation membrane 62c (e.g., 50 wt%). As an example, the solvent concentration of the mixed liquid after separation achieved by the second dehydrator 70 is closer to the lower limit of the concentration of the first separation membrane 62c (e.g., 50 wt%) than the reuse reference value (e.g., 99 wt%) (e.g., approximately 60%). This mixed liquid is then supplied to the first dehydrator 60 via the first liquid supply pipe 78. As an example, the mixed liquid is stored in the concentration tank Tk1.

[0139] Next, the first dehydrator 60 separates water from the mixed liquid, further increasing the solvent concentration of the mixed liquid (step S2: first dehydrator step, equivalent to the second step). Specifically, the first circulation unit 61 circulates the mixed liquid through the first circulation pipe 63. 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 mixed liquid circulates through the first circulation path including the concentration tank Tk1 and the first circulation pipe 63. Through this circulation, the 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 mixed liquid, and the separation liquid is continuously discharged to the outside through the separation discharge pipe 66. Therefore, the solvent concentration of the mixed liquid in the circulation increases over time.

[0140] The controller 6 causes the first circulation section 61 to circulate the mixed liquid until the solvent concentration of the circulating mixed liquid reaches or exceeds a specified reuse reference value. The reuse reference value may be, for example, 60 wt% or more, 70 wt% or more, 80 wt% or more, 90 wt% or more, 95 wt% or more, or 99 wt% or more. For example, the controller 6 may compare the solvent concentration measured by the concentration sensor Sn63 with the reuse reference value and stop the circulation of the first circulation section 61 when the solvent concentration reaches or exceeds the reuse reference value. 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.

[0141] Through this circulation, the mixed liquid (i.e., the reused liquid) with a high solvent concentration is stored in the concentration tank Tk1. Alternatively, the controller 6 may use the passage of a specified first dehydration time as a trigger to stop the circulation in the first circulation unit 61. The first dehydration time is, for example, pre-set to a time period longer than the time required for the solvent concentration to reach a reuse reference value or higher. For example, the first dehydration time can be set to several tens of minutes or several hours.

[0142] Next, the reused liquid supply unit 89 supplies the reused liquid to the supply tank Tk3 (step S3: supply step, third step). Specifically, the controller 6 opens the liquid supply valve 86 and activates the pump 64. This allows the reused liquid in the concentration tank Tk1 to be supplied to the supply tank Tk3 via at least the second liquid supply pipe 85.

[0143] As described above, the organic solvent recovery unit 5 increases the solvent concentration of the mixed liquid from the treatment unit 4 to prepare a reused liquid, which is then supplied to the supply tank Tk3 .

[0144] In the example described above, the second dehydrator 70 first increases the solvent concentration of the mixed liquid using a distillation tower 701 and a cooler 702 (step S1). The lower limit of the concentration of the distillation tower 701 is very low, for example, it can be substantially zero. Therefore, even if the solvent concentration of the mixed liquid discharged from the treatment unit 4 is very low, the second dehydrator 70 can appropriately increase the solvent concentration of the mixed liquid. On the other hand, the distillation tower 701 and the cooler 702 consume relatively high power, resulting in low energy efficiency. Energy efficiency here can also be defined as the ratio of the increase in solvent concentration to the amount of power consumed. Furthermore, the distillation tower 701 is larger than the first membrane separator 62. Furthermore, based on the principle of distillation, it is difficult for the second dehydrator 70 to increase the solvent concentration of the mixed liquid above the azeotropic point.

[0145] In the first embodiment, after the second dehydrator 70 raises the solvent concentration of the mixed solution to above the lower limit of the concentration of the first separation membrane 62c, the first dehydrator 60 uses the first membrane separator 62 to further increase the solvent concentration of the mixed solution (step S2). Since the energy efficiency of membrane separation is higher than the energy efficiency of distillation, the organic solvent recovery unit 5 can increase the solvent concentration of the mixed solution with higher efficiency. That is, compared with the case where only the second dehydrator 70 raises the solvent concentration of the mixed solution, the organic solvent recovery unit 5 can increase the solvent concentration of the mixed solution with higher efficiency. In addition, according to the principle of membrane separation implemented by the first membrane separator 62, the solvent concentration of the mixed solution can also be increased to above the azeotropic point. That is, the organic solvent recovery unit 5 can more simply increase the solvent concentration of the mixed solution to a value above the azeotropic point.

[0146] Furthermore, in the example described above, the first dehydrator 60 increases the solvent concentration of the mixed liquid by repeatedly flowing the mixed liquid into the first membrane separator 62 through circulation implemented by the first circulation section 61. Furthermore, the larger the size of the first membrane separator 62 (i.e., the size of the first separation membrane 62c), the greater the increase in solvent concentration achieved by the first membrane separator 62. Therefore, if the first dehydrator 60 does not circulate the mixed liquid, the size of the first membrane separator 62 must be larger to ensure a sufficient increase in solvent concentration. In contrast, in the specific example described above, the first dehydrator 60 increases the solvent concentration of the mixed liquid through circulation implemented by 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 the reuse reference value can be reduced.

[0147] <Second embodiment>

[0148] The configuration of the substrate processing apparatus 100 of the second embodiment is the same as that of the substrate processing apparatus 100 of the first embodiment. However, the second embodiment is different from the first embodiment in a specific example of a second dehydrator 70. Figure 6 This is a diagram schematically showing an example of the second dehydrator 70 according to the second embodiment. Figure 6 In the example of , the second dehydrator 70 includes an ultrasonic atomizing separator 704. The ultrasonic atomizing separator 704 is connected to the downstream end of the recovery pipe 51, the upstream end of the first liquid supply pipe 78, and the upstream end of the separation and discharge pipe 705.

[0149] The mixed liquid flows through the recovery pipe 51 and into the ultrasonic atomizer separator 704. The ultrasonic atomizer separator 704 converts the mixed liquid into a mist using ultrasonic vibrations. The mixed liquid mist contains organic solvent mist and water mist. These mists have different mass distributions. For example, the organic solvent mist tends to be lighter than the water mist. The ultrasonic atomizer separator 704 causes the lighter organic solvent mist to move primarily upward, while causing the heavier water mist to move primarily downward, thereby separating the water from the mixed liquid.

[0150] For example, the ultrasonic atomization separator 704 includes an atomization tank, an ultrasonic vibrator, a separation container and a gas supply unit, none of which are shown in the figure. The mixed liquid from the recovery pipe 51 flows into the atomization tank. The ultrasonic vibrator atomizes the mixed liquid in the tank. The mist from the atomization tank flows into the separation container. The mist contains a mist of an organic solvent and a mist of water. The gas supply unit supplies gas from the lower part of the separation container, causing the mist of the lighter organic solvent to move mainly upward and the mist of the heavier water to move mainly downward. The upper end of the separation discharge pipe 705 is connected to the lower part of the separation container. Therefore, the mist of water from the separation container mainly flows into the separation discharge pipe 705. The upper part of the separation container is connected to the upstream end of the first liquid supply pipe 78. The mist of the organic solvent is supplied to the first dehydrator 60 through the first liquid supply pipe 78. In addition, a tank for merging the mist of the organic solvent can also be provided between the separation container and the first liquid supply pipe 78.

[0151] The lower limit of the concentration of the ultrasonic atomizing separator 704 is also very low. For example, the lower limit is approximately zero. Therefore, even if the solvent concentration of the mixed liquid discharged from the processing unit 4 is very low, the second dehydrator 70 can appropriately increase the solvent concentration of the mixed liquid.

[0152] On the other hand, the ultrasonic atomizing separator 704 requires power to vibrate the ultrasonic vibrator and power to supply gas. In addition, when a gas other than air (for example, nitrogen or a rare gas) is used, the cost of the gas is also required, thereby increasing the operating cost.

[0153] In the first embodiment, after the second dehydrator 70 raises the solvent concentration of the mixed liquid to above the lower concentration limit of the first separation membrane 62c, the first dehydrator 60 further increases the solvent concentration of the mixed liquid using the first membrane separator 62. Because membrane separation has a higher energy efficiency than atomization separation, the organic solvent recovery unit 5 can increase the solvent concentration of the mixed liquid more efficiently. Consequently, the organic solvent recovery unit 5 can increase the solvent concentration of the mixed liquid more efficiently. Furthermore, operating costs can be reduced.

[0154] <Third embodiment>

[0155] Figure 7 This is a diagram schematically showing an example of the organic solvent recovery unit 5 according to the third embodiment. Figure 7 In the example, the second dehydrator 70 includes a second membrane separator 72. The mixed liquid discharged from the treatment unit 4 flows into the second membrane separator 72. The second membrane separator 72 separates water from the mixed liquid, 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 identical to the first mixing path 62a, the first water path 62b, and the first separation membrane 62c, respectively.

[0156] A portion of 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 is discharged to the outside (for example, to a wastewater treatment unit of a factory equipment) through the separation discharge pipe 76.

[0157] The solvent concentration of the mixed liquid passing through the second mixing path 72a becomes higher than the solvent concentration of the mixed liquid 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 above the lower limit of the first separation membrane 62c.

[0158] The lower limit value of the concentration of the second separation membrane 72c is lower than the lower limit value of the concentration of the first separation membrane 62c, and is lower than the solvent concentration of the mixed liquid from the treatment unit 4. Here, the case where the first separation membrane 62c and the second separation membrane 72c are both zeolite membranes is described. The lower limit value of the concentration of the zeolite membrane varies depending on the lattice structure of the zeolite membrane. The difference in the lattice structure of the zeolite membrane can be represented by the type (also called structure code). For example, the types of zeolite membranes include LTA type, CHA type and DDR type. The lower limit value of the concentration of the LTA type zeolite membrane is, for example, about 50wt%, the lower limit value of the concentration of the CHA type zeolite membrane is, for example, about 70wt%, and the lower limit value of the concentration of the DDR type zeolite membrane is, for example, about 90wt%.

[0159] As one example, the second separation membrane 72c is an LTA-type zeolite membrane, and the first separation membrane 62c is a CHA-type or DDR-type zeolite membrane. As another example, the second separation membrane 72c is a CHA-type zeolite membrane, and the first separation membrane 62c is a DDR-type zeolite membrane. To more generally describe, 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 lower lower concentration limit than the type 1 zeolite membrane.

[0160] Here, it is also envisaged that the solvent concentration of the mixed liquid from the treatment unit 4 is less than the lower limit of the concentration of the second separation membrane 72c. In this case, a third dehydrator (not shown) can also be set at a position before the second dehydrator 70. The third dehydrator separates water from the mixed liquid from the treatment unit 4, so that the solvent concentration of the mixed liquid increases to above the lower limit of the concentration of the second separation membrane 72c. The third dehydrator supplies the separated mixed liquid to the second dehydrator 70. As an example, the third dehydrator can include a distillation tower 701 and a cooler 702, and can also include an ultrasonic atomization separator 704.

[0161] In addition, the separation constant of the first separation membrane 62c is greater than the separation constant of the second separation membrane 72c. The separation constant referred to herein is an indicator of the solvent concentration of the mixed liquid after the mixed liquid is circulated under specified conditions in a circulation path provided with a membrane separator. Examples of the conditions referred to herein include the initial value of the solvent concentration of the mixed liquid, the flow rate and temperature of the mixed liquid during circulation, and the circulation time. The higher the solvent concentration of the mixed liquid after circulation, the greater the separation constant. Conversely, the greater the separation constant, the greater the amount by which the membrane separator can increase the solvent concentration of the organic solvent.

[0162] As described above, in the third embodiment, the second dehydrator 70 includes the second membrane separator 72. Therefore, compared with distillation and atomization separation, the second dehydrator 70 can separate water from the mixed liquid more efficiently, thereby increasing the solvent concentration of the mixed liquid.

[0163] Furthermore, the lower limit of concentration for the second separation membrane 72c is lower than the lower limit of concentration for the first separation membrane 62c. Therefore, even if the solvent concentration of the mixed liquid from the treatment unit 4 is lower than the lower limit of concentration for the first separation membrane 62c, the organic solvent recovery unit 5 can raise the solvent concentration of the mixed liquid to above the reuse reference value as long as it is above the lower limit of concentration for the second separation membrane 72c. Furthermore, the separation constant for the first separation membrane 62c is greater than the separation constant for the second separation membrane 72c. Therefore, the organic solvent recovery unit 5 can raise the solvent concentration of the mixed liquid to above the reuse reference value more efficiently than if only the second dehydrator 70 were to raise the solvent concentration of the mixed liquid.

[0164] <More Specific First Example of the Organic Solvent Recovery Unit 5>

[0165] Figure 8 This is a diagram schematically showing a first example of a more specific configuration of the organic solvent recovery unit 5 according to the third embodiment.

[0166] Figure 8In the example shown in FIG. 1 , the second dehydrator 70 includes a concentration tank Tk1 and a second circulation unit 71. The downstream end of the recovery pipe 51 is connected to the concentration tank Tk1. The concentration tank Tk1 stores the mixed liquid flowing from the treatment unit 4 through the recovery pipe 51. Here, the solvent concentration of the mixed liquid from the treatment unit 4 is assumed to be greater than the lower limit of the concentration of the second separation membrane 72c (e.g., 50 wt%) and less than the lower limit of the concentration of the first separation membrane 62c (e.g., 70 wt%).

[0167] The second circulation section 71 includes a second membrane separator 72 and a second circulation pipe 73. The second circulation pipe 73 is connected to the concentrator tank Tk1. The second circulation pipe 73 is a pipe that returns the mixed liquid from the concentrator tank Tk1 to the concentrator tank Tk1. In other words, the second circulation pipe 73 forms a second circulation path for the mixed liquid stored in the concentrator tank Tk1 to circulate, flowing out of the concentrator tank Tk1 and returning to the concentrator tank Tk1. Figure 8 In the example of , the upstream end of the second circulation pipe 73 is connected to the bottom of the concentration tank Tk1, and the downstream end of the second circulation pipe 73 is connected to the upper part of the concentration tank Tk1.

[0168] The second membrane separator 72 is provided in the second circulation piping 73. Specifically, the second mixing path 72a of the second membrane separator 72 is inserted into the second circulation piping 73, constituting a part of the second circulation path of the second circulation section 71. Therefore, the mixed liquid passes through the second mixing path 72a. 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. Due to this dehydration, in the second circulation piping 73, the solvent concentration of the mixed liquid after the second membrane separator 72 becomes higher than the solvent concentration of the mixed liquid before the second membrane separator 72. The second circulation section 71 circulates the mixed liquid through the second circulation piping 73, so that the mixed liquid continues to flow into the second membrane separator 72. Thus, the second membrane separator 72 continues to separate water from the mixed liquid. As a result, the solvent concentration of the circulating mixed liquid increases over time.

[0169] The second water path 72b is connected to the upstream end of the separation discharge pipe 76. The separated liquid is discharged to the outside (for example, the waste liquid treatment unit of the factory equipment) through the separation discharge pipe 76. A pressure reducing pump for reducing the pressure in the second water path 72b may also be provided in the separation discharge pipe 76. Figure 8 As shown, a discharge valve 77 is inserted into the separation discharge pipe 76 .

[0170] Figure 8In the example of the embodiment, the second circulation section 71 includes, in addition to the second membrane separator 72 and the second circulation pipe 73, a pump 74 as an example of a liquid feeding section, a first switching valve 751, and a second switching valve 752. The pump 74, the first switching valve 751, and the second switching valve 752 are respectively the same as the pump 64, the first switching valve 651, and the second switching valve 652 in the first embodiment.

[0171] Various sensors can be inserted into the second circulation piping 73. For example, a concentration sensor Sn73, a flow sensor Sn74, and a pressure sensor Sn71 can be inserted into the second circulation piping 73. The concentration sensor Sn73, the flow sensor Sn74, and the pressure sensor Sn71 are the same as the concentration sensor Sn63, the flow sensor Sn64, and the pressure sensor Sn61 in the first embodiment, respectively.

[0172] Figure 8 In the example shown, the upstream end of the first liquid supply pipe 78 is connected to the second circulation pipe 73 between the pump 74 and the first switching valve 751. As an example, the upstream end of the first liquid supply pipe 78 is connected to the second circulation pipe 73 between the pump 74 and the second membrane separator 72. The upstream end of the first liquid supply pipe 78 does not necessarily need to be connected to the second circulation pipe 73, but may also be connected to the concentration tank Tk1. In this case, a pump separate from the pump 74 is provided in the first liquid supply pipe 78. Figure 8 In the example shown in FIG. 1 , a liquid supply valve 79 is inserted into the first liquid supply pipe 78 .

[0173] As described above, the second dehydrator 70 includes a second circulation section 71. The second circulation section 71 circulates the mixed liquid through a second circulation path including the concentration tank Tk1 and the second circulation pipe 73. Specifically, the controller 6 opens the first switching valve 751, the second switching valve 752, and the discharge valve 77, and operates the pump 74. This causes the mixed liquid to continuously flow into the second membrane separator 72. In other words, the mixed liquid that has passed through the second membrane separator 72 repeatedly flows into the second membrane separator 72 through the second circulation path. As a result, the solvent concentration of the mixed liquid in the concentration tank Tk1 increases over time.

[0174] The controller 6 causes the second circulation unit 71 to circulate the mixed liquid until the solvent concentration of the circulating mixed liquid reaches at least the lower limit of the concentration of the first separation membrane 62c. For example, the controller 6 may compare the solvent concentration measured by the concentration sensor Sn 73 with a concentration reference value and stop the circulation of the second circulation unit 71 when the solvent concentration reaches or exceeds the concentration reference value. Specifically, the controller 6 closes the first switching valve 751, the second switching valve 752, and the discharge valve 77, and stops the pump 74. As a result, the mixed liquid having a solvent concentration above the concentration reference value is stored in the concentration tank Tk1. The concentration reference value may be pre-set to a value above the lower limit of the concentration of the first separation membrane 62c (e.g., 70 wt%). For example, the concentration reference value may be set to a value closer to the lower limit of the concentration of the first separation membrane 62c (e.g., 70 wt%) than the reuse reference value (e.g., 99 wt%).

[0175] Alternatively, the controller 6 may use the passage of a designated second dehydration time as a trigger to stop the circulation of the second circulation unit 71. The second dehydration time may be set, for example, to a time period equal to or longer than the time required for the solvent concentration to reach or exceed a reference concentration value. The second dehydration time may be set, for example, to a time period of several tens of minutes or several hours.

[0176] As described above, according to the organic solvent recovery unit 5 of the first example, the solvent concentration of the mixed liquid is increased through the circulation performed by the second circulation unit 71. That is, the mixed liquid repeatedly flows into the second membrane separator 72. Therefore, the size of the second membrane separator 72 (i.e., the size of the second separation membrane 72c) required to increase the solvent concentration of the mixed liquid to the reference concentration value can be reduced.

[0177] <1st Dehydrator>

[0178] Figure 8 In the example shown in FIG. 1 , the downstream end of the first liquid supply pipe 78 is connected to the first membrane separator 62 of the first dehydrator 60. Specifically, the downstream end of the first liquid supply pipe 78 is connected to the upstream portion of the first mixing path 62a of the first membrane separator 62. The upstream end of the second liquid supply pipe 85 is connected to the downstream portion of the first mixing path 62a of the first membrane separator 62. The upstream end of the separation discharge pipe 66 is connected to the first water path 62b of the first membrane separator 62.

[0179] In the first dehydrator 60, the controller 6 opens the second switching valve 752, the liquid feed valve 79, the discharge valve 67, and the liquid feed valve 86, and activates the pump 74. As a result, the mixed liquid from the second dehydrator 70 flows through the first liquid feed pipe 78 into the first membrane separator 62. The first membrane separator 62 separates water from the mixed liquid and discharges the separated liquid to the outside through the separation discharge pipe 66. Simultaneously, the separated mixed liquid (i.e., the recycled liquid) is supplied to the supply tank Tk3 through the second liquid feed pipe 85.

[0180] In the first example, the first dehydrator 60 does not circulate the mixed liquid, and thus the time required for the first dehydrator 60 to operate can be shortened.

[0181] An example of the operation of the organic solvent recovery unit 5 of the first example is the same as Figure 5 That is, the second dehydrator 70 increases the solvent concentration of the mixed liquid to above the lower limit of the concentration of the first separation membrane 62c as described above (step S1), the first dehydrator 60 increases the solvent concentration of the mixed liquid from the second dehydrator 70 to above the reuse reference value as described above (step S2), and the reuse liquid supply unit 89 supplies the mixed liquid (reuse liquid) to the supply tank Tk3 (step S3).

[0182] <More Specific Second Example of the Organic Solvent Recovery Section>

[0183] Figure 9 This is a diagram schematically showing a second example of a more specific structure of the organic solvent recovery unit 5 of the third embodiment. The organic solvent recovery unit 5 of the second example is different from the organic solvent recovery unit 5 of the first example in the structure of the first dehydrator 60. The first dehydrator 60 of the second example substantially has the same Figure 4 The first dehydrator 60 has the same structure as the first dehydrator 60. Figure 9 In the example, a portion of the first circulation pipe 63 and a portion of the second circulation pipe 73 are shared.

[0184] Figure 9 In this example, the first circulation piping 63 includes a downstream common piping 671, a first individual piping 630, and an upstream common piping 672, which is an example of a common circulation piping. The second circulation piping 73 includes the downstream common piping 671, the second individual piping 730, and the upstream common piping 672. Specifically, the downstream common piping 671 and the upstream common piping 672 are shared by the first circulation piping 63 and the second circulation piping 73. The upstream end of the upstream common piping 672 is connected to, for example, the bottom portion of the concentrator tank Tk1, while the downstream end of the downstream common piping 671 is connected to, for example, the top portion of the concentrator tank Tk1. The upstream ends of the first individual piping 630 and the second individual piping 730 are connected to the downstream end of the upstream common piping 672, while the downstream ends of the first individual piping 630 and the second individual piping 730 are connected to the upstream end of the downstream common piping 671.

[0185] The first membrane separator 62 is installed in the first individual pipe 630, and the second membrane separator 72 is installed in the second individual pipe 730. A pump 74 and a second switching valve 752 are inserted into the upstream common pipe 672. Therefore, the pump 74 and the second switching valve 752 are shared by the first circulation section 61 and the second circulation section 71.

[0186] The organic solvent recovery unit 5 is provided with a switching valve unit 790 . Figure 9 In the example, the switching valve section 790 includes a first three-way valve 791 and a second three-way valve 792. The switching valve section 790 switches the circulation path between the first circulation path and the second circulation path. Specifically, the switching valve section 790 switches the first circulation state and the second circulation state described below. The first circulation state refers to a state in which the downstream common pipe 671 and the upstream common pipe 672 are connected to each other through the first individual pipe 630. The second circulation state refers to a state in which the downstream common pipe 671 and the upstream common pipe 672 are connected to each other through the second individual pipe 730. In the first circulation state, the mixed liquid circulates through the first circulation path including the concentration tank Tk1 and the first circulation pipe 63. In the second circulation state, the mixed liquid circulates through the second circulation path including the concentration tank Tk1 and the second circulation pipe 73.

[0187] Figure 9 In the example, the first three-way valve 791 is connected to the upstream end of the downstream common pipe 671, the downstream end of the first individual pipe 630, and the downstream end of the second individual pipe 730. The first three-way valve 791 switches between a first downstream circulation state in which the downstream common pipe 671 is connected to the first individual pipe 630 and a second downstream circulation state in which the downstream common pipe 671 is connected to the second individual pipe 730. The second three-way valve 792 is connected to the downstream end of the upstream common pipe 672, the upstream end of the first individual pipe 630, and the upstream end of the second individual pipe 730. The second three-way valve 792 switches between a first upstream circulation state in which the upstream common pipe 672 is connected to the first individual pipe 630 and a second upstream circulation state in which the upstream common pipe 672 is connected to the second individual pipe 730.

[0188] If the control unit 6 causes the first three-way valve 791 to select the first downstream circulation state and the second three-way valve 792 to select the first upstream circulation state, the mixed liquid circulates through the first circulation path. In other words, the switching valve unit 790 selects the first circulation state. If 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 through the second circulation path. In other words, the switching valve unit 790 selects the second circulation state.

[0189] Similarly, in the second example, the second dehydrator 70 is first activated. Specifically, the controller 6 causes the switching valve unit 790 to select the second circulation state when the solvent concentration of the mixed liquid in the concentration tank Tk1 reaches a second value that is lower than the lower concentration limit of the first separation membrane 62c. The solvent concentration of the mixed liquid in the concentration tank Tk1 can be measured, for example, by a concentration sensor (not shown). With the second circulation state selected, the second dehydrator 70 is initially activated. Specifically, the second dehydrator 70 causes the second circulation unit 71 to circulate the mixed liquid through the second circulation path. The second dehydrator 70 causes the second circulation unit 71 to circulate the mixed liquid until the solvent concentration of the mixed liquid in the concentration tank Tk1 reaches or exceeds the lower concentration limit of the first separation membrane 62c. Then, when the solvent concentration of the mixed liquid reaches a first value that is higher than the lower concentration limit, the controller 6 causes the switching valve unit 790 to select the first circulation state. This activates the first dehydrator 60. Specifically, the first dehydrator 60 causes the first circulation unit 61 to circulate the mixed liquid through the first circulation path. The first dehydrator 60 causes the first circulation unit 61 to circulate the mixed liquid until the solvent concentration of the mixed liquid in the concentration tank Tk1 reaches or exceeds the reuse reference value. As a result, the reused liquid is stored in the concentration tank Tk1.

[0190] Figure 9 In the example shown, the upstream end of the second liquid supply pipe 85 is connected to the first circulation pipe 63 (specifically, the first individual pipe 630). For example, the controller 6 opens the second switching valve 752 and the liquid supply valve 86, selects the second downstream circulation state with the first three-way valve 791, selects the first upstream circulation state with the second three-way valve 792, and activates the pump 74. This supplies the mixed liquid (recycled liquid) in the concentration tank Tk1 to the supply tank Tk3. The upstream end of the second liquid supply pipe 85 can be connected to either the second circulation pipe 73 or the concentration tank Tk1.

[0191] An example of the operation of the organic solvent recovery unit 5 of the second example is also similar to Figure 5 The same. However, an example of a specific action is different. Here, the solvent concentration of the mixed liquid from the treatment unit 4 is lower than the lower limit of the concentration of the first separation membrane 62c. Therefore, first, the second dehydrator 70 increases the solvent concentration of the mixed liquid to above the lower limit of the concentration of the first separation membrane 62c through the circulation implemented by the second circulation section 71 (step S1). Specifically, the control section 6 opens the second switching valve 752 and the discharge valve 77, and allows the switching valve section 790 to select the second circulation state to operate the pump 74. Thus, the mixed liquid circulates through the second circulation path including the concentration tank Tk1 and the second circulation piping 73. Through this circulation, the mixed liquid passes through the second membrane separator 72, so that the solvent concentration of the mixed liquid in the concentration tank Tk1 increases over time.

[0192] When the solvent concentration of the mixed liquid in the concentrator tank Tk1 reaches or exceeds the concentration reference value, the second dehydrator 70 stops circulation, and the first dehydrator 60, through the circulation implemented by the first circulation unit 61, raises the solvent concentration of the mixed liquid to or above the reuse reference value (step S2). Specifically, the controller 6 opens the discharge valve 67 and switches the valve switching unit 790 to the first circulation state. This causes the mixed liquid to circulate through the first circulation path including the concentrator tank Tk1 and the first circulation piping 63. This circulation causes the mixed liquid to pass through the first membrane separator 62, causing the solvent concentration of the mixed liquid in the concentrator tank Tk1 to increase over time. Alternatively, the controller 6 can close the discharge valve 77.

[0193] When the solvent concentration of the mixed liquid in the concentration tank Tk1 reaches or exceeds the reuse reference value, the first circulation unit 61 stops the circulation. Specifically, the control unit 6 closes the second switching valve 752 and the discharge valve 67 and stops the pump 74.

[0194] Next, the reuse liquid supply unit 89 supplies the mixed liquid in the concentration tank Tk1 (ie, the reuse liquid) whose solvent concentration has been increased by the first dehydrator 60 to the supply tank Tk3 (step S3 ).

[0195] As described above, according to the second example, the first dehydrator 60 increases the solvent concentration of the mixed liquid through circulation performed by 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 increase the solvent concentration of the mixed liquid to a value equal to or higher than the reuse reference value can be reduced.

[0196] in addition, Figure 9 In the example of FIG, the pump 74 is shared by the first circulation section 61 and the second circulation section 71. Therefore, the manufacturing cost of the organic solvent recovery section 5 can be reduced.

[0197] <Fourth embodiment>

[0198] Figure 10 This is a diagram schematically showing a first example of a substrate processing apparatus 100 according to a fourth embodiment. The substrate processing apparatus 100 according to the fourth embodiment differs from the substrate processing apparatus 100 according to the first embodiment in the presence or absence of a recovery location switching unit 50. It can also be said that the recovery location switching unit 50 belongs to the organic solvent recovery unit 5. The recovery location switching unit 50 switches between a first dehydration state and a second dehydration state described below. The first dehydration state refers to a state in which the mixed liquid from the processing unit 4 bypasses the second dehydrator 70 and is supplied to the first dehydrator 60. The second dehydration state refers to a state in which the mixed liquid from the processing unit 4 is supplied to the second dehydrator 70.

[0199] The recovery location switching unit 50 includes a recovery pipe 51 and a switching valve unit 520 . Figure 10In the example of , the recovery pipe 51 includes a first dehydration pipe 511 , a second dehydration pipe 512 , and a common recovery pipe 510 . Figure 10 In the example of FIG. 5 , a plurality of common recovery pipes 510 are provided corresponding to a plurality of processing units 4 . Figure 10 In this example, multiple common recovery pipes 510 are provided one-to-one with multiple processing units 4. The upstream end of each common recovery pipe 510 is connected to the corresponding processing unit 4 (specifically, the socket 42). The common recovery pipe 510 is equivalent to the socket-side recovery pipe 424 described above.

[0200] The downstream end portion of the first dehydration pipe 511 is connected to the first dehydrator 60. In addition, the first dehydration pipe 511 is connected to the downstream end portion of each common recovery pipe 510. Figure 10 In the example shown, the first dehydration 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 common recovery piping 510. The upstream ends of the first branch pipes 514 are connected to the downstream ends of the corresponding common recovery piping 510, 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 first dehydration piping 511.

[0201] The downstream end portion of the second dehydration pipe 512 is connected to the second dehydrator 70. In addition, the second dehydration pipe 512 is connected to the downstream end portions of the common recovery pipes 510. Figure 10 In the example shown, the second dehydration 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 common recovery piping 510. The upstream ends of the second branch pipes 516 are connected to the downstream ends of the corresponding common recovery piping 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 second dehydration piping 512.

[0202] Figure 10 In the example of FIG, the switching valve unit 520 includes a switching valve 521 and a switching valve 522. The switching valve unit 520 switches between a state in which the common recovery pipe 510 is connected to the first dehydrator 60 (i.e., a first dehydration state) and a state in which the common recovery pipe 510 is connected to the second dehydrator 70 (i.e., a second dehydration state). Figure 10 In the example of , the plurality of switching valve sections 520 are arranged one to one with the plurality of processing units 4. That is, Figure 10 In the example, a plurality of switching valves 521 are provided one-to-one with a plurality of processing units 4, and a plurality of switching valves 522 are provided one-to-one with a plurality of processing units 4. Each switching valve 521 is inserted into a corresponding first branch pipe 514, and each switching valve 522 is inserted into a corresponding second branch pipe 516.

[0203] Next, the operation of the switching valve unit 520 corresponding to a single treatment unit 4 will be described. When the controller 6 closes the switching valve 521 and opens the switching valve 522, the mixed liquid from the treatment unit 4 flows sequentially through the common recovery pipe 510 and the second dehydration pipe 512, and is supplied to the second dehydrator 70. In other words, the switching valve unit 520 selects the second dehydration state. When the controller 6 opens the switching valve 521 and closes the switching valve 522, the mixed liquid from the treatment unit 4 flows sequentially through the common recovery pipe 510 and the first dehydration pipe 511, and is supplied to the first dehydrator 60. In other words, the switching valve unit 520 selects the first dehydration state.

[0204] The control unit 6 controls the recovery location switching unit 50 based on the solvent concentration of the mixed liquid discharged from the processing unit 4. Specifically, the control unit 6 controls the recovery location switching unit 50 to select the first dehydration state when the solvent concentration of the mixed liquid is a first value that is greater than the lower limit of the concentration of the first separation membrane 62c. The control unit 6 controls the recovery location switching unit 50 to select the second dehydration state when the solvent concentration of the mixed liquid is a second value that is less than the lower limit of the concentration of the first separation membrane 62c. Here, the lower limit of the concentration of the second dehydrator 70 is assumed to be substantially zero.

[0205] Figure 11 This is a flowchart illustrating an example of the operation of the organic solvent recovery unit 5 according to the fourth embodiment. First, the control unit 6 obtains the solvent concentration of the mixed liquid discharged from the treatment unit 4 (step S11: concentration acquisition step). Here, the solvent concentration of the mixed liquid discharged from the treatment unit 4 refers to the solvent concentration of the mixed liquid before the first dehydrator 60 and the second dehydrator 70 are operated. A specific example of the method for obtaining the solvent concentration will be described below.

[0206] The control unit 6 then determines whether the solvent concentration is greater than a specified switching reference value (step S12: concentration determination step). The switching reference value is, for example, pre-set to a value greater than the lower limit concentration value of the first separation membrane 62c. The switching reference value may also be, for example, a value closer to the lower limit concentration value of the first separation membrane 62c than the reuse reference value. The switching reference value may be equal to or less than the concentration reference value.

[0207] When the solvent concentration of the mixed liquid is less than the switching reference value, the second dehydrator 70 separates water from the mixed liquid, thereby increasing the solvent concentration of the mixed liquid (step S13: second dehydrator step). Specifically, the control unit 6 instructs the recovery switching unit 50 to select the second dehydration state. As an example, the control unit 6 closes the switching valve 521 and opens the switching valve 522. As a result, the mixed liquid from the treatment unit 4 is supplied to the second dehydrator 70. In other words, if the solvent concentration of the mixed liquid is less than the switching reference value, the first membrane separator 62 may not be used. Therefore, the organic solvent recovery unit 5 supplies the mixed liquid to the second dehydrator 70, and the second dehydrator 70 ensures that the solvent concentration of the mixed liquid is increased to above the lower limit of the concentration of the first separation membrane 62c.

[0208] After the second dehydrator 70 raises the solvent concentration of the mixed liquid to above the reference concentration value, the first dehydrator 60 separates water from the mixed liquid, further raising the solvent concentration of the mixed liquid (step S14: first dehydrator step). The first dehydrator 60 raises the solvent concentration of the mixed liquid to above the reuse reference value. In other words, the first dehydrator 60 generates reused liquid. Next, the reused liquid supply unit 89 supplies the reused liquid to the supply tank Tk3 (step S15: supply step).

[0209] On the other hand, in step S12, when the solvent concentration of the mixed liquid is above the switching reference value, the first dehydrator 60 separates water from the mixed liquid discharged from the treatment unit 4, thereby increasing the solvent concentration of the mixed liquid (step S14: first dehydrator step). Specifically, the control unit 6 instructs the recovery switching unit 50 to select the first dehydration state. As an example, the control unit 6 opens the switching valve 521 and closes the switching valve 522. In other words, if the solvent concentration of the mixed liquid is above the switching reference value, the highly efficient first membrane separator 62 can be used. Therefore, the organic solvent recovery unit 5 causes the mixed liquid from the treatment unit 4 to bypass the second dehydrator 70 and feed it to the first dehydrator 60.

[0210] The first dehydrator 60 increases the solvent concentration of the mixed liquid to a reuse reference value or more (step S14 ), and the reuse liquid supply unit 89 supplies the reuse liquid to the supply tank Tk3 (step S15 ).

[0211] As described above, when the solvent concentration of the mixed liquid from the treatment unit 4 is high, the second dehydrator 70 does not operate, and the first dehydrator 60 increases the solvent concentration of the mixed liquid. This reduces power consumption by the second dehydrator 70. On the other hand, when the solvent concentration of the mixed liquid from the treatment unit 4 is low, the second dehydrator 70 first increases the solvent concentration of the mixed liquid to a value above the lower limit of the concentration of the first separation membrane 62c. Consequently, the second dehydrator 70 can supply a mixed liquid having a solvent concentration above the lower limit of the concentration of the first separation membrane 62c to the first dehydrator 60.

[0212] Furthermore, if the second dehydrator 70 includes a second membrane separator 72, a third dehydrator may be provided upstream of the second dehydrator 70. The concentration lower limit of the third dehydrator can be lower than the concentration lower limit of the second separation membrane 72c, for example, substantially zero. Furthermore, the recovery switching unit 50 can switch the supply destination of the mixed liquid from the treatment unit 4 between the first dehydrator 60, the second dehydrator 70, and the third dehydrator. For example, when the solvent concentration of the mixed liquid from the treatment unit 4 is less than a second switching reference value, the recovery switching unit 50 supplies the mixed liquid to the third dehydrator. The second switching reference value is set to be greater than the concentration lower limit of the second separation membrane 72c and less than the concentration lower limit of the first separation membrane 62c. The third dehydrator separates water from the mixed liquid, raising the solvent concentration of the mixed liquid to above the concentration lower limit of the second dehydrator 70. The third dehydrator then supplies the separated mixed liquid to the second dehydrator 70. Furthermore, when the solvent concentration of the mixed liquid from the treatment unit 4 is greater than or equal to the second switching reference value and less than or equal to the first switching reference value, the recovery switching unit 50 supplies the mixed liquid to the second dehydrator 70. The first switching reference value is set to be greater than or equal to the lower limit of the concentration of the first separation membrane 62c and less than or equal to the reuse reference value. Furthermore, when the solvent concentration of the mixed liquid from the treatment unit 4 is greater than or equal to the first switching reference value, the recovery switching unit 50 supplies the mixed liquid to the first dehydrator 60.

[0213] <Method for Obtaining Solvent Concentration>

[0214] <Calculation of solvent concentration based on formulation information>

[0215] Next, we will describe an example of a method for obtaining the solvent concentration of the mixed liquid discharged from the processing unit 4. The solvent concentration of the mixed liquid discharged from the processing unit 4 is related to the processing content of the substrate W in the processing unit 4. For example, the processing unit 4 first supplies pure water to the substrate W, and then supplies an organic solvent to the substrate W. During this process, if the processing unit 4 supplies pure water to the substrate W at a high flow rate and for a long time, the solvent concentration of the mixed liquid discharged from the processing unit 4 will become relatively low. On the other hand, if the processing unit 4 supplies the organic solvent to the substrate W at a high flow rate and for a long time, the solvent concentration of the mixed liquid discharged from the processing unit 4 will become relatively high. In this way, the solvent concentration of the mixed liquid discharged from the processing unit 4 is related to the processing content.

[0216] Figure 12 : is a diagram schematically showing an example of the processing unit 4 of the fourth embodiment. Figure 12As shown, the control unit 6 is connected to a storage unit 603. The storage unit 603 is, for example, a nonvolatile storage unit, and as a specific example, a memory or a hard disk. The storage unit 603 stores recipe information D1 that specifies the processing details for the substrate W. The recipe information D1 includes, for example, various types of 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.

[0217] In addition, if Figure 12 As shown, the processing unit 4 may include a plurality of cups 42 . Figure 12 In the example of FIG, a plurality of cups 42 are shown, including a cup 42A, a cup 42B, and a cup 42C. The cups 42A, 42B, and 42C are concentrically arranged. Figure 12 In the example, the support cup 42A is located at the outermost side, the support cup 42C is located at the innermost side, and the support cup 42B is located between the support cup 42A and the support cup 42C.

[0218] The cup lifting mechanism 425 raises and lowers each cup 42. For example, the cup lifting mechanism 425 raises the cup 42A to the upper position and lowers the cups 42B and 42C to the lower position. In this state, the processing liquid scattered from the periphery of the substrate W is caught by the cup 42A. In addition, the cup lifting mechanism 425 raises the cups 42A and 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 caught by the cup 42B. In addition, the cup lifting mechanism 425 raises the cups 42A, 42B, and 42C to the upper position. In this state, the processing liquid scattered from the periphery of the substrate W is caught by the cup 42C.

[0219] Figure 12 In the example shown in FIG. 5 , the processing liquid received by the socket 42C flows into the recovery pipe 51. The processing liquid received by the socket 42A flows into another recovery pipe (not shown), and the processing liquid received by the socket 42B flows into another recovery pipe (not shown).

[0220] This type of processing unit 4 can change the cup 42 that receives the processing liquid according to the type of processing liquid. For example, when pure water is supplied to the substrate W, the cup lifting mechanism 425 only places the cup 42A in the upper position. In this case, the pure water is received by the cup 42A. In addition, when an organic solvent is supplied to the substrate W, the cup lifting mechanism 425 places the cups 42A to 42C in the upper position. In this case, the organic solvent is received by the cup 42C and flows into the recovery pipe 51. That is, in this example, the cup 42C is a cup for the organic solvent, and the recovery pipe 51 is a recovery pipe for the organic solvent. In this way, the processing unit 4 can switch the cup used between the cups 42A to 42C according to the type of processing liquid. This information indicating the position of the cup 42 in each process is also included in the recipe information D1.

[0221] like Figure 12 As shown, the control unit 6 includes a concentration estimating unit 601. The concentration estimating unit 601 reads the recipe information D1 from the storage unit 603. Based on the recipe 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 shows a first example of the recipe information D1.

[0222] [Table 1]

[0223] Recipe Information

[0224]

[0225] Table 1 shows some of the steps involved in processing a substrate W. In Table 1, recipe information D1 includes the number of each step, the rotation speed of the substrate W in each step, the time required for each step, the flow rate of the processing liquid in each step, the type of processing liquid in each step, and the retainer cup used in each step. The retainer cup used can be considered as information indicating the position of the retainer cup 42.

[0226] Figure 13 1 is a diagram schematically showing an example of the status of the processing unit 4 in each step of Table 1. Figure 1 (a) to (b) in 3 Figure 13 (f) in FIG. 1 shows an example of the status of the processing unit 4 in steps 30 to 35 of Table 1.

[0227] In step 30 of Table 1, the substrate W is rotated at 100 rpm (revolutions / minute) by the rotary chuck 41 for 2 seconds, while the rinse liquid nozzle 43b sprays pure water at 2000 mL (milliliters) / min (minute) toward the substrate W. In addition, in step 30, the holder 42A is used. That is, Figure 13 As shown in (a) in FIG. 1 , in step 30, pure water scattered from the periphery of the substrate W is caught by the cup 42A.

[0228] In step 31, the substrate W is rotated at 10 rpm by the rotary chuck 41 for 1 second. In step 31, no processing liquid is supplied to the substrate W. In step 31, the rotation speed of the substrate W is low, so Figure 13 As shown in (b) of Table 1, pure water is maintained on the main surface of substrate W. This process is called a blanketing treatment. Although not shown in Table 1, in practice, between steps 30 and 31, a step may be performed in which the rinse liquid nozzle 43b sprays pure water at 2000 mL / min while the chuck 41 is rotated and the rotation speed is gradually reduced to 10 rpm. The lower the rotation speed of substrate W after the pure water spraying stops, the thicker the pure water film on the main surface of substrate W becomes during the blanketing treatment.

[0229] In step 32, the substrate W is rotated at 10 rpm by the rotary chuck 41 for 1 second, and the cup lifting mechanism 425 switches the cup used from the cup 42A to the cup 42C (see FIG. Figure 13 (c) in the figure.

[0230] In step 33, the substrate W is rotated at 10 rpm by the rotary chuck 41 for 4 seconds, while 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 13 As shown in (d) in FIG, in step 33, the processing liquid (pure water and organic solvent) may flow down from the periphery of the substrate W. In this case, the processing liquid is received by the retainer 42C and flows into the upstream end of the recovery pipe 51.

[0231] In step 34, the spin chuck 41 rotates the substrate W at 1000 rpm for 3 seconds while the IPA nozzle 43c sprays the organic solvent at 100 mL / min toward the main surface of the substrate W. Figure 13 As shown in (e) in FIG. 3 , the organic solvent adhering to the main surface of substrate W flows radially outward and, along with the pure water, scatters outward from the periphery of substrate W. The mixture of organic solvent and pure water is caught by retainer cup 42C and flows into the upstream end of recovery pipe 51. Through steps 33 and 34, the pure water on the main surface of substrate W is replaced with the organic solvent.

[0232] In step 35, the substrate W is rotated at 1000 rpm by the rotary chuck 41 for 2 seconds. In step 35, no processing liquid is supplied to the substrate W. Figure 13 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. As a result, the main surface of the substrate W is dried.

[0233] As described above, the cup 42C is raised to the upper position in step 31 (see also Figure 13 (c) in step 31). Therefore, during steps 31 through 35, cup 42C receives the process liquid (pure water and organic solvent, i.e., a mixed solution). This process liquid flows into the upstream end of recovery pipe 51. Hereinafter, the period from steps 31 through 35 is referred to as the discharge period. The discharge period is the period during which cup 42C can receive the process liquid.

[0234] The solvent concentration (average value) of the mixed liquid flowing into the recovery pipe 51 during the discharge period can be calculated based on the pure water discharge rate and solvent discharge rate described below. The pure water discharge rate is the total amount of pure water flowing into the recovery pipe 51 during the discharge period, that is, the total amount of pure water received by the socket 42C during the discharge period. The solvent discharge rate is the total amount of organic solvent flowing into the recovery pipe 51 during the discharge period, that is, the total amount of organic solvent received by the socket 42C during the discharge period.

[0235] First, the pure water discharge amount is explained. In the example of Table 1, pure water is not supplied during the discharge period (steps 31 to 35). 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 step 31 (see also Figure 13 (c) in step 31). Hereinafter, this amount of pure water will be referred to as the pure water film amount. The thickness of the pure water film on the main surface of substrate W is related to the rotation speed of substrate W at the start of step 31, and therefore the pure water film amount is related to this rotation speed. Furthermore, the start of step 31 can also be considered the time when the switch from retainer cup 42A to retainer cup 42C begins.

[0236] Figure 14 Graph 1 is an example of a distance from each position on the substrate W to the center of the substrate W and a thickness of a pure water liquid film at each position. That is, each curve represents the profile of the pure water liquid level. Figure 14 Graphs G1 to G4 are shown for different rotation speeds of the substrate W. The rotation speed corresponding to graph G1 is the lowest, at 10 rpm. The rotation speed corresponding to graph G2 is the second lowest, at 50 rpm. The rotation speed corresponding to graph G3 is the third lowest, at 100 rpm. The rotation speed corresponding to graph G4 is the highest, at 200 rpm. These graphs G1 to G4 can be obtained through simulation or experimentation.

[0237] The amount of pure water present on the main surface of the substrate W (the amount of pure water film) can be obtained by integrating the thickness of the liquid film of each curve. Therefore, the correspondence between the rotation speed of the substrate W and the amount of pure water film can be obtained in advance. Correspondence information D2 indicating this correspondence is stored in the storage unit 603 (see also). Figure 12 ) The rotation speed at the start time of step 31 is included in the recipe information D1, so the pure water film amount can be calculated based on the rotation speed and the correspondence relationship information D2.

[0238] Furthermore, these curves may also be related to the pure water flow rate in step 30, prior to the coating treatment. Therefore, it is also possible to obtain curves for various flow rates in advance through simulation or experimentation, and use these curves to calculate the pure water film amount. In this case, the correspondence information D2 includes the correspondence between the combination of rotational speed and pure water flow rate and the pure water film amount.

[0239] Next, the solvent discharge amount will be explained. For simplicity, 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 integral of the organic solvent flow rate. Specifically, the solvent discharge amount can be calculated by summing the product of the organic solvent flow rate and the required time (discharge time) for each step. In the example of Table 1, the solvent discharge amount is expressed as 100 × (4 + 3) / 60. Furthermore, since the organic solvent evaporates, the solvent discharge amount can also be calculated by reducing the time integral by a specified ratio to account for this evaporation.

[0240] Table 2 schematically shows a second example of the recipe information D1.

[0241] [Table 2]

[0242] Recipe Information

[0243]

[0244] Table 2 also shows some steps in the processing of the substrate W. Figure 15 This is a diagram schematically showing an example of the status of the processing unit 4 in each step of Table 2. Figure 15 (a) to Figure 15 (e) in Table 2 shows an example of the status of the processing unit 4 in steps 30 to 34 of Table 2.

[0245] In step 30 of Table 2, the substrate W is rotated at 1500 rpm by the rotary chuck 41 for 4 seconds, while the rinse liquid nozzle 43b sprays pure water at 2000 mL / min toward the substrate W. In addition, in step 30, the holder 42A is used. That is, Figure 15 As shown in (a) in FIG. 1 , in step 30, pure water scattered from the periphery of the substrate W is caught by the cup 42A.

[0246] In step 31, the substrate W is rotated at 1500 rpm by the rotary chuck 41 for 2 seconds, while the rinse liquid nozzle 43b sprays pure water at 2000 mL / min onto the substrate W. In addition, in step 31, the cup lifting mechanism 425 switches the cup used from the cup 42C to the cup 42A (see FIG. Figure 15 (b) in FIG. 1 ). As a result, the pure water is received by the socket 42C and flows into the upstream end of the recovery pipe 51 .

[0247] In step 32, the substrate W is rotated at 1500 rpm by the spin chuck 41 for 0.2 seconds, while the rinse liquid nozzle 43b sprays pure water at 2000 mL / min and the IPA nozzle 43c sprays an organic solvent at 250 mL / min. Figure 15 As shown in (c) in FIG. 1 , in the 32nd step as well, the processing liquid scattered from the periphery of the substrate W is received by the retainer cup 42C.

[0248] In step 33, the spin chuck 41 rotates the substrate W at 1500 rpm for 30 seconds while the IPA nozzle 43c sprays the organic solvent at 250 mL / min toward the main surface of the substrate W. Figure 15 As shown in (d) in FIG. 33 , in the same manner, the processing liquid scattered from the periphery of the substrate W is caught by the cup 42C. Through the steps 32 and 33 , the pure water on the main surface of the substrate W is replaced with the organic solvent.

[0249] In step 34, the substrate W is rotated at 1500 rpm by the spin chuck 41 for 30 seconds. In step 34, no processing liquid is supplied to the substrate W. Figure 15 As shown in (e) in FIG. 34 , in the same manner, the organic solvent scattered from the periphery of the substrate W is received by the retainer 42C. In the 34th step, the substrate W is dried.

[0250] As described above, the retainer cup 42C catches the processing liquid (pure water and organic solvent) that splashes from the periphery of the substrate W during steps 31 to 34. This processing liquid flows into the upstream end of the recovery pipe 51. Hereinafter, the period from steps 31 to 34 in Table 2 is referred to as the discharge period.

[0251] In Table 2, during steps 31 and 32, the rinsing liquid nozzle 43b discharges pure water onto 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 discharged from the rinsing liquid nozzle 43b during the discharge period (hereinafter referred to as the pure water discharge rate). The start of step 31 can also be considered the time when the switch from the retainer cup 42A to the retainer cup 42C is initiated.

[0252] The amount of the pure water film is related to the rotation speed of the substrate W as described above. Figure 16 Graph 1 is an example of a distance between each position on the substrate W and the center of the substrate W, and a thickness of the liquid film at each position. Figure 16 The curve G5 is shown in FIG. The rotation speed of the substrate W corresponding to the curve 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 relationship information D2.

[0253] Furthermore, these curves may also be related to the pure water flow rate in step 30, before the socket switching step. Therefore, it is also possible to pre-calculate the curves for each flow rate and use these curves to calculate the pure water film amount. In this case, the correspondence information D2 includes the correspondence between the combination of rotational speed and pure water flow rate and the pure water film amount.

[0254] 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.

[0255] 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 solvent discharge amount is expressed as 250 × (0.2 + 30) / 60. Alternatively, the solvent discharge amount can be calculated by reducing the time-integrated value by a specified ratio.

[0256] Figure 17 4 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 S21: reading step).

[0257] Next, the concentration estimating unit 601 calculates the amount of pure water film based on the recipe information D1 (step S22: pure water film amount calculation step). Specifically, the concentration estimating unit 601 specifies the step of starting to use the support cup 42C from the recipe information D1 (for example, step 31 of Table 1 or Table 2), and specifies the rotation speed of the substrate W at the start time of the step from the recipe information D1. The concentration estimating unit 601 can specify the rotation speed of the substrate W in the step as the rotation speed of the substrate W at the start time of the step, or can specify the rotation speed of the substrate W in the step before the step as the rotation speed of the substrate W at the start time of the step. Subsequently, the concentration estimating unit 601 reads the corresponding relationship information D2 from the storage unit 603. Then, the concentration estimating unit 601 calculates the amount of pure water film based on the specified rotation speed and the corresponding relationship information D2 (refer to Figure 13 (c) or Figure 15 (b) in the figure.

[0258] In addition, 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 also specify the pure water flow rate before the step of starting to use the support cup 42C from the recipe information D1, and calculate the pure water film amount based on the specified rotation speed and pure water flow rate, and the correspondence information D2.

[0259] Furthermore, based on the recipe information D1, the concentration estimating unit 601 calculates the total amount of pure water ejected during the discharge period (the pure water ejection amount) (step S23: pure water ejection amount calculation step). Specifically, the concentration estimating unit 601 identifies the step in which pure water is ejected using the socket 42C from the recipe information D1 and calculates the pure water ejection amount in that step by multiplying the pure water flow rate by the required time. The concentration estimating unit 601 then calculates the total ejection amount in each step as the pure water ejection amount.

[0260] Furthermore, based on the recipe information D1, the concentration estimating unit 601 calculates the total amount of organic solvent discharged during the discharge period (the solvent discharge amount) (step S24: solvent discharge amount calculation step). Specifically, the concentration estimating unit 601 identifies the step in which the organic solvent is discharged using the retainer cup 42C from the recipe information D1 and calculates the discharge amount of the organic solvent in that step by multiplying the solvent flow rate by the required time. The concentration estimating unit 601 then calculates the total discharge amount of the organic solvent in each step as the solvent discharge amount. Alternatively, the concentration estimating unit 601 can calculate the solvent discharge amount by reducing this total by a specified ratio.

[0261] Next, the concentration estimating unit 601 divides the solvent discharge amount by the sum of the pure water film amount, the pure water ejection amount, and the solvent discharge amount to calculate the solvent concentration (step S25: solvent concentration calculation step).

[0262] As described above, the concentration estimating unit 601 calculates the solvent concentration based on the recipe information D1. Therefore, a concentration sensor for measuring the solvent concentration is not required, and the manufacturing cost of the substrate processing apparatus 100 can be reduced.

[0263] Furthermore, in the example described above, the concentration estimating unit 601 determines the amount of pure water film based on the rotation 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 rotation speed of the substrate W, it can determine the solvent concentration with higher accuracy.

[0264] In addition, the recovery pipe connected to the support cup 42C is sometimes branched into multiple branches according to the type of processing liquid. For example, when the support cup 42C is used for organic solvents and other first processing liquids, the support cup 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. When the first processing liquid is supplied to the substrate W, the switching valve unit connects the pipe for the first processing liquid to the support cup 42C, and when the organic solvent is supplied to the substrate W, the recovery pipe 51 is connected to the support cup 42C. In this case, a plurality of discharge ports are set on the support cup 42C. In this case, the discharge port can also be set in the recipe information D1. Moreover, the concentration estimation unit 601 can also specify the step of setting the discharge port for the organic solvent (i.e., the recovery pipe 51), and calculate the pure water film amount, the pure water spray amount and the solvent discharge amount in the same way as described above.

[0265] <Solvent Concentration Measurement Using a Concentration Sensor>

[0266] 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 recipe 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 also be measured using a concentration sensor.

[0267] Figure 18 This diagram schematically illustrates a second example of a substrate processing apparatus 100 according to the fourth embodiment. In this second example, a concentration sensor Sn5 is provided in each common recovery pipe 510. The concentration sensor Sn5 measures the solvent concentration of the mixed liquid flowing through the common recovery pipe 510 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.

[0268] The control unit 6 controls the recovery location switching unit 50 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 switching reference value. When the solvent concentration is less than the switching reference value, the control unit 6 controls the recovery location switching unit 50 to select the second dehydration state. When the solvent concentration is greater than the switching reference value, the control unit 6 controls the recovery location switching unit 50 to select the first dehydration state.

[0269] 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 switching unit 50, thereby more appropriately supplying the mixed liquid to the first dehydrator 60 or the second dehydrator 70.

[0270] <Fifth embodiment>

[0271] Figure 191 is a diagram schematically showing an example of a substrate processing apparatus 100 according to a fifth embodiment. The substrate processing apparatus 100 according to the fifth embodiment differs from the substrate processing apparatus 100 according to the fourth embodiment in the configuration of a recovery location switching unit 50 .

[0272] The recovery switching unit 50 switches between the first dehydration state and the second dehydration state. In the fifth embodiment, the first dehydration state refers to a state in which the mixed liquid obtained by merging the mixed liquids from the plurality of treatment units 4 is supplied to the first dehydrator 60, and the second dehydration state refers to a state in which the mixed liquid obtained by merging the mixed liquids from the plurality of treatment units 4 is supplied to the second dehydrator 70.

[0273] The recovery switching section 50 includes a recovery pipe 51 and a switching valve section 520. The recovery pipe 51 includes a common recovery pipe 517, a first dehydration pipe 518, and a second dehydration pipe 519. The common recovery pipe 517 is connected to each processing unit 4 (cup 42) through each cup-side recovery pipe 424. In the common recovery pipe 517, the mixed liquids from multiple processing units 4 converge. The downstream end of the common recovery pipe 517 is connected to the upstream end of the first dehydration pipe 518 and the upstream end of the second dehydration pipe 519. The downstream end of the first dehydration pipe 518 is connected to the first dehydrator 60, and the downstream end of the second dehydration pipe 519 is connected to the second dehydrator 70.

[0274] Figure 19 In the example of , the switching valve unit 520 includes a switching valve 523 and a switching valve 524. The switching valve unit 520 switches the state in which the common recovery pipe 517 is connected to the first dehydrator 60 (first dehydration state) and the state in which the common recovery pipe 517 is connected to the second dehydrator 70 (second dehydration state). Figure 19 In the example of , the switching valve 523 is inserted in the first dehydration pipe 518 , and the switching valve 524 is inserted in the second dehydration pipe 519 .

[0275] When the controller 6 closes the switching valve 523 and opens the switching valve 524, the mixed liquid from the treatment unit 4 flows sequentially through the common recovery pipe 517 and the second dehydration pipe 519 and is supplied to the second dehydrator 70. When the controller 6 opens the switching valve 523 and closes the switching valve 524, the mixed liquid from the treatment unit 4 flows sequentially through the common recovery pipe 517 and the first dehydration pipe 518 and is supplied to the first dehydrator 60.

[0276] The control unit 6 controls the recovery location switching unit 50 based on the solvent concentration of the mixed liquid flowing through the common recovery pipe 517 . Figure 19In the example, a concentration sensor Sn51 is provided in the common recovery pipe 517. The concentration sensor Sn51 measures the solvent concentration of the mixed liquid flowing through the common recovery pipe 517 and outputs the measurement result to the control unit 6. An example of the configuration of the concentration sensor Sn51 is the same as that of the concentration sensor Sn5. When the solvent concentration measured by the concentration sensor Sn51 is a second value less than the lower concentration limit of the first separation membrane 62c, the control unit 6 causes the recovery location switching unit 50 to select the second dehydration state. When the solvent concentration is a first value greater than the lower concentration limit of the first separation membrane 62c, the control unit 6 causes the recovery location switching unit 50 to select the first dehydration state. As a more specific example, the control unit 6 may compare the solvent concentration measured by the concentration sensor Sn51 with a switching reference value. When the solvent concentration is less than the switching reference value, the control unit 6 causes the recovery location switching unit 50 to select the second dehydration state. When the solvent concentration is greater than the switching reference value, the control unit 6 causes the recovery location switching unit 50 to select the first dehydration state.

[0277] As described above, according to the fifth embodiment, the organic solvent recovery unit 5 switches the supply destination of the mixed liquid based on the solvent concentration of the mixed liquid obtained by merging the mixed liquids from the multiple processing units 4. Specifically, in the fifth embodiment, a single recovery destination switching unit 50 is provided for each of the multiple processing units 4. Therefore, compared to the fourth embodiment, in which multiple recovery destination switching units 50 are provided one-to-one with the multiple processing units 4, the manufacturing cost of the organic solvent recovery unit 5 can be reduced.

[0278] Furthermore, in the above example, since the concentration sensor Sn51 measures the solvent concentration, the control unit 6 can obtain the solvent concentration of the mixed liquid with higher accuracy. Consequently, the control unit 6 can more effectively control the recovery switching unit 50, thereby more effectively supplying the mixed liquid to the first dehydrator 60 or the second dehydrator 70. Furthermore, according to the fifth embodiment, a single concentration sensor Sn51 is provided for each of the multiple processing units 4. Therefore, compared to the fourth embodiment, in which multiple concentration sensors Sn5 are provided one-to-one with multiple processing units 4, the manufacturing cost of the organic solvent recovery unit 5 can be reduced.

[0279] As described above, the organic solvent recovery apparatus (organic solvent recovery unit 5), substrate processing apparatus 100, and organic solvent recovery method have been described in detail. However, all aspects of the description are merely illustrative, and the present invention is not limited thereto. Furthermore, the various variations described above may be combined and applied as long as they do not conflict with each other. Furthermore, any variations not illustrated should be understood as conceivable forms that do not depart from the scope of the present invention.

[0280] 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 purification tank, a purification circulation pipe connected to the purification tank, a switching valve inserted into the purification circulation pipe, a pump, and a filter. Thus, the organic solvent recovery unit 5 can supply reused liquid with a low impurity concentration to the supply tank Tk3.

[0281] [Explanation of Symbols]

[0282] 100 substrate processing device

[0283] 4 processing units

[0284] 41 Substrate holding part (rotating chuck)

[0285] 42 Cup

[0286] 430 ejection part

[0287] 50 Recycling Switching Department

[0288] 51 Recovery piping

[0289] 6 Control Unit

[0290] 60 No. 1 dehydrator

[0291] 62 No. 1 membrane separator

[0292] 62c 1st separation membrane

[0293] 63 1st circulation piping

[0294] 630 1st individual piping

[0295] 64, 74 Liquid delivery unit (pump)

[0296] 672 Common circulation piping (upstream common piping)

[0297] 70 Second Dehydrator

[0298] 701 Distillation Tower

[0299] 704 Ultrasonic Atomization Separator

[0300] 72 Second membrane separator

[0301] 72c Second separation membrane

[0302] 73 Second circulation piping

[0303] 730 Second individual piping

[0304] 78 1st liquid supply piping

[0305] 790 switching valve unit

[0306] 85 2nd liquid supply piping

[0307] D1 formula information

[0308] D2 correspondence information

[0309] Sn5, Sn51 concentration sensors

[0310] Tk1 Concentration Tank

[0311] Tk3 supply tank

[0312] W substrate.

Claims

1. An organic solvent recovery device, comprising: a recovery pipe for flowing a mixed liquid of an organic solvent and water discharged from a processing unit for processing a substrate; a first dehydrator comprising a first membrane separator including a first separation membrane having an applicable range of solvent concentration, the first membrane separator separating water from the mixed liquid having a solvent concentration above the lower limit of the applicable range, i.e., the lower concentration limit, thereby increasing the solvent concentration of the mixed liquid; and The second dehydrator is arranged at a position closer to the front of the first dehydrator, separates water from the mixed liquid discharged through the recovery pipe, increases the solvent concentration of the mixed liquid to above the lower limit of concentration, and supplies the mixed liquid with a solvent concentration above the lower limit of concentration to the first dehydrator.

2. The organic solvent recovery device according to claim 1, wherein The second dehydrator includes a first liquid feeding pipe for feeding the mixed liquid to the first dehydrator. The first dehydrator includes a second liquid feeding pipe for feeding the mixed liquid to a supply tank for supplying the mixed liquid to the processing unit, and The first membrane separator is connected to the downstream end of the first liquid supply pipe and the upstream end of the second liquid supply pipe.

3. The organic solvent recovery device according to claim 1, wherein The first dehydrator comprises: a concentration tank for storing the mixed solution; a first circulation pipe connected to the concentration tank and provided with the first membrane separator; and The liquid delivery portion is provided in the first circulation pipe.

4. The organic solvent recovery device according to any one of claims 1 to 3, wherein The second dehydrator includes at least one of a distillation tower and an ultrasonic atomizing separator.

5. The organic solvent recovery device according to claim 1 or 2, wherein The second dehydrator includes a second membrane separator having a second separation membrane, and The lower limit of the applicable range of the solvent concentration of the second separation membrane is smaller than the lower limit of the concentration of the first separation membrane. The separation constant of the first separation membrane is greater than the separation constant of the second separation membrane.

6. The organic solvent recovery device according to claim 5, wherein The second dehydrator comprises: a concentration tank for storing the mixed liquid flowing in from the recovery pipe; a second circulation pipe connected to the concentration tank and provided with the second membrane separator; and The liquid delivery portion is provided in the second circulation pipe.

7. The organic solvent recovery device according to claim 6, It also has a switching valve unit, and The first dehydrator includes a first circulation pipe connected to the concentration tank, The first circulation piping includes: A common circulation pipe is provided with the liquid delivery portion; and a first separate pipe provided with the first membrane separator; The second circulation piping includes: The common circulation piping; and a second separate pipe provided with the second membrane separator; The switching valve unit switches between a first circulation state and a second circulation state, wherein the first circulation state refers to a state in which the mixed liquid circulates through the concentration tank and the first circulation pipe, and the second circulation state refers to a state in which the mixed liquid circulates through the concentration tank and the second circulation pipe.

8. The organic solvent recovery device according to claim 7, The invention is provided with a control unit, which allows the switching valve unit to select the second circulation state when the solvent concentration of the mixed liquid is a second value less than the concentration lower limit value of the first separation membrane, and allows the switching valve unit to select the first circulation state when the solvent concentration of the mixed liquid is a first value greater than the concentration lower limit value.

9. The organic solvent recovery device according to any one of claims 1 to 3, further comprising: a recovery switching portion for switching between a second dehydration state and a first dehydration state, wherein the second dehydration state is a state in which the mixed liquid discharged from the processing unit is supplied to the second dehydrator, and the first dehydration state is a state in which the mixed liquid discharged from the processing unit bypasses the second dehydrator and is supplied to the first dehydrator; and The control unit allows the recovery point switching unit to select the second dehydration state when the solvent concentration of the mixed liquid is a second value less than the concentration lower limit value of the first separation membrane, and allows the recovery point switching unit to select the first dehydration state when the solvent concentration of the mixed liquid is a first value greater than the concentration lower limit value.

10. The organic solvent recovery device according to claim 9, A storage unit storing recipe information indicating the processing content of the substrate by the processing unit is provided, and The control unit calculates a solvent concentration of the mixed liquid discharged from the processing unit based on the recipe information.

11. The organic solvent recovery device according to claim 10, wherein The processing unit comprises: a substrate holding portion for holding and rotating the substrate; a discharge portion that sequentially discharges pure water and an organic solvent toward the main surface of the substrate held by the substrate holding portion; and a support cup having a cylindrical shape surrounding the substrate holding portion and receiving liquid scattered from the periphery of the substrate; and The upstream end of the recovery pipe is connected to the socket. The recipe 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 a pure water film amount, the pure water film amount being an amount of pure water on the main surface of the substrate. The control unit calculates the pure water film amount based on the rotation speed of the substrate specified according to the recipe information and the corresponding relationship information, and calculates the solvent concentration of the mixed liquid discharged from the 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.

12. The organic solvent recovery device according to claim 9, A concentration sensor is provided for measuring the solvent concentration of the mixed liquid, and The control unit controls the recovery location switching unit based on the solvent concentration of the mixed liquid measured by the concentration sensor.

13. The organic solvent recovery device according to any one of claims 1 to 3, comprising: Recycling switching unit; and A control unit controls the recycling switching unit; and The recovery piping comprises: a plurality of cup-side recovery pipes connected to the plurality of processing units; a common recovery pipe connected to the downstream ends of the plurality of cup-side recovery pipes; a first dehydration pipe connecting the downstream end of the common recovery pipe to the first dehydrator; and a second dehydration pipe connecting the downstream end of the common recovery pipe to the second dehydrator; The recovery switching unit switches between a first dehydration state and a second dehydration state, wherein the first dehydration state is a state in which the common recovery pipe is connected to the first dehydrator through the first dehydration pipe, bypassing the second dehydrator, and supplying the mixed liquid to the first dehydrator; and the second dehydration state is a state in which the common recovery pipe is connected to the second dehydrator through the second dehydration pipe, and supplying the mixed liquid to the second dehydrator. The control unit allows the recovery location switching unit to select the first dehydration state when the solvent concentration of the mixed liquid flowing through the common recovery pipe is a first value greater than the concentration lower limit value of the first separation membrane, and allows the recovery location switching unit to select the second dehydration state when the solvent concentration of the mixed liquid flowing through the common recovery pipe is a second value less than the concentration lower limit value.

14. A substrate processing apparatus comprising: The organic solvent recovery device according to any one of claims 1 to 3, and The processing unit.

15. A method for recovering an organic solvent, comprising: In a first step, water is separated from a mixed solution of an organic solvent and water discharged from a processing unit for processing a substrate, thereby increasing the solvent concentration of the mixed solution; and In a second step, after the first step, water is separated from the mixed liquid using a first membrane separator including a first separation membrane having an applicable range of solvent concentration, thereby increasing the solvent concentration of the mixed liquid; and In the first step, the solvent concentration of the mixed liquid is increased to a lower limit value of the applicable range of the first separation membrane, that is, a concentration lower limit value or more.

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