Substrate processing apparatus

Abstract

To provide a substrate processing apparatus capable of separating a chemical liquid from a mixed liquid of the chemical liquid and an organic solvent with low energy.SOLUTION: The substrate processing apparatus includes a processing unit, a recovery pipe 60a, and a recovery unit 6. The processing unit causes the mixed liquid of the chemical liquid and the organic solvent to act on the main surface of the substrate. The recovery pipe 60a has an upstream end portion connected to the processing unit. The mixed liquid from the processing unit flows into the recovery pipe 60a. The recovery unit 6 includes a separation membrane 72c that separates the chemical liquid from the mixed liquid supplied through the recovery pipe 60a and increases the concentration of the organic solvent in the mixed liquid.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Single-wafer substrate processing apparatuses for processing substrates have been disclosed in the past (for example, Patent Document 1). In Patent Document 1, the substrate processing apparatus supplies an etching solution containing an oxidizing agent, a catalyst, and a moisture adjuster to the substrate to etch a molybdenum film on the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-114569 Summary of the Invention [Problem to be solved by the invention]

[0004] The etching solution after being used to etch a substrate is discarded, for example. When the moisture adjuster is an organic solvent, a large amount of energy is required to dispose of the etching solution containing a large amount of organic solvent. Therefore, it is possible to reduce the organic solvent content in the etching solution by separating the organic solvent from the etching solution, for example, by distillation. However, the energy required for distillation is large, and the running cost is high.

[0005] Therefore, an object of the present disclosure is to provide a substrate processing apparatus that can separate a chemical solution from a mixed solution of a chemical solution and an organic solvent with low energy. [Means for solving the problem]

[0006] A first aspect is a substrate processing apparatus comprising: a processing unit that applies a mixed liquid of a chemical liquid and an organic solvent to a main surface of a substrate; a recovery pipe having an upstream end connected to the processing unit and into which the mixed liquid from the processing unit flows; and a recovery unit including a separation membrane that separates the chemical liquid from the mixed liquid supplied through the recovery pipe and increases the concentration of the organic solvent in the mixed liquid.

[0007] A second aspect is a substrate processing apparatus according to the first aspect, wherein the chemical liquid is a liquid that etches an etching target on the main surface of the substrate, the etching target containing a metal, and the recovery unit further includes a first metal filter that captures the metal in the mixed liquid.

[0008] A third aspect is a substrate processing apparatus according to the second aspect, wherein the recovery unit includes a tank into which the mixed liquid flows through the recovery piping, and a circulation piping having an upstream end and a downstream end connected to the tank and having the separation membrane and the first metal filter inserted therein, and the first metal filter is provided upstream of the separation membrane.

[0009] A fourth aspect is a substrate processing apparatus according to the second or third aspect, comprising a recycling pipe through which the mixed liquid with an increased concentration of the organic solvent flows from the recovery unit to the processing unit, and a second metal filter inserted in the recycling pipe to capture metals in the mixed liquid. [Effects of the Invention]

[0010] According to the first aspect, the separation membrane separates the chemical liquid from the mixed liquid, which allows the chemical liquid to be separated from the mixed liquid with lower energy than, for example, distillation.

[0011] According to the second aspect, the mixed liquid can be purified.

[0012] According to the third aspect, the amount of metals that flow into the separation membrane can be reduced, and therefore, deterioration of the separation membrane can be reduced.

[0013] According to the fourth aspect, a cleaner mixed liquid can be supplied to the processing unit. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a plan view schematically showing an example of the configuration of a substrate processing apparatus. [Figure 2] FIG. 2 is a block diagram schematically illustrating an example of the internal configuration of a control unit. [Figure 3] FIG. 2 is a diagram schematically illustrating an example of the configuration of a processing unit. [Figure 4] FIG. 2 is a diagram schematically illustrating an example of the configuration of a recovery unit. [Figure 5] FIG. 10 is a diagram schematically illustrating a first modified example of the configuration of a substrate processing apparatus. [Figure 6] FIG. 10 is a view schematically showing a second modified example of the configuration of the substrate processing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the drawings, the dimensions and numbers of each part are exaggerated or simplified as necessary for ease of understanding. Parts having similar configurations and functions are assigned the same reference numerals, and duplicate explanations will be omitted below.

[0016] In the following description, the same components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions of them may be omitted to avoid duplication.

[0017] Furthermore, in the following description, even if ordinal numbers such as "first" or "second" are used, these terms are used for convenience to facilitate understanding of the contents of the embodiments, and are not limited to the order that may result from these ordinal numbers.

[0018] When expressions indicating relative or absolute positional relationships (e.g., "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) are used, unless otherwise specified, the expressions not only strictly represent the positional relationship but also represent a state in which there is a relative displacement in terms of angle or distance within a range in which tolerance or equivalent functionality is obtained. When expressions indicating an equal state (e.g., "identical," "equal," "homogeneous," etc.) are used, the expressions not only represent a state in which there is strict quantitative equality but also represent a state in which there is a difference in which tolerance or equivalent functionality is obtained, unless otherwise specified. When expressions indicating a shape (e.g., "rectangular shape" or "cylindrical shape," etc.) are used, the expressions not only represent a geometrically strict shape but also represent a shape with, for example, irregularities or chamfers within a range in which equivalent effects are obtained, unless otherwise specified. When the expressions "comprise," "include," "have," "includes," "includes," or "have" are used to describe one component, the expressions are not exclusive expressions that exclude the presence of other components. When the phrase "at least one of A, B, and C" is used, the phrase includes A only, B only, C only, any two of A, B, and C, and all of A, B, and C.

[0019] <Overall configuration of substrate processing equipment> FIG. 1 is a plan view schematically showing an example of the configuration of a substrate processing apparatus 100. The substrate processing apparatus 100 is a single-wafer processing apparatus that processes substrates W one by one. The substrate W is, for example, a semiconductor wafer such as a silicon semiconductor. The substrate W has, for example, a disk shape. The diameter of the substrate W is, for example, about 300 mm, and the thickness of the substrate W is, for example, not less than about 0.5 mm and not more than about 3 mm. Note that the substrate W may be a substrate other than a semiconductor wafer.

[0020] 1, the substrate processing apparatus 100 includes an indexer block 110, a processing block 120, a recovery unit (recovery apparatus) 6, and a control unit 90. The processing block 120 is a section that mainly processes substrates W, and the indexer block 110 is a section that transports the substrates W between the outside of the substrate processing apparatus 100 and the processing block 120. The recovery unit 6 is a section that receives, from the processing block 120, a processing liquid that has been used to process the substrates W.

[0021] The indexer block 110 includes a load port 111 and a first transport part 112. A substrate container (hereinafter referred to as a carrier) C that is carried in from outside is placed on the load port 111. The carrier C accommodates a plurality of substrates W, for example, arranged at intervals from each other in the vertical direction. In the example of FIG. 1, a plurality of load ports 111 are arranged.

[0022] The first transport unit 112 is a transport robot, and may also be called an indexer robot. The first transport unit 112 transports unprocessed substrates W from the carrier C to the processing block 120. The processing block 120 can perform processing on the substrates W. The first transport unit 112 transports processed substrates W from the processing block 120 to the carrier C of the load port 111.

[0023] In the example of FIG. 1, the processing block 120 includes a plurality of processing units 1 and a second transport part 122. The second transport part 122 is a transport robot that transports substrates W between the first transport part 112 and the plurality of processing units 1. In the example of FIG. 1, the processing block 120 also includes a receiver 123. The receiver 123 is, for example, a shelf on which a plurality of substrates W can be placed in a vertically aligned state. The first transport part 112 transports unprocessed substrates W from the receiver 123 to the processing unit 1. The processing unit 1 supplies a processing liquid to the substrate W to process the substrate W. The configuration of the processing unit 1 will be described later. The second transport part 122 transports processed substrates W from the processing unit 1 to the receiver 123. The first transport part 112 transports processed substrates W from the receiver 123 to the carrier C of the load port 111.

[0024] 1, a plurality of (for example, four) processing units 1 are arranged to surround the second transport section 122 in a plan view. The second transport section 122 may also be called a center robot. At each position in a plan view, a plurality of processing units 1 may be stacked vertically. In other words, a plurality of (four in the figure) towers TW each made up of a plurality of processing units 1 stacked vertically may be arranged to surround the second transport section 122.

[0025] The recovery unit 6 is connected to the processing unit 1 via a pipe 60. The processing liquid used to process the substrate W in the processing unit 1 is supplied to the recovery unit 6 through the pipe 60. An example of a specific configuration of the recovery unit 6 will be described in detail later.

[0026] The control unit 90 comprehensively controls the substrate processing apparatus 100. Specifically, the control unit 90 controls the first transport unit 112, the second transport unit 122, the processing unit 1, and the recovery unit 6. FIG. 2 is a block diagram schematically illustrating an example of the internal configuration of the control unit 90. The control unit 90 is an electronic circuit and includes, for example, a data processing unit 91 and a memory unit 92. In the specific example of FIG. 2, the data processing unit 91 and the memory unit 92 are connected to each other via a bus 93. The data processing unit 91 may be, for example, an arithmetic processing device such as a CPU (Central Processor Unit). The memory unit 92 may include a non-transitory memory unit (e.g., a ROM (Read Only Memory)) 921 and a temporary memory unit (e.g., a RAM (Random Access Memory)) 922. The control unit 90 may also be connected to a non-transitory memory unit (memory or a hard disk) (not shown). The non-transitory memory unit 921 may store, for example, a program that defines the processing to be performed by the control unit 90. The data processing unit 91 executes the program, allowing the control unit 90 to perform the processing defined in the program. Of course, some or all of the processing performed by the control unit 90 may be performed by hardware such as a dedicated logic circuit.

[0027] <Processing unit overview> Fig. 3 is a diagram schematically illustrating an example of the configuration of a processing unit 1. It is not necessary that all processing units 1 belonging to the substrate processing apparatus 100 have the configuration illustrated in Fig. 3. It is sufficient that at least one processing unit 1 of the substrate processing apparatus 100 has the configuration illustrated in Fig. 3.

[0028] As will be described in detail later, the processing unit 1 supplies a processing liquid to the main surface (e.g., the upper surface) of the substrate W to process the main surface of the substrate W. The processing liquid includes, for example, an etching liquid. In this case, the processing unit 1 etches an etching target on the main surface of the substrate W. The etching target includes, for example, a metal. The etching target may also be a metal compound such as a metal nitride film or a metal oxide film. The metal compound may be, for example, TiN, TaN, TaAlN, or TiC. A nanosheet FET (Field Effect Transistor) structure in the process of being manufactured may be formed on the main surface of the substrate W. A nanosheet FET is also called a ribbon FET. In this structure, for example, a plurality of fin structures, which will be described below, are arranged at intervals in a direction perpendicular to the main surface of the substrate W. The fin structure includes a sheet-shaped semiconductor layer and an insulating film surrounding the semiconductor layer. A sacrificial film is provided around the fin structure. In this case, the sacrificial film is the etching target.

[0029] The processing unit 1 includes a substrate holder 2 and a discharge unit 3. In the example of FIG. 3, the processing unit 1 also includes a chamber 10. The chamber 10 has a box-like shape, and its internal space corresponds to a processing space in which a substrate W is processed. The chamber 10 is provided with an openable / closable loading / unloading port (not shown). The second transport unit 122 loads an unprocessed substrate W into the chamber 10 through the loading / unloading port, and loads a processed substrate W out of the chamber 10 through the loading / unloading port.

[0030] The substrate holder 2 is provided in the chamber 10 and holds the substrate W in a horizontal position while rotating the substrate W around a rotation axis Q1. The horizontal position here means that the thickness direction of the substrate W is aligned with the vertical direction. The rotation axis Q1 is an axis that passes through the center of the substrate W and is aligned with the vertical direction. Such a substrate holder 2 may also be called a spin chuck. Here, the main surface of the substrate W on which a pattern (e.g., a fin structure) is formed corresponds to the top surface of the substrate W.

[0031] The substrate holder 2 may hold the substrate W using a chucking method such as a mechanical chuck, a vacuum chuck, an electrostatic chuck, or a Bernoulli chuck. In the example of FIG. 3, the substrate holder 2 is a mechanical chuck type and includes a spin base 21, chuck pins 22, and a rotation driver 23. The spin base 21 has a plate-like shape (e.g., a disk shape) and is disposed with its thickness direction aligned vertically. The multiple chuck pins 22 are disposed on the spin base 21 at equal intervals along the circumferential direction about the rotation axis Q1. The multiple chuck pins 22 are disposed so as to be displaceable between a holding position and a release position, which will be described below. The holding position is a position where the chuck pins 22 abut against the periphery of the substrate W. The multiple chuck pins 22 hold the substrate W by stopping at their respective holding positions (see FIG. 3). The release position is a position where each chuck pin 22 is separated from the substrate W. The plurality of chuck pins 22 stop at their respective release positions, thereby releasing the holding of the substrate W by the plurality of chuck pins 22. The substrate holding unit 2 also includes a pin driving unit (not shown) that displaces the chuck pins 22. The pin driving unit includes a driving source such as a motor and an air cylinder, and is controlled by the control unit 90.

[0032] The rotation drive unit 23 includes a shaft 231 and a motor 232. The upper end of the shaft 231 is connected to the lower surface of the spin base 21, and the shaft 231 extends from the lower surface of the spin base 21 along a rotation axis Q1. The motor 232 is controlled by the control unit 90 to rotate the shaft 231 about the rotation axis Q1. This causes the spin base 21, chuck pins 22, and substrate W to rotate integrally about the rotation axis Q1.

[0033] The discharge unit 3 discharges various processing liquids toward the main surface (here, the upper surface) of the substrate W held by the substrate holder 2. The processing liquid that has landed on the main surface of the substrate W flows radially outward as the substrate W rotates, and is scattered outward from the main surface of the substrate W. In this way, the processing liquid acts on the main surface of the substrate W.

[0034] A mixture of a chemical and an organic solvent is used as one of the processing liquids. The chemical is a liquid that etches the etching target. Specifically, the chemical may be dilute hydrofluoric acid, a mixture of hydrochloric acid, hydrogen peroxide, and water (SC2), a mixture of ammonia water, hydrogen peroxide, and water (SC1), or diluted hydrogen peroxide. Other etching liquids may also be used as the chemical. The concentration (vol%) of dilute hydrofluoric acid may be, for example, approximately 1:5 to 1:2000 in terms of hydrogen fluoride:pure water. The concentration (vol%) of SC1 may be, for example, approximately 1:1:5 to 1:1:100 in terms of sulfuric acid:hydrogen peroxide:pure water. The concentration (vol%) of SC2 may be, for example, approximately 1:1:5 to 1:1:100 in terms of ammonia water:hydrogen peroxide:pure water.

[0035] The organic solvent may be isopropyl alcohol or methanol. By mixing such an organic solvent with the chemical solution, the conductivity of the mixed solution can be improved. The concentration of the organic solvent in the mixed solution (hereinafter referred to as solvent concentration) may be, for example, 5 vol% or more and 80 vol% or less, or 30 vol% or more and 70 vol% or less. When such a mixed solution acts on the etching target of the substrate W, the supply of electrons increases, activating the etching reaction. This allows the etching rate to be improved.

[0036] The surface tension of the organic solvent may be higher than that of the chemical liquid, in which case the mixed liquid can easily penetrate between patterns on the substrate W (for example, between fin structures), enabling the etching target to be etched more quickly.

[0037] The molecular diameter of the organic solvent molecules is larger than the molecular diameter (maximum value) of the chemical molecules. Therefore, as will be described in detail later, the recovery unit 6 can use the difference in molecular diameter to separate the chemical liquid from the mixed liquid after processing the substrate W.

[0038] 3, the discharge unit 3 includes a nozzle 4. The nozzle 4 is, for example, a straight nozzle that discharges the processing liquid in the form of a liquid column. The nozzle 4 is provided in the chamber 10 above the substrate W held by the substrate holder 2. The nozzle 4 discharges the processing liquid toward the main surface of the substrate W.

[0039] In the example of FIG. 3, multiple nozzles 4 are provided, and one of the nozzles 4 is a nozzle 4a for a mixed liquid. The downstream end of a mixing pipe 41a is connected to the nozzle 4a, and the upstream end of the mixing pipe 41a is connected to a mixing section 45a. The downstream end of a chemical supply pipe 43a and the downstream end of a solvent supply pipe 44a are also connected to the mixing section 45a. In the example of FIG. 3, the chemical supply pipe 43a includes multiple individual supply pipes 431 corresponding to the multiple types of liquid that make up the chemical liquid. Here, as an example, SC2 is used as the chemical liquid. For this purpose, an individual supply pipe 431 through which hydrochloric acid flows, an individual supply pipe 431 through which hydrogen peroxide solution flows, and an individual supply pipe 431 through which pure water flows are provided. An organic solvent flows through the solvent supply pipe 44a.

[0040] The mixing unit 45a mixes the chemical solution flowing in from the chemical solution supply pipe 43a and the organic solvent flowing in from the solvent supply pipe 44a. The mixing unit 45a may be a multiple valve. The mixing unit 45a includes, for example, a chemical solution mixing valve 451a and a solvent mixing valve 452a. In the example of FIG. 3, the chemical solution mixing valve 451a includes multiple individual mixing valves 451 corresponding to the multiple liquids that make up the chemical solution. For example, it includes an individual mixing valve 451 for hydrochloric acid, an individual mixing valve 451 for hydrogen peroxide, and an individual mixing valve 451 for pure water. Each individual mixing valve 451 passes the corresponding liquid toward the mixing pipe 41a at a flow rate corresponding to its own opening. The solvent mixing valve 452a passes the organic solvent toward the mixing pipe 41a at a flow rate corresponding to its own opening. The chemical solution mixing valve 451a and the solvent mixing valve 452a are controlled by the control unit 90. The mixing section 45a is not necessarily limited to a multiple valve, but may be configured by a connection section between pipes and a flow rate adjustment valve connected to each pipe.

[0041] A supply valve 42a is inserted in the mixing pipe 41a and controls the opening and closing of the mixing pipe 41a. The supply valve 42a is controlled by the control unit 90.

[0042] In the example of FIG. 3, the nozzle 4a is provided so as to be movable by a movement drive unit 46a. The movement drive unit 46a moves the nozzle 4a between a processing position and a standby position, which will be described below. The processing position is a position where the nozzle 4a ejects the mixed liquid, and is, for example, a position vertically facing the center of the substrate W (see FIG. 3). The standby position is a position where the nozzle 4a does not eject the mixed liquid, and is, for example, a position radially outward from the substrate W. The movement drive unit 46a includes, for example, a drive source such as a motor, and a power transmission unit that connects the drive source and the nozzle. The power transmission unit includes, for example, an arm rotation mechanism or a ball screw mechanism.

[0043] In the example of FIG. 3, a nozzle 4b for a rinse liquid is also shown as a nozzle 4. The nozzle 4b is connected to the downstream end of a supply pipe 41b, the upstream end of which is connected to a rinse liquid supply source. The rinse liquid is, for example, pure water. A supply valve 42b and a flow rate control valve 43b are inserted in the supply pipe 41b. The supply valve 42b switches the opening and closing of the supply pipe 41b, and the flow rate control valve 43b adjusts the flow rate of the rinse liquid flowing through the supply pipe 41b. The supply valve 42b and the flow rate control valve 43b are controlled by the control unit 90. The nozzle 4b is movable by a movement drive unit 46b. The movement drive unit 46b moves the nozzle 4b between a processing position and a standby position. The movement drive unit 46b has, for example, a configuration similar to that of the movement drive unit 46a and is controlled by the control unit 90.

[0044] The processing unit 1 supplies the mixed liquid to the substrate W, and then supplies a rinse liquid to the substrate W. This allows the mixed liquid on the main surface of the substrate W to be washed away by the rinse liquid.

[0045] In the example of FIG. 4, a nozzle 4c for an organic solvent is also shown as the nozzle 4. The nozzle 4c is connected to the downstream end of a supply pipe 41c, and the upstream end of the supply pipe 41c is connected to an organic solvent supply source. A supply valve 42c and a flow rate control valve 43c are inserted in the supply pipe 41c. The supply valve 42c switches the opening and closing of the supply pipe 41c, and the flow rate control valve 43c adjusts the flow rate of the organic solvent flowing through the supply pipe 41c. The supply valve 42c and the flow rate control valve 43c are controlled by the control unit 90. The nozzle 4c is movable by a movement drive unit 46c. The movement drive unit 46c moves the nozzle 4c between a processing position and a standby position. The movement drive unit 46c has a configuration similar to that of the movement drive unit 46a, for example, and is controlled by the control unit 90.

[0046] The processing unit 1 supplies the rinse liquid to the substrate W, and then supplies the organic solvent to the substrate W. This allows the rinse liquid on the main surface of the substrate W to be washed away by the organic solvent. Here, the volatility of the organic solvent is higher than the volatility of the rinse liquid.

[0047] After the supply of the organic solvent, the processing unit 1 dries the substrate W. For example, the substrate holder 2 increases the rotation speed of the substrate W, thereby drying the substrate W (so-called spin drying).

[0048] In the example of FIG. 3, the processing unit 1 is provided with multiple guards 5. Each guard 5 has a cylindrical shape with the rotation axis Q1 as its central axis and surrounds the substrate holder 2. The multiple guards 5 are provided concentrically. Each guard 5 is provided so that it can be raised and lowered by a lifting drive unit 52. The lifting drive unit 52 raises and lowers each guard 5 between an upper position and a lower position. The upper position is a position where the upper end of the guard 5 is located above the substrate W held by the substrate holder 2. In this state, the guard 5 can receive processing liquid splashed from the periphery of the substrate W. For example, the lifting drive unit 52 includes a drive source such as a motor and a power transmission unit such as a cam mechanism. The lifting drive unit 52 is controlled by the control unit 90.

[0049] Each guard 5 is used depending on the type of processing liquid. For example, the outer guard 5 is used for the mixed liquid. Specifically, with the lifting drive unit 52 positioning only the outer guard 5 in the upper position, the nozzle 4a ejects the mixed liquid toward the main surface of the substrate W. As a result, the mixed liquid splashed from the periphery of the substrate W is received by the outer guard 5 and flows down along the inner circumferential surface of the guard 5.

[0050] In the example of FIG. 3, a cup 53 is provided corresponding to each guard 5. The cup 53 has an annular (e.g., annular) recess (groove) surrounding the rotation axis Q1. Each cup 53 receives the processing liquid that has flowed down the inner circumferential surface of the corresponding guard 5. The upstream end of a pipe 60 is connected to, for example, the bottom of each cup 53. The processing liquid received in each cup 53 is discharged to the outside of the processing unit 1 through the pipe 60.

[0051] The mixed liquid received by the outer guard 5 is received in the corresponding cup 53 and flows into the corresponding pipe 60. Hereinafter, the pipe 60 into which the mixed liquid flows is also referred to as recovery pipe 60a.

[0052] <Recovery Unit 6> FIG. 4 is a diagram schematically illustrating an example of the configuration of the recovery unit 6. The recovery unit 6 is connected to the processing unit 1 through a recovery pipe 60a for the mixed liquid. In the example of FIG. 4, a recovery valve 61 is inserted in the recovery pipe 60a. The recovery valve 61 switches the recovery pipe 60a between open and closed states. The recovery valve 61 is controlled by the control unit 90.

[0053] The recovery unit 6 is supplied with the mixed liquid after being used to process the substrate W in the processing unit 1 (hereinafter also referred to as the post-processing processing liquid) through a recovery pipe 60a. The recovery unit 6 includes a membrane separator 72. The membrane separator 72 separates the chemical liquid from the post-processing mixed liquid and increases the solvent concentration of the mixed liquid. An example of the configuration of the recovery unit 6 will now be described in detail.

[0054] In the example of Fig. 4, the recovery unit 6 includes a tank Tk1 and a circulation unit 7. The downstream end of the recovery pipe 60a is connected to the tank Tk1. Therefore, the mixed liquid after processing from the processing unit 1 flows into the tank Tk1 through the recovery pipe 60a. The tank Tk1 stores the mixed liquid.

[0055] A buffer tank (not shown) may be inserted in the recovery pipe 60a. In this case, a liquid delivery unit such as a pump and a supply valve may be inserted in the recovery pipe 60a between the buffer tank and the tank Tk. In this case, the processed mixed liquid from the processing unit 1 is temporarily stored in the buffer tank and then supplied from the buffer tank to the tank Tk1.

[0056] The circulation unit 7 includes a circulation pipe 71, a membrane separator 72, a liquid delivery unit 73, and a circulation valve 74. The circulation pipe 71 forms a circulation path through which the mixed liquid stored in the tank Tk1 flows out of the tank Tk1 and returns to the tank Tk1. The upstream end of the circulation pipe 71 is connected to, for example, the bottom of the tank Tk1, and the downstream end of the circulation pipe 71 is connected to, for example, the top of the tank Tk1.

[0057] The membrane separator 72 is inserted into the circulation pipe 71. The membrane separator 72 includes a housing, which contains a first path 72a, a second path 72b, and a separation membrane 72c. The first path 72a is inserted into the circulation pipe 71 and forms part of the circulation path of the circulation unit 7. Therefore, the mixed liquid passes through the first path 72a. The separation membrane 72c separates the first path 72a and the second path 72b. The separation membrane 72c is a membrane that allows the chemical liquid in the mixed liquid to pass through and almost completely blocks the organic solvent. A portion of the chemical liquid in the mixed liquid that flows into the first path 72a passes through the separation membrane 72c and flows into the second path 72b.

[0058] The separation membrane 72c is a microporous membrane that separates the chemical solution from the mixed solution based on the difference in molecular diameter between the chemical solution and the organic solvent. The molecular diameter of the chemical solution is smaller than that of the organic solvent. The pore size of the separation membrane 72c is set so that the separation membrane 72c substantially blocks each molecule of the organic solvent while allowing the molecules of the chemical solution to pass through. Therefore, each molecule of the chemical solution can pass through the pores of the separation membrane 72c, while each molecule of the organic solvent hardly passes through the pores of the separation membrane 72c. The difference between the molecular diameter of the organic solvent and the molecular diameter of the chemical solution may be, for example, 0.5 Å or more, or even 1 Å or more. For example, the molecular diameter of isopropyl alcohol is approximately 6.2 Å, and the largest molecular diameter of the molecules of the compounds that make up the chemical solution (e.g., SC1, SC2, or ammonia water) is approximately 5.0 Å or less.

[0059] The separation membrane 72c may be a zeolite membrane, an organic separation membrane, or a CNT (carbon nanotube) separation membrane. The zeolite membrane is, for example, a tetrahedral (SiO4) 4- ) and (AlO4) 5- The separation membrane 72c has a crystalline structure in which carbon nanotubes are interconnected. The organic separation membrane is, for example, an organic membrane such as polyvinyl alcohol, chitosan, or polyimide. The CNT separation membrane is, for example, a membrane obtained by adding carbon nanotubes to a membrane such as polyamide. Alternatively, a two-dimensional material may be used as the material for the separation membrane 72c. The two-dimensional material is a material composed of one atomic layer, and may be, for example, molybdenum sulfide (MoS2) or a composite atomic layer compound of an early transition metal (such as titanium or vanadium) and a light element (carbon or nitrogen). Alternatively, the separation membrane 72c may be made of a metal organic framework (MOF) material or a carbon material (such as graphene or graphene oxide). In this example, a zeolite membrane is used as the separation membrane 72c.

[0060] The upstream end of a discharge pipe 78 is connected to the second path 72b. The liquid (mainly the chemical liquid) of the mixed liquid that has passed through the separation membrane 72c is discharged to the outside (for example, a wastewater treatment unit of a factory facility) through the discharge pipe 78. A pressure reducing pump that reduces the pressure in the second path 72b may be provided in the discharge pipe 78. As shown in FIG. 4, a discharge valve 79 may be inserted in the discharge pipe 78. The discharge valve 79 switches the discharge pipe 78 between open and closed states. The discharge valve 79 is controlled by a control unit 90.

[0061] The liquid delivery unit 73 is inserted into the circulation pipe 71. In the example of FIG. 4, the liquid delivery unit 73 is provided at a position upstream of the membrane separator 72. The liquid delivery unit 73 is, for example, a pump, and delivers the mixed liquid from the upstream end of the circulation pipe 71 to the downstream end. The circulation valve 74 is inserted into the circulation pipe 71. In the example of FIG. 4, the circulation valve 74 is provided at a position upstream of the liquid delivery unit 73. The circulation valve 74 switches the circulation pipe 71 between open and closed. The liquid delivery unit 73 and the circulation valve 74 are controlled by the control unit 90.

[0062] In the example of FIG. 4, the recovery unit 6 also includes a temperature adjustment unit 75. The temperature adjustment unit 75 is controlled by the control unit 90 and adjusts the temperature of the mixed liquid. For example, the temperature adjustment unit 75 may be a heater that heats the mixed liquid. As a specific example, the temperature adjustment unit 75 may be an electric resistance type or a radiation type heater. In the example of FIG. 4, the temperature adjustment unit 75 is provided in the tank Tk1 and heats the mixed liquid in the tank Tk1. In the example of FIG. 4, the temperature adjustment unit 75 is provided at the bottom and side of the tank Tk1. The temperature adjustment unit 75 adjusts the temperature of the mixed liquid to a temperature suitable for separation by the membrane separator 72. As a specific example, the temperature adjustment unit 75 adjusts the temperature of the mixed liquid to 70 degrees Celsius or higher. The temperature adjustment unit 75 may also be provided in the circulation pipe 71.

[0063] 4, a flow meter Sn2 is provided in the circulation pipe 71. The flow meter Sn2 outputs a signal corresponding to the flow rate through the circulation pipe 71 to the control unit 90. The control unit 90 controls the liquid delivery unit 73 based on the signal received from the flow meter Sn2 so that the flow rate of the mixed liquid falls within a range suitable for separation in the membrane separator 72.

[0064] When the control unit 90 operates the liquid delivery unit 73 while opening the circulation valve 74 and the discharge valve 79, the mixed liquid circulates through a circulation path including the tank Tk1 and the circulation pipe 71. As a result, the mixed liquid flows into the membrane separator 72. The membrane separator 72 separates the chemical liquid from the mixed liquid that has flowed in and sends the chemical liquid to the discharge pipe 78. The separated mixed liquid continues to circulate through the circulation pipe 71. Due to this separation, the concentration of the organic solvent in the mixed liquid immediately after the membrane separator 72 (hereinafter referred to as the solvent concentration) becomes higher in the circulation pipe 71 than the solvent concentration in the mixed liquid immediately before the membrane separator 72. Because the circulation unit 7 circulates the mixed liquid through the circulation pipe 71, the mixed liquid continues to flow into the membrane separator 72. Therefore, the membrane separator 72 continues to separate the chemical liquid from the mixed liquid. As a result, the chemical liquid continues to flow from the discharge pipe 78. Because the solvent concentration in the chemical liquid flowing through the discharge pipe 78 is low, disposal of the chemical liquid can be simplified.

[0065] Meanwhile, the solvent concentration of the circulating mixed solution increases over time. As a result, the solvent concentration of the mixed solution in the tank Tk1 increases. This mixed solution with an increased solvent concentration may be reused as an organic solvent. For example, the circulation unit 7 circulates the mixed solution at least until the solvent concentration of the mixed solution in the tank Tk1 reaches or exceeds the reuse reference value. The reuse reference value is set in advance, for example. The reuse reference value may be, for example, 80 vol% or more, 85 vol% or more, or 90 vol% or more. Hereinafter, a mixed solution having a solvent concentration equal to or greater than the reuse reference value is also referred to as a concentrated solution.

[0066] In the example of FIG. 4, the recovery unit 6 includes a concentration sensor Sn1. The concentration sensor Sn1 measures the solvent concentration of the mixed liquid and outputs an electrical signal indicating the measurement result to the control unit 90. In the example of FIG. 4, the concentration sensor Sn1 is provided in the circulation pipe 71. As a specific example, the concentration sensor Sn1 is provided downstream of the membrane separator 72. The concentration sensor Sn1 may also be provided in the tank Tk1. The control unit 90 operates the circulation unit 7 at least until the solvent concentration measured by the concentration sensor Sn1 becomes equal to or greater than the reuse reference value.

[0067] In the example of FIG. 4, the tank Tk1 of the recovery unit 6 is connected to the processing unit 1 through a reuse pipe 65. In the example of FIG. 4, the upstream end of the reuse pipe 65 is connected to, for example, the bottom of the tank Tk1. The downstream end of the reuse pipe 65 may be connected to the mixing section 45a. In this case, the reuse pipe 65 functions as the solvent supply pipe 44a. A supply valve 66 and a liquid delivery section 67 may be inserted in the reuse pipe 65. The supply valve 66 switches the reuse pipe 65 between open and closed states. The liquid delivery section 67 delivers the concentrated solution from the tank Tk1 toward the mixing section 45a. The supply valve 66 and the liquid delivery section 67 are controlled by the control section 90.

[0068] With the concentrated liquid stored in the tank Tk1, the control unit 90 opens the supply valve 66 and operates the liquid delivery unit 67. This causes the concentrated liquid in the tank Tk1 to be supplied to the processing unit 1 through the reuse pipe 65. In this way, the organic solvent in the mixed liquid subjected to processing in the processing unit 1 is reused by the processing unit 1 while being contained in the concentrated liquid, thereby reducing the amount of organic solvent used.

[0069] The mixed liquid used to process the substrate W in the processing unit 1 may contain components of the etching target. If the etching target contains a metal, the mixed liquid contains the metal (ions). That is, the mixed liquid dissolves the etching target (e.g., a sacrificial film) of the substrate W, and the metal contained in the etching target dissolves in the mixed liquid. The metal includes, for example, at least one of titanium, tantalum, and aluminum. If the concentrated liquid contains a large amount of such metals and is then used again to process the substrate W, this may result in a decrease in etching performance.

[0070] 4, the recovery unit 6 also includes a first metal filter 76. In the example of FIG. 4, the first metal filter 76 is inserted into the circulation pipe 71. In the example of FIG. 3, the first metal filter 76 is provided upstream of the membrane separator 72.

[0071] The first metal filter 76 captures metals (ions) in the mixed solution. The first metal filter 76 includes, for example, an ion exchange resin and a filter housing that houses the ion exchange resin. The ion exchange resin is a synthetic resin having ion exchange groups. When the chemical solution flows into the first metal filter 76, the ion exchange groups are exchanged with metal ions in the chemical solution. As a result, the metal ions are captured by the ion exchange resin. The ion exchange groups of the ion exchange resin may include functional groups that form complexes with the metal ions. This allows the first metal filter 76 to capture metal ions with higher selectivity.

[0072] Alternatively, the first metal filter 76 may include an adsorbent and a filter housing that accommodates the adsorbent. The adsorbent adsorbs metal ions in the chemical solution. The adsorbent may include at least one of activated carbon, zeolite, and silica gel, for example.

[0073] In the example of FIG. 4, the first metal filter 76 is provided upstream of the membrane separator 72. Therefore, the mixed liquid passes through the first metal filter 76 before flowing into the membrane separator 72. In other words, the concentration of metals in the mixed liquid (hereinafter referred to as the metal concentration) is reduced by the first metal filter 76 before the mixed liquid flows into the membrane separator 72. This reduces the possibility of metal ions adhering to the separation membrane 72c of the membrane separator 72. This reduces deterioration of the separation membrane 72c.

[0074] In the example of FIG. 4, the mixed liquid continues to flow into the first metal filter 76 while it is circulating. Therefore, the first metal filter 76 continues to capture metals in the mixed liquid. Therefore, the metal concentration of the circulating mixed liquid decreases over time. By circulating the mixed liquid through the first metal filter 76, the metal concentration can be further reduced.

[0075] Next, an example of the operation of the recovery unit 6 will be described. The treated mixed liquid from the processing unit 1 flows into the tank Tk1. First, the control unit 90 controls the temperature adjustment unit 75 to adjust the temperature of the mixed liquid to a temperature suitable for separation in the membrane separator 72. Next, the control unit 90 operates the liquid delivery unit 73 while opening the circulation valve 74 and the discharge valve 79. This causes the mixed liquid to circulate through a circulation path including the tank Tk1 and the circulation piping 71. If a decompression pump is provided in the discharge piping 78, the control unit 90 also operates the decompression pump. The chemical liquid separated from the mixed liquid by the membrane separator 72 is discharged to the outside through the discharge piping 78, and the solvent concentration in the circulating mixed liquid increases over time.

[0076] When the first metal filter 76 is provided, the metal concentration in the circulating mixed liquid decreases over time.

[0077] The control unit 90 circulates the mixed liquid through the circulation unit 7 at least until the solvent concentration of the mixed liquid in the tank Tk1 becomes equal to or greater than the reuse standard value. As a result, a concentrated liquid having a solvent concentration equal to or greater than the reuse standard value is stored in the tank Tk1. The control unit 90 may also circulate the mixed liquid through the circulation unit 7 until the metal concentration of the mixed liquid in the tank Tk1 becomes equal to or less than the metal standard value.

[0078] The recovery unit 6 supplies the concentrated liquid in the tank Tk1 to the processing unit 1 through the reuse pipe 65. Specifically, the control unit 90 opens the supply valve 66 and activates the liquid delivery unit 67. This causes the concentrated liquid in the tank Tk1 to be supplied to the processing unit 1. Note that the processing unit 1 may stop the operation of the circulation unit 7 before supplying the concentrated liquid to the processing unit 1, or may supply the concentrated liquid to the processing unit 1 in parallel with the operation of the circulation unit 7.

[0079] As described above, in the substrate processing apparatus 100, the separation membrane 72c separates the chemical from the mixed solution of the chemical and the organic solvent recovered from the processing unit 1. This allows the substrate processing apparatus 100 to separate the chemical from the mixed solution with less energy than, for example, distillation.

[0080] The separated chemical solution is discharged through the discharge pipe 78. Since the solvent concentration of this chemical solution is low, disposal of the chemical solution can be further simplified.

[0081] On the other hand, the solvent concentration of the mixed liquid becomes higher. In the example of Fig. 4, the recovery unit 6 supplies the concentrated liquid as the organic solvent to the processing unit 1 through the reuse pipe 65. In other words, the organic solvent is reused. Therefore, the amount of organic solvent used can be reduced. In other words, the substrate processing apparatus 100 contributes to saving the use of organic solvent.

[0082] Furthermore, in the above example, the recovery unit 6 includes a first metal filter 76. The first metal filter 76 captures the metal to be etched contained in the mixed solution. Therefore, even if the metal concentration in the mixed solution increases after etching the substrate W, the first metal filter 76 can reduce the metal concentration in the mixed solution. This allows the recovery unit 6 to supply a cleaner concentrated solution to the processing unit 1. Therefore, the processing unit 1 can supply a mixed solution containing a cleaner concentrated solution to the substrate W, and can etch the substrate W while maintaining a high etching rate.

[0083] 5 is a diagram schematically illustrating a first alternative configuration of the substrate processing apparatus 100. In the example of FIG. 5, the substrate processing apparatus 100 is provided with a supply tank Tk2. The supply tank Tk2 stores an organic solvent (concentrated liquid). The downstream end of the reuse pipe 65 is connected to, for example, the top of the supply tank Tk2, and the upstream end of the solvent supply pipe 44a is connected to, for example, the bottom of the supply tank Tk2. The supply tank Tk2 can function as a buffer tank. A liquid delivery unit (not shown) may be inserted into the solvent supply pipe 44a.

[0084] 6 is a diagram schematically illustrating a second modified example of the configuration of the substrate processing apparatus 100. In the second modified example, the substrate processing apparatus 100 further includes a second metal filter 77. The second metal filter 77 is inserted in the recycling pipe 65. The second metal filter 77 captures metals (ions) in the concentrated liquid. An example of the second metal filter 77 may be the same as the first metal filter 76.

[0085] According to the second modification, the metal concentration in the concentrate can be further reduced by the second metal filter 77. Therefore, the recovery unit 6 can supply an even cleaner concentrate to the treatment unit 1.

[0086] As described above, the substrate processing apparatus 100 and the substrate processing method have been described in detail. However, the above description is merely an example in all respects, and this disclosure is not limited thereto. Furthermore, the various modifications described above can be applied in combination as long as they are not mutually contradictory. Furthermore, it is understood that many modifications not exemplified can be envisioned without departing from the scope of this disclosure. [Explanation of symbols]

[0087] 1 Processing Unit 100 Substrate processing apparatus 6 Recovery Unit 60a Recovery piping 65 Recycled pipe 71 Circulation piping 72c separation membrane 76 First metal filter 77 Second Metal Filter Tk1 Tank W substrate

Claims

1. a processing unit for applying a mixed liquid of a chemical solution and an organic solvent to a main surface of the substrate; a recovery pipe having an upstream end connected to the processing unit and into which the mixed liquid from the processing unit flows; a recovery unit including a separation membrane that separates the chemical solution from the mixed solution supplied through the recovery pipe and increases the concentration of the organic solvent in the mixed solution; A substrate processing apparatus comprising:

2. The substrate processing apparatus according to claim 1 , the chemical liquid is a liquid that etches an etching target on the main surface of the substrate, the etching target includes a metal, The substrate processing apparatus, wherein the recovery unit further includes a first metal filter that captures metals in the mixed liquid.

3. 3. The substrate processing apparatus according to claim 2, The recovery unit comprises: a tank into which the mixed liquid flows through the recovery pipe; a circulation pipe having an upstream end and a downstream end connected to the tank, the circulation pipe having the separation membrane and the first metal filter interposed therein; Including, The substrate processing apparatus, wherein the first metal filter is provided upstream of the separation membrane.

4. 4. The substrate processing apparatus according to claim 2, wherein: a recycle pipe through which the mixed liquid having an increased concentration of the organic solvent flows from the recovery unit to the treatment unit; a second metal filter inserted in the reuse pipe to capture metals in the mixed liquid; A substrate processing apparatus comprising:

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