Particle removal method and substrate processing device

Abstract

Disclosed is a particle removal method with which particles in a processing liquid for processing a substrate are removed. The method includes: a step for circulating a processing liquid through a processing liquid flow path; a step for supplying fine bubbles to the processing liquid circulating through the processing liquid flow path; a step for causing particles in the processing liquid circulating through the processing liquid flow path to adhere to the fine bubbles in the processing liquid flow path; and a step for separating and collecting the fine bubbles to which the particles adhere from the processing liquid circulating through the processing liquid flow path. The processing liquid flow path may be provided with a pipe that has a bent portion. In this case, in the step for collecting, fine bubbles guided to a branch flow path that is branched from the pipe in a tangential direction of the bent portion may be collected.

Description

Particle Removal Method and Substrate Processing Apparatus Related Application

[0001] This application claims priority based on Japanese Patent Application No. 2024-163581 filed on September 20, 2024, and the entire contents of this application are hereby incorporated by reference.

[0002] The present invention relates to a method for removing particles in a processing liquid for processing a substrate, and a substrate processing apparatus having a configuration for removing particles in the processing liquid.

[0003] Patent Document 1 discloses an immersion-type substrate processing apparatus having a configuration for removing particles in a processing liquid. Specifically, bubbles are discharged into the processing liquid by a bubbler disposed at the bottom of the processing tank, and the bubbles in the processing liquid are removed by a bubble removal unit provided in the processing liquid circulation system. Particles in the processing liquid are adsorbed by the bubbles and removed together with the bubbles. Thereby, particles can be removed without using a filter. The bubble removal unit removes the bubbles contained in the processing liquid by swirling the processing liquid and collecting the bubbles at the swirling center.

[0004] Japanese Patent Application Laid-Open No. 2006-100493

[0005] The bubbler disposed in the processing tank has a configuration in which a plurality of porous discharge portions that discharge bubbles are connected to the tip of a pipe through which gas passes (see paragraph 0034 of Patent Document 1). The bubbles discharged from such a bubbler are normal bubbles having a diameter of about several millimeters and are considered to be so-called millibubbles. Millibubbles rapidly rise in the processing liquid and mostly burst and disappear at the water surface.

[0006] Therefore, the residence time in the processing liquid is short, and thus the time for adsorbing particles is short. In addition, since many bubbles burst and disappear at the liquid surface of the processing liquid tank, the ratio of the bubbles remaining until they reach the bubble removal unit is small. Accordingly, the ratio of the particles removed together with the bubbles in the bubble removal unit is small, so the particle removal efficiency is not necessarily high.

[0007] Therefore, one embodiment of this invention provides a particle removal method and a substrate processing apparatus that can efficiently remove particles from a processing liquid.

[0008] One embodiment of this invention provides a method for removing particles from a processing liquid used to process a substrate. This method includes the steps of: flowing a processing liquid through a processing liquid channel; supplying fine bubbles to the processing liquid flowing through the processing liquid channel; causing particles in the processing liquid flowing through the processing liquid channel to adhere to the fine bubbles within the processing liquid channel; and separating and collecting the fine bubbles to which the particles have adhered from the processing liquid flowing through the processing liquid channel.

[0009] In one embodiment, the processing liquid flow path includes a pipe having a bend. The collection step involves collecting the fine bubbles that are guided into a branch flow path that branches off from the pipe in the tangential direction of the bend.

[0010] In one embodiment, the piping includes a supply pipe that supplies the processing liquid from a processing liquid tank that stores the processing liquid to the substrate. The bend includes a supply pipe bend provided in the supply pipe.

[0011] In one embodiment, the supply piping is connected to a nozzle that discharges the processing liquid toward the substrate. The supply piping bend includes a pre-nozzle bend provided immediately before the nozzle.

[0012] Typically, no further bends are provided in the supply piping between the bend before the nozzle and the nozzle outlet.

[0013] In one embodiment, the nozzle is located within a processing chamber that demarcates a processing space for processing the substrate. The nozzle's front bend is provided within the processing chamber.

[0014] In one embodiment, the bent portion includes a spiral tube provided in the piping.

[0015] In one embodiment, the curved portion includes an upwardly convex curved portion.

[0016] In one embodiment, the collection step involves applying an electric field (typically a DC electric field) to the processing liquid flowing through the processing liquid channel to change the trajectory of the fine bubbles in the processing liquid, thereby guiding the fine bubbles to a branch channel branching off from the processing liquid channel and separating them.

[0017] In one embodiment, the collection step involves capturing the fine bubbles by filtering the processing liquid with a filter provided in the middle of the processing liquid flow path, and guiding the fine bubbles captured by the filter to a branched flow path that branches off from the processing liquid flow path.

[0018] The aforementioned filter typically allows particles that are not attached to fine bubbles to pass through, and differs from a filter designed to capture particles that exist independently.

[0019] In one embodiment, the processing liquid channel includes a return pipe for returning the processing liquid to a processing liquid tank that stores the processing liquid. A portion of the processing liquid, along with the fine bubbles, is led to the branch channel. The method further includes the step of returning the processing liquid led to the branch channel to the processing liquid tank via the return pipe.

[0020] In one embodiment, the process further includes a step of disposing of the treatment liquid in the treatment liquid tank.

[0021] In one embodiment, the waste liquid disposal step involves disposing of the portion of the treatment liquid stored in the treatment liquid tank that is near the liquid surface.

[0022] In one embodiment, the collection step includes separating and collecting the fine bubbles to which the particles are attached from the processing liquid flowing through the return pipe, and guiding them to a waste channel for disposal.

[0023] In one embodiment, the collection step separates the fine bubbles to which the particles are attached from the processing liquid flowing through the processing liquid channel at multiple locations in the processing liquid channel and guides them to multiple branched channels branching off from each of the multiple locations. A portion of the processing liquid is guided into each branched channel along with the fine bubbles. The method further includes the steps of returning the processing liquid guided into at least one of the multiple branched channels to a processing liquid tank that stores the processing liquid, and discarding the processing liquid guided into at least one of the multiple branched channels without returning it to the processing liquid tank.

[0024] In one embodiment, the fine bubbles include microbubbles and ultrafine bubbles.

[0025] One embodiment of this invention provides a substrate processing apparatus that includes a nozzle for supplying a processing liquid to a substrate, a processing liquid channel through which the processing liquid flows, a bubble generator for supplying fine bubbles to the processing liquid flowing through the processing liquid channel, and a particle separator for separating and collecting the fine bubbles from the processing liquid flowing through the processing liquid channel, thereby separating particles attached to the fine bubbles.

[0026] In one embodiment, the particle separator includes a bend in the piping that constitutes the processing liquid flow path, and a branch flow path that branches off from the piping in a direction tangential to the bend.

[0027] In one embodiment, the bent portion includes a spiral tube provided in the piping.

[0028] In one embodiment, the particle separator includes an electrode that applies an electric field (typically a DC electric field) to the processing liquid flowing through the processing liquid channel, and a branch channel into which fine bubbles whose trajectories are altered by the electric field are guided.

[0029] In one embodiment, the particle separator includes a filter provided in the middle of the processing liquid flow path for filtering the processing liquid and capturing the fine bubbles, and a branched flow path to which the fine bubbles captured by the filter are guided.

[0030] The above-mentioned, or further, objectives, features, and effects of the present invention will be made clearer by the following description of embodiments with reference to the accompanying drawings.

[0031] Figure 1 is a schematic plan view illustrating the internal layout of a substrate processing apparatus according to one embodiment of the present invention. Figure 2 is a schematic longitudinal cross-sectional view of the substrate processing apparatus. Figure 3 is a schematic diagram showing an example of the configuration of a processing liquid supply device provided in the substrate processing apparatus. Figures 4A and 4B are schematic cross-sectional views illustrating an example of the configuration of a particle separator. Figure 5 is a block diagram illustrating the electrical configuration of the main part of the substrate processing apparatus. Figure 6 is a process diagram illustrating a particle removal method performed in the substrate processing apparatus. Figure 7 is a diagram illustrating the configuration of a substrate processing apparatus according to another embodiment of the present invention. Figure 8 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention. Figure 9 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention. Figure 10 is a schematic cross-sectional view showing an example of the configuration of a particle separator. Figure 11 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention. Figure 12 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention. Figure 13 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention.

[0032] Hereinafter, embodiments of this invention will be described in detail with reference to the accompanying drawings.

[0033] Figure 1 is a schematic plan view illustrating the internal layout of a substrate processing apparatus 1 according to one embodiment of the present invention. Figure 2 is a schematic longitudinal cross-sectional view of the substrate processing apparatus 1.

[0034] The substrate processing apparatus 1 is a single-wafer type apparatus that processes substrates W, such as silicon wafers, one at a time. In this embodiment, the substrate W is a disc-shaped substrate. The substrate processing apparatus 1 includes a plurality of (four in this embodiment) processing towers 2A to 2D (processing units) that process the substrate W with processing liquids such as chemical solutions and rinsing solutions. The plurality of processing towers 2A to 2D are collectively referred to as processing tower 2. The substrate processing apparatus 1 further includes a processing liquid supply device 3 that supplies processing liquids to the plurality of processing towers 2A to 2D, and fluid units 4A to 4D that are provided corresponding to each processing tower 2A to 2D and house piping for supplying processing liquids to the processing towers 2A to 2D.

[0035] Each processing tower 2A to 2D includes multiple (for example, three) processing units 20 stacked vertically (see Figure 2). Each processing unit 20 is a single-wafer processing unit that processes one substrate W at a time. Multiple processing units 20 have, for example, similar configurations.

[0036] The substrate processing apparatus 1 further includes a load port LP on which a carrier C for accommodating multiple substrates W to be processed by the processing unit 20 is placed, an indexer robot IR and a center robot CR which are transport robots for transporting the substrates W between the load port LP and the processing unit 20, and a control device 7 for controlling the substrate processing apparatus 1.

[0037] The substrate processing apparatus 1 further includes a transport path 5 extending horizontally. The transport path 5 extends linearly from the indexer robot IR to the center robot CR. The indexer robot IR transports the substrate W between the carrier C and the center robot CR. The center robot CR transports the substrate W between the indexer robot IR and the processing unit 20.

[0038] Multiple processing towers 2 are arranged symmetrically on either side of the transport path 5. The multiple processing towers 2 are lined up along the direction in which the transport path 5 extends (extension direction X) on each side of the transport path 5. In this embodiment, two processing towers 2 are arranged on each side of the transport path 5.

[0039] Of the multiple processing towers 2A to 2D, the two processing towers 2 closest to the indexer robot IR are referred to as the first processing tower 2A and the second processing tower 2B. The first processing tower 2A and the second processing tower 2B face each other across the transport path 5. Of the multiple processing towers 2A to 2D, the two processing towers 2 furthest from the indexer robot IR are referred to as the third processing tower 2C and the fourth processing tower 2D. The third processing tower 2C and the fourth processing tower 2D face each other across the transport path 5. The first processing tower 2A and the third processing tower 2C are arranged side by side in the extension direction X. The second processing tower 2B and the fourth processing tower 2D are arranged side by side in the extension direction X. Each processing tower 2A to 2D has a corresponding fluid unit 4A to 4D adjacent to it from the extension direction X.

[0040] The processing liquid supply device 3 includes a processing liquid supply source R. The substrate processing device 1 is located on the opposite side of the indexer robot IR in the extension direction X and includes a cabinet 6 that houses the processing liquid supply source R. The processing liquid supply source R is located inside the cabinet 6 at a position closer to the other processing tower 2D of the processing towers 2C and 2D, which are located on either side of the transport path 5, than to the processing tower 2C of the processing towers 2C and 2D, which are located on either side of the transport path 5.

[0041] Figure 3 is a schematic diagram showing an example of the configuration of a processing liquid supply device 3 provided in the substrate processing apparatus 1.

[0042] The processing liquid supply device 3 includes tower supply pipes 22A to 22D that distribute and supply the processing liquid in the processing liquid tank 21 to a plurality of processing towers 2A to 2D. The processing liquid supply source R includes a processing liquid tank 21 for storing the processing liquid and a common pipe 24 that connects the processing liquid tank 21 to the upstream ends of the plurality of tower supply pipes 22A to 22D.

[0043] In the processing liquid tank 21, a chemical solution (stock solution) of a predetermined concentration is supplied from the chemical solution supply source 10 through the chemical solution supply pipe 11, and DIW (deionized water) is supplied from the DIW supply source 13 through the DIW supply pipe 14. Thereby, the chemical solution (stock solution) is diluted with DIW in the processing liquid tank 21, and a chemical solution of an appropriate concentration suitable for processing the substrate W is prepared. A chemical solution valve 12 is installed in the chemical solution supply pipe 11, and the supply / stop of the chemical solution can be switched by opening and closing it. A DIW valve 15 is installed in the DIW supply pipe 14, and the supply / stop of DIW can be switched by opening and closing it. The chemical solution supply source 10 typically includes a stock solution tank for storing the stock solution. The DIW supply source 13 typically includes a DIW pipe from the utility facilities of the factory where the substrate processing apparatus 1 is arranged.

[0044] At the bottom of the processing liquid tank 21, a drain pipe 17 is connected. A drain valve 18 for opening and closing its flow path is installed in the drain pipe 17. By opening the drain valve 18, the processing liquid in the processing liquid tank 21 can be discharged through the drain pipe 17 and discarded as waste liquid.

[0045] The plurality of tower supply pipes 22A to 22D are branched from the downstream end of the common pipe 24. When collectively referring to the tower supply pipes 22A to 22D, they are called the tower supply pipe 22.

[0046] A pump 30 and a bubble generator 31 are installed in the common pipe 24 in this order from the upstream side. The pump 30 sends out the processing liquid in the common pipe 24 to the downstream side. The bubble generator 31 supplies fine bubbles to the processing liquid flowing through the common pipe 24. Therefore, on the downstream side of the bubble generator 31, fine bubbles are contained in the processing liquid, and the fine bubbles flow along with the flow of the processing liquid. The processing liquid containing these fine bubbles is sent out to the tower supply pipes 22A to 22D.

[0047] The members of the processing liquid supply device 3 related to each of the processing towers 2A to 2D have substantially the same configuration in all of the processing towers 2A to 2D. Therefore, hereinafter, in the processing liquid supply device 3, the members corresponding to the first processing tower 2A will be mainly described. In FIG. 3, the configuration around the first processing tower 2A and the corresponding tower supply pipe 22A is shown, and the illustration of the configurations related to the other processing towers 2B to 2D and the other tower supply pipes 22B to 22D is omitted.

[0048] Each processing unit 20 of the first processing tower 2A is a single wafer type processing unit. The processing unit 20 includes a spin chuck 40 that rotates the substrate W around a vertical rotation axis A1 passing through the central portion of the substrate W while holding a single substrate W in a horizontal posture, a first nozzle 41 and a second nozzle 42 that supply a processing liquid to the substrate W, a cup 43 that surrounds the spin chuck 40, and a processing chamber 44 that houses the spin chuck 40, the first nozzle 41, the second nozzle 42, and the cup 43 and partitions a processing space for processing the substrate W.

[0049] An entrance and exit (not shown) for carrying the substrate W into and out of the processing chamber 44 is formed in the processing chamber 44. The processing chamber 44 is provided with a shutter unit (not shown) that opens and closes the entrance and exit.

[0050] Although not shown in the drawing, the spin chuck 40 typically includes a disk-shaped spin base, a rotation shaft coupled to the center of the lower surface of the spin base, and an electric motor that applies a rotational force to the rotation shaft.

[0051] In this embodiment, the first nozzle 41 and the second nozzle 42 are arranged to discharge the processing liquid toward the rotation center of the upper surface of the substrate W. These may be fixed nozzles or movable nozzles. The first nozzle 41 is supplied with processing liquid, such as a chemical solution, stored in the processing liquid tank 21 of the processing liquid supply source R, via the tower supply piping 22A and the unit supply piping 23, which branches from the tower supply piping 22A to each processing unit 20 in the tower. The second nozzle 42 is supplied with processing liquid, such as a rinse liquid, via piping 51 from a rinse liquid supply system 50 having a different supply source than the processing liquid supply source R. A valve 52 is interposed in piping 51 to switch whether or not processing liquid is supplied to the second nozzle 42.

[0052] A chemical solution is, for example, hydrofluoric acid (hydrogen fluoride solution: HF). The chemical solution is not limited to hydrofluoric acid, but may also contain at least one of the following: sulfuric acid, acetic acid, nitric acid, hydrochloric acid, buffered hydrofluoric acid (BHF), dilute hydrofluoric acid (DHF), ammonia water, hydrogen peroxide solution, organic acids (e.g., citric acid, oxalic acid, etc.), organic alkalis (e.g., TMAH: tetramethylammonium hydroxide, etc.), surfactants, and corrosion inhibitors. Examples of chemical solutions that are mixtures of these include SPM (sulfuric acid-hydrogen peroxide mixture), SC1 (ammonia-hydrogen peroxide mixture), and SC2 (hydrochloric acid-hydrogen peroxide mixture). The chemical solution typically contains water and is therefore an aqueous solution.

[0053] The rinse solution is, for example, deionized water (DIW). The rinse solution is not limited to DIW; it may also be carbonated water, electrolyzed ionized water, ozonated water, hydrochloric acid water at a diluted concentration (for example, around 10-100 ppm), or reduced water (hydrogen water). The rinse solution typically contains water.

[0054] The unit supply piping 23 branches off from the tower supply piping 22A and supplies processing liquid to the first nozzle 41 of the corresponding processing unit 20.

[0055] Each of the multiple unit supply pipes 23 is fitted with a supply valve 36, a supply flow rate adjustment valve 37, and a supply flow meter 38, in that order from upstream to upstream, upstream of the first nozzle 41. Each supply valve 36 switches the supply of processing liquid to the first nozzle 41. Each supply flow rate adjustment valve 37 adjusts the flow rate of processing liquid flowing through the unit supply pipe 23 toward the first nozzle 41. Each supply flow meter 38 detects the flow rate of processing liquid flowing through the unit supply pipe 23 toward the first nozzle 41. The supply valve 36 is, for example, an on / off valve. The supply flow rate adjustment valve 37 is, for example, a motor needle valve.

[0056] The tower supply piping 22A includes an upstream piping section 60 housed in the cabinet 6, an ascending piping section 61 and a descending piping section 62 housed in the fluid unit 4A, and a relay piping section 63 connecting the upstream piping section 60 and the ascending piping section 61, and extending between the cabinet 6 and the fluid unit 4A. The ascending piping section 61 and the descending piping section 62 are each composed of substantially straight pipes arranged in the vertical direction. The processed liquid flows upward through the ascending piping section 61 and downward through the descending piping section 62. Multiple unit supply pipes 23 branch off from the descending piping section 62.

[0057] The upward piping section 61 and the downward piping section 62 are connected by a supply pipe bend 64 (curved section) which is composed of an upwardly convex curved (inverted U-shaped) pipe section. Therefore, the processing liquid flowing upward through the upward piping section 61 is bent downward in the supply pipe bend 64, and flows downward through the downward piping section 62. A branch pipe 65 is connected to the supply pipe bend 64, forming a branched flow path that branches tangentially to the flow path. Therefore, a portion of the processing liquid passing through the supply pipe bend 64 is guided to the branch pipe 65. The branch pipe 65 is connected to a return pipe 66. The return pipe 66 is a pipe that returns the processing liquid to the processing liquid tank 21.

[0058] The unit supply piping 23 has a horizontal section 23a that extends horizontally in a straight line, a descending section 23b that extends downward toward the first nozzle 41, and a nozzle-front bend section 23c that connects the horizontal section 23a and the descending section 23b. The nozzle-front bend section 23c is provided inside the processing chamber 44. The nozzle-front bend section 23c is the bend immediately before the first nozzle 41, and there is no bend in the flow path between the nozzle-front bend section 23c and the first nozzle 41. The nozzle-front bend section 23c changes the flow direction of the processing liquid by approximately 90 degrees. A branch pipe 25 is provided that forms a branch flow path branching off from the unit supply piping 23 in the tangential direction (horizontal direction in this example) of the flow path of the nozzle-front bend section 23c. The branch pipe 25 is connected to the return pipe 66. A branch flow meter 26 is interposed in the branch pipe 25. The branch flow meter 26 measures the flow rate of the treatment liquid flowing through the branch pipe 25. The discharge flow rate value discharged from the first nozzle 41 can be determined by the difference between the supply flow rate value measured by the supply flow meter 38 and the branch flow rate value measured by the branch flow meter 26.

[0059] The processing liquid flowing through the unit supply piping 23 is guided to the first nozzle 41 through the horizontal section 23a, the nozzle bend section 23c, and the descending section 23b, and is discharged from the discharge port of the first nozzle 41 toward the surface of the substrate W. A portion of the processing liquid flowing through the horizontal section 23a is guided from the nozzle bend section 23c to the branch piping 25, and further guided to the return piping 66.

[0060] The processing liquid tank 21, common piping 24, tower supply piping 22, unit supply piping 23, and return piping 66 form a processing liquid flow path through which the processing liquid flows. The common piping 24, tower supply piping 22, and unit supply piping 23 constitute a supply piping that supplies the processing liquid from the processing liquid tank 21 to the substrate W.

[0061] The supply pipe bend 64 and the branch pipe 65 branching off from it constitute a first particle separator 71. The nozzle bend 23c and the branch pipe 25 branching off from it constitute a second particle separator 72. The first particle separator 71 and the second particle separator 72 separate and collect fine bubbles in the processing liquid, thereby removing particles attached to the fine bubbles from the processing liquid.

[0062] The particles to be removed include particles mixed in the chemical solution supplied from the chemical solution supply source 10. Furthermore, the particles to be removed include particles mixed in the DIW supplied from the DIW supply source 13. Additionally, the particles to be removed include particles originating from the flow path components that constitute the processing liquid flow path. Flow path components are components that come into contact with the processing liquid, such as pipes, valves, and flow meters. At least the portion of the flow path components that comes into contact with the processing liquid is typically made of fluororesin. From flow path components made of fluororesin, resin and additives such as plasticizers in the resin may leach out and be observed as particles. Furthermore, flow path components made of fluororesin trap or release foreign matter in the processing liquid. Therefore, flow path components are one of the particle sources.

[0063] Most particles observed on the surface of substrates (especially semiconductor wafers) are organic, and therefore, it is assumed that most particles present in the processing solution are organic. Since organic particles are hydrophobic, they adhere more easily to bubbles than water.

[0064] The bubble generator 31 is a device that generates fine bubbles, and for example, a fine bubble generator manufactured by Nippon Sangyo Co., Ltd. can be used.

[0065] Fine bubbles are defined as "fine bubbles" in the International Organization for Standardization (ISO) 20480-1 and the Japanese Industrial Standard (JIS) B 8741-1. Fine bubbles include ultrafine bubbles and microbubbles, but do not include millibubbles or sub-millibubbles. Ultrafine bubbles are bubbles with a diameter of several tens of nanometers to 1 μm. Microbubbles are bubbles with a diameter of 1 μm to 100 μm. Millibubbles / sub-millibubbles are bubbles with a diameter greater than 100 μm.

[0066] Ultrafine bubbles present in water are invisible to the naked eye, and water containing ultrafine bubbles is colorless and transparent. Ultrafine bubbles remain in water for several weeks to several months, and their viscous force is greater than their buoyancy, causing them to persist while undergoing Brownian motion (microscopic movement) in the water.

[0067] Microbubbles present in water are visible to the naked eye, and water containing microbubbles appears cloudy. Microbubbles remain in water for several minutes to tens of minutes. Microbubbles in water rise very slowly (for example, a bubble with a diameter of 10 μm rises at a speed of about 3 mm / minute). As microbubbles slowly rise, they disappear due to the dissolution of gas into the water. If gas remains undissolved, they shrink in size and become ultrafine bubbles. In addition, multiple microbubbles may combine to form millibubbles / sub-millibubbles.

[0068] Fine bubbles in liquids (ultrafine bubbles and microbubbles) behave substantially the same as the surrounding liquid and exhibit different behavior from millibubbles / submillibubbles. Millibubbles / submillibubbles rise very quickly in water (a 1 mm diameter bubble rises at a speed of approximately 5 m / min to 6 m / min) and do not behave like the surrounding liquid.

[0069] Fine bubbles are electrically negatively charged. They also have the ability to physically attract particles, similar to ordinary bubbles. Furthermore, the energy released locally when a bubble collapses (e.g., light emission, heat generation, shock waves) promotes the detachment of adhering substances within the treatment liquid flow path. This energy is greater in ultrafine bubbles than in microbubbles.

[0070] From a cleaning perspective, microbubbles clean by adsorbing dirt and lifting it to the surface. Ultrafine bubbles also adsorb and remove dirt, but they do not float in water, so they require assistance from liquid flow to clean. Because ultrafine bubbles are tiny bubbles of 1 μm or less, they have the effect of lowering the surface tension of the liquid, which allows them to penetrate into the gaps of dirt and lift and remove it.

[0071] By using both ultrafine bubbles and microbubbles, the ultrafine bubbles can detach dirt, while the microbubbles can lift the dirt to the surface.

[0072] In this embodiment, the bubble generator 31 generates fine bubbles, including both ultrafine bubbles and microbubbles, and disperses them in the processing liquid. Any method may be used for generating the fine bubbles, such as a high-speed swirling liquid flow method or a Venturi method. A gas introduction line 32 is connected to the bubble generator 31, through which an inert gas such as nitrogen gas or air is introduced. A gas valve 33 is interposed in the gas introduction line 32. The gas valve 33 may be an on / off valve or a valve with adjustable opening.

[0073] Although a detailed illustration is omitted in Figure 3, the rinse solution supply system 50 is substantially configured in the same way as the aforementioned configuration for supplying chemical solutions (chemical solution supply system), except that it does not use chemical solutions, and is equipped with a mechanism for removing particles from the rinse solution, which is a type of processing solution.

[0074] Figure 4A is an enlarged, illustrative cross-sectional view showing the configuration of the first particle separator 71, and Figure 4B is an enlarged, illustrative cross-sectional view showing the configuration of the second particle separator 72.

[0075] When particles P are attached to fine bubbles F, they behave as a single unit of particles in the treatment liquid. The particles formed by the attachment of particles P to fine bubbles F have a density greater than that of water, and therefore greater than that of the treatment liquid. As a result, when such particles pass through a curved channel together with the laminar flowing treatment liquid, they become concentrated on the outside of the curved channel (the side farther from the center of curvature) due to the large centrifugal force (inertial force).

[0076] As shown in Figure 4A, the processing liquid flowing upward through the ascending piping section 61 of the tower supply piping 22 enters the supply piping bend 64 of the first particle separator 71 in a laminar flow state, where its flow direction is changed by approximately 180 degrees before flowing into the descending piping section 62. At the supply piping bend 64, particles with particles P attached to the fine bubbles F are subjected to a stronger centrifugal force than the processing liquid, so the distribution density in the outer region of the curved flow path of the supply piping bend 64 becomes greater than the distribution density in the central and inner regions.

[0077] The branch pipe 65 is connected to the outside of the supply pipe bend 64 and branches off from the tower supply pipe 22 so as to extend tangentially to the curved flow path of the supply pipe bend 64. As a result, many of the fine bubbles F to which particles P are attached are guided to the branch pipe 65 and separated from the main flow of the processing liquid heading toward the descending pipe section 62 and collected.

[0078] The supply pipe bend 64 forms an upwardly convex curved flow path, and by utilizing the property of microbubbles floating in the processing liquid, it can collect microbubbles and guide them to the branch pipe 65. Ultrafine bubbles to which particles are attached are guided to the outside (upper side) of the curved flow path of the supply pipe bend 64 by centrifugal force and the buoyancy effect of the microbubbles. As a result, particles P in the processing liquid can be efficiently separated and collected in the branch pipe 65.

[0079] When the supply valve 36 is opened and processing liquid is supplied to the substrate W, the processing liquid flows from the descending piping section 62 into the unit supply piping 23. As shown in Figure 4B, this processing liquid flows in a laminar state through the horizontal section 23a of the unit supply piping 23, enters the nozzle bend section 23c, changes its flow direction by approximately 90 degrees, flows into the descending section 23b, and is discharged downward from the first nozzle 41. At the nozzle bend section 23c, the inertial force (centrifugal force) acting on particles with particles P attached to them is greater than the inertial force (centrifugal force) acting on the same volume of processing liquid. Therefore, most of the fine bubbles with attached particles do not enter the nozzle bend section 23c, but flow into the branch piping 25 which extends horizontally, tangential to the nozzle bend section 23c. As a result, most of the fine bubbles F with attached particles P are separated from the main flow of processing liquid heading towards the first nozzle 41 and collected.

[0080] In this way, particles P in the processing liquid are attached to fine bubbles F, and the fine bubbles F are separated from the processing liquid and collected, allowing the processing liquid from which particles P have been removed to be supplied to the substrate W from the first nozzle 41.

[0081] Figure 5 is a block diagram illustrating the electrical configuration of the main parts of the substrate processing apparatus 1.

[0082] The control device 7 is equipped with a microcomputer and controls the control target provided in the substrate processing device 1 according to a predetermined program. More specifically, the control device 7 includes a processor (CPU) 7A and a memory 7B in which a program is stored, and the processor 7A is configured to execute various controls for substrate processing by executing the program.

[0083] The control device 7 controls the operation of the indexer robot IR, the center robot CR, the chemical solution valve 12, the DIW valve 15, the drain valve 18, the pump 30, the gas valve 33, the supply valve 36, the supply flow rate adjustment valve 37, the spin chuck 40, and the valve 52. The control device 7 also receives flow rate measurement signals from the supply flow meter 38 and the branch flow meter 26. Based on the flow rate values ​​measured by the supply flow meter 38 and the branch flow meter 26, the control device 7 controls the opening of the supply flow rate adjustment valve 37, thereby enabling the discharge of the processed liquid from the first nozzle 41 at a target flow rate.

[0084] The control device 7 may control the generation of fine bubbles by the bubble generator 31. For example, the control device 7 may control the generation of fine bubbles by the bubble generator 31 by controlling the opening and closing or the degree of opening of a gas valve 33 interposed in the gas introduction line 32 to the bubble generator 31.

[0085] Figure 6 is a process diagram illustrating a particle removal method performed in the substrate processing apparatus 1. The multiple steps shown in Figure 6 are not necessarily performed in the order shown in Figure 6, but are typically performed simultaneously. In this embodiment, the substrate processing apparatus 1 removes particles from the processing liquid and supplies the processed liquid from which the particles have been removed to the substrate W to perform processing on the substrate W.

[0086] The particle removal method includes step S1, which involves circulating the processing liquid through the processing liquid flow path. Specifically, step S1 is achieved by operating the pump 30 using the control device 7. The pump 30 pumps the processing liquid from the processing liquid tank 21 and circulates it through the common piping 24, the tower supply piping 22, and the unit supply piping 23. A portion of the processing liquid also circulates through the branch piping 65, 25 and the return piping 66.

[0087] The particle removal method further includes step S2 of supplying fine bubbles to the processing liquid flowing through the processing liquid channel. Specifically, fine bubbles are supplied to the processing liquid by supplying the processing liquid from the common piping 24 and an inert gas from the gas introduction line 32 to a bubble generator 31 interposed in the common piping 24. In this embodiment, as described above, the fine bubbles include microbubbles and ultrafine bubbles.

[0088] The particle removal method further includes step S3, which involves attaching particles in the processing liquid flowing through the processing liquid channel to fine bubbles. As mentioned above, particles are mostly organic matter and therefore hydrophobic, and are adsorbed by bubbles such as fine bubbles. This allows particles present in the processing liquid to be attached to other particles also present in the processing liquid.

[0089] The particle removal method further includes step S4 of separating and collecting fine bubbles to which particles are attached from the processing liquid flowing through the processing liquid passage. In this embodiment, this step is achieved by the action of a first particle separator 71 provided in the tower supply pipe 22 which constitutes the supply piping, and a second particle separator 72 provided in the unit supply pipe 23 which also constitutes the supply piping. As particles are separated and collected in the supply piping, the processing liquid that has undergone particle separation and removal treatment is discharged from the first nozzle 41. This makes it possible to supply a clean processing liquid with a low particle count to the substrate W.

[0090] The particle removal method also includes step S5, which involves returning the processed liquid, which has been guided to branch pipes 65 and 25 (branched flow paths) in the first particle separator 71 and the second particle separator 72, to the processed liquid tank 21 via a return pipe 66. The processed liquid containing many fine bubbles to which particles are attached is guided to the branch pipes 65 and 25, and this processed liquid is returned to the processed liquid tank 21.

[0091] The particle removal method also includes a step S6 of disposing of the treatment liquid in the treatment liquid tank 21. The control device 7 controls the drain valve 18 to a closed state when storing the treatment liquid in the treatment liquid tank 21. On the other hand, the control device 7 opens the drain valve 18 when disposing of the treatment liquid in the treatment liquid tank 21. As a result, the treatment liquid in the treatment liquid tank 21 is discharged through the drain pipe 17 and disposed of. After disposal, the control device 7 closes the drain valve 18, opens the chemical solution valve 12 and the DIW valve 15, supplies the chemical solution and DIW to the treatment liquid tank 21, and prepares new treatment liquid in the treatment liquid tank 21. In this way, the treatment liquid is replaced.

[0092] It is preferable to replace the processing solution periodically. Specifically, the control device 7 determines when it is time to replace the processing solution (the lifespan of the processing solution) based on the usage time of the processing solution (for example, the time elapsed since the preparation of the processing solution) and the amount of substrates processed (for example, the number of substrates W processed or the number of lots). When it is time to replace the processing solution, the control device 7 performs the replacement of the processing solution when the substrates W are not being processed. By performing the replacement of the processing solution at an appropriate time, it is possible to avoid the excessive accumulation of particles in the processing solution.

[0093] Thus, the particle removal method of this embodiment removes particles from the processing liquid by supplying fine bubbles into the processing liquid, allowing particles in the processing liquid to adhere to the fine bubbles, and then separating and collecting the fine bubbles to which the particles have adhered. Since fine bubbles remain in the processing liquid for a long time, they can adhere to a larger number of particles in the processing liquid than ordinary bubbles such as millibubbles / sub-millibubbles, thereby efficiently removing particles from the processing liquid. In addition, the energy released when the fine bubbles disappear can promote the detachment of foreign matter attached to the flow channel forming member, and ultrafine bubbles in particular have the effect of penetrating into gaps in dirt and lifting and removing the dirt. Therefore, foreign matter in the processing liquid flow channel can be removed more effectively than when ordinary bubbles such as millibubbles / sub-millibubbles are used. As a result, a highly clean processing liquid can be supplied to the substrate W, thereby improving the quality of substrate processing.

[0094] In this embodiment, the fine bubbles include both ultrafine bubbles and millibubbles. This allows the millibubbles to float up foreign matter that has been removed by the action of the ultrafine bubbles. Therefore, the first particle separator 71, which has a supply pipe bend 64 that forms an upwardly convex curved flow path, can efficiently separate and remove foreign matter (particles).

[0095] Furthermore, since particles in the processing liquid can be removed by the first and second particle separators 71 and 72, a filter for capturing particles is not required. As a result, filter replacement is unnecessary, reducing the time the substrate processing apparatus 1 must be stopped for maintenance and increasing productivity. In addition, since there is no need to provide a circulation path for particle removal that passes through a particle capture filter, for example, within the cabinet 6, the piping configuration of the processing liquid supply device 3 can be simplified. Accordingly, the number of stagnant areas in the processing liquid can be reduced, thereby reducing the elution of foreign matter from the flow path components and the adhesion and release of foreign matter from the surface of the flow path components. Therefore, large fluctuations in the amount of particles in the processing liquid can be suppressed when the flow state of the processing liquid in the processing liquid flow path changes (especially when flow starts from a stopped state).

[0096] Furthermore, since the behavior of fine bubbles in the processing liquid differs from that of ordinary bubbles such as millibubbles / sub-millibubbles, the apparatus using swirling flow described in Patent Document 1 is not suitable for separating fine bubbles from the processing liquid.

[0097] Figure 7 is a diagram illustrating the configuration of a substrate processing apparatus according to another embodiment of the present invention, and shows another example of the configuration of the processing liquid supply device 3. In Figure 7, the same reference numerals are used for the corresponding parts shown in Figure 3, and redundant explanations are omitted where possible.

[0098] In this embodiment, the first particle separator 71 in the previously described embodiment is not provided. Instead, a third particle separator 73 is provided, which includes a spiral tube 80 and at least one (two in this embodiment) branch pipes 81 branching from the spiral tube 80.

[0099] The spiral tube 80 is a pipe having a spiral-shaped flow path. The spiral tube 80 is interposed in the tower supply pipe 22 and constitutes a part of the supply pipe. The spiral tube 80 is an example of a supply pipe bend provided in the supply pipe.

[0100] A branch pipe 81 is connected to the spiral tube 80 so as to branch tangentially from the spiral flow path of the spiral tube 80. In this embodiment, the spiral tube 80 has a helical axis 80a, which is the central axis of the spiral shape, oriented laterally (more specifically, horizontally). Therefore, the spiral tube 80 has a plurality of upwardly convex curved portions 80b located at intervals along the helical axis 80a. One end of the branch pipe 81 is connected to one of these upwardly convex curved portions 80b along its tangential direction. The other end of the branch pipe 81 is connected to the return pipe 66.

[0101] The rest of the configuration and operation are the same as in the embodiment shown in Figure 3.

[0102] This configuration also achieves the same operation and effects as the embodiment in Figure 3, and allows the particle removal method shown in Figure 6 to be implemented. In addition, the spiral tube 80 provides numerous bends in the piping, allowing particles to be separated at multiple locations as needed. This makes it possible to separate particles in the processing liquid even more efficiently.

[0103] Figure 8 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention, and shows yet another example of the configuration of the processing liquid supply device 3. In Figure 8, the same reference numerals are used for the corresponding parts of the components shown in Figure 3, and redundant explanations are omitted where possible.

[0104] In this embodiment, the first particle separator 71 and the second particle separator 72 are not provided. Instead, a fourth particle separator 74 and a fifth particle separator 75 are provided, which apply an electric field (particularly a DC electric field) to the processing liquid flowing through the processing liquid channel to change the trajectory of fine bubbles in the processing liquid. In the configuration example shown in Figure 8, the fourth particle separator 74 is located in the tower supply piping 22, and the fifth particle separator 75 is located in each unit supply piping 23.

[0105] The fourth particle separator 74 includes a first electrode E1 located in the tower supply pipe 22, which is part of the supply piping; a branch pipe 83 that forms a branched channel branching off from the tower supply pipe 22; and a second electrode E2 located in the branch pipe 83.

[0106] The first electrode E1 is positioned near the connection point of the branch pipe 83 to the tower supply pipe 22, i.e., near the branch position 83a. The first electrode E1 is an electrode with the same polarity as the charge polarity (negative) of the fine bubbles, and in this embodiment, it is the negative electrode. Accordingly, the second electrode E2 is an electrode with the opposite polarity to the charge polarity of the fine bubbles, and in this embodiment, it is the positive electrode. Therefore, the first electrode E1 exerts a repulsive force (Coulomb force) on the fine bubbles, and the second electrode E2 exerts an attractive force (Coulomb force) on the fine bubbles. As a result, the processing liquid flowing through the tower supply pipe 22 is subjected to a Coulomb force directed toward the branch pipe 83 near the first electrode E1, its trajectory is altered, and it is guided toward the branch pipe 83. The branch pipe 83 is connected to the return pipe 66.

[0107] Similarly, the fifth particle separator 75 includes a first electrode E11 located in the unit supply pipe 23, which is part of the supply pipe; a branch pipe 84 that forms a branch channel branching off from the unit supply pipe 23; and a second electrode E12 located in the branch pipe 84. The first electrode E11 is located near the connection point of the branch pipe 84 to the unit supply pipe 23, i.e., the branching point 84a.

[0108] The first electrode E11 is an electrode with the same polarity as the charge polarity (negative) of the fine bubbles, and in this embodiment, it is the negative electrode. Accordingly, the second electrode E12 is an electrode with the opposite polarity to the charge polarity of the fine bubbles, and in this embodiment, it is the positive electrode. Therefore, the first electrode E11 exerts a repulsive force (Coulomb force) on the fine bubbles, and the second electrode E12 exerts an attractive force (Coulomb force) on the fine bubbles. As a result, the processing liquid flowing through the unit supply pipe 23 is subjected to a Coulomb force directed toward the branch pipe 84 near the first electrode E11, its trajectory is altered, and it is guided toward the branch pipe 84. The branch pipe 84 is connected to the return pipe 66. In the example of Figure 8, the second electrode E12 is located at the connection position 84b with the return pipe 66, and can also be said to be located on the return pipe 66.

[0109] Thus, in this embodiment, the fourth particle separator 74 separates and collects fine bubbles to which particles are attached from the processing liquid flowing through the tower supply pipe 22. Then, in each of the multiple unit supply pipes 23 branching off from the tower supply pipe 22, fine bubbles to which particles are attached are separated and collected from the processing liquid flowing through the unit supply pipe 23 just before the first nozzle 41. As a result, a clean processing liquid with fewer particles can be supplied to the substrate W from the first nozzle 41.

[0110] The particle removal method shown in Figure 6 can also be performed with the configuration of this embodiment. In this embodiment, the collection step S4 involves applying an electric field (DC electric field) to the processing liquid flowing through the processing liquid channel to change the trajectory of the fine bubbles in the processing liquid, and guiding the fine bubbles to branch pipes 83 and 84 that form branch channels branching off from the processing liquid channel for separation.

[0111] The second electrodes E2 and E12, which are located near the branch pipes 83 and 84, may be omitted (or placed in a different location), and the trajectory of the fine bubbles in the processing liquid may be changed and guided to the branch pipes 83 and 84 solely by the repulsive force (Coulomb force) of the first electrodes E1 and E11.

[0112] Figure 9 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention, and shows yet another example of the configuration of the processing liquid supply device 3. In Figure 9, the same reference numerals are used for the corresponding parts shown in Figure 3, and redundant explanations are omitted where possible.

[0113] In this embodiment, the first particle separator 71 and the second particle separator 72 are not provided. Instead, a sixth particle separator 76 is provided, which has a filter 85 that filters the processing liquid flowing through the processing liquid channel to capture fine bubbles in the processing liquid, and a branch pipe 86 that forms a branch channel to which the fine bubbles captured by the filter 85 are led.

[0114] The sixth particle separator 76 is interposed in each unit supply pipe 23 and captures fine bubbles in the supply pipe at a position close to the first nozzle 41.

[0115] As shown in the enlarged schematic cross-sectional view in Figure 10, the filter 85 has a filtration membrane 91 that allows the processing liquid to pass through and a housing 92 that supports the filtration membrane 91 inside. The housing 92 has an inlet 93 through which the processing liquid is introduced from the upstream unit supply pipe 23 and an outlet 94 through which the processing liquid flows out to the downstream unit supply pipe 23. The space inside the housing 92 has a capture chamber 92A, which is an upstream chamber that communicates with the inlet 93, and a passage chamber 92B, which is a downstream chamber through which the processing liquid that has passed through the filtration membrane 91 is guided, and the passage chamber 92B communicates with the outlet 94.

[0116] The filtration membrane 91 has numerous pores with a predetermined pore size to prevent the passage of fine bubbles F. As a result, the fine bubbles F in the processed liquid are blocked by the filtration membrane 91 and captured in the capture chamber 92A. The processed liquid then passes through the filtration membrane 91 to the passage chamber 92B and is guided from the outlet 94 to the downstream unit supply piping 23. The pore size of the filtration membrane 91 is larger than the size of the particles P and smaller than the size of the fine bubbles F. Therefore, it has a larger pore size than a filter that captures particles P, and there is no problem of clogging due to the capture of particles P.

[0117] One end of the branch pipe 86 is connected to the capture chamber 92A. The other end of the branch pipe 86 is connected to the return pipe 66. A portion of the processing liquid flows from the capture chamber 92A to the branch pipe 86, and this flow of processing liquid guides the fine bubbles F captured in the capture chamber 92A to the branch pipe 86. As a result, the fine bubbles F to which particles P have attached are separated from the processing liquid and collected in the branch pipe 86. This allows a clean processing liquid with fewer particles P to be supplied to the substrate W from the first nozzle 41.

[0118] The particle removal method shown in Figure 6 can also be performed with the configuration of this embodiment. In this embodiment, the collection step S4 involves capturing fine bubbles by filtering the processing liquid with a filter 85 provided in the middle of the processing liquid flow path, and guiding the fine bubbles captured by the filter 85 to a branch pipe 86 that forms a branch flow path branching off from the processing liquid flow path.

[0119] The filter 85 may also be placed in the tower supply piping 22 to capture fine bubbles before it branches into multiple unit supply piping 23. In this case, the number of filters 85 can be reduced to simplify the configuration and lower costs. However, in order to capture foreign matter flowing out from the flow path components and supply the cleanest possible processing liquid to the substrate W, it is preferable to place the filter 85 as close as possible to the discharge port of the first nozzle 41.

[0120] Figure 11 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention, and shows yet another example of the configuration of the processing liquid supply device 3. In Figure 11, the same reference numerals are used for the corresponding parts shown in Figure 7, and redundant explanations are omitted where possible.

[0121] In this embodiment, a seventh particle separator 77 is located in a return pipe 66, which is an example of a processing liquid flow path. In this example, the return pipe 66 has a horizontal section 66a that extends horizontally and a descending section 66b that descends toward the processing liquid tank 21, and an arc-shaped bend 66c is formed in the horizontal section 66a and the descending section 66b. A branch pipe 88 is connected to the bend 66c, forming a branch flow path that extends tangentially to the curved flow path. The bend 66c and the branch pipe 88 constitute the seventh particle separator 77.

[0122] The seventh particle separator 77 separates and collects fine bubbles from the processing liquid flowing through the return pipe 66, thereby removing particles attached to the fine bubbles. The operation of separating fine bubbles from the processing liquid is the same as that of the first and second particle separators 71 and 72, as described with reference to Figures 4A and 4B, and utilizes the centrifugal force (inertial force) acting on the fine bubbles to which particles are attached.

[0123] A small amount of processed liquid introduced into the branch pipe 88 along with the fine bubbles is discarded. For example, the branch pipe 88 may be connected to the drain pipe 17 downstream of the drain valve 18, and the small amount of processed liquid introduced into the branch pipe 88 may be discarded through the drain pipe 17. A flow rate adjustment valve 89 may be interposed in the branch pipe 88. By appropriately setting the opening degree of the flow rate adjustment valve 89, the flow rate of the processed liquid discarded through the branch pipe 88 can be limited, thereby preventing the discarding of a large amount of processed liquid. The flow rate adjustment valve 89 may be a manual valve, or it may be a valve whose opening degree can be controlled by the control device 7 (for example, a motor needle valve).

[0124] With the configuration of this embodiment, the same operation and effects as the embodiment in Figure 7 can be achieved, and the particle removal method shown in Figure 6 can be executed. In this case, the collection step S4 includes separating and collecting fine bubbles to which particles have adhered from the processing liquid flowing through the return pipe 66 using the seventh particle separator 77, and guiding them to the branch pipe 88 and the drain pipe 17 that constitute the waste flow path for disposal.

[0125] Furthermore, when the particle removal method is performed using the configuration of this embodiment, the collection step S4 separates the fine bubbles to which particles have adhered from the processing liquid flowing through the processing liquid channel at multiple positions in the processing liquid channel and guides them to branch pipes 25, 81, and 88 which constitute multiple branch channels branching off from each of the multiple positions. A portion of the processing liquid is guided into each branch pipe 25, 81, and 88 along with the fine bubbles. The return step S4 returns the processing liquid guided into at least one of the multiple branch pipes 25, 81, and 88 to the processing liquid tank 21. In addition, the disposal step S6 disposes of the processing liquid guided into at least one of the multiple branch pipes 25, 81, and 88 before returning it to the processing liquid tank 21.

[0126] The configuration of this embodiment can be applied to the embodiment of Figure 3, and a seventh particle separator 77 may be provided in the return piping 66 at a position indicated by the dashed line in Figure 3, for example. In the embodiments of Figures 8 and 9, a seventh particle separator 77 can also be provided in the return piping 66 at a position indicated by the dashed line in each figure, for example.

[0127] As for the configuration of the seventh particle separator 77, instead of the configuration that utilizes the bend in the piping shown in Figure 11, a configuration using a spiral tube similar to that of the third particle separator 73 may be applied, or a configuration that utilizes an electric field similar to that of the fourth particle separator 74 (see Figure 8) may be applied, or a configuration that utilizes a filter similar to that of the sixth particle separator 76 (see Figure 10) may be applied.

[0128] Figure 12 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention, and shows yet another example of the configuration of the processing liquid supply device 3. In Figure 12, the same reference numerals are used for the corresponding parts shown in Figure 7, and redundant explanations are omitted where possible.

[0129] In this embodiment, an overflow drain pipe 97 is connected to the processing liquid tank 21. A drain valve 98 is interposed in the overflow drain pipe 97. In addition, an on / off valve 27 is interposed in the common pipe 24 downstream of the pump 30. With this configuration, the portion of the processing liquid stored in the processing liquid tank 21 near the liquid surface can be guided to the overflow drain pipe 97 and drained.

[0130] Specifically, the control device 7 closes the on / off valve 27, opens the drain valve 98, and further opens the chemical valve 12 and the DIW valve 15. This stops the outflow of the treatment liquid from the treatment liquid tank 21, while new liquid is supplied from the chemical supply pipe 11 and the DIW supply pipe 14. As a result, the liquid level in the treatment liquid tank 21 rises, and when the liquid level reaches the inlet of the overflow drain pipe 97, the portion of the treatment liquid stored in the treatment liquid tank 21 near the liquid surface can be drained through the overflow drain pipe 97.

[0131] Since the microbubbles contained in the fine bubbles float in the processing liquid, the ultrafine bubbles rise along with the rising flow of the microbubbles. In addition, multiple microbubbles may combine with each other to form millibubbles / submillibubbles, which also form an upward flow in the processing liquid. Therefore, the fine bubbles to which particles are attached gather near the liquid surface of the processing liquid stored in the processing liquid tank 21 and can be removed from the processing liquid supply passage through the overflow drain pipe 97 along with a small amount of processing liquid.

[0132] When the particle removal method shown in Figure 6 is performed according to this embodiment, the waste liquid step S6 includes the step of disposing of the portion of the processing liquid stored in the processing liquid tank 21 near the liquid surface.

[0133] The configuration of this embodiment can also be combined with the configurations of the embodiments shown in Figures 3, 8, 9, and 11.

[0134] Figure 13 is a diagram illustrating the configuration of a substrate processing apparatus according to yet another embodiment of the present invention, and shows yet another example of the configuration of the processing liquid supply device 3. In Figure 11, the same reference numerals are used for the corresponding parts shown in Figure 7, and redundant explanations are omitted where possible.

[0135] In this embodiment, the return pipe 66 is omitted. The small amount of processing liquid that is introduced along with the fine bubbles into the branch pipes 25 and 81 that form the branched flow path is discarded. If the pump 30 is operated only when the supply valve 36 is opened, the processing liquid in the tower supply pipe 22 and unit supply pipe 23 does not flow during the period when processing liquid is not being supplied to the substrate W. Therefore, the amount of processing liquid introduced into the branch pipes 25 and 81 and discarded is not very large.

[0136] The particle removal method shown in Figure 6 can also be implemented by this embodiment. However, the return step S5 is not performed. Also, since the processing liquid containing fine bubbles with particles attached is not returned to the processing liquid tank 21, it is not necessarily required to replace / dispose of the processing liquid stored in the processing liquid tank 21. Therefore, the disposal step S6 may be omitted.

[0137] The configuration of this embodiment can also be applied to the configurations of the embodiments shown in Figures 3, 8, 9, and 11.

[0138] While embodiments of this invention have been described above, this invention can also be implemented in other forms.

[0139] For example, in the embodiment described above, the bubble generator 31 is located in the common piping 24, but the bubble generator may be located in another location. For example, bubble generators may be located in the chemical supply piping 11 and the DIW supply piping 14, respectively, and the chemical solution containing fine bubbles and the DIW containing fine bubbles may be supplied to the processing liquid tank 21 to dilute the chemical solution to an appropriate concentration and prepare a processing liquid containing fine bubbles within the processing liquid tank 21.

[0140] Furthermore, although the above-described embodiment showed an example using a bubble generator 31 that generates both microbubbles and ultrafine bubbles, two bubble generators that generate microbubbles and ultrafine bubbles respectively may also be used. In this case, it is preferable that the two bubble generators are connected in parallel to the processing liquid flow path, and the processing liquid that has passed through the two bubble generators merges and is supplied to the processing tower 2.

[0141] Furthermore, although the above-described embodiment described an example in which the fine bubbles mixed into the processing liquid included both microbubbles and ultrafine bubbles, the fine bubbles mixed into the processing liquid may include only one of them.

[0142] Furthermore, although the above-described embodiment showed an example in which a substrate W is processed by a single-wafer processing unit 20, this invention may also be applied to a batch-type substrate processing apparatus that processes multiple substrates at once.

[0143] Although embodiments of the present invention have been described in detail, these are merely specific examples used to clarify the technical content of the present invention, and the present invention should not be interpreted as being limited to these specific examples. The scope of the present invention is limited only by the appended claims.

[0144] 1: Substrate processing device 3: Processing liquid supply device 6: Cabinet 7: Control device 17: Drainage piping 18: Drainage valve 20: Processing unit 21: Processing liquid tank 22, 22A, 22B, 22C, 22D: Tower supply piping 23: Unit supply piping 23a: Horizontal section 23b: Descending section 23c: Nozzle front bend section 24: Common piping 25: Branch piping 26: Branch flow meter 27: On / off valve 30: Pump 31: Bubble generator 32: Gas introduction line 33: Gas valve 36: Supply valve 37: Supply flow rate adjustment valve 38: Supply flow meter 40: Spin chuck 41: First nozzle 42: Second nozzle 44: Processing chamber 50: Rinse liquid supply system 51: Piping 52: Valve 60: Upstream piping section 61: Upstream piping section 62: Downstream piping section 63: Intermediate piping section 64: Supply piping bend 65: Branch piping 66: Return piping 66a: Horizontal section 66b: Downstream section 66c: Bend 71: First particle separator 72: Second particle separator 73: Third particle separator 74: Fourth particle separator 75: Fifth particle separator 76: Sixth particle separator 77: Seventh particle separator 80: Spiral tube 81, 83, 84: Branch piping 85: Filter 86, 88: Branch piping 89: Flow rate adjustment valve 97: Overflow drain piping E1: First electrode E2: Second electrode E11: First electrode E12: Second electrode F: Fine bubble P: Particle R: Processing liquid supply source W: Substrate

Claims

1. A method for removing particles from a processing liquid used to process a substrate, comprising: a step of circulating the processing liquid through a processing liquid channel; a step of supplying fine bubbles to the processing liquid circulating through the processing liquid channel; a step of causing particles in the processing liquid circulating through the processing liquid channel to adhere to the fine bubbles within the processing liquid channel; and a step of separating and collecting the fine bubbles to which the particles have adhered from the processing liquid circulating through the processing liquid channel.

2. The particle removal method according to claim 1, wherein the processing liquid flow path comprises a pipe having a bend, and the collection step comprises collecting the fine bubbles that are guided to a branch flow path branching off from the pipe in the tangential direction of the bend.

3. The particle removal method according to claim 2, wherein the piping includes a supply pipe that supplies the processing liquid from a processing liquid tank for storing the processing liquid to the substrate, and the bend includes a supply pipe bend provided in the supply pipe.

4. The particle removal method according to claim 3, wherein the supply pipe is connected to a nozzle that discharges the processing liquid toward the substrate, and the bend in the supply pipe includes a bend in front of the nozzle provided immediately before the nozzle.

5. The particle removal method according to claim 4, wherein the nozzle is located within a processing chamber that partitions a processing space for processing the substrate, and the nozzle front bend is provided within the processing chamber.

6. The particle removal method according to any one of claims 2 to 5, wherein the bent portion includes a spiral tube provided in the piping.

7. The particle removal method according to any one of claims 2 to 6, wherein the curved portion includes an upwardly convex curved portion.

8. The particle removal method according to any one of claims 1 to 7, wherein the collection step involves applying an electric field to the processing liquid flowing through the processing liquid channel to change the trajectory of the fine bubbles in the processing liquid, and guiding the fine bubbles to a branch channel branching off from the processing liquid channel for separation.

9. The particle removal method according to any one of claims 1 to 8, wherein the collection step involves capturing the fine bubbles by filtering the processing liquid with a filter provided in the middle of the processing liquid flow path, and guiding the fine bubbles captured by the filter to a branched flow path that branches off from the processing liquid flow path.

10. The particle removal method according to any one of claims 2 to 9, wherein the processing liquid channel includes a return pipe for returning the processing liquid to a processing liquid tank for storing the processing liquid, a portion of the processing liquid together with the fine bubbles is guided into the branch channel, and the processing liquid guided into the branch channel is returned to the processing liquid tank via the return pipe.

11. The particle removal method according to claim 10, further comprising the step of disposing of the treatment liquid in the treatment liquid tank.

12. The particle removal method according to claim 11, wherein the step of disposing of waste liquid involves disposing of the portion of the treatment liquid stored in the treatment liquid tank that is near the liquid surface.

13. The particle removal method according to any one of claims 10 to 12, wherein the collection step includes separating and collecting the fine bubbles to which the particles are attached from the processing liquid flowing through the return pipe, and guiding them to a waste channel for disposal.

14. The particle removal method according to any one of claims 1 to 13, further comprising the steps of: separating the fine bubbles to which the particles are attached from the processing liquid flowing through the processing liquid channel at multiple positions in the processing liquid channel, guiding them to multiple branched channels branching off from the multiple positions, guiding a portion of the processing liquid together with the fine bubbles into each branched channel; returning the processing liquid guided into at least one of the multiple branched channels to a processing liquid tank for storing the processing liquid; and discarding the processing liquid guided into at least one of the multiple branched channels without returning it to the processing liquid tank.

15. The particle removal method according to any one of claims 1 to 14, wherein the fine bubbles include microbubbles and ultrafine bubbles.

16. A substrate processing apparatus comprising: a nozzle for supplying a processing liquid to a substrate; a processing liquid channel through which the processing liquid flows; a bubble generator for supplying fine bubbles to the processing liquid flowing through the processing liquid channel; and a particle separator for separating and collecting the fine bubbles from the processing liquid flowing through the processing liquid channel, thereby separating particles attached to the fine bubbles.

17. The substrate processing apparatus according to claim 16, wherein the particle separator includes a bend in the piping that constitutes the processing liquid flow path and a branch flow path that branches off from the piping in a tangential direction to the bend.

18. The substrate processing apparatus according to claim 17, wherein the bent portion includes a spiral tube provided in the piping.

19. The substrate processing apparatus according to any one of claims 16 to 18, wherein the particle separator includes an electrode that applies an electric field to the processing liquid flowing through the processing liquid channel, and a branch channel into which fine bubbles whose trajectories are changed by the electric field are guided.

20. The substrate processing apparatus according to any one of claims 16 to 19, wherein the particle separator is provided in the middle of the processing liquid flow path and includes a filter that filters the processing liquid to capture the fine bubbles, and a branched flow path to which the fine bubbles captured by the filter are guided.

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