Fine bubble generator, processing liquid supply device, and substrate processing device.

Abstract

This technology provides a way to stabilize the fine bubble generation efficiency even when the liquid flow rate fluctuates. [Solution] The fine bubble generator has a first pipe section (21), a constricted pipe section (23), a second pipe section (25), and a multi-flow valve mechanism (27). The constricted pipe section (23) is located downstream of the first pipe section (21) and has a plurality of constricted flow channels (231) whose flow channel cross-sectional area decreases towards the downstream. The second pipe section (25) is located downstream of the constricted pipe section (23). The multi-flow valve mechanism (27) changes the number of flow channels among the plurality of constricted flow channels (231) that communicate with the first pipe section (21) and the second pipe section (25) according to the flow rate of the first pipe section (21).

Description

Technical Field

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[0001] The subject matter disclosed in this specification relates to a fine bubble generator, a processing liquid supply device, and a substrate processing device.

Background Art

[0002] Conventionally, a generator for generating fine bubbles (microbubbles) has been known. For example, in the device of Patent Document 1, a narrow gap and a gradually expanding region are continuously provided in a flow path through which a liquid flows. In this device, the flow rate of the liquid is increased by restricting the flow of the liquid in the narrow gap, and a pressure lower than that in the low-speed portion of the liquid flow is generated. Then, by releasing the pressure of the liquid flow in the gradually expanding region immediately after the narrow gap, micro- or nano-order fine bubbles are generated from the bubbles mixed in the water. Patent Document 1 also describes changing the bubble size by further narrowing the interval of the narrow gap.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional fine bubble generator, when the flow rate of the liquid fluctuates, the generation efficiency of the fine bubbles decreases due to changes in the flow velocity and the pressure applied to the liquid. Therefore, it has been difficult to stably generate fine bubbles of a desired size or amount.

[0005] An object of the present invention is to provide a technique capable of stabilizing the generation efficiency of fine bubbles even when the flow rate of the liquid fluctuates.

Means for Solving the Problems

[0006] To solve the above problems, the first embodiment is a fine bubble generator comprising: a first pipe section; a constricted pipe section located downstream of the first pipe section and having a plurality of constricted passages whose flow path cross-sectional area decreases toward the downstream direction; a second pipe section located downstream of the constricted pipe section; and a multi-flow valve mechanism that changes the number of passages among the plurality of constricted passages that communicate with the first pipe section and the second pipe section according to the flow rate of the first pipe section.

[0007] The second embodiment is a fine bubble generator according to the first embodiment, wherein the multi-flow valve mechanism opens and closes the flow path between the plurality of constricted flow paths and the first pipe section.

[0008] The third embodiment is a fine bubble generator according to the second embodiment, wherein the first tube section has an outer cylinder formed in the shape of a cylindrical shape extending in the axial direction and having a plurality of communication holes on its outer circumferential surface, and the multi-flow valve mechanism is inserted into the outer cylinder and is movable inside the outer cylinder along the axial direction, has an inner cylinder which is a bottomed cylindrical shape with a plurality of through holes on its outer circumferential surface and communicates with the first tube section, and has a biasing part which biases the inner cylinder upstream, the plurality of communication holes each communicate with a corresponding flow path among the plurality of narrowed flow paths, the plurality of communication holes in the outer cylinder have different lengths in the axial direction, the plurality of through holes in the inner cylinder are arranged so that they overlap with a corresponding communication hole among the plurality of communication holes in the outer cylinder in the radial direction perpendicular to the axial direction, and the number of through holes that overlap with the plurality of communication holes is changed as the inner cylinder moves in the axial direction relative to the outer cylinder in response to the liquid pressure on the bottom of the inner cylinder.

[0009] The fourth embodiment is a fine bubble generator according to the third embodiment, wherein the outer cylinder is inserted into the constricted tube section, and the plurality of constricted channels are arranged with circumferential spacing between the constricted tube section and the outer cylinder in the radial direction.

[0010] The fifth embodiment is a fine bubble generator according to the second embodiment, wherein the multi-flow valve mechanism comprises a plurality of on-off valves for opening and closing the flow paths between the first pipe section and each of the constricted flow paths, or between each of the constricted flow paths and the second pipe section, a pressure sensor for detecting the pressure inside the first pipe section, and a control unit for controlling the open and closed states of the plurality of on-off valves according to the pressure detected by the pressure sensor.

[0011] The sixth embodiment is a processing liquid supply device comprising a fine bubble generator according to the first or second embodiment, and a supply unit that supplies a processing liquid containing fine bubbles generated by the fine bubble generator to an object to be processed.

[0012] The seventh embodiment is a substrate processing apparatus comprising a support unit for supporting a substrate, and a supply unit for supplying a processing liquid containing a fine bubble generator according to the first or second embodiment and the fine bubbles generated by the fine bubble generator to the substrate supported by the support unit. [Effects of the Invention]

[0013] According to the first to seventh embodiments, the number of constricted passages communicating with the first and second pipe sections is changed according to the flow rate of the first pipe section, thereby reducing fluctuations in flow velocity and pressure in the constricted passages. As a result, even when the flow rate of the first pipe section fluctuates, the fine bubble generation efficiency can be stabilized.

[0014] According to the third embodiment of the fine bubble generator, the number of narrowed channels communicating with the first and second pipe sections is adjusted by mechanical elements, eliminating the need for sensors or complex electronic control systems, thus simplifying the overall structure. This reduces manufacturing and maintenance costs.

[0015] According to the fifth embodiment of the fine bubble generator, the number of narrowed flow channels communicating with the first and second pipe sections is adjusted by sensor control, allowing for free setting of conditions for opening and closing multiple on / off valves. Therefore, the system can be easily modified to suit the generation of fine bubbles. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows a cleaning apparatus equipped with a fine bubble generator according to the first embodiment. [Figure 2] This is a schematic cross-sectional view of a fine bubble generator according to the first embodiment. [Figure 3] Figure 2 is a schematic cross-sectional view of the fine bubble generator at the AA line position shown. [Figure 4] This is a schematic cross-sectional view of a fine bubble generator according to the second embodiment. [Figure 5] Figure 4 is a schematic cross-sectional view of the fine bubble generator at the BB line position shown. [Modes for carrying out the invention]

[0017] Embodiments of the present invention will be described below with reference to the attached drawings. Note that the components described in these embodiments are merely illustrative and are not intended to limit the scope of the present invention to them alone. In the drawings, for ease of understanding, the dimensions and number of parts may be exaggerated or simplified as needed.

[0018] <1. First Embodiment> Figure 1 shows a cleaning apparatus 100 equipped with a fine bubble generator 1 according to the first embodiment. The cleaning apparatus 100 is a substrate processing apparatus that cleans a substrate W with cleaning water. The substrate W is supported by, for example, a transport roller (not shown) and moves continuously in one direction horizontally by the transport roller. The transport roller is an example of a support part.

[0019] The cleaning device 100 includes a supply unit 10. The supply unit 10 includes a high-pressure nozzle 11, a supply pipe 13, a pump 15, a tank 17, and a control unit 19. The high-pressure nozzle 11 has a spray pipe 111 and a plurality of nozzle parts 113. The spray pipe 111 extends in a direction orthogonal to the conveyance direction of the substrate W. Cleaning water is supplied to the spray pipe 111. The plurality of nozzle parts 113 are arranged at equal intervals along the spray pipe 111. Each nozzle part 113 is designed to inject the cleaning water supplied from the spray pipe 111 at high pressure while dispersing it.

[0020] The supply pipe 13 supplies cleaning water to the high-pressure nozzle 11. The supply pipe 13 connects the tank 17 and the spray pipe 111 of the high-pressure nozzle 11, and supplies the cleaning water to the high-pressure nozzle 11 by the force of the pump 15. The tank 17 stores the cleaning water supplied to the supply pipe 13. Incidentally, the cleaning water used for cleaning the substrate W may be recovered in the tank 17 to circulate the cleaning water.

[0021] The fine bubble generator 1 is arranged, for example, in the middle of the supply pipe 13. The fine bubble generator 1 can generate fine bubbles with a diameter of less than 100 μm (micrometers), and in particular, can generate ultra-fine bubbles. Among the fine bubbles, bubbles with a diameter of less than 100 μm and 1 μm or more are microbubbles, and bubbles with a diameter of less than 1 μm are ultra-fine bubbles. Fine bubbles are more stable than ordinary bubbles and can exist in a liquid for a long time. Among the fine bubbles, ultra-fine bubbles are considered to be particularly useful in cleaning effects and other applications.

[0022] As shown in Figure 1, the cleaning water containing fine bubbles generated in the fine bubble generator 1 is sent to the high-pressure nozzle 11 through the supply pipe 13. Then, the cleaning water containing fine bubbles is supplied to the substrate W from each nozzle section 113 of the high-pressure nozzle 11. As a result, the substrate W can be cleaned with cleaning water containing fine bubbles, thus achieving a high cleaning effect. In addition, the amount of cleaning water consumed can be reduced, thereby reducing the environmental impact.

[0023] In the cleaning apparatus 100, the supply unit 10 supplies a processing liquid (cleaning liquid) containing fine bubbles generated by the fine bubble generator 1 to the object to be processed (substrate W). An apparatus equipped with the fine bubble generator 1 and the supply unit 10 corresponds to a "processing liquid supply apparatus". Furthermore, an apparatus equipped with a support unit (transport roller) for supporting the substrate W, the fine bubble generator 1, and the supply unit 10 corresponds to a "substrate processing apparatus".

[0024] It is not mandatory for the fine bubble generator 1 to be installed in the supply piping 13. For example, the fine bubble generator 1 may be installed in piping for supplying the treated liquid to the tank 17.

[0025] <Fine bubble generator> Figure 2 is a schematic cross-sectional view of the fine bubble generator 1 according to the first embodiment. Figure 3 is a schematic cross-sectional view of the fine bubble generator 1 at the position indicated by line AA in Figure 2. The white block arrows shown in Figure 2 indicate the direction of liquid flow in the fine bubble generator 1. As shown in Figure 2, the fine bubble generator 1 comprises a first pipe section 21, a constricted pipe section 23, a second pipe section 25, and a multi-flow valve mechanism 27.

[0026] The first pipe section 21 is located furthest upstream in the fine bubble generator 1. The constricted pipe section 23 is located downstream of the first pipe section 21. The second pipe section 25 is located downstream of the constricted pipe section 23. That is, the fine bubble generator 1 comprises the first pipe section 21, the constricted pipe section 23, and the second pipe section 25 in order from upstream to downstream. Liquid flowing into the first pipe section 21 passes through the constricted pipe section 23 and then flows to the second pipe section 25. The upstream side of the first pipe section 21 is connected to a supply pipe 13 in a cleaning device 100, for example. The downstream side of the second pipe section 25 is also connected to a supply pipe 13, for example. The first pipe section 21, the constricted pipe section 23, and the second pipe section 25 are, for example, cylindrical. The constricted pipe section 23 has a portion with a larger inner diameter (inner width) than the first pipe section 21 and the second pipe section 25.

[0027] The first pipe section 21, the constricted pipe section 23, and the second pipe section 25 are arranged coaxially with respect to axis A1. In the following description, the direction parallel to axis A1 is referred to as the "axial direction." In the axial direction, the direction from the constricted pipe section 23 toward the second pipe section 25 is referred to as "one axial direction," and the opposite direction is referred to as "the other axial direction." The direction perpendicular to axis A1 is referred to as the "radial direction." In the radial direction, the direction approaching axis A1 is referred to as "radial inward," and the direction moving away from axis A1 is referred to as "radial outward." The direction of rotation around axis A1 is referred to as the "circumferential direction."

[0028] The first pipe section 21 has an outer cylinder 211. The outer cylinder 211 is formed as a bottomed cylindrical shape extending in the axial direction. The outer cylinder 211 is located at the downstream end (one end in the axial direction) of the first pipe section 21. The outer cylinder 211 is inserted into the constricted pipe section 23 and fixed within the constricted pipe section 23. More specifically, as shown in Figures 2 and 3, a gap is formed radially between the outer cylinder 211 and the constricted pipe section 23, and an annular connecting member 230 is placed in this gap, and the outer cylinder 211 of the first pipe section 21 is fixed in a certain position within the constricted pipe section 23 via the connecting member 230.

[0029] Multiple (six in this example) communication holes 213 are formed on the outer circumferential surface of the outer cylinder 211. Figure 2 shows two of these communication holes, 213a and 213b. The multiple communication holes 213 function as passages for liquid, connecting the inside and outside of the outer cylinder 211. Communication here refers to a state in which fluid is connected in a way that allows it to flow.

[0030] The multiple communication holes 213 are arranged at equal intervals in the circumferential direction. The multiple communication holes 213 have different lengths in the axial direction. For example, communication hole 213a is longer in the axial direction than communication hole 213b. The multiple communication holes 213 are, for example, circular or oval in shape. However, the shape of the communication holes can be changed arbitrarily.

[0031] The constricted pipe section 23 has a plurality (six in this example) of constricted flow channels 231. The plurality of constricted flow channels 231 are arranged radially inward of the constricted pipe section 23 and radially outward of the outer cylinder 211. More specifically, the plurality of constricted flow channels 231 are provided in the connecting member 230 and are formed as holes that penetrate the connecting member 230 in the axial direction. The constricted flow channels 231 are flow channels in which the cross-sectional area of ​​the flow channel gradually decreases as you move downstream (to one side in the axial direction), and then the cross-sectional area of ​​the flow channel gradually increases. The outlet side (downstream side and one side in the axial direction) of the plurality of constricted flow channels 231 is in communication with the second pipe section 25. As shown in Figure 3, the plurality of constricted flow channels 231 are arranged at equal intervals in the circumferential direction inside the constricted pipe section 23 and outside the outer cylinder 211.

[0032] When liquid passes through the constricted channel 231, the flow velocity of the liquid increases at the inlet side of the constricted channel 231 because the cross-sectional area of ​​the channel decreases. As the flow velocity increases, the pressure on the liquid decreases according to Bernoulli's principle. Therefore, the liquid pressure drops sharply in the constricted channel 231. When the pressure drops, gases (such as air) dissolved in the liquid precipitate as bubbles (cavitation). In the constricted channel 231, this pressure drop generates a large number of tiny bubbles.

[0033] Furthermore, at the outlet side of the constricted channel 231, the channel cross-sectional area increases again, causing the liquid flow velocity to decrease and the liquid pressure to return to its original level. This return of pressure causes the bubbles generated in the constricted channel 231 to shrink. In other words, the diameter of the bubbles becomes very small. As a result, fine bubbles with a diameter of 1 μm or less are formed.

[0034] Although not shown in the diagram, a pipe (not shown) for supplying gas to the liquid may be provided at or upstream of the constricted pipe section 23. By supplying gas to the liquid in the pipe, the amount of fine bubbles generated can be increased.

[0035] The multiple communication holes 213 in the outer cylinder 211 are provided to correspond one-to-one with the multiple constricted flow channels 231. The multiple communication holes 213 communicate with different constricted flow channels 231 from each other. For example, as shown in Figure 2, the constricted flow channel 231a that communication hole 213a communicates with is different from the constricted flow channel 231b that communication hole 213b communicates with.

[0036] <Multi-flow valve mechanism> The multi-flow valve mechanism 27 is a mechanism that changes the number of passages among the multiple constricted passages 231 that communicate with the first pipe section 21 and the second pipe section 25, according to the flow rate of the first pipe section 21. The multi-flow valve mechanism 27 is a mechanism that opens and closes the passages upstream of the multiple constricted passages 231, according to the flow rate of the first pipe section 21. The multi-flow valve mechanism 27 has an inner cylinder 31 and a biasing section 33.

[0037] The inner cylinder 31 is a bottomed cylindrical member inserted into the outer cylinder 211. A small gap is formed between the inner cylinder 31 and the outer cylinder 211 in the radial direction, and the inner cylinder 31 is slidable within the outer cylinder 211 along the axial direction. The inside of the inner cylinder 31 is in communication with the outer cylinder 211 of the first pipe section 21. Multiple (six in this example) through holes 311 are provided on the outer circumferential surface of the inner cylinder 31. The multiple through holes 311 are arranged at equal intervals in the circumferential direction.

[0038] The biasing part 33 biases the inner cylinder 31 upstream (towards the first pipe section 21). The biasing part 33 is located on one axial side relative to the inner cylinder 31. The axial end of the biasing part 33 is fixed to the bottom inside the outer cylinder 211. The axial end of the biasing part 33 is fixed to the bottom of the inner cylinder 31. The biasing part 33 is an elastic body such as a coil spring. The inner cylinder 31 is positioned so that the axial pressure it receives from the liquid flowing from the first pipe section 21 into the inner cylinder 31 balances the axial biasing force it receives from the biasing part 33 in the other direction.

[0039] Multiple through-holes 311 in the inner cylinder 31 are arranged to correspond one-to-one with multiple communication holes 213 in the outer cylinder 211. That is, one through-hole 311 corresponds to one communication hole 213 and one constricted flow path 231. Each through-hole 311 is positioned so that it can radially overlap with the corresponding communication hole 213 as the inner cylinder 31 moves axially. Overlapping means that the through-hole 311 is contained within the opening range of the communication hole 213. When a particular through-hole 311 overlaps with the corresponding communication hole 213, the liquid inside the inner cylinder 31 can enter the constricted flow path 231 corresponding to the communication hole 213 through that through-hole 311 and communication hole 213.

[0040] For example, in the state shown in Figure 2, the communication hole 213a overlaps with the corresponding through hole 311a. That is, the through hole 311a is located within the opening range of the communication hole 213a and is therefore open. On the other hand, the communication hole 213b does not overlap with the corresponding through hole 311b. That is, the through hole 311b is located outside the opening range of the communication hole 213b and is closed by the outer cylinder 211. Therefore, the liquid in the inner cylinder 31 enters the constricted flow path 231a through the through hole 311a and the communication hole 213a. On the other hand, since the through hole 311b is closed, the liquid is prevented from entering the corresponding constricted flow path 231b.

[0041] When the flow rate of the first pipe section 21 increases, the inner cylinder 31 slides in one axial direction, causing the through hole 311b to overlap with the communication hole 213b. That is, the through hole 311b comes into contact with the opening range of the communication hole 213b. As a result, the liquid in the inner cylinder 31 can enter the corresponding constricted passage 231b through the through hole 311b and the communication hole 213b. Thus, with the fine bubble generator 1, when the flow rate of the first pipe section 21 increases, the number of constricted passages 231 communicating with the first pipe section 21 and the second pipe section 25 increases, dispersing the liquid and reducing pressure loss. This reduces fluctuations in the liquid velocity and pressure in each constricted passage 231, thereby suppressing a decrease in the fine bubble generation efficiency.

[0042] Furthermore, if the flow rate of the first pipe section 21 decreases, the inner cylinder 31 slides in the other axial direction due to the biasing force of the biasing section 33. As a result, some of the through holes 311 are closed, and the number of constricted passages 231 communicating with the first pipe section 21 and the second pipe section 25 decreases. This reduces the decrease in the flow velocity and pressure of the liquid passing through the constricted passages 231, thereby suppressing a decrease in the efficiency of fine bubble generation.

[0043] As described above, with the fine bubble generator 1, the number of narrowed channels 231 communicating with the first pipe section 21 and the second pipe section 25 is adjusted according to the flow rate of the first pipe section 21. Therefore, even if the flow rate of the first pipe section 21 fluctuates, the fine bubble generation efficiency can be stabilized.

[0044] Furthermore, the fine bubble generator 1 allows for the adjustment of the number of constricted channels 231 communicating with the first pipe section 21 and the second pipe section 25 using mechanical elements. Therefore, it eliminates the need for sensors and complex electronic control systems, simplifying the overall structure. This reduces manufacturing and maintenance costs.

[0045] <2. Second Embodiment> Next, a second embodiment will be described. In the following description, elements having the same function as those already described will be given the same reference numeral or a reference numeral with an additional alphabetic character, and detailed descriptions may be omitted.

[0046] Figure 4 is a schematic cross-sectional view of the fine bubble generator 1A according to the second embodiment. Figure 5 is a schematic cross-sectional view of the fine bubble generator 1A at the position of line BB shown in Figure 4. As shown in Figure 4, the fine bubble generator 1A comprises, in order from upstream to downstream, a first pipe section 21, a constricted pipe section 23a, and a second pipe section 25. The constricted pipe section 23a has a portion whose inner diameter (inner width) is larger than that of the first pipe section 21 and the second pipe section 25.

[0047] The constricted pipe section 23a has a plurality of (seven in this example) constricted passages 231. The plurality of constricted passages 231 are formed in a partition member 233 installed within the constricted pipe section 23. More specifically, the partition member 233 is provided with a plurality of (seven in this example) branch passages 235 that penetrate in the axial direction. One constricted passage 231 is formed in the middle of each branch passage 235. In other words, the plurality of constricted passages 231 are provided in a one-to-one correspondence with the plurality of branch passages 235. As shown in Figure 5, the plurality of branch passages 235 and the plurality of constricted passages 231 are arranged to be dispersed in the radial direction.

[0048] The fine bubble generator 1A is equipped with a multi-flow valve mechanism 27a. The multi-flow valve mechanism 27a comprises a plurality of (seven in this example) on-off valves 351, a pressure sensor 353, and a control unit 355. One on-off valve 351 is provided in each of the plurality of branched flow paths 235. That is, the plurality of on-off valves 351 are provided in one-to-one correspondence with the plurality of branched flow paths 235. The on-off valve 351 is a butterfly valve that opens and closes the branched flow path 235 by rotating a disc capable of closing the branched flow path 235 by 90°. However, the on-off valve 351 may be any type of valve as long as it is capable of opening and closing the branched flow path 235. The on-off valve 351 is located upstream (on the other axial side) of the constricted flow path 231. That is, the on-off valve 351 is an element that opens and closes the flow path (branched flow path 235) between the corresponding constricted flow path 231 and the first pipe section 21.

[0049] The pressure sensor 353 is installed in the first pipe section 21 and detects the pressure (water pressure) inside the first pipe section 21. The pressure sensor 353 is electrically connected to the control unit 355 and converts the detected pressure into an electrical signal which is output to the control unit 355. The control unit 355 consists of a computer equipped with a processor such as a CPU and memory such as RAM. However, the control unit 355 may also consist of electrical circuits such as a programmable logic controller (PLC), a relay circuit, or a PID controller.

[0050] The control unit 355 dynamically controls the open / closed state of the multiple on-off valves 351 in accordance with the pressure detected by the pressure sensor 353. More specifically, each time the pressure detected by the pressure sensor 353 exceeds a predetermined threshold, the control unit 355 opens the multiple on-off valves 351 one by one in a stepwise manner. Conversely, each time the pressure detected by the pressure sensor 353 falls below a predetermined threshold, the control unit 355 closes the multiple on-off valves 351 one by one in a stepwise manner. In other words, the control unit 355 controls the open / closed state of the multiple on-off valves 351 so that the magnitude of the pressure detected by the pressure sensor 353 is proportional to the number of on-off valves 351 that have been opened.

[0051] As the flow rate in the first pipe section 21 increases, the pressure detected by the pressure sensor 353 also increases. In other words, the pressure detected by the pressure sensor 353 has a positive correlation with the flow rate in the first pipe section 21. Therefore, in the fine bubble generator 1A, a number of on / off valves 351 corresponding to the flow rate in the first pipe section 21 are opened. That is, a number of constricted passages 231 corresponding to the flow rate in the first pipe section 21 are connected to the first pipe section 21 and the second pipe section 25. As a result, even if the flow rate in the first pipe section 21 fluctuates, the flow velocity and pressure in each constricted passage 231 are adjusted to values ​​suitable for fine bubble generation, thereby stabilizing the fine bubble generation efficiency.

[0052] Furthermore, with the fine bubble generator 1A, the number of narrowed channels 231 communicating with the first pipe section 21 and the second pipe section 25 is adjusted by sensor control, allowing for the free setting of conditions (thresholds) for opening and closing multiple on / off valves 351. Therefore, the system can be easily modified to suit the generation of fine bubbles.

[0053] <3. Variant Example> Although embodiments have been described above, the present invention is not limited to those described above, and various modifications are possible.

[0054] For example, in the fine bubble generator 1A of the second embodiment, the multiple on-off valves 351 are located upstream of the corresponding constricted passage 231, and each opens and closes the passage (branch passage 235) between the first pipe section 21 and the corresponding constricted passage 231. However, each on-off valve 351 may be located downstream of the constricted passage 231. In this case, the multiple on-off valves 351 each open and close the passage (branch passage 235) between the corresponding constricted passage 231 and the second pipe section 25.

[0055] Although the invention has been described in detail, the above description is illustrative in all aspects and the invention is not limited thereto. Numerous variations that are not illustrated can be conceived without departing from the scope of the invention. The configurations described in each of the above embodiments and each variation can be appropriately combined or omitted as long as they do not conflict with each other.

Description of Reference Numerals

[0056] 1, 1A: Fine bubble generator 10: Supply unit 21: First pipe portion 23, 23a: Narrow pipe portion 25: Second pipe portion 27, 27a: Multi-channel valve mechanism 31: Inner cylinder 33: Biasing portion 100: Cleaning device (substrate processing device) 211: Outer cylinder 213: Communication hole 231: Narrow flow path 235: Branch flow path 311: Through hole 351: On-off valve 353: Pressure sensor 355: Control unit W: Substrate

Claims

1. It is a fine bubble generator, The first pipe section and, A constricted pipe section located downstream of the first pipe section, having multiple constricted channels whose cross-sectional area of ​​the flow path decreases toward the downstream direction, A second pipe section located downstream of the aforementioned narrowed pipe section, A multi-flow valve mechanism that changes the number of constricted flow paths that communicate with the first and second pipe sections from among the plurality of constricted flow paths, according to the flow rate of the first pipe section, A fine bubble generator equipped with the following features.

2. A fine bubble generator according to claim 1, The multi-flow valve mechanism is a fine bubble generator that opens and closes the flow path between the plurality of narrowed flow paths and the first pipe section.

3. A fine bubble generator according to claim 2, The first pipe section has an outer cylinder formed in an axial direction and having a plurality of communication holes on its outer surface. The multi-flow valve mechanism is, An inner cylinder is inserted into the outer cylinder, is movable within the outer cylinder along the axial direction, has an interior that communicates with the first pipe section, and is a bottomed cylindrical shape with a plurality of through holes on its outer surface, A biasing part that biases the inner cylinder toward the upstream side, It has, The plurality of communication holes each communicate with the corresponding flow path among the plurality of narrowed flow paths, The plurality of communication holes in the outer cylinder have different lengths in the axial direction. The plurality of through holes in the inner cylinder are arranged so as to overlap with corresponding communication holes among the plurality of communication holes in the outer cylinder in a radial direction perpendicular to the axial direction. A fine bubble generator in which, in response to the liquid pressure at the bottom of the inner cylinder, the inner cylinder moves axially relative to the outer cylinder, thereby changing the number of through holes that overlap with the plurality of communication holes among the plurality of through holes.

4. A fine bubble generator according to claim 3, The outer cylinder is inserted into the constricted pipe section. The fine bubble generator is characterized in that the plurality of constricted channels are arranged circumferentially at intervals between the radially constricted tube section and the outer cylinder.

5. A fine bubble generator according to claim 2, The multi-flow valve mechanism is, A plurality of on / off valves for opening and closing the flow path between the first pipe section and each of the constricted flow paths, or the flow path between each of the constricted flow paths and the second pipe section, Pressure recovery for detecting the pressure inside the first pipe section, A control unit that controls the open / closed state of the plurality of on / off valves according to the pressure detected by the pressure sensor, A fine bubble generator equipped with the following features.

6. A processing liquid supply device, A fine bubble generator according to claim 1 or claim 2, A supply unit that supplies a processing liquid containing fine bubbles generated by the fine bubble generator to the object to be processed, A processing liquid supply device equipped with the following features.

7. A substrate processing apparatus, Support part that supports the circuit board, A fine bubble generator according to claim 1 or claim 2 and A supply unit that supplies a processing liquid containing fine bubbles generated by the fine bubble generator to the substrate supported by the support unit, A substrate processing apparatus comprising:

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