Mixed liquid manufacturing device

Abstract

To preferably manufacture a mixed liquid just before cleaning of a wafer.SOLUTION: When cleaning a wafer 100, a mixed liquid manufacturing apparatus 10 mixes a first liquid and a second liquid to manufacture a mixed liquid 403, and discharges the manufactured mixed liquid 403 to the wafer 100. Then, when manufacturing the mixed liquid 403, an air pressure in a mixing chamber 15 is set to a predetermined negative pressure value lower than that of an outside pressure by using an ejector 31, the mixed liquid 403 is prevented from leaking from a discharge opening 18. Further, when cleaning the wafer 100, the mixed liquid 403 is discharged from the discharge opening 18 by increasing the air pressure in the mixing chamber 15. This eliminates the need to provide a valve in a discharge path 17 communicated to the mixing chamber 15. Therefore, when discharging the mixed liquid 403, the mixed liquid 403 does not remain in the discharge path 17 communicated with the mixing chamber 15.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a mixed liquid manufacturing apparatus.

Background Art

[0002] When cleaning a wafer after etching, as disclosed in Patent Documents 1 and 2, for example, as cleaning water used, a piranha solution in which concentrated sulfuric acid (H 2 SO 4 ) and 30% hydrogen peroxide solution (H 2 O 2 ) are mixed is used. This piranha solution mixes the above two types of liquids at a mixing ratio of 3 to 1, 4 to 1, or 7 to 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] A piranha solution cannot be put in a sealed container because it generates gas, and it cannot be stored for a long time because it deteriorates quickly due to gas generation. Therefore, every time a piranha solution is used, it is necessary to mix the above two types of liquids.

[0005] In addition, a piranha solution attacks plastic. Therefore, in order to mix the two types of liquids, a glass container, a container made of a fluororesin, or a container coated with a fluororesin is used.

[0006] Therefore, an object of the present invention is to satisfactorily manufacture a mixed liquid immediately before cleaning when cleaning wafers one by one using a mixed liquid such as a piranha solution.

Means for Solving the Problem

[0007] The mixed liquid manufacturing apparatus (this mixed liquid manufacturing apparatus) of the present invention is a mixed liquid manufacturing apparatus for manufacturing a mixed liquid obtained by mixing at least two liquids, and includes a mixing chamber surrounded by a bottom plate, side plates, and a top plate, a first liquid inlet for injecting a first liquid into the mixing chamber, a second liquid inlet for injecting a second liquid into the mixing chamber, a discharge path penetrating the bottom plate for discharging the mixed liquid obtained by mixing the first liquid and the second liquid from the mixing chamber, a suction port for communicating the inside of the mixing chamber with a suction source to suck the gas in the mixing chamber, a suction pressure adjustment valve for adjusting the suction pressure when sucking the gas from the suction port, and a control unit. The control unit communicates the mixing chamber with the suction source to make the air pressure in the mixing chamber a predetermined negative pressure value lower than the atmospheric pressure in order to mix the first liquid and the second liquid without discharging them from the lower end of the discharge path, and by increasing the air pressure in the mixing chamber above the predetermined negative pressure value, discharges all the mixed liquid in the mixing chamber and the discharge path from the lower end of the discharge path. The control unit sucks the gas in the mixing chamber from the suction port, and includes a third control unit that controls the suction pressure adjustment valve so as to suck air into the mixing chamber from the lower end of the discharge path and mix the first liquid and the second liquid 。 In this mixed liquid manufacturing apparatus, the suction source may be an ejector, and the suction pressure adjustment valve may adjust the suction pressure by adjusting the amount of air supplied to the ejector. In this mixed liquid manufacturing apparatus, the control unit may include a first control unit that makes the air pressure in the mixing chamber a first negative pressure value when injecting the first liquid into the mixing chamber, and a second control unit that makes the air pressure in the mixing chamber a second negative pressure value greater in the negative pressure direction than the first negative pressure value when injecting the second liquid into the mixing chamber in addition to the first liquid.

Advantages of the Invention

[0008] In this mixed liquid manufacturing apparatus, when cleaning an object to be cleaned such as a wafer, a first liquid and a second liquid are mixed to manufacture a mixed liquid, and the manufactured mixed liquid is discharged. When manufacturing the mixed liquid, the air pressure in the mixing chamber is set to a predetermined negative pressure value lower than the external air pressure using a suction source, so that the first liquid, the second liquid, and the mixed liquid do not leak from the lower end of the discharge path penetrating the bottom plate of the mixing chamber. Also, when using the mixed liquid, by raising the air pressure in the mixing chamber above the predetermined negative pressure value, all the mixed liquid in the mixing chamber and the discharge path is discharged from the lower end of the discharge path.

[0009] Therefore, in this mixed liquid manufacturing apparatus, there is no need to provide a valve with which the mixed liquid comes into contact in the discharge path communicating with the mixing chamber where the mixed liquid is stored. For this reason, when discharging the mixed liquid, it is possible to prevent the mixed liquid from remaining in the discharge path communicating with the mixing chamber.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] The wafer cleaning apparatus 1 according to the present embodiment shown in FIG. 1 is an apparatus for cleaning a wafer 100 as an object to be cleaned. The wafer 100 to be cleaned in the present embodiment is, for example, of a small diameter (for example, about half an inch).

[0012] As shown in FIG. 1, the wafer cleaning apparatus 1 includes a mixed solution manufacturing apparatus 10 for manufacturing a mixed solution, a cleaning tank unit 50 in which the wafer 100 is disposed, and a wet scrubber 70 for treating gas.

[0013] The mixed solution manufacturing apparatus 10 mixes a first liquid and a second liquid to manufacture a mixed solution as a cleaning liquid. The mixed solution is, for example, a piranha solution. In this case, concentrated sulfuric acid (H 2 SO 4 ) is used as the first liquid, and 30% hydrogen peroxide solution (H 2 O 2 ) is used as the second liquid. In this case, the mixing ratio of the first liquid to the second liquid is, for example, 3:1, 4:1, or 7:1.

[0014] The mixed solution manufacturing apparatus 10 includes a mixing container 11 for mixing the first liquid and the second liquid. The mixing container 11 is, for example, a glass container, a container formed of a fluororesin, or a container coated with a fluororesin. The mixing container 11 includes a cylindrical side plate 12, a top plate 13 that closes the upper surface of the side plate 12, and a bottom plate 14 that closes the lower surface of the side plate 12. The space surrounded by these side plate 12, top plate 13, and bottom plate 14 is the mixing chamber 15.

[0015] At substantially the center of the bottom plate 14, a discharge path 17 for discharging the mixed solution is provided so as to penetrate the bottom plate 14. The discharge path 17 communicates with the mixing chamber 15. The lower end of the discharge path 17 is a discharge port 18 from which the mixed solution is discharged. Further, the upper surface of the bottom plate 14 faces the mixing chamber 15, and the upper surface is formed in a mortar shape in which the upper end of the discharge path 17 is the lowest.

[0016] In addition, the top plate 13 is provided with a first liquid injection port 20 for injecting the first liquid into the mixing chamber 15, a second liquid injection port 25 for injecting the second liquid into the mixing chamber 15, and a suction port 30 for sucking the gas in the mixing chamber 15.

[0017] The first liquid inlet 20 is a nozzle for injecting the first liquid into the mixing chamber 15, and is provided on the top plate 13 so as to penetrate the top plate 13. The lower end of the first liquid inlet 20 is opened into the mixing chamber 15. The upper end of the first liquid inlet 20 is connected to the first liquid supply source 21 via the first pipe 22. A first valve 23 is arranged in the first pipe 22. The first valve 23 switches the communication state between the first liquid supply source 21 and the first liquid inlet 20.

[0018] The second liquid inlet 25 is a nozzle for injecting the second liquid into the mixing chamber 15, and is provided on the top plate 13 so as to penetrate the top plate 13. The lower end of the second liquid inlet 25 is opened into the mixing chamber 15. The upper end of the second liquid inlet 25 is connected to the second liquid supply source 26 via the second pipe 27. A second valve 28 is arranged in the second pipe 27. The second valve 28 switches the communication state between the second liquid supply source 26 and the second liquid inlet 25. Incidentally, the first liquid inlet 20 and the second liquid inlet 25 may be provided on the side plate 12 by penetrating the upper part of the side plate 12 of the mixing chamber 15.

[0019] The suction port 30 is a suction nozzle used to connect the inside of the mixing chamber 15 to a suction source and suck the gas in the mixing chamber 15, and is provided on the top plate 13 so as to penetrate the top plate 13. The lower end of the suction port 30 is opened into the mixing chamber 15. The upper end of the suction port 30 is connected to the ejector 31 via the suction pipe 32. A suction valve 33 is arranged in the suction pipe 32. The suction valve 33 switches the communication state between the ejector 31 and the suction port 30.

[0020] The ejector 31 is a suction source that generates a suction force using air supplied from the outside. That is, when air is supplied to the ejector 31 from the outside, the ejector 31 sucks the gas in the mixing chamber 15 through the suction port 30 and the suction pipe 32.

[0021] In this embodiment, an air source 35 is connected to an ejector 31 via a first air pipe 36. That is, when air from the air source 35 is supplied to the ejector 31, the ejector 31 sucks the gas in the mixing chamber 15 through a suction port 30 and a suction pipe 32. Since the ejector 31 can generate a stronger suction force as the amount of air supplied from the air source 35 increases, the suction pressure when sucking the gas in the mixing chamber 15 from the suction port 30 can be increased. In this embodiment, the ejector 31 is formed of, for example, a fluororesin.

[0022] The air source 35 includes, for example, a compressor and is used to supply air to the ejector 31. A suction pressure regulating valve 38 and an air supply on-off valve 37 are arranged in the first air pipe 36 in order from the air source 35 toward the ejector 31 side. The air supply on-off valve 37 switches the communication state between the ejector 31 and the air source 35. Note that a configuration not using the air supply on-off valve 37 may also be adopted.

[0023] The suction pressure regulating valve 38 is, for example, a proportional control solenoid valve and is used to adjust the amount of air sent from the air source 35 to the ejector 31 when the air supply on-off valve 37 is open. That is, the suction pressure regulating valve 38 adjusts the suction pressure when sucking the gas in the mixing chamber 15 from the suction port 30 by adjusting the amount of air supplied from the air source 35 to the ejector 31. Note that the suction pressure regulating valve 38 may be a manual needle valve.

[0024] In addition, an exhaust pipe 39 is connected to the ejector 31. The exhaust pipe 39 is a pipe for exhausting the gas sucked from the mixing chamber 15 by the ejector 31 through the suction port 30 and the suction pipe 32 toward the wet scrubber 70. The exhaust pipe 39 communicates with the suction pipe 32 via the ejector 31. When air is not supplied to the ejector 31 from the air source 35, the function as a suction source of the ejector 31 stops, and the inside of the exhaust pipe 39 becomes the outside air pressure. Therefore, in this case, if the suction valve 33 is open, the suction pipe 32 communicating with the exhaust pipe 39, as well as the suction port 30 and the mixing chamber 15 communicating with the suction pipe 32, also become the outside air pressure.

[0025] As shown in FIG. 1, the cleaning tank unit 50 is disposed below the mixed liquid manufacturing apparatus 10. The cleaning tank unit 50 includes a cleaning tank 51 for cleaning the wafer 100 and a holding table 53 disposed in the cleaning tank 51 for holding the wafer 100. The cleaning tank 51 and the holding table 53 are formed of, for example, glass or a fluororesin, or are coated with a fluororesin.

[0026] The holding table 53 has a holding surface 54 made of a porous material. The holding surface 54 sucks and holds the wafer 100 by communicating with a suction source (not shown). The center of the holding surface 54 is located below the discharge port 18 in the mixed liquid manufacturing apparatus 10. Note that the holding table 53 may be formed of a dense body instead of a porous material. The holding table 53 made of a dense body forms a plurality of pores in the holding surface 54 and sucks and holds the wafer 100 by communicating the pores with a suction source. Note that the holding table 53 may be configured to partially contact the lower surface of the wafer 100 to support the wafer 100 without sucking and holding the wafer 100. Further, the holding table 53 may be configured to support the outer peripheral portion of the wafer 100.

[0027] Further, the cleaning tank unit 50 has a rotating unit 57 that rotates the holding table 53. The rotating unit 57 rotates the holding table 53 that holds the wafer 100 by the holding surface 54.

[0028] The rotating unit 57 has a motor 55 disposed outside (below) the bottom 52 of the cleaning tank 51, and a spindle 56 that extends through the bottom 52 and is rotated by the motor 55. The upper end of the spindle 56 is connected to the lower surface of the holding table 53. The lower end of the spindle 56 is connected to the motor 55. Note that the penetrating portion of the spindle 56 in the bottom 52 is sealed by a seal member 58 made of an O-ring or the like.

[0029] In the holding table 53 having such a configuration, the wafer 100 is held on the holding surface 54 so that, for example, the center of the spindle 56 rotated by the motor 55 passes through the center of the wafer 100. Then, when the spindle 56 is rotated by the motor 55 of the rotating unit 57, the holding table 53 holding the wafer 100 is rotated.

[0030] In the cleaning tank unit 50, the wafer 100 is cleaned by discharging the mixed liquid produced by the mixed liquid production device 10 onto the wafer 100. The mixed liquid used for cleaning is discharged to an external processing device (not shown) through a drain port 59 provided in the bottom 52 of the cleaning tank 51.

[0031] The wet scrubber 70 treats the gas exhausted from the ejector 31 and flowing in the exhaust pipe 39 to remove its toxic components. As shown in FIG. 1, the wet scrubber 70 includes a housing 71 that takes in and discharges the gas in the exhaust pipe 39. Further, the wet scrubber 70 includes a shower nozzle 72 communicated with a water source 73 and a decontamination filter 74 in the housing 71.

[0032] The wet scrubber 70 having such a configuration removes toxic components from the gas taken in from the exhaust pipe 39 by the water droplets 200 supplied from the shower nozzles 72 and the decontamination filter 74, and discharges it to the outside from the exhaust port 75 formed in the upper part of the housing 71. The used water is discharged to the outside, for example, through a drain port (not shown) formed at the bottom of the housing 71.

[0033] Further, the mixed liquid manufacturing device 10 of the wafer cleaning device 1 is provided with a control unit 40. The control unit 40 controls each member of the mixed liquid manufacturing device 10, the cleaning tank unit 50, and the wet scrubber 70 to clean the wafer 100. In particular, the control unit 40 controls each valve of the mixed liquid manufacturing device 10 to manufacture a mixed liquid by mixing a first liquid and a second liquid as a cleaning liquid, and performs an operation of discharging the manufactured mixed liquid onto the wafer 100.

[0034] The cleaning operation of the wafer 100 by the control unit 40 will be described below. In the cleaning of the wafer 100, first, an operator or the control unit 40 places the wafer 100, which is an object to be cleaned, on the holding surface 54 of the holding table 53 in the cleaning tank unit 50 of the wafer cleaning device 1. Then, the control unit 40 controls a suction source (not shown) to suck and hold the wafer 100 by the holding surface 54. Next, the control unit 40 manufactures a mixed liquid.

[0035] (Mixed Liquid Manufacturing Process) In this process, the control unit 40 manufactures a mixed liquid using the mixed liquid manufacturing device 10. At this time, the control unit 40 mixes the first liquid and the second liquid in the mixing chamber 15 and the discharge path 17 without discharging them from the discharge port 18 at the lower end of the discharge path 17 below the mixing chamber 15. For this purpose, the mixing chamber 15 is communicated with the ejector 31 as a suction source, and the air pressure in the mixing chamber 15 is set to a predetermined negative pressure value lower than the external air pressure.

[0036] Specifically, as shown in FIG. 2, the control unit 40 first opens the air supply on-off valve 37 and passes a predetermined amount of current through the suction pressure adjustment valve 38 to communicate the air source 35 with the ejector 31 and supply a predetermined amount of air to the ejector 31. As a result, the ejector 31 generates a suction force. Further, the control unit 40 opens the suction valve 33. As a result, the air in the mixing chamber 15 is sucked by the ejector 31 through the suction pipe 32 and the suction port 30 as indicated by the arrow 300 in FIG. 2. Thereby, the air pressure in the mixing chamber 15 becomes a predetermined negative pressure value lower than the outside air pressure. Note that the suction valve 33 may not be used when the suction source is the ejector 31. Note that when a suction pump is used as the suction source, it is preferable to provide the suction valve 33.

[0037] Next, the control unit 40 opens the first valve 23 to communicate the first liquid supply source 21 with the first liquid injection port 20. Thereby, the first liquid 401 is injected into the mixing chamber 15 from the first liquid supply source 21 through the first pipe 22 and the first liquid injection port 20. The injection amount of the first liquid 401 is, for example, 1.2 ml.

[0038] At this time, since the air pressure in the mixing chamber 15 is at a predetermined negative pressure value, the first liquid 401 injected into the mixing chamber 15 is retained at the upper part (upper end) of the discharge path 17 without reaching, for example, the discharge path 17 below the mixing chamber 15 and is stored in the mixing chamber 15. Note that since the air pressure in the mixing chamber 15 is at a predetermined negative pressure value, when the first liquid 401 is injected into the mixing chamber 15 and stored in the mixing chamber 15, outside air is not sucked into the mixing chamber 15 from the discharge port 18.

[0039] Next, as shown in FIG. 3, the control unit 40 closes the first valve 23 and opens the second valve 28 to communicate the second liquid supply source 26 with the second liquid injection port 25. As a result, the injection of the first liquid 401 through the first pipe 22 and the first liquid injection port 20 stops, and the second liquid 402 is injected into the mixing chamber 15 from the second liquid supply source 26 through the second pipe 27 and the second liquid injection port 25. The injection amount of the second liquid 402 is, for example, 0.3 ml. Thereby, in the mixing chamber 15 and the discharge path 17, the first liquid 401 and the second liquid 402 are mixed to produce a mixed liquid 403.

[0040] At this time, since the air pressure in the mixing chamber 15 has reached a predetermined negative pressure value, the mixed liquid 403 produced in the mixing chamber 15 and the discharge path 17 reaches the lower part (the discharge port 18 at the lower end) of the discharge path 17 below the mixing chamber 15, but is not discharged from the discharge port 18 and is retained at the discharge port 18 and stored in the mixing chamber 15 and the discharge path 17.

[0041] Also, in the mixing chamber 15, a part of the produced mixed liquid 403 vaporizes to become a gas. This gas is sucked by the ejector 31 through the suction port 30 and the suction pipe 32, sent to the wet scrubber 70 shown in FIG. 1 through the exhaust pipe 39, and processed by the wet scrubber 70.

[0042] (Discharge step) Next, the control unit 40 raises the air pressure in the mixing chamber 15 above a predetermined negative pressure value. That is, it approaches the external air pressure. Thereby, the control unit 40 discharges all the mixed liquid 403 in the mixing chamber 15 and the discharge path 17 from the discharge port 18 at the lower end of the discharge path 17. Note that the mixed liquid 403 may be discharged by setting the mixing chamber 15 to the external air pressure.

[0043] Specifically, as shown in FIG. 4, the control unit 40 closes the second valve 28 and closes the air supply on-off valve 37. As a result, the injection of the second liquid 402 through the second pipe 27 and the second liquid injection port 25 is stopped, and the communication between the air source 35 and the ejector 31 is blocked. Consequently, the suction of the gas in the mixing chamber 15 by the ejector 31 is stopped, and outside air enters the exhaust pipe 39, causing the pressure inside the exhaust pipe 39 to become the outside air pressure. For this reason, the suction pipe 32 communicated with the exhaust pipe 39 via the ejector 31, as well as the suction port 30 and the mixing chamber 15 communicated with the suction pipe 32, also become the outside air pressure at a pressure higher than a predetermined negative pressure value. That is, the mixed liquid 403 may be discharged by sucking outside air from the exhaust pipe 39 to make the pressure inside the mixing chamber 15 the outside air pressure.

[0044] As a result, all of the mixed liquid 403 in the mixing chamber 15 and the discharge path 17 is discharged from the discharge port 18 of the discharge path 17 below the mixing chamber 15 toward the wafer 100 held on the holding table 53 of the cleaning tank unit 50. Then, the discharged mixed liquid 403 is accumulated on the surface of the wafer 100 by surface tension. In this way, a layer of the mixed liquid 403 is formed on the surface of the wafer 100. The surface of the wafer 100 is cleaned by this layer of the mixed liquid 403. In the case where the air supply on-off valve 37 is not provided, the pressure inside the mixing chamber 15 may be made higher than a predetermined negative pressure value by reducing the amount of air supplied to the ejector by the suction pressure adjustment valve 38. Note that the mixed liquid 403 may be discharged while rotating the holding table 53, for example, at 100 rpm to clean the wafer 100.

[0045] Next, as shown in FIG. 5, the control unit 40 controls the motor 55 in the cleaning tank unit 50 to rotate the spindle 56 and the holding table 53 as indicated by the arrow 501. As a result, the wafer 100 held by the holding table 53 is rotated, and the mixed liquid 403 that had formed a layer on the surface of the wafer 100 is removed from the wafer 100 and drops to the bottom 52 of the cleaning tank 51 of the cleaning tank unit 50. The dropped mixed liquid 403 is discharged through the drain port 59 as indicated by the arrow 502.

[0046] As described above, in the present embodiment, when cleaning the wafer 100, the first liquid 401 and the second liquid 402 are mixed in the mixed liquid manufacturing apparatus 10 to manufacture the mixed liquid 403, and the manufactured mixed liquid 403 is discharged onto the wafer 100. Then, when manufacturing the mixed liquid 403, the air pressure in the mixing chamber 15 is set to a predetermined negative pressure value lower than the outside air pressure by using the ejector 31 as a suction source, so that the first liquid 401, the second liquid 402, and the mixed liquid 403 do not leak from the discharge port 18 at the lower end of the discharge path 17 below the mixing chamber 15.

[0047] Also, in the present embodiment, when cleaning the wafer 100, by raising the air pressure in the mixing chamber 15 above the predetermined negative pressure value, all the mixed liquid 403 in the mixing chamber 15 and the discharge path 17 is discharged from the discharge port 18 at the lower end of the discharge path 17 toward the wafer 100.

[0048] Therefore, in the present embodiment, it is not necessary to provide a valve (for example, a discharge valve for discharging the mixed liquid 403) with which the mixed liquid 403 comes into contact in the discharge path 17 communicating with the mixing chamber 15 in which the mixed liquid 403 is stored. For this reason, when discharging the mixed liquid 403, it is possible to prevent the mixed liquid 403 from remaining in the discharge path 17 communicating with the mixing chamber 15.

[0049] In this embodiment, in the discharging step of discharging the liquid mixture 403 in the mixing chamber 15 and the discharge path 17 from the discharge port 18 of the discharge path 17, the communication between the air source 35 and the ejector 31 is blocked, so that the function of the ejector 31 as a suction source is stopped, and the air pressure in the mixing chamber 15 is set to the external air pressure. Thereby, the liquid mixture 403 is discharged from the discharge port 18. Further, the air pressure in the mixing chamber 15 may be increased to a pressure at which the liquid mixture 403 is discharged from the discharge port 18, higher than the above-described predetermined negative pressure value.

[0050] For this purpose, in the discharging step, the control unit 40 controls, for example, the suction pressure adjustment valve 38 to reduce the amount of air sent from the air source 35 to the ejector 31, thereby reducing the suction pressure of the air in the mixing chamber 15 by the ejector 31, and setting the air pressure in the mixing chamber 15 to a value higher than the predetermined negative pressure value and lower than the external air pressure. Even when the air pressure in the mixing chamber 15 is lower than the external air pressure, it is possible to discharge the liquid mixture 403 from the discharge port 18 of the discharge path 17 by utilizing the self-weight of the liquid mixture 403.

[0051] In this configuration, in the discharging step, by adjusting the amount of air sent from the air source 35 to the ejector 31, the air pressure in the mixing chamber 15 can be adjusted relatively finely. Therefore, it is possible to control the amount of the liquid mixture 403 discharged from the discharge port 18 of the discharge path 17.

[0052] Further, the wafer cleaning apparatus 1 may have a liquid mixture manufacturing apparatus 80 as shown in FIG. 6 instead of the liquid mixture manufacturing apparatus 10. The liquid mixture manufacturing apparatus 80 shown in FIG. 6 has a switching valve 45 in the first air pipe 36 instead of the air supply on-off valve 37 in the configuration of the liquid mixture manufacturing apparatus 10 shown in FIG. 1. Further, a second air pipe 46 connecting these is provided between the switching valve 45 and the suction pipe 32. The switching valve 45 can supply the air from the air source 35 to the ejector 31 via the first air pipe 36, or supply it to the suction port 30 via the second air pipe 46 and the suction pipe 32.

[0053] In this configuration, in the mixed solution manufacturing process, the control unit 40 controls the switching valve 45 to supply air from the air source 35 to the ejector 31 via the first air pipe 36. On the other hand, in the discharging process, as shown in FIG. 6, the control unit 40 closes the suction valve 33 and controls the switching valve 45 to supply air from the air source 35 to the suction port 30 via the second air pipe 46 and the suction pipe 32 as indicated by the arrow 301 in FIG. 6. As a result, in the discharging process, air is sent into the mixing chamber 15, and the air pressure in the mixing chamber 15 becomes higher than a predetermined negative pressure value, for example, a positive pressure higher than the outside air pressure. As a result, the mixed solution 403 is discharged from the discharge port 18. In this configuration, by setting the air pressure in the mixing chamber 15 to a positive pressure, the discharge rate of the mixed solution 403 can be increased.

[0054] Further, as shown in FIG. 1, the control unit 40 includes a first control unit 41 and a second control unit 42. Then, when injecting the first liquid 401 into the mixing chamber 15 in the mixed solution manufacturing process (see FIG. 2), the first control unit 41 of the control unit 40 controls the suction pressure adjustment valve 38 to adjust the suction pressure of the air in the mixing chamber 15 by the ejector 31, so that the air pressure in the mixing chamber 15 may be set to a first negative pressure value lower than the outside air pressure. This first negative pressure value is an example of the predetermined negative pressure value described above.

[0055] Also, when injecting the second liquid 402 into the mixing chamber 15 in addition to the first liquid 401 (see FIG. 3), the second control unit 42 of the control unit 40 controls the suction pressure adjustment valve 38 to adjust the suction pressure of the air in the mixing chamber 15 by the ejector 31, so that the air pressure in the mixing chamber 15 may be set to a second negative pressure value lower than the outside air pressure. Here, the second negative pressure value is a value larger in the negative pressure direction than the first negative pressure value (that is, an air pressure value lower than the first negative pressure value), and is an example of the predetermined negative pressure value described above.

[0056] By performing the control by the first control unit 41 and the second control unit 42 in this way, more mixed solution 403 can be manufactured in the mixing chamber 15. Therefore, in the wafer cleaning apparatus 1, it becomes easy to clean a wafer 100 larger than half an inch.

[0057] In this embodiment, in the mixed solution production process, the first liquid 401 and the second liquid 402 are mixed in the mixing chamber 15 and the discharge path 17 to produce a mixed solution 403, and the mixed solution 403 is stored in the mixing chamber 15 and the discharge path 17. In this regard, the control unit 40 may, for example, adjust the air pressure in the mixing chamber 15 to mix the first liquid 401 and the second liquid 402 only in the mixing chamber 15 to produce the mixed solution 403, and store the mixed solution 403 only in the mixing chamber 15.

[0058] Further, as shown in FIG. 1, the control unit 40 includes a third control unit 43. In the mixed solution production process, the third control unit 43 sucks the gas in the mixing chamber 15 from the suction port 30 and sucks air into the mixing chamber 15 from the discharge port 18 at the lower end of the discharge path 17, and can control the suction pressure adjustment valve 38 so as to mix the first liquid 401 and the second liquid 402.

[0059] That is, when injecting the second liquid 402 into the mixing chamber 15 in the mixed solution production process (see FIG. 3), for example, the third control unit 43 controls the suction pressure adjustment valve 38 to adjust the suction pressure of the air in the mixing chamber 15 by the ejector 31, so that the air pressure in the mixing chamber 15 is set to a third negative pressure value lower than the external air pressure. This third negative pressure value is such that external air is sucked into the mixing chamber 15 from the discharge port 18 at the lower end of the discharge path 17. Thereby, in the mixing chamber 15, the first liquid 401 and the second liquid 402 can be satisfactorily mixed using the air sucked from the outside, so that the mixed solution 403 can be satisfactorily produced.

[0060] Note that the control by such a third control unit 43 is preferably used, for example, when the toxicity of the mixed solution is smaller than that of a piranha solution or the like, when the first liquid and the second liquid are difficult to mix, and / or when the mixed solution is likely to dry.

[0061] In addition, in the present embodiment, the discharge path 17 is provided so as to penetrate the bottom plate 14 of the mixing container 11. In this regard, as the discharge path 17, a pipe that penetrates the bottom plate 14 and protrudes downward from the bottom plate 14 may be provided. In this case, the lower end of the pipe serves as the discharge port 18 from which the mixed liquid 403 is discharged.

[0062] In addition, in the present embodiment, the first liquid and the second liquid are mixed to produce a mixed liquid. In this regard, in the mixed liquid production apparatus 10, the mixed liquid may be produced by mixing at least two liquids. Therefore, the mixed liquid production apparatus 10 may be configured to produce a mixed liquid by mixing three or more types of liquids.

Explanation of Reference Numerals

[0063] 1: Wafer cleaning apparatus, 10: Mixed liquid production apparatus, 80: Mixed liquid production apparatus, 11: Mixing container, 12: Side plate, 13: Top plate, 14: Bottom plate, 15: Mixing chamber, 17: Discharge path, 18: Discharge port, 20: First liquid inlet, 21: First liquid supply source, 22: First pipe, 23: First valve, 25: Second liquid inlet, 26: Second liquid supply source, 27: Second pipe, 28: Second valve, 30: Suction port, 31: Ejector, 32: Suction pipe, 33: Suction valve, 35: Air source, 36: First air pipe, 37: Air supply on-off valve, 38: Suction pressure adjustment valve, 39: Exhaust pipe, 40: Control unit, 41: First control unit, 42: Second control unit, 43: Third control unit, 45: Switching valve, 46: Second air pipe, 50: Cleaning tank unit, 51: Cleaning tank, 52: Bottom, 53: Holding table, 54: Holding surface, 55: Motor, 56: Spindle, 57: Rotating part, 58: Sealing member, 59: Drain port, 70: Wet scrubber, 71: Housing, 72: Shower nozzle, 73: Water source, 74: Decontamination filter, 75: Exhaust port, 100: Wafer, 200: Water droplet, 401: First liquid, 402: Second liquid, 403: Mixed liquid

Claims

1. A mixed - liquid manufacturing apparatus for manufacturing a mixed liquid by mixing at least two liquids, comprising: a mixing chamber surrounded by a bottom plate, side plates, and a top plate; a first - liquid injection port for injecting a first liquid into the mixing chamber; a second - liquid injection port for injecting a second liquid into the mixing chamber; a discharge path penetrating the bottom plate for discharging the mixed liquid obtained by mixing the first liquid and the second liquid from the mixing chamber; a suction port for communicating the inside of the mixing chamber with a suction source to suck the gas inside the mixing chamber; a suction - pressure adjustment valve for adjusting the suction pressure when sucking the gas from the suction port; and a control unit, wherein the control unit: communicates the mixing chamber with the suction source to set the air pressure in the mixing chamber to a predetermined negative pressure value lower than the atmospheric pressure in order to mix the first liquid and the second liquid without discharging them from the lower end of the discharge path; increases the air pressure in the mixing chamber above the predetermined negative pressure value to discharge all the mixed liquid in the mixing chamber and the discharge path from the lower end of the discharge path; and the control unit: is provided with a third control unit that controls the suction - pressure adjustment valve so as to suck the gas inside the mixing chamber from the suction port and suck air into the mixing chamber from the lower end of the discharge path to mix the first liquid and the second liquid. Mixed - liquid manufacturing apparatus.

2. The suction source is an ejector, and the suction - pressure adjustment valve adjusts the suction pressure by adjusting the amount of air supplied to the ejector. The mixed - liquid manufacturing apparatus according to Claim 1.

3. The control unit: includes a first control unit that sets the air pressure in the mixing chamber to a first negative pressure value when injecting the first liquid into the mixing chamber; and a second control unit that sets the air pressure in the mixing chamber to a second negative pressure value greater in the negative - pressure direction than the first negative pressure value when injecting the second liquid into the mixing chamber in addition to the first liquid. The mixed - liquid manufacturing apparatus according to Claim 1.

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