JP2004057873A - Mixing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mix a plurality of fluids having a largely different mixing ratio to a uniform concentration. <P>SOLUTION: A mixing apparatus mixes two pressurized fluids by a mixing unit 16. The mixing unit 16 is constituted of a unit body 60, a first mixing chamber 62, a second mixing chamber 64, a throttle hole 66, an inflow pipe 68, an outflow pipe 70 and a throttle pipe 25. The fluid accelerated by the throttle pipe 66 is decelerated in its flow velocity in the second mixing chamber 64 and, the flow thereof is changed by the end part of the outflow pipe 70. Therefore, the fluid passes through the inner space of the second mixing chamber 64 having a large flow channel area in a turbulent state to be discharged to a discharge pipeline 52 from a small-diameter outflow passage 70a. The chemical liquid and pure water mixed with each other in the first mixing chamber 62 are uniformly mixed so as to become a uniform and constant concentration in the process passed through the first mixing chamber 62, the throttle valve 66 and the second mixing chamber 64 to be stably supplied to the discharge pipeline 52. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mixing apparatus that supplies a mixed liquid used in a flat panel display manufacturing process such as a semiconductor or a liquid crystal by mixing a plurality of chemical solutions having different components, for example.
[0002]
[Prior art]
Hereinafter, a mixing device for mixing pure water and a chemical solution will be described as an example of a mixing device for mixing two types of liquids.
[0003]
2. Description of the Related Art Conventionally, as a mixing device for mixing two kinds of chemical solutions having different components, for example, there is a mixing device described in JP-A-2000-74718. In this gazette, an undiluted chemical solution is weighed and measured in a measuring tank, then the measured chemical solution is dropped into a mixing tank, mixed, diluted with pure water to a predetermined concentration, and then the mixed and diluted chemical liquid is stored. It is configured to be dropped into a tank, heated to a predetermined temperature, and supplied to a semiconductor manufacturing apparatus.
[0004]
In this type of mixing apparatus, the measurement of the chemical solution and the amount of dilution with pure water are managed by measuring (detecting) the liquid level in each tank.
[0005]
In addition, a flow meter for measuring the respective flow rates is provided in a supply pipe for supplying the chemical solution and the pure water, and the flow rate is measured using the flow meter while controlling the valve opening of the flow control valve to control the chemical solution and the pure water. It is also considered to adjust the mixing ratio with water.
[0006]
[Problems to be solved by the invention]
However, in the conventional mixing apparatus configured as described above, the number of tanks such as a measuring tank, a mixing tank, and a supply tank is large, and the capacity of each tank is large. Therefore, it is difficult to reduce the size of the apparatus.
[0007]
In addition, since a liquid level sensor is used for weighing the chemical solution, weighing the pure water used for dilution, and detecting a request for replenishing the storage tank with the chemical solution, the liquid may foam in the tank or the liquid surface may undulate. Then, the liquid level sensor malfunctions, and it becomes impossible to mix the chemical liquid at a mixing ratio of a predetermined concentration. In addition, since the liquid level sensors provided in each tank are expensive, it has been difficult to reduce the manufacturing cost of the apparatus.
[0008]
Further, in the device for controlling the opening degree of the flow control valve described above, when the mixing ratio of the chemical liquid and the pure water is, for example, 1:99, and the liquid volume of the generated mixed liquid is 20 L (liter), Is 200 mL (milliliter), whereas the supply of pure water is 19800 mL. In the case where the mixing ratio of the two liquids is greatly different, for example, the flow rate is controlled so that the chemical liquid is supplied at a very small flow rate by controlling the valve opening of the flow control valve while measuring the flow rate using a flow meter. It was difficult to adjust, and the mixing ratio of the liquid mixed at a constant ratio was not stable.
[0009]
In addition, when mixing with pure water while adjusting the flow rate of the chemical solution to a very small flow rate, if a concentrated chemical solution (raw solution) is dropped into the supply tank, it does not mix sufficiently with the chemical solution previously stored in the supply tank, and The chemical solution must be supplied in small increments as much as possible because the undiluted solution falls into the chemical solution in the supply tank without being diffused. Therefore, there is a possibility that a high-concentration chemical solution is supplied.
[0010]
Therefore, an object of the present invention is to provide a mixing device that solves the above problems.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following features.
According to the present invention, a plurality of fluid supply paths that individually supply different types of fluids, a fluid supply unit that supplies a fluid flowing through the plurality of fluid supply paths by pressurizing the fluid to a predetermined pressure, and a fluid supply unit that is pressurized. A mixing device for mixing a plurality of fluids, the mixing device comprising: a first mixing chamber in which the plurality of fluids supplied from the plurality of fluid supply paths are mixed; and a first mixing chamber. A throttle formed to have a smaller diameter than that of the first mixing chamber to increase the flow velocity of the fluid mixed in the first mixing chamber; and a throttle formed to have a larger diameter than the throttle to reduce the flow velocity of the fluid discharged from the throttle to change to a turbulent flow. And a second mixing chamber, whereby a plurality of fluids can be uniformly mixed by a turbulent flow in the course of flow, and a mixed fluid having a constant concentration can be stably supplied.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a schematic configuration of an embodiment of the mixing apparatus according to the present invention.
As shown in FIG. 1, for example, the mixing device 10 includes a 50% hydrofluoric acid (chemical solution) supplied via a chemical solution supply path 12 and pure water supplied via a pure water supply path 14. Are mixed by a mixing unit (mixing means) 16 and supplied to a wafer (not shown) in a semiconductor manufacturing line. In addition, hydrofluoric acid is an aqueous solution of hydrogen fluoride (hydrogen fluoride), and is hereinafter referred to as “chemical solution (HF solution)”.
[0013]
The chemical supply path 12 is provided with a storage tank 22 as pump means (fluid supply means) for supplying the stored chemical at the pressure of nitrogen gas. The storage tank 22 is in communication with the chemical supply pipe 18 and the nitrogen gas supply pipe 20. The chemical solution discharge pipe 24 drawn from the bottom of the storage tank 22 is connected to the mixing unit 16 via a throttle pipe 25 for reducing the flow rate of the chemical solution to a very small flow rate. An air-driven open / close valve 43 and a check valve (backflow prevention valve) 44 provided upstream of the open / close valve 43 are disposed in the chemical solution discharge pipe 24.
[0014]
The nitrogen gas supply pipe 20 has a pressure reducing valve 26 for reducing the chemical solution supply pressure to a predetermined pressure, a mass flow meter 27 for measuring a mass flow rate of the nitrogen gas, a gas filter 28 for removing fine particles in the nitrogen gas, and a nitrogen gas. An air-driven flow control valve 30 for controlling the flow rate of gas is provided. The chemical supply pipe 18 is provided with an ultrasonic vortex flowmeter 32 for measuring the flow rate of the chemical, a check valve (backflow prevention valve) 33, and an air-driven open / close valve 34 for controlling the supply of the chemical. Have been.
[0015]
The ultrasonic vortex flow meter 32 measures the flow rate of the chemical liquid (HF liquid) supplied from the chemical liquid supply pipe 18 and transmits an analog signal proportional to the flow rate from the transmitter 32a to the control circuit 40. . Then, the control circuit 40 controls the opening and closing of the on-off valve 34 based on the flow rate measurement value obtained from the analog signal.
[0016]
The mass flow meter 27 measures the flow rate of the nitrogen gas supplied from the nitrogen gas supply pipe 20, and transmits an analog signal having a cycle proportional to the flow rate to the control circuit 40. Then, the control circuit 40 controls the valve opening of the flow control valve 30 so that the analog signal is stabilized at the set value.
[0017]
The storage tank 22 is for stably supplying a chemical solution (HF solution) by temporarily storing the chemical solution (HF solution) supplied from the chemical solution supply pipe 18. Above the storage tank 22, a gas vent pipe 35 and a liquid level sensor 38 for measuring pressure are provided. The gas vent line 35 is provided with a check valve (backflow prevention valve) 36 and an air-driven relief valve 37. In addition, the relief valve 37 is opened at the time of injecting the chemical, and exhausts the nitrogen gas remaining in the storage tank 22 to the outside to reduce the load at the time of injecting the chemical.
[0018]
The detection signal from the liquid level sensor 38 is input to the control circuit 40, and the control circuit 40 manages the liquid level (liquid level) of the storage tank 22.
[0019]
The pure water supply path 14 includes a pump (fluid supply means) 46 for supplying pure water to a pure water supply pipe 45, an ultrasonic vortex flow meter 48 for measuring the flow rate of pure water, A flow control valve 50 for adjusting the supply amount is provided. The ultrasonic flowmeter 48 measures the flow rate of pure water supplied from the pure water supply path 14 and transmits an analog signal having a cycle proportional to the flow rate from the transmitter 48a to the control circuit 40.
[0020]
Then, the control circuit 40 outputs a control signal to the electropneumatic regulator 49 based on the flow rate measurement value obtained from the analog signal. The electropneumatic regulator 49 is provided in an air pressure supply pipe 49a connected to the actuator section 50a of the flow control valve 50, and is supplied to the actuator section 50a of the flow control valve 50 based on a control signal from the control circuit 40. Adjust air pressure. As a result, the flow control valve 50 drives the actuator section 50a by the air pressure supplied from the electropneumatic regulator 49, and controls the valve opening by driving the actuator section 50a to adjust the flow rate.
[0021]
The open / close valves 34 and 43 and the relief valve 37 are configured with an air-driven normally closed valve structure, and open with air (compressed air) supplied from an air supply circuit 39. Further, the air supply circuit 39 supplies compressed air from an air source (compressor or the like) 41 to the air pipes 30 a, 34 a, 43 a, and 37 a communicating with the flow control valve 30, the on-off valves 34 and 43, and the relief valve 37. (Not shown) is provided to selectively supply the pressure.
[0022]
Therefore, the air supply circuit 39 turns on or off the compressed air to be supplied to the air pipelines 30a, 34a, 43a, and 37a based on a control signal from the control circuit 40, and adjusts the valve opening of the flow control valve 30. Then, the on / off valves 34 and 43 or the relief valve 37 are opened or closed.
[0023]
The chemical solution supply line 18 and the pure water supply line 45 are made of a material such as perfluoroalkoxy copolymer (PFA resin) or polyvinylidene fluoride (PVDF resin), which has very little elution of impurities and generation of fine particles. Is formed.
[0024]
At the start of the fluid supply, the memory of the control circuit 40 includes an on-off valve 43 disposed on the chemical solution discharge line 24 and a flow control valve 30 and an on-off valve 43 disposed on the nitrogen gas supply line 20, and pure water. A control program (control means) for opening the flow control valve 50 arranged in the supply line 45 is stored.
[0025]
In addition, when the fluid supply is stopped, the memory of the control circuit 40 includes an on-off valve 43 disposed on the chemical solution discharge pipe 24, a flow control valve 30 disposed on the nitrogen gas supply pipe 20, and a pure water supply pipe 45. A control program (control means) for closing the arranged flow regulating valve 50 is stored.
[0026]
FIG. 2 is an enlarged longitudinal sectional view showing the configuration of the mixing unit 16. FIG. 3 is a longitudinal sectional view taken along line AA in FIG.
As shown in FIGS. 2 and 3, the mixing unit 16 includes a unit main body 60 made of tetrafluoroethylene resin (PTFE resin) having excellent chemical resistance, and a first mixing unit opened at one end of the unit main body 60. A second mixing chamber 64 opening at the other end of the unit main body 60, a small-diameter throttle hole 66 communicating between the first mixing chamber 62 and the second mixing chamber 64, An inflow pipe 68 press-fitted (or bonded) into the opening of the mixing chamber 62, an outflow pipe 70 press-fitted (or bonded) into the opening of the second mixing chamber 64, and inserted into the first mixing chamber 62 from above. And a constriction tube 25.
[0027]
The first mixing chamber 62, the second mixing chamber 64, and the throttle hole 66 are arranged in series on the same axis, and the inflow path 68a of the inflow pipe 68, the throttling hole 66, and the outflow path 70a of the outflow pipe 70 are also provided. It is arranged on the center line of the unit main body 60.
[0028]
In this embodiment, assuming that the inside diameter d1 of the inflow passage 68a, the inside diameter d2 of the first mixing chamber 62, the inside diameter d3 of the throttle hole 66, the inside diameter d4 of the second mixing chamber 64, and the inside diameter d5 of the outflow passage 70a, Is set such that d2 (= d4)> d1 (= d5)> d3.
[0029]
The inflow passage 68a communicates with the pure water supply pipeline 45, and the outflow passage 70a communicates with the discharge pipeline 52 communicated downstream of the mixing unit 16. The throttle pipe 25 has a small-diameter hole 25a penetrating like a needle, and supplies the chemical supplied from the chemical discharge pipe 24 to the first mixing chamber 62.
[0030]
Further, the tip of the throttle pipe 25 projects to the center of the first mixing chamber 62, and the chemical at a small flow rate discharged from the hole 25 a is pressurized to a predetermined pressure by the nitrogen gas pressure in the storage tank 22. The water is pushed out and mixed with the nitrogen gas pressure at the center of the pure water flowing from the inflow passage 68a (in a region where the flow velocity is high).
[0031]
Therefore, the flow of the pure water discharged from the inflow passage 68a to the center of the first mixing chamber 62 is pressurized to a predetermined pressure by the pump 46, and collides with the tip of the throttle pipe 25 at a high flow velocity to generate a turbulent flow. While being in a state, it is mixed with the chemical solution discharged from the throttle tube 25.
[0032]
Conically inclined tapered portions 72 and 74 are formed at the entrance and exit of the throttle hole 66. Accordingly, the fluid mixed in the first mixing chamber 62 is guided by the tapered portion 72 and flows into the small-diameter throttle hole 66 to accelerate the flow velocity.
[0033]
Further, the fluid that has passed through the throttle hole 66 is guided by the tapered portion 74 and diffuses into the second mixing chamber 64 to mix the chemical solution and pure water so as to have a uniform mixing ratio. Therefore, the fluid does not stay due to the tapered portions 72 and 74 provided at the inlet and the outlet of the throttle hole 66, and the high-concentration regions are partially formed in the first mixing chamber 62 and the second mixing chamber 64. Formation is prevented.
[0034]
As described above, the fluid accelerated by the throttle hole 66 has its flow velocity reduced in the second mixing chamber 64 and the flow changes at the end of the outflow pipe 70, so that the second mixing chamber 64 having a large channel area is used. Is discharged in a turbulent state through the small outflow passage 70 a to the discharge pipe 52.
[0035]
Therefore, the chemical and pure water mixed in the first mixing chamber 62 are mixed and discharged to a uniform and uniform concentration while passing through the first mixing chamber 62, the throttle hole 66, and the second mixing chamber 64. It is supplied stably to the pipeline 52. In particular, even when the mixing ratio between the small flow rate chemical solution and the large flow rate water input is very different, such as 1:99, the two liquids mixed in the first mixing chamber 62 are mixed in the first mixing chamber 62 and the throttle hole. 66, it becomes possible to mix to a uniform concentration in the process of passing through the second mixing chamber 64.
[0036]
Further, the mixing unit 16 has a configuration in which the first mixing chamber 62, the second mixing chamber 64, and the throttle hole 66 are arranged in series on the same axis, so that processing is easy. The first mixing chamber 62 is cut by a drill from one end, the first mixing chamber 62 is cut by a center drill from the other end of the unit body 60, and the drawing hole 66 is cut by a relatively small amount. The unit main body 60 can be manufactured with man-hours. Therefore, the manufacturing cost of the mixing unit 16 can be reduced.
[0037]
Further, the unit main body 60 may be processed by a cutting process using a drill as described above, or may be integrally formed using a mold. In this case, it is possible to reduce costs due to mass production effects.
[0038]
Here, a modified example will be described.
FIG. 4 is an enlarged longitudinal sectional view illustrating the configuration of Modification Example 1 of the mixing unit 16. FIG. 5 is a longitudinal sectional view taken along line BB in FIG. 4 and 5, the same parts as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.
As shown in FIGS. 4 and 5, in the mixing unit 16, a vortex generator 80 is suspended in a second mixing chamber 64. The vortex generator 80 is provided so as to be located between the throttle hole 66 and the outflow passage 70a.
[0039]
Therefore, the fluid discharged from the throttle hole 66 is accelerated in the process of passing through the throttle hole 66, and collides with the vortex generator 80 in the second mixing chamber 64 and bypasses to the downstream side of the vortex generator 80. It becomes a flow that does. Due to such a change in the direction of the flow, a turbulent state is created downstream of the vortex generator 80, and a Karman vortex is generated further downstream. As a result, the chemical solution and pure water mixed in the first mixing chamber 62 are mixed to a uniform and uniform concentration while passing through the first mixing chamber 62, the throttle hole 66, and the second mixing chamber 64. It is stably supplied to the discharge pipeline 52.
[0040]
FIG. 6 is an enlarged longitudinal sectional view showing the configuration of Modification 2 of the mixing unit 16. In FIG. 6, the same parts as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.
As shown in FIG. 6, the mixing unit 16 may have a configuration in which vertical walls 82 and 84 are provided instead of the tapered portions 72 and 74 at the entrance and the exit of the throttle hole 66.
[0041]
In the second modification, the flow of the pure water discharged from the inflow passage 68a to the center of the first mixing chamber 62 collides with the tip of the throttle pipe 25 at a high flow rate, and forms a turbulent flow from the throttle pipe 25. After being mixed with the discharged chemical, the liquid collides with the wall portion 82 to generate a complicated flow (vortex) to mix the two liquids at a uniform concentration.
[0042]
Further, the flow rate of the fluid accelerated by the throttle hole 66 is reduced in the second mixing chamber 64 and the flow is changed by the end of the outflow pipe 70. The gas passes through the space in a turbulent state and is discharged from the small-diameter outflow passage 70a to the discharge pipe 52.
[0043]
As described above, the two types of fluids are mixed in the first mixing chamber 62 and further mixed in the second mixing chamber 64, so that the first mixing chamber 62, the throttle hole 66, and the second mixing chamber 64 Are mixed stepwise into a uniform and uniform concentration and are stably supplied to the discharge pipeline 52.
[0044]
FIG. 7 is a longitudinal sectional view showing the configuration of Modification 3 of the mixing unit 16 in an enlarged manner. In FIG. 7, the same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
As shown in FIG. 7, the mixing unit 16 has a first mixing chamber 62 formed at one end of the unit main body 60, and an insertion hole 60a for inserting a cylindrical throttle member 90 at the other end of the unit main body 60. Is formed. The restricting member 90 has a restrictor hole 66 penetrating through a wall portion 90a at one end, and a second mixing chamber 64 formed at the other end. A seal member (O-ring) 92 for sealing the space between the aperture member 90 and the insertion hole 60a of the unit main body 60 is mounted on the outer periphery of the aperture member 90.
[0045]
Since the aperture member 90 is assembled to the unit main body 60, for example, by preparing a plurality of aperture members 90 having different inner diameters of the aperture holes 66, the inner diameter of the aperture holes 66 can be easily changed. .
[0046]
Further, by removing the aperture member 90 from the unit main body 60, it becomes possible to form a plurality of small holes in the wall portion 90a.
[0047]
In the present embodiment, an apparatus configured to mix two kinds of fluids by the mixing nozzle 16 is described as an example. However, the present invention is not limited to this. For example, two kinds of fluids are mixed in a tank and stirred. Needless to say, the present invention can also be applied to a mixing device configured to supply the mixture.
[0048]
Further, in the present embodiment, the case where hydrofluoric acid and pure water are mixed at a predetermined ratio has been described as an example, but the present invention can of course be applied to the case where other chemicals are mixed. .
[0049]
Further, in the present embodiment, a case where two kinds of liquids of hydrofluoric acid and pure water are mixed is described as an example, but the present invention is also applied to a case where two or more kinds of fluids having different components are mixed. Of course you can.
[0050]
In the present embodiment, a pump is used as the pure water supply means. However, the present invention is not limited to this. For example, a method using a height difference as the fluid supply means may be used.
[0051]
【The invention's effect】
As described above, according to the present invention, a plurality of fluid supply paths for individually supplying different types of fluids, a liquid supply means for supplying a fluid flowing through the plurality of fluid supply paths to a predetermined pressure, and a liquid supply path Mixing means for mixing the plurality of fluids pressurized by the means, wherein the mixing means comprises: a first mixing chamber in which the plurality of fluids supplied from the plurality of fluid supply paths are mixed. A throttle formed to have a smaller diameter than the first mixing chamber and increasing the flow velocity of the fluid mixed in the first mixing chamber; and a throttle formed to have a larger diameter than the throttle and reducing the flow velocity of the fluid discharged from the throttle. And a second mixing chamber that changes the fluid into a turbulent flow, so that a plurality of fluids can be uniformly mixed by the turbulent flow in the process of flowing, and the mixed fluid having a constant concentration can be stably supplied. Becomes possible. For example, when the mixing ratio is greatly different, such as 1:99, the process of passing the two liquids mixed in the first mixing chamber through the first mixing chamber, the throttle, and the second mixing chamber. It is possible to stably supply the mixture at a uniform and uniform concentration.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a schematic configuration of an embodiment of a mixing device according to the present invention.
FIG. 2 is an enlarged longitudinal sectional view showing a configuration of a mixing unit 16;
FIG. 3 is a vertical sectional view taken along line AA in FIG. 2;
FIG. 4 is an enlarged longitudinal sectional view illustrating a configuration of Modification Example 1 of a mixing unit 16;
FIG. 5 is a longitudinal sectional view taken along line BB in FIG.
FIG. 6 is an enlarged longitudinal sectional view illustrating a configuration of a modification 2 of the mixing unit 16;
FIG. 7 is an enlarged longitudinal sectional view illustrating a configuration of a modification 3 of the mixing unit 16.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Mixing device 12 Chemical supply path 14 Pure water supply path 16 Mixing unit 18 Chemical supply line 20 Nitrogen gas supply line 22 Storage tank 24 Chemical discharge line 27 Mass flow meter 30 Flow control valves 34, 37, 43 Open / close valve 30a , 34a, 37a, 34a Air lines 32, 48 Ultrasonic vortex flow meter 37 Relief valve 38 Liquid level sensor 39 Air supply circuit 40 Control circuit 41 Air source 44 Flow rate stabilizing unit 45 Pure water supply line 46 Pump 50 Flow rate adjustment Valve 60 Unit main body 62 First mixing chamber 64 Second mixing chamber 66 Throttle hole 68 Inflow pipe 70 Outflow pipe 72, 74 Taper section 80 Vortex generator 82, 84 Wall section 90 Throttle member

Claims (1)

A plurality of fluid supply paths for individually supplying different types of fluids,
Fluid supply means for supplying the fluid flowing through the plurality of fluid supply paths by pressurizing the fluid to a predetermined pressure,
Mixing means for mixing a plurality of fluids pressurized by the fluid supply means,
In a mixing device comprising:
The mixing means,
A first mixing chamber in which a plurality of fluids supplied from the plurality of fluid supply paths are mixed;
A throttle formed to have a smaller diameter than the first mixing chamber and increasing the flow velocity of the fluid mixed in the first mixing chamber;
A second mixing chamber formed to be larger in diameter than the throttle and for reducing the flow velocity of the fluid discharged from the throttle to change it into turbulent flow;
A mixing device comprising:

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