JP2000042390A - Liquid dilution device - Google Patents

Abstract

(57) [Problem] To provide an inexpensive liquid diluting device which can obtain a highly uniform diluent, can be easily miniaturized, and is inexpensive. SOLUTION: A pure water tank and a chemical solution tank are provided so as not to be affected by a fluctuation of a supply pressure of a factory, and a level of the pure water tank and the chemical solution tank is controlled to be constant, and an inlet portion of the aspirator is provided. To allow pure water from the pure water tank to pass through, and to the siphon section of the aspirator,
A liquid diluting device that allows the chemical solution from the chemical solution tank to pass through, and obtains a uniform diluent with high predetermined dilution accuracy from the outlet of the aspirator, and is easy to miniaturize and has good reproducibility. It is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inexpensive liquid diluting apparatus which can obtain a highly uniform diluent, can be easily miniaturized, and is inexpensive.

In particular, the present invention relates to an apparatus for mixing and diluting a liquid chemical (hydrofluoric acid, hydrochloric acid, ammonia, etc.) with ultrapure water, and the diluted aqueous solution is used for cleaning a silicon wafer in a semiconductor manufacturing apparatus. used.

[0003]

2. Description of the Related Art FIG. 4 is an explanatory view of the structure of a conventional example generally used in the prior art.
And the title of the invention, "Wet Processing Apparatus for Semiconductor Wafer", published on September 19, 1995.

In a diluent used in a semiconductor process, the volume of a chemical solution and the volume of a diluent are measured in a diluent tank 1 and a diluent tank, respectively, so that a diluent having a predetermined concentration can be accurately obtained. The liquid is measured in the liquid measuring tank 2 and is simultaneously sent to the storage tank 5 via pipes 3 and 4 for storage.

If the storage amount in the storage tank 5 is not sufficient, the above operation is repeated to secure the required storage amount in the storage tank 5.

[0006] As described above, by measuring in the measuring tanks 1 and 2 and mixing each time, a diluent having an accurate volume ratio can be obtained. From this storage tank 5, the required amount is transferred to another container by pressurized transfer and used for a predetermined operation.

[0007]

However, in such an apparatus, (1) a uniform diluent is not obtained. When the concentration in the storage tank 5 was examined, the concentration was different between the liquid in the upper part and the liquid in the lower part of the storage tank 5.

[0008] This is because the method of dropping and mixing a chemical solution and a diluting solution is
This is because the pipes 3 and 4 having the same diameter are flowing into the storage tank 5.

For example, to make a 10% concentration diluent,
Since the amount of the chemical solution only needs to be 1/10 of the diluent solution, even if the chemical solution and the diluent solution are dropped at the same time, one of the two solutions will always run out unless the flow rate ratio is set to 1:10.

[0010] Then, the state where only the remaining liquid is dropped finally exists. In the conventional system, the drop flow rate ratio is approximately 1: 1 so that the chemical solution is exhausted first.
That is, a thick liquid is generated in the first half of the dropping, and a thin liquid is generated in the second half of the dropping.

[0011] As a method of improving this heterogeneous mixing,
The diluent may be prepared by adjusting the flow rate during spontaneous dropping and mixing the two liquids simultaneously.

In order to produce such a uniform diluent with a specified dilution ratio with high accuracy, it is necessary to monitor the flow rate and adjust the flow rate. However, using a flow meter results in an expensive liquid diluting device.

In addition, it is considered that the stirring may be performed by using a stirrer when the concentration is not uniform. However, the diluent used in the semiconductor process causes a problem of particles, and the stirrer is used. I do not want to adopt as much as possible.

(2) The device becomes large. In the conventional apparatus, the measuring tanks 1 and 2 are always required. This volume can be as small as 100 cc or as large as 10 cc.
That is all. As the number of types of chemicals increases, measuring tanks are required for the number of types.

Further, a storage tank 5 is required, and the apparatus becomes large. In addition, if the number of times of weighing increases, the working time also increases (decrease in throughput) and the error increases. Therefore, the realistic number of times is at most two or three. (3) When installed in a factory, accuracy is low because it is greatly affected by pressure fluctuations in the factory that supplies pure water or hydrofluoric acid.

For this reason, it is generally considered that a method of once storing pure water and hydrofluoric acid supplied in a factory in a tank and mixing the two liquids by pressurizing with a pump or N2 can be adopted.

However, in this method, (1) even if a stirrer or the like is used when mixing the two liquids, the mixture is not sufficiently uniform, so that the dilution accuracy is low.

(2) Even if the pressure fluctuation of the pure water or the hydrofluoric acid line in the factory is adjusted by the pressure regulator, it cannot be adjusted completely, and the influence of the fluctuation appears. (3) The capacity of the tank is generally 10 to 20 l, which makes the equipment larger

The present invention solves this problem. The object of the present invention is to obtain a highly uniform diluent,
An object of the present invention is to provide an inexpensive liquid diluting device that can be easily miniaturized.

[0020]

In order to achieve this object, the present invention provides: (1) a first pure water supply in which one end is connected to a pure water supply pipe of a factory and pure water of a predetermined purity is supplied; In a liquid diluting apparatus including a pipe and a first chemical liquid supply pipe having one end connected to a chemical liquid supply pipe of a factory and supplied with a chemical liquid, pure water to which the other end of the first pure water supply pipe is connected A tank, a pressure application means connected to the pure water tank and applying pressure to the pure water, an internal pressure adjusting means for adjusting an internal pressure of the pure water tank, and a pure water tank for detecting a predetermined water level of the pure water tank A water level detecting means, a second pure water supply pipe having one end connected to the pure water tank and through which pure water from the pure water tank passes, and a chemical liquid tank to which the other end of the first chemical liquid supply pipe is connected. One end is connected to this chemical tank and the other end is large. An atmosphere release pipe released to the atmosphere, a chemical liquid tank water level maintaining means for maintaining a predetermined water level of the chemical liquid tank, a second chemical liquid supply pipe having one end connected to the chemical liquid tank and a chemical liquid from this chemical liquid tank passing therethrough, An aspirator having the other end of the second pure water supply pipe connected to an inlet and the other end of the second chemical liquid supply pipe connected to a siphon section; and an aspirator having the first and second pure water supply pipes. A stop valve provided in the middle and in the middle of the first and second chemical liquid supply pipes, the stop valve and the pressure application based on detection signals from the pure water tank water level detecting means and the chemical liquid tank water level detecting means. And a controller for controlling operation of the internal pressure adjusting means. (2) As the pressure application means, a pressure application pipe having one end connected to the pure water tank, a pressure application fluid applied to the other end of the pressure application pipe, and a pressure application pipe are provided in the middle of the pressure application pipe. The liquid diluting device according to claim 1, further comprising a stop valve. (3) The liquid diluting apparatus according to (2), wherein an inert gas is used as the pressure applying fluid. (4) The liquid diluting apparatus according to claim 3, wherein nitrogen is used as the inert gas. (5) As the internal pressure adjusting means, an adjusting unit having an internal pressure adjusting pipe having one end connected to the pure water tank and the other end being open to the atmosphere, and a stop valve and a needle valve provided in the middle of the internal pressure adjusting pipe. The liquid diluting apparatus according to any one of claims 1 to 4, further comprising: (6) The liquid diluting apparatus according to (4), wherein a plurality of the adjusting units are provided as the internal pressure adjusting means. (7) The liquid diluting device according to any one of claims 1 to 6, further comprising two liquid level sensors arranged at a predetermined interval as a pure water tank water level detecting means. (8) The liquid diluting device according to any one of claims 1 to 7, wherein the liquid diluting device has two liquid level sensors arranged at a predetermined interval as a chemical liquid tank water level detecting means. (9) The liquid diluting apparatus according to any one of claims 1 to 6, wherein a pressure sensor is used as the pure water tank water level detecting means. (10) The liquid diluting device according to any one of claims 1 to 9, further comprising a needle valve provided in the middle of the second pure water supply pipe. (11) The liquid diluting device according to any one of claims 1 to 10, further comprising a needle valve provided in the middle of the second chemical liquid supply pipe. (12) The liquid diluting device according to any one of claims 1 to 11, wherein a computer is used as the controller. (13) An output pipe having one end connected to the outlet of the aspirator and outputting a diluent having a predetermined concentration, a drain pipe having one end branched from the middle of the output pipe, and a downstream end of a branch point between the drain pipe and the drain pipe. 13. The liquid diluting device according to claim 1, further comprising a stop valve provided on the output pipe, and a stop valve provided on the way of the drain pipe. It is what constituted.

[0021]

In the above arrangement, first, the stop valve is opened, and pure water is injected into the pure water supply tank through the factory pure water supply pipe.

The pressure of pure water is adjusted to a constant value by a regulator. However, when the pressure of a supply source, ie, a pure water supply pipe of a factory, is large, the amount of pure water to be injected is not limited. Affected by fluctuations.

However, while the stop valve is open, the pressure adjustment stop valve is opened, and the pressure inside the pure water tank is released to make it constant (atmospheric pressure).

Since the change in the supply pressure of the pure water from the factory changes to the change in the liquid level rising speed of the pure water tank, it does not affect the flow rate of the pure water to the aspirator, which will be described later. .

(2) At a predetermined time, the pure water passes through the lower liquid level sensor and rises toward the upper liquid level sensor. When the pure water reaches the upper liquid level sensor at a predetermined time, the stop valve closes and the pure water supply stops.

While the stop valve is closed, it is naturally not affected by the pressure fluctuation of the factory pure water supply pipe. At the same time, the stop valve for pure water supply closes,
The stop valve of the pressure application means is opened, and the pressure by the pressure application fluid acts on the pure water in the pure water tank.

When the stop valve of the second pure water supply pipe opens, pure water flows out to the aspirator.

(3) On the other hand, the chemical liquid, for example, hydrofluoric acid is injected into the chemical liquid tank at a predetermined time by opening a stop valve of the chemical liquid supply pipe (hereinafter, description will be made by taking hydrofluoric acid as an example). ). At a predetermined time, the liquid is supplied to the upper liquid level sensor over the lower liquid level sensor.

At a predetermined time, when the hydrofluoric acid reaches the upper liquid level sensor, the stop valve closes. The stop valve of the second chemical supply pipe opens, and hydrofluoric acid flows to the aspirator.

(4) When pure water flows, hydrofluoric acid flows out by the suction force generated in the aspirator.

By accurately controlling the flow rate of pure water, the flow rate of hydrofluoric acid can be controlled automatically. This is the basic reason why highly accurate dilution can be performed.

(5) After a predetermined time, both pure water and hydrofluoric acid are flowing through the outlet of the aspirator. However, the dilution accuracy in the initial stage is poor.
Discharge to drain by opening stop valve.

At this time, the stop valve of the output pipe is closed. After a sufficient time has elapsed from a predetermined time, at a predetermined time, the stop valve of the output pipe is opened and the stop valve of the drain pipe is closed, so that the diluent can flow into the supply line.

(6) When the liquid level of the pure water tank becomes lower than the lower liquid level sensor, the stop valve of the pure water supply pipe is opened, and pure water is again supplied to the pure water tank.

The pressurizing force of the pressurized fluid acts on the pure water in the pure water tank, and when the stop valve of the internal pressure adjusting means is opened, the pressurizing force escapes there. Therefore, the stop valve of the internal pressure adjusting means remains closed.

However, when the stop valve is closed, the pressure inside the pure water tank becomes higher than the pressure applied fluid due to the rise in the water level of the pure water tank. To release the increase, the stop valve of the internal pressure adjusting means is opened.

(7) When the pure water reaches the liquid level sensor again, the stop valve of the pure water supply pipe is closed.

(8) The supply pressure of the pure water in the factory, the magnitude of the fluctuation, and the positional relationship between the pure water tank and the liquid level sensor will be described. The pressure rise inside the pure water tank varies depending on the rising speed of the water level of the pure water tank.

In general, the shorter the distance between the upper liquid level sensor and the lower liquid level sensor and the larger the space above the upper liquid level sensor, the smaller the pressure rise.

(9) In order to reduce the space above the liquid level sensor at the top and to reduce the size of the pure water tank, an appropriate number of other adjustment units are added in addition to the adjustment unit of the internal pressure adjustment means. Then, the pressure rise in the space above the pure water tank may be quickly adjusted.

Further, separately, a pressure sensor is provided in the pure water tank, and the pressure in the space above the liquid level sensor at the top is monitored, and the monitored value is used as a stop valve of the internal pressure adjusting means using a controller. It can be fed back to the control. This enables more precise water level adjustment of the pure water tank.

(10) The flow rate of the pure water flowing into the aspirator is basically determined by the pressure of the pressure applying fluid of the pressure applying means connected to the pure water tank. Variable (adjustable) between
No valve is required.

However, it is also possible to install a variable (adjustment) valve in this part depending on the conductance of the aspirator (easy flow of the liquid), the required dilution accuracy and the flow rate of the diluent.

The flow rate of a chemical solution flowing into the aspirator, for example, the flow rate of hydrofluoric acid basically depends on the characteristics of the aspirator. That is, the characteristic of the relationship between the flow rate of pure water to the inlet portion of the aspirator and the flow rate of the chemical solution sucked in the siphon portion of the aspirator is not linear in reality.

Therefore, the flow rate is adjusted (adjusted) to adjust the flow rate.
It is necessary to install a valve. In this case, a commercially available aspirator can be easily used, and an inexpensive liquid diluting device can be obtained.

However, since the variable (adjustment) valve must use a fluorine resin or the like in the liquid contact portion from the viewpoints of preventing contamination of pure water and maintaining chemical resistance to a chemical solution, the fluorine resin originally has Due to the creep characteristic, the hysteresis and backlash of the variable (adjustment) valve increase, and it is inevitable that the reproducibility is inferior.

However, an aspirator suitable for the required flow rate of the diluent, dilution concentration, and concentration of hydrofluoric acid used is
This variable (adjustment) valve is, of course, unnecessary if it can be easily manufactured. Hereinafter, a detailed description will be given based on embodiments.

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of _{a main} part of an embodiment of the present invention. An example in which a chemical solution having a predetermined concentration is diluted with pure water to a predetermined concentration will be described. FIG. 2 is an operation timing chart of FIG.

In the figure, the first pure water supply pipe 11
Is connected at one end to a factory pure water supply pipe A,
Is the pipe to be supplied. First pure water supply pipe 11
Has a filter FL172 and a regulator RG16
2. A needle valve NV142 is provided.

The first chemical supply pipe 12 is connected at one end to a chemical supply pipe C at a factory and is supplied with a chemical D having a predetermined concentration. The first chemical liquid supply pipe 12 includes a filter FL271, a regulator RG261,
A needle valve NV141 is provided.

The pure water tank DT101 is a tank to which the other end of the first pure water supply pipe 11 is connected. The pressure applying means 13 applies a pressure to the pure water B.

The pressure applying means 13 includes a pressure applying pipe 13
1, filter FL171, regulator RG161,
Stop valve SV121, needle valve NV141
And the pressure application fluid 1 applied to the pressure application pipe 131
32.

The pressure application pipe 131 is connected to a pure water tank DT.
One end is connected to 101. Pressure application pipe 131
A pressure application fluid 132 is applied to the other end. In this case, nitrogen, which is an inert gas, is used.

In the middle of the pressure application pipe 131, a filter FL171, a regulator RG161, a stop valve SV121 and a needle valve NV141 are provided.

The internal pressure adjusting means 14 includes a pure water tank DT10.
1 is an adjusting means for adjusting the internal pressure. In this case, as the internal pressure adjusting means 14, two adjusting units 141, 1
42.

The adjusting units 141 and 142 are respectively provided with adjusting pipes 1411, 1421, stop valves SV125, 126, and needle valves NV143, 1
44.

One end of each of the internal pressure adjusting pipes 1411 and 1421 is connected to the pure water tank DT101, and the other end is opened to the atmosphere. The stop valves SV 125 and 126 and the needle valves NV 143 and 144 are connected to the internal pressure adjusting pipe 1.
It is provided in the middle of 411,1421.

The pure water tank water level detecting means 15 is a detecting means for detecting a predetermined water level of the pure water tank DT101.
In this case, as the pure water tank water level detecting means 15, two liquid level sensors SR18 arranged at a predetermined interval E are provided.
1,182.

One end of the second pure water supply pipe 16 is connected to a pure water tank DT101.
A pipe through which pure water B from 1 passes. Chemical tank FT2
Reference numeral 01 denotes a tank to which the other end of the first chemical liquid supply pipe 12 is connected.

The atmosphere release pipe 17 is connected to the chemical tank FT2.
01 is a pipe connected at one end and open at the other end to the atmosphere. The chemical liquid tank water level detecting means 18 is provided with a chemical liquid tank F
It is a detecting means for detecting a predetermined water level of T201.

In this case, the chemical tank water level detecting means 18
Have two liquid level sensors SR281 and 282 arranged at a predetermined interval F.

One end of the second chemical liquid supply pipe 19 is connected to the chemical liquid tank FT201.
This is a pipe through which the chemical solution D from 1 passes. Aspirator AS
In 301, the other end of the second pure water supply pipe 16 is connected to the inlet, and the other end of the second chemical liquid supply pipe 19 is connected to the siphon section.

The stop valves SV122 and SV123 are valves provided in the middle of the first and second pure water supply pipes 11 and 16, respectively. Stop valve SV2
21 and 222 are first and second chemical supply pipes 12 and 1
9 are valves provided in the middle of 9.

The controller 21 controls the stop valves SV122, 123, 221, 22 based on the detection signals of the pure water tank water level detecting means 15 and the chemical liquid tank water level detecting means 18.
22, control the operation of the pressure applying means 13 and the internal pressure adjusting means 14.

The output pipe 22 is connected to the aspirator AS30.
One end of the pipe is connected to one outlet, and is a pipe from which a dilute solution having a predetermined concentration is output. The drain pipe 23 is a pipe having one end branched from the middle of the output pipe 22.

The stop valve SV322 is a valve provided on the output pipe 22 downstream of the branch point from the drain pipe 23. The stop valve SV321 is a valve provided in the middle of the drain pipe 23.

The operation of the above configuration will be described with reference to the timing chart of FIG.

(1) At t0, the stop valve SV122 is opened, and pure water B is injected into the pure water supply tank DT101 through the pure water supply pipe A of the factory.

The pressure of the pure water B is adjusted by the regulator RG162
Is adjusted to a constant value, but when the pressure fluctuation of the supply source, the pure water supply pipe A of the factory is large, the hydraulic pressure of the pure water A to be injected is influenced by the fluctuation.

However, while the stop valve SV122 is open, the pressure adjustment stop valve SV125 is opened to release the pressure inside the pure water tank DT101, thereby maintaining a constant value (atmospheric pressure).

Since the change of the supply water pressure of the pure water B from the factory changes to the change of the liquid level rising speed of the pure water tank DT101, it does not affect the flow rate of the pure water B to the aspirator AS301 described later. become.

(2) When pure water B reaches t3, liquid level sensor SR
182, and rises toward the liquid level sensor SR181. When the pure water B reaches the liquid level sensor SR181 at t5, the stop valve SV122 closes and the supply of pure water stops.

While the stop valve SV122 is closed, it is naturally not affected by the pressure fluctuation of the pure water supply pipe A of the factory. At the same time, stop valve SV12
5 is closed, the stop valve SV121 is opened, and nitrogen N2
Acts on the pure water B in the pure water tank DT101.

By opening the stop valve SV123,
Pure water B flows out to the aspirator AS301.

(3) On the other hand, in the chemical liquid tank FT201,
At t2, by opening the stop valve SV221,
Hydrofluoric acid is injected. At t4, the liquid level sensor SR282
Over the liquid level sensor SR281.

At time t6, when the hydrofluoric acid reaches the liquid level sensor SR281, the stop valve SV221 is closed. Stop valve SV222 opens and hydrofluoric acid is supplied to aspirator 3.
Flows to 01.

(4) The time t6 when the stop valve SV222 is opened is the time when the stop valve SV123 is opened.
Must be after t5. Thereby, pure water B
Flows, hydrofluoric acid D flows out by the suction force generated in the aspirator AS301.

By accurately controlling the flow rate of pure water B, the flow rate of hydrofluoric acid D can be automatically controlled.
This is the basic reason why highly accurate dilution can be performed.

(5) After t6, both the pure water B and the hydrofluoric acid D flow through the outlet of the aspirator AS301. However, the dilution accuracy at the initial stage is poor. By opening the stop valve SV321, the liquid is discharged to the drain.

At this time, the stop valve SV322 is closed. After sufficient time has passed since t6 (usually 30-6
0 seconds), at time t7, the stop valve SV322 is opened,
By closing V321, the diluent can be supplied to the supply line.

(6) When the liquid level of the pure water tank DT101 becomes lower than the liquid level sensor SR182 (t9), the stop valve SV122 is opened, and the pure water B is again supplied to the pure water tank DT1.
01 is supplied.

The pure water B in the pure water tank DT101 is subjected to a pressurizing force of nitrogen N2, and the stop valve SV1
When 25 is opened, the pressing force starts flowing from here.
Therefore, the stop valve SV125 remains closed.

However, when the stop valve SV125 is closed, the pressure inside the pure water tank DT101 becomes higher than the nitrogen N2 pressure due to the rise in the water level of the pure water tank DT101. To release the increase, the stop valve SV126 is opened (t9 to t11).

(7) The pure water B is again supplied to the liquid level sensor SR18.
When it reaches 1, stop valves SV122 and 126 are closed.

(8) Supply pressure of pure water A at the factory, magnitude of its fluctuation, pure water tank DT101 and liquid level sensor SR18
A description will be given of the positional relationship with the first and the second 182. Pure water tank D
Depending on the rising speed of the water surface of T101, the pure water tank DT1
The pressure rise inside 01 is different.

In general, the shorter the distance between the liquid level sensors SR181 and 182 and the larger the space above the liquid level sensor SR181, the smaller the pressure rise.

(9) In order to reduce the space above the liquid level sensor SR181 and reduce the size of the pure water tank DT101, as shown in FIG. Unit 142-3, ...
Then, an appropriate number of pressure adjustment units may be added so that the pressure increase in the space above the pure water tank DT101 can be quickly adjusted.

Further, a pressure sensor SR184 is provided in the pure water tank DT101 to monitor the pressure in the space above the liquid level sensor SR181, and this monitor value is used by the controller 21 to stop valves SV126 and SV1.
26-2, SV 126-3,... Can be fed back to the valve control. This enables more precise water level adjustment of the pure water tank DT101.

(10) The flow rate of the pure water B flowing into the aspirator AS301 is basically the same as that of the pure water tank DT101.
Is determined by the pressure of the nitrogen N2 which is a pressure-applied fluid, and therefore a variable (adjustment) valve is not required between the pure water tank DT101 and the aspirator AS301.

However, depending on the conductance (ease of liquid flow) of the aspirator AS301, the required dilution accuracy and the flow rate of the diluent, etc., a variable (adjustment) valve is provided at this portion, as shown in FIG. Valve NV1
It is also possible to install 45.

The flow rate of hydrofluoric acid D flowing into the aspirator AS301 is basically the same as that of the aspirator AS30.
1 is dependent on the characteristics of For example, the required diluent B
Is 1.00 (l / min), the concentration of the hydrofluoric acid D after dilution is 1%, and the concentration of the hydrofluoric acid stock solution is 50%, the pure water flow rate is 0.98 (l / min), the hydrofluoric acid is The flow rate is 0.02 (1 / min).

However, the flow rate of pure water B was 0.98 (l /
), The flow rate of hydrofluoric acid flowing into the aspirator AS301 becomes 0.02 (1 / min) or more (Galtech; product No. 226-3).

That is, the flow rate of pure water B into the inlet portion of the aspirator AS301 and the flow rate of the aspirator AS301
The relationship characteristic with the flow rate of the chemical solution D sucked in the siphon section is not linear.

Therefore, in order to adjust the flow rate, it is necessary to install a variable (adjustment) valve, in this case, a needle valve NV242 or a needle valve NV145, as shown in FIG.

In this manner, the aspirator AS30
First, a commercially available product can be easily used, and an inexpensive liquid diluting device can be obtained.

However, the needle valves NV242 and NV1
No. 45 requires the use of a fluororesin in the liquid contact portion from the viewpoint of preventing contamination of pure water, maintaining chemical resistance to chemicals, and the like.
It is inevitable that the hysteresis and the backlash of the needle valves NV242 and NV145 become large and the reproducibility is inferior.

However, the aspirator AS adapted to the required flow rate of diluent, dilution concentration, and concentration of hydrofluoric acid used
If the valve 301 can be easily manufactured (however, it is considered to be very expensive and not economical), it is a matter of course that this variable (adjustment) valve is unnecessary.

As a result, (1) dilution accuracy is high. Aspirator AS3 for mixing method
01 is used to precisely control the flow rate of pure water on the entrance side of the aspirator AS301, and keep it constant.

Therefore, the flow rate (hydrofluoric acid) on the siphon side of the aspirator AS301 also becomes constant. Since pure water flow rate: hydrofluoric acid flow rate = dilution ratio, a diluent having a uniform dilution ratio is obtained immediately after the aspirator.

Conventionally, the two liquids are often mixed using the tanks 1 and 2, the uniformity of the obtained liquid mixture is low, and the dilution accuracy is poor. For example, if you target 0.5%,
0.5 ± 0.15%. In contrast, in the present invention, 1
Accuracy of ± 0.05% was obtained.

That is, since the two liquids are mixed using the aspirator AS301 and the flow rate of the two liquids is precisely controlled, a stirring mechanism is not required, and a dilution ratio equal to the target value can be obtained immediately after mixing. Therefore, the uniformity is good. In short, a liquid diluting device with high dilution accuracy can be obtained.

(2) The pressure of pure water and hydrofluoric acid from the factory is hardly fluctuated. In the apparatus of the present invention, the pure water tank DT101
Are connected to the following three systems.

1. Pressure applying means 13: Stop valve S
Line leading to V121. 2. Pure water supply means: a line connected to the stop valve SV122. 3. Internal pressure adjusting means: Stop valve SV125, 12
6. Line leading to etc.

A stop valve is installed in each of these, and the pressure and the water level inside the pure water tank DT101 are adjusted while the opening and closing are adjusted by the controller 21 with each other. When the pure water supply pressure from the supply line of the factory changes in the increasing direction, the rise of the water level inside the pure water tank DT101 becomes faster.

The pure water supply pressure from the factory supply line is
If it changes in the decreasing direction, the pure water tank DT101
The rise of the water level inside is slow. Only the above operation is performed, and only the pressure inside the pure water tank DT101 affects the flow rate of the pure water B flowing out toward the aspirator AS301.

For hydrofluoric acid, when the supply pressure of hydrofluoric acid from the supply line of the factory changes in the increasing direction, the level of hydrofluoric acid in chemical solution tank FT201 rises faster.

When the supply pressure of hydrofluoric acid from the supply line of the factory changes in a decreasing direction, the chemical solution tank FT2
01, the hydrofluoric acid water level rises slowly. Only the above operation is performed, and only the suction force of the aspirator AS301 generated by the flow rate of the pure water B affects the flow rate of the hydrofluoric acid D flowing toward the aspirator AS301.

As described above, if only the pressure inside the pure water tank DT101 is accurately controlled, the pressure fluctuation of the supply pressure of the pure water B and the hydrofluoric acid D at the factory will affect the dilution characteristics of the liquid diluting apparatus. Will not be.

That is, since the pure water tank DT101 is provided with the functions of the pressure applying means 13, the pure water supply means and the internal pressure adjusting means 14, when the pure water supply pressure of the factory rises / falls, the pure water tank DT101 becomes pure. The pressure inside the water tank DT101 can be adjusted, and the amount of pure water B supplied to the aspirator AS301 can be kept constant.

The flow rate of the hydrofluoric acid D flowing out of the chemical liquid tank FT201 depends only on the suction force of the aspirator AS301, and therefore does not affect the supply pressure of the hydrofluoric acid D at the factory.

Since the flow rates of the pure water B and the hydrofluoric acid D are not affected by the supply pressure fluctuation of the factory, the dilution characteristics of the liquid diluting device are not affected by the pressure fluctuation of the factory. In short, a liquid diluting device that is not affected by fluctuations in the supply pressure of the factory can be obtained.

(3) High reproducibility. Even without using the variable (adjustment) valve NV145 in the line through which the pure water B flows, the flow rate of the pure water B can be controlled by the pressure applied fluid, in this case, the pressure of the nitrogen N2.

When hydrofluoric acid is used, the variable valve NV145 is made of a fluorine resin valve NV145.

The valve NV145 made of a fluorine resin has hysteresis and backlash based on the creep characteristic of the fluorine resin. Therefore, even if the valve NV145 is adjusted once (moved), it may move thereafter. Therefore, a liquid diluting apparatus with high reproducibility can be obtained from an apparatus configuration that does not employ a variable valve using a fluorine resin.

(4) The size of the device can be reduced. The pure water tank DT101 used in the apparatus of the present invention has, for example, a volume of about 2
~ 3 l, the chemical solution tank FT201 has a volume of about 0.5 l.

In the conventional method of mixing the two liquids in the tanks 1 and 2, a mixing tank having a volume of about 20 l or more is required for temporary storage for stirring after mixing. .

In the apparatus of the present invention, no mixing tank is required. Considering related parts, etc., it is about 1 /
The size can be reduced by about 10 or more. Therefore, a liquid diluting device that can be easily miniaturized can be obtained.

(5) Pure water B is supplied to the aspirator AS301.
Is applied to the pure water tank DT101 in order to extrude the water. By using a fluid as the application medium, pressure can be transmitted through a complicated path, and the degree of freedom in apparatus design (the degree of freedom in laying out piping) is increased, and a liquid diluting apparatus that can be easily miniaturized is obtained. Can be

(6) By using an inert gas as the pressure-applying fluid, a liquid diluting device capable of maintaining a constant purity (specific resistance value) of pure water B even when contacting with pure water B can be obtained. .

(7) By using nitrogen N2 as the inert gas, this operation can be performed without lowering the purity of the pure water B. Further, since nitrogen gas N2 is relatively easily available and inexpensive at a semiconductor manufacturing site where the present apparatus is installed, the running cost when operating the apparatus can be reduced, and the running cost can be reduced. However, an inexpensive liquid diluting device can be obtained.

(8) As a means for adjusting the internal pressure, a pure water tank D
An adjusting unit 141 having an internal pressure adjusting pipe 1411 having one end connected to T101 and the other end open to the atmosphere, and a stop valve SV125 and a needle valve NV143 provided in the middle thereof is used.

Thus, when the internal pressure of the pure water tank DT101 rises, by opening the stop valve SV125, the internal pressure can be instantaneously released to the outside through the pipe 1411 to reduce the pressure. A device is obtained. The speed at which the pressure is reduced is adjusted by the needle valve NV143.

As a means for adjusting the pressure, generally,
A gas pressure regulator is used. The pressure regulator (regulator) is configured to keep the secondary pressure (low pressure) constant even if the primary pressure (high pressure) fluctuates when the gas flows from the high pressure side to the low pressure side.

In this device, a pressure rise occurs instantaneously,
You need to lower it instantly. The pressure regulator cannot be used because the response time is long and the pressure cannot be reduced instantaneously.

(9) As a cause of an increase in the internal pressure of the pure water tank DT101, pure water B is supplied from the outside to the pure water tank DT101, the water level inside the pure water tank DT101 rises, and Pressure rise due to smaller internal space.

[0126] Nitrogen N2 is supplied from the outside to the pure water tank DT101, and the internal pressure of the pure water tank DT101 rises due to the pressure fluctuation of the nitrogen N2. Other.

If (internal pressure adjusting pipe + stop valve + needle valve) is prepared for each,
According to each cause, the pressure can be adjusted instantaneously, more precise pressure control can be performed, the flow rate of pure water B can be stabilized, and a liquid diluting device that can improve the dilution accuracy can be obtained.

(10) In the pure water tank DT101, two liquid level sensors SR182 and SR181 for a low water level (Low) and a high water level (High) are arranged at predetermined intervals. .

When the liquid level decreases, pure water B is supplied from the outside, and when the liquid level increases, pure water supply stops. The narrower this interval is,

The change in the water level of the pure water B is reduced, and the influence of gravity is reduced. The change in the upper space of the pure water tank DT101 is small, and the influence of the pressure fluctuation is small.

As a result, a liquid diluting apparatus which can stabilize the flow of the pure water B toward the aspirator AS301 and improve the dilution accuracy can be obtained.

However, the number of times of ON / OFF of the supply of the pure water B is increased, so that the opportunity of operating the pressure adjusting unit may be increased, and conversely, the pressure fluctuation may be increased. In general, if the supply pressure of pure water B in a factory is stable, even if the number of ON / OFF times of the supply of pure water B increases, the pressure fluctuation does not affect the dilution characteristics. Therefore, it is better that the interval between the low water level and the high water level is small.

Conversely, if the supply pressure of pure water B at the factory is unstable, the more the number of ON / OFF times of the supply of pure water B increases, the more the pressure fluctuation may affect the dilution characteristics. . Therefore, it is better to increase the interval between the low water level and the high water level.

As described above, by adjusting the interval between the low water level and the high water level, a liquid diluting apparatus capable of minimizing the influence of the pressure fluctuation of the pure water B supplied to the factory can be obtained.

(11) Similarly to the pure water tank DT101, the chemical liquid tank FT201 has two liquid level sensors SR281 and SR2 for a low water level (Low) and a high water level (High).
82 are arranged at predetermined intervals.

If the supply pressure of the chemical solution D at the factory is stable, the ON / OFF frequency of the chemical solution supply is increased, and the water level of the chemical solution tank FT201 is made constant and the flow to the aspirator AS301 is reduced. It can be stabilized (constant liquid level = constant influence of gravity = flow rate is determined only by suction force of aspirator AS301). Therefore, it is better that the interval between the low water level and the high water level is small.

If the supply pressure of the chemical solution D at the factory is unstable, the liquid surface level fluctuates as the number of times of chemical solution supply ON / OFF increases. In an extreme case, the liquid surface of the chemical solution D is disturbed as it undulates, disturbing the sensitivity (liquid level recognition) of the liquid level sensors SR281 and SR282, and the low water level (Low) and the high water level (Hig
When the interval of h) is small, low water level (Low) and high water level (High)
May not be identified.

On the other hand, unlike the pure water tank DT101, since the chemical liquid tank FT201 is open to the atmosphere, the change in the space above the chemical liquid tank FT201 does not directly change from pressure fluctuation to flow rate fluctuation. From the above perspective, the low water level (Lo
It is better to increase the interval between w) and the high water level (High).

As described above, in this apparatus, the low water level (Low)
By optimizing the interval between the pressure and the high water level (High), it is possible to minimize the influence of the pressure fluctuation in the factory.

(12) When the pressure sensor SR184 is installed in the pure water tank DT101, as described in (9),
It is possible to more precisely adjust the pressure even when the pressure rises due to the following factors.

By devising an algorithm for inputting the accuracy of the pressure sensor SR184 and the value monitored by the pressure sensor SR184 to the controller 21 and feeding it back to the valve control, pressure control with good responsiveness becomes possible, and the dilution accuracy is improved. Is obtained.

(13) There are the following two methods for changing the dilution ratio. The structure of the aspirator AS301 is changed to change the pressure-flow characteristics. The pressure applied to the pure water tank DT101 is changed.

In this case, the aspirator AS301 must be newly formed from a mold, which is actually difficult.
Is a method for actually operating the present apparatus.

However, in this case, the aspirator AS30
Within the range of the combination of the flow rate-pressure characteristic of 1 and the pressure applied to the pure water tank DT101, the required dilution ratio may not be realized.

In this case, a required dilution ratio can be obtained by installing a needle valve NV145 in the middle of the pure water supply pipe 16 and adjusting it.
A liquid diluting device capable of realizing a wider range of dilution ratio is obtained. However, since the needle valve NV145 has backlash and hysteresis, there is a risk that reproducibility may be reduced instead of frequent adjustment.

(14) As described in (13),
Needle valve NV242 in the middle of chemical solution supply pipe 19
The flow rate of the chemical solution D flowing to the aspirator AS301 can be changed by installing and adjusting this. As a result, a liquid diluting device capable of obtaining a wide range of dilution ratio is obtained.

(15) When a computer is used as the controller 21, various settings can be easily changed. This makes it easy to optimize the conditions, and provides a liquid diluting device that can easily satisfy the required dilution ratio.

(16) Immediately after the pure water B and the chemical solution D flow into the aspirator AS301, the mixing ratio is not stable, and the dilution ratio is different from the required value. In this case, the outlet (outlet) of the aspirator AS301 is branched, and one is connected to an output line (use point) and the other is connected to a drain (discard line).

During the period in which the mixing ratio is unstable (generally, 30 to 60 seconds after the pure water B or the chemical solution D starts flowing), the mixture is allowed to flow to the drain side, To the output line side. By this,
At the point of use, a liquid diluting device that can always obtain a diluent having a required dilution ratio can be obtained.

[0150]

As described in detail above, the present invention provides
According to the first aspect of the present invention, (1) Since the two liquids are mixed using an aspirator and the flow rate of the two liquids is accurately controlled, a stirring mechanism is not required, and the target value is set immediately after mixing. As a result, a good dilution ratio can be obtained. In short, a liquid diluting device with high dilution accuracy can be obtained.

(2) Since the pure water tank is provided with functions of a pressure applying means, a pure water supply means, and an internal pressure adjusting means, when the pure water supply pressure at the factory rises / falls, the pure water tank is operated. It is possible to adjust the internal pressure of the aspirator, and to keep the amount of pure water supplied to the aspirator constant.

The flow rate of hydrofluoric acid flowing out of the chemical tank is
Since the suction pressure of the aspirator alone is used, the fluctuation of the supply pressure of hydrofluoric acid at the factory has no effect. Since the flow rates of pure water and hydrofluoric acid are not affected by the supply pressure fluctuation of the factory, the dilution characteristics of the liquid diluting device are not affected by the pressure fluctuation of the factory. In short, a liquid diluting device that is not affected by fluctuations in the supply pressure of the factory can be obtained.

(3) The flow rate of the pure water was controlled by the pressure of the pressure-applied fluid without using a variable (adjustment) valve in the line through which the pure water flows. Therefore, a liquid diluting apparatus with high reproducibility can be obtained from an apparatus configuration that does not employ a variable valve using a fluorine resin.

(4) In the apparatus of the present invention,
Since the pure water supply means, the internal pressure adjusting means, the water level detecting means and the controller for controlling these are provided, the pure water tank and the chemical liquid tank can be made smaller.

Further, no mixing tank is required. Therefore,
The size of the device can be reduced in consideration of related components and the like. Therefore, a liquid diluting device that can be easily miniaturized can be obtained.

According to the second aspect of the present invention, pressure is applied to the pure water tank in order to push pure water toward the aspirator. By using a fluid as the application medium, pressure can be transmitted through a complicated path, and the degree of freedom in apparatus design (the degree of freedom in laying out piping) is increased, and a liquid diluting apparatus that can be easily miniaturized is obtained. Can be

According to the third aspect of the present invention, the purity (specific resistance value) of pure water can be kept constant even when it comes into contact with pure water by using an inert gas as the pressure application fluid. A possible liquid diluting device is obtained.

According to the invention of claim 4 of the present invention, by using nitrogen as the inert gas, it is possible to perform the present operation without lowering the purity of pure water. Further, since nitrogen gas is relatively easily available and inexpensive at a semiconductor manufacturing site where this apparatus is installed, the running cost when operating the apparatus can be reduced, and the running cost can be reduced. An inexpensive liquid dilution device is obtained.

According to the fifth aspect of the present invention, as the internal pressure adjusting means, an internal pressure adjusting pipe having one end connected to the pure water tank and the other end open to the atmosphere, and a stop valve provided in the middle thereof And an adjustment unit having a needle valve.

In this way, when the internal pressure of the pure water tank rises, by opening the stop valve, the internal pressure can be instantaneously released to the outside through this pipe to reduce the pressure. Can be The speed at which the pressure is reduced is adjusted by a needle valve.

As means for adjusting the pressure, generally,
A gas pressure regulator is used. The pressure regulator (regulator) is configured to keep the secondary pressure (low pressure) constant even if the primary pressure (high pressure) fluctuates when the gas flows from the high pressure side to the low pressure side.

In this device, a pressure rise occurs instantaneously,
You need to lower it instantly. The pressure regulator cannot be used because the response time is long and the pressure cannot be reduced instantaneously.

According to the invention of claim 6 of the present invention, pure water is supplied to the pure water tank from the outside, and the water level inside the pure water tank rises as a cause of the increase in the internal pressure of the pure water tank. Pressure increase due to the smaller internal space of the pure water tank.

[0164] Nitrogen is supplied to the pure water tank from the outside, and the internal pressure of the pure water tank rises due to the pressure fluctuation of the nitrogen. Other.

If (internal pressure adjusting pipe + stop valve + needle valve) is prepared for each,
According to each cause, the pressure can be adjusted instantaneously, more precise pressure control can be performed, the flow rate of pure water B can be stabilized, and a liquid diluting device that can improve the dilution accuracy can be obtained.

According to the seventh aspect of the present invention, the pure water tank is provided with a low liquid level (Low) liquid level sensor and a high water level (Hig).
h) The two liquid level sensors were arranged at a predetermined interval.

When the liquid level decreases, pure water is supplied from the outside, and when the liquid level increases, pure water supply stops. The narrower this interval is,

[0168] The change in the pure water level is reduced, and the influence of gravity is reduced. Changes in the upper space of the pure water tank are reduced, and the effect of pressure fluctuation is reduced.

As a result, a liquid diluting device is obtained in which the flow of pure water toward the aspirator is stabilized and the dilution accuracy can be improved.

However, the number of times of ON / OFF of the supply of the pure water is increased, the operation opportunity of the pressure adjusting unit may be increased, and conversely, the pressure fluctuation may be increased.
Generally, if the supply pressure of pure water in the factory is stable,
Even if the number of ON / OFF times of the supply of pure water increases, the pressure fluctuation does not affect the dilution characteristics. Therefore, it is better that the interval between the low water level and the high water level is small.

Conversely, if the supply pressure of pure water in the factory is unstable, the ON / OFF count of the supply of pure water increases,
It is conceivable that the pressure fluctuation affects the dilution characteristics accordingly. Therefore, it is better to increase the interval between the low water level and the high water level.

As described above, by adjusting the interval between the low water level and the high water level, a liquid diluting apparatus capable of minimizing the influence of the pressure fluctuation of the pure water B supplied to the factory can be obtained.

According to the eighth aspect of the present invention, as in the case of the pure water tank, two liquid level sensors of a low water level (Low) and a high water level (High) are provided at a predetermined interval. Place with

If the supply pressure of the chemical solution D at the factory is stable, the number of ON / OFF operations of the chemical solution supply is increased, and the water level of the chemical solution tank is frequently set to be constant, so that the flow to the aspirator is stabilized. It is possible (constant liquid level = constant influence of gravity = flow rate is determined only by suction force of aspirator). Therefore, it is better that the interval between the low water level and the high water level is small.

If the supply pressure of the chemical solution at the factory is unstable,
As the number of times of ON / OFF of the supply of the chemical liquid increases, the liquid level changes accordingly. In extreme cases, the liquid surface of the chemical liquid is disturbed as it undulates, which disturbs the sensitivity of the liquid level sensor (liquid level recognition). If the interval between the low water level (Low) and the high water level (High) is small,
(Low) and high water level (High) may not be distinguished.

On the other hand, unlike the pure water tank, the chemical tank is open to the atmosphere, so that the change in the space above the chemical tank does not directly change from pressure fluctuation to flow rate fluctuation. From the above viewpoint, it is better to increase the interval between the low water level (Low) and the high water level (High).

As described above, in this apparatus, the low water level (Low)
By optimizing the interval between the pressure and the high water level (High), it is possible to minimize the influence of the pressure fluctuation in the factory.

According to the ninth aspect of the present invention, when the pressure sensor is installed in the pure water tank, the pressure sensor described in the sixth aspect is provided.
It is possible to more precisely adjust the pressure even when the pressure rises due to the following reasons.

By devising an algorithm for inputting the accuracy of the pressure sensor and the value monitored by the pressure sensor to the controller and feeding it back to the valve control,
Pressure control with good responsiveness becomes possible, and a liquid diluting device with improved dilution accuracy can be obtained.

According to the tenth aspect of the present invention, there are the following two methods for changing the dilution ratio. Change the structure of the aspirator and change the pressure-flow characteristics. The pressure applied to the pure water tank is changed.

In practice, the aspirator must be newly created from a mold, which is actually difficult. Is a method for actually operating the present apparatus.

However, in this case, the required dilution ratio may not be realized within the range of the combination of the flow rate-pressure characteristics of the aspirator and the pressure applied to the pure water tank.

In this case, a required dilution ratio can be obtained by installing a needle valve in the middle of the pure water supply pipe and adjusting the needle valve, and a liquid dilution device capable of realizing a wider range of dilution ratio. Is obtained. However, since the needle valve has backlash and hysteresis, there is a risk that reproducibility may be reduced instead of frequent adjustment.

According to the eleventh aspect of the present invention, as described in the tenth aspect, a needle valve is provided in the middle of the chemical solution supply pipe and adjusted by adjusting the needle valve.
The flow rate of the chemical solution flowing to the aspirator can be changed. As a result, a liquid diluting device capable of obtaining a wide range of dilution ratio is obtained.

According to the twelfth aspect of the present invention, when a computer is used as the controller, various settings can be easily changed. This makes it easy to optimize the conditions, and provides a liquid diluting device that can easily satisfy the required dilution ratio.

According to the thirteenth aspect of the present invention, immediately after pure water or a chemical solution flows into the aspirator, the mixing ratio is not stable, and the dilution ratio deviates from a required value. In this case, branch off the outlet of the aspirator,
One is connected to the output line (use point), and the other is connected to the drain (waste line).

The period during which the mixing ratio is unstable (generally, 30 to 60 seconds after the pure water or the chemical starts flowing)
Is allowed to flow to the drain side and, after stabilization, to the output line side. As a result, at the use point, a liquid diluting device that can always obtain a diluent having a required dilution ratio can be obtained.

Therefore, according to the present invention, a highly uniform diluent can be obtained, and a compact, easy-to-use, low-cost liquid diluting apparatus can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of FIG. 1;

FIG. 3 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of a configuration of a conventional example generally used in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 1st pure water supply pipe 12 1st chemical | medical solution supply pipe 13 Pressure application means 131 Pressure application pipe 131 Pressure application pipe 132 Pressure application fluid 14 Internal pressure adjustment means 141 Adjustment unit 142 Adjustment unit 142-2 Adjustment unit 142-3 Adjustment Unit 1411 Adjustment pipe 1421 Adjustment pipe 1421-2 Adjustment pipe 1421-3 Adjustment pipe 15 Pure water tank water level detecting means 16 Second pure water supply pipe 17 Atmospheric release pipe 18 Chemical liquid tank water level detecting means 19 Second chemical liquid supply pipe 21 Controller 22 Output pipe 23 Drain pipe A Factory pure water supply pipe B Pure water C Factory chemical supply pipe D Chemical liquid E Predetermined interval F Predetermined interval AS301 Aspirator DT101 Pure water tank FL171 filter FL172 filter L271 Filter FT201 Chemical tank NV141 Needle valve NV142 Needle valve NV143 Needle valve NV144 Needle valve NV144-2 Needle valve NV144-3 Needle valve NV145 Needle valve NV241 Needle valve NV242 Needle valve RG161 Regulator sensor RG1162 Regulator sensor RG1162 SR184 Pressure sensor SR281 Liquid level sensor SR282 Liquid level sensor SV121 Stop valve SV122 Stop valve SV123 Stop valve SV125 Stop valve SV126 Stop valve SV126-2 Stop valve SV126-3 Stop valve SV221 Stop valve V222 stop valve SV321 stop valve SV322 stop valve

Claims (14)

[Claims] 1. A first pure water supply pipe having one end connected to a factory pure water supply pipe and supplied with pure water, and a first chemical solution having one end connected to a factory chemical supply pipe and supplied with a chemical solution. A liquid diluting device including a supply pipe, a pure water tank to which the other end of the first pure water supply pipe is connected, and pure water from the pure water tank being supplied to an inlet portion, wherein the first chemical liquid is supplied. A liquid diluting device comprising: an aspirator connected to a siphon section for a chemical solution from a supply pipe and outputting a predetermined diluting liquid from an outlet. 2. A pressure applying means connected to the pure water tank for applying pressure to the pure water, an internal pressure adjusting means for adjusting an internal pressure of the pure water tank, and a pure water detecting means for detecting a predetermined water level in the pure water tank. Water tank water level detection means, a second pure water supply pipe having one end connected to the pure water tank and through which pure water from the pure water tank passes, and a chemical liquid connected to the other end of the first chemical liquid supply pipe A tank, an atmosphere release pipe having one end connected to the chemical tank and the other end open to the atmosphere, a chemical tank level maintaining means for maintaining a predetermined water level in the chemical tank, and one end connected to the chemical tank. A second chemical supply pipe through which the chemical from the tank passes; and an aspirator having the other end of the second pure water supply pipe connected to the inlet and the other end of the second chemical supply pipe connected to the siphon section. Wherein the middle of the first and the second pure water supply pipe first
And a stop valve respectively provided in the middle of the second chemical liquid supply pipe; the stop valve, the pressure applying means, and the internal pressure adjustment based on detection signals from the pure water tank water level detecting means and the chemical liquid tank water level detecting means. 2. The apparatus according to claim 1, further comprising: a controller for controlling an operation of the means.
The liquid dilution device according to claim 1. 3. A pressure application pipe having one end connected to the pure water tank, a pressure application fluid applied to the other end of the pressure application pipe, and a pressure application pipe provided in the middle of the pressure application pipe as the pressure application means. The liquid diluting device according to claim 2, further comprising a stop valve provided. 4. The liquid diluting apparatus according to claim 3, wherein an inert gas is used as the pressure applying fluid. 5. The liquid diluting apparatus according to claim 4, wherein nitrogen is used as said inert gas. 6. The internal pressure adjusting means includes an internal pressure adjusting pipe having one end connected to the pure water tank and the other end open to the atmosphere, and a stop valve and a needle valve provided in the middle of the internal pressure adjusting pipe. The liquid diluting device according to any one of claims 1 to 5, further comprising an adjusting unit. 7. The liquid diluting apparatus according to claim 6, wherein a plurality of said adjusting units are provided as said internal pressure adjusting means. 8. A liquid diluting apparatus according to claim 2, wherein said pure water tank water level detecting means includes two liquid level sensors arranged at a predetermined interval. . 9. The liquid diluting apparatus according to claim 2, further comprising two liquid level sensors arranged at a predetermined interval as a chemical liquid tank water level detecting means. 10. A pressure sensor is used as a pure water tank water level detecting means.
Alternatively, the liquid diluting device according to claim 9. 11. The liquid diluting device according to claim 2, further comprising a needle valve provided in the middle of the second pure water supply pipe. 12. The liquid diluting apparatus according to claim 2, further comprising a needle valve provided in the second chemical liquid supply pipe. 13. The liquid diluting apparatus according to claim 2, wherein a computer is used as said controller. 14. An output pipe having one end connected to an outlet of the aspirator and outputting a dilute solution having a predetermined concentration, a drain pipe having one end branched from the middle of the output pipe, and a branch point of the drain pipe. 14. A stop valve provided in the downstream output pipe, and a stop valve provided in the middle of the drain pipe.
The liquid diluting device according to any one of the above.