JP2000296899A - Method and apparatus for storing gas-dissolved water - Google Patents

Abstract

[57] [Abstract] [Problem] To maintain the concentration of dissolved gas required for gas-dissolved water without dissolving excess gas, prevent the dissolved gas from diffusing into the atmosphere in the gas phase, and pose a danger of recovery and explosion. Provided are a method for storing gas-dissolved water and a storage device for the same, which can eliminate the property. SOLUTION: A gas-dissolved water producing apparatus 3 for dissolving a gas in pure water, a storage tank 11 for storing the gas-dissolved water produced by the gas-dissolved water producing apparatus 3, an upper part of the storage tank 11, and a gas dissolved water. A pipe 12 for connecting a gas supply source of the manufacturing apparatus 3 and a control valve 1 for adjusting a gas flow rate flowing through the pipe 12
3 and a detection control device 14 for operating the control valve 13
And a gas dissolving water storage device comprising: a gas dissolving unit that stores a gas dissolving water in a storage tank 11; How to seal with

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to temporarily storing gas-dissolved water used for cleaning silicon wafers, liquid crystal glass substrates, etc., and for efficiently coping with a cleaning pattern. And a storage device for the storage device.

[0002]

2. Description of the Related Art In many cases, electronic components and members for manufacturing the same are cleaned with gas-dissolved water in which various gases are dissolved in pure water. The cleaning using the gas-dissolved water has a batch water supply pattern for intermittently supplying a large amount of the gas-dissolved water at one time other than a fixed water supply pattern for constantly supplying a fixed amount of the gas-dissolved water to the cleaning machine. . Installing a gas-dissolved water production device with a capacity corresponding to such a batch water supply pattern would make the device too large, so it would continue to produce gas-dissolved water even when gas-dissolved water was not used, and to store it in the storage tank. A method is used in which the gas is stored, and the amount of gas-dissolved water used for one batch cleaning is supplied during cleaning.

[0003] A method for storing the gas-dissolved water will be described with reference to FIG. Pure water produced by the pure water production device 50 is:
In the gas dissolving tank 51, a gas supply source, for example, a hydrogen supply source 52
Is dissolved and hydrogen-dissolved water is obtained. This hydrogen-dissolved water is sent to a storage tank 54 via a pipe 53,
Stored temporarily. Since the storage tank 54 is not particularly sealed, when the hydrogen-dissolved water starts to be stored in the storage tank 54, a liquid-phase part 55 of the hydrogen-dissolved water and a gas-phase part 56 of the atmosphere are generated. For this reason, the dissolved hydrogen in the hydrogen-dissolved water in the liquid-phase part 55 diffuses to the atmosphere side of the gas-phase part 56, causing a decrease in the dissolved hydrogen concentration in the hydrogen-dissolved water, and is directly sent to the use point B by the supply pump 57, When used for cleaning electronic components and members for manufacturing the same, there is a problem that cleaning failure occurs. In order to solve this, extra hydrogen is dissolved in pure water in anticipation of the amount of dissolved hydrogen that diffuses to the atmosphere side of the gas phase portion 56 while being stored in the storage tank 54.

[0004]

However, in the above conventional example, extra hydrogen is dissolved in pure water in anticipation of the amount of dissolved hydrogen diffusing to the atmosphere side of the gas phase portion 56, so that hydrogen is wasted correspondingly. Therefore, the hydrogen supply source 52 also needs to be large. In addition, depending on the type of gas, it is necessary to collect gas diffused to the atmosphere. When the gas is a hydrogen gas, the concentration of the hydrogen gas diffused into the gas phase portion 56 is 4%.
As described above, when the oxygen gas concentration of the gas phase portion 56 becomes 5% or more,
Risk of explosion.

Accordingly, an object of the present invention is to maintain a dissolved gas concentration required when using gas-dissolved water without dissolving excess gas, and to prevent the dissolved gas from diffusing to the atmosphere in the gas phase. Another object of the present invention is to provide a method for storing gas-dissolved water and an apparatus for storing the same, which can eliminate the danger of recovery operation and explosion.

[0006]

Under such circumstances, the present inventors have made intensive studies and as a result, have stored a gas, for example, hydrogen-dissolved water obtained by dissolving hydrogen in pure water as functional water in a storage tank. When the gas phase generated in the storage tank is sealed with hydrogen gas used in the production of the hydrogen-dissolved water, the dissolved hydrogen concentration in the production of the functional water can be maintained, and the dissolved hydrogen in the hydrogen-dissolved water is removed from the atmosphere. The present inventors have found out that it can be prevented from being diffused in, and have completed the present invention.

That is, according to the first aspect of the present invention, when a gas is dissolved in pure water and the obtained gas-dissolved water is stored in a storage tank, a gas phase generated in the storage tank is dissolved in the pure water. A method for storing gas-dissolved water characterized by sealing with the same gas as the gas. Thereby, the gas phase generated in the storage tank is sealed with the same gas as the gas-dissolved water, so that the dissolved gas does not diffuse to the atmosphere side of the gas phase and the concentration of the dissolved gas does not decrease. .

According to a second aspect of the present invention, a gas is dissolved in pure water,
When storing the obtained gas dissolved water in a storage tank,
The gas phase part generated in the storage tank is sealed with the same gas as the gas dissolved in the pure water, and when the storage tank is full with the gas-dissolved water, the sealing by the gas is stopped, It is an object of the present invention to provide a method for storing gas-dissolved water, characterized in that supply of gas-dissolved water is continuously caused to overflow from the storage tank. Thereby, when the storage tank is filled with the gas-dissolved water, the gas phase part is substantially eliminated and the sealing with the gas is stopped, so that only the gas necessary for the sealing is supplied to the storage tank. Gas is not wasted. On the other hand, since the gas-dissolved water continuously supplied to the storage tank overflows, a gas-phase portion directly interposed by the atmosphere does not occur unless the gas-dissolved water is used.

According to a third aspect of the present invention, the dissolved gas concentration in the gas-dissolved water is measured, and the gas partial pressure is calculated from the dissolved gas concentration so that the gas partial pressure is equal to or higher than the gas partial pressure. The present invention provides a method for storing gas-dissolved water, wherein the gas is supplied into the storage tank. As a result, it is possible to seal the gas in the storage tank from the optimal one according to the dissolved gas concentration in the gas dissolved water to the safe side. Here, the method of calculating the gas partial pressure from the dissolved gas concentration is performed according to a known method based on a calculation formula according to the type of gas. Ideally, the amount of gas supplied into the storage tank should be supplied so as to be the same as the gas partial pressure in the gas-dissolved water. Supplying at a higher pressure is preferable in that it can absorb a slight change in gas partial pressure and can reliably suppress the diffusion of dissolved gas into the atmosphere.

According to a fourth aspect of the present invention, there is provided a method for storing gas-dissolved water, wherein the storage tank is a one-bath cleaning tank provided in a cleaning apparatus for cleaning silicon wafers, liquid crystal glass substrates, and the like. It is. As a result, the concentration of dissolved gas in the gas-dissolved water in the one-bath washing tank does not drop below the set concentration, so that a constant level of washing water can always be supplied when washing silicon wafers, liquid crystal glass substrates, etc., and stable washing can be ensured. .

A fifth aspect of the present invention provides a gas-dissolved water producing apparatus for dissolving a gas in pure water, a storage tank for storing the gas-dissolved water produced by the gas-dissolved water producing apparatus, and an upper part of the storage tank. And a pipe connecting the gas supply source of the gas-dissolved water producing apparatus, a control valve for adjusting the pressure of gas flowing through the pipe, and a detection control device for operating the control valve. And a storage device for storing gas-dissolved water. This reliably realizes the method of storing gas-dissolved water for efficiently coping with a cleaning pattern in which a large amount of gas-dissolved water is used intermittently or at once.

[0012]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the pure water in which the gas is dissolved is not particularly limited. For example, a pretreatment device in which raw water is passed through a coagulating sedimentation device, a sand filtration device, and an activated carbon filtration device in order. Pretreatment water in the above, the purified water in the stage of the primary pure water production equipment stage which passed through the reverse osmosis membrane device, the two-bed three-column ion exchange device, the mixed bed type ion exchange device, the precision filter in order Furthermore, this primary pure water is subjected to ultraviolet irradiation, mixed bed polisher, ultrafiltration membrane treatment,
Fine particles, colloidal substances, organic matter,
Secondary pure water at the stage of the secondary pure water producing apparatus for removing metal ions, anions and the like, that is, so-called ultrapure water.

The gas dissolved in the pure water is not particularly restricted but includes, for example, ozone, oxygen, hydrogen, carbon dioxide and the like. The method for dissolving the gas in pure water is not particularly limited, but a film dissolving method in which the gas is injected into pure water through a gas permeable membrane to dissolve the gas, an aeration dissolving method in which the gas is dissolved in pure water by aeration, and a pure dissolving method. An ejector method in which gas is dissolved in water through an ejector, a pump stirring method in which gas is supplied to the suction side of a pump that sends pure water to a gas dissolving tank, and the gas is dissolved by turbulent flow in the pump, and the like.

Next, a method for storing gas-dissolved water according to the first embodiment of the present invention will be described with reference to the flowchart of the apparatus for storing gas-dissolved water shown in FIG. In the figure, a gas-dissolved water producing apparatus A is a pure water producing apparatus 1 for converting pre-treated water into pure water.
And a gas generator 2 for generating ozone, hydrogen and the like, and a gas dissolving tank 3 for dissolving a gas such as ozone and hydrogen in the pure water produced by the pure water producing apparatus 1. The pre-treated water is first sent to the pure water producing apparatus 1, and if it is a primary pure water producing apparatus, it is converted into primary pure water. Further, if it is treated by a secondary pure water producing apparatus, so-called ultra pure water is obtained. Can be The ultrapure water is sent to the gas dissolving tank 3 by the pipe 4, and the gas such as ozone and hydrogen supplied from the gas generator 2 through the pipe 5 is dissolved in the gas dissolving tank 3. Since the gas dissolving tank 3 employs the membrane dissolving method, the gas dissolving tank 3 is divided into a gas phase chamber 3a and a liquid phase chamber 3b by the gas permeable membrane 6 in the gas dissolving tank 3. Gas is injected from the gas phase chamber 3a of the gas dissolving tank 3, and passes through the gas permeable membrane 6 to be dissolved in the ultrapure water of the liquid phase chamber 3b.

The gas-dissolved water in which the gas is dissolved in the liquid phase chamber 3b is sent to the gas-dissolved water storage device 10 and stored according to the use conditions at the use point B. The gas-dissolved water storage device 10 includes a storage tank 11 for storing the gas-dissolved water produced by the gas-dissolved water production device A, and a storage tank branched from the pipe 5 connecting the gas generator 2 and the gas dissolution tank 3. The apparatus comprises a pipe 12 connected to an upper part of the pipe 11, a control valve 13 for adjusting a gas pressure flowing through the pipe 12, and a detection control device 14 for operating the control valve 13.

When storing gas-dissolved water in the storage tank 11, first, all of the gas in the storage tank 11 is in the gas phase portion 11a.
Since the atmosphere is full, the overflow valve 16 installed in the overflow line 15 is closed, the control valve 13 is opened, and gas is stored from the gas generator 2 through the pipe 5 and the pipe 12 branched from the pipe 5. While supplying the gas into the tank 11 and replacing the atmosphere in the storage tank 11 with a gas, the atmosphere is discharged from the pressure control valve 17 which has been released from the condition and opened, and the gas phase portion 11a in the storage tank 11 is discharged. Seal with gas. At the same time as starting to seal the gas phase portion 11a with gas, or while or after sealing, gas-dissolved water from the liquid-phase chamber 3b of the gas dissolving tank 3 is started to be injected into the storage tank 11 through the pipe 18, The phase part 11b is formed. After replacing the atmosphere in the storage tank 11 with the gas, the condition of the pressure control valve 17 is set to “close”, and the storage tank 1 is closed.
Charge the gas-dissolved water in 1 until it is full. When the liquid level sensor 19 installed in the storage tank 11 detects that the gas dissolved water is full, the liquid level sensor 19 sends the control valve 1
3 and a control signal 13 is closed. At the same time, an open signal is issued to the overflow valve 16 and the overflow valve 16 is opened,
The gas dissolved water is returned to the original liquid phase chamber 3b of the gas dissolving tank 3 through the overflow line 15. The supply pump 20 is operated based on the use command from the use point B, and the gas dissolved water stored in the storage tank 11 is operated.
, And is sent to use point B, and the gas-dissolved water is used according to the purpose of use at use point B.

When the gas-dissolved water is sent to the use point B by the supply pump 20, the gas-dissolved water in the storage tank 11 decreases.
An open signal is sent to the control valve 13 to open the control valve 13 and gas is sent. At the same time, a close signal is also sent to the overflow valve 16 by the liquid level sensor 19 to close the overflow valve 16 and the storage tank 11
The gas phase 11a generated therein is sealed with gas. When the use of the gas-dissolved water at the use point B is finished, the inside of the storage tank 11 is again filled with the gas-dissolved water.
, The control valve 13 is closed, and at the same time, an open signal is sent to the overflow valve 16 to open the overflow valve 16, and the gas-dissolved water flows through the overflow line 15 into the original gas-dissolved tank 3. Return to shared room 3b. Thereafter, the above is repeated. The detection control device 14 specifically shows the liquid level sensor 19 in the flow of the gas-dissolved water storage device in FIG. 1 and detects the amount of gas-dissolved water in the storage tank 11,
Based on the information, an open signal and a close signal are output to the control valve 13 and the overflow valve 16 to control the valves 13 and 16.

FIG. 2 is a flow chart of a gas dissolved water storage device according to a second embodiment of the present invention. In the figure, the same components as those of the first embodiment are denoted by the same reference numerals, the description thereof will be omitted, and different points will be described. That is, the difference between the gas dissolved water storage device 10a and the gas dissolved water storage device 10 shown in the embodiment of FIG.
8, the dissolved gas concentration meter 30 is attached, the pressure gauge 31 is attached to the pipe 12 adjacent to the storage tank 11, and the output (information) detected by the dissolved gas concentration meter 30 and the pressure gauge 31 is received. Control valve 13
In that it has a detection control device 14a including an operation controller 32 for issuing a supply amount command for adjusting the opening degree of the sensor. That is, the gas concentration of the gas-dissolved water flowing through the pipe 18 is detected by the dissolved gas concentration meter 30, and this gas concentration signal is sent to the arithmetic and control unit 32, where it is converted into the gas partial pressure of the gas-dissolved water. The opening degree of the control valve 13 is calculated based on the pressure and output to the control valve 13 as a supply amount command to adjust the opening degree of the control valve 13. On the other hand, the gas pressure of ozone or the like in the storage tank 11 is detected by the pressure gauge 31, and this gas pressure signal is sent to the arithmetic and control unit 32, where it is compared with the gas partial pressure calculated as described above. Calculate the opening of the control valve 13 to obtain a gas partial pressure if different, issue it to the control valve 13 as a precise supply amount command, and adjust the opening of the control valve 13 to reduce the gas pressure in the storage tank 11. Adjust to match the gas partial pressure of the gas dissolved water.

[0019]

According to the first aspect of the present invention, since the gas phase generated in the storage tank is sealed with the same gas as the gas-dissolved water, the dissolved gas diffuses into the atmosphere of the gas phase. And no decrease in dissolved gas concentration. Therefore, it is possible to maintain the required dissolved gas concentration when using gas-dissolved water without dissolving the excess gas, and to prevent the dissolved gas from diffusing to the atmosphere side in the gas phase to reduce the danger of recovery operation and explosion. Can be eliminated.

According to the second aspect of the present invention, when the inside of the storage tank is filled with the gas-dissolved water, the gas phase is substantially eliminated and the sealing by the gas is stopped, so that only the gas necessary for the sealing is stored in the storage tank. Gas will not be wasted. On the other hand, since the gas-dissolved water continuously supplied to the storage tank overflows, a gas-phase portion directly interposed by the atmosphere does not occur unless the gas-dissolved water is used. Therefore, in addition to the above effects, there is no wasteful use of gas, and there is no need to recover waste gas or perform detoxification processing.

According to the third aspect of the present invention, it is possible to properly seal the gas in the storage tank according to the concentration of the dissolved gas in the gas-dissolved water. Therefore, in addition to the above effects, the gas is not wasted more and more, the concentration of the dissolved gas in the gas-dissolved water is stabilized, and the purpose of use of the gas-dissolved water can be achieved.

According to the fourth aspect of the present invention, since the concentration of the dissolved gas in the gas-dissolved water in the one-bath cleaning tank does not drop below the set concentration, the cleaning effect of the silicon wafer, the liquid crystal glass substrate, etc. is always maintained at a constant level. become. Therefore, the strict cleaning conditions as described above can be easily cleared.

According to the fifth aspect of the present invention, there is provided a method for storing gas-dissolved water for efficiently handling stored gas-dissolved water even in a state where the performance of stored gas-dissolved water is difficult to maintain, such as a batch cleaning pattern. As a result, the performance of the stored gas-dissolved water can be stabilized.

[Brief description of the drawings]

FIG. 1 is a flow chart of a storage device for gas-dissolved water showing a first embodiment of the present invention.

FIG. 2 is a flow chart of a gas dissolved water storage device according to a second embodiment of the present invention.

FIG. 3 is a flow chart of a gas dissolved water storage device showing a conventional example.

[Explanation of symbols]

 1,50 Pure water production apparatus 2 Gas generator 3,51 Gas dissolution tank 3a Gas phase chamber 3b Liquid phase chamber 4,5,12,15,18,21,53 Piping 6 Gas permeable membrane 10,10a Gas dissolved water Storage device 11, 54 Storage tank 11a, 55 Gas phase portion 11b, 56 Liquid phase portion 13 Control valve 14, 14a Detection control device 15 Overflow line 16 Overflow valve 17 Pressure control valve 19 Liquid level sensor 20, 57 Supply pump 30 Dissolution Gas concentration meter 31 Pressure gauge 32 Arithmetic controller 52 Hydrogen source A Gas dissolved water production equipment B Use point

Claims (5)

[Claims] When a gas is dissolved in pure water and the obtained gas-dissolved water is stored in a storage tank, a gas phase generated in the storage tank is filled with the same gas as the gas dissolved in the pure water. A method for storing gas-dissolved water, characterized by sealing. 2. When dissolving a gas in pure water and storing the obtained gas-dissolved water in a storage tank, a gas phase generated in the storage tank is the same as the gas dissolved in the pure water. When the storage tank is filled with the gas-dissolved water while sealing with gas, while stopping the sealing by the gas, the supply of the gas-dissolved water is allowed to continuously overflow from the storage tank. Characteristic method of storing gas-dissolved water. 3. A method for measuring the concentration of a dissolved gas in the gas-dissolved water, calculating a gas partial pressure from the dissolved gas concentration, and storing the gas partial pressure in the storage tank so as to be equal to or higher than the gas partial pressure. 2. The method according to claim 1, wherein the gas is supplied. 4. The storage tank according to claim 1, wherein the storage tank is a one-bath cleaning tank provided in a cleaning apparatus for cleaning a silicon wafer, a liquid crystal glass substrate, or the like.
The method for storing gas-dissolved water according to item 6. 5. A gas-dissolved water producing apparatus for dissolving a gas in pure water, a storage tank for storing the gas-dissolved water produced by the gas-dissolved water producing apparatus, an upper part of the storage tank and the gas-dissolved water. A gas comprising: a pipe for connecting a gas supply source of a manufacturing apparatus; a control valve for adjusting a gas pressure flowing through the pipe; and a detection control device for operating the control valve. Device for storing dissolved water.