JP2020179372A - Gas dissolution water manufacturing apparatus and method - Google Patents

Abstract

To provide a gas dissolution water manufacturing apparatus which can increase a pressure of gas dissolution water without being restricted by a water pressure resistance of a gas dissolution membrane.SOLUTION: A gas dissolution water manufacturing apparatus that includes a gas dissolution membrane module including a gas phase chamber and a liquid phase chamber partitioned by a gas dissolution membrane and allows gas to be dissolved in treated water and manufactures gas dissolution water includes: a boost pump which boosts the gas dissolution water installed on a secondary side of the liquid phase chamber.SELECTED DRAWING: Figure 1

Description

The present invention relates to a gas-dissolved water production apparatus and method using a gas-dissolved membrane module.

In the field of electronic device manufacturing, gas-dissolved water in which gas is dissolved in pure water is used as water used for cleaning in a process using a liquid called a wet process.

In Patent Document 1, a gas dissolution film module having a gas permeable film (hereinafter, may be simply referred to as a “film module”) is used to dissolve a functional gas in pure water (ultrapure water). A method for producing functional water is disclosed. In this method, for the purpose of maintaining a stable supply pressure of the functional water to be produced, the water pressure of the pure water supplied from the pure water production apparatus is lowered by a pressure reducing valve, and then the pressure amount can be adjusted. It is disclosed that pure water is pressurized by a pump and then a functional gas is dissolved in pure water to produce functional water. In this way, the booster pump that boosts pure water is provided on the primary side of the liquid phase chamber of the membrane module.

JP-A-2017-131852

When the distance from the gas-dissolved water production device to the cleaning device for semiconductor parts (hereinafter, simply referred to as "cleaning device") is long, or when the cleaning device is placed at a higher position than the gas-dissolved water production device. In particular, the gas-dissolved water may contain air bubbles in the main piping in the cleaning equipment. Such a phenomenon can cause poor cleaning and should be suppressed. In order to suppress such a phenomenon, it is effective to increase the water pressure of the gas-dissolved water.

On the other hand, the water pressure in the liquid phase chamber of the membrane module must be equal to or lower than the water pressure resistance (specification pressure) of the gas dissolution membrane. Since the booster pump exists on the primary side of the liquid phase chamber, the water pressure of the line downstream from the liquid phase chamber must be equal to or lower than the water pressure resistance of the gas dissolution membrane. In addition, in this specification, unless otherwise specified, the term "downstream" refers to the flow direction of the fluid flowing through the line or equipment referred to.

That is, it may not be possible to increase the water pressure of the gas-dissolved water due to the restriction due to the water pressure resistance.

An object of the present invention is to provide a gas-dissolved water production method and an apparatus capable of increasing the pressure of the gas-dissolved water without being limited by the water pressure resistance of the gas-dissolved film.

According to one aspect of the invention
A gas-dissolved water production apparatus for producing gas-dissolved water by dissolving gas in water to be treated, which includes a gas-dissolved membrane module including a gas-phase chamber and a liquid-phase chamber partitioned by a gas-dissolved membrane.
Provided is a gas-dissolved water producing apparatus, which is installed on the secondary side of the liquid phase chamber and includes a step-up pump for boosting the gas-dissolved water.

According to another aspect of the invention
A gas-dissolved water production method for producing gas-dissolved water by dissolving gas in water to be treated using a gas-dissolved membrane module having a gas-phase chamber and a liquid-phase chamber partitioned by a gas-dissolved membrane.
Provided is a method for producing gas-dissolved water, which comprises a step of boosting the pressure of gas-dissolved water by using a pressure-pressing pump installed on the secondary side of the liquid phase chamber of the gas-dissolved film module.

According to the present invention, it is possible to provide a gas-dissolved water production method and an apparatus capable of increasing the pressure of the gas-dissolved water without being limited by the water pressure resistance of the gas-dissolved film.

It is a process flow diagram which shows the schematic configuration example of the gas dissolution water production apparatus and the example of a water supply destination apparatus. It is a process flow diagram which shows another example of the schematic structure of the gas dissolution water production apparatus. It is a process flow diagram which shows the schematic structure example of the cleaning apparatus of a semiconductor part.

In the present invention, the gas-dissolved water is produced by dissolving the gas in the water to be treated using the gas-dissolved membrane module. The membrane module comprises a gas phase chamber and a liquid phase chamber partitioned by a gas dissolution membrane. The gas dissolution membrane is a membrane having gas permeability (substantially impermeable to liquid water), and is also called a gas-liquid separation membrane or a gas separation membrane. Then, the gas-dissolved water is boosted by using a booster pump provided on the secondary side of the liquid phase chamber. As a result, the pressure of the gas-dissolved water can be increased without being limited by the water pressure resistance of the gas-dissolved film, and as a result, the mixing of air bubbles in the water supply destination device, particularly the main pipe in the semiconductor component cleaning device, is suppressed. be able to.

The water to be treated is typically pure water, but may be carbonated water, for example. Carbon dioxide gas is previously dissolved in pure water and used as the water to be treated, and ozone can be dissolved in the water to be treated. In the following, pure water will be described as an example of the water to be treated. The resistivity of pure water (25 ° C.) is, for example, 0.1 MΩ · cm or more. With respect to the present invention, "pure water" also includes water of more than 15 MΩ · cm or more than 18 MΩ · cm called ultrapure water.

The gas-dissolved water can be used for cleaning, rinsing, promoting oxidation, suppressing oxidation, and the like of silicon wafers and glass substrates, for example, in a cleaning device for semiconductor parts. Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

[First form]
FIG. 1 shows an example in which a gas-dissolved water production device 1 (ozone-dissolved water production device) that dissolves ozone and a semiconductor component cleaning device 100 as a water supply destination device are connected by a line L100.

Pure water is supplied to the membrane module 2 arranged in the gas-dissolved water production apparatus via the line L1, and ozone-containing gas is supplied via the line L14. The membrane module 2 includes a gas dissolving membrane 3, and the gas phase chamber 4 and the liquid phase chamber 5 are partitioned by the gas dissolving membrane 3. For example, the membrane module 2 is filled with a large number of fluororesin hollow fiber membranes, and pure water is supplied to the inside of the hollow fiber membranes and ozone-containing gas is supplied to the outside. That is, in this case, the liquid phase chamber 5 is formed inside the hollow fiber membrane, and the gas phase chamber 4 is formed outside. As shown in FIG. 1, gas can be supplied from the lower side of the membrane module 2, pure water can be supplied from the upper side, and these can be flowed in a countercurrent manner, but this is not the case. For example, gas may be supplied from the upper side of the membrane module 2, pure water may be supplied from the lower side, and these may flow in a countercurrent direction.

For example, by using a gas obtained by adding a small amount of nitrogen gas (supplied via line L11) to oxygen gas (supplied via line L12) as a raw material and ozoneizing the oxygen with an ozone gas generator 14. , Ozone-containing gas can be obtained on line L14. In this case, for example, the ozone gas content of the ozone-containing gas is about 10 to 30 vol%, and most of the rest is oxygen. Ozone has the property of autolyzing, which is more pronounced in the ozone-dissolved water state than in the ozone-containing gas state. In order to suppress the autolysis of ozone, carbon dioxide gas (supplied from line L13) can be added to the ozone-containing gas before being supplied to the membrane module 2. Alternatively, carbon dioxide gas may be added on the primary side of the ozone gas generator 14. Alternatively, the autolysis of ozone can be suppressed by previously dissolving carbonic acid in pure water to obtain carbonated water and supplying this to the liquid phase chamber 5. Mass flow controllers 11 to 13 can be provided on the lines L11 to L13, respectively, in order to adjust the flow rates of nitrogen gas, oxygen gas and carbon dioxide gas.

A part of the ozone-containing gas supplied to the gas phase chamber 4 is discharged from the gas phase chamber 4 to the line L15. An air supply pressure adjusting valve V3 is arranged on the line L15 in order to adjust the air supply pressure to the gas phase chamber 4, that is, the pressure of the ozone-containing gas at the inlet of the gas phase chamber. A surplus ozone gas decomposition catalyst cylinder 15 for detoxifying the surplus ozone gas can be arranged on the secondary side of the air supply pressure adjusting valve V3 of the line L15. Excess gas is discharged from the line L15.

Ozone-dissolved water is obtained on line L2 from the liquid phase chamber 5. The ozone concentration of the ozone-dissolved water can be measured with the dissolved ozone concentration meter 6 provided on the line L2. Ozone-dissolved water having a predetermined ozone concentration can be obtained by controlling the output of the ozone gas generator 14 or by operating the air supply pressure adjusting valve V3 to increase or decrease the air supply pressure in the gas phase chamber.

According to the present invention, the booster pump 7 is provided on the secondary side of the liquid phase chamber 5. That is, the booster pump 7 is connected to the outlet line L2 of the liquid phase chamber 5. The gas-dissolved water produced by the gas-dissolved water production apparatus 1 can be obtained from the outlet line L3 of the booster pump 7. The booster pump 7 can be used to increase the water supply pressure of ozone-dissolved water (outlet pressure of line L3) obtained from the gas-dissolved water production apparatus 1, and further adjust the ozone-dissolved water water supply pressure to a predetermined pressure. Can be done. In order to adjust the ozone-dissolved water feed pressure to a predetermined pressure, the pressure sensor P3 can be installed on the secondary side of the booster pump 7, that is, on the outlet line L3 of the booster pump. Since the pressure sensor P3 can also be used for guaranteeing the outlet water pressure of the gas-dissolved water production apparatus 1, it is preferable to install it. It should be noted that on-off valves V1 and V2 for cutting off the gas-dissolved water production apparatus 1 from other equipment can be provided in the vicinity of the inlet of the line L1 and the vicinity of the outlet of the line L3. In other lines, an on-off valve or the like for edge cutting can be appropriately provided even if it is not shown.

From the viewpoint of ozone resistance, the wetted portion of the booster pump 7 is preferably made of a fluororesin of trifluoroethylene or higher, and specifically, PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene / perfluoro). Alkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), PCTFE (polychlorotrifluoroethylene), ETFE (ethylene / tetrafluoroethylene copolymer) can be used.

The position where the dissolved ozone concentration meter 6 is installed may be the primary side (line L2) of the booster pump 7 or the secondary side (line L3).

In the example shown in FIG. 1, the ozone-dissolved water that has passed through the dissolved ozone concentration meter 6 is supplied to the cleaning device 100. As the dissolved ozone concentration meter 6, it is preferable to use an ultraviolet absorption type dissolved ozone concentration meter. This is because the wetted part can be made of a clean material having ozone resistance and therefore does not contaminate the ozone-dissolved water. In the polarograph type dissolved ozone concentration meter, the sensor part has an internal liquid, and if the diaphragm arranged to hold the internal liquid is damaged, the internal liquid may be mixed in the liquid to be measured. .. Therefore, when a polarograph type densitometer is adopted, it is preferable to install the densitometer in a branch pipe drawn from the gas-dissolved water pipe (line L2) and drain the sample water that has passed through the densitometer.

In order to monitor the air supply pressure to the gas phase chamber 4, a first pressure sensor can be provided in the pipe (line L14 or L15) connected to the gas phase chamber 4. As shown in FIG. 1, when the first pressure sensor P1 is provided in the pipe (line L14) connected to the inlet of the gas phase chamber 4, the measured value is used as the supply pressure to the gas phase chamber 4. Can be done. Alternatively, when the first pressure sensor P1 is provided in the pipe (line L15) connected to the outlet of the gas phase chamber 4 as described later with reference to FIG. 2, in the gas phase chamber 4, if necessary. The supply air pressure can be known in consideration of the pressure loss. The pressure loss in the gas phase chamber 4 can be obtained from the correlation (which can be obtained in advance) between the gas flow rate flowing through the gas phase chamber and the pressure loss. For this purpose, the flow rate of the gas supplied to or discharged from the gas phase chamber can be measured as needed.

As described above, the installation position of the first pressure sensor P1 may be the inlet or the outlet of the gas phase chamber. However, if the first pressure sensor P1 can be degraded by ozone gas, the higher humidity ozone gas may be more corrosive than the dry ozone gas, so the lower humidity gas chamber primary side ( It is preferable to install the first pressure sensor P1 on the line L14). On the other hand, when hydrogen gas is used as the air supply gas, there is no concern about corrosion as described above. In such a case, there is no difference as described above regardless of whether the first pressure sensor is installed on the primary side or the secondary side of the gas phase chamber. However, it is preferable to install the first pressure sensor P1 on the inlet side (line L14) of the gas phase chamber 4, especially when the pressure loss due to the ventilation of the gas phase chamber 4 is high. This is because the pressure of a gas having a higher pressure can be directly measured. In addition, when the first pressure sensor P1 is installed on any side of the gas phase chamber 4, it is preferable that the distance from the gas phase chamber 4 to the place where the first pressure sensor P1 is installed is short.

In order to monitor the water pressure on the primary side or the secondary side of the liquid phase chamber 5, a second pressure sensor can be provided in the pipe (line L1 or L2) connected to the liquid phase chamber 5. The water pressure on the secondary side of the liquid phase chamber 5 can be known directly or indirectly by using the second pressure sensor.

In the example shown in FIG. 1, the pressure sensor P2 provided at the outlet line L2 of the liquid phase chamber 5 is used as the second pressure sensor to monitor the water pressure on the secondary side of the liquid phase chamber 5. In this case, the measured value of the pressure sensor P2 can be used as the water pressure on the secondary side of the liquid phase chamber 5. The pressure sensor P4 provided on the line L1 is used to monitor the pressure of pure water received in the gas-dissolved water production apparatus 1.

Alternatively, the pressure sensor P4 can be used as the second pressure sensor, and the pressure sensor P2 can be omitted. In this case, the water pressure on the primary side of the liquid phase chamber 5 is monitored by the pressure sensor P4, and the water pressure on the secondary side of the liquid phase chamber 5 is subtracted from the measured value of the pressure sensor P4 by subtracting the pressure loss in the liquid phase chamber 5. Is calculated. The gas-dissolved water production apparatus 1 can further include an arithmetic unit (not shown) for this purpose. The pressure loss in the liquid phase chamber 5 can be estimated based on the correlation between the water flow rate and the pressure loss in the liquid phase chamber 5 in advance. The water flow rate can be measured by, for example, the flow rate sensor F1 provided on the line L1.

The supply pressure to the gas phase chamber 4 is lower than the water pressure on the secondary side of the liquid phase chamber 5, that is, the following equation is established at the outlet of the liquid phase chamber 5 of the membrane module. It is preferable to perform an air supply pressure adjusting step for adjusting the air supply pressure to the gas phase chamber 4.
Membrane module Air supply pressure to gas phase chamber <Water pressure of gas-dissolved water ... (1)
As a result, even if the water pressure in the liquid phase chamber 5 drops due to the suction operation of the booster pump 7, gas is prevented from being ejected from the gas phase chamber 4 into the liquid phase chamber 5 and air bubbles are mixed in the gas-dissolved water. be able to. As a result, it becomes easy to increase the supply pressure to the gas phase chamber 4 to increase the dissolved gas concentration of the gas-dissolved water. If gas is ejected from the gas phase chamber to the liquid phase chamber, the supply air pressure may not reach a predetermined value. In addition, when an optical type dissolved gas concentration meter is used, correct measurement may not be performed if air bubbles are mixed in the dissolved gas water. In addition, air bubbles may adhere to the flow sensor and cause measurement failure.

This air supply pressure adjustment can be performed by using the air supply pressure adjusting valve V3 while monitoring the air supply pressure in the gas phase chamber 4 and the water pressure on the secondary side of the liquid phase chamber 5. Therefore, the supply air pressure adjusting means for performing the supply air pressure adjusting step is provided with the supply air pressure adjusting valve V3. Further, the supply air pressure adjusting means can include a control device (not shown) for controlling the opening degree of the supply air pressure adjusting valve V3. When the second pressure sensor for monitoring the water pressure is installed only on the primary side of the liquid phase chamber 5, the air supply pressure adjusting means further includes the arithmetic unit for calculating the secondary side water pressure of the liquid phase chamber. Can be done.

By increasing or decreasing the gas pressure supplied to the gas phase chamber 4 of the dissolution film module, the dissolved gas concentration of the gas dissolution water becomes high or low. Since the dissolved gas concentration is approximately stable if the supply air pressure is constant, a predetermined supply air pressure is usually maintained when adjusting the supply air pressure. However, at this time, the predetermined air supply pressure is set so that the relationship between the water pressure on the secondary side of the liquid phase chamber 5 and the air supply pressure satisfies the above formula (1). Further, when the set predetermined air supply pressure does not satisfy the above formula (1), the air supply pressure can be changed to another value and the value can be maintained.

However, the relationship of the equation (1) is satisfied without adjusting the air supply pressure to the gas phase chamber 4, such as when the pressure of the water supplied to the liquid phase chamber 5 is sufficiently higher than the pressure in the gas phase chamber 4. If this is the case, it is not necessary to perform the air supply pressure adjustment step.

When manufacturing the gas-dissolved water used in the cleaning device 100 for semiconductor parts, the pressure (water pressure of the gas-dissolved water) in the main pipe in the cleaning device 100 becomes higher than the air supply pressure to the gas phase chamber 4. That is, it is preferable to perform the discharge pressure adjusting step of adjusting the discharge pressure of the booster pump 7 so as to satisfy the above formula (1). As a result, it is easy to more reliably suppress the mixing of air bubbles into the gas-dissolved water in the main pipe. The pressure in the main pipe will be described in detail later.

This discharge pressure adjustment can be performed by changing the rotation speed of the booster pump 7 based on the pressure in the main pipe in the cleaning device 100 and the supply air pressure (or the difference between these pressures) in the gas phase chamber 4. it can. The discharge pressure adjusting means that performs the discharge pressure adjusting step can receive a signal corresponding to the pressure in the main pipe from the cleaning device 100. Further, the discharge pressure adjusting means can input a signal corresponding to the supply air pressure of the gas phase chamber 4. Further, the discharge pressure adjusting means can include a control device (not shown) for controlling the rotation speed of the booster pump 7. As the booster pump 7, it is preferable to use a rotary booster pump whose rotation speed can be controlled by an inverter.

However, when the discharge pressure of the booster pump 7 is sufficiently higher than the pressure loss to the main pipe in the cleaning device 100, the formula is performed in the main pipe in the cleaning device 100 without adjusting the discharge pressure of the booster pump. When the relationship (1) is satisfied, it is not necessary to perform the discharge pressure adjusting step, and the discharge pressure or the boost width of the booster pump 7 can be made substantially constant. Further, as will be described in detail separately, in order to prevent hunting, the boost width of the boost pump 7, for example, can be made substantially constant without performing the discharge pressure adjusting step.

[Semiconductor parts cleaning device as a water supply destination device]
In the example shown in FIG. 1, the gas-dissolved water production device 1 is connected to one end of a closed pipe (line L100) for transferring the gas-dissolved water, that is, the ozone-dissolved water to the water supply destination device, and the semiconductor is connected to the other end. The component cleaning device 100 is connected. FIG. 3 shows a configuration example of the cleaning device 100. The cleaning device 100 has 12 cleaning chambers 101. Gas-dissolved water is supplied as cleaning water from line L100 to the main pipe or mother pipe (line L101) for gas-dissolved water of the cleaning device 100. The main pipe is divided into two (lines L102a and b). From the main pipes (lines L102a and b), a pipe (line L104) for supplying cleaning water to each cleaning chamber 101 branches. The two main pipes join the line L103 at the end of the cleaning device downstream of the branch to the line L104. The line L103 is provided with a pressure monitoring and adjusting mechanism 105. Further, the line L103 is provided with an ozone decomposer 106 to decompose dissolved ozone.

Although not shown in detail, the pressure monitoring and adjusting mechanism 105 includes a pressure sensor and a back pressure valve. By narrowing or widening the flow path opening of the back pressure valve using the pressure monitoring and adjusting mechanism 105, the water pressure in the main pipes (lines L102a and b) can be increased or decreased to adjust to a predetermined value. .. As a result, the amount of washing water discharged to each washing room 101 is maintained at a predetermined value. The back pressure valve has a piping part on one side of the diaphragm through which the liquid to be pressure flows flows, and gas (generally air) is supplied to the other side at an arbitrary pressure or by spring force. A pressure regulating valve (also called a constant pressure valve or the like) configured to apply a load to the diaphragm can be used.

Each line L104 is provided with a flow rate sensor F101 and a valve V101 with a flow rate adjusting mechanism that can independently switch between discharging and stopping the washing water. Each end of line L104 forms a nozzle 102. In the line cleaning chamber 101, the substrate 103 to be cleaned is arranged on the turntable 104 and rotated while being cleaned and dried. The washing drainage is discharged from each washing chamber 101 to the line L105, and the washing drainage joins the line L103.

[Pressure in the main pipe in the cleaning device]
The pressure in the main pipe in the cleaning device can be measured by providing a pressure gauge in the main pipe. The pressure measurement point in the main pipe is the primary side of the back pressure source (pressure monitoring and adjusting mechanism 105) connected to the main pipe. Alternatively, the design value of the pressure can be used as the pressure in the main pipe. Alternatively, when the pressure in the main pipe can be considered to be substantially equal to the pressure in the pipe (for example, the end of the line L100 in FIG. 1) at the inlet (immediately before the inlet) of the cleaning device, the pressure in the main pipe is used. The pressure can be grasped from the pressure in the pipe at the inlet of the cleaning device.

[Second form]
An example of a gas-dissolved water production apparatus for dissolving hydrogen will be described with reference to FIG. The same reference numerals are given to those having the same functions as the devices and lines shown in FIG. The matters common to the first embodiment will be omitted as appropriate. Although not shown in FIG. 2, in this form as well, the hydrogen-dissolved water obtained from the gas-dissolved water production device 1 can be sent to the semiconductor component cleaning device which is the water supply destination device. The supply air pressure adjusting step and the discharge pressure adjusting step can be performed in the same manner as in the above-described embodiment, but in the following description, the method of adjusting the supply air pressure in the gas phase chamber 4 in the supply air pressure adjusting step is different. The method of is explained.

The supply source of hydrogen gas is not particularly limited, but for example, a hydrogen gas generator by electrolysis of water may be used, or a hydrogen gas cylinder may be used. FIG. 2 shows an example of supplying hydrogen gas produced by electrolysis of water to the membrane module. Pure water as raw water for electrolysis is supplied to the hydrogen gas generator 21 from the line L21 branched from the pure water pipe (line L1) for supplying pure water to the membrane module 2. Hydrogen gas is obtained from the line L22 connected to the cathode chamber of the electrolytic cell of the hydrogen gas generator 21, and the hydrogen gas is supplied to the gas phase chamber 4 of the membrane module 2. Hydrogen gas and liquid water flow out from the cathode chamber of the electrolytic cell of the hydrogen gas generator 21, and in order to separate them, a gas-liquid separator (not shown) is used between the electrolytic cell and the membrane module 2. ) Is provided. The excess of the oxygen gas generated by electrolysis and the raw water for electrolysis is discharged via the line L23 connected to the anode chamber of the electrolytic cell.

In the case of hydrogen gas dissolution, hydrogen having a concentration of almost 100% can be used regardless of the supply source, and the entire amount of the gas supplied to the membrane module 2 can be dissolved in water. Therefore, in this embodiment, it is not necessary to provide the air supply pressure adjusting valve. By controlling the operation and stop of the hydrogen gas generator 21 or by controlling the electrolytic current value while keeping the on-off valve V21 provided in the outlet line L15 of the gas phase chamber 4 closed, the gas phase chamber 4 can be reached. The supply air pressure can be adjusted. If the hydrogen gas generator 21 is operated with the on-off valve V21 closed, the generated hydrogen gas raises the supply air pressure in the gas phase chamber 4. If the hydrogen gas generator 21 is stopped when the supply air pressure reaches a predetermined upper limit value, the supply air pressure is subsequently lowered as the hydrogen gas is dissolved. When the supply air pressure reaches a predetermined lower limit value, the hydrogen gas generator 21 is operated. By repeating such an operation, the air supply pressure can be adjusted.

Alternatively, an air supply pressure adjusting valve is provided on the line L22 to keep the pressure in the cathode chamber of the electrolytic cell constant, that is, to keep the pressure of the hydrogen gas generated in the hydrogen gas generator 21 at a predetermined pressure, and to keep the pressure of the hydrogen gas generated in the hydrogen gas generator 21 at a predetermined pressure. The pressure of the gas phase chamber 4 located downstream may be set to a pressure different from the predetermined pressure to dissolve the hydrogen gas. Further, the amount of air supplied to the gas phase chamber 4 can be controlled by the mass flow controller.

When the first pressure sensor P1 for monitoring the air supply pressure to the gas phase chamber 4 is provided on the line L15 as shown in FIG. 2, the pressure loss in the gas phase chamber 4 is taken into consideration as described above. , The air supply pressure to the gas phase chamber 4 can be obtained. Alternatively, the pressure sensor P1 can be provided in a pipe (line L22) connected to the inlet of the gas phase chamber 4.

A polarograph type or thermal conductivity detection type densitometer is used to measure the dissolved hydrogen concentration. As described above, these densitometers may retain the internal liquid or may elute metal from the wetted material. Therefore, it is preferable to provide a dissolved hydrogen concentration meter 8 in a branch pipe (line L4) branched from the gas-dissolved water, that is, the hydrogen-dissolved water pipe (line L2), and drain the liquid after measurement. The line L4 is appropriately provided with a flow rate sensor F2 and on-off valves V5 and V6 for edge cutting.

Also in the form shown in FIG. 2, it is preferable to perform the air supply pressure adjusting step of adjusting the air supply pressure to the gas phase chamber 4 to a pressure lower than the water pressure on the secondary side of the liquid phase chamber 5. This pressure adjustment controls the shutdown or electrolytic current value of the hydrogen gas generator 21 while monitoring the supply air pressure of the gas phase chamber 4 and the water pressure on the secondary side of the liquid phase chamber 5 known as described above. Can be done by doing. The supply air pressure adjusting means can include a control device (not shown) for controlling the operation stoppage of the hydrogen gas generator 21 or the electrolytic current value. When the second pressure sensor for monitoring the water pressure is installed only on the primary side of the liquid phase chamber 5, the air supply pressure adjusting means further includes the arithmetic unit for calculating the secondary side water pressure of the liquid phase chamber. Can be done.

When a hydrogen cylinder is used instead of the hydrogen gas generator 21, a pressure adjusting valve can be appropriately provided in the hydrogen gas supply line to the gas phase chamber 4 to adjust the supply pressure to the gas phase chamber 4.

As shown in FIG. 2, in a form in which the entire amount of gas supplied to the gas phase chamber 4 is dissolved in water, when the supply pressure of the gas phase chamber 4 is maintained at a predetermined value, the flow rate of water supplied to the liquid phase chamber 5 fluctuates. Regardless of this, gas-dissolved water having a substantially stable dissolved gas concentration can be obtained. However, the gas dissolution efficiency in the membrane module 2 may gradually decrease over time. When the gas dissolution efficiency decreases and the dissolved gas concentration decreases, the set value of the supply air pressure can be increased so that a desired dissolved gas concentration can be obtained.

Further, as a method of dissolving the entire amount of gas supplied to the gas phase chamber 4 in water as shown in FIG. 2, the supply air flow rate increases or decreases according to the increase or decrease of the water supply flow rate to the liquid phase chamber 5. Control is also often done. When this control method is performed, a flow meter for measuring the water supply flow rate to the liquid phase chamber 5 and a device for controlling and measuring the supply air flow rate (often using a mass flow controller) are installed. be able to. In this method of supplying the gas phase chamber 4 with the gas at the flow rate required to obtain the desired dissolved gas concentration, the dissolved gas concentration does not decrease due to the decrease in the dissolution efficiency of the dissolution film module.

In the form as shown in FIG. 1, in which only a part of the gas to be supplied is dissolved in water, if the gas is an ozone-containing gas, for example, the supply pressure is adjusted to a predetermined value (pressure). The higher the value is, the higher the dissolved ozone concentration is likely to be), and the ozone supply amount from the ozone gas generator 14 can be increased or decreased with respect to the measurement result of the dissolved ozone concentration meter 6 to obtain ozone water having a desired concentration. For example, in the case of a silent discharge type ozone gas generator, when the supply air flow rate is constant, the ozone concentration in the ozone-containing gas increases or decreases as the discharge output increases or decreases, so the supply air pressure and the supply air flow rate are set to predetermined values. In many cases, the dissolved ozone concentration is controlled by increasing or decreasing the discharge output. Even when the ozone gas generation is a water electrolysis type, the generated ozone gas concentration can be controlled by increasing or decreasing the electrolytic current value with respect to the measured value of the dissolved ozone concentration meter 6.

[Type of gas to be dissolved]
The type of gas to be dissolved is not particularly limited, and hydrogen gas, oxygen gas, nitrogen gas, ozone gas (usually a mixed gas of ozone gas and oxygen gas), carbon dioxide gas and the like can be used. Depending on the physical properties of the gas to be dissolved, pure water becomes gas-dissolved water showing different redox potentials and pH. When an inert gas that does not contribute to the redox potential is dissolved, an antioxidant effect and an effect of enhancing the cavitation effect during ultrasonic cleaning can be obtained.

[Additives to gas-dissolved water]
Further, an alkali or an acid can be added to the water before or after the gas is dissolved for the purpose of adjusting the pH. For example, the water quality can be changed to alkaline reducing by adding alkali to hydrogen-dissolved water (ammonia water, TMAH (tetramethylammonium hydroxide, etc.), etc.). As a result, the effect of removing fine particles on the substrate surface in the semiconductor component cleaning apparatus can be improved and charging can be suppressed.

[Dissolved gas concentration of gas-dissolved water]
When a gas is dissolved in pure water using a gas dissolution film module, it is pure according to Henry's law that "when the temperature is constant, the amount of substance and mass of the gas dissolved in a certain amount of liquid are proportional to the pressure." The amount of substance of the gas that dissolves in water is proportional to the air supply pressure to the gas phase chamber of the gas dissolution film module.

The dissolved gas concentration in the gas-dissolved water is about 50 to 100% of the saturated solubility (hydrogen gas: 1.61 mg / L, nitrogen gas: 18.7 mg / L) at 20 ° C. and 1 atm for hydrogen gas and nitrogen gas. As for oxygen gas, it is often used at about 0.1 to 1% of the saturated solubility (44.3 mg / L) at 20 ° C. and 1 atm. On the other hand, the dissolved ozone gas concentration in the ozone gas-dissolved water is often increased to about 50 to 200% of the saturated solubility (13.9 mg / L) at 27 ° C. and 1 atm. Particularly in the case of ozone-dissolved water it is known to remove the effect of the resist residue by the high density becomes conspicuous, and is often utilized a high concentration ozone dissolved water of 100 mg O 3 / _L more than. The present invention is particularly suitable in such cases.

[Boost pump on the secondary side of the membrane module]
As the booster pump provided on the secondary side of the liquid phase chamber of the membrane module, a pump capable of boosting water can be appropriately used. The booster pump may be selected based on the lift and discharge rate, corrosion resistance to the gas-dissolved water to be boosted, and the like. For example, a non-volumetric centrifugal pump, a propeller pump, a positive displacement reciprocating pump, a rotary pump, or the like can be used. However, when cleanliness is particularly required, such as in the manufacturing process of semiconductor parts, a centrifugal pump (corresponding to a non-positive displacement centrifugal pump) or pulsation equipped with a magnetically levitated impeller that does not generate dust due to sliding of the rotating shaft. A diaphragm pump equipped with a removal mechanism (corresponding to a positive displacement reciprocating pump) is suitable.

[Air supply pressure]
The air supply pressure to the gas phase chamber 4 usually exceeds atmospheric pressure and is determined in relation to the water pressure on the secondary side of the liquid phase chamber 5. A specific example thereof is about 20 to 150 kPa.

[Receiving pure water pressure (pressure sensor P4)]
The receiving pure water pressure can be appropriately set from the viewpoint of ensuring the discharge amount of the gas-dissolved water from the gas-dissolved water production apparatus. A specific example thereof is about 100 to 500 kPa.

[Water pressure on the secondary side of the liquid phase chamber 5 (suction pressure of the booster pump 7) (pressure sensor P2)]
If the amount of water supplied from the gas-dissolved water production apparatus increases with the operation of the booster pump 7, the water pressure may decrease on the primary side of the booster pump 7. The water pressure on the secondary side of the liquid phase chamber 5 (primary side of the booster pump 7) is lower than the pressure in the liquid phase chamber 5, and in some cases, higher than the pressure in the main pipe of the water supply destination device, particularly the cleaning device. It gets lower. The operation is performed so that the water pressure on the secondary side of the liquid phase chamber 5 is higher than the air supply pressure to the gas phase chamber 4. The water flow pressure loss (water flow pressure loss between the installation location of the pressure sensor P4 and the installation location of the pressure sensor P2) in the piping and equipment on the primary side of the booster pump 7 is preferably 100 kPa or less, more preferably 50 kPa or less. It is preferable to design and operate as such.

[Discharge pressure of booster pump 7 (pressure sensor P3)]
The degree of boosting by the booster pump 7 is the received pure water pressure (measured value of the pressure sensor P4), the water pressure on the secondary side of the liquid phase chamber 5 (measured value of the pressure sensor P2), the amount of water to be sent, and the requirements of the water supply destination device. Although it depends on the water pressure (particularly, the pressure in the main pipe in the cleaning device), it is often about 50 to 300 kPa.

[Difference between the air supply pressure to the membrane module gas phase chamber and the water pressure of the gas-dissolved water]
The difference between the air supply pressure to the membrane module gas phase chamber and the water pressure of the gas-dissolved water is preferably 30 kPa or more. For example, the difference between the air supply pressure to the gas phase chamber 4 and the water pressure on the secondary side of the liquid phase chamber 5 is preferably 30 kPa or more. Further, it is preferable that the difference between the air supply pressure to the gas phase chamber 4 and the pressure in the main pipe of the semiconductor component cleaning device 100 is 30 kPa or more.

[Boost pump on the primary side of the membrane module]
In addition to the booster pump on the secondary side of the liquid phase chamber, a booster pump for boosting the received pure water can be provided on the primary side (line L1 in FIGS. 1 and 2) of the liquid phase chamber of the membrane module. As a result, the relationship of equation (1) is maintained at the outlet of the liquid phase chamber, and the gas is dissolved by increasing the supply pressure to the gas dissolution film module while avoiding the ejection of gas from the gas phase side to the liquid phase side of the gas dissolution film. It becomes easier to increase the gas concentration. The pump on the primary side of the liquid phase chamber can be effectively used even when the pressure of the received pure water to the gas-dissolved water production apparatus is low or when the flow rate fluctuation of the received pure water is large.

[About foaming due to pressure loss]
Even if the gas-dissolved water does not contain bubbles at the gas-dissolved water outlet of the gas-dissolved water production apparatus, for example, bubbles may be mixed in the gas-dissolved water in the main pipe of the cleaning apparatus for semiconductor parts. If air bubbles are mixed in, cleaning defects may occur due to adhesion of air bubbles to the surface of the object to be cleaned, poor ultrasonic propagation to the gas-dissolved water in the cleaning tank, and the like. In addition, there is a possibility that the flow rate measurement cannot be performed correctly due to the adhesion of air bubbles to the flow rate sensor in the cleaning device, or the water pressure fluctuation in the pressure adjusting section in the main pipe becomes large.

The cause of air bubbles being mixed in the main piping of the cleaning device is a decrease in water pressure that occurs between the gas-dissolved water production device and the cleaning device. The gas-dissolved water production device may be placed adjacent to the cleaning device, but in many cases, the cleaning device is installed in a clean room with high cleanliness, and the gas-dissolved water production device is installed in the equipment room with slightly low cleanliness. Is installed. The equipment room is often located on the lower floor or annex of the clean room, so there is a pressure loss between the gas-dissolved water production equipment and the cleaning equipment, for example, due to a pipe length of several tens of meters or more and a height difference of about 10 m. The pressure of the gas-dissolved water in the main pipe of the cleaning device may be much lower than the outlet water pressure of the gas-dissolved water production device.

Even if the relationship of equation (1) is established at the liquid phase chamber outlet of the membrane module, the pressure loss in the gas-dissolved water production equipment and the pressure loss in the connecting pipe between the gas-dissolved water production equipment and the cleaning equipment (friction loss and water head). When the gas-dissolved water pressure drops due to the pressure loss in the main pipe of the cleaning device, the pressure becomes "the air supply pressure to the membrane module gas phase chamber ≒ the water pressure of the gas-dissolved water". May foam in the main pipe.

For example, a facility having the configuration shown in FIG. 1 (however, the booster pump is installed on the primary side instead of the secondary side of the liquid phase chamber, and the height difference between the gas-dissolved water production device and the cleaning device is about 10 m). In one example, there is the following pressure loss.
Piping friction loss from outlet 5 of liquid phase chamber to outlet 1 of gas-dissolved water production equipment: 0.05 MPa,
Positional head loss from gas-dissolved water production device 1 to cleaning device 100: 0.10 MPa,
Piping friction loss from gas-dissolved water production device 1 to cleaning device 100: 0.04 MPa,
Friction loss of main piping in cleaning device 100: 0.01 MPa.

According to this example, the pressure loss from the outlet of the liquid phase chamber 5 to the main pipe in the cleaning device is 0.2 MPa. If the water pressure at the outlet of the liquid phase chamber 5 satisfies the relationship of the formula (1), the gas-dissolved water does not contain bubbles. However, if the value of the pressure difference of "(water pressure of gas-dissolved water)-(air supply pressure to the membrane module gas phase chamber 4)" at the outlet of the liquid phase chamber 5 is smaller than 0.2 MPa, the main pipe of the cleaning device In, the relationship of the formula (1) is not maintained, and there is a possibility that the gas-dissolved water contains air bubbles.

In consideration of such a pressure loss, the outlet water pressure of the gas dissolved water production apparatus 1 can be set higher than the water pressure received by the cleaning apparatus, and the pressure difference can be set to exceed, for example, 0.2 MPa. The present invention is very effective in such cases.

[About foaming caused by fluctuations in water volume]
The amount of water used in the destination device may fluctuate, and therefore the amount of water supplied from the gas-dissolved water production device to the water-destination device may fluctuate, resulting in foaming of the gas-dissolved water. For example, when the water supply destination device is a cleaning device for semiconductor parts, a method of directly applying cleaning water (gas-dissolved water) to the object to be cleaned (hereinafter, may be referred to as "single-wafer cleaning type") or using cleaning water. A method of immersing the object to be cleaned in a filled cleaning tank for cleaning (hereinafter, may be referred to as "batch cleaning type") is adopted. In either case, the flow rate of the washing water from the washing water discharge port (the washing water is discharged toward the object to be washed or toward the washing tank) is the valve (V101) installed in the washing water discharge system (line L104). ) Is adjusted to a predetermined amount.

In the cleaning device, regardless of whether it is a single-wafer cleaning type or a batch cleaning type, water discharge is executed and stopped by opening and closing an automatic on-off valve (V101) installed in the cleaning water discharge system. When a plurality of cleaning chambers or cleaning tanks are provided, automatic on-off valves are provided for each cleaning chamber or cleaning tank, and each automatic on-off valve often operates independently. Therefore, the total amount of washing water that contributes to washing will fluctuate. If there are many automatic on-off valves in the open state among the plurality of automatic on-off valves, the total amount of washing water increases, the water pressure decreases, and the flow rate from each discharge system decreases. On the other hand, if there are many automatic on-off valves in the closed state, the total amount of washing water decreases, the water pressure rises, and the flow rate from each discharge system rises. The present invention is also very effective in such cases.

As the automatic on-off valve V101, a valve capable of both adjusting the flow rate and opening / closing may be used, or separate valves having their respective functions may be used. In the case of the single-wafer cleaning type, a sackback valve may be provided to prevent dripping from the washing water discharge port immediately after the on-off valve is closed.

[Hunting prevention]
When a plurality of pressure adjusting mechanisms are installed in the same piping system, each of them independently adjusts the pressure, and as a result, hunting may occur and the water pressure in the cleaning device master pipe may become unstable. For example, when the gas-dissolved water is supplied from the gas-dissolved water production device 1 to the cleaning device provided with the back pressure valve (pressure monitoring and adjusting mechanism 105) as described with reference to FIG. 3, the inside of the gas-dissolved water production device 1. Hunting may be a concern when adjusting the pressure with. In such a case, the booster pump 7 mounted on the gas-dissolved water production apparatus 1 performs only boosting by, for example, keeping the rotation speed constant (the boosting width of the booster pump is substantially constant), and the pressure fluctuates. It can be operated without following control.

[Gas dissolution membrane]
As the membrane module, a hollow fiber membrane module filled with a hollow fiber membrane that can easily secure a wide membrane area is widely used. Since some of them have low water pressure resistance, when installing a booster pump on the primary side of the gas phase chamber of the membrane module, operate the booster pump so that the water pressure resistance of the membrane is not exceeded.

When the flow rate of the gas-dissolved water to be produced is large, the water flow pressure loss can be suppressed low by arranging a plurality of membrane modules in parallel. One for ozone (O ₃₎ Among gas dissolving membrane module is one although lower water pressure, through water pressure loss because of inner pressure (water inside the hollow fiber membrane, the air supply to the outside) is also large. Table 1 shows an example of a commercially available membrane module used for producing gas-dissolved water for cleaning semiconductor parts.

According to the present invention, even when the gas-dissolved water is sent to a place far away from the gas-dissolved water production apparatus, it is easy to suppress the mixing of bubbles into the gas-dissolved water. Further, it is easy to increase the water pressure of the gas-dissolved water supplied to the water supply destination device and suppress the decrease in the dissolved gas concentration in the gas-dissolved water due to foaming.

If the water pressure of pure water (line L1) received in the gas-dissolved water production device exceeds the water pressure resistance of components such as valves, membrane modules, and water quality measuring instruments that make up the gas-dissolved water production device, the pressure is appropriately reduced. A valve can be installed to reduce the water pressure of pure water and protect the components.

1 Gas dissolution water production equipment 2 Gas dissolution membrane module 3 Gas dissolution membrane 4 Gas phase chamber 5 Liquid phase chamber 6 Dissolved ozone concentration meter 7 Booster pump 8 Dissolved hydrogen concentration meter 11, 12, 13 Mass flow controller 14 Ozone gas generator 15 Excess ozone gas Decomposition catalyst cylinder 21 Hydrogen gas generator 100 Water supply destination device (cleaning device)
101 Cleaning chamber 102 Nozzle 103 Substrate 104 Turntable 105 Pressure monitoring and adjustment mechanism 106 Ozone decomposer V1, V2, V5, V6, V21 On-off valve V3 Air supply pressure adjustment valve V101 Valve with flow rate adjustment mechanism P1 to P4 Pressure sensor F1, F2, F101 Flow sensor

Claims (10)

A gas-dissolved water production apparatus for producing gas-dissolved water by dissolving gas in water to be treated, which includes a gas-dissolved membrane module including a gas-phase chamber and a liquid-phase chamber partitioned by a gas-dissolved membrane.
A gas-dissolved water production apparatus including a step-up pump for boosting the pressure of the gas-dissolved water, which is installed on the secondary side of the liquid phase chamber. A first pressure sensor for monitoring the air supply pressure to the gas phase chamber and
A second pressure sensor for monitoring the water pressure on the primary or secondary side of the liquid phase chamber, and
The supply air pressure adjusting means for adjusting the supply pressure to the gas phase chamber to a pressure lower than the water pressure on the secondary side of the liquid phase chamber is included.
When the second pressure sensor monitors the water pressure on the primary side of the liquid phase chamber, the calculation means is further included, and the calculation means is the pressure in the liquid phase chamber from the water pressure on the primary side of the liquid phase chamber. The gas-dissolved water production apparatus according to claim 1, which is a means for obtaining the water pressure on the secondary side of the liquid phase chamber by subtracting the loss. The gas dissolution film module has a structure in which the liquid phase chamber is formed inside the hollow fiber membrane and the gas phase chamber is formed outside.
The gas-dissolved water production apparatus according to claim 1 or 2, wherein the gas contains ozone gas. The wetted parts of the booster pump are polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, polychlorotrifluoroethylene and ethylene / tetrafluoroethylene copolymer. The gas-dissolved water production apparatus according to any one of claims 1 to 3, which is formed of at least one selected from the group consisting of. It is a gas-dissolved water production device for producing gas-dissolved water used in a cleaning device for semiconductor parts.
Any of claims 1 to 4, including a discharge pressure adjusting means for adjusting the discharge pressure of the booster pump so that the pressure in the main pipe in the cleaning device is higher than the supply pressure to the gas phase chamber. The gas-dissolved water production apparatus according to item 1. A gas-dissolved water production method for producing gas-dissolved water by dissolving gas in water to be treated using a gas-dissolved membrane module having a gas-phase chamber and a liquid-phase chamber partitioned by a gas-dissolved membrane.
A method for producing gas-dissolved water, which comprises a step of boosting the pressure of the gas-dissolved water by using a pressure-pressing pump installed on the secondary side of the liquid phase chamber of the gas-dissolved film module. A first pressure detection step for monitoring the air supply pressure to the gas phase chamber, and
A second pressure detection step for monitoring the water pressure on the primary or secondary side of the liquid phase chamber, and
The supply air pressure adjusting step of adjusting the air supply pressure to the gas phase chamber to a pressure lower than the water pressure on the secondary side of the liquid phase chamber is included.
When monitoring the water pressure on the primary side of the liquid phase chamber in the second pressure detection step, a calculation step is further included, and the calculation step is performed in the liquid phase chamber from the water pressure on the primary side of the liquid phase chamber. The method for producing gas-dissolved water according to claim 6, which is a step of obtaining the water pressure on the secondary side of the liquid phase chamber by subtracting the pressure loss. The gas dissolution film module has a structure in which the liquid phase chamber is formed inside the hollow fiber membrane and the gas phase chamber is formed outside.
The method for producing gas-dissolved water according to claim 6 or 7, wherein the gas contains ozone gas. The wetted parts of the booster pump are polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, polychlorotrifluoroethylene and ethylene / tetrafluoroethylene copolymer. The method for producing gas-dissolved water according to any one of claims 6 to 8, which is formed by at least one selected from the group consisting of. A method for producing gas-dissolved water used in a cleaning device for semiconductor parts.
Any of claims 6 to 9, which includes a discharge pressure adjusting step of adjusting the discharge pressure of the booster pump so that the pressure in the main pipe in the cleaning device is higher than the supply pressure to the gas phase chamber. The method for producing gas-dissolved water according to item 1.

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