JPH1177021A - Supplier for hydrogen-containing high-purity water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply hydrogen-containing high purity water of a stable dissolved hydrogen gas concentration even in the case wherein a water use amount is fluctuated without discarding the hydrogen-containing high purity water for washing because of generating a surplus. SOLUTION: In a washing process using hydrogen-containing high purity water, (A) a closed type water tank 7 holding hydrogen containing high-purity water not used at a use point and high-purity water to be supplied, (B) a conveying pump 8, (C) a degassing part 9 removing dissolved gas of water, (D) a dissolution part 16 dissolving hydrogen gas in water after degassing; or (A') a degassing part removing dissolved gas in the high-purity water to be supplied, (B') a dissolution part dissolving hydrogen gas into the water after degassing, (C') a closed type water tank holding prepared hydrogen-containing high-purity water and the hydrogen-containing high-purity water not used at the use point, (D') the conveying pump; and (E) a filter 20, and (F) a circulating pipeline system 6 returning to the water tank are provided, and a necessary amount of the hydrogen-containing high-purity water is supplied at the use point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydrogen-containing ultrapure water supply apparatus. More specifically, the present invention relates to a method of discharging ultra-pure water in which hydrogen gas is dissolved in an electronic material cleaning step without causing a substantial change in the concentration of dissolved hydrogen gas, and unused hydrogen-containing ultra-pure water. The present invention relates to a hydrogen-containing ultrapure water supply apparatus capable of supplying a required amount of hydrogen-containing ultrapure water having a desired dissolved hydrogen gas concentration to a point of use without using excess hydrogen gas.

[0002]

2. Description of the Related Art Conventionally, cleaning of a silicon substrate for a semiconductor, a glass substrate for a liquid crystal, and the like is mainly performed by using a mixed solution of hydrogen peroxide solution and sulfuric acid, a mixed solution of hydrogen peroxide solution, hydrochloric acid and water, and a hydrogen peroxide solution. Cleaning has been performed at a high temperature using a concentrated chemical solution based on hydrogen peroxide, such as a mixed solution of ammonia water and water, followed by rinsing with ultrapure water, that is, the so-called RCA cleaning method. The RCA cleaning method is an effective method for removing metal components on the semiconductor surface, but also removes fine particles attached to the semiconductor surface. However, in such a method, the cost of the chemical solution is high because a large amount of hydrogen peroxide solution, high-concentration acid, alkali and the like are used, and further, the cost of ultrapure water for rinsing, the cost of waste liquid treatment, and the exhaust of chemical vapor are exhausted. A large cost is required, such as an air conditioning cost for newly preparing clean air. In recent years, the wet cleaning process has been reviewed in order to reduce these costs and to reduce the burden on the environment such as mass use of water, mass disposal of drugs, and emission of exhaust gas. The present inventors have found that among the impurities to be removed in the wet cleaning step, the fine particles, which are particularly considered to have a significant effect on the performance of electronic components, are extremely effectively treated with ultrapure water in which hydrogen gas is dissolved. Found to be removed,
As a method that can obtain a high cleaning effect at room temperature using low concentration chemicals, a cleaning method for electronic materials using hydrogen-containing ultrapure water was developed. In order to apply this method to a manufacturing site that cleans a large number of substrates, the hydrogen-containing ultrapure water can be handled safely and freely, and the desired dissolved hydrogen gas concentration can be adjusted according to the fluctuation of the hydrogen-containing ultrapure water consumption. There has been a demand for a hydrogen-containing ultrapure water supply apparatus capable of stably supplying a required amount of the hydrogen-containing ultrapure water to the point of use.

[0003]

SUMMARY OF THE INVENTION The present invention provides a hydrogen-containing ultrapure water for cleaning without a surplus being generated and discarding the hydrogen-containing ultrapure water having a stable dissolved hydrogen gas concentration even when the amount of used water fluctuates. An object of the present invention is to provide a hydrogen-containing ultrapure water supply device capable of supplying ultrapure water to a point of use.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, a degassing section for removing dissolved gas of ultrapure water and a gas supplied from a hydrogen gas supply section. Has a dissolving section that dissolves hydrogen gas in degassed water, and a closed water tank that holds mixed water of excess hydrogen-containing ultrapure water that is not used at the point of use and replenished ultrapure water. A system that sends hydrogen-containing ultrapure water to the point of use via a filter using a water pump, circulates unused hydrogen-containing ultrapure water and returns it to the water tank, and uses a constant amount of hydrogen-containing ultrapure water as needed It has been found that it can be supplied to points, and based on this finding, the present invention has been completed. That is, in the present invention, (1) in a cleaning step of an electronic material using hydrogen-containing ultrapure water, (A) mixed water of surplus hydrogen-containing ultrapure water not used at the point of use and ultrapure water to be replenished Holds a closed aquarium,
(B) a pump for feeding water held in a water tank, (C) a degassing unit for removing dissolved gas of water to be fed, and (D) water after degassing hydrogen gas supplied from a hydrogen gas supply unit. Has a dissolving part for dissolving in water, a (E) filter and a circulation piping system returning to the water tank via the (F) use point, and supplies the required amount of hydrogen-containing ultrapure water at the use point while circulating the hydrogen-containing ultrapure water. A hydrogen-containing ultrapure water supply device, and (2) a step of removing dissolved gas of the replenished ultrapure water in the step of cleaning the electronic material using the hydrogen-containing ultrapure water. Gas part, (B) a dissolving part for dissolving the hydrogen gas supplied from the hydrogen gas supply part in degassed water,
(C) A closed water tank for holding the hydrogen-containing ultrapure water prepared in the melting section and the surplus hydrogen-containing ultrapure water not used at the point of use, and (D) sending hydrogen-containing ultrapure water from the water tank. It has a pump, an (E) filter and a circulation piping system returning to the water tank via the (F) use point, and supplies the required amount of hydrogen-containing ultrapure water at the use point while circulating the hydrogen-containing ultrapure water. A hydrogen-containing ultrapure water supply device. Further, according to a preferred embodiment of the present invention, (3) the gas phase portion of the closed water tank is controlled according to the fluctuation of the water level and the amount of permeation and emission of the dissolved hydrogen gas through the member wall of the circulation system between the water tank and the use point. (2) the hydrogen-containing ultrapure water supply device according to (2), which can replenish hydrogen gas and exhaust the gaseous phase so as to maintain the atmospheric pressure. A mechanism that measures the concentration of dissolved hydrogen gas downstream of the dissolving unit that dissolves hydrogen gas in water, and adjusts the valve opening of the hydrogen gas supply pipe to supply hydrogen gas in an amount that compensates for the shortage of the predetermined concentration. (1) The hydrogen-containing ultrapure water supply device according to (1) or (2), (5) the hydrogen according to (1) or (2), which has a mechanism for adding a high-purity chemical. (6) The high purity chemical to be added is a high purity ammonia water. Feeder of the hydrogen-containing ultrapure water according,
(7) Water on the downstream side of the degassing section for removing dissolved gas
The supply device of the hydrogen-containing ultrapure water according to the above item (1) or (2), which has a mechanism for measuring the pH and adding high-purity aqueous ammonia to a predetermined pH value, (8) a liquid contact member (1) or (2), wherein the hydrogen-containing ultrapure water supply device is a material having high purity and low gas permeability, and (9) the liquid contact member is polyvinylidene fluoride resin or clean poly. The hydrogen-containing ultrapure water supply device according to the above item (1) or (2), which is a vinyl chloride resin, can be used.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A hydrogen-containing ultrapure water supply apparatus according to the present invention comprises the steps of: dissolving hydrogen gas in ultrapure water to obtain a desired dissolved hydrogen gas concentration; It is a device that supplies to the point of use. The ultrapure water used in the present invention is high-purity water having an electrical conductivity of about 6 μS / m at 25 ° C. The method for producing ultrapure water used in the present invention is not particularly limited, and it can be produced by a known process. FIG. 1 is a process system diagram showing an example of a secondary pure water process in the production of ultrapure water. The primary pure water treated in the pretreatment step and the primary pure water step is supplied to the water tank 1 filled with high-purity nitrogen gas in order to prevent contamination from outside air. The pure water in the water tank is sequentially sent by a pump 2 to an ultraviolet irradiation device 3, an ion exchange device 4, and an ultrafiltration device 5. Pure water is irradiated with ultraviolet light in an ultraviolet irradiation device to decompose and sterilize a small amount of organic carbon in water, remove a small amount of ionic substances in an ion exchange device, and remove a minute amount of fine particles in an ultrafiltration device. Is removed to become ultrapure water. The ultrapure water produced in the secondary pure water process is sent to each use point and used. Since the hydrogen-containing ultrapure water supplied by the apparatus of the present invention is used for cleaning electronic components and the like, it is preferable to use ultrapure water purified in the secondary pure water process as raw water. Ultrapure water produced by passing through an ultraviolet irradiation device, an ion exchange device and an ultrafiltration device is branched from the ultrapure water loop pipe and sent to the device of the present invention via a replenishment ultrapure water line. Can be.

FIG. 2 is a process flow chart of the first embodiment of the apparatus of the present invention. In this embodiment, surplus hydrogen-containing ultrapure water not used at the point of use is returned to the closed water tank 7 by the circulation piping system 6. Further, the closed type water tank is supplied with ultrapure water in an amount corresponding to the hydrogen-containing ultrapure water used at the point of use from a separately provided secondary pure water process. The closed water tank holds a mixed water of surplus hydrogen-containing ultrapure water and ultrapure water to be replenished that has not been used at the point of use. The closed water tank is preferably filled with high-purity nitrogen gas in order to prevent contamination from outside air. The mixed water held in the water tank is sent by a water pump 8 to a deaeration unit 9 for removing dissolved gas of water. Although there is no particular limitation on the mechanism of the degassing unit, it is preferable to employ vacuum degassing or decompression film degassing capable of removing gas dissolved in water. Among them, membrane deaeration by a high-purity deaeration membrane module is particularly close to the point of use, because dissolved gas can be efficiently deaerated without impairing the purity of ultrapure water, It can be suitably used. In the degassing membrane module, ultrapure water comes into contact with the gas side via the gas permeable membrane, and the gas side is kept in a reduced pressure state by the vacuum pump 10. There is no particular limitation on the gas permeable membrane of the degassing membrane module. For example, polypropylene, polydimethylsiloxane, polycarbonate-polydimethylsiloxane block copolymer, polyvinylphenol-polydimethylsiloxane-polysulfone block copolymer, poly (4-
Polymer films such as methylpentene-1), poly (2,6-dimethylphenylene oxide), and polytetrafluoroethylene can be given.

[0007] High purity chemicals can be added to the hydrogen-containing ultrapure water supplied by the apparatus of the present invention, if necessary. There is no particular limitation on the method of adding the high-purity chemical. For example, the high-purity chemical can be added in proportion to the amount of ultrapure water to be supplied to the apparatus, or the water quality is measured, and the high-purity chemical is measured according to the water quality. The amount of the pure chemical added can be controlled. It is preferable to add high-purity ammonia water to the hydrogen-containing ultrapure water to make it alkaline, in order to increase the cleaning power of the hydrogen-containing ultrapure water. The amount can be proportional to the amount, or
It is also possible to measure the pH of water and add high-purity aqueous ammonia to a predetermined pH value. For example, on the downstream side of the degassing section, the pH is measured by the pH sensor 11, a signal is sent from the pH controller 12 to the pump 13,
4 to a predetermined amount of high-purity ammonia water can be added. The high-purity aqueous ammonia is preferably added downstream of the degassing section in order to avoid loss of ammonia due to degassing. The addition position of the high-purity ammonia water can be further downstream of the dissolving section or immediately before the use point. The addition amount may be individually set according to the necessity at each use point. The water from which the dissolved gas has been removed in the deaeration section is then supplied to the hydrogen gas supply section 15.
Is sent to the dissolving section 16 for dissolving the hydrogen gas supplied from. The hydrogen gas supply unit is not particularly limited as long as it can supply high-purity hydrogen gas that can maintain the same purity as ultrapure water, for example, a high-purity hydrogen gas cylinder or ultrapure water as raw water An apparatus for generating hydrogen gas by electrolysis can be used. By passing degassed ultrapure water to the liquid side of the gas permeable membrane and supplying hydrogen gas to the gas side, the hydrogen gas moves into the ultrapure water via the gas permeable membrane and dissolves.

In the apparatus of the present invention, the amount of hydrogen gas dissolved in degassed water is preferably at least 0.7 mg / liter. If the amount of the dissolved hydrogen gas is 0.7 mg / liter or more, the hydrogen-containing ultrapure water exhibits a sufficient detergency in the step of cleaning the electronic material. The amount of dissolved hydrogen gas in water at 20 ° C. under atmospheric pressure is 1.6 mg / liter. Therefore, when the amount of dissolved hydrogen gas is expressed as a ratio to the saturated dissolved amount, that is, as the degree of saturation, the dissolved amount of hydrogen gas is expressed as 0.7 mg / liter corresponds to about 0.45 times the saturation of dissolved hydrogen gas. In order to make the degree of saturation of the dissolved hydrogen gas 0.45 times or more, it is preferable to perform degassing in the degassing section so that the degree of saturation of the dissolved gas of water becomes less than 0.55 times. By setting the degree of saturation of the dissolved gas in water to less than 0.55 times, a vacancy of the gas dissolving capacity of 0.45 times or more of saturation occurs in the water, and hydrogen gas can be easily dissolved in the dissolving portion. . Since 19.2 mg / liter of nitrogen gas is dissolved in water in equilibrium with nitrogen gas at 20 ° C., the amount of nitrogen gas dissolved in water by degassing is reduced by about 1%.
By making the amount less than 0.6 mg / liter, the saturation is reduced to 0.6.
It can be less than 55 times. In the apparatus of the present invention, the dissolved hydrogen gas concentration of the ultra-pure hydrogen-containing water in which the hydrogen gas is dissolved is measured, and the hydrogen gas supplied to the dissolving unit is adjusted to a predetermined value according to the measured value. Can be controlled. For example, a dissolved hydrogen gas concentration sensor 17 is provided downstream of the melting section to measure the dissolved hydrogen gas concentration of hydrogen-containing ultrapure water, and a signal is sent from the dissolved hydrogen gas concentration controller 18 to the supply control section 19 of the hydrogen gas supply pipe. And the amount of hydrogen gas supplied can be controlled by adjusting the valve opening and the like. The dissolved hydrogen gas concentration sensor
It can be provided directly on the main pipe, or it can be provided on a partly branched measurement dedicated pipe. In addition, when a steady operation is performed, the flow rate of water and the concentration of dissolved gas in the dissolving section are constant, so that the supply amount of hydrogen gas can be constant.

In the apparatus of the present invention, the mechanism of the dissolving section for dissolving the hydrogen gas is not particularly limited, and any contacting method such as bubbling, in-line mixing, or use of a gas-permeable membrane module can be used. Among them, the amount of hydrogen gas dissolved per unit time and space is large, and the purity of water can be maintained at a level that can be used for wet cleaning of electronic materials, and the dissolution efficiency of hydrogen gas can be easily increased. A pure gas permeable membrane module is preferred. There is no particular limitation on the gas permeable membrane of the high-purity gas permeable membrane module.For example, polypropylene, polydimethylsiloxane, polycarbonate-polydimethylsiloxane block copolymer, polyvinylphenol-polydimethylsiloxane-polysulfone block copolymer, poly ( Polymer films such as 4-methylpentene-1), poly (2,6-dimethylphenylene oxide), and polytetrafluoroethylene can be given. In the apparatus of this embodiment, the ultrapure water containing hydrogen in which the hydrogen gas is dissolved in the dissolving section is sent to a use point after removing fine particles by the filter 20. The material of the filter is not particularly limited, and examples thereof include a porous membrane such as a microfiltration membrane and an ultrafiltration membrane. The pore size of the porous membrane is
It is preferably at most 2 μm, more preferably at most 0.1 μm. The required amount of the ultra-pure hydrogen-containing water sent to the use point is used at the use point, and the surplus hydrogen-containing ultra-pure water not used is returned to the closed water tank 7 via the circulation piping system 6. Used again, mixed with replenished ultrapure water. The hydrogen-containing ultrapure water supply device of the present embodiment mixes the surplus hydrogen-containing ultrapure water with the newly supplied ultrapure water, and once substantially removes the dissolved gas containing hydrogen gas in the degassing section. Since the hydrogen gas is dissolved again in the dissolving section, the apparatus can be steadily operated with the hydrogen-containing ultrapure water having a stable water quality.

FIG. 3 is a process flow chart of a second embodiment of the apparatus of the present invention. In this embodiment, the replenished ultrapure water is
It is sent directly to the degassing section 21 for removing dissolved gas of water.
Although there is no particular limitation on the mechanism of the degassing unit, it is preferable to employ vacuum degassing or vacuum degassing capable of removing nitrogen gas, oxygen gas, and the like dissolved in water. Among these, membrane degassing by a high-purity degassing membrane module is particularly close to the point of use, because it can degas a small amount of dissolved gas without impairing the purity of ultrapure water, It can be suitably used. In the degassing membrane module, ultrapure water comes into contact with the gas side via the gas permeable membrane, and the gas side is kept in a reduced pressure state by the vacuum pump 22. There is no particular limitation on the gas permeable membrane of the degassing membrane module, and the polymer membrane described above can be used.

[0011] The hydrogen-containing ultrapure water supplied by the apparatus of the present invention may contain a high-purity chemical as required. There is no particular limitation on the method of adding the high-purity chemical. For example, the high-purity chemical can be added in proportion to the amount of ultrapure water to be supplied to the apparatus, or the water quality is measured, and the high-purity chemical is measured according to the water quality. The amount of the pure chemical added can be controlled. It is preferable to add high-purity ammonia water to the hydrogen-containing ultrapure water to make it alkaline, in order to increase the cleaning power of the hydrogen-containing ultrapure water. The amount can be proportional to the amount, or
It is also possible to measure the pH of water and add high-purity aqueous ammonia to a predetermined pH value. For example, on the downstream side of the degassing unit, the pH is measured by the pH sensor 23, a signal is sent from the pH controller 24 to the pump 25,
6 to a predetermined amount of high-purity ammonia water can be added. The addition position of the high-purity ammonia water can be further downstream of the dissolving section or immediately before the use point. The water from which the dissolved gas has been removed in the degassing section is then
The hydrogen gas supplied from the hydrogen gas supply unit 27 is sent to a dissolving unit 28 that dissolves the hydrogen gas. The hydrogen gas supply unit is not particularly limited as long as it can supply high-purity hydrogen gas that can maintain the same purity as ultrapure water, for example, a high-purity hydrogen gas cylinder or ultrapure water as raw water An apparatus for generating hydrogen gas by electrolysis can be used. By passing degassed ultrapure water to the liquid side of the gas permeable membrane and supplying hydrogen gas to the gas side, the hydrogen gas moves into the ultrapure water via the gas permeable membrane and dissolves.

In the apparatus of the present invention, the dissolved hydrogen gas concentration of hydrogen-containing ultrapure water in which hydrogen gas is dissolved is measured, and the dissolved hydrogen gas concentration is supplied to the dissolving section so that the dissolved hydrogen gas concentration becomes a predetermined value according to the measured value. The amount of hydrogen gas generated can be controlled. For example, a dissolved hydrogen gas concentration sensor 29 is provided downstream of the melting unit to measure the dissolved hydrogen gas concentration of the hydrogen-containing ultrapure water, and a signal is sent from the dissolved hydrogen gas concentration controller 30 to the supply control unit 31 of the hydrogen gas supply pipe. And the amount of hydrogen gas supplied can be controlled by adjusting the valve opening and the like. The dissolved hydrogen gas concentration sensor can be provided directly on the main pipe, or can be provided on a partly branched measurement dedicated pipe. In addition, when a steady operation is performed, the flow rate of water and the concentration of dissolved gas in the dissolving section are constant, so that the supply amount of hydrogen gas can be constant. In the apparatus of the present invention, the mechanism of the dissolving section for dissolving the hydrogen gas is not particularly limited, and as described above, any contact method such as bubbling, in-line mixing, or use of a gas permeable membrane module can be used. In the apparatus of this embodiment, the hydrogen-containing ultrapure water in which the hydrogen gas has been dissolved in the dissolving section is sent to the closed water tank 32. Excess hydrogen-containing ultrapure water not used at the point of use is also returned to the closed water tank by the circulation piping system 33. In other words, the closed water tank was not used at the point of use, with the hydrogen-containing ultrapure water prepared from the newly supplied ultrapure water corresponding to the hydrogen-containing ultrapure water used at the point of use. Excess hydrogen-containing ultrapure water mixed water is retained. It is preferable that a hydrogen gas supply pipe 34 be provided in the closed water tank to supply hydrogen gas to the hydrogen-containing ultrapure water in the water tank in accordance with a change in water level. A dissolved hydrogen gas concentration sensor 35 is provided on the downstream side of the water tank to measure the dissolved hydrogen gas concentration of the ultrapure hydrogen-containing water sent out from the water tank. To control the amount of supplied hydrogen gas by adjusting the valve opening and the like. Also,
It is preferable to provide an exhaust device 38 in the closed water tank so that the gas phase can be kept at atmospheric pressure.

In the apparatus of the present invention, ultrapure water containing hydrogen in a closed water tank is sent to a use point after removing fine particles with a filter 40 by a pump 39. The material of the filter is not particularly limited, for example, a microfiltration membrane,
Examples include porous membranes such as ultrafiltration membranes. The pore diameter of the porous membrane is preferably 0.2 μm or less,
More preferably, it is 0.1 μm or less. The required amount of hydrogen-containing ultrapure water sent to the point of use is used at the point of use, and surplus hydrogen-containing ultrapure water that has not been used is returned to the closed water tank via the circulation piping system.
It is used again by mixing with hydrogen-containing ultrapure water prepared from the supplied ultrapure water. In this embodiment, hydrogen-containing ultrapure water prepared by dissolving hydrogen gas in replenished ultrapure water and excess hydrogen-containing ultrapure water not used at the point of use are mixed in a closed water tank. It is sent to the point of use through a pump and a filter. In this circulation system, the concentration of the dissolved hydrogen gas is reduced only by a very small amount of radiation permeating the pipes and the walls of the water tank, and does not substantially change in the order of several hours. In addition, the present embodiment has a mechanism capable of supplying hydrogen gas to the water tank, while also maintaining the dissolved hydrogen gas concentration for a long time and maintaining the gas phase pressure due to the decrease in the water level in the water tank. Hydrogen gas can be supplied on the water surface in conjunction with the gas pressure fluctuation or water level fluctuation in the gas phase in the water tank so that the ordinary ultrapure water tank is purged with high-purity nitrogen gas. A supply method of feeding and purging by a bubbling method is more preferable because dissolution of hydrogen gas becomes easy.

When the pressure of the gas phase in the closed water tank becomes higher than the atmospheric pressure, hydrogen gas having a saturation solubility at the atmospheric pressure or higher is dissolved. In this case, from the hydrogen-containing ultrapure water that has exited the use point and has been exposed to the atmospheric pressure, dissolved components having a saturation solubility or higher appear as bubbles. Air bubbles in the washing water are not desirable because they hinder uniform washing. In particular, when megahertz-band ultrasonic waves suitable for cleaning using hydrogen-containing ultrapure water are used together, bubbles tend to be generated due to the vibration,
Water in which hydrogen gas is dissolved at or above the saturation solubility under atmospheric pressure is not suitable. For this reason, it is preferable to attach an exhaust device for keeping the inside of the tank at atmospheric pressure, a barometer, and an automatic valve that opens and closes in conjunction with the exhaust device, at the top of the closed water tank. The hydrogen-containing ultrapure water supply device of the present embodiment is configured such that the hydrogen-containing ultrapure water not used at the point of use is supplied to the sealed water tank at a pressure lower than the atmospheric pressure by the supplied hydrogen gas in an amount corresponding to the water level fluctuation. Hydrogen gas is replenished in the range and then used in circulation, so the amount of hydrogen gas used and the energy required for degassing are kept to a minimum, and the dissolved hydrogen gas is stable even when the amount of water used fluctuates. Concentration of hydrogen-containing ultrapure water can be supplied. Hydrogen gas dissolved in ultrapure water does not decrease due to self-decomposition, so if strictly preventing leaks from joints and radiation permeating the walls of piping and water tank materials, even if circulation is repeated, Its concentration is maintained. In order to avoid danger due to the diffusion of hydrogen gas into the atmosphere, it is desirable to select piping and liquid-contact members that prevent hydrogen gas from permeating.

The liquid contact member of the apparatus of the present invention is preferably a material having high purity and low gas permeability. Examples of such a material include a polyvinylidene fluoride resin and a clean polyvinyl chloride resin.
So-called Teflon resins such as polytetrafluoroethylene resin and tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin are not suitable for use in the apparatus of the present invention because of their extremely high gas permeability. In the device of the present invention,
The supply of ultrapure water to the hydrogen-containing ultrapure water circulation system can be performed in conjunction with a water level meter that detects a decrease in the water level of a closed water tank by using the hydrogen-containing ultrapure water at the point of use. In the apparatus of the present invention, in order to simplify the degassing, chemical injection, and hydrogen dissolving steps, continuous water supply with a variable flow rate may be used, or intermittent water supply with a constant flow rate may be used. In this case, when the water level in the closed water tank drops to a predetermined level, the automatic supply valve of ultrapure water is opened in conjunction therewith, and the water is supplied at a constant flow rate. When degassing and dissolving hydrogen gas using the gas permeable membrane module, depressurize the degassing membrane module gas phase and start supplying hydrogen gas to the dissolved membrane module gas phase before starting the supply of ultrapure water. By doing so, it is possible to obtain hydrogen-containing ultrapure water having a predetermined dissolved hydrogen gas concentration from the beginning of ultrapure water replenishment. In the device of the present invention, hydrogen-containing ultrapure water can be stably supplied even if there is a fluctuation in the amount of hydrogen-containing ultrapure water used at the point of use.
It is preferable to set the circulation flow rate to be equal to or more than the maximum usage amount.

[0016]

According to the hydrogen-containing ultrapure water supply apparatus of the present invention, ultrapure water in which hydrogen gas has been dissolved in an electronic material cleaning step can be produced without substantially changing the dissolved hydrogen gas concentration. Without discharging unused hydrogen-containing ultrapure water,
In addition, a necessary amount of ultrapure water having a desired dissolved hydrogen gas concentration can be supplied to a use point without using more hydrogen gas than necessary.

[Brief description of the drawings]

FIG. 1 is a process flow diagram showing an example of a secondary pure water process in the production of ultrapure water.

FIG. 2 is a process flow chart of the first embodiment of the apparatus of the present invention.

FIG. 3 is a process flow chart of a second embodiment of the apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water tank 2 Pump 3 Ultraviolet irradiation apparatus 4 Ion exchange apparatus 5 Ultrafiltration apparatus 6 Circulation piping system 7 Sealed water tank 8 Water supply pump 9 Deaeration part 10 Vacuum pump 11 pH sensor 12 pH controller 13 Pump 14 Chemical liquid tank 15 Hydrogen gas Supply unit 16 Dissolution unit 17 Dissolved hydrogen gas concentration sensor 18 Dissolved hydrogen gas concentration controller 19 Supply amount control unit 20 Filter 21 Deaeration unit 22 Vacuum pump 23 pH sensor 24 pH controller 25 Pump 26 Chemical tank 27 Hydrogen gas supply unit 28 Dissolution unit 29 Dissolved hydrogen gas concentration sensor 30 Dissolved hydrogen gas concentration controller 31 Supply amount control unit 32 Sealed water tank 33 Circulation piping system 34 Hydrogen gas supply pipe 35 Dissolved hydrogen gas concentration sensor 36 Dissolved hydrogen gas concentration controller 37 Supply amount control unit 38 Exhaust Equipment 39 Pump 40 filter

Claims (2)

[Claims] (1) In a process of cleaning an electronic material using hydrogen-containing ultrapure water, (A) a hermetic seal for holding a mixture of surplus hydrogen-containing ultrapure water not used at a point of use and ultrapure water to be replenished. Water tank, (B) a pump for feeding water held in the water tank, (C) a degassing unit for removing dissolved gas of water to be fed, and (D) degassing hydrogen gas supplied from a hydrogen gas supply unit. It has a dissolving section for dissolving in air after the air, (E) a filter, and (F) a circulation piping system returning to the water tank via the use point. A hydrogen-containing ultrapure water supply device for supplying pure water. 2. In a cleaning step of an electronic material using hydrogen-containing ultrapure water, (A) a degassing section for removing a dissolved gas of replenished ultrapure water, and (B) hydrogen supplied from a hydrogen gas supply section. A dissolving unit for dissolving the gas in the degassed water, (C) a closed water tank for holding the hydrogen-containing ultrapure water prepared in the dissolving unit and excess hydrogen-containing ultrapure water not used at the point of use; (D) A pump that feeds hydrogen-containing ultrapure water from the water tank, (E) a filter, and (F) a circulation piping system that returns to the water tank via the use point, and is required at the use point while circulating the hydrogen-containing ultrapure water. A hydrogen-containing ultrapure water supply apparatus, which supplies an amount of hydrogen-containing ultrapure water.