JP4038940B2 - Ozone-dissolved water production equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for producing ozone-dissolved water. More specifically, the present invention removes a trace amount of ozone-decomposable substances contained in ultrapure water, and even if ozone-dissolved water is fed over a long distance, there is little decrease in ozone concentration, and the residual rate of dissolved ozone is high. The present invention relates to an apparatus for producing ozone-dissolved water capable of obtaining ozone-dissolved water.
[0002]
[Prior art]
Removing foreign materials from the surface of electronic materials such as silicon substrates for semiconductors, glass substrates for liquid crystals, quartz substrates for photomasks, etc. is extremely important for ensuring product quality and yield. Cleaning is widely performed. In order to remove organic contamination and metal contamination, it is effective to apply a cleaning solution with strong oxidizing power. Conventionally, a mixture of sulfuric acid and hydrogen peroxide (SPM cleaning solution), and a mixture of hydrochloric acid, hydrogen peroxide, and ultrapure water High temperature cleaning using a liquid (SC2 cleaning liquid) or the like has been adopted.
In recent years, there has been a demand for simplification of the cleaning process, resource saving, and room temperature, and even though the dissolved ozone concentration is about several mg / liter, it exerts extremely strong oxidizing power, causing organic matter contamination on the surface of electronic materials. Ozone-dissolved water that effectively removes metal contamination has been used for wet cleaning. Ozone-dissolved water is characterized in that when dissolved ozone decomposes, it simply returns to high-purity water. However, because dissolved ozone self-decomposes over time to produce oxygen gas, it is difficult to maintain and maintain the ozone concentration. Therefore, it was considered difficult to feed by long-distance piping. For this reason, ozone-dissolved water was produced in the vicinity of the cleaning device and used immediately.
On the other hand, the present inventors previously suppressed the decrease in ozone concentration by feeding the ozone-containing gas and ultrapure water while mixing them in the feed pipe, enabling long-distance feeding. As a result, the ozone dissolved water supply device shown in FIG. 1 was proposed. That is, a mixed gas of oxygen gas and a small amount of nitrogen gas is sent from the oxygen gas container 1 and the nitrogen gas container 2 to the silent discharge type ozone generator 3 to produce a mixed gas of ozone and oxygen gas. 4, it is fed into ultrapure water produced using an ion exchange device, a membrane device, an ultraviolet irradiation device or the like, using an ejector, a pump, or the like. The mixed gas of ozone and oxygen gas is mixed with ultrapure water to become a gas-liquid mixed state, ozone is dissolved in water to generate ozone-dissolved water, and further, the gas-liquid mixed fluid supply pipe is left in the gas-liquid mixed state Flowing through 5. Ozone dissolved in water becomes oxygen gas due to self-decomposition, but the decrease in ozone due to self-decomposition is compensated for by dissolving ozone in the gas phase into the water phase, so the ozone concentration in water is almost constant. Can be kept in. The ozone-dissolved water is taken out from the branch pipe 6 and separated at the use point 7 after being separated into gas and liquid. Excess ozone-dissolved water that has not been removed from the branch pipe is guided to the gas-liquid separator 8 and separated into a gas phase and an aqueous phase. Next, after decomposing ozone in the gas phase and the aqueous phase in the ozonolysis apparatuses 9 and 10, the gas phase is opened to the atmosphere as exhaust gas, and the water phase is recovered as waste water, subjected to necessary treatment and reused.
According to this ozone-dissolved water supply device, even when ozone-dissolved water is supplied over a long distance, ozone concentration fluctuation during the supply is small, and ozone-dissolved water having a substantially constant concentration can be supplied to the use point. it can. However, this apparatus requires an excess amount of ozone in order to compensate the decrease due to the self-decomposition of ozone in the ozone-dissolved water by dissolving ozone in the gas phase. For this reason, there is little ozone decomposition in ozone-dissolved water, and even if ozone-dissolved water is fed over a long distance, ozone-dissolved water with a low residual ozone residual rate is required with little decrease in ozone concentration during delivery. It became so.
[0003]
[Problems to be solved by the invention]
The present invention removes a trace amount of ozone-decomposable substances contained in ultrapure water, and reduces ozone concentration even when ozone-dissolved water is fed over a long distance, and ozone-dissolved water with a high residual rate of dissolved ozone. The object of the present invention is to provide a device for producing ozone-dissolved water that can be obtained.
[0004]
[Means for Solving the Problems]
As a result of intensive research to solve the above-mentioned problems, the present inventors have found that there is a trace substance that promotes the decomposition of ozone in ultrapure water that is the raw water of ozone-dissolved water. It has been found that it can be effectively removed by contacting with a reduction catalyst, and the present invention has been completed based on this finding.
That is, the present invention
(1) (A) ultrapure water supply pipe ultrapure water is supplied, (B) said ligated into ultrapure water supply pipe, OH radicals present in the ultrapure water, palladium for the removal of H radicals A catalyst packed tower in which a palladium-supported resin and an ion exchange resin coexisting with a redox catalyst comprising a supported resin and ultrapure water are contacted; and (C) a filtration for filtering ultrapure water passing through the catalyst packed tower Apparatus, (D) an ozone-dissolved water production apparatus characterized by having an ozone-dissolving apparatus that dissolves ozone in ultrapure water discharged from the filtration apparatus,
(2) The ozone-dissolved water according to item (1), wherein the catalyst packed tower is packed with a palladium-supported resin and a cation exchange resin or a palladium-supported resin, a cation exchange resin, and an anion exchange resin in a mixed state or a laminated state. Manufacturing equipment,
(3) The apparatus for producing ozone-dissolved water according to (1), wherein the catalyst packed tower is a palladium-supported resin tower and a cation exchange resin tower connected in series in this order;
(4) The apparatus for producing ozone-dissolved water according to (1), wherein the catalyst packed tower is a palladium-supported resin tower, a cation exchange resin tower, and an anion exchange resin tower connected in series in this order;
Is to provide.
Furthermore, as a preferred embodiment of the present invention,
(5) The apparatus for producing ozone-dissolved water according to (1), which has an ultrapure water feed pump in the front stage of the catalyst packed tower,
(6) The apparatus for producing ozone-dissolved water according to (5), wherein the ultrapure water feed pump is a booster pump,
(7) The apparatus for producing ozone-dissolved water according to item (1), wherein the catalyst packed tower is a palladium-supported resin tower and a mixed bed tower of a cation exchange resin and an anion exchange resin connected in series in this order.
(8) The apparatus for producing ozone-dissolved water according to (1), wherein the filtration device is a device provided with an ultrafiltration membrane (UF), a microfiltration membrane (MF) or a reverse osmosis membrane (RO),
(9) The apparatus for producing ozone-dissolved water according to item (1), wherein the ozone-dissolving apparatus is an ejector that directly contacts ultrapure water and an ozone-containing gas.
(10) The apparatus for producing ozone-dissolved water according to (9), which has a gas-liquid separator in the latter stage of the ejector,
(11) The apparatus for producing ozone-dissolved water according to item (1), wherein the ozone dissolving device is a gas permeable membrane module made of a fluororesin, and
(12) A device for producing ozone-dissolved water as set forth in (1), which has a chemical solution supply device and is provided with a chemical solution injection point in the preceding stage or subsequent stage of the filtration device,
Can be mentioned.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The apparatus for producing ozone-dissolved water of the present invention includes (A) an ultrapure water supply pipe to which ultrapure water is supplied, and (B) a catalyst that is connected to the ultrapure water supply pipe and makes the ultrapure water contact with a redox catalyst. A reaction unit, (C) a filtration device that filters the ultrapure water that has passed through the catalyst reaction unit, and (D) an ozone dissolution device that dissolves ozone in the ultrapure water discharged from the filtration device.
FIG. 2 is a process flow diagram of one embodiment of the apparatus of the present invention. In this embodiment, the ultrapure water is supplied to the ultrapure water supply pipe 12 by the ultrapure water feed pump 11. There is no restriction | limiting in particular in an ultrapure water feed pump, For example, a piston pump, a plunger pump, a booster pump, a turbine pump, a volute pump etc. can be mentioned. Among these, a booster pump can be suitably used. In order to obtain a practical ozone-dissolved water production apparatus, it is important to apply a certain amount of pressure to ultrapure water. When the ozone-containing gas is drawn into the ultrapure water passage pipe using the ejector, it is particularly necessary to increase the supply water pressure. If the pressure of ultrapure water supplied to the equipment is sufficiently high, there is no need for special measures, but there are more cases where this is not the case, so ultrapure water feed to increase the pressure of ultrapure water at the equipment inlet It is preferable to install a pump. The pressure of the supplied ultrapure water is preferably 0.2 to 0.5 MPa.
In the apparatus of the present invention, the ultrapure water supply pipe 12 is connected to a catalyst reaction unit 13 that brings ultrapure water into contact with a redox catalyst. There is no restriction | limiting in particular in the oxidation reduction catalyst used in this invention apparatus, For example, a platinum catalyst, a silver catalyst, a palladium catalyst etc. can be mentioned. Among these, a palladium catalyst can be particularly preferably used. As the palladium catalyst, in addition to metal palladium, palladium oxide, palladium hydride and the like, a catalyst in which palladium is supported on a carrier such as an ion exchange resin, alumina, activated carbon, or zeolite can be used. There is no restriction | limiting in particular in the shape of a palladium catalyst, For example, any shape, such as a powder form, a granular form, and a pellet form, can be used. An appropriate amount of the powdered catalyst can be added to the reaction tank provided in the reaction tank, or the catalyst can be filled in a reaction tower or the like and passed through as a fluidized bed. The granular or pellet-shaped catalyst can be packed in a reaction tower or the like to form a catalyst-packed tower, which can be continuously subjected to water flow treatment.
[0006]
In the case of a palladium supported catalyst, the supported amount of palladium is preferably 0.1 to 10% by weight. Among the palladium-supported catalysts, a palladium-supported resin in which palladium is supported on an anion exchange resin exhibits an excellent effect with a small amount of supported palladium, and can be particularly preferably used. A palladium-supported resin in which palladium is supported on an anion exchange resin can be prepared by filling an anion exchange resin in a reaction tower and passing an acidic solution of palladium chloride through water. Furthermore, by adding a reducing agent such as formalin to the reaction tower for reduction, a catalyst carrying metal palladium can be obtained. By bringing ultrapure water into contact with the oxidation-reduction catalyst in the catalytic reaction part, trace substances that promote the decomposition of ozone contained in the ultrapure water can be removed. Examples of trace substances that promote the decomposition of ozone include OH radicals and H radicals that are decomposition products of water generated by an ultraviolet irradiation device in an ultrapure water production system.
In the apparatus of the present invention, the palladium-carrying resin and the ion exchange resin can coexist in the catalyst packed tower. There are no particular restrictions on the coexistence of the palladium-supported resin and the ion-exchange resin. For example, the catalyst-packed tower is packed with a palladium-supported resin and a cation-exchange resin or a palladium-supported resin, a cation-exchange resin, and an anion-exchange resin in a mixed state or a stacked state. The palladium-supported resin tower and the cation exchange resin tower can be connected in series in this order, and the palladium-supported catalyst tower, the cation exchange resin tower and the anion exchange resin tower can be connected in series in this order, Alternatively, a palladium-supported catalyst tower and a mixed bed tower of a cation exchange resin and an anion exchange resin can be connected in series in this order. By coexisting a palladium-carrying resin and an ion exchange resin, even if a very small amount of palladium ion is eluted from the palladium-carrying resin, it can be captured by the ion exchange resin, and ion components are eluted from the ultrapure water feed pump. Even so, it can be captured by an ion exchange resin, and the high purity of ultrapure water can be maintained.
[0007]
In the apparatus of the present invention, ultrapure water that has passed through the catalytic reaction section is filtered by the filtering device 14. There is no restriction | limiting in particular in the filtration membrane used for a filtration apparatus, For example, an ultrafiltration membrane (UF), a microfiltration membrane (MF), a reverse osmosis membrane (RO) etc. can be mentioned. By filtering ultrapure water using a filtration device, the ultrapure water feed pump, palladium-carrying resin, cation exchange resin, anion exchange resin and other fine particles are removed to maintain the high purity of ultrapure water. can do.
In the apparatus of the present invention, the ozone-containing gas generated in the ozone generator 16 in the ozone dissolving device 15 is supplied to the ultrapure water discharged from the filtering device to dissolve the ozone. There is no particular limitation on the ozone dissolving device to be used, for example, a gas-permeable membrane module made of fluororesin having ozone resistance, a device for sucking ozone-containing gas such as an ejector, a gas dissolving pump, a bubbling device, etc. Can do. Among these, the ejector has a simple apparatus and can be preferably used. Dissolution of ozone can be promoted by providing an in-line mixer at the subsequent stage of the ejector and making the bubbles finer. When an ejector or a gas dissolving pump is used as the ozone dissolving device, it is in a gas-liquid mixed state of ozone-dissolved water and ozone-containing gas, so a gas-liquid separator 17 is provided in the subsequent stage to separate excess gas. It is preferable to obtain ozone-dissolved water that does not contain bubbles. Providing a proper capacity between the ozone dissolver and the gas-liquid separator to allow water passage time, thereby facilitating the dissolution of ozone and facilitating gas-liquid separation by promoting coalescence of fine bubbles. be able to.
There is no particular limitation on the ozone generator used in the apparatus of the present invention, for example, an apparatus for electrolyzing water to generate a mixed gas of ozone and oxygen gas, ozone and oxygen gas by silent discharge or creeping discharge using oxygen gas as a raw material An apparatus for generating a mixed gas of In order to obtain high-purity ozone-dissolved water, it is preferable to install a filter for capturing fine particles in the ozone-containing gas between the ozone generator and the ozone dissolver.
[0008]
In the device of the present invention, a chemical solution tank 18 and a chemical injection pump 19 are provided, and a chemical solution injection point is provided before or after the filtration device to inject a chemical solution such as acid or alkali. Instead of the chemical injection pump, it can be pumped by an inert gas such as nitrogen gas. The decomposition of dissolved ozone can be suppressed by injecting an acid to lower the pH. In this case, it is preferable from the aspect of maintaining the dissolved ozone concentration to inject the acid upstream of the ozone dissolving device. The cleaning effect of ozone-dissolved water can be enhanced by increasing the pH by injecting alkali. Examples of the alkali include ammonia and tetramethylammonium hydroxide. The ozone-dissolved water produced by using the apparatus of the present invention can measure the dissolved ozone concentration, pH, and the like with the instrument 20 provided in the pipe. Based on the measured dissolved ozone concentration, pH, etc., the amount of ozone-containing gas supplied to ultrapure water and the amount of chemical solution injected can be adjusted to manage the quality of ozone-dissolved water. In the apparatus according to the present invention, it is preferable that the wetted part and the wetted part of the ozone dissolving apparatus and the subsequent stage are all made of an ozone resistant material. Examples of the ozone-resistant material include fluororesin, quartz, and metal whose surface is passivated.
FIG. 3 is a process flow diagram of another aspect of (A) ultrapure water supply piping of the apparatus of the present invention. In this embodiment, the ultrapure water storage tank 21 is provided, and the ultrapure water supply pipe 12 is branched to provide the ultrapure water return pipe 22. By providing ultrapure water return piping and returning ultrapure water to the ultrapure water storage tank, the ultrapure water feed pump 11 can always be operated under constant conditions regardless of the amount of ultrapure water used. Even if the amount of ultrapure water used varies, the pressure of the ultrapure water supplied can be kept constant.
[0009]
FIG. 4 is a process flow diagram of another aspect of the (B) catalytic reaction section of the apparatus of the present invention. In this embodiment, the catalyst-packed tower 13 is packed with a palladium-supported resin 23, a cation exchange resin 24, and an anion exchange resin 25 in this order in a laminated state. FIG. 5 is a process flow diagram of another aspect of the (B) catalytic reaction section of the apparatus of the present invention. In this embodiment, the catalyst packed tower includes a palladium-supported resin tower 26, a mixed bed tower 27 of a cation exchange resin and an anion exchange resin, and both are connected in series in this order.
FIG. 6 is a process flow diagram of another aspect of the (D) ozone dissolving apparatus of the apparatus of the present invention. In this embodiment, the ultrapure water and the ozone-containing gas are in direct contact with each other at the ejector 28, and the ozone-containing gas is dispersed in the ultrapure water in the in-line mixer 29 and is dissolved in the ultrapure water. As the ozone stays at 30 and the dissolution of ozone proceeds, the finely dispersed bubbles recombine to form large bubbles, and the gas-liquid separator 17 separates the surplus gas to obtain ozone-dissolved water that does not contain bubbles. FIG. 7 is a process flow diagram of another aspect of the (D) ozone dissolving apparatus of the apparatus of the present invention. In this embodiment, a gas permeable membrane module 32 provided with a gas permeable membrane 31 made of fluorine resin having ozone resistance is used, and the ozone-containing gas is dissolved in ultrapure water through the gas permeable membrane.
By using the ozone-dissolved water production apparatus of the present invention, trace substances that promote the decomposition of ozone contained in ultrapure water can be removed and generated from pumps, catalyst-carrying resins, ion exchange resins, etc. Since ions and fine particles can also be removed, even if ozone-dissolved water is fed over long distances, the ozone concentration does not decrease much, the residual rate of dissolved ozone is high, and high-quality ozone-dissolved water that does not contain ions or fine particles Can be obtained.
[0010]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Comparative Example 1
Conventionally, using a subsystem equipped with an ultraviolet irradiation device, a mixed bed type ion exchange resin tower and an ultrafiltration device, a TOC concentration of 2.0 μg / liter of primary pure water 10 m ³ / h was treated to produce a TOC concentration. 0.5 μg / liter of ultrapure water was obtained. The ultraviolet irradiation device [Nippon Photo Science Co., Ltd., AUV-4800TC] is equipped with 24 ultraviolet lamps and has a total power consumption of 4 kW. The mixed bed ion exchange resin tower is filled with 65 liters of strongly basic anion exchange resin [Dawex Co., Ltd., 550A] and 35 liters of strongly acidic cation exchange resin [Dowex Co., Ltd., 650C]. is there.
Of this ultrapure water, 1 m ³ / h was branched into ozone-dissolved water, and an ozone-containing gas 125 liter / h with an ozone concentration of 160 g / m ³ produced by a silent discharge method of oxygen gas, that is, 20 g / h as ozone. Ozone-dissolved water was produced by supplying via an ejector. The ozone-dissolved water was sampled from the ozone-dissolved water supply pipe at a position 50 m away from the ejector, and the ozone concentration was measured and found to be 5 mg / liter.
Example 1
The same operation as in Comparative Example 1 was performed, except that 5 liters of anion exchange resin carrying 1% by weight of palladium, that is, 5% of the ion exchange resin as the layer height, was loaded on the top of the mixed bed type ion exchange resin tower. .
The TOC concentration of the obtained ultrapure water was 0.5 μg / liter, which was the same as Comparative Example 1. The ozone concentration of the ozone-dissolved water sampled at a position 50 m away from the ejector was 9 mg / liter.
Example 2
A palladium-supported resin tower and an ultrafiltration device filled with 1 liter of anion exchange resin 1% by weight of palladium as in Example 1 on the downstream side of the branch point where ultrapure water was branched for ozone-dissolved water at 1 m ³ / h. The same operation as Comparative Example 1 was performed except that it was installed and ultrapure water was passed.
The ozone concentration of ozone-dissolved water sampled at a position 50 m away from the ejector was 10 mg / liter.
From the results of Comparative Example 1 and Examples 1-2, a catalyst reaction part filled with palladium-supported anion exchange resin was provided in the previous stage of the ozone dissolution apparatus, ultrapure water was brought into contact with palladium-supported anion exchange resin, and the catalyst reaction part was By filtering the ultrapure water that has passed through, using a filtration device, high-quality ozone-dissolved water is obtained, and even when this ozone-dissolved water is fed over a long distance, decomposition of ozone in the ozone-dissolved water is suppressed, It can be seen that the survival rate is high.
[0011]
【The invention's effect】
By using the ozone-dissolved water production apparatus of the present invention, trace substances that promote the decomposition of ozone contained in ultrapure water are removed, and ions and fine particles generated from pumps, catalyst-carrying resins, ion-exchange resins, etc. Since it can be removed, even if ozone-dissolved water is fed over a long distance, there is little decrease in ozone concentration, high residual rate of dissolved ozone, and high-quality ozone-dissolved water that does not contain ions or fine particles can be obtained. it can. In addition, the amount of ozone necessary for the production of ozone-dissolved water can be reduced.
[Brief description of the drawings]
FIG. 1 is a process flow diagram of an ozone-dissolved water supply device that supplies ozone-dissolved water in a gas-liquid mixed state with an ozone-containing gas.
FIG. 2 is a process flow diagram of one embodiment of the apparatus of the present invention.
FIG. 3 is a process flow diagram of another aspect of (A) ultrapure water supply piping of the apparatus of the present invention.
FIG. 4 is a process flow diagram of another embodiment of the (B) catalytic reaction section of the apparatus of the present invention.
FIG. 5 is a process flow diagram of another embodiment of the (B) catalytic reaction section of the apparatus of the present invention.
FIG. 6 is a process flow diagram of another embodiment of (D) an ozone dissolving apparatus of the apparatus of the present invention.
FIG. 7 is a process flow diagram of another aspect of (D) the ozone dissolving apparatus of the apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Oxygen gas container 2 Nitrogen gas container 3 Ozone generator 4 Ozone dissolution apparatus 5 Gas-liquid mixed fluid supply piping 6 Branch pipe 7 Use point 8 Gas-liquid separator 9 Ozone decomposition apparatus 10 Ozone decomposition apparatus 11 Ultrapure water supply pump DESCRIPTION OF SYMBOLS 12 Ultrapure water supply piping 13 Catalytic reaction part 14 Filtration apparatus 15 Ozone dissolution apparatus 16 Ozone generator 17 Gas-liquid separator 18 Chemical solution tank 19 Chemical injection pump 20 Instrument 21 Ultrapure water storage tank 22 Ultrapure water return piping 23 Palladium carrying resin 24 Cation Exchange Resin 25 Anion Exchange Resin 26 Palladium-Supported Resin Tower 27 Mixed Bed Tower 28 Ejector 29 In-Line Mixer 30 Dissolution Promotion / Bubble Coalescence Promotion Unit 31 Gas Permeation Membrane 32 Gas Permeation Membrane Module

Claims (4)

(A) ultrapure water supply pipe ultrapure water is supplied from (B) said ultrapure connected to the water supply pipe, OH radicals present in the ultrapure water, palladium resins for removal of H radicals A catalyst packed tower in which a palladium-supported resin and an ion-exchange resin coexist, which are catalytic reaction units for contacting the redox catalyst and ultrapure water , (C) a filtration device for filtering ultrapure water that has passed through the catalyst packed tower, D) A device for producing ozone-dissolved water, comprising an ozone dissolving device for dissolving ozone in ultrapure water discharged from a filtration device.   The apparatus for producing ozone-dissolved water according to claim 1, wherein the catalyst packed tower is filled with a palladium-supported resin and a cation exchange resin or a palladium-supported resin, a cation exchange resin and an anion exchange resin in a mixed state or a laminated state.   The apparatus for producing ozone-dissolved water according to claim 1, wherein the catalyst-packed tower comprises a palladium-supported resin tower and a cation exchange resin tower connected in series in this order.   The apparatus for producing ozone-dissolved water according to claim 1, wherein the catalyst-packed tower comprises a palladium-supported resin tower, a cation exchange resin tower, and an anion exchange resin tower connected in series in this order.

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