JP2007325981A - Circulation-type apparatus for preparing ozone water and method for operating the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circulation-type apparatus for preparing ozone water capable of always maintaining an ozone concentration in the ozone water in a circulation path in the apparatus at a predetermined value and supplying the ozone water having a predetermined ozone concentration to a cleaning tank. <P>SOLUTION: The circulation type apparatus for preparing ozone water stably supplies ozone water having a predetermined ozone concentration prepared by steps of measuring the ozone concentration in the ozone water in an ozone dissolving tank 3, controlling the ozone gas supply to the ozone dissolving tank 3 by controlling electrolysis current to an electrolysis-type ozone gas generator 1 and/or switching the ozone flow by valve B from the measured value, controlling the liquid level in a circulation tank 2 by virtue of a level gauge LS attached to the circulation tank 2, and maintaining the ozone concentration in the ozone water in the circulation path at a predetermined value by repeating replenishment and suspension thereof of ultrapure water to the circulation tank 2. A method for operating the same is also disclosed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention significantly reduces the amount of ultrapure water used, enables water saving, makes the rise time of the ozone water concentration zero, and circulates in the circulating ozone water supply device. The present invention relates to a circulation type ozone water production apparatus for maintaining ozone water concentration in a path at a set concentration at all times and constantly supplying ozone water having a set ozone water concentration to a cleaning tank, and a method for operating the device.

In recent years, people's interest in the environment has increased, and these reductions have become a daily issue even in semiconductor manufacturing plants that consume a large amount of resources such as energy, water, and chemicals. In particular, ultrapure water used for cleaning, etc. in semiconductor factories is strictly controlled by multiple processes such as activated carbon treatment, UV oxidation, RO membrane treatment, UF membrane, ion exchange, electrodialysis, and degassing. In this process, a large amount of energy is consumed, and many chemicals and equipment are consumed in the process. For this reason, the reduction in the amount of ultrapure water used is directly linked to energy saving and resource saving in semiconductor manufacturing plants, and of course, it has a major impact on the manufacturing cost of semiconductor devices manufactured in the factory, and in turn on price competitiveness. give.
Ozone water used in semiconductor manufacturing plants is mainly used for surface cleaning and surface oxidation of silicon wafers on which bare wafers and semiconductor circuits are formed. Ozone has the strong oxidizing power after fluorine and becomes harmless oxygen after the reaction and after the lapse of time. Therefore, ozone water in which ozone gas in the order of ppm is dissolved in ultrapure water is the conventional concentrated sulfuric acid. Compared with cleaning methods that frequently use chemical solutions such as the above, it is advantageous in terms of cleanliness, oxidation ability, and simplification of post-treatment, and is widely spread.

  As a method for producing ozone water used for semiconductor cleaning, a gas-liquid contact method through a porous PTFE membrane is employed. In this method, an ozone dissolution tank is configured so that ozone gas is circulated on one side of the porous PTFE membrane housed in the housing and ultrapure water is circulated on the other side. It is a method of dissolving in ultrapure water. The advantages of this ozone water production method are that, unlike the bubbling method using bubbles, the concentration of ozone water produced is easy to stabilize over time because the gas-liquid contact area is constant, and ozone gas is made of porous PTFE. Fine ozone in the ozone gas can be removed to make ultra pure water contact after passing through, and clean ozone water can be produced, the porous PTFE membrane itself has sufficient ozone resistance, and the generation of impurities due to deterioration of the membrane itself Advantages in use in semiconductor manufacturing, such as the absence of contamination in ultrapure water.

  However, according to the above method, there is a problem that ozone water having a constant concentration cannot be obtained unless the ozone gas concentration in the housing is constant. This is a problem that depends on the gas side volume of the ozone dissolution tank and the flow rate of ozone gas supplied to the ozone dissolution tank. The concentration of the ozone water generated while the concentration is rising to the set ozone water concentration reaches the set value. It cannot be used for cleaning because it is not, and it will continue to be discarded in the drainage line, so that expensive ultrapure water is wasted. Also, when ozone water is used intermittently in the semiconductor cleaning process, it is necessary to continue to produce ozone water in order to keep the ozone water concentration constant even when ozone water is not used at the point of use. There is a problem that ozone water must be thrown away.

Further, ozone gas dissolved in water is OH in water ^- eventually the oxygen through various radicals react with ions. This process is called autolysis of dissolved ozone in water.
In recent years, in order to reduce the total amount of organic matter (TOC) in ultrapure water, the ultrapure water is irradiated with highly oxidizing 185 nm ultraviolet rays to oxidize trace organics in ultrapure water to carbonate ions, and ion exchange resin. In general, a processing method of capturing / removing with the above method is used. By this processing method, the TOC in the ultrapure water becomes a value less than 1 ppb. At this time, a trace amount of hydrogen peroxide is generated by the photoreaction of dissolved oxygen and water. Both the decrease in TOC and the incorporation of hydrogen peroxide in ultrapure water increase the self-decomposition rate of ozone, resulting in a decrease in the concentration of generated ozone water in the ozone water production system and a significant concentration of ozone water in pipes and cleaning tanks. Appears as a phenomenon of decline. This phenomenon makes it difficult to manage the concentration in the cleaning tank, and the concentration of ozone water that can be used is low. The semiconductor cleaning process using ozone water itself is unstable and less effective. turn into.

  That is, when ozone water is continuously supplied to a cleaning tank such as a semiconductor, it is possible to stably supply ozone water having a preset concentration by continuously supplying a certain amount of ultrapure water and ozone gas. However, depending on the cleaning method for semiconductors, etc., it may be necessary to supply ozone water intermittently. In this case, in the conventional method, the ozone water supply stop time is provided or the ozone water supply is started from the point of use. It was necessary to switch to the drain line and continue discharging. However, in this way, when switching the line for stopping the device or draining, fluctuations in the flow rate of ozone water cause fluctuations in concentration, and it is difficult to make the rise time until it stabilizes to the desired concentration, There was a loss of cleaning time.

  In order to eliminate the above drawbacks, gas dissolved water that has not been used in washing machines in recent years is returned to the water tank, the concentration of the specific gas dissolved in the gas dissolved water is maintained at a certain value or more, and the gas dissolved A circulation type ozone water production apparatus that can keep the concentration of a specific gas in an upper space of a water tank storing water low has been proposed.

  As shown in FIG. 3, this conventional apparatus includes a dissolving device A for producing a specific gas-dissolved water, a water tank B for storing a specific gas-dissolved water, a connecting pipe C for connecting the dissolving device A and the water tank B, and a water tank B. Gas dissolved water having a pump D for sending stored water to the washing machine, a circulation pipe E returning from the water tank B to the pump D and the washing machine through the branch point to the water tank B, and a gas pipe F for supplying gas to the upper space of the water tank B It is a supply apparatus, Comprising: The lower end of the connection piping C and the lower end of the circulation piping E are submerged under the water surface in the water tank B, It is characterized by the above-mentioned. In this conventional apparatus, when supplying a gas-dissolved water (corresponding to ozone water according to the present invention) obtained by dissolving a specific gas in ultrapure water and a specific gas to a water tank B (corresponding to an ozone dissolving tank according to the present invention) The concentration of the specific gas in the upper space of the water tank B is kept low by adjusting the positions of the gas pipe, dissolved water, and circulating water pipe in the water tank. However, in this conventional apparatus, the concentration of the specific gas in the upper space of the water tank B is kept low by adjusting the position of the supply gas pipe, dissolved water, and circulating water pipe in the water tank B. It was extremely difficult to control the concentration of dissolved gas water. (Patent Document 1).

In addition, this conventional device is a device mainly intended for water in which hydrogen is dissolved instead of ozone as a specific gas, and the change in hydrogen concentration in the circulation device is caused by an upper space gas phase (inactive in the water tank B). Gas or air), and there is no change in concentration in piping that is not in contact with the gas phase. On the other hand, when ozone water is targeted, in addition to this, there is self-decomposition, and the dissolved ozone concentration is lowered only in time (even during transfer) in the piping. No countermeasure has been taken, and when used for ozone water, it is difficult to maintain the concentration, and ozone water having a stable concentration cannot be obtained. That is, in this conventional apparatus, since the following mechanism is not provided, ozone water having a stable concentration cannot be obtained.
・ Concentration measurement mechanism in the circulation line ・ Gas supply mechanism to the dissolution tank controlled by the measured value of the concentration measurement mechanism ・ Liquid level management mechanism in the circulation tank ・ Pure water supply to the circulation tank controlled by the liquid level management mechanism mechanism

That is, in the above conventional apparatus, when this is applied to ozone water,
Ozone gas / ultra pure water → Dissolved in dissolution tank → Ozone water, so even if ozone gas / ultra pure water controlled to a certain amount is supplied, when starting up this conventional device, it is The filled ozone gas space in the dissolution tank must be replaced with a constant concentration of ozone gas that is balanced by the supply of ozone gas and the generation and discharge of ozone water. Since ozone is dissolved in ozone water and discharged from the dissolution tank, the replacement speed becomes slow, and the concentration of ozone water generated and discharged is not easily constant until the replacement is completed. It took about 1 hour to keep it constant. Even if the dissolution tank is filled with a constant concentration of ozone gas at the same concentration as the ozone gas supplied from the ozone gas generator in advance and the apparatus is started to start only pure water supply, the concentration of ozone gas in the dissolution tank However, it took several tens of minutes to be balanced with the ozone water generation conditions. If the ozone water supply to the washing machine is intermittent, the latter will be in operation, but in order not to lengthen the processing waiting time even slightly, the ozone water concentration and flow rate are kept constant by constantly producing ozone water. However, even when not used at the point of use, a large amount of useless ozone water was continuously produced, and a large amount of ultrapure water used as raw ozone water was required.

Japanese Patent Laying-Open No. 2005-262031 (Claim 1, FIG. 3)

  The object of the present invention is to eliminate the drawbacks of the above-described conventional methods, greatly reduce the amount of ultrapure water to be used, enable water saving, and make the rise time of the ozone water concentration zero, In addition, there is provided a circulating ozone water production apparatus capable of constantly maintaining the ozone water concentration in the circulation path at a set concentration and stably supplying the ozone water having the set ozone water concentration to the cleaning tank, and an operation method of the device. It is to provide.

  In order to achieve the above object, the present invention includes an electrolytic ozone gas generator 1 for electrolyzing ultrapure water to generate ozone gas, a circulation tank 2 for circulating ozone water, and an electrolytic ozone gas generator 1. An ozone dissolution tank 3 for dissolving a part of the generated ozone gas to generate ozone water, an ozone water outlet 5 for supplying a part of the ozone water generated by the ozone dissolution tank 3 to a use point, A connection pipe 6 for supplying pure water to the circulation tank 2 via the valve A and a connection pipe 7 for supplying a part of the ozone gas generated from the electrolytic ozone gas generator 1 to the ozone dissolution tank 3 via the valve B And the connection pipe 8 for supplying the ultrapure water in the circulation tank 2 and the circulated ozone water to the ozone dissolution tank 3 through the circulation pump P and the valve C, and the ozone dissolution tank 3. A connecting pipe 10 for supplying a part of the ozone water to the ozone water outlet 5 via the valve D, a connecting pipe 11 for circulating from the front of the ozone water outlet 5 to the circulation tank 2, and circulating ozone An ozone water concentration measuring device 13 connected to the ozone dissolution tank 3 for adjusting water to a predetermined concentration and a liquid level gauge LS provided in the circulation tank 2, one of ozone water generated by the ozone dissolution tank 3. The ozone water is supplied to the use point from the ozone water outlet 5, and the remaining ozone water generated by the ozone dissolution tank 3 is circulated using the connection pipes 10, 11 and 8, and the ozone water produced in the ozone dissolution tank 3 The concentration of water is measured, and based on the measured value, the electrolytic current control to the electrolytic ozone gas generator 1 and / or the switching by the valve B are performed, and the ozone gas supply to the ozone dissolution tank 3 is performed. In addition, the liquid level gauge LS provided in the circulation tank 2 manages the liquid level in the circulation tank 2 and repeats the replenishment and stoppage of ultrapure water so that the concentration of ozone water in the circulation path is kept constant. It is in a circulating ozone water production apparatus that keeps and supplies ozone water with a set ozone water concentration stably.

  A second problem-solving means is that, in the circulating ozone water producing apparatus, a fluorocarbon spiral pump having a magnetic levitation type non-contact structure is used as the circulating pump P.

  Furthermore, the third problem solving means is that, in the circulating ozone water producing apparatus, a pipe for branching into ozone water outlet 5 into one or more outlets for supplying ozone water to a use point is connected.

  Further, the fourth problem solving means is that a total amount dissolved ozone concentration meter is used as the ozone water concentration measuring device 13 in the circulating ozone water producing apparatus.

  Furthermore, the fifth problem solving means is that in the circulating ozone water production apparatus, the filter F using a porous PTFE membrane having ozone resistance is connected to the connection pipe 10 between the ozone dissolution tank 3 downstream and the ozone water outlet 5. It was installed and removed the particles in the circulating ozone water to maintain the cleanliness of the circulating ozone water.

Furthermore, the sixth problem-solving means includes a step of generating ozone gas using the electrolytic ozone gas generator 1, and
Supplying a part of the ozone gas generated in the electrolytic ozone gas generator 1 to the ozone dissolution tank 3 via the connection pipe 7 and the valve B;
Supplying ultrapure water from the circulation tank 2 to the ozone dissolution tank 3 via the connection pipe 8, the pump P and the valve B;
Generating ozone water in the ozone dissolution tank 3,
Supplying a part of the ozone water generated in the ozone dissolution tank 3 to the ozone water outlet 5 using the connecting pipe 10 and the valve D;
Circulating a part of the ozone water from the front of the ozone water outlet 5 to the circulation tank 2 using the valve D and the connecting pipe 11;
Supplying ozone water in the circulation tank 2 to the ozone dissolution tank 3 for circulation;
The concentration of ozone water produced in the ozone dissolution tank 3 is measured by the ozone water concentration meter 13, and based on the measured value, the electrolytic current control to the electrolytic ozone gas generator 1 and / or the switching by the valve B is performed, and the ozone Controlling the ozone gas supply to the dissolution tank 3,
The liquid level gauge LS provided in the circulation tank 2 manages the liquid level in the circulation tank 2 and repeats the replenishment and stoppage of ultrapure water. The concentration of ozone water in the circulation path is kept constant, The present invention resides in a method for operating a circulating ozone water production apparatus characterized by stably supplying ozone water having a set ozone water concentration.

  Furthermore, a seventh problem solving means is to use ultrapure water in which carbon dioxide is dissolved as the ultrapure water supplied to the circulation tank 2 in the operation method of the circulating ozone water production apparatus.

  Further, the eighth problem-solving means is an operation method of the above circulating ozone water production apparatus, in which electrolysis is performed while supplying carbon dioxide to the anode chamber of the electrolytic ozone gas generator 1 that electrolyzes ultrapure water to generate ozone gas. Is to do.

  According to the present invention, the amount of ultrapure water used can be greatly reduced, water can be saved, the rise time of the ozone water concentration can be zero, and the concentration of ozone water in the circulation path can be reduced. It is possible to provide a circulating ozone water production apparatus and its operating method capable of always maintaining a set concentration and stably supplying ozone water having a set ozone water concentration to a cleaning tank.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
FIG. 1 is an overall view of a circulation type ozone water production apparatus according to the present invention, FIG. 2 is a detailed view of the circulation type ozone water production apparatus according to the present invention, and 1 is an electrolysis of ultrapure water. In the electrolytic ozone gas generator that generates ozone gas, a part of ultrapure water as a raw material is supplied via a valve A to the anode chamber 1b of the ozone gas generator 1a through a connection pipe. The ozone gas generated in the anode chamber 1b is supplied to the ozone dissolution tank 3 through the circulation tower 1d. The hydrogen gas generated in the cathode chamber 1c is released out of the system. Reference numeral 2 denotes a circulation tank for circulating ozone water generated by the ozone dissolution tank 3, and the remaining portion of the ultrapure water as a raw material is supplied to the circulation tank 2 from the connection pipe 6 through the valve A. . 4 is an ozone drain tank for draining the remainder of the ozone gas generated from the electrolytic ozone gas generator 1, and 5 is ozone water for supplying a part of the ozone water generated by the ozone dissolution tank 3 to a use point. The outlet 7 is a connecting pipe for supplying a part of the ozone gas generated from the electrolytic ozone gas generator 1 to the ozone dissolution tank 3 via the three-way valve B, and 8 is the ultrapure water in the circulation tank 2 and the circulating pipe 2 A connection pipe for supplying ozone water to the ozone dissolution tank 3 through the circulation pump P and the valve C, 9 is a connection pipe for supplying the remaining ozone gas generated from the electrolytic ozone gas generator 1 to the ozone drain tank 4 10 is a connection pipe for supplying a part of the ozone water generated by the ozone dissolution tank 3 to the ozone water outlet 5 through the valve D; A connection pipe 12 for circulating from the front of the ozone water outlet 5 to the circulation tank 2, 12 is a connection pipe 12 for supplying the remaining ozone water generated by the ozone dissolution tank 3 to the ozone drain tank 4. Yes, a large part of the ozone water generated by the ozone dissolution tank 3 is circulated and used using the connecting pipes 10, 11 and 8, and a part of the ozone water is supplied to the use point from the ozone water outlet 5, Ozone gas and ozone water are discharged from the drain tank 4 using the connecting pipes 9 and 12, and the ozone water concentration in the circulation path is kept constant, and the ozone water having the set ozone water concentration is stably supplied. . 13 is an ozone water concentration measuring device connected to the ozone dissolution tank 3 to adjust the circulating ozone water to a predetermined concentration, and measures the concentration of ozone water in the ozone dissolution tank 3 and based on the measured value. The electrolytic current control to the electrolytic ozone gas generator 1 and / or the switching by the valve B are performed, and the ozone gas supply to the ozone dissolution tank 3 is controlled. Further, LS is a liquid level gauge provided in the circulation tank 2, and the liquid level position where the capacitance type liquid level sensor is connected to the side surface of the circulation tank 2 or the upper and lower holes of the circulation tank 3 is the circulation tank 3. It is attached to a pipe that is the same as the above. There are four liquid level gauges LS from the top in the height direction, HH, H, L, and LL. HH and LL are for emergency stop, and liquid level management is performed by H and L. When ozone water is used at the point of use, the liquid level in the circulation tank 2 decreases, but when the liquid level drops to the L level sensor position, the valve A is opened to replenish the circulation tank 2 with pure water. When the liquid level rises due to the supply of pure water and the liquid level rises to the H level sensor position, the valve A is closed to stop the pure water supply. F is an ozone water filter, which is provided between the valve E and the valve H of the connection pipe 10 in the water discharge line of the ozone dissolution tank 3 to remove particles in the circulating ozone water, and only the concentration of the circulating ozone water Rather, it maintains the cleanliness of circulating ozone water.

The ozone water flow rate is monitored by the flow meter G, but the flow rate setting was controlled by adjusting the number of rotations of the circulation pump P. The ozone gas was produced using the electrolytic ozone gas generator 1. The ozone gas concentration is 200 g / Nm ³ , and the ozone gas supply amount is 24 g / hr. A part of the ozone gas passes through the connecting pipe 7 and is switched by the three-way valve B, supplied to the ozone dissolution tank 3, and used for ozone water production. The remainder of the ozone gas passes through the connection pipe 9 without passing through the ozone dissolution tank 3, passes through the ozone drain tank 4, and is treated with the ozone catalyst. When the measured value from the ozone water concentration meter 13 is lower than the set ozone water concentration value, the three-way valve B opens to the NC side, supplies ozone gas to the ozone dissolution tank 3, and is higher than the set ozone water concentration value. Opens to the NO side and allows ozone gas to flow into the ozone drain tank 4. Ultrapure water, which is raw water for ozone water production, is stored in the circulation tank 2 through the valve A and the connection pipe 8, and then contacts ozone gas in the ozone dissolution tank 3 by the circulation pump P to become ozone water.

  That is, the circulation type ozone water production apparatus according to the present invention is pure water → circulation tank 2 → dissolving ozone gas in the ozone dissolution tank 3 → ozone water → circulation tank 2 (return). 2 and the ozone water concentration measured value 13 are controlled by the liquid level gauge LS. Therefore, in the circulation type ozone water supply apparatus in the present invention, since the ozone water is circulated in the system until the ozone water concentration reaches the specified value, it is not necessary to continue generation and discharge as in the conventional apparatus, Water saving and zero waste water. The zero start-up time here means that the time for discharging ozone water that has already reached the specified concentration in the circulation system is zero. For example, ozone water is intermittently supplied to the washing machine. In this case, it means that it is not necessary to wait for the ozone water concentration to rise as in the conventional apparatus.

  Next, the present invention will be specifically described with reference to examples and comparative examples. However, the present invention is not limited to these examples.

<Example 1>
The present invention was implemented using the apparatus shown in FIG.
The following equipment was used for main equipment. Moreover, all the parts in contact with ozone water and ozone gas in the system were made of fluororesin.
(1) Electrolytic ozone gas generator 1: manufactured by Chlorine Engineers Co., Ltd., electrolytic ozone gas generator, trade name, Purezone (registered trademark), ozone gas generation amount 24 g / hour, ozone gas concentration 200 g / Nm ³
(2) Circulation tank 2: PTFE lining SUS tank Volume 30 L / min.
(3) Circulation pump P: magnetic levitation canned centrifugal pump (Iwakiretro pump LEV750)
(4) Ozone water concentration meter 13: UV-type ozone water concentration meter (EL-550, manufactured by Sugawara Jitsugyo), UV-type full-volume ozone water concentration meter (Aplix OD-UND-200-PC-R)
(5) Ozone water filter F: PTFE filter (manufactured by Kurabo Industries, KF2LS10005M / E)
(6) Flow meter G: Karman vortex flow meter (manufactured by Sagamiya Seisakusho, SLK)
(7) Ozone dissolution tank 3: Porous PTFE membrane type ozone dissolution tank (manufactured by Japan Gore-Tex)
(8) In-liquid particle counter (Rion KS-40A): installed at the tip of the valve H.
When the device is started up and when the flow rate is changed, if the ozone gas supply amount is constant, it takes 10 minutes or more for the ozone water concentration to stabilize when the ozone water concentration at the time of device startup and the ultrapure water flow rate are changed thereafter. However, after that, the valve D was closed and a circulation system for returning the ozone water to the circulation tank 2 was constructed, the set ozone water concentration was set to 15 ppm, and the three-way valve B was automatically switched. The amount of circulating ozone water was set to 15 L / min.
Test results: The amount of ozone water was 14.4-15.7 L / min, the concentration of ozone water was 14.5 to 15.3 ppm, and both the amount of ozone water and the concentration of ozone water were stable. In addition, there was no wasted water, saving water for ultrapure water. Furthermore, it takes no time to discharge the ozone water that has already reached the specified concentration in the circulation system, and there is no need to wait for the ozone water concentration to be raised unlike the conventional apparatus.

<Comparative Example 1>
In the state of Example 1, the set ozone water concentration was not particularly provided, and the three-way valve B was always opened on the NC side (ozone dissolution tank 3 side), and the circulating ozone water amount was set to 15 L / min.
Test result: The ozone concentration increased over time to over 50 mg / L, but then bubbles were significantly mixed into the ozone water, and measurement with an ultraviolet ozone water concentration meter became impossible. When a large amount of air bubbles is mixed into the semiconductor at the point of use, the water flow rate is not stable, and when the semiconductor is immersed in the bath for cleaning, bubbles adhere to the surface of the object to be cleaned and are uniform. Could not wash. Even in the ozone water production apparatus, a large amount of bubbles mixed in had a drawback that the circulation pump operation was not stable, and if bubbles adhered to the surface of the porous PTFE membrane, the gas-liquid contact area was not stable and the dissolution performance was not stable. .

<Example 2>
In the state of Example 1, carbon dioxide gas was supplied to the electrolytic cell anode chamber at 10 ml / min, the set ozone water concentration was set to 15 ppm, and the three-way valve B was automatically switched. The amount of circulating ozone water was set to 15 L / min. Particle measurements were also performed.
Test results: The ozone water amount was 13.4 to 14.4 L / min and the ozone water concentration was 14.6 to 15.2 ppm. Particles were 0.1 μmφ or more and 50 particles / 10 ml or less. The ozone water concentration stability was practically used, and the amount of particles was at a level that could be used for semiconductor cleaning. The decrease in ozone water concentration over time was smaller than that in Example 1, and the concentration fluctuation range was small. In addition, there was no wasted water, saving water for ultrapure water. Furthermore, it takes no time to discharge the ozone water that has already reached the specified concentration in the circulation system, and there is no need to wait for the ozone water concentration to be raised unlike the conventional apparatus.

<Example 3>
In the state of Example 1, carbon dioxide was added to ultrapure water, the specific resistance of ultrapure water was 1 MΩ · cm, and raw ozone water was obtained. The set ozone water concentration was 15 ppm, and automatic switching of the three-way valve B was performed. The amount of circulating ozone water was set to 15 L / min. Particle measurements were also performed.
Test results: The ozone water amount was 14.4-15.4 L / min, and the ozone water concentration was 14.6-15.2 ppm. Particles were 0.1 μmφ or more and 50 particles / 10 ml or less. The ozone water concentration stability was practically used, and the amount of particles was at a level that could be used for semiconductor cleaning. In addition, there was no wasted water, saving water for ultrapure water. Furthermore, it takes no time to discharge the ozone water that has already reached the specified concentration in the circulation system, and there is no need to wait for the ozone water concentration to be raised unlike the conventional apparatus.

  In addition, when the ozone water filter F was removed in the state of Example 1 and the particles were measured, the number of particles was 0.1 μmφ or more and 100000 pieces / 10 ml or more.

<Example 4>
In the state of Example 1, water was drained at 5 L / min for 10 minutes from the valve D in front of the ozone water outlet 5, and a flow rate of 15 L / min was passed through the flow meter G. Further, carbon dioxide gas was supplied to the anode chamber of the electrolytic ozone gas generator 1 at 10 ml / min. The set ozone water concentration was 15 ppm, and automatic switching of the three-way valve B was performed. The amount of circulating ozone water was set to 15 L / min. Particle measurement was performed. While draining 5 L / min from valve | bulb D, the same amount of water supply was always implemented simultaneously.
Test results: The ozone water amount changed from 11.9 to 14.0 L / min and the ozone water concentration changed from 13.8 to 15.6 ppm. Particles were 0.1 μmφ or more and 50 particles / 10 ml or less. Ozone water concentration stability is at a level that can be used practically. The amount of particles was also at a level that could be used for semiconductor cleaning. In addition, there was no wasted water, saving water for ultrapure water. Furthermore, it takes no time to discharge the ozone water that has already reached the specified concentration in the circulation system, and there is no need to wait for the ozone water concentration to be raised unlike the conventional apparatus.

  According to the circulation type ozone water production apparatus and the operation method of the apparatus according to the present invention, the amount of ultrapure water to be used is greatly reduced, water can be saved, and the rise time of the ozone water concentration is made zero. In addition, the ozone water concentration in the circulation path can always be kept at the set concentration, and the ozone water having the set ozone water concentration can be stably supplied to the cleaning tank.

1 is an overall view of a circulating ozone water production apparatus according to the present invention. Detailed drawing of the circulation type ozone water manufacturing apparatus by this invention. The figure which shows the circulation type ozone water manufacturing apparatus of a conventional apparatus.

Explanation of symbols

1: Electrolytic ozone gas generator 1a: ozone gas generator 1b: anode chamber 1c: cathode chamber 1d: circulation tower 2: circulation tank 3: ozone dissolution tank 4: ozone drain tank 5: ozone water outlet 6: connection pipe 7: connection Pipe 8: Connection pipe 9: Connection pipe 10: Connection pipe 11: Connection pipe 12: Connection pipe 13: Ozone water concentration meter 14: Connection pipe A: Valve B: Valve C: Valve D: Valve E: Valve P: Pump F : Ozone water filter G: Flow meter H: Valve LS: Liquid level gauge

Claims (8)

  An electrolytic ozone gas generator 1 that electrolyzes ultrapure water to generate ozone gas, a circulation tank 2 for circulating ozone water, and a part of ozone gas generated from the electrolytic ozone gas generator 1 are dissolved to generate ozone water. An ozone dissolution tank 3 for generating, an ozone water outlet 5 for supplying a part of the ozone water generated by the ozone dissolution tank 3 to the use point, and ultrapure water to the circulation tank 2 via the valve A Connection piping 6 for supplying, connection piping 7 for supplying a part of ozone gas generated from the electrolytic ozone gas generator 1 to the ozone dissolution tank 3 through the valve B, ultrapure water and circulation in the circulation tank 2 A connecting pipe 8 for supplying the ozone water to the ozone dissolution tank 3 through the circulation pump P and the valve C, and a part of the ozone water generated by the ozone dissolution tank 3 through the valve D A connection pipe 10 for supplying to the ozone water outlet 5, a connection pipe 11 for circulating from the front of the ozone water outlet 5 to the circulation tank 2, and an ozone dissolution tank 3 for adjusting the circulating ozone water to a predetermined concentration. The ozone water concentration measuring device 13 connected to the liquid tank and a liquid level gauge LS provided in the circulation tank 2, supplying a part of the ozone water generated by the ozone dissolution tank 3 from the ozone water outlet 5 to the use point, While circulating the remaining ozone water generated by the ozone dissolution tank 3 using the connecting pipes 10, 11 and 8, the concentration of the ozone water produced in the ozone dissolution tank 3 is measured, and based on the measured value, The electrolytic current control to the electrolytic ozone gas generator 1 and / or the switching by the valve B are performed to control the supply of the ozone gas to the ozone dissolution tank 3 and the circulation tank 2 is provided. The liquid level gauge LS manages the liquid level in the circulation tank 2 and repeats the replenishment and stoppage of ultrapure water to keep the concentration of ozone water in the circulation path constant. A recirculating ozone water production apparatus characterized by stably supplying water.   2. The circulating ozone water production apparatus according to claim 1, wherein a fluorine resin spiral pump having a magnetic levitation type non-contact structure is used as the circulation pump P.   The circulating ozone water production apparatus according to claim 1, wherein the ozone water outlet 5 is connected to a pipe branched into a single port or a plurality of ports for supplying ozone water to a use point.   The circulating ozone water production apparatus according to claim 1, wherein a total quantity dissolved ozone concentration meter is used as the ozone water concentration measuring device 13.   A filter F using a porous PTFE membrane having ozone resistance is installed in a connection pipe 10 between the ozone dissolution tank 3 downstream and the ozone water outlet 5 to remove particles in the circulating ozone water and clean the circulating ozone water. The circulating ozone water production apparatus according to claim 1, which maintains the property. Generating ozone gas using the electrolytic ozone gas generator 1;
Supplying a part of the ozone gas generated in the electrolytic ozone gas generator 1 to the ozone dissolution tank 3 via the connection pipe 7 and the valve B;
Supplying ultrapure water from the circulation tank 2 to the ozone dissolution tank 3 via the connection pipe 8, the pump P and the valve B;
Generating ozone water in the ozone dissolution tank 3,
Supplying a part of the ozone water generated in the ozone dissolution tank 3 to the ozone water outlet 5 using the connecting pipe 10 and the valve D;
Circulating a part of the ozone water from the front of the ozone water outlet 5 to the circulation tank 2 using the valve D and the connecting pipe 11;
Supplying ozone water in the circulation tank 2 to the ozone dissolution tank 3 for circulation;
The concentration of ozone water produced in the ozone dissolution tank 3 is measured by the ozone water concentration meter 13, and based on the measured value, the electrolytic current control to the electrolytic ozone gas generator 1 and / or the switching by the valve B is performed, and the ozone Controlling the ozone gas supply to the dissolution tank 3,
The liquid level gauge LS provided in the circulation tank 2 manages the liquid level in the circulation tank 2 and repeats the replenishment and stoppage of ultrapure water. The concentration of ozone water in the circulation path is kept constant, A method for operating a circulating ozone water production apparatus, wherein ozone water having a set ozone water concentration is stably supplied.   The operation method of the circulating ozone water production apparatus according to claim 6, wherein ultrapure water in which carbon dioxide is dissolved is used as the ultrapure water supplied to the circulation tank 2. The operating method of the circulating ozone water manufacturing apparatus of Claim 6 which electrolyzes supplying carbon dioxide to the anode chamber of the electrolytic ozone gas generator 1 which electrolyzes ultrapure water and produces | generates ozone gas.

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