JP4097778B2 - Gas dissolved cleaning water supply piping - Google Patents

Description

【００１０】
第１表の結果から、分岐配管の流速Ｖ₂と主配管の流速Ｖ₁の比、Ｖ₂／Ｖ₁、が０.８５以上になると分岐配管中に気泡が移行するが、Ｖ₂／Ｖ₁を０.８５未満とすることにより、バッファタンクなどの気液分離装置を設置しなくても、主配管から気泡の巻き込みのないガス溶解洗浄水を取り出して、ユースポイントで使用し得ることが分かる。
【００１１】
【発明の効果】
本発明のガス溶解洗浄水供給配管によれば、オゾン含有ガス、酸素ガス、水素ガスなどの酸化性ガス又は還元性ガスと純水を、主配管内で混合しつつ通水するガス溶解洗浄水供給システムにおいて、分岐配管に気液分離装置を設けることなく、ユースポイントにおいて気液分離された気泡の巻き込みのないガス溶解洗浄水を得ることができる。
【図面の簡単な説明】
【図１】図１は、従来のオゾン溶解洗浄水供給システムの工程系統図である。
【図２】図２は、本発明の配管の一態様の説明図である。
【図３】図３は、オゾン定濃度保持機構の説明図である。
【図４】図４は、実施例に用いた試験配管の概略図である。
【符号の説明】
１ 酸素ガス容器
２ 窒素ガス容器
３ オゾン発生器
４ オゾン溶解装置
５ 主配管
６ 分岐配管
７ ユースポイント
８ オゾン分解装置
９ 気液分離装置
１０ 水供給配管
１１ ガス溶解装置
１２ 主配管
１３ 分岐配管
１４ 流量調整弁
１５ オゾン溶解用エジェクター
１６ 主配管
１７ 分岐配管
１８ テフロン製コネクター
１９ 透明テフロンチューブ
２０ ニードル弁
２１ メスシリンダー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas-dissolved cleaning water supply pipe. More specifically, the present invention supplies cleaning water having a substantially constant gas concentration to a use point even when cleaning water in which an oxidizing gas or a reducing gas is dissolved is transferred over a long distance in a wet cleaning process of an electronic material. In addition, the present invention relates to a gas-dissolved cleaning water supply pipe that can prevent bubbles from being mixed into cleaning water taken out from a branch pipe at a use point.
[0002]
[Prior art]
Removing foreign substances from the surface of electronic materials such as silicon substrates for semiconductors, glass substrates for liquid crystals, and quartz substrates for photomasks is extremely important for ensuring product quality and yield. Cleaning is widely performed. To remove organic and metal contamination, it is effective to apply a cleaning solution with strong oxidizing power. Conventionally, a mixed solution of sulfuric acid and hydrogen peroxide (SPM cleaning solution), or 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. Reducing the cost of chemicals when using these cleaning methods, the cost of ultra-pure water for rinsing, the cost of waste liquid treatment, the air conditioning cost of exhausting chemical vapor and creating clean air, and the use of large amounts of water In recent years, the wet cleaning process has been reviewed in order to reduce the burden on the environment, such as mass disposal of drugs and emission of exhaust gas.
The inventors previously cleaned electronic materials in which gases such as ozone, oxygen gas, hydrogen gas, carbon dioxide gas, chlorine gas, nitrogen gas, and rare gas were dissolved in pure water according to the object to be cleaned and the purpose of cleaning. Developed gas-dissolved cleaning water. For example, cleaning water in which ozone is dissolved in pure water exhibits extremely high oxidizing power despite the low concentration of dissolved ozone of several mg / liter, and is effective for organic contamination and metal contamination attached to the surface of electronic materials. Can be removed. In addition, cleaning water in which oxygen gas or hydrogen gas is dissolved is effective in removing particulate contamination adhering to the surface of the electronic material. Many of these gas-dissolved cleaning waters have the advantage that they can be reused by converting or dissolving dissolved gases into high-purity water. However, the ozone-dissolved cleaning water is self-degraded with time and becomes oxygen gas, so that it is difficult to maintain and maintain the ozone concentration, and it has been difficult to supply it by long-distance piping.
On the other hand, the inventors of the present invention first supplied ozone-containing gas and pure water while mixing them in a supply pipe, thereby suppressing a decrease in ozone concentration and enabling long-distance water distribution. As a result, an ozone-dissolved cleaning water supply system shown in FIG. 1 was proposed. 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. , It is fed into pure water produced by using an ion exchange device, a membrane device, an ultraviolet oxidizer or the like using an ejector, a pump or the like. The mixed gas of ozone and oxygen gas is mixed with pure water to be in a gas-liquid mixed state, ozone is dissolved in water to generate ozone-dissolved cleaning water, and further flows in the main pipe 5 in the gas-liquid mixed state. . 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 cleaning water is taken out from the branch pipe 6 and is consumed at the use point 7 after being separated from the gas and liquid in a gas-liquid separator such as a buffer tank. Excess ozone-dissolved cleaning water that has not been taken out from the branch pipe is decomposed and removed by ozone decomposition apparatus 8 in the aqueous phase and in the gas phase, and then guided to gas-liquid separation apparatus 9 where it is separated into a gas phase and an aqueous phase. The gas phase is opened to the atmosphere as exhaust gas, and the water phase is recovered as waste water, and is recycled after necessary treatment.
If bubbles are mixed in the gas-dissolved cleaning water and used at the point of use, fine bubbles will adhere to the surface of the electronic material that is the object to be cleaned, and the electronic material will be contaminated by foreign substances that collect on the surface of the bubbles. The gas-dissolved cleaning water used at the point of use must be completely free of bubbles. In addition to ozone-dissolved cleaning water, oxygen gas-dissolved cleaning water, hydrogen gas cleaning water, etc. are also sent directly into the piping using an inline mixer etc. For example, it is necessary to perform gas-liquid separation at the point of use. However, since a device provided with a gas-liquid separation device such as a buffer tank for each use point is complicated and its management is complicated, a simple device that can easily perform gas-liquid separation of dissolved gas cleaning water Is now required.
[0003]
[Problems to be solved by the invention]
The present invention can supply cleaning water having a substantially constant gas concentration to the use point even if the cleaning water in which the oxidizing gas or the reducing gas is dissolved is transferred over a long distance in the wet cleaning process of the electronic material. In addition, the object of the present invention is to provide a gas-dissolved cleaning water supply pipe that can prevent bubbles from being mixed into the cleaning water taken out from the branch pipe at the use point.
[0004]
[Means for Solving the Problems]
As a result of intensive research to solve the above problems, the inventors of the present invention attached a branch pipe downward to the main pipe for transferring the gas-dissolved washing water in a gas-liquid mixed state to take out the washing water, and branch off. We found that it is possible to take out the washing water without bubbles by attaching a flow control valve to the pipe and reducing the flow rate of the washing water in the branch pipe, and the present invention was completed based on this knowledge. It came to do.
That is, the present invention
(1) in the supply pipe for supplying gas dissolved cleaning water to the use point, the wash water in the pure water to dissolve the ozone gas, the main pipe for transferring in the presence of ozone gas, a branch pipe of taking out the washing water from the main pipe The gas-dissolved cleaning water supply pipe, characterized in that the pipe is attached downward from the almost horizontal main pipe and the flow control valve is attached to the branch pipe, and ( 2 ) the gas-dissolved cleaning water supply pipe of (1) In the gas-dissolved cleaning water supply method used, the gas-dissolved cleaning water supply is characterized in that the flow rate of the cleaning water in the branch pipe is adjusted to be smaller than the flow rate of the cleaning in the main pipe by a flow rate adjusting valve attached to the branch pipe. Method,
Is to provide.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The gas-dissolved cleaning water supply pipe of the present invention is cleaned from the main pipe to the main pipe for transferring cleaning water in which oxidizing gas or reducing gas is dissolved in pure water in the presence of oxidizing gas or reducing gas. A branch pipe for taking out water is attached downward, and a flow rate adjusting valve is attached to the branch pipe. Drawing 2 is an explanatory view of one mode of piping of the present invention. Pure water or ultrapure water is supplied to the water supply pipe 10, and in the gas dissolving device 11, an oxidizing gas or a reducing gas is supplied and dissolved in pure water or ultrapure water to prepare cleaning water. The oxidizing gas or reducing gas supplied to the gas dissolving apparatus is preferably washed in advance as necessary to remove gas components other than the target oxidizing gas or reducing gas and impurities such as fine particles. There is no particular limitation on the gas dissolving apparatus used in the present invention, for example, an ejector type gas dissolving apparatus, an air diffusion type dissolving apparatus that diffuses gas into pure water, and a gas supplied to one side of a gas permeable membrane. Examples thereof include a gas permeable membrane type dissolving device that dissolves in pure water on the other side through a gas permeable membrane.
In the piping of the present invention, the cleaning water flowing out from the gas dissolving device is supplied through the main piping as a gas-liquid mixed fluid with undissolved oxidizing gas or reducing gas to the vicinity of the use point where the cleaning water is used. The When using an air diffusion type or gas permeable membrane type dissolution device, both the cleaning water and oxidizing gas or reducing gas flowing out from the gas dissolving device are introduced into the main pipe and sent in a gas-liquid mixed state. Be paid. In general, electronic materials factories have multiple use points, and cleaning water produced in one place is more effective than dissolving dissolved oxidizing gas or reducing gas in pure water at each use point. It is more advantageous in terms of equipment and economy to connect and supply the pipes to the respective use points. However, when the piping becomes longer, in the case of cleaning water in which a gas having self-decomposability such as ozone is dissolved, a decrease in concentration due to gas self-decomposition becomes a problem.
[0006]
When the oxidizing gas is ozone, the ozone-dissolved cleaning water that flows out of the gas dissolving device is supplied through the main pipe as a gas-liquid mixed fluid with undissolved ozone-containing gas. The dissolved ozone concentration of water can be made almost constant. FIG. 3 is an explanatory diagram of the ozone constant concentration holding mechanism. In FIG. 3, the horizontal axis represents the main pipe length, and the vertical axis represents the dissolved ozone concentration. When the ozone-containing gas is supplied to the pure water in the gas dissolving apparatus A, the ozone is dissolved in the pure water and the dissolved ozone concentration rapidly rises. However, when the concentration of ozone dissolved in pure water increases, ozone disappears due to self-decomposition in water. On the other hand, since ozone present in a gas state is more stable than ozone dissolved in water, ozone present in the undissolved gas accompanying the water flow dissolves in water. As a result, at point B, the amount of ozone that disappears due to autolysis in water and the amount of ozone that dissolves in the water from the accompanying undissolved gas are balanced, and the dissolved ozone concentration in the ozone-dissolved cleaning water is maintained at a substantially constant value. Be drunk. When ozone-dissolved cleaning water flows further downstream of the main pipe, the amount of ozone in the accompanying undissolved gas decreases, and at point C, the amount of ozone that disappears by self-decomposition in water and the accompanying undissolved gas The amount of ozone dissolved in the water becomes difficult to maintain a balance, and the concentration of dissolved ozone begins to decrease. By providing a branch pipe for taking out ozone-dissolved cleaning water between points B and C, ozone water having a predetermined concentration can be stably supplied to the use point even during long distance transfer.
Even if the oxidizing gas or reducing gas is a gas that does not have self-decomposability such as oxygen gas or hydrogen gas, the gas is sent to a gas dissolving device attached to the pipe of pure water, and an inline mixer or the like is used. When the gas-dissolved cleaning water is prepared directly in the main pipe, the cleaning water is transferred through the main pipe in the presence of an oxidizing gas or a reducing gas. In addition, even when gas-dissolved cleaning water is prepared by an aeration method or a gas permeable membrane method, by supplying an oxidizing gas or a reducing gas into the main pipe, always maintaining a gas-liquid equilibrium state, The gas concentration in the washing water can be stabilized.
[0007]
In the gas-dissolved cleaning water supply pipe of the present invention, the cleaning water in which the oxidizing gas or reducing gas is dissolved is transferred through the main pipe 12 in a gas-liquid mixed state in the presence of the oxidizing gas or reducing gas. In the vicinity of the use point, it branches off from the main pipe and is taken out from the branch pipe 13 attached downward. The branch pipe is preferably arranged at a position where the flow in the main pipe is stable, the gas phase exists only in the upper part of the main pipe, and no bubbles are involved in the water flow. Since the main pipe usually has rising and falling parts, avoid such a main pipe that is nearly vertical, the distance from the vertical part is 50 cm or more, and the main pipe is installed almost horizontally. It is preferable to arrange a branch pipe at the position. By attaching the branch pipe downward from the main pipe, it is possible to take out only cleaning water that does not contain bubbles without entraining the gas phase that gathers and moves in the upper part of the pipe in the main pipe.
In the gas-dissolved cleaning water supply pipe of the present invention, a flow rate adjustment valve 14 is attached to the branch pipe. There is no restriction | limiting in particular in the flow regulating valve to be used, For example, a ball-shaped valve, a needle valve, a butterfly valve, etc. can be used as a throttle valve. By providing a flow rate adjustment valve in the branch pipe and adjusting the flow rate of the washing water in the branch pipe, it is possible to prevent entrainment of bubbles from the main pipe. The flow rate of the wash water in the branch pipe is preferably smaller than the flow rate of the wash water in the main pipe, more preferably less than 85% of the flow rate of the wash water in the main pipe, and the wash water in the main pipe. More preferably, it is less than 70% of the flow rate.
By using the gas-dissolved cleaning water supply pipe of the present invention, gas-liquid separation is completely performed without providing a gas-liquid separation device such as a buffer tank in the vicinity of the use point, and oxidizing gas or reducing gas containing no bubbles is generated. Since the dissolved washing water can be taken out, the equipment cost and the management cost can be reduced. In addition, there is no possibility of contamination of the washing water due to poor management of the gas-liquid separator.
[0008]
【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.
Example 1
FIG. 4 is a schematic view of the test piping used in this example. An ozone dissolving ejector 15 was connected to the pure water supply pipe as an ozone dissolving apparatus, and a translucent polyvinylidene fluoride pipe having an inner diameter of 20 mm was further connected to the ozone dissolving ejector to form a main pipe 16. A branch pipe 17 made of a translucent polyvinylidene fluoride pipe having an inner diameter of 20 mm is attached downward at a position 70 cm away from the ozone dissolution ejector, and a transparent Teflon tube 19 having an inner diameter of 20 mm is connected via a Teflon connector 18. . A needle valve 20 having a liquid contact portion made of Teflon was provided in the middle of the transparent Teflon tube, and the end of the transparent Teflon tube was stored in a measuring cylinder 21 having a capacity of 10 liters.
Pure water was supplied to the pure water supply pipe using a metering pump (not shown). As an ozone generator (not shown), a silent discharge ozone generator SG-01CHU manufactured by Sumitomo Precision Industries, Ltd. was used. A mixed gas of high-purity oxygen gas and a small amount of high-purity nitrogen gas was fed into the ozone generator to generate an ozone-containing gas having an ozone content of 10% by weight. The ozone-containing gas was fed into an ozone dissolution ejector so that the mixing ratio of pure water and ozone-containing gas was 3.5 (L / G capacity ratio).
When the water flow rate of the main pipe is 412 liters / hr, the flow rate is 0.36 m / sec, the water flow rate of the branch pipes is 138 liters / hr, and the flow rate is 0.12 m / sec, it is visually observed both in the transparent Teflon tube and in the graduated cylinder. In some cases, the presence of bubbles was not observed.
The amount of pure water supplied by the metering pump was gradually decreased, the needle valve was opened, and the amount of ozone-dissolved cleaning water taken out to the branch pipe was gradually increased. Even when the main pipe water flow rate is 370 liters / hr, the flow rate is 0.33 m / sec, the branch pipe water flow rate is 180 liters / hr, and the flow rate is 0.16 m / sec, the main pipe water flow rate is 334 liters / hr and the flow rate is 0.3. Even at 30 m / sec, branch pipe water flow rate of 216 liters / hr, and flow rate of 0.19 m / sec, the presence of bubbles was not observed by visual observation in the transparent Teflon tube and the graduated cylinder.
Furthermore, when the amount of pure water supplied by the metering pump was reduced, the needle valve was opened, and the amount of ozone-dissolved cleaning water taken out into the branch pipe was increased, the water flow rate of the main pipe was 298 liters / hr, and the flow rate was 0.26 m. When the water flow rate was 252 liters / hr and the flow rate was 0.22 m / sec, the bubble migration into the transparent Teflon tube and the graduated cylinder was observed.
Table 1 shows the main pipe water flow rate and flow velocity V ₁ , the branch pipe water flow rate and flow velocity V ₂ , the flow velocity ratio V ₂ / V _1, and the presence or absence of bubbles observed visually.
[0009]
[Table 1]

[0010]
From the results in Table ₁ , when the ratio of the flow velocity V _{2 of the} branch pipe to the flow velocity V ₁ of the main pipe, V ₂ / V ₁ , is 0.85 or more, bubbles migrate into the branch pipe, but V ₂ / V _By setting ₁ to less than 0.85, gas-dissolved cleaning water without entrainment of bubbles can be taken out from the main pipe without using a gas-liquid separator such as a buffer tank, and can be used at the point of use. I understand.
[0011]
【The invention's effect】
According to the gas-dissolved cleaning water supply pipe of the present invention, the gas-dissolved cleaning water that passes the oxidizing gas such as ozone-containing gas, oxygen gas, hydrogen gas or reducing gas and pure water while mixing in the main pipe. In the supply system, it is possible to obtain gas-dissolved cleaning water that does not involve entrainment of gas-liquid separated gas at the point of use without providing a gas-liquid separator in the branch pipe.
[Brief description of the drawings]
FIG. 1 is a process flow diagram of a conventional ozone-dissolved cleaning water supply system.
FIG. 2 is an explanatory view of one aspect of the piping of the present invention.
FIG. 3 is an explanatory diagram of a constant ozone concentration holding mechanism.
FIG. 4 is a schematic diagram of test piping used in Examples.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Oxygen gas container 2 Nitrogen gas container 3 Ozone generator 4 Ozone dissolution device 5 Main piping 6 Branch piping 7 Use point 8 Ozone decomposition device 9 Gas-liquid separation device 10 Water supply piping 11 Gas dissolution device 12 Main piping 13 Branch piping 14 Flow rate Control valve 15 Ejector for ozone dissolution 16 Main pipe 17 Branch pipe 18 Teflon connector 19 Transparent Teflon tube 20 Needle valve 21 Female cylinder

Claims (2)

In supply pipe for supplying gas dissolved cleaning water to the use point, the wash water in the pure water to dissolve the ozone gas, the main pipe for transferring in the presence of ozone gas, a substantially horizontal branch pipe for taking out the washing water from the main pipe A gas-dissolved cleaning water supply pipe, characterized in that it is attached downward from the main pipe and a flow control valve is attached to the branch pipe.   2. The gas-dissolved cleaning water supply method using the gas-dissolved cleaning water supply pipe according to claim 1, wherein the flow rate adjustment valve attached to the branch pipe adjusts the flow rate of cleaning water in the branch pipe to be smaller than the flow rate of cleaning in the main pipe. A gas-dissolved cleaning water supply method comprising:

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