阅读说明：本技术 洗涤水处理装置和除菌、净水处理装置以及洗涤水处理方法 (Washing water treatment apparatus, sterilizing and purifying water treatment apparatus, and washing water treatment method ) 是由 樱井贵子 矢田胜久 于 2020-04-27 设计创作，主要内容包括：本发明提供洗涤水处理装置、除菌/净水处理装置、洗涤水处理方法,该洗涤水处理装置可有效地进行再利用的纯水中所含的细菌的杀菌处理和有机物的分解处理,同时可将纯水的TOC浓度抑制在规定值以下,利用简单的结构可长时间运转。洗涤水处理装置(12)、除菌/净水处理装置、洗涤方法,该洗涤水处理装置(12)的特征在于：具备控制装置(16),该控制装置(16)由存储部(16b)和控制部(16a)构成,该存储部(16b)存储有运算式,该运算式可根据被处理水的臭氧浓度和TOC浓度求出被处理水的排水量和纯水的供给量,该控制部(16a)控制臭氧供给部和TOC调节设备(22),依据由运算式求得的结果,通过TOC浓度调节设备(22)对被处理水进行纯水的供给、或者进行被处理水的排水和纯水的供给,以将洗涤处理部(11)中使用的洗涤水的TOC浓度抑制在规定值以下。(The invention provides a washing water treatment device, a sterilizing/purifying water treatment device, and a washing water treatment method, wherein the washing water treatment device can effectively perform sterilization treatment of bacteria and decomposition treatment of organic matters contained in reused pure water, and can restrain TOC concentration of the pure water below a specified value, and can operate for a long time by a simple structure. A washing water treatment device (12), a sterilization/purification water treatment device, and a washing method, wherein the washing water treatment device (12) is characterized in that: the washing machine is provided with a control device (16), the control device (16) is composed of a storage part (16b) and a control part (16a), the storage part (16b) stores an operational expression, the operational expression can obtain the water discharge amount of the water to be treated and the supply amount of pure water according to the ozone concentration and the TOC concentration of the water to be treated, the control part (16a) controls the ozone supply part and the TOC adjusting device (22), and the TOC concentration adjusting device (22) supplies pure water to the water to be treated or supplies the water to be treated and the pure water according to the result obtained by the operational expression, so that the TOC concentration of the washing water used in the washing treatment part (11) is controlled below a specified value.)

1. A washing water treatment apparatus for sterilizing and purifying pure water obtained by washing a member to be treated in a washing treatment unit and reusing the purified water, comprising: a washing water storage unit for allowing pure water after washing to flow as water to be treated from the washing treatment unit and a filtration mechanism unit for connecting the washing water storage unit and a sterilization purification unit to allow circulation of the water to be treated, wherein a circulation flow path connecting the filtration mechanism unit and the washing treatment unit is provided with a TOC concentration adjustment device for discharging the water to be treated and supplying the pure water, the washing water treatment apparatus comprising a control device including: a storage unit for storing a calculation formula capable of determining a discharge amount of the water to be treated and a supply amount of pure water from an ozone water concentration and a TOC concentration of the water to be treated; and a controller for controlling the ozone supply unit and the TOC concentration adjusting device, and for controlling the TOC concentration of the washing water used in the washing unit to be equal to or less than a predetermined value by supplying pure water or by discharging the water and supplying pure water to the water to be treated by the TOC concentration adjusting device based on a result obtained by the arithmetic expression.

2. Degerming/water purification unit, its characterized in that: the washing water treatment apparatus according to claim 1, wherein the sterilizing and purifying unit includes an ozone supply unit for supplying ozone and an ultraviolet irradiation unit for irradiating ultraviolet rays, and generates hydroxyl radicals to sterilize the water to be treated flowing from the washing water treatment unit and decompose organic substances.

3. A method for treating washing water using the washing treatment apparatus according to claim 1, characterized in that: and a controller for controlling the TOC concentration adjusting means to supply the pure water and the drained water of the water to be treated in the amount obtained by controlling the TOC concentration adjusting means so as to suppress the TOC concentration of the washing water used in the washing unit to a predetermined value or less, thereby suppressing the TOC concentration of the washing water used in the washing unit to a predetermined value or less.

4. A method for treating washing water using the washing treatment apparatus according to claim 1, characterized in that: when pure water of an amount corresponding to the amount of washing water naturally reduced when the washing treatment of the member to be washed is performed in the washing treatment unit is supplied, the ratio of the ON time for supplying the ozone of the predetermined supply amount to the ozone supply unit, which is required to suppress the TOC concentration of the washing water used in the washing treatment unit to be less than the predetermined value, to the OFF time for stopping the supply of the ozone is determined based ON the operation formula stored in the storage unit of the control device, and the control unit of the control device controls the ozone supply unit to change the ozone supply amount by the predetermined amount based ON the determined ratio, and controls the TOC concentration adjusting device to supply pure water of an amount corresponding to the naturally reduced amount of the washing water, thereby suppressing the TOC concentration of the washing water used in the washing treatment unit to be less than the predetermined value.

5. The washing water treatment apparatus according to claim 1, wherein the arithmetic expression is calculated using a data table.

6. The washing water treatment method according to claim 3 or 4, wherein the arithmetic expression is calculated using a data table.

Technical Field

The present invention relates to a washing water treatment apparatus which purifies and reuses pure water used in a washing step of a plating process for semiconductor manufacturing, liquid crystal manufacturing, and electronic parts, and a sterilizing/purifying water treatment apparatus and a washing water treatment method.

Background

In a washing step in the production of semiconductor elements or liquid crystal glass or in the plating treatment of electronic parts, a large amount of pure water is used for washing semiconductor wafer substrates, liquid crystal glass substrates, plated electronic parts, and the like, but recovery and reuse of pure water used for washing are widely performed from the viewpoint of reducing the load on the environment, effective use of water resources, and the like.

In a manufacturing process of a semiconductor element or a manufacturing process of liquid crystal glass, an organic solvent is often used in stripping of a photoresist or the like, and pure water (hereinafter, referred to as "washing water") used in a washing process of a semiconductor element or liquid crystal glass is mixed with organic substances such as foreign matters, alcohols, surfactants, and the like, and therefore, when the washing water is recovered and reused in a production process of a semiconductor, it is necessary to remove solid particles or organic substances contained in the washing water.

When washing water containing organic substances is used in a washing step in the production of semiconductor elements or liquid crystal glass, the organic substances adhering to the object to be washed cause defects in circuit patterns and the like on the substrate surface, or cause carbonization in a subsequent heat treatment step to cause insulation failure, resulting in deterioration in product quality or yield. In addition, when washing water containing organic substances is used in a washing step in a plating process of electronic parts, organic substances adhering to products cause short circuits of circuits and the like, and thus quality deterioration of products and yield deterioration occur.

However, in the above-described washing step, although the washing water is recovered and filtered to remove solid particles or organic substances contained in the washing water, and then reused as pure water, even in pure water containing almost no bacteria at first, bacteria originally adhering to the apparatus or the object to be washed and bacteria present in the atmosphere enter the pure water, and bacteria of a type that proliferates even under low nutrition proliferate during the recovery and reuse of the washing water, thereby contaminating the pure water, a storage tank for washing water, and a pipe circulating in these tanks.

Since bacteria are also organic substances, when pure water contaminated with bacteria is used in a washing step in the production of semiconductor elements or liquid crystal glass or in a washing step in the plating treatment of electronic parts, defects occur in circuit patterns or the like on the substrate surface, short circuits occur in circuits, and the like, and the quality of products and the yield are deteriorated.

Therefore, in order to maintain these bacteria inevitably present in the pure water at an extremely low level, it is necessary to periodically stop the operation of the manufacturing apparatus, perform sterilization and washing treatment using a bactericide such as sodium hypochlorite in a storage tank of the pure water or a storage tank of the washing water in a washing apparatus (hereinafter referred to as "washing treatment section"), and in a pipe circulating between these tanks, or wipe off a biofilm adhering to a wall surface of the storage tank, and perform thorough post-washing of the inside of the apparatus using the pure water so that the inside of the washing treatment section does not have the bactericide left, and fill the washing treatment section with new pure water.

Since pure water is expensive, frequent exchange of pure water increases the production cost of the product, and sterilization in the washing treatment unit performed by periodically stopping the production apparatus decreases the operating rate of the production apparatus, which increases the production cost of the product.

In addition, when the washing water used in the washing step is recovered and reused, large organic substances in the washing water are generally captured and removed by a filter device such as a hollow fiber membrane filter or activated carbon, and then the washing water is brought into contact with an ion exchange resin (cation exchange resin or anion exchange resin) to remove ions in the washing water, and then the washing water is reused as pure water.

Conventionally, it has been known that ozone injection is effective as a method for sterilizing bacteria in pure water when pure water is recycled, and for example, patent document 1 proposes an ultrapure water production apparatus in which an ozone injection device is attached to a pipe for returning ultrapure water not used at a use point (use point) to an ultrapure water tank in order to prevent bacteria from being generated in the recycled ultrapure water, and ozone is injected into the ultrapure water by the ozone injection device to sterilize the ultrapure water at all times.

Conventionally, pure water and ultrapure water have been defined only in terms of specific resistance (electrical conductivity), but since the demand for water quality of pure water and ultrapure water has been increasing, the amount of Organic substances expressed by Total Organic Carbon (TOC) has recently been defined as an index for pure water and ultrapure water, and it is required that TOC in pure water is 1.0mg/L or less and TOC in ultrapure water is 0.01mg/L or less, but when ozone-containing pure water comes into contact with a resin-made site such as a pipe, for example, there is a problem as follows: the organic material of the resin elutes, resulting in an increase in the TOC concentration of pure water and deterioration of the resin.

As a technique for supplying ozone to pure water to sterilize bacteria in the pure water and to prevent the increase in the TOC concentration of the pure water, patent document 2 proposes an ultrapure water production supply apparatus which continuously injects low-concentration ozone to an appropriate position of a circulation line to sterilize bacteria in ultrapure water while operating continuously, decomposes residual ozone in ultrapure water by a low-pressure ultraviolet ozone decomposition device provided on the downstream side of the injection position, and supplies ultrapure water having an extremely reduced number of bacteria and TOC concentration to a point of use.

Patent document 3 proposes an ozone-containing water treatment apparatus which, in order to treat residual ozone in water, can reliably remove residual ozone and dissolved oxygen and efficiently remove hydrogen peroxide, which is a by-product of ultraviolet irradiation, by combining an ultraviolet irradiation apparatus, a degasser, a catalyst resin apparatus, or an activated carbon decomposition apparatus, and can be used in combination in a process for producing washing water in the electronics industry.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2-261594;

patent document 2: japanese patent laid-open publication No. 2-144195;

patent document 3: japanese patent laid-open No. 6-254549.

Disclosure of Invention

Problems to be solved by the invention

However, in the ultrapure water production and supply apparatus of patent document 2, the pure water existing between the low-pressure ultraviolet ozonolysis apparatus and the ozone injection point does not contain ozone, and even in the ozone-containing water treatment apparatus of patent document 3, the pure water existing between the catalyst resin apparatus or the activated carbon separation apparatus and the ozone injection point does not contain ozone, and therefore, the possibility that bacteria adhering to the object to be cleaned propagate at the use point or in the piping as the deodorizing oxygen zone cannot be eliminated. When bacteria are propagated in these places, the quality of the product or the yield is deteriorated, and the filtration performance and the ion exchange capacity of the filtration membrane or the ion exchange resin are deteriorated, so that frequent exchange or regular washing and sterilization of the apparatus is required, and the operation rate is lowered.

Further, if slime is generated in the filter device (filter) or the ion exchange resin device constituting the filter mechanism due to bacteria present in the device, the flow rate passing through the filter mechanism is reduced, and there is a problem that the filtration performance is reduced or the function of the ion exchange resin device cannot be exhibited.

In order to prevent TOC from being eluted from a resin pipe or a deionized water tank between an ozone supply unit and an inlet of a membrane degasser in the ultrapure water containing ozone, the method and apparatus for ozone sterilization of ultrapure water of patent document 2 use a stainless steel material whose surface is mirror-finished by electric field polishing or the like for the deionized water tank and the pipe from the ozone supply unit to the inlet of the membrane degasser, and therefore the apparatus is expensive and the production cost is increased.

The present invention has been made to solve the above problems, and an object of the present invention is to provide: a washing water treatment apparatus, a sterilizing/purifying water treatment apparatus, and a washing water treatment method, which can effectively perform sterilization treatment of bacteria and decomposition treatment of organic substances contained in reused pure water, and can suppress TOC concentration of pure water to a predetermined value or less, and can operate for a long time with a simple structure.

Means for solving the problems

In order to achieve the above object, the invention according to claim 1 is a washing water treatment apparatus for performing a sterilization and purification treatment of pure water, which is a member to be treated in a washing treatment unit, and reusing the pure water, wherein a washing water storage unit for allowing pure water after washing to flow as water to be treated from the washing treatment unit and a filtering mechanism unit for allowing the water to be treated to circulate are connected, and a TOC concentration adjusting device for supplying pure water and draining water of the water to be treated is provided on a circulation flow path connecting the filtering mechanism unit and the washing treatment unit, the washing water treatment apparatus including a control device including: a storage unit for storing a calculation formula capable of determining a discharge amount of the water to be treated and a supply amount of pure water from an ozone water concentration and a TOC concentration of the water to be treated; and a controller for controlling the ozone supply unit and the TOC concentration adjusting device, and for controlling the TOC concentration of the washing water used in the washing treatment unit to be less than or equal to a predetermined value by supplying pure water to the water to be treated or by discharging the water and supplying the pure water to the water to be treated by the TOC concentration adjusting device based on a result obtained by the arithmetic expression.

The invention according to claim 2 is a sterilizing/water-purifying treatment apparatus, wherein the sterilizing/purifying unit in the washing water treatment apparatus according to claim 1 includes an ozone supply unit for supplying ozone and an ultraviolet irradiation unit for irradiating ultraviolet rays, and generates hydroxyl radicals to sterilize water to be treated flowing from the washing water treatment unit and decompose organic substances.

The invention according to claim 3 is a washing water treatment method using a washing treatment apparatus, wherein a water discharge amount of water to be treated and a supply amount of pure water required to suppress a TOC concentration of washing water used in the washing treatment unit to a predetermined value or less when a predetermined amount of ozone is continuously supplied from an ozone supply unit are determined based on an arithmetic expression stored in a storage unit of a control apparatus, and the control unit of the control apparatus controls a TOC concentration adjusting device to perform the determined amount of water to be treated discharge and pure water supply so as to suppress the TOC concentration of washing water used in the washing treatment unit to the predetermined value or less.

The invention according to claim 4 is a method for treating washing water using a washing treatment apparatus, wherein, when pure water is supplied in an amount corresponding to the amount of washing water naturally reduced when the member to be washed is washed in the washing processing part according to the operation formula stored in the storage part of the control device, the ratio of ON time for supplying a predetermined amount of ozone to OFF time for stopping ozone supply by the ozone supply unit, which is required to suppress TOC concentration of washing water used in the washing treatment unit to a predetermined value or less, the control unit of the control device controls the ozone supply unit to change the amount of ozone supplied by a predetermined amount according to the determined ratio, while controlling the TOC concentration adjusting device to supply pure water in an amount equivalent to the natural decrement of the washing water, thereby, the TOC concentration of the washing water used in the washing processing part is controlled below a specified value.

The invention according to claim 5 is a washing water treatment apparatus, wherein the operation formula is calculated using a data table.

The invention according to claim 6 is a washing water treatment method, wherein the operation formula is calculated using a data table.

Effects of the invention

According to the invention of claim 1, after the sterilization of bacteria contained in the water to be treated and the filtration of solid particles or organic matter are performed by the washing water treatment apparatus, the supply of pure water, the drainage of the water to be treated, and the supply of pure water are performed by the TOC concentration adjusting means in accordance with the ozone water concentration and TOC concentration of the water to be treated, so that the water to be treated can be returned to the washing treatment unit (point of use) with the TOC concentration suppressed to a predetermined concentration or less, and therefore, products such as electronic components and liquid crystal glass substrates brought into the washing treatment unit can be washed with the washing water satisfying the water quality requirement, and deterioration in the quality of the products can be prevented, and the production yield can be improved.

Further, since the water to be treated present in the washing water treatment apparatus contains ozone at a low concentration, the growth of bacteria in the washing water treatment apparatus or in the piping can be suppressed, and therefore, clogging of the filter mechanism portion and deterioration of the function of the ion exchange resin due to bacteria are less likely to occur, and the life of the filter can be prolonged. In addition, since the growth of bacteria is suppressed, the generation of a biofilm in the filter mechanism can be suppressed, and as a result, the interval between washing and cleaning of the washing water treatment apparatus can be extended.

Further, since the initially set operational expression is set in an environment where ozone water of high concentration is used, which is not used in industry at first, and a member (resin) of which TOC is easily eluted is used, the ozone water concentration is lower than the set condition of the operational expression, and when the ozone water is used in an environment where a member of which TOC is not easily eluted, the ozone water can be used as it is without replacement. Further, if the water treatment environment (the amount of treated water, the current amount of pure water supplied, and the current concentration of ozone water) in which the washing water treatment apparatus is actually used is known from the arithmetic expression, the duration of the concentration of ozone water necessary for the sterilization purification treatment can be determined.

Further, by supplying ozone through the ozone supply unit while suppressing the concentration of the residual ozone water after the treatment to less than 5.37mg/L, the organic matter such as bacteria in the water to be treated is purified by ozone and reused, and the inside of the filter mechanism unit is sterilized, and the reaction of the resin member and the like in the flow path after the filter mechanism unit with ozone is suppressed to prevent deterioration, thereby making it possible to extend the life of the entire apparatus.

According to the invention of claim 2, the sterilizing and purifying unit is a sterilizing and purifying water treatment apparatus including an ozone supply unit for supplying ozone and an ultraviolet irradiation unit for irradiating ultraviolet rays, and is configured to generate hydroxyl radicals to sterilize water to be treated flowing from the washing treatment apparatus and decompose organic substances, thereby sterilizing bacteria in the washing water and decomposing dead bodies of the sterilized bacteria and organic substances dissolved in the washing water, and efficiently purifying the washing water.

According to the invention of claim 3, when a predetermined amount of ozone is continuously supplied from the ozone supply unit, the TOC concentration adjusting means discharges the water to be treated and supplies the pure water in accordance with the discharge amount of the water to be treated and the supply amount of the pure water obtained from the arithmetic expression based on the ozone water concentration and the TOC concentration of the water to be treated, and the TOC concentration of the water to be treated returned to the washing unit is suppressed to a predetermined concentration or less.

Further, since the total supply amount of ozone is increased by continuously supplying a predetermined amount of ozone, for example, a large-sized member to be treated can be washed, and the water to be treated having a large amount of bacteria or organic substances mixed therein can be effectively sterilized and purified.

According to the invention according to claim 4, since the TOC concentration of the water to be treated returned to the washing processing unit can be suppressed to the predetermined value or less by supplying pure water corresponding to the amount of the washing water which is naturally reduced when the washing processing of the member to be washed is performed in the washing processing unit by the TOC concentration adjusting means and changing the supply amount of ozone by the predetermined amount from the ozone supply unit, the product such as an electronic component or a liquid crystal glass substrate brought into the washing processing unit can be washed by pure water having stable water quality, and therefore, the deterioration of the quality of the product can be prevented and the yield in manufacturing can be improved.

Further, since the supply amount of pure water is an amount corresponding to the amount naturally reduced in the washing process of the member to be processed, the amount of expensive pure water can be minimized to reduce the washing cost. Further, since a predetermined amount of ozone is intermittently supplied, the total amount of ozone supplied is small, and thus, for example, a small member to be treated can be washed, and water to be treated, which does not have a large amount of bacteria or organic substances mixed therein, can be sterilized and purified at low cost.

According to the invention of claim 5, since the operation formula can be operated using the data table, the operation processing can be performed quickly, and the TOC concentration can be adjusted quickly in the washing water treatment apparatus.

According to the invention of claim 6, since the operation formula can be operated using the data table, the operation processing can be performed quickly, and the TOC concentration can be adjusted quickly in the washing water treatment method.

Drawings

FIG. 1 is a schematic view showing an example of a washing water treatment apparatus according to the present invention.

FIG. 2 is a block diagram showing a deterioration test apparatus for an ion exchange resin/filter apparatus.

FIG. 3 is a graph showing the change in concentration of initial ozonated water at 5.37 mg/L.

FIG. 4 is a graph showing the change in concentration of initial ozonated water at 12.5 mg/L.

FIG. 5 is a photomicrograph of a filter having an ozone water concentration of 0 mg/L.

FIG. 6 is a photomicrograph of a filter having an ozone water concentration of 5.5 mg/L.

FIG. 7 is a photomicrograph of a filter having an ozone water concentration of 12.7 mg/L.

FIG. 8 is a block diagram of a TOC elution test.

FIG. 9 is a block diagram of a TOC elution test with a part omitted.

FIG. 10 is a graph showing the measured value of TOC concentration per time when the amount of ozone generation was varied.

FIG. 11 is a graph showing the relationship between the ozone water concentration and the TOC elution amount.

FIG. 12 is a graph showing measured values of the ozone supply amount and the ozone water concentration.

FIG. 13 is a graph showing the change in the concentration of ozone water during an intermittent operation in which ozone supply/stop is repeated.

FIG. 14 is a graph showing the results of a simulation of the TOC concentration of treated water in the case where a certain amount of treated water is continuously discharged and a certain amount of pure water is continuously supplied while varying the ozone supply time.

FIG. 15 is a graph showing the results of a simulation of the concentration of ozone water in treated water in the case where a certain amount of ozone is intermittently supplied.

FIG. 16 is a graph showing the results of a simulation of TOC concentration of water to be treated in the case where pure water is replenished with a certain amount of ozone intermittently and in the case where no replenishment is performed.

FIG. 17 is a schematic view showing a case where the washing water treatment apparatus of the present invention is applied to a final washing water tank among a plurality of washing water tanks in a plating process step.

FIG. 18 is a schematic view showing a case where the washing water treatment apparatus of the present invention is applied to a semiconductor processing container.

FIG. 19 is a schematic view showing a case where the washing water treatment apparatus of the present invention is applied to a glass substrate manufacturing apparatus.

Detailed Description

Hereinafter, a washing water treatment apparatus and a washing water treatment method according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing the constitution of one embodiment of a washing water treatment apparatus of the present invention.

In fig. 1, a washing water treatment apparatus 12 includes a washing water storage 13, a sterilizing and purifying unit 14, a filter mechanism 15, and a control device 16, the washing water storage 13 and the sterilizing and purifying unit 14 are connected to each other in a circulating manner through an inflow passage 17 and an outflow passage 18, the washing water storage 13 and the filter mechanism 15 are connected to each other through a filter passage 19, the washing treatment unit 11 and the washing water storage 13, and the filter mechanism 15 and the washing treatment unit 11 are connected to each other through a circulating passage 20, and a TOC concentration measuring device 21 and a TOC concentration adjusting device 22 are provided in the circulating passage 20 at the rear stage of the filter mechanism 15.

The washing water storage 13 is a water tank for allowing pure water used for the washing process of the member to be processed in the washing processing unit 11 to flow into and store the pure water as water to be processed through the circulation flow path 20. An inflow passage 17 and an outflow passage 18 provided to be able to circulate between the washing water storage unit 13 and the sterilizing and purifying unit 14, and a filtration passage 19 leading to the filtration mechanism 15 are connected to the washing water storage unit 13.

The sterilizing and purifying unit 14 is a unit that performs sterilizing and purifying treatment on the water to be treated supplied from the washing water storage unit 13 by a pump, not shown, provided inside the unit. The water to be treated stored in the washing water storage unit 13 is subjected to the sterilization/purification treatment while circulating between the washing water storage unit 13 and the sterilization/purification unit 14 through the inflow passage 17 and the outflow passage 18 that are connected to each other so as to be able to circulate between the sterilization/purification unit 14 and the washing water storage unit 14. The circulation of the water to be treated between the washing water storage 13 and the sterilizing and purifying unit 14 is performed by a not-shown circulation pump provided in the sterilizing and purifying unit 14.

The bacteria elimination and purification unit 14 includes: an ozone supply unit for supplying ozone, an ultraviolet irradiation unit for irradiating ultraviolet rays, and a photocatalyst action unit for acting a photocatalyst, wherein the functions are organically combined to perform a sterilization and purification treatment of water to be treated. The sterilization/purification unit 14 may be provided with at least an ozone supply unit, and the ultraviolet irradiation unit and the photocatalyst action unit may be omitted as necessary. The ozone supply unit, the ultraviolet irradiation unit, and the photocatalyst action unit will be briefly described below.

The ozone supply unit is a part for supplying ozone to the water to be treated supplied from the washing water storage unit 13 through the inflow channel 17, and includes an ozone generator for generating ozone using air as a raw material and an injector provided in the inflow channel 17 for supplying and mixing the ozone to the water to be treated flowing through the channel.

The ozone generator has a discharge gap between a ground electrode and a dielectric to which a high-voltage electrode is attached, and generates ozone in air flowing through the discharge gap by applying a high voltage between the ground electrode and the dielectric to cause discharge. The ejector is made of a resin such as a fluororesin, ceramic, or metal, and mixes the water to be treated flowing through the inflow channel 17 with ozone (and dissolved oxygen) supplied from an ozone generator to prepare a fine bubble-like mixed liquid (ozone water).

The ultraviolet irradiation unit and the photocatalyst action unit for acting a photocatalyst are integrated into an ultraviolet/photocatalyst unit. The ultraviolet/photocatalyst unit has an ultraviolet light source at the center, and an inner glass tube for protection is provided on the outer peripheral side of the ultraviolet light source. An outer glass tube having a predetermined inner diameter is provided on the outer peripheral side of the inner glass tube on the outer periphery of the ultraviolet light source, and a flow path for water to be treated is formed between the outer glass tube and the inner glass tube. A photocatalyst serving as a photocatalyst action part is disposed in the flow path.

The photocatalyst is a photocatalyst that does not peel off by oxidizing the surface of a metallic titanium substrate to produce titanium oxide, and is formed by, for example, coating the surface side of a material such as titanium or a titanium alloy made of mesh, a titanium wire, an aggregate of fibrous titanium materials, other porous titanium materials, or the like with titanium oxide.

The whole unit is miniaturized by forming a structure in which an ultraviolet light source is disposed in the central portion of an ultraviolet/photocatalyst unit, and the water to be treated is effectively irradiated with ultraviolet rays to sterilize the water to be treated, and the organic matter is decomposed to perform sterilization purification treatment.

As shown in fig. 1, the filter mechanism 15 is composed of a filter 26 and an ion exchange resin 27. The filter device 26 may house a filter such as a hollow fiber membrane filter or an activated carbon filter, but in order to efficiently filter bacteria contained in the water to be treated or organic substances of dead bodies containing bacteria, a hollow fiber membrane such as a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane) is preferably used. As a container of the filter device 26 in which these hollow fiber membranes are incorporated, materials such as PVC are often used when the water to be treated is pure water, and materials such as PVC are also used when the water to be treated is ultrapure water.

The ion exchange resin 27 is used for removing salt components such as calcium, sodium, chloride, and sulfuric acid in the water to be treated, which cannot be removed by the ozone treatment or the filtration treatment, and a cation exchange resin for exchanging cations and an anion exchange resin for exchanging anions (negative ions) may be used in combination. As the container of these ion exchange resins, materials such as FRP, Teflon (registered trademark) plated or coated on stainless steel or iron, and the like are often used in the case where the water to be treated is pure water, and these materials are also used in the case where the water to be treated is ultrapure water.

The control device 16 includes a control unit 16a and a storage unit 16 b. The controller 16a is provided to control the ozone supply unit and the TOC concentration adjusting device 21 of the sterilization/purification unit 14, and the storage unit 16b stores an arithmetic expression for determining the supply of the water to be treated to the pure water or the supply amount of the discharged water of the water to be treated and the pure water. In the figure, the dashed lines connecting the control device 16, the bacteria elimination and purification unit 14, the TOC concentration measurement device 21, and the TOC concentration adjustment device 22 indicate signal transmission paths.

Here, the present inventors confirmed that, in the course of conducting research and development of the purification apparatus and the purification method: in order to prevent the increase of bacteria at the use point, it is not enough to perform sterilization and purification only by ozone, and it is necessary to supply ozone to the washing water storage part, and the purification treatment device is added to the existing washing device for the electronic parts processed by semiconductor manufacturing, liquid crystal, washing and plating, and can effectively perform purification treatment on the washing water so as to reuse the washing water for a long time.

On the other hand, it was also confirmed that: when ozone is present in the washing water storage unit, TOC is eluted from a resin impeller of a pump for circulating the water to be treated provided in the sterilizing and purifying unit, a resin filter case for storing a hollow fiber membrane filter of the filtering device, and a resin tank for storing an ion exchange resin.

In view of these circumstances, when the water to be treated in the washing water storage unit 13 is sterilized with ozone, it is necessary to prevent TOC from being eluted from the resin members due to ozone contained in the treated pure water in addition to sterilizing the treated pure water until the treated pure water is in a state suitable for reuse. Therefore, while the ozone water concentration is set to a value that can sterilize the treated water after treatment until the treated water can be reused, the ozone water concentration is suppressed to a value that can prevent elution of TOC from each of the resin members.

The storage unit 16b stores an arithmetic expression for determining the discharge amount of the water to be treated and the supply amount of the pure water from the ozone water concentration and the TOC concentration of the water to be treated. By controlling the amount of water discharged from the water treatment unit and the amount of pure water supplied by the controller 16a according to the arithmetic expression, the ozone water concentration can be maintained in a state where the treated water can be reused by sterilizing the treated water, and elution of TOC from the resin member can be suppressed.

In order to set the arithmetic expression of the storage unit 16b, it is required to set the ozone water concentration so that the treated water after treatment can be sterilized to a reusable state and to set a value capable of suppressing the TOC concentration as described above. In this case, the function is maintained by maximizing the sterilizing ability of the water to be treated and by minimizing the influence on the resin components such as the filter mechanism 15.

In order to obtain such treated water having the highest sterilization capacity and the highest concentration of ozone water, it is necessary to clarify the influence of the difference in the concentration of ozone water on the filter or ion exchange resin 27 in the washing water storage 13 and the washing water treatment apparatus 12, or on the resin members such as the FRP tank or the filter case, the impeller of the pump, and the O-ring which fill the container. Therefore, the filter device 26 and the ion exchange resin 27 were subjected to the ozone water degradation test. In the deterioration test, the conditions under which the filter 26 or the ion exchange resin 27 was deteriorated were confirmed by changing the ozone water concentration or the contact time with ozone, and the relationship between the ozone water concentration and the oxidative deterioration of the filter 26 or the ion exchange resin 27 was confirmed.

In this case, the desired ozone water concentration (mg/L) is obtained by setting the amount of ozone generated per unit time (g/hour). The present applicant speculates that the ozone generation amount for obtaining the optimum ozone water concentration is 2.0 g/hr, and by performing a test on the ozone water concentration at this time of 5.37mg/L, the concentration of residual ozone water after ozone treatment is suppressed to less than 5.37mg/L by the ozone supply unit. In contrast, the test was conducted for the case where the ozone generation amount was 0.3 g/hr (ozone water concentration was 1.31mg/L) and the case where the ozone generation amount was more than 2.0 g/hr (ozone water concentration was 5.37 mg/L). In this case, ion-exchanged water is used as the pure water for all the target water.

The conditions under which the ion exchange resin 27 and the filtration device (filter) 26 deteriorate were confirmed using the test apparatus 100 shown in fig. 2, and the relationship between these conditions and the oxidative deterioration of the ozone water concentration was clarified.

In the figure, PSA (oxygen concentrator) 101 was used as a generator of a gas raw material, the PSA was connected to an ozone generator 125 (ozone generator OZS-EP3-20, manufactured by japan research corporation), and ozone gas generated in the ozone generator 125 was dissolved under pressure by using a mixing pump 103 (Nikuni M20NPD04Z, manufactured by japan corporation), to produce high-concentration ozone water.

The ozone water produced in the ozone generating unit 136 that generates ozone is stored in the water tank 130, and the ozone water is sent to the ion exchange resin 27 or the filter device (filter) 26 via the water transfer pump 104. The flow meter 106 and the adjustment valve 136 provided in the path are adjusted to an appropriate flow rate, and water is passed through the ion exchange resin 27 or the filtration device 26.

The concentration of the ozone water stored in the test water tank 130 was measured as needed by using an ozone water concentration meter 110 (okitorec, ltd.) OZM-7000 LN.

In fig. 2, although the filters 26 and the ion exchange resins 27 are arranged in series in a set with respect to the flow path, a plurality of filters and ion exchange resins may be arranged in parallel.

In the deterioration test of the ion exchange resin 27 with ozone water, a PVC container was used as a container filled with the organic ion exchange resin AMBERLITE MB2 and the ion exchange resin 27.

In the deterioration test of the ion exchange resin 27 using the test apparatus 100, the test apparatus 100 was operated for 30 minutes with respect to the ion exchange water stored in the test water tank 130, and the ozone water concentration was measured. Thereafter, the water transfer pump 104 is operated to introduce ozone water to the ion exchange resin 27 at a predetermined concentration for a predetermined time. Various analyses were performed on the ion exchange resin 27 after the ozone water was introduced, and the degree of deterioration was confirmed.

Various conditions for carrying out the above test are as follows.

PSA air supply flow: 2.5-2.7L/min;

PSA gas supply pressure: 0.078-0.081 MPa;

mixing pump discharge pressure: 0.29 to 0.33 MPa;

flow of the ozone generator: 1.6-1.7L/min;

water quantity: 70L;

water passing time: 8 hours and 72 hours.

The change in the concentration of ozone water in the test performed by the test apparatus 100 is shown in the graphs of fig. 3 and 4. Fig. 3 shows the change of the ozone water concentration with respect to the operating time when the ozone water concentration is set to around 5.37mg/L, and fig. 4 shows the change of the ozone water concentration with respect to the operating time when the ozone water concentration is set to more than 5.37 mg/L. In both the graphs of fig. 3 and 4, water is supplied to the ion exchange resin 27 from the time point indicated by the arrow.

In the case of FIG. 3, the ozone water concentration at the time when the flow of the test water accumulated in the test water tank 130 to the ion exchange resin 27 was started by the ozone generator (ozone supply unit) 125 was 5.37 mg/L. After the ion exchange resin 27 was passed through with water, the ion exchange resin 27 reacted with ozone, and therefore the ozone water concentration decreased, and the average ozone water concentration in the water passage test was 4.07 mg/L. Since the influence of the reaction between the ion exchange resin 27 and ozone becomes large after the ion exchange resin 27 is supplied with water in this manner, the concentration of the residual ozone water treated by the ozone generator 125 should be suppressed to less than 5.37mg/L as a definition at the time of setting the ozone water concentration.

On the other hand, in the case of FIG. 4, the concentration of the ozonized water at the initial stage of water passage was about 12.5 mg/L. Immediately after the start of the water supply to the ion exchange resin 27, the ozone water concentration decreases due to the reaction of the ion exchange resin 27 with ozone as described above, and varies somewhat depending on the water temperature and the water supply time, but the ozone water concentration changes approximately from 6 to 9mg/L, and the average ozone water concentration after the water supply to the ion exchange resin 27 is 7.44 mg/L.

In this case, the ozone water concentration did not decrease to less than 5.37mg/L in any state from the initial stage of water supply until the lapse of the predetermined operation time (8 hours), and the ozone water concentration condition in the test of fig. 3 was not overlapped.

The analysis results of the ion exchange resin 27 based on the above test are shown below.

Regarding the influence of ozone on the ion exchange resin, when the ion exchange resin is oxidized by ozone, it is assumed that functional groups are dropped or a matrix of the resin is oxidized and expands. Therefore, as analysis items for grasping the deterioration, "total exchange capacity", "neutral salt decomposition capacity", and "water retention capacity" were measured.

The ion exchange resin used in the test was a mixed resin in which a cation exchange resin and an anion exchange resin were uniformly mixed, but the ion exchange resins were separated at the time of analysis, and various values were measured.

The test was roughly divided into 2 runs, and Table 1 shows the results of analysis of the ion exchange resin when the test was carried out with the ozone water concentration at the initial stage of water passage of 1.31mg/L and 5.37 mg/L. Table 1 shows the performance of the ion exchange resin in a state in which ozone water is not introduced, and thus the reference value of the performance is described.

When the concentration of ozone water at the initial stage of water supply was 1.31mg/L, the concentration of ozone water decreased since the ion exchange resin also reacted with ozone after the ozone water was supplied to the ion exchange resin, and the average concentration of ozone water in the water supply test was 0.68 mg/L.

[ Table 1]

In table 1, when the analytical values of reference value 1 and tests 1A and 1B were compared, although the reaction between the ion exchange resin and the ozone water was observed at a concentration of ozone water less than 5.37mg/L, no clear deterioration was observed in either of the cation exchange resin and the anion exchange resin in tests 1A and 1B as compared with the reference value with respect to the neutral salt decomposition amount and the water retention capacity, and the practical functionality as the ion exchange resin was ensured.

On the other hand, the results of the analysis of the case where the ozone water concentration was 5.37mg/L or more are shown in Table 2. Table 2 shows the reference values recommended in general, the "no water" state in which no ozone water was introduced, and various measured values of the ion exchange resin at the time when the water passage time was 8 hours or 72 hours when the ozone water concentration was 5.37mg/L or more (the initial water passage concentration was 12.5 mg/L).

[ Table 2]

In test 2A (12.5 mg/L of ozone water at the initial stage of water passage, 7.5mg/L of ozone water at the stage of water passage, and 8 hours of water passage time) in Table 2, it was confirmed that the cation exchange resin A had a lower ion exchange capacity than the reference value in terms of the neutral salt decomposition capacity. On the other hand, it was confirmed that the water retention capacity was higher than the upper limit of the reference value, and the resin was swollen and deteriorated by the oxidation action of ozone.

Therefore, the following steps are carried out: when the water passage time was further extended to 72 hours (test 2B), the total exchange capacity of the anion exchange resin B was also lower than the reference value, and the deterioration of the ion exchange resin was more advanced.

From the above, it can be seen that: the ion exchange capacity decreased as the water passage time of the ozone water extended, and under the conditions of this test, it was possible to determine whether or not the ion exchange resin was deteriorated in a state where the water passage time was 8 hours as compared with the reference value.

In this test, the TOC elution amount was also confirmed by measuring the particle size of the ion exchange resin and observing the ion exchange resin under a microscope after the ozone water was passed through. In particular, in the anion exchange resin, it was confirmed that: as the water passage time of the ozone water is prolonged, physical breakup occurs and the particle diameter becomes small. In addition, it was also confirmed that: the TOC concentration in the water passage test also increased with the passage of water for a longer period of time. This is believed to be due to: the organic polymer material constituting the ion exchange resin is oxidized by ozone, and the structure of the resin itself cannot be maintained, and the organic material as a material is eluted.

From the above, it can be seen that: when ozone water as an oxidizing agent is supplied to the ion exchange resin at an ozone water concentration of 7.5mg/L for 8 hours or more, there is a concern about a decrease in ion exchange performance and elution of organic substances, and it is considered to be practically difficult to use the ion exchange resin in this ozone water.

From the above, it can be seen that: receiving the results of table 1, if the ozone water concentration is less than 5.37mg/L, the sterilization effect can be maintained on the ion exchange resin contained in the filter mechanism unit, and the deterioration can be prevented without impairing the function, thereby reducing the exchange frequency of the ion exchange resin and prolonging the life of the apparatus.

Then, a deterioration test of the filter device 26 (filter) was performed using the test device 100 of fig. 2.

The high-concentration ozone water produced from pure water was supplied to the filter 26 while keeping the concentration thereof constant by the test apparatus 100, and the progress of deterioration of the filter 26 was confirmed when the contact time was changed.

The Filter used in the test was a shell-type NPH-NPP-10 Filter made by Filter, Japan, and the type of the Filter was CW-1 (made of polypropylene).

The procedure of the deterioration test of the filter device 26 by the test apparatus 100 was the same as that of the deterioration test of the ion exchange resin shown in [0081], and the filter through which the ozone water was passed was observed with a microscope on the surface.

Various conditions for carrying out the above test are as follows.

PSA air supply flow: 2.5-2.9L/min;

PSA gas supply pressure: 0.078-0.085 MPa;

mixing pump discharge pressure: 0.3 MPa;

flow of the ozone generator: 1.6L/min;

water quantity: 70L;

water passing time: 8 hours and 24 hours.

The filters 26 of the filter device after the test were subjected to optical observation and SEM observation with a microscope.

The conditions for observation were as follows.

An analytical instrument: and (3) optical observation: digital microscope (Keyence VHX-1000);

and (4) SEM observation: an electron beam microanalyzer (EPMA-1610, Shimadzu corporation);

the analysis method comprises the following steps: after the surface of the filter was optically observed, gold deposition (ion sputtering) was performed, and SEM observation was performed.

The photographs under microscope observation of the filter (type CW-1) of the filter unit of the above test are shown in FIGS. 5 to 7. In each figure, the upper stage shows an observation photograph under a microscope, and the lower stage shows an SEM photograph under an electron microscope. FIG. 5 shows a state where the water passage time is 0 hour (no load from the ozone water), FIG. 6 shows a state where 24 hours of water passage is performed at an average ozone water concentration of 5.5mg/L in the passage water, and FIG. 7 shows a state of the filter after 24 hours of water passage at an average ozone water concentration of 12.7mg/L in the passage water.

As a result of the observation photographs of fig. 5 to 7, it was confirmed from the electron microscope (SEM image) of the lower stage that: as the ozone water concentration increases, the breakage of the fiber surface and the adhesion of the broken fiber fragments to the surface increase, and the degradation of the polymer resin by ozone increases.

In fig. 6, although the ozone water concentration when water was passed was 5.5mg/L (corresponding to an ozone water concentration of 5.37mg/L), no significant deterioration was observed compared with the photograph of fig. 5 in which no load was applied to the ozone water, and it was determined that if the ozone water concentration was about 5.5mg/L (corresponding to 5.37mg/L), deterioration did not occur to such an extent that the performance of the filter was impaired. On the other hand, when the ozone water concentration exceeded 5.37mg/L and water was passed through at 12.7mg/L, significant deterioration of the filter surface was observed as shown in FIG. 7.

From the above, it can be seen that: in the above-described deterioration test of the filter device, if the ozone water concentration is less than 5.5mg/L, deterioration of the filter performance is not caused, and conversely, the sterilization function of the filter device (filter) constituting the filter mechanism portion is sufficiently exerted by the ozone remaining in the water to be treated, whereby slime of the filter can be prevented, the performance of the filter device (filter) can be maintained, the exchange frequency of the filter can be reduced, and the life of the device can be prolonged.

From the above, it can be seen that: in the case of a single filter device (filter), if the concentration of ozone water is less than 5.5mg/L, the sterilization effect can be maintained and the degradation can be prevented without impairing the function, and if the concentration of ozone water determined in the degradation test of the ion exchange resin is less than 5.37mg/L as a whole of the filter mechanism unit composed of the filter device (filter) and the ion exchange resin, the sterilization effect can be maintained as a whole of the filter mechanism unit and the degradation can be prevented without impairing the function, and furthermore, the exchange frequency of the filter membrane or the ion exchange resin can be reduced and the life of the device can be prolonged.

Then, experiments were conducted to clarify the relationship between the ozone water concentration and the TOC concentration. FIGS. 8 and 9 are schematic block diagrams showing a state where TOC is eluted into the apparatus by ozone treatment, and the same parts as those of the above-mentioned test apparatus are denoted by the same reference numerals. The apparatus used for the test was a test apparatus 120 (Pureculaser (registered trademark) ZPVS3U11), an ozone generator 125 (Ottotec, Inc.; ozone generation apparatus OZS-EP3-20), and an ozone water concentration meter 110 (Okitotoc, Inc.; ozone water concentration meter OZM-7000 LN). In the figure, reference numeral 111 denotes a sensor BOX, which measures PH, ORP, water temperature, and conductivity. Further, 112 denotes a flowmeter, and 118 denotes drain water. Further, 121 is a circulation pump and is incorporated in the testing apparatus 120. Further, 123 is a compressor (air compressor), 124 is a flow meter, and 128 is a flow rate adjusting valve. Further, 130 is a test water tank, and 135 is a valve.

The test method is as follows: as a water flow test for the FRP tank 153, the concentration of the ozone water introduced into the test apparatus 140 was changed to 3 types, and the test apparatus 140 was operated for 30 minutes with respect to ion-exchanged water (pure water) and adjusted to a predetermined concentration. The water transfer pump 131 was operated for the ozone water adjusted to 3 kinds of ozone water concentrations (ozone generation amount of 0.5 g/hr, 1.0 g/hr, 2.0 g/hr) by the ozone generator 125 and the injector 126, and ozone water was supplied to the FRP tank 153 for 8 hours. The FRP tank 153 used in this test was a container (not containing ion exchange resin) containing ion exchange resin (organic cylindrical water purifier AMBERLITE MB2 capacity 5L).

The test conditions were as follows.

[ test conditions ]

Test water ion exchange water;

the test water amount is 40L;

circulation flow rate 20L/min (1 cycle 120 sec);

the ozone generation amount is 0.5 g/h;

1.0 g/hour;

2.0 g/hr.

As a result of the experiment performed by the present inventors, as shown in fig. 10, it was confirmed that: the TOC amount eluted from the resin member in contact with ozone water increases linearly in proportion to the concentration of ozone water corresponding to the ozone generation amount and the contact time of ozone water with the resin member. When the results of this experiment are collated for each contact time as shown in fig. 11, the relationship between the ozone water concentration (mg/L) and the TOC concentration (mg/L) eluted can be collated for each contact time.

In fig. 11, since the relationship between the concentration of ozone water (mg/L) and the concentration of TOC eluted (mg/L) when the contact time of ozone water and the resin member is 1 hour is approximately linear, the relationship between the concentration of ozone water and the concentration of TOC eluted (mg/L) per unit time can be approximated by the following equation when the concentration of ozone water is x (mg/L) and the concentration of TOC eluted is y (mg/L).

(formula 1)

y=0.0036x＋0.070・・・(1)

In order to examine the change in the ozone supply time and the ozone water concentration, 3 ozone supply amounts of 0.5 (g/hour), 1.0 (g/hour), and 2.0 (g/hour) were set, and the change in the ozone supply time (minute) and the ozone water concentration (mg/L) per ozone supply amount was experimentally measured. The change in the ozone water concentration (mg/L) per ozone supply amount with respect to the ozone supply time (min) was measured, and based on the measurement results, the relationship between the ozone generation time t (min) and the ozone water concentration x (mg/L) was approximated 3 times, and the obtained curve was shown in fig. 12.

From the slope of the tangent line at the time of rise of the 3-time approximation curve shown in fig. 12, the rate of rise of the ozone water concentration per ozone supply amount can be obtained. The ozone water concentration increase rate in the case of the ozone supply amount other than the 3 types may be determined by linear interpolation from the ozone water concentration increase rate per unit time of the 3 types, or may be determined by actually measuring the ozone supply amount while changing the ozone supply amount more finely. As shown in the figure, the rate of increase in the ozone water concentration can be linearly approximated with high accuracy until the ozone supply time is about 10 minutes. In addition, it was also confirmed that: regardless of the amount of ozone supplied, there is an upper limit to the increase in the ozone water concentration even if the supply of ozone is continued.

In addition to the above, experiments were also conducted to confirm the change in the ozone water concentration in the case of repeated and intermittent operation of ozone supply/stop. In the experiment, the ozone supply amount was set to 2.0 (g/hour), and the change in the ozone water concentration was measured when 1 minute of ozone supply and 9 minutes of ozone stop were repeated, when 5 minutes of ozone supply and 5 minutes of ozone stop were repeated, or when 30 minutes of ozone stop was performed after 30 minutes of ozone supply.

As shown in fig. 13, in each case, the concentration of ozone water immediately after the start of supply of ozone increased approximately linearly, and the concentration of ozone water decreased exponentially after the stop of ozone. This reduction is believed to be due to the self-decomposition of ozone. When the state of decrease in the ozone water concentration is carefully observed, the ozone water concentration decreases with a half-life of about 5 minutes regardless of the combination of the ozone supply time and the stop time. In addition, the ozone concentration almost became 0 about 30 minutes after the ozone was stopped.

By creating an arithmetic expression based on the findings obtained by the above experiment and storing the arithmetic expression in the storage unit 16b, the ozone water concentration increase rate of the water to be washed is determined from the ozone supply amount, and the ozone water concentration of the water to be treated can be determined from the ozone water concentration increase rate and the ozone supply time. Further, the state of decrease in the ozone water concentration after the supply of ozone is stopped can be determined. Then, the TOC concentration of the water to be treated can be determined from the determined ozone water concentration of the water to be treated.

In fig. 1, a TOC concentration measuring device 21 measures the TOC concentration of the water to be treated flowing through the circulation flow path 20. Since it is necessary to control the TOC concentration of the washing water to be less than or equal to a predetermined concentration for the purpose of treatment by the washing water treatment device 12, and particularly in pure water, the TOC concentration needs to be controlled to be less than or equal to 1.0mg/L (or less than or equal to a predetermined value), the control device 16 monitors the treatment status and provides TOC concentration measuring means 21 for determining whether the treatment status is satisfactory or not.

The TOC concentration adjusting device 22 is provided with an electrically operated valve, an electrically operated pump, and a flow meter, which are not shown. The electric valve is controlled by the control unit 16a to discharge a predetermined amount of water to be treated. The electric pump is controlled by the controller 16a, and a predetermined amount of pure water is supplied to the circulation flow path 20 by a pure water producing apparatus not shown.

The reason why the wastewater to be treated and the pure water are supplied by the TOC concentration adjusting device 22 in this manner is that: since it is difficult to remove TOC eluted into the water to be treated at a time, the TOC dissolved in the water to be treated is discharged by discharging the water to be treated containing TOC, so that the TOC amount existing in the washing treatment unit 11 and the washing treatment device 12 is reduced, and pure water equivalent to the discharged water to be treated is supplied again, whereby the TOC concentration of the washing water existing in the washing treatment unit 11 and the washing treatment device 12 is reduced and is suppressed to a predetermined value or less.

In addition, in order to reliably perform the washing process of the member to be treated in the washing treatment unit 11, a predetermined amount of washing water needs to be present inside the washing treatment unit 11 and the washing treatment apparatus 12, but since the washing water evaporates from the washing tank or the washing water adhering to the member to be treated is carried out from the washing tank during the washing process of the member to be treated, the washing water naturally decreases with the washing process, and therefore, it is necessary to replenish the naturally reduced amount of pure water. This replenishment also helps to reduce TOC concentration.

Next, the operation of the washing water treatment apparatus of the present invention will be described. As shown in FIG. 1, in the washing water treatment apparatus 12, pure water used for the washing treatment of the member to be treated in the washing treatment section 11 flows in as water to be treated through the supply passage 23 and is stored in the washing water storage section 13 (capacity: 200L to 300L). The water to be washed stored in the washing water storage unit 13 is sent to the bacteria elimination and purification unit 14 through the inflow passage 17 by a pump not shown.

The water to be treated sent to the sterilization purification unit 14 is mixed with a predetermined amount of ozone (and dissolved oxygen) from an injector provided in an ozone supply unit, and the ozone in the form of fine bubbles is dissolved in the water to be treated in the form of bubbles to prepare a mixed liquid (ozone water). In this case, when the concentration of the ozone water in the water to be treated becomes high, the life of the filter or the ion exchange resin 27 of the filter device 26 of the filtering mechanism unit 15 at the subsequent stage may be shortened, and the TOC amount eluted from the resin filter case housing the hollow fiber membrane filter or the resin tank housing the ion exchange resin may increase, and therefore, it is necessary to comprehensively determine the capacity of the washing water housing 13, the water supply amount of the water to be treated, and the lower limit value and the upper limit value of the concentration of the ozone water for performing the effective sterilization washing treatment and to determine the ozone water supply amount.

Most of the bacteria in the water to be treated are sterilized by the sterilizing effect of the supplied ozone, and most of the organic matter of the corpse including the sterilized bacteria are decomposed.

When the water to be treated containing ozone flows into the ultraviolet ray/photocatalyst unit located at the subsequent stage of the ozone supply unit, the water to be treated containing ozone passes through the ultraviolet ray light source and the photocatalyst, and the water to be treated into which ozone is dissolved is irradiated with ultraviolet rays, thereby generating radicals (which are chemical species having unpaired electrons and are strongly activated) called OH (hydroxyl radicals or OH radicals).

Since this OH group is strongly activated, it is possible to basically sterilize bacteria remaining in the water to be treated without being sterilized when the ozone supply unit performs the ozone treatment, and to basically decompose organic substances remaining in the water to be treated without being decomposed. In addition, since OH radicals disappear in a very short time, the filter device 26 or the ion exchange resin 27 is not damaged. OH radicals are generated by the action of ozone and ultraviolet irradiation, and bacteria and organic substances remaining in the washing water containing section 13 are surely sterilized and purified, and the life of the filter device 26 and the ion exchange resin 27 is prolonged without damaging them.

Further, OH radicals can be generated more efficiently by the ultraviolet irradiation and the action of the photocatalyst, and bacteria and organic substances remaining in the washing water storage section 13 can be surely sterilized and purified by combining with ozone of a low concentration, that is, by organically combining with the ozone, and the life can be prolonged without damaging the filter device 26 or the ion exchange resin 27.

The water to be treated, which has been subjected to the sterilization and purification treatment in the ultraviolet ray/photocatalyst unit, is returned to the washing water storage unit 13 through the outflow passage 18.

In this way, since the water to be washed stored in the washing water storage unit 13 is sterilized while circulating between the washing water storage unit 13 and the sterilizing and purifying unit 14, ozone remaining in the water to be treated returned to the washing water storage unit 13 exerts a sterilizing effect even in the washing water storage unit 13, suppresses the growth of bacteria, and suppresses the generation of a biofilm on the wall surface of the washing water storage unit 13.

Further, since the water to be treated is returned to the washing water storage 13 instead of being immediately sent to the filter mechanism unit 15 after the sterilization and purification in the sterilization and purification unit 14 and then mixed with the water to be treated stored in the washing water storage 13, the ozone water concentration of the water to be treated stored in the washing water storage 13 as a whole is diluted, and the ozone is decomposed during the storage in the washing water storage 13, so that the ozone water concentration of the water to be treated sent to the filter mechanism unit 15 is lowered.

On the other hand, in order to prevent bacteria from proliferating in washing treatment unit 11, the washing water returned from washing water treatment apparatus 12 to washing treatment unit 11 contains ozone, and after being returned to washing treatment unit 11, it is necessary to maintain a certain level of ozone water concentration even if the ozone water is mixed with the washing water stored in washing treatment unit 11. According to the experimental results of the present inventors, the sterilizing power of ozone is extremely strong, and if the ozone water concentration is about 0.05 (mg/L), almost all bacteria can be sterilized within a few minutes, so if the amount of treated water is about 40 (L), the amount of ozone supplied from the ozone supply unit of the sterilization/purification unit 14 is preferably about 0.05 (g/hr) in consideration of dilution or decomposition in the washing water storage unit 13.

In this way, in the washing water storage 13, the water to be treated having a somewhat reduced ozone water concentration is fed to the filter mechanism 15 through the filter flow path 19, and as described above, the ozone supply amount to the water to be treated from the ozone supply unit of the sterilization purification unit 14 is small, and the ozone itself is decomposed, and the ozone water concentration of the water to be treated is also reduced, so that the filter or the ion exchange resin 27 of the filter device 26 of the filter mechanism 15 is not damaged by the residual ozone in the water to be treated, and the life is not shortened. In the present embodiment, the low-concentration ozone is used to perform sterilization in the filter mechanism unit 15, and the TOC elution is suppressed to the minimum and the water to be treated having an ozone concentration sufficient for sterilization is managed.

Further, since the bacteria remaining in the water to be treated are basically sterilized in the bacteria removing and purifying unit 14 and the water to be treated, in which the organic substances remaining in the water to be treated are basically decomposed, is fed to the filter mechanism unit 15 through the filter flow path 19, clogging of the filter mechanism unit and deterioration of the function of the ion exchange resin due to the bacteria and the organic substances are less likely to occur, and the life of the filter and the function of the ion exchange resin can be prolonged.

The water to be treated, which is transported from the washing water storage unit 13 to the filter mechanism unit 15, is subjected to a filtration treatment in the filter device 26 to remove bacteria and organic substances remaining in the water to be treated, and then salt components in the water to be treated, which cannot be removed by the ozone treatment or the filtration treatment, are removed by the ion exchange resin 27, and thereafter returned to the washing treatment unit 11 through the circulation flow path 20.

However, in the washing water treatment apparatus 12 of the present invention, since the water to be treated returned to the washing treatment unit 11 after the sterilization and purification treatment contains ozone at a low concentration, it is possible to prevent an increase in bacteria in the washing treatment unit 11. Therefore, TOC is eluted from the impeller made of resin, the filter case made of resin of the filter device 26, and the storage tank made of resin of the ion exchange resin 27 in the sterilization purification unit 14 in the water to be treated which still contains ozone at a low concentration.

Therefore, if the water to be treated after the sterilization and purification treatment is directly returned to the washing treatment unit 11, the TOC concentration of the washing water in the washing treatment unit 11 increases in sequence, and eventually the water quality requirement as pure water cannot be satisfied. In order to suppress the increase of the TOC concentration of the washing water in the washing processing unit 11, in the washing water treatment apparatus of the present invention, a TOC concentration adjusting means 22 is provided in the circulation flow path 20 of the water to be treated, and the supply of pure water is performed while discharging the water to be treated in accordance with the ozone water concentration and the TOC concentration of the water to be treated before returning the water to the washing processing unit 11, thereby suppressing the TCO concentration of the washing water used in the washing processing unit 11 to a predetermined value or less. In the present embodiment, since the TOC concentration adjusting device 22 is provided in the circulation flow path 20 immediately before the washing processing unit 11, it is suitable to adjust the TOC concentration with high accuracy.

As described above, in the washing water treatment apparatus 12, the pure water used for washing the member to be treated in the washing treatment unit 11 is stored in the washing water storage unit 13 as the water to be treated, the bacteria elimination purification treatment is continuously performed while circulating the water to be treated between the washing water storage unit 13 and the bacteria elimination purification unit 14, and the stored water to be treated is sent to the filter mechanism unit 15 to be filtered, and then the water to be treated is supplied with the pure water or the drain of the water to be treated and the pure water in accordance with the ozone water concentration and the TOC concentration of the water to be treated by the TOC concentration adjusting device 22, and then returned to the washing treatment unit 11, whereby the TOC concentration of the washing water used in the washing treatment unit 11 is suppressed to a predetermined value or less.

The water to be treated is circulated between the washing water storage 13 and the sterilizing and purifying unit 14 while performing the sterilizing and purifying treatment, and the water to be treated after the sterilizing and purifying treatment in which ozone is dissolved is returned to the washing water storage 13, so that organic substances and bacteria contained in the water to be treated in the washing water storage 13 can be gradually reduced, and the proliferation of bacteria in the washing water storage 13 can be suppressed.

As a result, organic substances and bacteria contained in the water to be treated, which is transported from the washing water storage unit 13 to the filter mechanism unit 15, are significantly reduced as compared with the case where the bacteria removal and purification unit 14 does not perform the circulation treatment, and therefore, clogging of the filter device 26 and deterioration of the function of the ion exchange resin 27 due to the bacteria and organic substances subjected to the filtration treatment can be suppressed.

In addition, the water to be treated, which is transferred from the washing water storage unit 13 to the filter mechanism unit 15, may contain low-concentration ozone, which is low-concentration ozone to such an extent that the function of the filter or the like is not affected, and the filter or the ion exchange resin 27 of the filter device 26 of the filter mechanism unit 15 is not damaged, so that the growth of bacteria can be suppressed in the filter mechanism unit 15, the circulation flow path 20, and the washing treatment unit 11.

In the filtration mechanism section 15, the filter (preferably, a hollow fiber membrane of UF membrane) of the filtration device 26 removes fine particles, bacteria, and organic polymers, and the ion exchange resin 27 removes salts such as calcium, sodium, chloride, and sulfuric acid in the water to be treated, which cannot be removed by the ozone treatment or the filtration treatment.

Further, since the water to be treated still contains ozone of a low concentration, the increase in TOC concentration due to TOC eluted from the impeller, filter housing, tank, or the like made of resin allows the TOC concentration of the washing water to be suppressed to a predetermined value or less by supplying pure water to the water to be treated or supplying pure water to the water to be treated by the TOC concentration adjusting means 22 based on the ozone water concentration and TOC concentration of the water to be treated, or by discharging the water to be treated and supplying pure water, and the water to be treated can be reused as pure water satisfying the water quality requirement.

In the washing water treatment apparatus of the present invention, since the water to be treated is subjected to the sterilization purification treatment and the filtration treatment as described above and the TOC concentration is suppressed to a predetermined concentration or less, even if the water is reused as washing water (pure water) in the washing treatment unit, the quality of the product is not adversely affected, and the pure water used in the washing treatment unit can be saved for a long period of time to perform stable washing treatment, so that the washing cost can be suppressed.

Next, a washing water treatment method using the washing water treatment apparatus of the present invention will be described. First, a case where a predetermined amount of ozone is continuously supplied from the ozone supply unit of the sterilization/purification unit will be described. In this method of treating washing water in which ozone is continuously supplied, a total supply amount of ozone is increased by continuously supplying a predetermined amount of ozone, and therefore, for example, a large member to be treated can be washed and treated, and the method can be applied to a case where a sterilization and purification treatment is effectively performed on water to be treated having a large amount of bacteria or organic substances mixed therein.

When the total amount of washing water (L) to be treated (for example, the capacity of a washing water tank provided in a washing treatment unit), the supply amount of ozone (g/hour), and the ratio of water to be treated to the total amount of washing water are inputted, the total amount of washing water (mg) and the drain amount of washing water (L) (≈ pure water (L) to be supplied), the total amount of washing water (mg) after pure water supply, and the total TOC concentration (mg/L) of washing water after pure water supply are sequentially calculated from the storage unit 16b based on the TOC increase rate per unit time, and the change in TOC concentration (mg/L) of the total washing water after pure water supply is determined.

In this case, the total amount of washing water to be treated (L) and the amount of ozone supplied (g/hour) are fixed values, but the ratio of the water to be treated to be drained to the total amount of washing water can be arbitrarily changed, and therefore, if this value is changed to determine the change in the TOC concentration (mg/L) of the total washing water after pure water supply, the ratio of the water to be treated to be drained to the total amount of washing water, which does not exceed 1.0 (mg/L) which is the standard of pure water, can be determined.

Fig. 14 shows simulation results of determining the change in TOC concentration (mg/L) of the total washing water, assuming that the total washing water amount is 40 (L) and the ozone supply amount is 0.5 (g/h), and the drain amount of the water to be treated and the supply amount of pure water are 3 (L/h). As shown in the figure, the TOC concentration of the total washing water does not exceed 1.0 (mg/L), which is the water quality requirement of pure water, even after the treatment time has elapsed.

As shown in fig. 12, since the concentration of the ozonized water after the supply of ozone does not increase to a certain concentration or more, the relationship between the supply amount of ozone and the ozonized water concentration of the water to be treated was determined by using the above-mentioned equation 1, and determining the rate of increase of ozone with respect to the ozonized water concentration, using 0.32 (mg/L) in which the ozonized water concentration is stable, as the ozonized water concentration when 0.5 (g/hour) of ozone is supplied, and was used for the simulation.

Therefore, in the case of performing the method of treating the washing water in which the predetermined amount of ozone is continuously supplied by using the washing water treatment apparatus of the present invention, if pure water is supplied at a rate of 3 (L/hr) while discharging the water to be treated at 3 (L/hr) by the TOC concentration adjusting device 22 while continuously supplying ozone at 0.5 (g/hr) from the ozone supply portion of the sterilization purification unit 14, the TOC concentration of the washing water used in the washing treatment portion 11 can be suppressed to 1.0 (mg/L) or less.

Next, a case will be described in which pure water is supplied from the TOC concentration adjusting device in an amount corresponding to the amount of washing water that is naturally reduced when the member to be washed is washed in the washing treatment unit, and a predetermined amount of ozone is intermittently supplied from the ozone supply unit. In this method for treating washing water, the amount of pure water supplied is equivalent to the amount naturally reduced during the washing treatment of the member to be treated, so that the amount of expensive pure water used can be minimized, and the washing cost can be reduced. Further, since a predetermined amount of ozone is supplied by intermittent supply in which supply for a certain period of time and stop for a certain period of time are repeated, the total supply amount of ozone is not large, and is applicable to, for example: washing a small-sized member to be treated, and sterilizing and purifying the water to be treated, which does not contain much bacteria or organic substances, at low cost. The washing water that naturally decreases during the washing process means washing water that evaporates from the washing tub and washing water that adheres to and is carried away from the material to be treated during the washing of the material to be treated.

In this method of treating washing water, when a total amount of washing water (L) to be treated (for example, the capacity of a washing water tank provided in a washing treatment unit), an amount of ozone supplied (g/hour), a ratio of pure water to be supplied to the total amount of washing water, an ON time (minute) for supplying ozone, and an OFF time (minute) for stopping the supply are inputted, an arithmetic expression is called from the memory device 16b to determine a change in TOC concentration (mg/L) of the total washing water, and the change in concentration of ozone water to be treated can be determined from a change in concentration of ozone water with respect to a treatment time and a change in concentration of ozone water with respect to the treatment time based ON an ozone water concentration increase coefficient corresponding to the amount of ozone supply and a tendency that the concentration of ozone water decreases with a half-life of 5 minutes when the supply of ozone is stopped.

At this time, the total amount of washing water to be treated (L), the amount of ozone supplied (g/hour), and the amount of pure water to be supplied (L/minute) to compensate for the naturally decreased amount of washing water are fixed values, but the combination of the ON time (minute) during which ozone is supplied and the OFF time (minute) during which ozone is not supplied can be arbitrarily changed, and therefore, if the ON time and the OFF time are changed to obtain the change in TOC concentration (mg/L) of the total washing water, the combination of the ON time during which ozone is supplied and the OFF time during which supply is stopped, in which TOC concentration (mg/L) of the total washing water after supply of pure water does not exceed 1.0 (mg/L) which is a standard for pure water, can be obtained.

Fig. 15 is a result of simulation of changes in the concentration of ozone water when the ON time for supplying ozone is set to 7 (minutes) and the OFF time for stopping ozone supply is set to 3 (minutes) in the case where the total amount of washing water is 40 (L), the amount of ozone supplied is 0.5 (g/hour), and the amount of pure water supplied is 2.7 (L/minute), and fig. 16 is a result of simulation of changes in the TOC concentration of the total washing water at this time in the case where pure water is supplied and in the case where pure water is not supplied. As shown in fig. 16, when pure water corresponding to the natural amount of reduction in the washing water is supplied, the TOC concentration of the total washing water is much lower than the TOC concentration 1.0 (mg/L) required as the water quality of pure water even after the elapse of the treatment time.

Therefore, in the case of performing the method of treating the washing water in which the predetermined amount of ozone is intermittently supplied by the washing water treatment apparatus of the present invention, if pure water corresponding to the natural amount of reduction of the washing water is supplied while the ON time for supplying ozone and the OFF time for stopping the supply of ozone are appropriately set while the ozone supply unit of the sterilization purification unit 14 continuously supplies 0.5 (g/hour) of ozone, the TOC concentration of the washing water used in the washing treatment unit 11 can be suppressed to 1.0 (mg/L) or less.

Next, a case where the washing water treatment apparatus of the present invention is applied to a plating process will be described. The same reference numerals are used for the same functional portions as those described above, and the description thereof will be omitted. As shown in fig. 17, in the plating step, the bacteria elimination and purification unit 14 is connected to the final washing water tank 35 of 4 washing water tanks provided in addition to the plating tank 31.

In this plating step, the washing water tank 32 is provided for collecting the plating liquid, and the washing water tanks 33, 34, and 35 are provided for washing the object to be treated after the plating treatment.

Washing water tank 33 and washing water tank 34 are connected to each other, and are configured as follows: the pure water supplied to the washing water tank 34 overflows the partition between the washing water tank 33 and the washing water tank 34, flows into the washing water tank 33, and is discharged from a drain port 36 provided in the washing water tank 33.

Pure water for washing is stored in the washing water tank 35, the washing water tank 35 and the sterilizing and purifying unit 14 are connected to each other by the inflow passage 17 and the outflow passage 18 so as to be circulated, and the washing water tank 35 and the filter mechanism unit 15 are connected to each other by the filter passage 19. The filter mechanism unit 15 and the washing water tank 35 are connected by a circulation flow path 20, and a TOC concentration measuring device 21 and a TOC concentration adjusting device 22 are provided in the circulation flow path 20.

The TOC concentration measuring device may measure the TOC concentration at any time using an on-line TOC meter, or may measure the TOC concentration by collecting wash water from the circulation channel.

That is, in the plating step shown in fig. 17, the washing water tank 35 is both the washing processing unit 11 and the washing water storage unit 13. Therefore, the pure water used for washing the object to be treated in the washing water tank 35 as the washing treatment unit 11 is sent from the washing water tank 35 to the filter mechanism unit 15 to be subjected to the filtering treatment while being circulated between the washing water tank 35 and the bacteria elimination and purification unit 14, and is then returned to the washing water tank 35 as the washing treatment unit.

In this way, the washing water stored in the washing water tank 35 as the washing water storage unit 13 is circulated between the washing water tank 35 and the sterilization and purification unit 14 while performing sterilization and purification treatment, and is also circulated between the washing water tank 35 and the filter mechanism unit 15 while performing filtration treatment, and the supply of pure water to the water to be treated or the discharge of the water to be treated and the supply of pure water are performed by the TOC concentration adjusting device 22 in accordance with the ozone water concentration and the TOC concentration of the water to be treated, so that the TOC concentration is suppressed, and the washing water in the washing water tank 35 is maintained to be reusable as pure water satisfying the water quality requirement.

Next, a case where the washing water treatment apparatus of the present invention is applied to a semiconductor manufacturing apparatus will be described. The same reference numerals are used for the same functional portions as those described above, and the description thereof will be omitted. Fig. 18 schematically shows a single wafer type cleaning apparatus 41, which shows a state in which pure water is blown from a nozzle 44 onto a wafer 43 placed on a turntable 42 and rotated to clean the surface of the wafer 43. Pure water for washing is stored as water to be treated in a washing water collection tank 45 provided below the single wafer type washing apparatus 41.

Therefore, in the single-wafer type washing apparatus 41 shown in fig. 18, the nozzle 44 and the turn table 42 are the washing processing unit 11, and the washing water collection tank 45 provided below the single-wafer type washing apparatus 41 serves as the washing water storage unit 13.

In the single-wafer type washing apparatus 41, similarly to the plating process shown in fig. 17, the washing water stored in the washing water recovery tank 45 of the washing water storage unit 13 is circulated between the washing water recovery tank 45 and the sterilization and purification unit 14 while performing the sterilization and purification process, and the washing water is circulated between the washing water recovery tank 45 and the filter mechanism unit 15 while performing the filtration process, and then the supply of pure water to the water to be treated or the discharge of the water to be treated and the supply of pure water are performed by the TOC concentration adjusting means 22 in accordance with the ozone water concentration and the TOC concentration of the water to be treated, so that the TOC concentration is suppressed, whereby the washing water in the washing water recovery tank 45 is maintained to be reused as pure water satisfying the water quality requirement.

In the single wafer type washing apparatus 41 shown in fig. 18, the water to be treated is pure water, and the water to be treated collected in the washing water collection tank 45 is treated so as to be reusable, but if the washing water discharged from the nozzle 44 is treated so as to be reusable, the washing water collection tank 45 does not necessarily need to be provided separately in the single wafer type washing apparatus 41. Therefore, the sterilizing and purifying unit 14, the filter mechanism unit 15, the TOC measuring device 21, and the TOC concentration adjusting device 22 can be provided at any position of the long flow path before the water to be treated reaches the nozzle 44, and the single-chip washing apparatus can be provided in which the water to be treated is treated in the flow path so as to be reusable. This is suitable for washing highly integrated wafer 43 using ultrapure water as the water to be treated.

In this case, when the single wafer type cleaning apparatus is operated (in the cleaning step), ultrapure water for cleaning is intermittently supplied to the single wafer type cleaning apparatus at the time of cleaning the wafer 43, and the ultrapure water flows through a long flow path to the nozzle 44 in a state of containing an organic substance. When the washing water collection tank is a long flow path to the nozzle 44, this is substantially the same as the case where the washing water containing organic matter is stored in the washing water collection tank 45 described above.

In addition, the ultrapure water taken in from the outside of the single-wafer cleaning apparatus for treating the water to be treated in the flow path to be reusable may contain a trace amount of organic substances.

These organic substances may be attached to the inside of a pipe such as a PFA pipe forming a flow path and contained in ultrapure water used as washing water.

Therefore, in the single wafer type cleaning apparatus, not only the cleaning water after cleaning the wafer 43 but also the flow path such as the inside of the pipe up to the nozzle 44 needs to be cleaned to remove organic substances attached to the inside. In this case, if the pipe is made of resin such as PFA, ozone resistance is obtained, but there is a possibility that a very small amount of TOC is generated or there is a possibility that the TOC component on the pipe surface is easily eluted, and therefore, it is necessary to consider the suppression of TOC concentration in the case of sterilization with ozone, as in the case described above.

Therefore, the water to be treated (ultrapure water) held in the flow path is purified by the disinfecting and purifying unit 14 provided in the flow path, and the water to be treated in the single-wafer type washing apparatus is passed through the filter mechanism unit 15, the TOC concentration measuring device 21, and the TOC concentration adjusting device 22 to be disinfected and purified. In this way, when such a single-chip washing apparatus is newly introduced into the washing step or used for a long period of time, the treated water from which organic substances have been removed can be supplied from the nozzle 44 while suppressing the TOC concentration.

At this time, the supplied water to be treated (ultrapure water) is added with ozone by the sterilization purification unit 14, and then flows through the long flow path. In the process of adding ozone, the ozone itself is decomposed, and some of the ozone generates OH radicals, which promote the decomposition of the eluted TOC components and organic substances adhering to the inside of the pipe. Therefore, the amount of ozone generated from the sterilization and purification unit 14 is adjusted in advance in accordance with the flow rate or flow rate of the water to be treated, and ozone, which is decomposed by itself and whose content is more likely to decrease in the vicinity of the secondary side of the long flow path, can be sufficiently left. Thus, the ozone water maintaining the residual ozone concentration can be made to flow through the entire long flow path, and the organic matter in the entire piping can be decomposed.

In the case of the single wafer type cleaning apparatus in which the entire flow path is used as the cleaning water collection tank as described above, since the degree of contamination of the flow path by the water to be treated is substantially constant at the time of cleaning (non-operation) of the non-maintained wafer 43 or at the time of newly installing the single wafer type cleaning apparatus, the filtering mechanism unit 15 or the TOC concentration measuring means 21 is removed, and the ultrapure water is replenished by the TOC concentration adjusting means 22 and mixed with the ultrapure water accumulated in the long flow path, and in this state, the concentration of the ozonated water can be adjusted by the sterilization/purification unit 14 to clean the inside of the flow path. Accordingly, even when the single wafer cleaning apparatus is maintained or newly installed, the organic substances in the flow path can be decomposed other than when the wafer 43 is cleaned.

In other words, the present invention may be said to be a method for cleaning a semiconductor wafer cleaning apparatus using ultrapure water, wherein ultrapure water is supplied by a TOC concentration adjusting means, the ultrapure water is sterilized and purified by a sterilizing and purifying unit, an ozone generation amount is adjusted in accordance with a flow rate and a flow rate of water to be treated which is supplied to the inside of the apparatus in advance, so that ozone remains in a flow path pipe reaching a tip nozzle, and decomposition of organic substances in the flow path pipe and an extremely small amount of TOC generated in the flow path pipe are suppressed by the ultrapure water supply and the adjustment of ozone water concentration.

In particular, when the apparatus is not operating, the ultrapure water retained in the pipe and the ultrapure water supplied can be mixed and sterilized.

In this case, when ultrapure water is supplied from the outside through the TOC concentration adjusting means and the water to be treated is caused to flow into the flow path to dilute the TOC concentration, for example, the following configuration can be adopted: a drain pipe, not shown, is provided at an appropriate position of the flow path, and water is drained to the outside of the single-chip washing apparatus through the drain pipe. In this case, since the treatment is a non-circulating type treatment in which the water to be treated is not circulated, the TOC concentration can be efficiently controlled to 0.01mg/L or less which is an index of ultrapure water when the TOC concentration is adjusted.

The sterilizing and purifying unit 14 can be installed inside the single-chip type washing apparatus, and in this case, since it is installed in close proximity to the flow path, OH radicals generated by ozone which is easily decomposed by itself can be efficiently introduced into the flow path, and ozone water maintaining sterilizing ability can be flowed into the entire flow path.

It is known that, in such washing, functional water for washing to which a small amount of ozone is added is used (analytical chemistry overview, volume 59, No.5, page 349 to page 356 (2010)), but in the present invention, control of the concentration of ozone water according to the flow rate/flow rate of water to be treated flowing into a pipe and control of inhibition based on a very small amount of TOC to which ozone is added or TOC components eluted into ultrapure water are performed, unlike the case where only functional water for washing is used.

Further, a case where the washing water treatment apparatus of the present invention is applied to a glass substrate manufacturing apparatus will be described. Fig. 19 schematically shows a glass substrate washing apparatus 51 of the horizontal conveyance type. The glass substrate 52 is cleaned by blowing pure water from the cleaning nozzle 54 while being conveyed by the conveying roller 53. Pure water for washing is stored as water to be treated in a washing water collection tank 55 provided below the glass substrate washing apparatus 51.

Therefore, in the glass substrate washing apparatus 51 shown in the figure, the washing nozzle 54 and the conveying roller 53 constitute the washing processing unit 11, and the washing water collection tank 55 provided below the glass substrate washing apparatus 51 serves as the washing water storage unit 13.

In the glass substrate washing apparatus 51, similarly to the plating process step of fig. 17 or the single wafer type washing apparatus 41 of fig. 18, the washing water stored in the washing water recovery tank 55 as the washing water storage unit 13 is circulated between the washing water recovery tank 55 and the sterilization and purification unit 14 while performing the sterilization and purification treatment, and the filtration treatment is performed while circulating between the washing water recovery tank 55 and the filter mechanism unit 15, and then, based on the ozone water concentration and the TOC concentration of the water to be treated, the supply of pure water to the water to be treated by the TOC concentration adjusting means 22 or the supply of drain water and pure water of the water to be treated is performed to suppress the TOC concentration, thereby maintaining the washing water in the washing water recovery tank 55 to be reusable as pure water satisfying the water quality requirement.

As described above, according to the washing water treatment apparatus and the washing water treatment method of the present invention, since the bacteria removing and purifying treatment and the filtering treatment are performed on the pure water used for washing the member to be washed in the washing treatment section so as to keep bacteria and organic matters at a low level and the TOC concentration is suppressed to a predetermined concentration or less, the bacteria removing and filtering treatment of the reused washing water and the so-called reverse function of eluting TOC from the casing of the filter or the like can be combined and reused as the washing water satisfying the water quality requirement as the pure water.

In addition, since the water to be treated returned to the washing treatment unit contains ozone at a low concentration, the growth of bacteria in the washing treatment unit or the washing water treatment apparatus can be prevented, the interval between cleaning of the washing treatment unit and exchange of pure water can be extended, and the life of the filter or ion exchange resin of the washing water treatment apparatus can be extended. This makes it possible to increase the operating rate of a manufacturing apparatus using the washing water treatment apparatus and the washing water treatment method of the present invention, thereby reducing the manufacturing cost.

In the present embodiment, the calculation formula obtained by converting the findings obtained by the above experiment into data or the data table obtained by converting the findings into data are used because the TOC concentration is relatively low even when the resin filter case or the resin tank is used, that is, when the expected conditions under which the TOC is most eluted, for example, when the filter case is made of stainless steel or the tank is made of stainless steel.

The relationship between the concentration of ozone water and the TOC concentration used in the arithmetic expression or the data table can be obtained by experiments using a washing water treatment apparatus used in an actual field for washing a semiconductor wafer substrate, a liquid crystal glass substrate, a plated electronic component, or the like (so-called field adjustment).

The TOC concentration adjusting device 22 may be provided at any position as long as it is located in the circulation flow path 20, but is preferably provided at a position at the rear stage of the filter mechanism unit 15 because the TOC concentration of the washing water before the washing process is the lowest.

In the present embodiment, the description has been given mainly of the washing water treatment apparatus and the method thereof in which the water to be treated is pure water, but the present invention is applicable even to water to be treated which is ultrapure water. In this case, if the reference value of the TOC concentration adjusting means is set to, for example, 0.01 (mg/L), and the wastewater of the water to be treated and the supply of pure water or ultrapure water are controlled so that the TOC concentration is suppressed to the reference value or less in accordance with the ozone water concentration used in the washing water treatment apparatus, it is possible to provide washing water satisfying the water quality without wastefully using pure water or ultrapure water.

In particular, in a washing water treatment apparatus for treating ultrapure water, although the filter mechanism unit 15 is in a state of being ozone-removed, if ozone water having a low concentration is used, the filter or ion exchange resin is resistant to ozone, and it is a finding of the present test that if the ozone water concentration is high enough to perform sterilization, as described in patent document 2, even in an ultrapure water production apparatus, sterilization can be performed.

Description of the symbols

11: a washing treatment section;

12: a washing water treatment device;

13: a washing water storage part;

14: a sterilizing purification unit (sterilizing/water purifying treatment device);

15: a filter mechanism section;

16: a control device;

17: an inflow channel;

18: an outflow channel;

19: a filtration flow path;

20: a circulation flow path;

22: a TOC concentration adjusting device;

26: a filtration device;

27: ion exchange resins.