Treatment apparatus for washing water for semiconductor elements, liquid crystal glass or electronic components and method for treating washing water for semiconductor elements, liquid crystal glass or electronic components

Abstract

Provided are a washing water treatment device, a disinfection and water treatment device, and a washing water treatment method, that are capable of sterilizing bacteria in pure water to be reused and breaking down organic matter effectively, suppressing the TOC concentration of the pure water to no more than a prescribed value, and being operated for a long periods using a simple structure.　The washing water treatment device 12 comprises a control unit 16 comprising: a storage unit 16b that stores an arithmetic expression capable of finding a treatment water discharge volume and pure water supply volume in accordance with the treatment water ozone concentration and TOC concentration; and a control unit 16a that controls an ozone supply unit and a TOC concentration adjustment means 22. The washing water treatment device 12, the disinfection and water treatment device, and the cleaning method are characterized by: supplying pure water to the treatment water or draining treatment water and supplying pure water, using the TOC concentration adjustment means 22 and in accordance with the results found from the arithmetic formula; and suppressing the TOC concentration for the washing water used by a cleaning unit 11 to no more than a prescribed value.

Description

[Technical field]

[0001] The present invention purifies and processes pure water used in the cleaning process of semiconductor manufacturing, liquid crystal manufacturing, and plating of electronic parts so that it can be reused. For semiconductor devices, liquid crystal glass, or electronic components Wash water treatment equipment For semiconductor devices, liquid crystal glass, or electronic components This relates to a method for treating wash water. [Background technology]

[0002] In the manufacturing of semiconductor elements or liquid crystal glass, or in the cleaning process in the plating of electronic components, a large amount of pure water is used to clean semiconductor wafer substrates, liquid crystal glass substrates, glass substrates, plated electronic components, etc. From the viewpoints of reducing the burden on the environment and making effective use of water resources, the pure water used for cleaning is widely recovered and reused.

[0003] In the manufacturing processes for semiconductor elements and liquid crystal glass, organic solvents are widely used for removing photoresist, etc., and the pure water used in the cleaning process for semiconductor elements and liquid crystal glass (hereinafter referred to as "cleaning water") contains foreign matter, alcohol, surfactants, and other organic matter. Therefore, when recovering this cleaning water and reusing it in the semiconductor production process, it is necessary to remove the solid particles and organic matter contained in the cleaning water.

[0004] If cleaning water containing organic matter is used in the cleaning process in the manufacture of semiconductor elements or liquid crystal glass, the organic matter adhering to the object to be cleaned can cause defects in the circuit patterns on the substrate surface, or can carbonize and cause insulation failure in the subsequent heat treatment process, resulting in deterioration of product quality and yield. Also, if cleaning water containing organic matter is used in the cleaning process in plating electronic parts, the organic matter adhering to the product can cause short circuits, resulting in deterioration of product quality and yield.

[0005] In the above-mentioned cleaning process, the cleaning water is collected and filtered to remove any solid particles and organic matter contained in the cleaning water, and then reused as pure water. However, even if the pure water initially contains almost no bacteria, bacteria originally attached to the equipment or the object being cleaned, as well as bacteria present in the air, can get into the pure water, and types of bacteria that grow even in low-nutrient conditions can grow during the collection and reuse of the cleaning water, contaminating the pure water, the pure water storage tank, the cleaning water storage tank, and the piping that circulates these tanks.

[0006] Because bacteria are also organic matter, if pure water contaminated with bacteria is used in the cleaning process in the manufacture of semiconductor elements or liquid crystal glass, or in the cleaning process in the plating process of electronic components, it can cause defects in the circuit patterns on the surface of the substrate or short circuits, resulting in deterioration of product quality and reduced yields.

[0007] Therefore, in order to keep the bacteria that inevitably exist in the pure water at as low a level as possible, it is necessary to periodically stop the operation of the manufacturing equipment, sterilize and clean the pure water tank and cleaning water tank in the cleaning equipment (hereinafter referred to as the "cleaning processing section") as well as the inside of the piping that circulates these tanks with a disinfectant such as sodium hypochlorite, wipe off the biofilm that has adhered to the walls of the water tank, thoroughly post-clean the inside of the equipment with pure water so that no disinfectant remains in the cleaning processing section, and fill the cleaning processing section with new pure water.

[0008] Pure water is expensive, so frequent replacement of the water increases the manufacturing costs of the product. In addition, the sterilization process in the cleaning processing section, which must be performed by periodically shutting down the manufacturing equipment, reduces the operating rate of the manufacturing equipment, resulting in an increase in the manufacturing costs of the product.

[0009] In addition, when the washing water used in the washing process is recovered and reused, it is usually first captured and removed using a filtration device such as a hollow fiber membrane filter or activated carbon to capture and remove relatively large organic matter in the washing water, and then the water is brought into contact with an ion exchange resin (cation exchange resin, anion exchange resin) to remove the ions in the washing water before being reused as pure water. However, if bacteria grow in the washing water, the filtration device will become clogged and the function of the ion exchange resin will deteriorate early, which will increase the frequency of replacing the filters and ion exchange resin in the filtration device, thereby increasing the manufacturing costs of the product.

[0010] It has been known for some time that injecting ozone is an effective means of sterilizing bacteria in pure water when the pure water is recycled. For example, Patent Document 1 proposes an ultrapure water production system in which an ozone injector is attached to a pipe that returns unused ultrapure water at the point of use to an ultrapure water tank in order to prevent the generation of bacteria in the ultrapure water that is recycled, and this ozone injector injects ozone into the ultrapure water to constantly sterilize the ultrapure water.

[0011] In the past, pure water and ultrapure water were defined only in terms of resistivity (conductivity), but due to increasing demands for water quality, the amount of organic matter expressed as TOC (Total Organic Carbon) has recently come to be defined as an indicator of pure water and ultrapure water, with a TOC of 1.0 mg / L or less for pure water and 0.01 mg / L or less for ultrapure water. However, when pure water containing ozone comes into contact with plastic parts such as piping, the organic materials in the plastic dissolve, increasing the TOC concentration of the pure water and causing the plastic to deteriorate.

[0012] As a technique for supplying ozone to pure water to sterilize bacteria in the water while preventing an increase in the TOC concentration of the pure water, Patent Document 2 proposes an ultrapure water production and supply system that operates continuously while continuously injecting low concentration ozone at an appropriate position in a circulation line to sterilize bacteria in the ultrapure water, and decomposes the residual ozone in the ultrapure water using a low-pressure ultraviolet ozone decomposition device installed downstream of the injection position, thereby supplying ultrapure water with extremely reduced bacteria count and TOC concentration to the point of use.

[0013] Furthermore, Patent Document 3 proposes an ozone-containing water treatment device that can reliably remove residual ozone and dissolved oxygen by combining an ultraviolet irradiation device, a degassing device, and a catalytic resin device or an activated carbon decomposition device to treat remaining ozone in water, and can efficiently remove hydrogen peroxide, a by-product of ultraviolet irradiation, and can be incorporated into the cleaning water production process in the electronics industry. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Japanese Patent Application Publication No. 2-261594 [Patent Document 2] Japanese Patent Application Publication No. 2-144195 [Patent Document 3] Japanese Patent Application Publication No. 6-254549 Summary of the Invention [Problem to be solved by the invention]

[0015] However, in the ultrapure water production and supply device of Patent Document 2, the pure water present between the low-pressure ultraviolet ozone decomposition device and the ozone injection point does not contain ozone, and in the ozone-containing water treatment device of Patent Document 3, the pure water present between the catalytic resin device and the activated carbon separation device and the ozone injection point does not contain ozone, so the possibility that bacteria attached to the object to be cleaned will grow in the use point or piping, which are de-ozone areas, has not yet been eliminated. If bacteria grow in these places, it will cause a deterioration in product quality and yield, and will impair the filtration performance and ion exchange capacity of the filtration membrane and ion exchange resin, requiring frequent replacement, and regular cleaning and disinfection of the equipment, resulting in a problem of reduced operation rate. In addition, if bacteria present in the device cause the filtration device (filter) and ion exchange resin device that make up the filtration mechanism to become slimy, the flow rate through the filtration mechanism will decrease, resulting in a decrease in filtration performance and the inability of the ion exchange resin device to function properly.

[0016] In the ultrapure water ozone sterilization method and device of Patent Document 2, in order to prevent TOC elution from the resin piping between the ozone supply unit where ultrapure water containing ozone is present and the inlet of the membrane degassing device and from the pure water tank, the pure water tank and the piping from the ozone supply unit to the inlet of the membrane degassing device are made of stainless steel with a mirror finish on the surface by electrolytic polishing or the like, which makes the device expensive and leads to increased manufacturing costs.

[0017] The present invention has been developed to solve the above problems, and its purpose is to provide a device that can effectively sterilize bacteria and decompose organic matter contained in the pure water to be reused, and can suppress the TOC concentration of the pure water to a predetermined value or less, and can operate for a long time with a simple structure. For semiconductor devices, liquid crystal glass, or electronic components Wash water treatment equipment For semiconductor devices, liquid crystal glass, or electronic components To provide a method for treating wash water. [Means for solving the problem]

[0018] In order to achieve the above object, the invention according to claim 1 comprises: Stores treated water after cleaning with pure water for semiconductor elements, liquid crystal glass, or electronic components during the manufacturing process. A washing water tank; Filter the water to be treated from the cleaning water tank A filtration mechanism part including a filter and an ion exchange resin, a water flow passage connecting the filtration mechanism part and a cleaning water tank, and a cleaning treatment device as a whole of Configured to be circulable The treated water is circulated A circulation flow path; An ozone water supply means for supplying sterilizing ozone water to the filtration mechanism through the cleaning water tank and the water flow passage, a TOC concentration measuring means provided on the circulation passage for measuring the TOC concentration in the water to be treated generated from at least the cleaning water tank or each part constituting the filtration mechanism, and a TOC concentration measuring means provided in front of the cleaning water tank in the circulation direction of the circulation passage for draining the water to be treated and supplying pure water. a TOC concentration adjusting means, and a discharge amount and a discharge amount of the water to be treated according to the TOC concentration in the water to be treated. pure water and a control means for determining the amount of the supply of the The control means is a TOC concentration in the water to be treated. Depending on the concentration, the TOC concentration is adjusted to reduce the amount of the treated water. pure water By supplying the TOC concentration of the cleaning water, the TOC concentration of the pure water is controlled to a specified value or less. The treated water is washed in the washing water tank. Controlled the availability For semiconductor devices, liquid crystal glass, or electronic components This is a washing water treatment device.

[0019] The invention according to claim 2 is In the case where the pure water cleaning is performed using ultrapure water, the treated water is sterilized with ozone, and the control means controls the TOC concentration adjustment means to drain the treated water and supply pure water so that the treated water can be used for cleaning the cleaning water tank. This is a washing water treatment device. In the invention according to claim 3, the control means controls the discharge amount and the amount of the water to be treated according to the TOC concentration in the water to be treated by using a memory unit storing an arithmetic expression or a data table. pure water Find the supply of For semiconductor devices, liquid crystal glass, or electronic components This is a cleaning water treatment device.

[0020] The invention according to claim 4 relates to a method for treating water after cleaning with pure water for semiconductor elements, liquid crystal glass or electronic parts in a manufacturing process. of the cleaning water tank for storing ozone water for sterilization; a filtration mechanism section including a filter and ion exchange resin for filtering the water to be treated in the cleaning water tank; a water flow passage connecting the rear of the filtration mechanism section to the cleaning water tank; and a TOC concentration adjustment means provided before the cleaning water tank in the water flow direction of the water flow passage. The filtration mechanism section and the cleaning water tank are connected to configure the entire cleaning water treatment device so that it can be circulated endlessly. The circulating system includes a circulating step for circulating the entire cleaning water treatment device; an ozone supplying step for supplying ozone water for sterilization to the cleaning water tank; and a TOC concentration measuring step for measuring the TOC concentration of the water to be treated flowing through the circulating step. and a control step of determining and controlling the amount of discharged water and the amount of pure water supplied in accordance with the TOC concentration in the water to be treated. The TOC concentration adjustment means is an adjustment means for discharging the water to be treated and supplying pure water to reduce the TOC concentration in the water to be treated generated at least from each part constituting the cleaning water tank or the filtration mechanism section, and the TOC concentration adjustment means controls the TOC concentration of the cleaning water to be used to a predetermined control value or less in the pure water by discharging the water to be treated and supplying pure water in accordance with the TOC concentration in the water to be treated, before the cleaning water tank, so that the cleaning water can be used for cleaning. Ta The present invention relates to a method for treating washing water for semiconductor elements, liquid crystal glass, or electronic parts.

[0021] The invention according to claim 5 is a method for sterilizing and controlling the treated water after cleaning with ultrapure water instead of pure water cleaning. Process is a method for treating washing water for semiconductor elements, liquid crystal glass, or electronic parts, in which a TOC concentration adjustment means discharges the water to be treated and supplies pure water, thereby controlling the water to be treated so that it can be used for washing a washing water tank. The invention of claim 6 is a method for treating cleaning water for semiconductor elements, liquid crystal glass, or electronic components, in which the control process uses a memory unit storing an arithmetic formula or a data table to determine the amount of water to be treated and the amount of pure water to be supplied depending on the TOC concentration in the water to be treated. Effect of the Invention

[0024] According to the invention of claim 1, after the cleaning water treatment device sterilizes bacteria contained in the water to be treated and filters out solid particles and organic matter, the TOC concentration adjustment means supplies pure water and drains the water to be treated and supplies pure water depending on the TOC concentration in the water to be treated. Therefore, the water to be treated whose TOC concentration has been suppressed to a predetermined concentration or less can be returned to the cleaning water tank (point of use). Therefore, products such as electronic components and liquid crystal glass substrates brought into the cleaning water tank can be washed with cleaning water that meets the water quality requirements, thereby preventing deterioration of product quality and improving manufacturing yield. In addition, the TOC concentration adjusting means adjusts the TOC concentration of the water to be treated according to the TOC concentration eluted from each part of the cleaning water treatment device. pure water By adjusting the supply of the cleaning water, the TOC concentration of the cleaning water used in the cleaning water tank is suppressed to a predetermined value or lower that can be used in the cleaning water tank, making it possible to reuse the water as cleaning water for, for example, semiconductor manufacturing, liquid crystal manufacturing, or electronic component manufacturing.

[0025] According to the invention of claim 2, Since the water to be treated in the wash water treatment device contains a low concentration of ozone, it is possible to suppress the proliferation of bacteria in the wash water treatment device and in the piping, which makes it difficult for bacteria to clog the filters in the filtration mechanism and reduce the function of the ion exchange resin, thereby extending their lifespan. In addition, by suppressing the proliferation of bacteria, it is possible to suppress the occurrence of biofilms and slime in the filtration mechanism, which results in the extension of the interval between washing and cleaning the wash water treatment device.

[0026] According to the invention of claim 3,The initially set arithmetic formula is set using materials (resins) from which TOC easily elutes, and in an environment with a high ozone water concentration that is unlikely to be used industrially, so it can be used as is without rewriting even when used in an environment with a lower ozone water concentration than the set conditions of this arithmetic formula and using materials from which TOC is less likely to elute. Also, if the water treatment environment in which the cleaning water treatment device is actually used (amount of water to be treated, current pure water supply amount, current ozone water concentration) is known from the arithmetic formula, the duration of the ozone water concentration required for sterilization and purification treatment can be obtained.

[0027] In addition, The ozone supply unit supplies ozone while suppressing the concentration of residual ozone water after treatment to less than 5.37 mg / L. This purifies organic matter such as bacteria in the treated water with ozone, making it reusable, while also sterilizing the inside of the filtration mechanism, suppressing the reaction between ozone and resin components in the flow path after the filtration mechanism, preventing deterioration, and suppressing the generation of slime in the filters and ion exchange resin, thereby preventing the generation of organic matter due to slime and ultimately extending the life of the entire device.

[0028] Also, Since calculations can be performed using a data table, rapid calculation processing is possible, making it possible to quickly adjust the TOC concentration in cleaning water treatment equipment for semiconductor and liquid crystal manufacturing and electronic component manufacturing.

[0029] According to the invention of claim 4, the discharge amount and the amount of the water to be treated are controlled according to the TOC concentration in the water to be treated so as to suppress the TOC concentration in the water to be returned to the cleaning treatment unit to a predetermined concentration or less. pure water The TOC concentration adjusting means controls the discharge of the water to be treated according to the supply amount of pure water This allows products such as electronic components and liquid crystal glass substrates brought into the cleaning processing section to be cleaned for a long period of time with pure water of stable quality, preventing deterioration of product quality and improving manufacturing yields.

[0030] According to the invention of claim 5,By continuously supplying a predetermined amount of ozone, the total supply of ozone is increased, making it possible, for example, to clean large treated components and effectively sterilize and purify treated water that contains a large amount of bacteria and organic matter.

[0031] According to the invention of claim 6, an arithmetic expression or a data table Since calculations can be performed using this method, rapid calculation processing is possible, and the TOC concentration can be quickly adjusted in the treatment of cleaning water used in semiconductor manufacturing, liquid crystal manufacturing, and electronic component manufacturing. [Brief description of the drawings]

[0035] [Figure 1] 1 is a schematic diagram showing one embodiment of a cleaning water treatment device according to the present invention; [Diagram 2] FIG. 1 is a block diagram showing a deterioration test device for an ion exchange resin / filtration device. [Diagram 3] 1 is a graph showing a change in concentration of an initial ozone water concentration of 5.37 mg / L. [Figure 4] 1 is a graph showing a change in concentration of ozone water with an initial concentration of 12.5 mg / L. [Diagram 5] This is a micrograph of a filter with an ozone water concentration of 0 mg / L. [Figure 6] This is a micrograph of a filter containing ozone water at a concentration of 5.5 mg / L. [Figure 7] This is a micrograph of a filter containing ozone water at a concentration of 12.7 mg / L. [Figure 8] FIG. 1 is a block diagram of a TOC elution test. [Figure 9] FIG. 1 is a block diagram of a TOC elution test with some parts omitted. [Figure 10] 1 is a graph showing measured values ​​of TOC concentration over time when the amount of ozone generated is changed. [Figure 11] 1 is a graph showing the relationship between ozone water concentration and TOC elution amount. [Figure 12] 1 is a graph showing the amount of ozone supplied and the measured values ​​of the concentration of ozone water. [Figure 13]1 is a graph showing changes in ozone water concentration during intermittent operation in which ozone supply / stop is repeated. [Figure 14] 13 is a graph showing a simulation result of the TOC concentration of the water to be treated when a constant amount of the water to be treated is continuously discharged and a constant amount of pure water is continuously supplied, with the ozone supply time being changed. [Figure 15] 11 is a graph showing a simulation result of the ozone water concentration of the water to be treated when a constant amount of ozone is intermittently supplied. [Figure 16] 11 is a graph showing simulation results of the TOC concentration of water to be treated in cases where pure water is replenished and where it is not replenished when a constant amount of ozone is intermittently supplied. [Figure 17] FIG. 1 is a schematic diagram showing a case where the cleaning water treatment device of the present invention is applied to the final cleaning water tank among a plurality of cleaning water tanks in a plating process. [Figure 18] FIG. 2 is a schematic diagram showing a case where the washing water treatment apparatus of the present invention is applied to a semiconductor treatment vessel. [Figure 19] FIG. 1 is a schematic diagram showing a case where the cleaning water treatment device of the present invention is applied to a glass substrate manufacturing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The cleaning water treatment apparatus and cleaning water treatment method of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of one embodiment of the cleaning water treatment apparatus of the present invention.

[0037] In FIG. 1, the cleaning water treatment device 12 comprises a cleaning water storage section 13, a sterilization and purification unit 14, a filtration mechanism section 15 and a control device 16. The cleaning water storage section 13 and the sterilization and purification unit 14 are connected to each other in a circulating manner via an inflow flow path 17 and an outflow flow path 18. The cleaning water storage section 13 and the filtration mechanism section 15 are connected by a filtration flow path 19. The cleaning treatment section 11 and the cleaning water storage section 13, and the filtration mechanism section 15 and the cleaning treatment section 11 are connected by a circulation flow path 20. A TOC concentration measuring means 21 and a TOC concentration adjusting means 22 are provided in the circulation flow path 20 downstream of the filtration mechanism section 15.

[0038] The cleaning water storage section 13 is a water tank for storing the pure water used in the cleaning process of the target member in the cleaning process section 11 as the water to be treated, by flowing it in via the circulation flow path 20. The cleaning water storage section 13 is connected to an inflow flow path 17 and an outflow flow path 18 that are provided to be able to circulate between the cleaning water storage section 13 and the sterilization and purification unit 14, as well as a filtration flow path 19 to the filtration mechanism section 15.

[0039] The sterilization and purification unit 14 is a unit that sterilizes and purifies the water to be treated that is supplied from the cleaning water storage section 13 by a pump (not shown) provided inside the unit. The water to be treated stored in the cleaning water storage section 13 is sterilized and purified while circulating between the cleaning water storage section 13 and the sterilization and purification unit 14 through an inflow flow path 17 and an outflow flow path 18 that are connected between the sterilization and purification unit 14 and the cleaning water storage section 13 in a circulatory manner. The water to be treated is circulated between the cleaning water storage section 13 and the sterilization and purification unit 14 by a circulation pump (not shown) provided in the sterilization and purification unit 14.

[0040] The sterilization and purification unit 14 includes an ozone supply section that supplies ozone, an ultraviolet irradiation section that irradiates ultraviolet light, and a photocatalytic action section that activates photocatalysis, and performs sterilization and purification treatment of the water to be treated by organically combining each function. The sterilization and purification unit 14 is only required to include at least the ozone supply section, and the ultraviolet irradiation section and the photocatalytic action section can be omitted as necessary. The ozone supply section, the ultraviolet irradiation section, and the photocatalytic action section will be briefly described below.

[0041] The ozone supply section is a section that supplies ozone to the water to be treated that is supplied from the cleaning water storage section 13 via the inflow flow path 17, and is equipped with an ozonizer that generates ozone using air as a raw material, and an ejector that is provided in the inflow flow path 17 and supplies ozone to the water to be treated flowing within the flow path to mix it.

[0042] An ozonizer provides a discharge gap between an earth electrode and a dielectric body to which a high-voltage electrode is attached, and applies a high voltage between the earth electrode and the dielectric body to generate a discharge and generate ozone in the air flowing through the discharge gap. The ejector is made of resin such as fluororesin, ceramic, or metal, and mixes the water to be treated flowing through the inflow passage 17 with ozone (and dissolved oxygen) supplied from the ozonizer to create a fine-bubble mixed liquid (ozone water).

[0043] The ultraviolet irradiation section and the photocatalytic action section that activates the photocatalyst are integrated into an ultraviolet / photocatalyst unit. The ultraviolet / photocatalyst unit has an ultraviolet light source in the center, and a protective inner glass tube is provided on the outer periphery of this ultraviolet light source. An outer glass tube having a predetermined inner diameter is provided on the outer periphery of the inner glass tube around the ultraviolet light source, and a flow path for the water to be treated is formed between this outer glass tube and the inner glass tube. A photocatalyst, which is the photocatalytic action section, is disposed within this flow path.

[0044] The photocatalyst utilizes a photocatalyst that does not peel off by oxidizing the surface of a metallic titanium base material to produce titanium oxide, and is formed, for example, by coating titanium dioxide on the surface of a material such as titanium or a titanium alloy made of a mesh, titanium wire, an aggregate of fibrous titanium material, or other porous titanium material.

[0045] The ultraviolet light source is located in the center of the ultraviolet / photocatalyst unit, making the entire unit compact, and ultraviolet light is efficiently irradiated onto the water being treated, disinfecting the water and decomposing organic matter to perform the disinfection and purification process.

[0046] As shown in Fig. 1, the filtering mechanism 15 is composed of a filtering device 26 and an ion exchange resin 27. Filters such as a hollow fiber membrane filter and an activated carbon filter can be housed inside the filtering device 26, but in order to effectively filter bacteria contained in the water to be treated and organic matter including dead bacteria, it is preferable to use hollow fiber membranes of a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane). As the container of the filtering device 26 to contain these hollow fiber membranes, 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.

[0047] The ion exchange resin 27 is used to remove salt components such as calcium, sodium, chloride, and sulfate from the water to be treated that cannot be removed by ozone treatment or filtration treatment, and a mixture of a cation exchange resin that exchanges cations and an anion exchange resin that exchanges anions (negative ions) may be used. When the water to be treated is pure water, materials such as FRP, stainless steel, or iron lined or coated with Teflon (registered trademark) are often used as containers for these ion exchange resins, and these materials are also used when the water to be treated is ultrapure water.

[0048] The control device 16 is composed of a control unit 16a and a memory unit 16b. The control unit 16a is provided so as to be able to control the ozone supply unit and the TOC concentration adjustment means 21 of the sterilization and purification unit 14, and the memory unit 16b stores an arithmetic expression for calculating the amount of water to be treated supplied to pure water, or the amount of water to be treated discharged and the amount of pure water supplied. In the figure, the dashed lines connecting the control device 16 to the sterilization and purification unit 14, the TOC concentration measurement means 21, and the TOC concentration adjustment means 22 indicate signal transmission paths.

[0049] Here, in the course of researching and developing a purification treatment device and purification method that can be retrofitted to existing cleaning equipment used to clean semiconductor manufacturing, liquid crystals, and plated electronic components, and that can effectively purify the cleaning water to make it reusable for a long period of time, the inventors have confirmed that simply sterilizing and purifying with ozone is not sufficient to prevent the increase of bacteria at the point of use, and that it is necessary to supply ozone to the cleaning water storage section.

[0050] On the other hand, it was also confirmed that when ozone is present in the cleaning water storage section, TOC dissolves from the plastic impeller of the pump that circulates the treated water installed in the sterilization and purification unit, the plastic filter housing that contains the hollow fiber membrane filter of the filtration device, and the plastic cylinder that contains the ion exchange resin.

[0051] For these reasons, when the water to be treated in the cleaning water storage unit 13 is sterilized with ozone, it is necessary to sterilize the pure water after the treatment to a state suitable for reuse, and also to prevent the ozone contained in the pure water after the treatment from eluting TOC from each of the resin parts. To achieve this, the ozone water concentration is set to a value that can sterilize the water to a state suitable for reuse after the treatment, while suppressing the concentration of the ozone water to a value that can prevent the elution of TOC from each of the resin parts.

[0052] The above-mentioned storage unit 16b stores an arithmetic expression that can determine the amount of water to be treated and the amount of pure water to be supplied according to the ozone water concentration and TOC concentration of the water to be treated. By controlling the amount of water to be treated and the amount of pure water to be supplied by the control unit 16a based on this arithmetic expression, it becomes possible to bring the ozone water concentration to a level that sterilizes the treated water so that it can be reused, and to suppress the elution of TOC from resin parts.

[0053] In order to set the calculation formula of the memory unit 16b, it is required to set the ozone water concentration that can sterilize the treated water to a state where it can be reused after treatment as described above, while suppressing the TOC concentration. In this case, the sterilization ability of the treated water is maximized, while the effect on the resin parts such as the filtration mechanism unit 15 is minimized, thereby maintaining their functionality.

[0054] In order to obtain treated water with an ozone water concentration that maximizes the sterilization ability, it is necessary to clarify the effect of the difference in ozone water concentration on the cleaning water storage unit 13 as well as on the filter and ion exchange resin 27 in the cleaning water treatment device 12, or on the FRP cylinder and filter housing of the container in which they are filled, the pump impeller, the O-ring, and other resin parts. Therefore, a deterioration test using ozone water was carried out on the filtration device 26 and the ion exchange resin 27. In the deterioration test, the conditions under which the filtration device 26 and the ion exchange resin 27 deteriorate were confirmed by changing the ozone water concentration or the contact time with ozone, and the relationship between the ozone water concentration and the oxidation deterioration of the filtration device 26 and the ion exchange resin 27 was confirmed.

[0055] In this case, the desired ozone water concentration (mg / L) can be obtained by setting the amount of ozone generated per hour (g / h). The applicant estimated the amount of ozone generated to obtain the optimal ozone water concentration to be 2.0 g / h, and conducted a test for an ozone water concentration of 5.37 mg / L at this time, thereby suppressing the concentration of residual ozone water after ozone treatment by the ozone supply unit to less than 5.37 mg / L. In addition, for comparison, tests were conducted for an ozone generation amount of 0.3 g / h (ozone water concentration of 1.31 mg / L) and a case where the ozone generation amount was greater than 2.0 g / h (ozone water concentration of 5.37 mg / L). Note that all the target water at this time was ion-exchanged water as pure water.

[0056] Using the test device 100 shown in FIG. 2, the conditions under which the ion exchange resin 27 and the filtration device (filter) 26 deteriorate are confirmed, and the relationship between these and the oxidative deterioration caused by the concentration of ozone water is clarified.

[0057] In the figure, a PSA (oxygen concentrator) 101 is used as a generator of gas raw material, and this PSA is connected to an ozonizer 125 (Ozone Generator OZS-EP3-20, Masuda Laboratory Co., Ltd.), and the ozone gas generated by this ozonizer 125 is pressurized and dissolved by a mixing pump 103 (M20NPD04Z, Nikuni Co., Ltd.) to produce high-concentration ozone water. Ozone water produced by ozone generating unit 136 that generates ozone is stored in water tank 130, and this ozone water is sent to ion exchange resin 27 or filtration device (filter) 26 via water supply pump 104. Water is passed through ion exchange resin 27 or filtration device 26 after adjusting the flow rate to an appropriate level using flow meter 106 and adjustment valve 136 provided in the path.

[0058] The concentration of the ozone water accumulated in the test water tank 130 was measured at any time using an ozone water concentration meter 110 (Oxtrotec Co., Ltd., ozone water concentration meter OZM-7000LN).

[0059] In FIG. 2, one set of filter 26 / ion exchange resin 27 is provided in series with respect to the flow path, but a plurality of filters / ion exchange resins may be provided in parallel.

[0060] In the deterioration test of ion exchange resin 27 by ozone water, Organo ion exchange resin Amberlite MB2 and the container filled with ion exchange resin 27 were made of PVC.

[0061] In a deterioration test of the ion exchange resin 27 using the test device 100, the test device 100 was operated for 30 minutes on ion exchange water stored in the test water tank 130, and the ozone water concentration was measured. Thereafter, the water pump 104 was operated to pass ozone water at a predetermined concentration through the ion exchange resin 27 for a predetermined time. After passing the ozone water through the ion exchange resin 27, various analyses were performed to confirm the degree of deterioration.

[0062] The various conditions for carrying out the above tests are as follows: PSA supply gas flow rate: 2.5~2.7 L / min PSA supply gas pressure: 0.078~0.081 MPa Mixing pump discharge pressure: 0.29~0.33 MPa Ozonizer flow rate: 1.6~1.7 L / min Water amount: 70L Water flow time: 8 hours, 72 hours

[0063] The transition (change) of the ozone water concentration during testing using the above-mentioned testing device 100 is shown in the graphs of Figures 3 and 4. Figure 3 shows the change in ozone water concentration versus operation time when attempting to set the ozone water concentration to approximately 5.37 mg / L, while Figure 4 shows the change in ozone water concentration versus operation time when attempting to set the ozone water concentration to greater than 5.37 mg / L. In both graphs of Figures 3 and 4, water flow through the ion exchange resin 27 starts at the point indicated by the arrow.

[0064] In the case of Fig. 3, the ozone water concentration is 5.37 mg / L when the test water that has passed through the ozonizer (ozone supply unit) 125 and accumulated in the test water tank 130 starts to pass through the ion exchange resin 27. After passing through the ion exchange resin 27, the ozone water concentration decreases due to a reaction between the ion exchange resin 27 and ozone, and the average ozone water concentration during the water passing test becomes 4.07 mg / L. Since the effect of the reaction between the ion exchange resin 27 and ozone becomes large after passing through the ion exchange resin 27, the definition for setting the ozone water concentration is set to satisfy the requirement that the concentration of the residual ozone water after treatment by the ozonizer 125 be suppressed to less than 5.37 mg / L.

[0065] 4, the ozone water concentration at the beginning of the water flow is about 12.5 mg / L. Immediately after the water starts to flow through ion exchange resin 27, the ozone water concentration drops due to the reaction between ion exchange resin 27 and ozone as described above, and although there are some fluctuations depending on the water temperature change and the water flow time, the ozone water concentration generally remains at 6 to 9 mg / L, and the average ozone water concentration after the water flows through ion exchange resin 27 is 7.44 mg / L. In this case, regardless of the state from the beginning of water flow until the specified operating time (8 hours), the ozone water concentration never falls below 5.37 mg / L, and does not overlap with the ozone water concentration conditions of the test in Figure 3.

[0066] The analytical results of the ion exchange resin 27 obtained by the above test are shown below. Regarding the effect of ozone on ion exchange resins, it is assumed that when ion exchange resins are oxidized by ozone, functional groups are removed and the resin matrix is ​​oxidized and expands. For this reason, the "total exchange capacity," "neutral salt decomposition capacity," and "water retention capacity" were measured as analytical items to grasp the deterioration.

[0067] 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 during the analysis, each ion exchange resin was separated and various values ​​were measured.

[0068] The test was carried out in two parts, and the analysis results of the ion exchange resin when tested with ozone water concentrations of 1.31mg / L and 5.37mg / L at the beginning of the water flow are shown in Table 1. Table 1 lists the generally recommended performance standard values ​​to show the performance of the ion exchange resin when no ozone water is passed through it.

[0069] Even when the ozone water concentration was 1.31 mg / L at the beginning of the water flow, the ozone water concentration decreased after the ozone water was passed through the ion exchange resin due to a reaction between the ion exchange resin and ozone, and the average ozone water concentration during the water flow test was 0.68 mg / L.

[0070] [Table 1]

[0071] In Table 1, when comparing the standard value 1 with the analytical values ​​of tests 1A and 1B, a reaction between the ion exchange resin and ozone water was observed at an ozone water concentration of less than 5.37 mg / L. However, in terms of the neutral salt decomposition amount and water retention capacity, no clear deterioration was observed compared to the standard values ​​for either the cation exchange resin or the anion exchange resin in both tests 1A and 1B, and practical functionality as an ion exchange resin was ensured.

[0072] Meanwhile, the analysis results when the ozone water concentration is 5.37 mg / L or more are shown in Table 2. Table 2 lists various measurement values ​​of the ion exchange resin when the water flow time is 8 hours and 72 hours, in the generally recommended standard value, in a "no water flow" state where no ozone water is passed, and when the ozone water concentration is 5.37 mg / L or more (initial water flow concentration is 12.5 mg / L).

[0073] [Table 2]

[0074] In Test 2A in Table 2 (initial ozone water concentration in the water flow: 12.5 mg / L, ozone water concentration in the water flow: 7.5 mg / L, water flow time: 8 hours), the neutral salt decomposition capacity of cation exchange resin A was below the standard value, confirming a decrease in ion exchange capacity. On the other hand, the water retention capacity exceeded the upper limit of the standard value, confirming that the resin had swelled and deteriorated due to the oxidizing action of ozone. When the water flow time was further extended to 72 hours (Test 2B), the total exchange capacity of anion exchange resin B also fell below the reference value, indicating that deterioration of the ion exchange resin had progressed. From these findings, it can be seen that the ion exchange capacity decreases as the time for which ozone water is passed through increases, and it can be said that under the conditions of this test, it is possible to determine whether or not the ion exchange resin has deteriorated by comparing the results with the standard value after a water flow time of 8 hours.

[0075] In addition, in this test, the particle size of the ion exchange resin after passing ozone water was measured, observed under a microscope, and the amount of TOC eluted was also confirmed. In particular, it was confirmed that physical fragmentation occurs in the anion exchange resin as the time of passing ozone water increases, and the particle size becomes smaller. It was also confirmed that the TOC concentration during the water passing test increases as the water passing time increases. This is thought to be because the polymer organic matter that makes up the ion exchange resin is oxidized by ozone, causing the resin structure itself to lose its shape, resulting in the elution of the organic matter that is the material. For these reasons, when ozone water, which is an oxidizing agent, is passed through an ion exchange resin at an ozone water concentration of 7.5 mg / L for more than 8 hours, there is concern that the ion exchange performance will decrease and organic matter will be eluted, making it difficult to practically use an ion exchange resin in this ozone water.

[0076] Based on the results in Table 1, if the ozone water concentration is less than 5.37 mg / L, the sterilization effect on the ion exchange resin contained in the filtration mechanism is maintained while preventing deterioration without interfering with its function, thereby reducing the frequency of replacement of the ion exchange resin and extending the life of the device.

[0077] Next, a deterioration test of the filtering device 26 (filter) is carried out using the testing device 100 shown in FIG. High-concentration ozone water produced from pure water by the test device 100 was sent to the filter 26 while maintaining the concentration constant, and the progress of deterioration of the filter 26 was confirmed when the contact time was changed.

[0078] The filter used in the test was manufactured by Nippon Filter Co., Ltd., and the housing type was NPH-NPP-10, and the filter model was CW-1 (material: polypropylene).

[0079] The procedure for the deterioration test of the filtration device 26 using the test device 100 was the same as the deterioration test procedure for the ion exchange resin shown in

[0061] , and the surface of the filter after passing the ozone water was observed under a microscope.

[0080] The various conditions for carrying out the above tests are as follows: PSA supply gas flow rate: 2.5~2.9 L / min PSA supply gas pressure: 0.078~0.085 MPa Mixing pump discharge pressure: 0.3 MPa Ozonizer flow rate: 1.6 L / min Water amount: 70L Water flow time: 8 hours, 24 hours

[0081] After the above test, each filter 26 of the filtration device is subjected to optical observation and SEM observation using a microscope. The observation conditions are as follows: Analytical equipment: Optical observation: Digital microscope (Keyence VHX-1000) SEM observation: Electron probe microanalyzer (Shimadzu EPMA-1610) Analysis method: After optical observation of the filter surface, gold vapor deposition (ion sputtering) is performed and SEM observation is performed.

[0082] Microscopic photographs of the filter (type CW-1) of the filtration device from the above test are shown in Figures 5 to 7. In each figure, the upper row shows a photograph observed with a microscope, and the lower row shows an SEM photograph taken with an electron microscope. Figure 5 shows the state after 0 hours of water flow (no load of ozone water), Figure 6 shows the state after 24 hours of water flow with an average ozone water concentration of 5.5 mg / L in the water, and Figure 7 shows the state of the filter after 24 hours of water flow with an average ozone water concentration of 12.7 mg / L in the water.

[0083] From the observation of the photographs in Figures 5 to 7, particularly the electron microscope (SEM) images in the lower row, it was confirmed that as the concentration of ozone water increased, the number of breaks on the fiber surface and the adhesion of broken fiber fragments to the surface increased, indicating that the deterioration of the polymer resin due to ozone was progressing.

[0084] In Figure 6, the ozone water concentration when water was passed was 5.5 mg / L (equivalent to an ozone water concentration of 5.37 mg / L), but no significant deterioration was observed compared to the photograph in Figure 5, which shows no load from ozone water, and it can be determined that with an ozone water concentration of about 5.5 mg / L (equivalent to 5.37 mg / L), there is no deterioration to the extent that it impairs the filter's performance. On the other hand, when water was passed through with an ozone water concentration of 12.7 mg / L, exceeding 5.37 mg / L, clear deterioration of the filter surface was confirmed, as shown in Figure 7.

[0085] For these reasons, in the deterioration test of the filtration device described above, if the ozone water concentration is less than 5.5 mg / L, deterioration to the extent that it impairs the performance of the filter does not occur. On the contrary, the ozone remaining in the treated water fully activates the sterilization action of the filtration device (filter) that constitutes the filtration mechanism, preventing the filter from becoming slimy, thereby maintaining the performance of the filtration device (filter). In turn, this reduces the frequency of filter replacement and extends the life of the device.

[0086] From the above, in the case of the filtration device (filter) alone, if the ozone water concentration is less than 5.5 mg / L, it is possible to prevent deterioration while maintaining the sterilization effect and without impeding its function. However, when considering the entire filtration mechanism section consisting of the filtration device (filter) and ion exchange resin, if the ozone water concentration is less than 5.37 mg / L, which was confirmed in the ion exchange resin deterioration test, it is possible to prevent deterioration while maintaining the sterilization effect of the entire filtration mechanism section and without impeding its function. In turn, this will reduce the frequency of replacement of the filtration membrane and ion exchange resin and extend the life of the device.

[0087] Next, a test was conducted to clarify the relationship between the ozone water concentration and the TOC concentration. Figures 8 and 9 show a schematic block diagram for testing the TOC elution state into the device by ozone treatment, and the same parts as those of the above-mentioned test device are indicated by the same reference numerals. The equipment used in the test was a test device 120 (Purekireizer (registered trademark) ZPVS3U11), an ozonizer 125 (Masuda Laboratory Co., Ltd. ozone generator OZS-EP3-20), and an ozone water concentration meter 110 (Okitrotec Co., Ltd. ozone water concentration meter OZM-7000LN). In the figure, 111 is a sensor box that measures pH, ORP, water temperature, and conductivity. Also, 112 is a flow meter, and 118 is wastewater. Also, 121 is a circulation pump built into the test device 120. Also, 123 is a compressor (air compressor), 124 is a flow meter, and 128 is a flow control valve. Also, 130 is a test tank and 135 is a valve.

[0088] The test method was a water passing test for FRP cylinder 153, in which the ozone water concentration introduced into test device 140 was changed to three types, and test device 140 was operated for 30 minutes using ion-exchanged water (pure water) to adjust to a predetermined concentration. Ozone water adjusted to three types of ozone water concentrations (ozone generation rate of 0.5 g / h, 1.0 g / h, 2.0 g / h) by ozonizer 125 and ejector 126 was passed through FRP cylinder 153 for 8 hours by operating water pump 131. The FRP cylinder 153 used in this test was a container containing ion exchange resin (Organo cartridge water purifier Amberlite MB2 capacity 5 L) (no ion exchange resin was stored).

[0089] The test conditions are as follows: [Test conditions] Test water: Ion-exchanged water Test water volume: 40L Circulation flow rate: 20L / min (1 turn 120 seconds) Ozone generation rate: 0.5g / h 1.0g / h 2.0g / h

[0090] As a result of an experiment conducted by the present inventors, it was confirmed that the amount of TOC eluted from a resin component in contact with ozone water increases linearly in approximately proportion to the concentration of the ozone water according to the amount of ozone generated and the contact time between the ozone water and the resin component, as shown in Fig. 10. By organizing the results of this experiment by contact time as shown in Fig. 11, the relationship between the ozone water concentration (mg / L) and the eluted TOC concentration (mg / L) can be organized by ozone contact time.

[0091] In Figure 11, the relationship between the ozone water concentration (mg / L) and the eluted TOC concentration (mg / L) when the contact time between the ozone water and the resin component is 1 hour is approximately linear, so the relationship between the eluted TOC concentration (mg / L) when the ozone water is in contact with the resin component per unit time can be approximated by the following equation, where the ozone water concentration is x (mg / L) and the eluted TOC concentration is y (mg / L).

[0092] (Formula 1) y=0.0036x+0.070 (1)

[0093] In addition, to investigate the change in ozone supply time versus ozone water concentration, an experiment was conducted to measure the change in ozone supply time (min) versus ozone water concentration (mg / L) for each ozone supply amount, with three ozone supply amounts: 0.5 (g / h), 1.0 (g / h), and 2.0 (g / h). For each ozone supply amount, the change in ozone water concentration (mg / L) versus ozone supply time (min) was measured, and a cubic approximation curve of the relationship between ozone generation time t (min) and ozone water concentration x (mg / L) based on the measurement results is shown in Figure 12.

[0094] The rate of increase in the ozone water concentration for each ozone supply amount can be calculated from the slope of the tangent at the time of rising of the cubic approximation curve shown in FIG. 12. In addition, the rate of increase in the ozone water concentration for ozone supply amounts other than these three can be calculated by linear interpolation from the rate of increase in the ozone water concentration per unit time for these three amounts, or can be calculated from the actual measurement results by 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 for ozone supply times up to about 10 minutes. It was also confirmed that there is an upper limit to the increase in the ozone water concentration even if the ozone supply is continued, regardless of the ozone supply amount.

[0095] In addition, an experiment was conducted to confirm the change in ozone water concentration when ozone supply / stop was repeated during intermittent operation. In the experiment, the ozone supply rate was set to 2.0 (g / h), and the change in ozone water concentration was measured in the following cases: 1 minute of ozone supply and 9 minutes of ozone stop were repeated, 5 minutes of ozone supply and 5 minutes of ozone stop were repeated, and 30 minutes of ozone supply followed by 30 minutes of ozone stop.

[0096] The measurement results are shown in Figure 13. In each case, the ozone water concentration increased almost linearly immediately after the start of ozone supply, and then decreased exponentially after ozone supply was stopped. This decrease is believed to be due to the self-decomposition of ozone. When observing the decrease in the ozone water concentration in detail, the ozone water concentration decreased with roughly a half-life of 5 minutes for each combination of ozone supply time and stop time. In addition, the ozone concentration was almost zero about 30 minutes after ozone supply was stopped.

[0097] By creating an arithmetic formula based on knowledge gained from the above experiments and storing it in the memory unit 16b, it is possible to obtain the rate of increase in the ozone water concentration of the water to be cleaned from the amount of ozone supplied, and to obtain the ozone water concentration of the water to be treated from the rate of increase in the ozone water concentration and the ozone supply time. It is also possible to obtain the decrease in the ozone water concentration after the ozone supply is stopped. Furthermore, it is possible to obtain the TOC concentration of the water to be treated from the obtained ozone water concentration of the water to be treated.

[0098] 1, TOC concentration measuring means 21 measures the TOC concentration of the water to be treated flowing through the circulation flow path 20. The treatment purpose of the washing water treatment device 12 is to suppress the TOC concentration of the water to be washed to a predetermined concentration or less, and since the TOC concentration of pure water in particular needs to be controlled to 1.0 mg / L or less (a predetermined value or less), the TOC concentration measuring means 21 is provided so that the control device 16 can monitor the treatment status and determine whether the treatment status is satisfactory.

[0099] The TOC concentration adjusting means 22 includes an electric valve, an electric pump, and a flow meter (not shown). The electric valve is controlled by the control unit 16a to discharge a predetermined amount of the water to be treated. The electric pump is also controlled by the control unit 16a to supply a predetermined amount of pure water from a pure water production system (not shown) to the circulation flow path 20.

[0100] The reason for discharging the water to be treated and supplying pure water in this manner using the TOC concentration adjustment means 22 is that since it is difficult to remove TOC once it has dissolved into the water to be treated, by discharging the water to be treated that contains TOC, the TOC dissolved in the water to be treated is discharged and the amount of TOC present in the cleaning processing unit 11 and the cleaning treatment device 12 is reduced, and by supplying the same amount of pure water as the water to be treated that has been discharged, the TOC concentration of the cleaning water present in the cleaning processing unit 11 and the cleaning treatment device 12 is reduced and maintained below a predetermined value.

[0101] In addition, to ensure that the cleaning process of the workpieces in the cleaning process unit 11 is carried out reliably, a certain amount of cleaning water must be present inside the cleaning process unit 11 and the cleaning treatment device 12, but the amount of cleaning water naturally decreases as the cleaning process proceeds due to the evaporation of the cleaning water from the cleaning tank and the cleaning water adhering to the workpieces being carried out of the cleaning tank when the workpieces are cleaned, so it is necessary to replenish the amount of pure water to make up for this natural decrease. This replenishment also contributes to lowering the TOC concentration.

[0102] Next, the operation of the cleaning water treatment device of the present invention will be described. As shown in FIG. In the cleaning water treatment device 12, the pure water used for cleaning the treated members in the cleaning processing unit 11 flows as the water to be treated through the supply flow path 23 and is stored in the cleaning water storage unit 13 (volume: 200 L to 300 L). The water to be cleaned stored in the cleaning water storage unit 13 is sent to the sterilization and purification unit 14 through the inflow flow path 17 by a pump (not shown).

[0103] A predetermined amount of ozone (and dissolved oxygen) is mixed into the water to be treated sent to the sterilization and purification unit 14 from an ejector provided in the ozone supply section, and a mixed liquid (ozonated water) is produced in which fine bubbles of ozone are dissolved in the water to be treated in the form of bubbles. Note that the amount of ozone to be supplied at this time must be determined by comprehensively judging the capacity of the cleaning water storage section 13, the amount of water to be treated, and the upper and lower limits of the ozone water concentration for performing effective sterilization and cleaning treatment, since there is a risk of shortening the life of the filter and ion exchange resin 27 of the filtration device 26 in the downstream filtration mechanism section 15 if the concentration of ozone water in the water to be treated becomes high, and this will increase the amount of TOC eluted from the resin filter housing that contains the hollow fiber membrane filter and the resin cylinder that contains the ion exchange resin.

[0104] Due to the bactericidal effect of the supplied ozone, most of the bacteria in the water being treated are killed, and most of the organic matter, including the corpses of the killed bacteria, is decomposed.

[0105] When the water to be treated containing ozone flows into the ultraviolet / photocatalyst unit located after the ozone supply section, it passes through an ultraviolet light source and a photocatalyst. When the water to be treated with ozone dissolved in it is irradiated with ultraviolet light, a radical called ·OH (hydroxyl radical or OH radical) (a chemical species with an unpaired electron that is highly activated) is generated.

[0106] This ·OH is highly activated, so it can sterilize almost all of the bacteria remaining in the water that was not sterilized when ozone was applied in the ozone supply unit, and can also decompose almost all of the organic matter remaining in the water that was not decomposed. In addition, since the OH radical disappears in a very short time, it does not damage the filtration device 26 or the ion exchange resin 27. The OH radical is generated by the action of ozone and ultraviolet irradiation, which reliably sterilizes and purifies the bacteria and organic matter remaining in the cleaning water storage unit 13, and can extend the life of the filtration device 26 and the ion exchange resin 27 without damaging them. Furthermore, the more effective generation of OH radicals through ultraviolet irradiation and the action of photocatalysis, combined with low concentration ozone, i.e., organic bonding, reliably sterilizes and purifies bacteria and organic matter remaining in the cleaning water storage section 13, and also extends the life of the filtration device 26 and ion exchange resin 27 without damaging them.

[0107] The water to be treated that has been subjected to the sterilization and purification treatment in the ultraviolet / photocatalyst unit is returned to the cleaning water storage section 13 via the outflow passage 18.

[0108] In this way, the water to be treated stored in the cleaning water storage section 13 is sterilized and purified while circulating between the cleaning water storage section 13 and the sterilization and purification unit 14, so that the ozone remaining in the water to be treated returned to the cleaning water storage section 13 exerts a bactericidal effect even within the cleaning water storage section 13, suppressing the growth of bacteria and suppressing the occurrence of biofilms on the walls, etc., of the cleaning water storage section 13.

[0109] In addition, after being sterilized and purified in the sterilization and purification unit 14, the ozone water is not immediately sent to the filtration mechanism section 15, but is returned to the cleaning water storage section 13 and then mixed with the water to be treated stored in the cleaning water storage section 13. Therefore, the ozone water concentration of the water to be treated stored in the cleaning water storage section 13 as a whole is diluted, and since the ozone is decomposed while stored in the cleaning water storage section 13, the ozone water concentration of the water to be treated sent to the filtration mechanism section 15 decreases.

[0110] On the other hand, in order to prevent the proliferation of bacteria in the cleaning treatment unit 11, the cleaning water returned from the cleaning water treatment device 12 to the cleaning treatment unit 11 contains ozone, and after being returned to the cleaning treatment unit 11, it is necessary to maintain a certain level of ozone water concentration even when it is mixed with the cleaning water stored in the cleaning treatment unit 11. According to the results of experiments by the present inventors, the sterilizing power of ozone is extremely strong, and an ozone water concentration of about 0.05 (mg / L) can sterilize almost all bacteria within a few minutes, so that the amount of ozone supplied from the ozone supply unit of the sterilization and purification unit 14 is sufficient at about 0.05 (g / h) even taking into account dilution and decomposition in the cleaning water storage unit 13, if the amount of water to be treated is about 40 (L).

[0111] In this way, the water to be treated whose ozone water concentration has been reduced to a certain extent in the cleaning water storage section 13 is sent to the filtration mechanism section 15 via the filtration flow path 19, but as described above, the amount of ozone supplied to the water to be treated from the ozone supply section of the sterilization and purification unit 14 is small, and the ozone water concentration in the water to be treated is also reduced due to the self-decomposition of ozone, so there is no risk of the residual ozone in the water to be treated damaging the filter or ion exchange resin 27 of the filtration device 26 of the filtration mechanism section 15 and shortening their lifespan. Moreover, in this embodiment, the low concentration of ozone is used to sterilize the inside of the filtration mechanism section 15 while minimizing TOC elution, and the water to be treated is controlled to have an ozone concentration sufficient for sterilization.

[0112] In addition, the sterilization and purification unit 14 kills most of the bacteria remaining in the water to be treated, and the water to be treated, in which most of the organic matter remaining in the water has been decomposed, is sent to the filtration mechanism section 15 via the filtration flow path 19, so that the filter of the filtration mechanism section is less likely to become clogged or the function of the ion exchange resin is less likely to deteriorate due to bacteria or organic matter, and the lifespan of these components can be extended.

[0113] The water to be treated sent from the cleaning water storage section 13 to the filtration mechanism section 15 is filtered in a filtration device 26 to remove bacteria and organic matter remaining in the water to be treated, and then the salt components in the water to be treated that cannot be removed by ozone treatment or filtration are removed in an ion exchange resin 27.Then, the water to be treated is returned to the cleaning treatment section 11 via the circulation flow path 20.

[0114] Incidentally, in the cleaning water treatment device 12 of the present invention, a low concentration of ozone is added to the water to be treated, which is returned to the cleaning treatment device 11 after the sterilization and purification treatment, in order to prevent an increase in bacteria in the cleaning treatment device 11. For this reason, TOC is eluted from the resin impeller in the sterilization and purification unit 14, the resin filter housing of the filtration device 26, and the resin cylinder of the ion exchange resin 27 into the water to be treated, which contains ozone, albeit at a low concentration.

[0115] Therefore, if the water to be treated after the sterilization and purification treatment is returned to the cleaning treatment unit 11 as it is, the TOC concentration of the cleaning water in the cleaning treatment unit 11 will gradually increase, and will eventually no longer satisfy the water quality requirements for pure water. In order to suppress the increase in the TOC concentration of the cleaning water in the cleaning treatment unit 11, the cleaning water treatment device of the present invention is provided with a TOC concentration adjustment means 22 in the circulation flow path 20 for the water to be treated, and before returning the water to the cleaning treatment unit 11, the water to be treated is discharged and pure water is supplied according to the ozone water concentration and TOC concentration of the water to be treated, thereby making it possible to suppress the TOC concentration of the cleaning water used in the cleaning treatment unit 11 to a predetermined value or less. In this embodiment, the TOC concentration adjustment means 22 is provided in the circulation flow path 20 immediately before the cleaning treatment unit 11, which is suitable for accurately adjusting the TOC concentration.

[0116] As described above, in the cleaning water treatment device 12, the pure water used for cleaning the parts to be treated in the cleaning treatment unit 11 is stored in the cleaning water storage unit 13 as the water to be treated, and the water to be treated is circulated between the cleaning water storage unit 13 and the sterilization and purification unit 14 while being continuously sterilized and purified. At the same time, the stored water to be treated is sent to the filtration mechanism unit 15 for filtering, and then the TOC concentration adjustment means 22 supplies pure water to the water to be treated, or drains the water to be treated and supplies pure water, depending on the ozone water concentration and TOC concentration of the water to be treated, and then returns the water to the cleaning treatment unit 11, thereby suppressing the TOC concentration of the cleaning water used in the cleaning treatment unit 11 to a predetermined value or below.

[0117] By performing sterilization and purification treatment while circulating the water to be treated between the cleaning water storage section 13 and the sterilization and purification unit 14, the water to be treated that has been sterilized and purified and contains dissolved ozone is returned to the cleaning water storage section 13, gradually reducing the organic matter and bacteria contained in the water to be treated in the cleaning water storage section 13 and suppressing the proliferation of bacteria in the cleaning water storage section 13.

[0118] As a result, the amount of organic matter and bacteria contained in the treated water sent from the cleaning water storage section 13 to the filtration mechanism section 15 is significantly reduced compared to when the water is not circulated in the sterilization and purification unit 14, thereby preventing the filter of the filtration device 26 from clogging and the functionality of the ion exchange resin 27 from decreasing due to the filtration of bacteria and organic matter.

[0119] In addition, the treated water sent from the cleaning water storage section 13 to the filtration mechanism section 15 may contain a low concentration of ozone. However, this ozone is at a low concentration and does not affect the function of the filter, etc., and does not damage the filter or ion exchange resin 27 of the filtration device 26 of the filtration mechanism section 15. Therefore, the growth of bacteria can be suppressed in the filtration mechanism section 15, the circulation flow path 20, and the cleaning treatment section 11.

[0120] In the filtration mechanism section 15, the filter (preferably a hollow fiber membrane of a UF membrane) of the filtration device 26 removes fine particles, bacteria, and high molecular weight organic matter, while the ion exchange resin 27 removes salt components such as calcium, sodium, chloride, and sulfate from the treated water that cannot be removed by ozone treatment or filtration treatment.

[0121] In addition, since the water to be treated contains ozone, albeit at a low concentration, the increase in TOC concentration due to TOC eluting from the plastic impeller, filter housing, cylinder, etc. is handled by the TOC concentration adjustment means 22 by supplying pure water to the water to be treated, or draining the water to be treated and supplying pure water, depending on the ozone water concentration and TOC concentration of the water to be treated, thereby suppressing the TOC concentration of the washing water to a predetermined value or below, and ultimately making it possible to reuse the water to be treated as pure water that meets water quality requirements.

[0122] In the cleaning water treatment device of the present invention, the treated water is subjected to the above-described sterilization and purification treatment and filtration treatment, and the TOC concentration is suppressed to a predetermined concentration or below. Therefore, the water can be reused as cleaning water (pure water) in the cleaning treatment section without adversely affecting the quality of the product. Furthermore, the pure water used in the cleaning treatment section can be saved over a long period of time, allowing for stable cleaning treatment, thereby reducing cleaning costs.

[0123] Next, a cleaning water treatment method using the cleaning water treatment device 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 and purification unit will be described. This cleaning water treatment method in which ozone is continuously supplied increases the total amount of ozone supplied by continuously supplying a predetermined amount of ozone, and can be applied, for example, to effectively sterilize and purify the water to be treated that contains a large amount of bacteria and organic matter after cleaning a large member to be treated.

[0124] When carrying out this cleaning water treatment method, the total volume of cleaning water to be treated (L) (for example, the capacity of a cleaning water tank provided in the cleaning treatment section), the amount of ozone supplied (g / h), and the ratio of the water to be treated to the total volume of cleaning water are input, and an arithmetic formula is called up from memory section 16b based on the TOC increase rate per unit time to sequentially calculate the amount of TOC (mg) contained in the total cleaning water, the amount of cleaning water discharged (L) (≒ amount of pure water supplied (L)), the amount of TOC (mg) contained in the total cleaning water after pure water is supplied, and the TOC concentration (mg / L) of the total cleaning water after pure water is supplied, and the change in the TOC concentration (mg / L) of the total cleaning water after pure water is supplied is calculated.

[0125] At this time, the total volume of washing water to be treated (L) and the amount of ozone supplied (g / h) are fixed values, but the ratio of the water to be discharged to the total volume of washing water can be changed arbitrarily. Therefore, by changing this value and determining the trend in the TOC concentration (mg / L) of the total washing water after pure water is supplied, it is possible to determine the ratio of the water to be discharged to the total volume of washing water such that the TOC concentration (mg / L) of the total washing water after pure water is supplied does not exceed 1.0 (mg / L), which is the standard for pure water.

[0126] Figure 14 shows the simulation results of the change in TOC concentration (mg / L) of all the washing water when the total washing water volume is 40 (L), the ozone supply rate is 0.5 (g / h), and the discharged water volume to be treated and the pure water supply rate are 3 (L / h). As shown in the figure, the TOC concentration of all the washing water does not exceed the TOC concentration of 1.0 (mg / L), which is the water quality requirement for pure water, even after the treatment time has passed.

[0127] As shown in Figure 12, the relationship between the amount of ozone supplied and the ozone water concentration in the treated water is such that the concentration of ozone water after ozone supply does not increase above a certain concentration. Therefore, from the figure, the ozone water concentration was set to 0.32 (mg / L), at which the ozone water concentration stabilizes when 0.5 (g / h) of ozone is supplied, and the increase rate of ozone relative to this ozone water concentration was calculated using the above-mentioned (Equation 1) and used in the simulation.

[0128] Therefore, when performing a cleaning water treatment method in which a predetermined amount of ozone is continuously supplied in the cleaning water treatment device of the present invention, by continuously supplying 0.5 (g / h) of ozone from the ozone supply section of the sterilization and purification unit 14 while discharging 3 (L / h) of the water to be treated by the TOC concentration adjustment means 22 and supplying pure water at a rate of 3 (L / h), the TOC concentration of the cleaning water used in the cleaning treatment section 11 can be suppressed to 1.0 (mg / L) or less.

[0129] Next, a case will be described in which the TOC concentration adjusting means supplies pure water in an amount equivalent to the amount of cleaning water that naturally decreases when cleaning the member to be cleaned in the cleaning processing unit, and a predetermined amount of ozone is intermittently supplied from the ozone supplying unit. Since the amount of pure water supplied in this cleaning water processing method corresponds to the amount of water that naturally decreases when the member to be cleaned is cleaned, the amount of expensive pure water used can be minimized to reduce cleaning costs. In addition, since the predetermined amount of ozone is supplied by intermittent supply that repeats supply for a certain period of time and stop for a certain period of time, the total amount of ozone supplied is not large, so that the method can be applied, for example, to a case where a small member to be cleaned is cleaned and the treated water that does not contain many bacteria or organic matter is sterilized and purified at low cost. Note that the cleaning water that naturally decreases during cleaning refers to the cleaning water that evaporates from the cleaning tank and the cleaning water that adheres to the member to be cleaned and is carried away when the member to be cleaned is cleaned.

[0130] When performing this cleaning water treatment method, by inputting the total amount of cleaning water (L) to be treated (for example, the capacity of a cleaning water tank provided in the cleaning processing unit), the amount of ozone supplied (g / h), the ratio of pure water supplied to the total amount of cleaning water, and the ON time (min) for supplying ozone and the OFF time (min) for stopping the supply, an arithmetic formula can be called up from the memory device 16b to calculate the change in ozone water concentration over treatment time based on the ozone water concentration increase coefficient corresponding to the amount of ozone supplied and the tendency for the ozone water concentration to decrease with a half-life of 5 minutes when the ozone supply is stopped, as well as the ozone water concentration of the water to be treated from this change in ozone water concentration over treatment time, and the trend in the TOC concentration (mg / L) of the total cleaning water can be calculated.

[0131] At this time, the total amount of cleaning water to be treated (L), the amount of ozone supplied (g / h), and the amount of pure water replenished to compensate for the natural decrease in cleaning water (L / min) are fixed values, but the combination of the ON time (min) when ozone is supplied and the OFF time (min) when ozone is not supplied can be changed arbitrarily. Therefore, by changing this ON time and OFF time to determine the trend in the TOC concentration (mg / L) of the total cleaning water, it is possible to determine a combination of the ON time for supplying ozone and the OFF time for stopping the supply that will prevent the TOC concentration (mg / L) of the total cleaning water after pure water is supplied from exceeding 1.0 (mg / L), which is the standard for pure water.

[0132] Figure 15 shows the results of a simulation of the change in ozone water concentration when the total cleaning water volume is 40 (L), the ozone supply rate is 0.5 (g / h), and the pure water supply rate is 2.7 (L / min), with the ON time for supplying ozone being 7 (min) and the OFF time for stopping the ozone supply being 3 (min), and Figure 16 shows the results of a simulation of the change in TOC concentration of all cleaning water at this time, with and without the supply of pure water. As shown in Figure 16, when pure water equivalent to the natural decrease in cleaning water is supplied, the TOC concentration of all cleaning water remains significantly below the TOC concentration of 1.0 (mg / L), which is the water quality requirement for pure water, even after the treatment time has passed.

[0133] Therefore, when performing the cleaning water treatment method of the present invention in which a predetermined amount of ozone is intermittently supplied, by continuously supplying 0.5 (g / h) of ozone from the ozone supply section of the sterilization and purification unit 14, appropriately setting the ON time for supplying ozone and the OFF time for stopping the supply, and supplying pure water equivalent to the natural decrease in the cleaning water, the TOC concentration of the cleaning water used in the cleaning treatment section 11 can be suppressed to 1.0 (mg / L) or less.

[0134] Next, a case where the cleaning water treatment device of the present invention is applied to a plating process will be described. The same reference numerals are used for parts with the same functions as those described above, and the description will be omitted. As shown in Fig. 17, in this plating process, a sterilization and purification unit 14 is connected to the final cleaning water tank 35 out of three cleaning water tanks provided in addition to the plating tank 31.

[0135] In this plating process, a recovery tank 32 is provided for recovering the plating liquid, and cleaning water tanks 33, 34, and 35 are provided for cleaning the object to be treated after plating.

[0136] The cleaning water tank 33 and the cleaning water tank 34 are connected to each other, and pure water supplied to the cleaning water tank 34 overflows the partition between the cleaning water tanks 33 and 34, flows into the cleaning water tank 33, and is discharged from a drain outlet 36 provided in the cleaning water tank 33.

[0137] Pure water for cleaning is stored in the cleaning water tank 35, and the cleaning water tank 35 and the sterilization and purification unit 14 are connected to each other so as to be able to circulate through an inflow flow path 17 and an outflow flow path 18, and the cleaning water tank 35 and the filtration mechanism section 15 are connected through a filtration flow path 19. Furthermore, the filtration mechanism section 15 and the cleaning water tank 35 are connected through a circulation flow path 20, and a TOC concentration measuring means 21 and a TOC concentration adjusting means 22 are provided in the circulation flow path 20.

[0138] The TOC concentration measuring means 21 may constantly measure the TOC concentration using an online TOC meter, or may collect cleaning water from the circulation flow path and measure the TOC concentration.

[0139] 17, the cleaning water tank 35 is the cleaning processing section 11 and also the cleaning water storage section 13. Therefore, the pure water used for cleaning the object in the cleaning water tank 35, which is the cleaning processing section 11, is sterilized and purified while circulating between the cleaning water tank 35 and the sterilization and purification unit 14, and is sent from the cleaning water tank 35 to the filtration mechanism section 15, where it is filtered, and then returned to the cleaning water tank 35, which is the cleaning processing section.

[0140] In this way, the cleaning water stored in the cleaning water tank 35, which is the cleaning water storage section 13, is sterilized and purified while circulating between the cleaning water tank 35 and the sterilization and purification unit 14, and is also filtered while circulating between the cleaning water tank 35 and the filtration mechanism section 15.Furthermore, depending on the ozone water concentration and TOC concentration of the water to be treated, the TOC concentration adjustment means 22 supplies pure water to the water to be treated, or drains the water to be treated and supplies pure water, thereby suppressing the TOC concentration, and the cleaning water in the cleaning water tank 35 is maintained in a reusable state as pure water that meets water quality requirements.

[0141] Next, a case where the cleaning water treatment apparatus of the present invention is applied to a semiconductor manufacturing apparatus will be described. The same reference numerals are used for parts with the same functions as those described above, and the description will be omitted. Fig. 18 shows a schematic diagram of a single-wafer cleaning apparatus 41, and shows a state in which pure water is sprayed from a nozzle 44 onto a wafer 43 that is placed on a turntable 42 and rotates to clean the surface of the wafer 43. The pure water used for cleaning is stored as the water to be treated in a cleaning water recovery tank 45 provided at the bottom of the single-wafer cleaning apparatus 41.

[0142] 18, the nozzle 44 and the turntable 42 form the cleaning processing section 11, and the cleaning water recovery tank 45 provided below the single-wafer cleaning apparatus 41 forms the cleaning water storage section 13.

[0143] In the single-wafer cleaning apparatus 41, similarly to the plating process of FIG. 17, the cleaning water stored in the cleaning water recovery tank 45, which is the cleaning water storage section 13, is sterilized and purified while circulating between the cleaning water recovery tank 45 and the sterilization and purification unit 14, and is also filtered while circulating between the cleaning water recovery tank 45 and the filtration mechanism section 15. Furthermore, the TOC concentration adjustment means 22 supplies pure water to the water to be treated, or drains the water to be treated and supplies pure water, depending on the ozone water concentration and TOC concentration of the water to be treated, thereby suppressing the TOC concentration, and the cleaning water in the cleaning water recovery tank 45 is maintained as reusable pure water that satisfies water quality requirements.

[0144] In the single-wafer cleaning apparatus 41 in Fig. 18, the water to be treated is treated as pure water and the water to be treated recovered in the cleaning water recovery tank 45 is treated so as to be reusable, but as long as the cleaning water discharged from the nozzle 44 is treated so as to be reusable, the cleaning water recovery tank 45 does not necessarily need to be provided independently in the single-wafer cleaning apparatus 41. For this reason, the sterilization and purification unit 14, the filtration mechanism section 15, the TOC measuring means 21, and the TOC concentration adjusting means 22 may be provided at any point in the long flow path of the water to be treated until it reaches the nozzle 44, and the single-wafer cleaning apparatus may treat the water to be treated so as to be reusable within this flow path. This makes it suitable, for example, when the water to be treated is treated as ultrapure water and this ultrapure water is used to clean a highly integrated wafer 43.

[0145] In this case, when the single-wafer cleaning equipment is in operation (during the cleaning process), ultrapure water for cleaning intermittently flows into the single-wafer cleaning equipment at the timing of cleaning the wafer 43, and this ultrapure water containing organic matter flows through the long flow path to the nozzle 44. This is approximately equivalent to the case where cleaning water containing organic matter is stored in the above-mentioned cleaning water recovery tank 45 when the long flow path to the nozzle 44 is used as a cleaning water recovery tank.

[0146] In addition, ultrapure water taken in from outside the single wafer cleaning apparatus to treat the water in the flow path so that it can be reused may also contain trace amounts of organic matter. These organic substances may adhere to the inside of pipes such as PFA tubes that form the flow paths, and may eventually be contained in the ultrapure water used as cleaning water.

[0147] For this reason, in this single-wafer cleaning equipment, it is necessary to clean not only the cleaning water after cleaning the wafer 43, but also the flow paths such as the inside of the pipes leading to the nozzle 44 to remove organic matter adhering to the inside. In this case, if the pipes are made of resin such as PFA, they are resistant to ozone, but there is a possibility that extremely small amounts of TOC may be generated, and there is a problem specific to ultrapure water that the TOC components on the pipe surface may be easily eluted, so as in the case described above, it is necessary to consider suppressing the TOC concentration when sterilizing with ozone.

[0148] For this reason, the water to be treated (ultrapure water) held in the flow path is purified by the sterilization and purification unit 14 provided in the flow path described above, and the water to be treated is passed through the single-wafer cleaning equipment for sterilization and purification treatment by the filtering mechanism 15, the TOC concentration measuring means 21, and the TOC concentration adjusting means 22. This makes it possible to supply the water to be treated from which organic matter has been removed while suppressing the TOC concentration from the nozzle 44, whether this type of single-wafer cleaning equipment is newly introduced into the cleaning process or has been in operation for a long period of time.

[0149] At this time, the water to be treated (ultrapure water) is supplied, and after ozone is added in the sterilization and purification unit 14, it flows through the long flow path described above. During this ozone addition process, the self-decomposition of ozone progresses, and some of the ozone generates OH radicals, which promote the decomposition of the eluted TOC components and organic matter attached to the inside of the piping. For this reason, by adjusting the amount of ozone generated from the sterilization and purification unit 14 in advance according to the flow rate and flow rate of the water to be treated, it is possible to leave a sufficient amount of ozone, the content of which is more likely to decrease due to self-decomposition near the secondary side of the long flow path. As a result, ozone water that maintains the residual ozone concentration throughout the entire long flow path can be flowed, and organic matter throughout the entire piping can be decomposed.

[0150] In the case of a single-wafer cleaning apparatus in which the entire flow path is a cleaning water recovery tank as described above, the degree of contamination of the flow path by the water to be treated is almost constant when the cleaning of the wafer 43 is not being maintained (when not in operation) or when this single-wafer cleaning apparatus is newly installed, so that the filtering mechanism 15 and TOC concentration measuring means 21 can be removed, ultrapure water can be replenished by the TOC concentration adjusting means 22, and the inside of the flow path can be cleaned by adjusting the ozone water concentration by the sterilization and purification unit 14 in a state where the ultrapure water is mixed with the ultrapure water remaining in the long flow path. This makes it possible to decompose organic matter in the flow path even when not cleaning the wafer 43, such as when the single-wafer cleaning apparatus is being maintained or newly installed.

[0151] In other words, the present invention is a cleaning method for a semiconductor wafer cleaning equipment using ultrapure water, in which ultrapure water is replenished by a TOC concentration adjustment means, this ultrapure water is sterilized and purified by a sterilization and purification unit, and the amount of ozone generated is adjusted in advance according to the flow rate and flow rate of the water to be treated that is supplied into the equipment so that ozone remains in the flow path piping leading to the tip nozzle, and the decomposition of organic matter in the flow path piping and the generation of extremely small amounts of TOC from the flow path piping are suppressed by the replenishment of ultrapure water and the adjustment of the ozone water concentration. In particular, when the apparatus is not in operation, it is possible to sterilize and purify the ultrapure water remaining in the piping in a mixed state with the ultrapure water being replenished.

[0152] In this case, when ultrapure water is supplied from the outside by the TOC concentration adjusting means and the water to be treated is caused to flow through the flow path to dilute the TOC concentration, for example, a drain (not shown) may be provided at an appropriate position in the flow path and the water may be discharged through this drain to the outside of the single wafer cleaning apparatus. In this case, since the water to be treated is not circulated, it becomes possible to efficiently suppress the TOC concentration to 0.01 mg / L or less, which is an index for ultrapure water, when adjusting the TOC concentration.

[0153] The sterilization and purification unit 14 may be provided inside a single-wafer cleaning apparatus. In this case, since it is provided in close proximity to the flow path, ·OH radicals generated from ozone, which is easily self-decomposed, can be effectively introduced into the flow path, and ozone water that maintains its sterilizing ability can be made to flow throughout the entire flow path.

[0154] It is known that functional water for cleaning with trace amounts of ozone added (Analytical Chemistry Overview Vol. 59 No. 5 P349-P356 (2010)) is used for this type of cleaning. However, the present invention differs from the simple use of functional water for cleaning in that the concentration of ozone water is controlled according to the flow rate and volume of the water to be treated flowing through the piping, and the addition of ozone suppresses trace amounts of TOC and TOC components dissolved in ultrapure water.

[0155] Furthermore, a case where the cleaning water treatment device of the present invention is applied to a glass substrate manufacturing apparatus will be described. Fig. 19 shows a horizontal conveying type glass substrate cleaning device 51. A glass substrate 52 is cleaned by being sprayed with pure water from a cleaning nozzle 54 while being conveyed by conveying rollers 53. The pure water used for cleaning is stored as treated water in a cleaning water recovery tank 55 provided at the bottom of the glass substrate cleaning device 51.

[0156] In the illustrated glass substrate cleaning apparatus 51 , the cleaning nozzle 54 and the transport rollers 53 constitute the cleaning processing section 11 , and the cleaning water recovery tank 55 provided at the bottom of the glass substrate cleaning apparatus 51 constitutes the cleaning water storage section 13 .

[0157] In this glass substrate cleaning apparatus 51, similarly to the plating process of FIG. 17 and the single-wafer cleaning apparatus 41 of FIG. 18, the cleaning water stored in the cleaning water recovery tank 55, which is the cleaning water storage section 13, is sterilized and purified while circulating between the sterilization and purification unit 14, and is also filtered while circulating between the cleaning water recovery tank 55 and the filtration mechanism section 15. Furthermore, depending on the ozone water concentration and TOC concentration of the water to be treated, the TOC concentration is controlled by supplying pure water to the water to be treated by the TOC concentration adjustment means 22, or draining the water to be treated and supplying pure water, so that the cleaning water in the cleaning water recovery tank 55 is maintained reusable as pure water that satisfies water quality requirements.

[0158] As described above, according to the cleaning water treatment device and cleaning water treatment method of the present invention, the pure water used to wash the parts to be washed in the cleaning processing section is subjected to sterilization and purification treatment and filtration treatment to keep bacteria and organic matter at low levels, and the TOC concentration is suppressed to a predetermined concentration or lower. Therefore, the two opposing functions of sterilization and filtration of the reused cleaning water and elution of TOC from the filter housing, etc. are achieved at the same time, and the cleaning water can be reused as water that meets the water quality requirements for pure water.

[0159] In addition, since the water to be treated that is returned to the cleaning treatment section contains a low concentration of ozone, it is possible to prevent the proliferation of bacteria in the cleaning treatment section and the cleaning water treatment device, lengthen the interval between cleaning of the cleaning treatment section and replacement of the pure water, and extend the life of the filtration filters and ion exchange resins in the cleaning water treatment device. This makes it possible to improve the operating rate of a manufacturing device that uses the cleaning water treatment device and cleaning water treatment method of the present invention, thereby reducing manufacturing costs.

[0160] In this embodiment, the arithmetic expressions and data tables which are the digitalized versions of the findings from the above experiments are based on the assumption that a resin filter housing or a resin cylinder is used, i.e., the conditions are such that TOC is most likely to leach out. Therefore, for example, if the filter housing is made of stainless steel or the cylinder is made of stainless steel, the TOC concentration will be lower than the actual concentration, and so these arithmetic expressions and data tables can be used.

[0161] The relationship between the ozone water concentration and the TOC concentration used in the arithmetic equation and the data table may be experimentally obtained (so-called on-site calibration) using a cleaning water treatment device that is actually used on-site to clean semiconductor wafer substrates, liquid crystal glass substrates, glass substrates, plated electronic components, etc.

[0162] The TOC concentration adjustment means 22 may be provided anywhere within the circulation flow path 20, but it is preferable to provide it at the downstream side of the filtration mechanism section 15, since this will result in the lowest TOC concentration in the cleaning water before the cleaning process.

[0163] In addition, in this embodiment, the cleaning water treatment apparatus and method are mainly described in which the water to be treated is pure water, but the method can also be applied to the water to be treated being 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 discharge 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 below the reference value depending on the concentration of ozone water used in the cleaning water treatment apparatus, cleaning water with a satisfactory water quality can be provided without wasting pure water or ultrapure water. [Explanation of symbols]

[0164] 11 Cleaning Processing Section 12 Washing water treatment equipment 13 Cleaning water storage section 14. Sterilization and purification unit (sterilization and water purification treatment equipment) 15 Filtration mechanism section 16 Control device 17 Inlet Channel 18 Outlet Channel 19 Filtration channel 20 Circulation flow path 22 TOC concentration adjustment means 26 Filtration device 27 Ion exchange resin

Claims

1. a cleaning water tank for storing water to be treated after cleaning with pure water for cleaning semiconductor elements, liquid crystal glass, or electronic components in a manufacturing process; A filtering mechanism unit including a filter for filtering the water to be treated in the cleaning water tank and an ion exchange resin; a circulation flow path through which the water to be treated circulates, the circulation flow path being configured to connect the filtration mechanism unit and the cleaning water tank and capable of circulating the entire cleaning treatment device; an ozone water supply means for supplying sterilizing ozone water to the filtration mechanism through the cleaning water tank and the water flow passage; a TOC concentration measuring means provided on the circulation flow path for measuring a TOC concentration in the water to be treated generated at least from the cleaning water tank or each part constituting the filtration mechanism; a TOC concentration adjusting means provided upstream of the cleaning water tank in the circulating direction of the circulation flow path, for discharging the water to be treated and supplying pure water; a control means for determining a discharge amount of the water to be treated and a supply amount of the pure water in accordance with a TOC concentration in the water to be treated, The control means controls the TOC concentration of the cleaning water to be used to a predetermined control value or lower in the pure water by draining the treated water and supplying the pure water using the TOC concentration adjustment means in accordance with the TOC concentration in the treated water, thereby controlling the treated water so that it can be used for cleaning the cleaning water tank.

2. 2. The cleaning water treatment device for semiconductor elements, liquid crystal glass or electronic components as described in claim 1, wherein the treated water after cleaning is sterilized with ozone when the pure water cleaning is performed using ultrapure water, and the control means controls the TOC concentration adjustment means to drain the treated water and supply pure water so that the treated water can be used for cleaning the cleaning water tank.

3. 3. A cleaning water treatment device for semiconductor elements, liquid crystal glass or electronic components as described in claim 1 or 2, wherein the control means uses a memory unit storing an arithmetic formula or a data table to determine the discharge amount of the water to be treated and the supply amount of the pure water according to the TOC concentration in the water to be treated.

4. a cleaning water tank for storing water to be treated after cleaning with pure water for cleaning semiconductor elements, liquid crystal glass, or electronic components in a manufacturing process; A filtering mechanism unit including a filter for filtering the water to be treated in the cleaning water tank and an ion exchange resin; a circulation process of a circulation system having a water flow passage connecting the rear stage of the filtration mechanism unit and the cleaning water tank, and a TOC concentration adjustment means provided in front of the cleaning water tank in the water flow direction of the water flow passage, the circulation system connecting the filtration mechanism unit and the cleaning water tank to configure the entire cleaning water treatment device to be circulated endlessly; an ozone supplying step of supplying sterilizing ozone water to the cleaning water tank; a TOC concentration measuring step of measuring a TOC concentration of the water to be treated flowing through the circulation flow path; a control step of determining and controlling a discharge amount of the water to be treated and a supply amount of pure water in accordance with a TOC concentration in the water to be treated, The TOC concentration adjusting means is an adjusting means for reducing the TOC concentration of the water to be treated generated at least from each part constituting the cleaning water tank or the filtration mechanism by discharging the water to be treated and supplying the pure water, A method for treating cleaning water for semiconductor elements, liquid crystal glass, or electronic components, characterized in that the TOC concentration of the cleaning water to be used is controlled to a predetermined control value or less in pure water before the cleaning water tank by discharging the water to be treated and supplying the pure water in accordance with the TOC concentration in the water to be treated using the TOC concentration adjustment means, thereby making the cleaning water usable for cleaning.

5. 5. The method for treating cleaning water for semiconductor elements, liquid crystal glass or electronic components as described in claim 4, wherein the treated water after cleaning is sterilized with ozone when the pure water cleaning is performed using ultrapure water, and the control step is performed such that the TOC concentration adjustment means drains the treated water and supplies pure water, thereby controlling the treated water to be usable for cleaning the cleaning water tank.

6. 6. A method for treating cleaning water for semiconductor elements, liquid crystal glass or electronic components as described in claim 4 or 5, wherein the control process uses a memory unit storing an arithmetic formula or a data table to determine the amount of water to be treated and the amount of pure water to be supplied according to the TOC concentration in the water to be treated.

Images