Ultra-pure water manufacturing system, startup method thereof, and computer-readable storage medium

Abstract

The present invention relates to a warm ultrapure water manufacturing system, a starting method thereof, and a computer-readable storage medium. A starting method for a warm ultrapure water manufacturing system, the warm ultrapure water manufacturing system heating ultrapure water to a supply water temperature for supply to a use point to manufacture warm ultrapure water. In this starting method, within a water temperature range above normal temperature and below the supply water temperature, warm water obtained by heating the ultrapure water to a temperature higher than normal temperature and cooled water obtained by cooling the water temperature to a temperature lower than the warm water are alternately introduced into a warm ultrapure water pipe through which the warm ultrapure water flows.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and benefits of Japanese Patent Application No. 2021 - 177165, filed with the Japan Patent Office on October 29, 2021, the entire content of which is incorporated herein by reference. Technical field

[0003] The present disclosure relates to a method for starting a warm ultrapure water manufacturing system, a computer - readable storage medium, and a warm ultrapure water manufacturing system. Background art

[0004] As ultrapure water used in semiconductor manufacturing processes, for example, in order to improve the cleaning effect in the cleaning process, warm ultrapure water heated to a predetermined water temperature is sometimes used. Japanese Patent Laid - Open No. 2010 - 123897 describes a structure in which primary pure water is heated by an ultrapure water heating device and supplied to a use point.

[0005] In a system for manufacturing warm ultrapure water, pipes made of polyvinylidene fluoride (PVDF) are mostly used. However, when starting the warm ultrapure water manufacturing system, fluorine dissolves from the pipes made of PVDF, so that the fluorine concentration in the warm ultrapure water becomes high.

[0006] To solve this problem, Japanese Patent Laid - Open No. 2010 - 123897 describes a method for cleaning the use - point pipe by cleaning the use - point pipe with water at a water temperature higher than the water temperature of the supplied warm ultrapure water.

[0007] That is, it is described that by cleaning the use - point pipe with cleaning water at a higher water temperature, fluorine is promoted to dissolve from the use - point pipe, and after the dissolution is reduced in a short time, the desired water quality can be obtained. Summary of the invention

[0008] However, when actually starting the warm ultrapure water manufacturing system, the above - mentioned method is insufficient in terms of shortening the start - up time. Moreover, if the use - point pipe is cleaned with cleaning water at a water temperature higher than the water temperature of the supplied warm ultrapure water, it is possible to cause deformation, strength reduction, or deterioration (hereinafter, collectively referred to as "deterioration") of the use - point pipe. If the deterioration of the use - point pipe is promoted, new dissolved substances, fine particles, etc. will be generated due to the deterioration, deteriorating the water quality.

[0009] An object of the present invention is to suppress the deterioration of warm ultrapure water pipes and shorten the start - up time of the warm ultrapure water manufacturing system.

[0010] In the startup method of the warm ultrapure water production system of the first aspect, the warm ultrapure water production system heats ultrapure water to the supply water temperature for supply to the point of use to produce warm ultrapure water. In this startup method, within the water temperature range above normal temperature and below the supply water temperature, the heated water obtained by heating the ultrapure water to a temperature higher than normal temperature and the cooled water obtained by cooling the water temperature to a temperature lower than the heated water are alternately passed through the warm ultrapure water pipe for the flow of the warm ultrapure water.

[0011] That is, in the startup method of this warm ultrapure water production system, the heated water and the cooled water are alternately passed through the warm ultrapure water pipe. The heated water is ultrapure water heated to a temperature higher than normal temperature and below the supply water temperature, and the cooled water is ultrapure water cooled to a temperature lower than the heated water and above normal temperature.

[0012] Due to the passage of the heated water, the warm ultrapure water pipe slightly elongates. In contrast, due to the passage of the cooled water, the warm ultrapure water pipe slightly contracts. Therefore, the warm ultrapure water pipe expands and contracts due to the alternate passage of the heated water and the cooled water. By causing the warm ultrapure water pipe to expand and contract in this way, compared with the case of only passing the heated water and the ultrapure water at the supply water temperature, for example, the fluorine contained in the warm ultrapure water pipe can be dissolved in a short time, and the startup time of the warm ultrapure water production system can be shortened.

[0013] The water temperature range of the heated water and the cooled water is above normal temperature and below the supply water temperature for supply to the point of use. That is, it is not necessary to overheat or cool the ultrapure water.

[0014] Since the water temperature of the heated water is below the supply water temperature, compared with the case of passing high-temperature water exceeding the supply water temperature through the warm ultrapure water pipe, the deterioration of the warm ultrapure water pipe can be suppressed.

[0015] In the startup method of the warm ultrapure water production system of the second aspect, the warm ultrapure water production system includes a water temperature adjustment device for adjusting the water temperature of the ultrapure water to the supply water temperature, and the water temperature adjustment device is used to perform the heating and the cooling of the ultrapure water.

[0016] Since the water temperature adjustment device of the warm ultrapure water production system is used to heat and cool the ultrapure water, it is not necessary to use a heating device and a cooling device different from the water temperature adjustment device to control them. That is, the heating and cooling of the ultrapure water can be easily performed.

[0017] In the startup method of the warm ultrapure water production system of the third aspect, the water temperature of the heated water is 10 °C or more lower than the supply water temperature.

[0018] That is, as the heating water, since it is maintained within a certain range below and close to the supply water temperature, it can effectively play the role of elongating the temperature-controlled ultrapure water pipe. If the temperature of the heating water is lower than the water temperature that is 10°C lower than the supply water temperature (for example, when the supply water temperature is 75°C, the temperature of the heating water is less than 65°C), it may not be possible to fully elongate the temperature-controlled ultrapure water pipe. However, by making the temperature of the heating water 10°C or more lower than the supply water temperature, the temperature-controlled ultrapure water pipe can be fully elongated.

[0019] In the startup method of the temperature-controlled ultrapure water manufacturing system according to the fourth aspect, the water temperature of the cooling water is 50°C or lower.

[0020] By setting an upper limit on the water temperature of the cooling water in this way, the temperature-controlled ultrapure water pipe can be effectively contracted by the cooling water. If the water temperature of the cooling water exceeds 50°C, it may not be possible to fully contract the temperature-controlled ultrapure water pipe. However, by making the water temperature of the cooling water 50°C or lower, the temperature-controlled ultrapure water pipe can be fully contracted.

[0021] In the startup method of the temperature-controlled ultrapure water manufacturing system according to the fifth aspect, the continuous water supply time of the heating water to the temperature-controlled ultrapure water pipe each time is 3 hours or more and 24 hours or less.

[0022] By making the continuous water supply time of the heating water to the temperature-controlled ultrapure water pipe 3 hours or more each time, compared with the case where the continuous water supply time of the heating water is less than 3 hours, the temperature-controlled ultrapure water pipe can be effectively elongated by the heating water.

[0023] Moreover, by making the continuous water supply time of the heating water to the temperature-controlled ultrapure water pipe 24 hours or less each time, compared with the case where the continuous water supply time of the heating water exceeds 24 hours, the excessive elongation of the water supply time of the heating water can be inhibited.

[0024] In the startup method of the temperature-controlled ultrapure water manufacturing system according to the sixth aspect, the continuous water supply time of the cooling water to the temperature-controlled ultrapure water pipe each time is 3 hours or more and 24 hours or less.

[0025] By making the continuous water supply time of the cooling water to the temperature-controlled ultrapure water pipe 3 hours or more each time, compared with the case where the continuous water supply time of the cooling water is less than 3 hours, the temperature-controlled ultrapure water pipe can be effectively contracted by the cooling water.

[0026] Moreover, by making the continuous water supply time of the cooling water to the temperature-controlled ultrapure water pipe 24 hours or less each time, compared with the case where the continuous water supply time of the cooling water exceeds 24 hours, the excessive elongation of the water supply time of the cooling water can be inhibited.

[0027] In the startup method of the warm ultrapure water production system according to the seventh aspect, the absolute value of the water temperature change per unit time during the heating and cooling of the ultrapure water is 0.2 °C / min or more and 5.0 °C / min or less.

[0028] By making the absolute value of the water temperature change per unit time during heating and cooling 5.0 °C / min or less, the water temperature change becomes gentle. Therefore, compared with the case where the water temperature changes abruptly, deterioration of the warm ultrapure water piping can be suppressed.

[0029] In addition, by making the absolute value of the water temperature change 0.2 °C / min or more, it is possible to suppress an overly long time required for the water temperature change.

[0030] In the startup method of the warm ultrapure water production system according to the eighth aspect, the first water supply of the heated water and the first water supply of the cooled water to the warm ultrapure water piping are used as a water supply cycle, and the water supply cycle is repeated 3 times or more and 10 times or less.

[0031] By making the water supply cycle 3 times or more, fluorine can be effectively dissolved from the warm ultrapure water piping compared with the case where the water supply cycle is 2 times or less.

[0032] By making the water supply cycle 10 times or less, the startup time can be shortened without making the number of water supply cycles excessive compared with the case where the water supply cycle is 11 times or more.

[0033] In the startup method of the warm ultrapure water production system according to the ninth aspect, before supplying the warm ultrapure water from the warm ultrapure water production system to the point of use, the heated water and the cooled water are alternately supplied to the warm ultrapure water piping.

[0034] Thereby, fluorine dissolution into the warm ultrapure water supplied to the point of use can be suppressed.

[0035] In the computer-readable storage medium according to the tenth aspect, a computer program for starting up a warm ultrapure water production system is stored on the computer-readable storage medium. The warm ultrapure water production system is used to heat ultrapure water to a supply water temperature for supply to a point of use to produce warm ultrapure water. When the computer program is executed, the following steps are implemented: within a water temperature range from normal temperature or higher to the supply water temperature, heated water obtained by heating the ultrapure water to a temperature higher than normal temperature and cooled water obtained by cooling the water temperature to a temperature lower than the heated water are alternately supplied to a warm ultrapure water piping through which the warm ultrapure water flows.

[0036] That is, in a computer-readable storage medium storing instructions for starting a warm ultrapure water manufacturing system, a computer is made to execute a process of alternately passing warm-up water and cooling water through a warm ultrapure water pipe. The warm-up water is ultrapure water heated to a temperature higher than normal temperature and lower than the supply water temperature, and the cooling water is ultrapure water cooled to a temperature lower than the temperature of the warm-up water and higher than normal temperature.

[0037] Due to the passage of the warm-up water, the warm ultrapure water pipe slightly elongates. In contrast, due to the passage of the cooling water, the warm ultrapure water pipe slightly contracts. That is, the warm ultrapure water pipe expands and contracts due to the alternate passage of the warm-up water and the cooling water. By expanding and contracting the warm ultrapure water pipe in this way, compared with the case of only passing warm-up water and ultrapure water at the supply water temperature, for example, the fluorine contained in the warm ultrapure water pipe can be dissolved in a short time. And thereby, since the warm ultrapure water pipe can be made into a state where warm ultrapure water can be manufactured, the start-up time of the warm ultrapure water manufacturing system can be shortened.

[0038] The temperature ranges of the warm-up water and the cooling water are above normal temperature and below the supply water temperature supplied to the point of use. That is, it is not necessary to overheat or cool the ultrapure water excessively.

[0039] Since the temperature of the warm-up water is below the supply water temperature, deterioration of the warm ultrapure water pipe can be suppressed compared with the case of passing water at a high temperature exceeding the supply water temperature through the warm ultrapure water pipe.

[0040] In the warm ultrapure water manufacturing system according to the eleventh aspect, the warm ultrapure water manufacturing system includes: an ultrapure water manufacturing device that manufactures ultrapure water; a water temperature adjusting device that adjusts the water temperature of the ultrapure water manufactured in the ultrapure water manufacturing device and heats it to the supply water temperature supplied to the point of use to become warm ultrapure water; a warm ultrapure water pipe that is provided inside the water temperature adjusting device and between the water temperature adjusting device and the point of use, and through which the warm ultrapure water flows; and a control device that controls the water temperature adjusting device so as to alternately generate warm-up water obtained by heating the ultrapure water to a temperature higher than normal temperature and cooling water obtained by cooling the warm-up water to a temperature lower than the temperature of the warm-up water within a temperature range above normal temperature and below the supply water temperature supplied to the point of use.

[0041] In this warm ultrapure water manufacturing system, the water temperature adjusting device adjusts the water temperature of the ultrapure water manufactured by the ultrapure water manufacturing device to heat it to the supply water temperature supplied to the point of use. Moreover, the warm ultrapure water can be supplied to the point of use through the warm ultrapure water pipe.

[0042] In this warm ultrapure water manufacturing system, the control device controls the water temperature adjusting device to alternately generate warm-up water and cooling water. Warm ultrapure water pipes are provided inside the water temperature adjusting device and between the water temperature adjusting device and the point of use, and warm-up water and cooling water can be alternately introduced into the warm ultrapure water pipes.

[0043] The warm ultrapure water pipes expand and contract due to the alternate introduction of warm-up water and cooling water. Therefore, compared with the case where only warm-up water is introduced, for example, the fluorine contained in the warm ultrapure water pipes can be dissolved in a short time, and the start-up time of the warm ultrapure water manufacturing system can be shortened.

[0044] The water temperature ranges of the warm-up water and the cooling water are above normal temperature and below the supply water temperature supplied to the point of use. That is, it is not necessary to overheat or cool the ultrapure water excessively.

[0045] Since the water temperature of the warm-up water is below the supply water temperature, the deterioration of the warm ultrapure water pipes can be suppressed compared with the case where water at a high temperature exceeding the supply water temperature is introduced into the warm ultrapure water pipes.

[0046] In addition, if this warm ultrapure water manufacturing system is used, the process of manufacturing ultrapure water can be separated from the process of manufacturing warm ultrapure water from the ultrapure water. In other words, after ultrapure water that has been sufficiently purified of impurities by an ultrapure water manufacturing device is manufactured, the water temperature of the ultrapure water is adjusted by a water temperature adjusting device to obtain warm ultrapure water. In the process of manufacturing warm ultrapure water, it is only necessary to adjust the water temperature of the ultrapure water, so the process of adjusting the water temperature can be minimized. And thereby, the amount of impurities flowing into the process of adjusting the water temperature in the ultrapure water manufacturing device can be reduced, and the start-up time of the process of adjusting the water temperature can be shortened. Therefore, the damage to the warm ultrapure water pipes when starting the warm ultrapure water manufacturing system can be reduced, and high-purity warm ultrapure water can be manufactured for a long time. In particular, if the start-up method related to the technology of the present disclosure is applied to this warm ultrapure water manufacturing system, the warm ultrapure water manufacturing system can be started in a shorter time.

[0047] In the warm ultrapure water production system according to the twelfth aspect, the warm ultrapure water production system includes: an ultrapure water production device for producing ultrapure water; a water temperature adjustment device that adjusts the water temperature of the ultrapure water produced in the ultrapure water production device and raises it to the supply water temperature for supply to the point of use, thereby becoming warm ultrapure water; and a warm ultrapure water pipe that is provided inside the water temperature adjustment device and between the water temperature adjustment device and the point of use, and through which the warm ultrapure water flows; an ultrapure water pipe for directly flowing the ultrapure water from the ultrapure water production device to the point of use; and a branch pipe that branches from the ultrapure water pipe and is used for flowing the ultrapure water to the water temperature adjustment device, wherein the ultrapure water production device includes: an ion exchange device that removes foreign substances from the water to be treated through ion exchange; and a first ultrafiltration membrane that is provided downstream of the ion exchange device in the flow direction of the water to be treated, and the water temperature adjustment device includes: a heat exchanger that performs heat exchange between the ultrapure water and the heat carrier; and a second ultrafiltration membrane that is provided downstream of the heat exchanger in the flow direction of the ultrapure water.

[0048] In this warm ultrapure water production system, the water temperature adjustment device adjusts the water temperature of the ultrapure water produced by the ultrapure water production device to raise it to the supply water temperature for supply to the point of use. Moreover, the warm ultrapure water can be supplied to the point of use through the warm ultrapure water pipe.

[0049] The ultrapure water production device has an ion exchange device, and foreign substances can be effectively removed from the water to be treated through ion exchange. In addition, the ultrapure water production device has a first ultrafiltration membrane downstream of the ion exchange device in the flow direction of the water to be treated, and can remove foreign substances that cannot be removed by the ion exchange device. Thus, high-purity ultrapure water with foreign substances sufficiently removed can be obtained.

[0050] The water temperature adjustment device has a heat exchanger, and through heat exchange with the heat carrier, the water temperature of the ultrapure water can be efficiently adjusted and heated to the supply water temperature for the point of use. In addition, the water temperature adjustment device has a second ultrafiltration membrane, and even if foreign substances are generated on its upstream side, the foreign substances can be removed and the warm ultrapure water can be transported to the point of use.

[0051] In this way, a series of processes for obtaining warm ultrapure water can be achieved through a series of processes including the ion exchange device, the first ultrafiltration membrane, the heat exchanger, and the second ultrafiltration membrane.

[0052] Further, in the water temperature adjustment device, by using a heat exchanger to perform heat exchange between ultrapure water and a heat carrier, not only can warm ultrapure water heated to the supply water temperature be obtained, but also the water temperature of the ultrapure water can be made the desired water temperature. For example, within the water temperature range above normal temperature and below the supply water temperature supplied to the point of use, warmed water heated to above normal temperature and cooled water cooled to below the temperature of the warmed water can be alternately generated. Moreover, the warmed water and the cooled water can be alternately introduced into the warm ultrapure water pipe.

[0053] Since the warm ultrapure water pipe expands and contracts due to the alternate introduction of the warmed water and the cooled water, compared with, for example, the case where only the warmed water is introduced, the fluorine contained in the warm ultrapure water pipe can be dissolved in a short time, and the start-up time of the warm ultrapure water manufacturing system can be shortened.

[0054] The water temperature ranges of the warmed water and the cooled water are above normal temperature and below the supply water temperature supplied to the point of use. That is, it is not necessary to overheat or cool the ultrapure water excessively.

[0055] Since the water temperature of the warmed water is below the supply water temperature, compared with the case where water at a high temperature exceeding the supply water temperature is introduced into the warm ultrapure water pipe, deterioration of the warm ultrapure water pipe can be suppressed.

[0056] In addition, in this warm ultrapure water manufacturing system, as the essential elements of the water temperature adjustment device responsible for the process of manufacturing warm ultrapure water, for example, only the necessary minimum structure of a heat exchanger and a second ultrafiltration membrane can be adopted. By minimizing the structure of the water temperature adjustment device in this way, it is possible to accelerate the start-up of the warm ultrapure water manufacturing system and continuously supply high-purity warm ultrapure water, which is preferable.

[0057] Advantages of the Invention

[0058] In the present disclosure, deterioration of the warm ultrapure water pipe can be suppressed, and the start-up time of the warm ultrapure water manufacturing system can be shortened. Brief Description of the Drawings

[0059] Exemplary embodiments of the present disclosure will be described in detail based on the following drawings, where:

[0060] Figure 1 is a structural diagram of a warm ultrapure water manufacturing system according to a first embodiment.

[0061] Figure 2 is a structural diagram showing a part of the warm ultrapure water manufacturing system according to the first embodiment.

[0062] Figure 3 is a structural diagram showing a computer of a control device constituting the warm ultrapure water manufacturing system according to the first embodiment.

[0063] Figure 4 is a graph showing the time change when warm water and cooled water are introduced into the warm ultrapure water production system of the first embodiment.

[0064] Figure 5 is a graph showing the relationship between the number of days elapsed since startup and the fluoride ion concentration in the warm ultrapure water production system of the first embodiment. Detailed Embodiment

[0065] Hereinafter, the warm ultrapure water production system 12 according to the first embodiment will be described with reference to the accompanying drawings.

[0066] The warm ultrapure water production system 12 of the first embodiment includes a pretreatment device 14, a primary pure water device 16, a pure water tank 18, a secondary pure water device 20, a water temperature adjustment device 22, and a point of use 24.

[0067] Raw water is supplied to the pretreatment device 14. Examples of the raw water include industrial water, tap water, groundwater, river water, etc.

[0068] In the pretreatment device 14, treatment such as turbidity removal is performed to obtain pretreatment water in which a part of the suspended substances and organic substances in the raw water are removed. In addition, depending on the quality of the raw water, the pretreatment device 14 may be omitted.

[0069] In the primary pure water device 16, adsorbents such as activated carbon are used to adsorb the particles remaining in the pretreatment water, and membrane filtration devices such as reverse osmosis membrane devices are used to remove inorganic ions, organic substances, fine particles, etc. In addition, the primary pure water device 16 may include an ion exchange device and an ultraviolet irradiation device. The ion exchange device removes the remaining ions, etc. from the pretreatment water. The primary pure water device 16 can also remove dissolved gases such as dissolved oxygen from the pretreatment water by using a membrane degassing device.

[0070] The positions of the various devices in the primary pure water device 16, that is, the order in the flow direction of the pretreatment water, are set to be suitable for the order of each treatment, and are not limited to a specific order.

[0071] The primary pure water device 16 is a device that further purifies the pretreatment water treated in the pretreatment device 14 as needed to remove impurities and obtain primary pure water.

[0072] The primary pure water obtained in the primary pure water device 16 is transported to the pure water tank 18. The pure water tank 18 is a container for temporarily storing the primary pure water obtained in the primary pure water device 16.

[0073] The primary pure water stored in the pure water tank 18 is transported to the secondary pure water device 20. <U+

[0074] As Figure 2As shown, the secondary pure water device 20 of the first embodiment has a cooler 26, an ultraviolet oxidation device 28, a catalyst resin 30, a membrane degassing device 32, a non-regenerative ion exchange resin 34 and a first ultrafiltration membrane 36, which are arranged in sequence according to the flow direction of the transported primary pure water (treated water).

[0075] The cooler 26 is a heat exchanger that exchanges heat between the primary pure water and a refrigerant (e.g., cold water) supplied from a refrigerant source (not shown) to cool the primary pure water. For example, the temperature of the primary pure water is lowered from 25°C to approximately 23°C.

[0076] The ultraviolet oxidizing device 28 irradiates the primary pure water with ultraviolet rays to decompose organic matter contained in the primary pure water, thereby reducing the amount of total organic carbon (TOC) in the primary pure water.

[0077] Hydrogen peroxide is generated in the primary pure water by ultraviolet irradiation from the ultraviolet oxidizing device 28. This hydrogen peroxide is decomposed by the catalyst in the catalyst resin 30. Specifically, the reaction of H2O2→H2O+(1 / 2)O2 occurs.

[0078] In the membrane degassing device 32, gases such as dissolved oxygen present in the primary pure water are removed by the degassing membrane. Specifically, as an example, the membrane degassing device 32 is structured such that the interior of the membrane degassing device 32 is divided into a gas phase and a liquid phase by a hollow fiber membrane. Then, by flowing the primary pure water through the liquid phase and evacuating the gas phase, gases in the primary pure water pass through the hollow fiber membrane and move to the gas phase, thereby reducing the amount of gas in the primary pure water.

[0079] Furthermore, the ultraviolet oxidizing device 28 , the catalyst resin 30 , and the membrane degassing device 32 may be omitted depending on the type of ultrapure water required at the required point of use 24 .

[0080] The non-regenerative ion exchange resin 34 absorbs trace ions present in the primary pure water by exchanging ions with the primary pure water, removing them from the water. Furthermore, the non-regenerative ion exchange resin 34 is "non-regenerative," meaning it does not remove adhering ions from the ion exchange resin and regenerate the ion exchange resin. Furthermore, it can remove ions from the primary pure water at a high removal rate.

[0081] The first ultrafiltration membrane 36 removes foreign matter from the primary pure water that could not be removed on the upstream side thereof. The primary pure water passes through the secondary pure water device 20 to become secondary pure water, ie, ultrapure water, from which foreign matter has been further removed.

[0082] Ultra-pure water can be directly transported to the use point 24. The water temperature of the ultra-pure water is adjusted by the cooler 26, for example, to about 23°C. Therefore, when using ultra-pure water at this water temperature at the use point 24, the ultra-pure water is directly transported to the use point 24. In addition, in the warm ultra-pure water manufacturing system 12 of the first embodiment, it can also be transported to the water temperature adjustment device 22 for water temperature adjustment.

[0083] The water temperature adjustment device 22 has a preheater 40, a heater 42, and a second ultrafiltration membrane 44.

[0084] The preheater 40 is a heat exchanger that performs heat exchange between the ultra-pure water (water temperature about 23°C) transported from the secondary pure water device 20 and the warm ultra-pure water (water temperature about 75°C) returned from the use point 24 as described later. The preheater 40 heats the ultra-pure water as the water to be treated through this heat exchange and raises the temperature of the ultra-pure water. For example, the water temperature of the ultra-pure water can be raised to about 60°C - 70°C by the preheater 40. As the preheater 40, for example, an existing heat exchanger such as a plate heat exchanger can be used.

[0085] The heater 42 is a heat exchanger that further raises the temperature of the ultra-pure water by performing heat exchange between the ultra-pure water and a heat carrier (for example, steam supplied from a boiler) supplied from a heat source not shown. The water temperature of the heated ultra-pure water is the water temperature supplied to the use point 24, that is, the supply water temperature. In this embodiment, it is assumed that warm ultra-pure water with a water temperature of 75°C is used at the use point 24. Therefore, the water temperature of the ultra-pure water is raised to the supply water temperature of 75°C by the heater 42, thereby obtaining warm ultra-pure water. As the heater 42, for example, an existing heat exchanger such as a plate heat exchanger can be used.

[0086] In addition, in the water temperature adjustment device 22, as long as the ultra-pure water can be appropriately heated to make the water temperature within the desired range, for example, the preheater 40 and the heater 42 can also be integrated.

[0087] The second ultrafiltration membrane 44 removes foreign substances in the warm ultra-pure water that cannot be removed on its upstream side. For example, foreign substances generated in the preheater 40 and the heater 42 can be removed by the second ultrafiltration membrane 44. Thus, the warm ultra-pure water becomes a state in which foreign substances are further removed.

[0088] In particular, in this embodiment, the warm ultra-pure water or the heated water after being heated by the heater 42 is processed by the second ultrafiltration membrane 44. Therefore, as the second ultrafiltration membrane 44, an ultrafiltration membrane having a structure corresponding to the water temperature of the warm ultra-pure water is used.

[0089] In the first embodiment, the above-described elements are connected by piping 50 to enable the flow of water to the pretreatment device 14, the primary pure water device 16, the pure water tank 18, the secondary pure water device 20, and the point of use 24. In addition, the piping 50 from the secondary pure water device 20 to the point of use 24 branches on the way and is connected to the water temperature adjustment device 22, and the piping 50 also connects between the water temperature adjustment device 22 and the point of use 24. Thus, the supply of ultrapure water to the point of use 24 realizes two systems: the direct flow of the ultrapure water produced in the secondary pure water device 20 to the point of use 24 and the flow via the water temperature adjustment device 22 to the point of use 24.

[0090] The point of use 24 and the pure water tank 18 are connected by a first return piping 50A, enabling the return of the ultrapure water not used at the point of use 24 to the pure water tank 18. In addition, the point of use 24 and the preheater 40 are connected by a second return piping 50B, enabling the return of the warm ultrapure water not used at the point of use 24 to the preheater 40. In addition, the preheater 40 and the pure water tank 18 are connected by a third return piping 50C, enabling the return of the ultrapure water from the preheater 40 to the pure water tank 18.

[0091] In addition, in the preheater 40, as described above, heat exchange is performed between the ultrapure water (water temperature around 23°C) transported from the secondary pure water device 20 and the warm ultrapure water (water temperature around 75°C) returned from the point of use 24. The ultrapure water after heat exchange, for example, has a water temperature of around 28°C to 30°C, and returns to the pure water tank 18 through the third return piping 50C.

[0092] In Figure 1 and Figure 2 Among the multiple pipings 50 shown, as the material of the piping represented by a thick line, a material that dissolves fluorine when passing water is used. In particular, in this embodiment, polyvinylidene fluoride (PVDF) is used. Among them, compared with other materials, PVDF has less fluorine dissolution, less dissolution of other impurities derived from the material, and high heat resistance. Hereinafter, the piping made of polyvinylidene fluoride is particularly referred to as PVDF piping. Specifically, as Figure 2 shown, the piping 50 from the non-regenerable ion exchange resin 34 of the secondary pure water device 20 to the point of use 24 and the piping 50 that branches from this piping 50 and passes through the inside of the water temperature adjustment device 22 to the point of use 24 are PVDF pipings. In particular, the PVDF piping from the heater 42 to the point of use 24 is a piping through which warm ultrapure water passes, and is an example of the warm ultrapure water piping 50D.

[0093] In addition, the material of the piping 50 other than the PVDF piping is not particularly limited. For example, resins such as polypropylene and metals such as stainless steel can be used.

[0094] A fluoride ion concentration sensor 52 is provided on the pipe 50 (PVDF pipe) between the second ultrafiltration membrane 44 and the point of use 24. The fluoride ion concentration sensor 52 measures the fluoride ion concentration of the warm ultrapure water flowing from the second ultrafiltration membrane 44 to the point of use 24, the warm-up water and the cool-down water described later.

[0095] Figure 3 Fig. 4 shows the internal structure of a computer 54 that controls the startup of the warm ultrapure water manufacturing system 12 in the first embodiment. The computer 54 is an example of a control device that controls the water temperature adjustment device 22.

[0096] The computer 54 includes a processor 56, a memory 58, a storage 60, a display unit 62, an input unit 64, a receiving unit 66, and a communication unit 68.

[0097] A water temperature control program 70 for causing the computer 54 to function as a control device is stored in the storage 60. By expanding this control program on the memory 58 and then executing it in the processor 56, the computer 54 functions as a control device.

[0098] The display unit 62 is, for example, a display and display lights, etc. The display unit 62 displays the state of the computer 54, the states of various devices connected to the computer 54, etc.

[0099] The input unit 64 is, for example, a keyboard, a mouse, and switches, etc. The input unit 64 receives various inputs from an operator to the computer 54.

[0100] As described later, when starting up the warm ultrapure water manufacturing system 12, the receiving unit 66 receives an instruction to execute the startup method of the technology disclosed in the present application. Substantially, a part of the input unit 64 can be configured to have the function of the receiving unit 66. The display unit 62 can also be configured as a touch panel, serving as both the input unit 64 and the receiving unit 66.

[0101] In addition, in the first embodiment, the cooler 26, the preheater 40, and the heater 42 are all heat exchangers, and a water temperature sensor is provided at the outlet of the ultrapure water (including warm ultrapure water) in these heat exchangers. The data detected by the water temperature sensor is sent to the computer 54. Then, the computer 54 adjusts the water temperature by adjusting the temperature control valves of these heat exchangers.

[0102] Next, the operation of the first embodiment and the startup method of the warm ultrapure water production system 12 will be described. In addition, this "startup" means that at the stage of installing the unused warm ultrapure water production system 12 at the usage site, the state of the warm ultrapure water production system 12 is adjusted until the desired warm ultrapure water can actually be supplied to the usage point 24. In particular, in this embodiment, it means reducing the dissolution of fluoride ions from the warm ultrapure water pipe 50D (PVDF pipe from the heater 42 to the usage point 24) to a level that has no impact on the use of warm ultrapure water at the usage point 24.

[0103] Here, if only ultrapure water is passed through the PVDF pipe, the PVDF pipe contains a trace amount of fluoride as an impurity in the initial state, so the ultrapure water will contain dissolved fluoride. In particular, if warm ultrapure water is passed through the PVDF pipe, fluoride will dissolve and easily mix into the warm ultrapure water. For example, when ultrapure water is used in the semiconductor manufacturing process, if the ultrapure water contains fluoride, the yield of the semiconductor will deteriorate. Therefore, it is preferable to reduce the fluoride content in the ultrapure water used in the semiconductor manufacturing process.

[0104] In order to reduce the fluoride content of the warm ultrapure water supplied to the usage point 24, it is considered to pass warm ultrapure water through the warm ultrapure water pipe 50D when starting up the warm ultrapure water production system 12, that is, in a state where warm ultrapure water is not used at the usage point 24. That is, it is the following method: by passing warm ultrapure water through the warm ultrapure water pipe 50D, the fluoride in the warm ultrapure water pipe 50D is dissolved into the warm ultrapure water before actually using the warm ultrapure water production system 12. Here, since the passed warm ultrapure water is not used at the usage point 24, even if it contains fluoride, it will not affect the semiconductor manufacturing process.

[0105] In this way, when warm ultrapure water is passed through the warm ultrapure water pipe 50D to dissolve fluoride from the warm ultrapure water pipe 50D, if warmer warm ultrapure water is passed through, the dissolution of fluoride can be achieved in a short time, shortening the startup time. However, if warm ultrapure water with too high a temperature is passed through the warm ultrapure water pipe 50D, the deterioration of the warm ultrapure water pipe 50D will be aggravated. For example, if warm ultrapure water with a water temperature of 80°C or higher is passed through the warm ultrapure water pipe 50D, the deterioration of the warm ultrapure water pipe 50D is likely to be aggravated. Therefore, from the perspective of suppressing the deterioration of the warm ultrapure water pipe 50D, it is preferable not to increase the water temperature of the warm ultrapure water to be passed through. However, if the water temperature of the warm ultrapure water is low, the amount of fluoride dissolved per unit time will be small, and the startup of the warm ultrapure water production system 12 will take a long time.

[0106] In contrast, in the first embodiment of the technology disclosed in the present application, the warm ultrapure water production system 12 is started by the following method. In addition, before starting, for example, after the warm ultrapure water production system 12 is installed at a predetermined installation site, the ultrapure water generated in the secondary pure water device 20 is made to flow into the water temperature adjustment device 22 at normal temperature to perform sterilization treatment and cleaning inside the water temperature adjustment device 22.

[0107] Specifically, by the computer 54 executing the water temperature control program 70, the water temperature adjustment device 22 is controlled as follows. That is, through the water temperature adjustment device 22, ultrapure water obtained by heating the ultrapure water above normal temperature, i.e., heated water, and ultrapure water obtained by cooling the heated water to a temperature lower than that of the heated water, i.e., cooled water, are alternately generated. Among them, the water temperature adjustment range of the ultrapure water is above normal temperature and below the supply water temperature supplied to the use point 24. Therefore, the upper limit of the water temperature of the heated water is the supply water temperature, and the lower limit is, for example, a water temperature 10°C lower than the supply water temperature. In addition, the lower limit of the water temperature of the cooled water is normal temperature, and the upper limit is, for example, 50°C. Here, the "normal temperature" refers to the water temperature of the ultrapure water in the previous stage of water temperature adjustment by the water temperature adjustment device 22, which is 23°C in this embodiment.

[0108] Moreover, as Figure 4 shown, the heated water and the cooled water are alternately introduced into the warm ultrapure water pipe 50D. Here, one operation of introducing the heated water into the warm ultrapure water pipe 50D and the subsequent one operation of introducing the cooled water into the warm ultrapure water pipe 50D are regarded as one "water circulation". In this embodiment, this water circulation is performed multiple times. This water circulation can be repeated, for example, a preset number of times. In addition, in each water circulation, the water passing time of the heated water can be different, and similarly, the water passing time of the cooled water can also be different.

[0109] In addition, in this embodiment, the above-mentioned water circulation can also be ended based on the measured value of the fluoride ion concentration measured by the fluoride ion sensor 52. That is, the water circulation can also be ended in a state where the fluoride ion concentration measured by the fluoride ion sensor 52 is below a predetermined value, and the start of the warm ultrapure water production system 12 is substantially ended.

[0110] It is also possible to replace the detection of the fluoride ion concentration by the fluoride ion concentration sensor 52. For example, a sampling valve may be provided at this position, and the fluoride ion concentration may be measured by analyzing the sampled water offline (i.e., outside the warm ultrapure water manufacturing system 12). Whether in the case of using the fluoride ion concentration sensor 52 or in the case of offline analysis based on the sample water, it is possible to set, for example, a lower limit (e.g., 3 cycles) and an upper limit (e.g., 10 cycles) for the number of water circulation cycles. In addition, it is also possible to determine whether to continue the water circulation based on the trend of the fluoride ion concentration in each water circulation cycle. In this case, after the number of water circulation cycles reaches the upper limit or after the water circulation ends, as long as warm ultrapure water is continuously supplied to the use point 24 at the supply water temperature, the fluoride ion concentration sensor 52 is used regularly, or offline analysis based on the sampled water is performed to confirm the end of startup. In this startup method, excessive repeated heating and cooling of the ultrapure water can be suppressed, so that the deterioration of the warm ultrapure water piping can be suppressed.

[0111] The PVDF pipe slightly elongates when warm water is passed through it. In contrast, if cold water is passed through, the PVDF pipe will slightly contract. That is, the PVDF pipe expands and contracts (repeatedly elongates and contracts) due to the alternating passage of warm water and cold water. The problem with PVDF is that fluorine-containing components that are unreacted raw materials during synthesis or fluorine-containing components present in polymer defect parts detach and mix into the warm ultrapure water. In particular, the unreacted raw materials are retained inside the molecular skeleton of PVDF. In the technology disclosed in the present application, through the expansion and contraction of the PVDF pipe, the fluorine-containing components retained inside the molecular skeleton or in the gaps of the polymer structure are discharged in an extruded manner.

[0112] In contrast, even if ultrapure water with a constant water temperature is passed through the PVDF pipe, the PVDF pipe will not expand and contract even if it can only elongate or only contract. For example, if the ultrapure water passed through the warm ultrapure water pipe 50D is warm ultrapure water heated to the supply water temperature supplied to the use point 24, the PVDF pipe may elongate compared to the case where normal temperature ultrapure water is passed through. However, since warm ultrapure water with a constant water temperature is passed through, the warm ultrapure water pipe 50D will not contract. Therefore, the phenomenon that the fluorine-containing components are discharged in an extruded manner as described above does not occur.

[0113] In addition, in the technology disclosed in the present application, the material that can be used as the warm ultrapure water pipe 50D is preferably the above-mentioned PVDF, but it is not limited thereto. As long as it is a material that can withstand the supply of warm ultrapure water to the use point 24, for example, it can also be a resin such as polytetrafluoroethylene (PTFE).

[0114] In the startup method of the warm ultrapure water production system 12 of the present disclosure, by expanding and contracting the warm ultrapure water pipe 50D in this way, the amount of fluoride ions dissolved per unit time is increased compared with the case where ultrapure water with a constant water temperature is introduced into the warm ultrapure water pipe 50D. Moreover, by increasing the amount of fluoride ions dissolved per unit time from the warm ultrapure water pipe 50D, the time required to reduce the fluoride ions contained in the warm ultrapure water pipe 50D is shortened, and the startup time is shortened.

[0115] When the amount of fluoride ions dissolved from the warm ultrapure water pipe 50D is sufficiently reduced, "startup is completed". After startup is completed, warm ultrapure water adjusted to the supply water temperature at the use point 24 is supplied to the use point 24.

[0116] Figure 5 Fig. shows the relationship between the number of days elapsed since the start of the startup operation and the fluoride ion concentration measured at the use point 24 in the warm ultrapure water production system 12 of the first embodiment. Example 1 represented by a dashed line and Example 2 represented by a solid line were each subjected to a startup operation under different conditions.

[0117] Here, as an example, the benchmark for the completion of startup of the warm ultrapure water production system 12 is set to the moment when the fluoride ion concentration reaches 5 ppt. A fluoride ion concentration of 5 ppt is an example of the benchmark required in the semiconductor manufacturing process.

[0118] Here, for example, when maintaining the supply water temperature of the warm ultrapure water supplied to the use point 24 at 75°C and continuously passing water through the warm ultrapure water pipe 50D, it sometimes takes about 90 to 100 days for the fluoride ion concentration to drop to 5 ppt.

[0119] In contrast, in the technology of the present disclosure, in Example 1, the fluoride ion concentration dropped to 5 ppt in about 70 days, and in Example 2, the fluoride ion concentration dropped to 5 ppt in about 60 days.

[0120] Thus, in the technology of the present disclosure, the time required to start up the warm ultrapure water production system 12 can be shortened.

[0121] In the technology of the present disclosure, in order to obtain heated water and cooled water from the ultrapure water obtained in the secondary pure water device 20, the water temperature adjustment device 22 is used. The water temperature adjustment device 22 is a device provided in the warm ultrapure water production system 12 for heating ultrapure water to obtain warm ultrapure water. There is no need to provide a heat exchanger different from the water temperature adjustment device 22 to obtain the heated water and cooled water for obtaining warm ultrapure water, and the structure of the warm ultrapure water production system 12 can be simplified. In addition, since there is no need to control an additionally provided heat exchanger, the startup method of the warm ultrapure water production system 12 can be easily implemented.

[0122] The water temperature adjustment device 22 is separated from the secondary pure water device 20. After manufacturing ultrapure water from which impurities have been sufficiently removed by the secondary pure water device 20, the water temperature of the ultrapure water is adjusted by the water temperature adjustment device 22 to obtain warm ultrapure water. In the water temperature adjustment device 22, substantially only the water temperature of the ultrapure water needs to be adjusted, so the structure of the water temperature adjustment device 22 (and the process of adjusting the water temperature) can be minimized. As a result, the amount of impurities flowing into the water temperature adjustment device 22 (the process of adjusting the water temperature) can be reduced, and the start-up time of the process of adjusting the water temperature can be shortened. Therefore, damage to the warm ultrapure water pipe 50D at the start of the warm ultrapure water manufacturing system 12 can be reduced, and high-purity warm ultrapure water can be manufactured for a long time.

[0123] In addition, as described in the technology of the present disclosure, as the water temperature adjustment device 22, a heat exchanger (a preheater 40 and a heater 42, or a heat exchanger integrating them) and a second ultrafiltration membrane 44 are sufficient. By minimizing the structure of the water temperature adjustment device 22 in this way, the start-up of the warm ultrapure water manufacturing system 12 can be accelerated, and high-purity warm ultrapure water can be continuously supplied.

[0124] In the technology of the present disclosure, the lower limit of the water temperature of the warming water is set to a water temperature 10°C lower than the supply water temperature of the warm ultrapure water supplied to the use point 24. That is, the water temperature of the warming water is 10°C or more lower than the supply water temperature. As a result, the water temperature of the warming water is maintained within a certain range close to the supply water temperature, so the effect of stretching the warm ultrapure water pipe 50D can be effectively achieved. For example, when the supply water temperature to the use point 24 is 75°C, if the water temperature of the warming water is less than 65°C, it may not be possible to sufficiently stretch the warm ultrapure water pipe 50D. In contrast, by setting the water temperature of the warming water to 10°C or more lower than the supply water temperature (set to 65°C or more and 75°C or less in the above example), the warm ultrapure water pipe 50D can be sufficiently stretched.

[0125] In the technology of the present disclosure, when the warming water is passed through the warm ultrapure water pipe 50D, the continuous water passing time for each water passing is not particularly limited, and can be set to 3 hours or more and 24 hours or less, for example. By making the continuous water passing time of the warming water 3 hours or more, the warm ultrapure water pipe 50D can be effectively stretched by the warming water.

[0126] Moreover, by making the continuous water passing time of the warming water passed through the warm ultrapure water pipe 50D each time 24 hours or less, the excessive water passing time of the warming water can be suppressed, which helps to shorten the start-up time of the warm ultrapure water manufacturing system 12.

[0127] In addition, in the technology of the present disclosure, the upper limit of the water temperature of the cooling water is 50°C. By setting the upper limit of the water temperature of the cooling water, the warm ultra-pure water pipe 50D can be effectively contracted by the cooling water. For example, if the water temperature of the cooling water exceeds 50°C, it may not be possible to sufficiently contract the warm ultra-pure water pipe 50D. However, by setting the water temperature of the cooling water to 50°C or lower, the warm ultra-pure water pipe 50D can be sufficiently contracted. Of course, the water temperature of the cooling water is set to be maintained within this range (above room temperature and below 50°C), and is lower than the water temperature of the heating water. For example, when the supply water temperature of the warm ultra-pure water to the use point 24 is 40°C and the water temperature of the heating water is 35°C, the water temperature of the cooling water can be appropriately set according to conditions such as the supply water temperature, such as setting the water temperature of the cooling water to 30°C, etc.

[0128] In the technology of the present disclosure, when the cooling water is passed through the warm ultra-pure water pipe 50D, the continuous water supply time for each water supply is not particularly limited. For example, it can be set to 3 hours or more and 24 hours or less. By making the continuous water supply time of the cooling water 3 hours or more, the warm ultra-pure water pipe 50D can be effectively contracted by the cooling water.

[0129] Moreover, by making the continuous water supply time of the cooling water passed through the warm ultra-pure water pipe 50D each time 24 hours or less, the excessive water supply time of the cooling water can be suppressed, and it can contribute to shortening the start-up time of the warm ultra-pure water manufacturing system 12.

[0130] In the technology of the present disclosure, the water temperatures of the heating water and the cooling water are within the range of above room temperature and below the supply water temperature to the use point 24. Since the water temperature of the heating water is not too high, the deterioration caused by passing high-temperature ultra-pure water through the warm ultra-pure water pipe 50D can be suppressed. For example, if ultra-pure water at about 80°C is passed through, it may promote the deterioration of the warm ultra-pure water pipe 50D, but there is no such concern in the technology disclosed in this application.

[0131] In the technology of the present disclosure, when the ultra-pure water is heated and cooled by the water temperature adjustment device 22, the rate of change per unit time is not particularly limited. As the absolute value of the water temperature change per unit time during heating and cooling, it can be set to 0.2°C / minute or more and 5.0°C / minute or less. By setting the absolute value of the water temperature change to 5.0°C / minute or less, the water temperature change becomes gentle. Therefore, compared with the case of a sharp water temperature change, the influence on the deterioration of the warm ultra-pure water pipe 50D can be reduced.

[0132] In addition, by setting the absolute value of this water temperature change to 0.2°C / minute or more, the time required for the water temperature change from the heating water to the cooling water and from the cooling water to the heating water can be suppressed from being too long, and it can contribute to shortening the start-up time of the warm ultra-pure water manufacturing system 12.

[0133] In the technology of the present disclosure, the number of water circulation times of the warm ultrapure water pipe is set, for example, to be 3 times or more and 10 times or less. By making the water circulation 3 times or more, fluorine can be effectively dissolved from the warm ultrapure water pipe 50D compared with the case where the water circulation is 2 times or less.

[0134] In addition, by making the water circulation 10 or less, the start-up time can be shortened without making the number of water circulation times excessive compared with the case where the water circulation is 11 or more.

[0135] In the technology of the present disclosure, as a start-up method of the warm ultrapure water manufacturing system, before supplying warm ultrapure water from the warm ultrapure water manufacturing system 12 to the use point 24, an operation of alternately passing warm water and cooling water through the warm ultrapure water pipe 50D is performed. At the stage where fluorine is sufficiently dissolved from the warm ultrapure water pipe 50D, since warm ultrapure water is supplied to the use point 24, fluorine dissolution into the warm ultrapure water can be suppressed.

[0136] In the technology of the present disclosure, the warm ultrapure water manufacturing system 12 includes a non-regenerative ion exchange resin 34 (an example of an ion exchange device), a first ultrafiltration membrane 36, a heater 42 (an example of a heat exchanger), and a second ultrafiltration membrane 44. Therefore, the water to be treated sequentially passes through the non-regenerative ion exchange resin 34 (an example of an ion exchange device) and the first ultrafiltration membrane 36 in the secondary pure water device 20 to obtain ultrapure water, and this ultrapure water sequentially passes through the heater 42 and the second ultrafiltration membrane 44 to be heated to the supply water temperature supplied to the use point 24, and at the same time, warm ultrapure water with further removed impurities is obtained. Moreover, a series of continuous ultrapure water flows can be used to achieve the process of generating ultrapure water using the secondary pure water device 20 to the process of obtaining warm water and cooling water using the water temperature adjustment device 22.

Claims

1. A startup method for a warm ultrapure water manufacturing system, wherein the warm ultrapure water manufacturing system heats ultrapure water to a supply water temperature for supply to a use point to manufacture warm ultrapure water. In the startup method of the warm ultrapure water manufacturing system, within a water temperature range above normal temperature and below the supply water temperature, heated water obtained by heating the ultrapure water to a temperature higher than normal temperature and cooled water obtained by cooling to a water temperature lower than that of the heated water are alternately introduced into a warm ultrapure water pipe through which the warm ultrapure water flows. Among them, The warm ultrapure water pipe is made of polyvinylidene fluoride. Wherein, the water temperature of the heated water is above a water temperature 10°C lower than the supply water temperature, and the water temperature of the cooled water is 50°C or lower. The absolute value of the water temperature change per unit time during heating and cooling of the ultrapure water is 0.2°C / minute or more and 5.0°C / minute or less.

2. The startup method for a warm ultrapure water manufacturing system according to claim 1, wherein the warm ultrapure water manufacturing system includes a water temperature adjusting device for adjusting the water temperature of the ultrapure water to the supply water temperature. Using the water temperature adjusting device, the ultrapure water is heated and cooled.

3. The start-up method of the warm ultrapure water manufacturing system according to claim 1 or 2, wherein, The continuous water supply time for each introduction of the heated water into the warm ultrapure water pipe is 3 hours or more and 24 hours or less.

4. The startup method of the warm ultrapure water manufacturing system according to claim 1 or 2, wherein, The continuous water supply time for each introduction of the cooled water into the warm ultrapure water pipe is 3 hours or more and 24 hours or less.

5. The startup method of the warm ultrapure water manufacturing system according to claim 1 or 2, wherein, One water supply of the heated water and one water supply of the cooled water to the warm ultrapure water pipe are regarded as a water supply cycle, and the water supply cycle is repeated 3 times or more and 10 times or less.

6. The startup method of the warm ultrapure water manufacturing system according to claim 1 or 2, wherein, Before supplying the warm ultrapure water from the warm ultrapure water manufacturing system to the use point, the heated water and the cooled water are alternately supplied to the warm ultrapure water pipe.

7. A computer-readable storage medium having a computer program for starting a warm ultrapure water manufacturing system, wherein the warm ultrapure water manufacturing system is used to heat ultrapure water to a supply water temperature for supply to a use point to manufacture warm ultrapure water. When the computer program is executed, the following steps are implemented: within a water temperature range above normal temperature and below the supply water temperature, heated water obtained by heating the ultrapure water to a temperature higher than normal temperature and cooled water obtained by cooling to a water temperature lower than that of the heated water are alternately introduced into a warm ultrapure water pipe through which the warm ultrapure water flows. Among them, The warm ultrapure water pipe is made of polyvinylidene fluoride. Wherein, the water temperature of the heated water is above a water temperature 10°C lower than the supply water temperature, and the water temperature of the cooled water is 50°C or lower. The absolute value of the water temperature change per unit time during heating and cooling of the ultrapure water is 0.2°C / minute or more and 5.0°C / minute or less.

8. A warm ultrapure water manufacturing system, the warm ultrapure water manufacturing system having: an ultrapure water manufacturing device for manufacturing ultrapure water; a water temperature adjusting device for adjusting the water temperature of the ultrapure water manufactured in the ultrapure water manufacturing device and heating it to a supply water temperature for supply to a use point, thereby becoming warm ultrapure water. Warm ultrapure water pipe, the warm ultrapure water pipe is arranged inside the water temperature adjusting device and between the water temperature adjusting device and the use point, and the warm ultrapure water flows in the warm ultrapure water pipe; And A control device, the control device controls the water temperature adjusting device to alternately generate warm water obtained by heating the ultrapure water to a temperature higher than the normal temperature and cooling water obtained by cooling the water temperature to a temperature lower than the warm water within a water temperature range above the normal temperature and below the supply water temperature supplied to the use point, and alternately introduce the warm water and the cooling water into the warm ultrapure water pipe, Wherein, the warm ultrapure water pipe is made of polyvinylidene fluoride, Wherein, the water temperature of the warm water is above a water temperature 10°C lower than the supply water temperature, and the water temperature of the cooling water is 50°C or lower, The absolute value of the water temperature change per unit time during the heating and cooling of the ultrapure water is 0.2°C / minute or more and 5.0°C / minute or less.

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