JPH06134457A - Super-pure water manufacturing system and manufacturing method - Google Patents

Abstract

PURPOSE:To develop an economical super-pure water manufacturing system which is capable of supplying super-pure water stably and does not discard usable ion exchange resin. CONSTITUTION:In a super-pure water manufacturing system including an ion exchange resin device, mixed bed-type ion exchange resin devices consisting of mixed non-regeneration-type cationic exchange resin and non-regeneration-type anionic exchange resin are installed serially in two stages. Further, an ion detection device 8 is installed between the front stage mixed bed-type ion exchange resin device 5 and the back stage mixed bed-type ion exchange resin device 6. In addition, a bypass pipe 13 is additionally provided which connects an inflow pipe to the front stage ion exchange resin device to an outflow pipe from said device through a valve 12. The subject super-pure water manufacturing system is characteristic of the described components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system and a method for producing ultrapure water, and more particularly to a mixed bed type ion exchange resin device in which a non-regenerated type cation exchange resin and a non-regenerated type anion exchange resin are mixed. The present invention relates to an ultrapure water production system including the same and an ultrapure water production method using the system.

[0002]

2. Description of the Related Art Ultra pure water used as water for cleaning semiconductors is usually produced by using primary pure water as raw water. That is, a trace amount of organic substances, fine particles, contained in the primary pure water,
The role of the ultrapure water production system is to remove ions and the like to even lower concentrations. Therefore, the ultrapure water production system is provided with an ultraviolet oxidation device for removing these impurities, an ion exchange resin device, an ultrafiltration device, and the like, and each unit device is regularly maintained.

The presence of the above impurities in ultrapure water causes surface contamination during cleaning of semiconductor devices, resulting in a significant decrease in device performance. In particular, it is said that metal ions such as sodium have a large influence rate even in an extremely small amount, and it is necessary to pay close attention to maintain the performance of an ion exchange device that removes such metal ions.

As the ion exchange device in the ultrapure water production system, a so-called mixed bed type ion exchange resin device in which a non-regeneration type cation exchange resin and an anion exchange resin are mixed is employed. When the ion removal performance of the ion exchange resin device deteriorates, it is necessary to promptly update the ion exchange resin inside the device, but the device must be temporarily stopped in the normal update work. For this reason, the renewal work of the ion exchange resin is inevitably carried out when the semiconductor factory stops the work, and the usable ion exchange resin is often discarded. In addition, if you try to increase the usage rate of ion exchange resin, there is a risk that it will not be able to respond to fluctuations in water quality and the water quality will deteriorate due to breakage of ion exchange resin, and in extreme cases it will also stop the production of semiconductors. It can happen.

Therefore, in the current ultrapure water production system, a method of filling a sufficient amount of ion exchange resin and periodically updating it is adopted. In such an apparatus configuration, the usable ion-exchange resin is also discarded as described above, and thus it cannot be said to be an efficient system, and there is a problem from the viewpoint of resource saving. Furthermore, in such a configuration including only a single ion exchange device, it is easily affected by an abnormality in the primary pure water production system, and sometimes an ion break accident occurs during operation of a semiconductor factory, It cannot be said that the performance of the ultrapure water production system that supplies high-purity ultrapure water is stable.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an economical ultrapure water production system which can stably supply ultrapure water and does not discard usable ion exchange resins. To aim.

[0007]

According to the present invention, a mixed-bed type ion exchange resin device, which has conventionally been constituted by a single tank, and the resin can be renewed only when the apparatus is stopped, has a two tank structure. A configuration that detects the amount of ions between the mixed bed type ion exchange resin device in the previous stage and the mixed bed type ion exchange resin device in the subsequent stage, and updates only the ion exchange resin in the preceding stage when an ion break is detected The above object is achieved by the above.

That is, the ultrapure water production system according to the present invention is an ultrapure water production system including an ion exchange resin device, which is a mixture of a non-regenerated cation exchange resin and a non-regenerated anion exchange resin. The floor type ion exchange resin device is installed in two stages in series, and the ion detector is installed between the mixed bed type ion exchange resin device in the front stage and the mixed bed type ion exchange resin device in the rear stage, and the ion exchange resin device in the front stage is installed. It is characterized in that a bypass pipe for connecting the inflow pipe to and the outflow pipe from the device is connected via a valve.

The method for producing ultrapure water according to the present invention is
Using the above ultrapure water production system, the ion detector detects a decrease in the ion removal performance of the mixed bed type ion exchange resin device in the preceding stage, and when an ion break is detected, the mixed bed type ion exchange resin in the preceding stage is detected. Only the ion-exchange resin in the equipment is replaced with a new resin, and during that time, water is passed only to the mixed bed type ion-exchange resin equipment in the subsequent stage.

[0010]

EXAMPLES The present invention will now be described in more detail with reference to the illustrated examples, but the present invention is not limited thereto.

FIG. 1 is a schematic system diagram of an ultrapure water production system showing an embodiment of the present invention. The main equipment configuration of this system is an ultrapure water tank 2 for storing the primary pure water from the primary pure water supply system 1, an ultrapure water pump 3, an ultraviolet oxidation device 4, and a mixed bed type ion exchange resin device 5 in the preceding stage. The mixed bed type ion exchange resin device 6 and the ultrafiltration device 7 in the latter stage. In this ultrapure water production system, an ion detector 8 is installed between the mixed bed type ion exchange resin device 5 in the front stage and the mixed bed type ion exchange resin device 6 in the rear stage. Examples of the ion detector that can be used include a conductivity meter and a resistivity meter that detect the ion concentration. The produced ultrapure water is installed at the outlet of the ultrafiltration device 7 with an ion detection device such as a specific resistance meter, a fine particle meter, a TOC meter, and the like to be water quality controlled, and supplied to a use point 9 such as a semiconductor cleaning device. It

When ultrapure water is produced by the ultrapure water production system shown in FIG. 1, the liquid to be treated flowing out from the ultraviolet oxidation device 4 is a mixed bed type ion exchange resin device 5 in the front stage and a mixed bed in the rear stage. Water is passed through the ion-exchange resin device 6, where a small amount of inorganic ions remaining in the primary pure water and inorganic ions eluted from the ultrapure water production system are formed, and further formed by the ultraviolet oxidation device 4. Ionic organic matter is removed. Most of these ionic substances are removed by the mixed bed type ion exchange resin device 5 in the preceding stage, and finally the ultrafiltration device 7 removes fine particles to become ultrapure water, and the semiconductor is washed at the use point 9. Unused ultrapure water, which is used for, for example, is returned to the ultrapure water tank 2. The ultrapure water production system constantly maintains high-purity water quality by continuously repeating this water passage-impurity removal.

The mixed bed type ion exchange resin device 5 in the preceding stage gradually approaches the ion break according to the water passage time in the process of removing the ionic substances in the ultrapure water as described above. Ion detection device 8 installed between two ion exchange resin devices
Detects this ion break and displays / warns the time of renewal of the mixed bed type ion exchange resin in the previous stage. In the system of the present invention, an alarm from the ion detector 8 causes
The valves 10 and 11 are closed, the valve 12 is opened, and the water to be treated flows into the bypass pipe 13 to automatically bypass the mixed bed type ion exchange resin device 5 in the front stage and the mixed bed type ion exchange resin device in the rear stage. In step 6, the inorganic ions in the liquid to be treated are removed, and in the meanwhile, the ion exchange resin in the previous stage is renewed. Therefore, not only when the ultrapure water production system is stopped, but also when the resin needs to be updated, it can be updated at any time. Furthermore, since the ion exchange resin in the former stage can be used up to the break state, it is economical. In addition, in order to detect the breakage of the ion exchange resin in the latter stage, it is preferable to install an ion detector between the latter ion exchange resin device and the ultrafiltration device (not shown).

FIG. 2 shows the result of investigation on the ion exchange performance of the waste resin actually used in the semiconductor factory.
For the investigation, a certain amount of waste ion exchange resin (A in Fig. 2,
B and C) and virgin ion exchange resin (FIG. 2).
Permeate of the reverse osmosis device was passed through. As shown in FIG. 2, the waste ion exchange resin at the end of the update still has an ion exchange capacity of 20 to 40%, and a large amount of unused resin is discarded in the conventional regular resin update. .

The great effect of the present invention is that the resin can be renewed without stopping the ultrapure water production system. According to the results shown in FIG. 2, the production system of the present invention and the present invention are shown. By adopting the method of at least 2
The amount of resin used can be reduced by 0%, which is extremely economical. Moreover, when the conventional single structure ion exchange resin device is used, TOC (Total Or
In some cases, an ionic organic substance that is a component of ganic carbon may leak early, and the present invention is advantageous even in such an abnormal case.

Further, in a recent ultrapure water production system, an anion exchange resin for removing ionic organic substances formed by ultraviolet oxidation is installed in the subsequent stage of the ultraviolet oxidation device 4, and a mixed bed type ion exchange resin is provided in the subsequent stage. Embedding devices is becoming mainstream. When the present invention is applied to this type of system, ion exchange is performed in a three-phase configuration of the ultraviolet oxidation device 4, the anion exchange resin, and then the mixed bed type ion exchange resins in the front and rear stages.

[0017]

By using the ultrapure water production system and the ultrapure water production method according to the present invention, the ion exchange resin can be updated even when the system is in operation, and when the primary pure water supply system is in an abnormal state. , For example, properly respond to an abnormal early break of the mixed bed type ion exchange resin in the ultrapure water production system due to an increase in the leakage component of the reverse osmosis device, defective regeneration of the ion exchange resin for pure water production, etc. Is possible. In addition, the amount of ion exchange resin used can be significantly reduced as compared with the conventional regular update method.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of an ultrapure water production system showing an embodiment of the present invention.

FIG. 2 is a time-dependent change diagram of specific resistance showing ion exchange performance of an unused resin and a used waste resin.

[Explanation of symbols]

 1 Primary Pure Water Supply System 2 Ultra Pure Water Tank 3 Ultra Pure Water Pump 4 Ultraviolet Oxidation Device 5 Ion Exchange Resin Device in the First Stage 6 Ion Exchange Resin Device in the Second Stage 7 Ultrafiltration Device 8 Ion Detector 9 Use Point 13 Bypass Pipe

Claims (3)

[Claims] 1. In an ultrapure water production system including an ion exchange resin device, a mixed bed type ion exchange resin device in which a non-regeneration type cation exchange resin and a non-regeneration type anion exchange resin are mixed is provided in two stages in series. Installed, installed an ion detector between the mixed bed type ion exchange resin device in the front stage and the mixed bed type ion exchange resin device in the rear stage, and an inflow pipe to the ion exchange resin device in the front stage and an outflow pipe from the device. A system for producing ultrapure water, characterized in that a bypass pipe is connected to connect with and via a valve. 2. The ultrapure water production system according to claim 1, wherein the ion detector is a conductivity meter or a resistivity meter for detecting the amount of ions. 3. The apparatus according to claim 1, wherein the ion detector detects a decrease in the ion removal performance of the mixed bed type ion exchange resin device in the preceding stage, and when the ion break is detected, the mixing in the preceding stage is detected. A method for producing ultrapure water, characterized in that only the ion-exchange resin in the bed-type ion-exchange resin device is replaced with a new resin, and during that period, water is passed only through the mixed-bed-type ion-exchange resin device in the subsequent stage.