JPH0669174A - Device for heating and supplying ultra pure water - Google Patents

Abstract

PURPOSE:To prevent a device for heating ultra pure water from being damaged, improve exudation resistance in the ultra pure water, and prevent a high- temperature ultra pure water from reverse flowing by cleaning the entire part or one part of a member in contact with the ultra pure water and the high- temperature ultra pure water and then using a stainless steel which has a passive state coating on the surface. CONSTITUTION:An ultra pure water heater 2, high-temperature ultra pure water storage and supply tanks 3 and 4, and pipings b, c, and d consist of stainless steel. Further, a heat-treated passive state coating after the stainless steel is cleaned by electrolytic polishing or a colored oxide film heat-treated in an oxidation atmosphere after the electrolytic polishing is formed on the surface in contact with the ultra pure water or high-temperature pure water, thus preventing ions and organic matters from being exuded and mixed easily and preventing the high-temperature pure water from reverse flowing into the piping between the ultra pure water heater and an ultra pure water manufacturing device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for heating and supplying ultrapure water, and more specifically, for heating ultrapure water (high-purity water) for electronic industry such as semiconductor industry, pharmaceutical manufacturing, food industry, etc. TECHNICAL FIELD The present invention relates to an ultrapure water heating and supplying device which makes high temperature ultrapure water required in a field and supplies it to a point of use.

[0002]

2. Description of the Related Art In the technical field such as electronics industry, high temperature ultrapure water obtained by heating ultrapure water is used. For example, in the cleaning process of semiconductor manufacturing, in order to improve the cleaning effect on organic substances, etc., and to improve the efficiency of the drying process by spin drying or hot air after cleaning, as a cleaning liquid, a high temperature superheated at 80 to 90 ° C is used. Pure water is used. This ultrapure water is extremely high in purity and is required to have a water quality such that a minute amount of impurity ions cannot be mixed and dissolved.

An apparatus used for heating and supplying the ultrapure water to the point of use is an ultrapure water heating and supplying apparatus. This device is an ultrapure water heating device that heats ultrapure water between the ultrapure water production device and the ultrapure water use point, and stores the high temperature ultrapure water heated by the heating device and stores the ultrapure water. It is provided by connecting a high temperature ultrapure water storage / supply tank that supplies water to a use point with a pipe.

Ultrapure water contains very little or no dissolved substances and has a very strong dissolving power. In particular, high temperature ultrapure water has a very strong dissolving power, and for example, 90 ° C high temperature ultrapure water has about 10 times the room temperature.
It doubles. Therefore, if a normal metal material such as stainless steel is used as the constituent material of the ultrapure water heating and supplying device,
Ions such as metal ions are eluted and mixed in a portion in contact with the ultrapure water and the high temperature ultrapure water (contact portion), which causes a problem that the water quality of the ultrapure water deteriorates. Therefore, in order to limit the elution and mixing of ions to a very small amount, quartz glass is used as the constituent material of the ultrapure water heating device of the ultrapure water heating supply device, and quartz glass or fluororesin lining is used as the constituent material of the high temperature ultrapure water storage supply tank. A synthetic resin such as a fluororesin, which has excellent heat resistance and elution resistance, is used as a constituent material such as a material and a pipe.

A plurality of high temperature ultrapure water storage / supply tanks are usually installed. This is because by alternately using these tanks, a constant flow rate of ultrapure water is loaded on the heater of the ultrapure water heating device to absorb flow rate fluctuations due to intermittent use at the ultrapure water use point, and This is to reduce fluctuations in heat load.

The supply from the high-temperature ultrapure water storage / supply tank to the ultrapure water use point is performed by pressurizing the high temperature ultrapure water in this tank with a gas such as high-purity nitrogen gas, and then from the supply pipe to the use point. It is performed by a method of extruding high temperature ultrapure water.

[0007]

However, in the above-mentioned conventional ultrapure water heating / supplying device, the ultrapure water heating device is made of quartz glass, and quartz glass has a lower strength than metal. However, there is a problem in that it may be destroyed by pressure fluctuation, mechanical shock, thermal gradient or thermal shock. This destruction not only causes the ultrapure water heating device to stop functioning,
Since high-temperature ultrapure water will scatter and damage people and parts using synthetic resin in the vicinity, it is desired to establish a reliable preventive measure against such damage.

Further, the above quartz glass has a problem that the elution resistance is not sufficient in high temperature ultrapure water, and a slight amount of Si ions elute and mix. Further, there is a drawback that only a small device can be manufactured, and it is difficult to increase the size of the device.

On the other hand, in the high-temperature ultrapure water storage / supply tank, when quartz glass is used as the constituent material, there are problems that the same elution of ions as described above occurs and that it is difficult to increase the size of the tank. is there. When a fluororesin lining material is used, there is a problem that organic substances, fluorine and the like are eluted and mixed.

Since a fluororesin is used as a constituent material of the pipes and the like, there is a problem that organic substances, fluorine and the like are eluted and mixed.

Further, when the high temperature ultrapure water in the high temperature ultrapure water storage / supply tank is pressurized with gas and supplied to the point of use, the pressing force is transmitted to the ultrapure water heating device and the high temperature ultrapure water flows backward. The high temperature ultrapure water may damage the resin pipe between the ultrapure water heating device and the ultrapure water producing device.

The present invention has been made in view of such circumstances, and an object thereof is to solve the problems of the above-mentioned conventional ones and to prevent the destruction of the ultrapure water heating device. To improve elution resistance in ultrapure water and high temperature ultrapure water so that elution and mixing of ions and organic substances do not easily occur, and to increase the size of the ultrapure water heating device and high temperature ultrapure water storage and supply tank Further, it is an object of the present invention to provide an ultrapure water heating supply device capable of preventing backflow of high temperature ultrapure water into the pipe between the ultrapure water heating device and the ultrapure water production device.

[0013]

In order to achieve the above object, the ultrapure water heating / supplying device according to the present invention has the following structure. That is, in the ultrapure water heating and supplying device according to claim 1, between the ultrapure water producing device and the ultrapure water use point,
An ultrapure water heating device for heating ultrapure water and a high temperature ultrapure water storage supply tank for storing the high temperature ultrapure water heated by the heating device and supplying it to the ultrapure water use point are provided by pipe connection. In the ultrapure water heating / supplying device, all or part of the ultrapure water heating device, the high temperature ultrapure water storage / supply tank, and the members in contact with the ultrapure water and the high temperature ultrapure water are heated after being cleaned. It is an ultrapure water heating and feeding device characterized in that it is made of stainless steel having a passivated film formed on the surface thereof.

In the apparatus for heating and supplying ultrapure water according to claim 2, the passivation film is a colored oxide film formed by cleaning the stainless steel surface by electrolytic polishing and then heat-treating it in an oxidizing atmosphere. The apparatus for heating and supplying ultrapure water according to claim 1. In the apparatus for heating and supplying ultrapure water according to claim 3, the passivation film is a colored oxide film formed by subjecting a stainless steel surface to electrolytic polishing treatment and then heat treatment in an oxidizing atmosphere,
The apparatus for heating and supplying ultrapure water according to claim 1, wherein the colored oxide film is further dissolved and removed.

The ultrapure water heating / supplying device according to claim 4 measures the temperature of the ultrapure water at the ultrapure water inlet of the ultrapure water heating device, and based on the temperature of the ultrapure water. The ultrapure water heating / supplying device according to claim 1, further comprising ultrapure water reverse flow preventing means for closing a shutoff valve provided between the heating device and the ultrapure water producing device.

[0016]

As described above, the ultrapure water heating and supply device according to the present invention includes all or one of the members of the ultrapure water heating device, the high temperature ultrapure water storage and supply tank, and the pipes in contact with the ultrapure water and the high temperature ultrapure water. The part is made of stainless steel having a passivation film on its surface, which has been subjected to a heat treatment after a cleaning treatment.

Stainless steel having such a passivation film on the surface is more excellent in elution resistance than ordinary stainless steel having a surface on which a natural oxide film is formed, and has a metal property even in ultrapure water and high temperature ultrapure water. Ions are less likely to be eluted and mixed, and organic substances are not eluted. Further, it has excellent elution resistance as compared with quartz glass. Therefore, by using the stainless steel having such high elution resistance in the ultrapure water heating device, the high temperature ultrapure water storage supply tank and the members in contact with the ultrapure water and the high temperature ultrapure water, The elution resistance in pure water is improved, and it is difficult for elution and mixing of ions and organic substances to occur.

Further, since stainless steel is much more excellent in fracture resistance than quartz glass, by using it as a constituent material of an ultrapure water heating device, pressure fluctuation, mechanical shock, thermal gradient and thermal shock are caused. It is possible to prevent the destruction of the ultrapure water heating device due to.

Furthermore, since stainless steel is extremely excellent in workability as compared with quartz glass and a large-sized device can be easily manufactured, it is used as a constituent material of an ultrapure water heating device and a high temperature ultrapure water storage and supply tank. By using them, the size of these devices and tanks can be increased.

The temperature of the ultrapure water at the ultrapure water inlet of the ultrapure water heating device was measured, and it was provided between the ultrapure water heating device and the ultrapure water production device based on the temperature of the ultrapure water. By providing the ultrapure water backflow prevention means for closing the shutoff valve, it is possible to prevent the backflow of high temperature ultrapure water into the pipe between the ultrapure water heating device and the ultrapure water production device. That is, when the high temperature ultrapure water in the high temperature ultrapure water storage / supply tank is pressurized with gas and supplied to the use point, if a reverse flow of the high temperature ultrapure water occurs, the ultrapure water inlet of the ultrapure water heating device Since the temperature of ultrapure water rises,
By detecting this by the temperature measurement and immediately closing the shutoff valve, it is possible to prevent the high temperature ultrapure water from flowing back into the pipe between the ultrapure water heating apparatus and the ultrapure water producing apparatus.

Therefore, according to the ultrapure water heating / supplying device of the present invention, it is possible to prevent the destruction of the ultrapure water heating device and
To improve elution resistance in ultrapure water and high temperature ultrapure water so that elution and mixing of ions and organic substances do not easily occur, and to increase the size of the ultrapure water heating device and high temperature ultrapure water storage and supply tank Further, it is possible to prevent the high temperature ultrapure water from flowing back into the pipe between the ultrapure water heating device and the ultrapure water producing device.

As the passivation film on the surface of the stainless steel, if it is made of a colored oxide film formed by subjecting the surface of the stainless steel to a cleaning treatment by electrolytic polishing and then heat-treating it in an oxidizing atmosphere, it is much more ultrapure. The elution resistance in water and high temperature ultrapure water is improved, and it becomes difficult for elution and mixing of ions and organic substances to occur. Furthermore, when the above-mentioned colored oxide film is dissolved and removed, the interface layer between the colored oxide film and the lower layer base material is exposed, and this interface layer is a layer having a composition with a greater amount of Cr oxides. The dissolution property may be improved.

[0023]

EXAMPLES Examples of the present invention will be described below. FIG. 1 shows an ultrapure water heating and feeding device according to an embodiment of the present invention. This apparatus heats ultrapure water to form high temperature ultrapure water, and supplies this to the use point of semiconductor cleaning. As shown in FIG. 1, the ultrapure water heating apparatus 2 and two high temperature ultrapure water are used. The water storage supply tanks 3 and 4 are connected by pipes. The ultrapure water inlet of the ultrapure water heating device 2 has a thermometer for measuring the temperature of the ultrapure water.
Shield valve 1 which is equipped with TIA and opens and closes based on the temperature of the ultrapure water
Is provided in the middle of the pipe a. Above the tanks 3 and 4, an inert gas supply pipe d for pressurizing the high temperature ultrapure water in these tanks is connected.

The ultrapure water heating device 2, the high temperature ultrapure water storage / supply tanks 3 and 4 and the pipes b, c and d are made of stainless steel. After cleaning stainless steel by electrolytic polishing,
A passive film formed by heat treatment or a colored oxide film formed by heat treatment in an oxidizing atmosphere after electrolytic polishing is formed. The pipe a leading to the ultrapure water heating device 2 is made of trifluoride resin.

Using the above ultrapure water heating and feeding device, ultrapure water heating and feeding operation was continuously performed for a long period of time as follows. That is,
Ultrapure water at 20 ° C. was introduced into the above ultrapure water heating device 2 at a flow rate of 5 liters / minute, heated to 80 ° C., and the heated high temperature ultrapure water was supplied to the high temperature ultrapure water storage and supply tank 3 and / or No. 4, while introducing an inert gas into the high temperature ultrapure water storage / supply tanks 3 and / or 4, the high temperature ultrapure water in the tank was pressurized and intermittently supplied from the pipe c to the use point. Further, when the temperature of the ultrapure water at the ultrapure water inlet of the ultrapure water heating device 2 rises, the shutoff valve 1 is closed immediately.

As a result, the ultrapure water heating device 2 could be continuously operated for a long time without breaking. Further, elution and mixing of ions and organic substances into the ultrapure water and the high temperature ultrapure water hardly occurred, and high purity high temperature ultrapure water suitable for semiconductor cleaning could be obtained. Further, it is possible to prevent the high temperature ultrapure water from flowing back to the pipe a.
The pipe a made of fluororesin was not damaged at all.

[0027]

The ultrapure water heating / supplying device according to the present invention can prevent the destruction of the ultrapure water heating device and improve the elution resistance in ultrapure water and high temperature ultrapure water. It is difficult to cause elution and mixing of organic substances, and it is possible to increase the size of the ultrapure water heating device and the high temperature ultrapure water storage and supply tank. Furthermore, between the ultrapure water heating device and the ultrapure water production device. This has the effect of preventing backflow of high temperature ultrapure water into the pipe.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of an ultrapure water heating / supplying device according to an embodiment of the present invention.

[Explanation of symbols]

1--shielding valve, 2--ultra pure water heating device, 3, 4--high temperature ultra pure water storage supply tank, a--pipe, b, c--pipe,
d--Inert gas supply pipe.

Claims (4)

[Claims] 1. An ultrapure water heating device for heating ultrapure water between an ultrapure water producing device and an ultrapure water use point, and storing and storing high temperature ultrapure water heated by the heating device. In an ultrapure water heating / supplying device provided by pipe connection with a high temperature ultrapure water storing / supplying tank for supplying to the pure water use point, the ultrapure water heating device, the high temperature ultrapure water storing / supplying tank and the ultrapure water in the pipe An apparatus for heating and supplying ultrapure water, characterized in that all or part of the members that come into contact with high temperature ultrapure water are made of stainless steel having a passivation film formed by heating after cleaning treatment. . 2. The ultrapure water heating / supplying device according to claim 1, wherein the passivation film is a colored oxide film obtained by cleaning the surface of stainless steel by electrolytic polishing and then heat-treating it in an oxidizing atmosphere. . 3. The passivation film is a colored oxide film formed by electrolytically polishing the surface of stainless steel and then heat-treating it in an oxidizing atmosphere, and further, the colored oxide film is dissolved and removed. The apparatus for heating and supplying ultrapure water according to claim 1. 4. The temperature of ultrapure water at the ultrapure water inlet of the ultrapure water heating device is measured and provided between the ultrapure water heating device and the ultrapure water production device based on the temperature of the ultrapure water. The ultrapure water heating and supplying device according to claim 1, further comprising ultrapure water backflow prevention means for closing the shutoff valve.