JPH0852468A - Quartz glass filter - Google Patents

Abstract

PURPOSE:To reduce the generation of impurities and the propagation of bacteria and to facilitate sterilizing work by providing a filter element made of a porous quartz, a quartz glass made casing and a UV lamp to irradiate the filter element. CONSTITUTION:The filter element 1 is formed of a liquid permeable cylinder 1a made of porous quartz glass and a liquid non-permeable end plate 1b for plugging the one end, and a filter bed 1c made of the porous quartz glass is provided on the outer peripheral surface of the cylinder 1a. Moreover, the quartz glass made casing 2 is formed of a liquid non-permeable cylindrical body 2a, the liquid non-permeable end plate 2b for plugging the one end, a feed opening 2c provided on the end plate 2b and a discharge opening 2d. A protective cover 3 is mounted on the outer periphery of the casing 2 and two UV lamps 5 are arranged in the space 4 between the protective cover 3 and the casing 2. The members of the filter element 1 and the casing 2 are joined respectively by welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter used in an apparatus for purifying ultrapure water used in a semiconductor manufacturing process, and more particularly to a filter used during a refining process requiring UV irradiation for sterilization. The present invention relates to a quartz glass filter suitable for.

[0002]

2. Description of the Related Art Conventionally, ultrapure water from which impurity ions and dust have been completely removed is used in a semiconductor manufacturing process. This ultrapure water removes impurity ions with an ion exchange resin,
It is purified by filtering the dust with a resin filter. At this time, install a UV (ultraviolet) lamp in the refining line,
Microbes are sterilized by irradiating water directly with UV.
It suppresses the reproduction of fungi.

FIG. 3 shows a purification process diagram in the above-mentioned conventional ultrapure water purification apparatus. In the figure, PF is a prefilter, F1 and F2 are filters, IE1 and IE2 are ion exchange resins, U is a UV lamp, T is a pure water tank, and P is a liquid feed pump. In this ultrapure water purification device, the water from which dust in a predetermined range has been removed by the prefilter PF is once stored in the pure water tank T via the ion exchange resin IE1. Next, the pure water is further removed by the first filter F1 by the liquid feed pump P, and the pure water is sent to the second ion exchange resin IE2. In this process, the pure water is irradiated with a UV lamp and sterilized. Thereafter, the pure water passes through the second filter F2 to remove finer dust, and then part of the pure water returns to the pure water tank T and part of it is sent to the semiconductor manufacturing apparatus as ultrapure water to be used in the semiconductor manufacturing process. It

[0004]

By the way, since the filter used in the above-mentioned ultrapure water purifying apparatus is generally composed of a resin filter, it has the following technical problems. That is, an organic substance component is likely to be eluted in pure water, and this organic substance component not only serves as a source of impurity elements, but also serves as a nutrient source for fungi, which may promote the growth of fungi. Further, the resin has low durability against ultraviolet rays, and direct sterilization by ultraviolet rays is difficult. Therefore, in the ultrapure water purification process using a resin filter, there is a technical problem that cleaning and sterilization of the filter require a lot of labor, and the efficiency of the purification work is not preferable.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a quartz glass filter which is easy to sterilize with less generation of impurities and propagation of fungi.

[0006]

In order to solve the above problems, a quartz glass filter according to the present invention contains a filter element made of porous quartz glass made of porous quartz glass, and the filter element is housed and filtered. It is characterized by comprising a quartz glass casing having a supply port and a discharge port for a medium such as a gas or a liquid, and a UV lamp attached to the casing and irradiating the filter element.

[0007]

The filter element and the casing are both made of quartz glass, so that the generation of impurity elements and the elution of organic components are small, and the growth of fungi is also small. The sterilization of the filter and the sterilization of the medium passing through the filter are carried out directly through the quartz casing by UV lamps mounted on the casing when necessary.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG. Note that FIG. 1 is a side view of the filter. The filter element 1 is composed of a liquid-permeable cylinder 1a and a liquid-impermeable end plate 1b that closes one end of the cylinder 1a, and the casing 2 is a liquid-impermeable cylinder 2a.
A liquid impermeable end plate 2b for closing both ends of this cylindrical body
And a supply port 2c and a discharge port 2d provided on the end plate 2b, a protective cover 3 is attached to the outer periphery of the casing 2, and a gap 4 between the protective cover 3 and the casing 2 is formed.
Two UV lamps 5 are installed in the.

The cylindrical body 1a of the filter element 1 is a support as an asymmetric membrane filter and has a particle size of 10 to 2
30 parts by weight of water and 3 parts by weight of PVA (polyvinyl alcohol) were added to 80 parts by weight of 0 μm silica (SiO ₂ ) powder, and slip casting was performed to form a cylinder (outer diameter: 20 m).
m, inner diameter 18 mm, length 20 mm), and this molded body was fired at a temperature of 1500 ° C., which is a porous sintered body of amorphous silica powder and has a porosity of 10 to 60%.
Is.

A filter layer 1c made of the same material is provided on the outer peripheral surface of the cylindrical body 1a. The filtration layer 1c is formed by using a slurry containing silica powder having an average particle diameter of 3 μm as the cylindrical body 1a.
On the outer peripheral surface of silica gel, and after attaching silica particles, 1200 ℃
It is a fine porous layer made of a sintered body of amorphous silica powder, and has a thickness of 10 to 5 of the particle diameter.
It is 00 times.

A filter element having an asymmetric membrane structure is constituted by the filtration layer 1c composed of this fine porous layer and the porous support (cylindrical body 1a). The silica powder particles used for these elements have a purity. Is 99.9% or more, and the total amount of alkali, alkaline earth metals, heavy metals and Group BIII metal elements is preferably 150 PPM or less and is amorphous.

The cylindrical body 2a of the casing 2, the end plate 2b, the supply port 2c, the discharge port 2d, and the end plate 1b of the filter element 1 are all made of the same sintered body of amorphous silica powder as the filter element cylinder 2a. And is impermeable to liquids. It is desirable that the purity of the silica powder is 99.9% or more, and the total amount of alkali, alkaline earth metal, heavy metal, and group BIII element is 150 PPM or less.

All members of the filter element 1 and the casing 2 are adhesively bonded by welding, and no packing or the like is used.

The protective cover 3 is, for example, a metal cylindrical body, and is attached to the outer periphery of the casing 2 by welding. An ultraviolet reflection mirror is formed on the inner surface of the protective cover 3 as a reflection surface of ultraviolet rays, and the ultraviolet rays of the UV lamp 5 arranged in the gap 4 between the protective cover 3 and the casing 2 are uniformly filtered from the entire circumference side of the casing 2. Focus on element 1.

Next, Table 1 shows the results of the performance test by the ultrapure water purifying apparatus using the filter of the above embodiment. The test was performed for three months from June to August, and the viable cell count and the number of particles of 0.2 μm or more were examined. The operation was performed from 9 to 18 o'clock in the daytime and stopped at night, and the system was sterilized with hydrogen peroxide before use. Sampling was performed at the F2 exit. In the ultrapure water purification process using the filter of this embodiment shown in FIG. 2, water is not directly irradiated with UV during the water feeding process, but is irradiated with UV inside the filter. On the other hand, in the ultrapure water purification process using the filter of the comparative example (conventional resin filter) shown in FIG. 3, water is directly irradiated with UV in the water feeding process. Table 2 shows the specifications and location of each filter used in the tests of this example and the comparative example.

[0016]

[Table 1]

[0017]

[Table 2] As can be seen from Table 1, by using the filter of this embodiment equipped with a UV lamp, generation of fungi can be suppressed and high-quality ultrapure water with less dust can be obtained.

In the above embodiments, the case of using ultrapure water has been described, but the filter according to the present invention can also be used as a filter for a clean room used in the semiconductor process and the chemical industry.

[0019]

As described above, according to the present invention, since the filter element and the casing are all made of quartz glass and the UV lamp is built in, the generation of impurities and the propagation of fungi are reduced, and the sterilization work is performed. Is also very easy. As a result, working efficiency can be improved in, for example, an ultrapure water purification apparatus using this filter.

[Brief description of drawings]

FIG. 1 is a sectional view of a filter according to an embodiment of the present invention.

FIG. 2 is a purification process diagram in an ultrapure water purification apparatus using a filter according to an embodiment of the present invention.

FIG. 3 is a purification process diagram in an ultrapure water purification apparatus using a conventional filter.

[Explanation of symbols]

 1 Filter Element 2 Casing 2c Supply Port 2d Discharge Port 3 Protective Cover 5 UV Lamp

Claims (1)

[Claims] 1. A filter element made of porous quartz glass, a quartz glass casing which contains the filter element and has a supply port and a discharge port for a medium such as gas or liquid to be filtered, and the casing. A quartz glass filter, which is mounted and which illuminates the filter element.