JPH1190162A - Gas purifier for semiconductor plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas purifier for a semiconductor plant by which extremely fine particles and impurity ions in gaseous starting material can be removed. SOLUTION: In a gas purifier for a semiconductor plant for purifying gas used in the semiconductor plant, a gas path formed inside the purifier itself is constituted of plural unit cells 1 each consisting of a dust collecting electrode 2 and a discharge electrode 3 which are arranged in parallel. In each unit cell 1, corona discharge is generated so that extremely fine particles and impurity ions in the gas are collected on the inner peripheral surface of the dust collecting electrode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas cleaning apparatus for a semiconductor factory which can remove various impurities such as ultrafine particles and impurity ions in various gases used in a semiconductor factory and purify the various gases. It is about.

[0002]

2. Description of the Related Art Generally, in a semiconductor factory, various source gases are used in various processing steps such as a step of forming a thin film on a semiconductor wafer. Such a source gas needs to be highly purified so that impure fine particles contained therein do not adhere to a semiconductor wafer or the like to produce a defective product. Therefore, in the semiconductor factory, as shown in FIG. 4, a process gas (for example, a doping gas such as arsine) and a diluting gas (for example, a process gas diluting gas such as helium) supplied from the gas supply facilities 15 and 16 are used. ) And a nitrogen gas (used as an atmosphere gas or the like) supplied from a nitrogen manufacturing plant 17.
Before introduction into the gas purifiers 11a, 11b, 11c
And fine particles and the like in each raw material gas are removed through filters 12a, 12b and 12c.
That is, each source gas is supplied to each of the gas purifiers 11a to 11c.
And the purity of the raw material gas is increased by reacting the reactants in each of the gas purifiers 11a to 11c by chemical adsorption or the like, and then introduced into each of the filters 12a to 12c. Through which fine particles in each source gas are collected and removed.

[0003]

However, in each of the above gas purifiers 11a to 11c, the reaction material (for example, in the case of nitrogen gas, a molecular sieve or the like is used as the reaction material) in the gas purifiers 11a to 11c. Impurity ion particles (for example, ion particles made of aluminum ions or the like) mixed in the trace amount source gas cannot be removed by each of the filters 12a to 12c.
In each of the filters 12a to 12c, among the fine particles existing in the raw material gas,
It is not possible to remove ultrafine particles finer than the grain size of ~ 12c. In particular, mite hair, spores, and fibrous foreign matter (having a diameter of about 0.1 μm and a length of about 5 μm) are likely to pass through. Pass together).
For this reason, the particle size of dust which affects the yield of products (the yield and performance of semiconductor production is generally 1/10 of the minimum line width.
Is said to be unable to raise).

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a gas cleaning apparatus for a semiconductor factory which can remove ultrafine particles and impurity ions in a source gas.

[0005]

In order to achieve the above-mentioned object, a gas purifying apparatus for a semiconductor factory according to the present invention is a gas purifying apparatus for a semiconductor factory for purifying gas used in a semiconductor factory. A corona discharge device is built in a gas passage formed inside the device itself, and a small impurity in a gas is charged and collected by corona discharge of the device. Here, the gas referred to in the present invention includes:
It includes not only raw material gas directly used as raw material, but also air used for transportation and clean room cleaning. Note that the ultrafine particles include fibrous foreign matter, granular foreign matter, and the like. Further, the impurity ion particles refer to particles dispersed in the source gas in an ionic state, for example, metal ion particles.

That is, the gas purifying apparatus for a semiconductor factory according to the present invention incorporates a corona discharge device in a gas passage formed therein, and charges minute impurities in gas by corona discharge of the device. I am trying to collect it. Thus, a corona discharge is generated in the gas passage by the corona discharge device built in the gas passage (when a DC voltage of several thousand volts is applied between the two electrodes provided in the corona discharge device, the corona discharge occurs between the two electrodes). Can be generated), and the particles (including extremely fine particles) in the gas introduced into the gas passage are instantaneously charged (usually negatively charged), and the Coulomb force causes It is attracted and collected by the corresponding electrode (the electrode applied positively) of both electrodes. Further, the impurity ion particles in the gas are similarly charged, and are attracted and collected by the corresponding electrode by the Coulomb force. The most significant feature of such a small impurity trapping means using corona discharge is that it is trapped by Coulomb force, so that regardless of the size of the particles, even ultrafine particles and even impurity ion particles. The point is that it can be collected. Therefore, in the gas cleaning apparatus for a semiconductor factory of the present invention, a gas having a very high degree of cleanliness can be obtained. By supplying the gas to a semiconductor manufacturing apparatus or the like of a semiconductor factory, the gas manufactured by the semiconductor manufacturing apparatus or the like can be obtained. The yield of semiconductor products can be greatly increased. On the other hand, a corona discharge device has a plurality of unit cells each including a cylindrical conductor serving as one electrode and a thin wire conductor provided in the cylindrical conductor and serving as the other electrode, which are arranged in parallel in the gas passage. If configured
The gas passage can be manufactured with unit cells having a simple structure arranged side by side.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a source gas supply line of a semiconductor factory using a gas cleaning apparatus 5 of the present invention. In this embodiment, the gas cleaning device 5 is provided at a portion downstream of each of the filters 12a to 12c (on the semiconductor manufacturing device 18 side) in each raw material gas supply line. The other parts are the same as those of the source gas supply line shown in FIG. 4, and the same parts are denoted by the same reference numerals.

FIGS. 2 and 3 show the gas purifying apparatus 5 described above.
1 shows a unit cell 1 which is a constituent unit of a gas passage formed inside the device. This unit cell 1 is provided with a dust collecting electrode (diameter 10 mm) 2 made of a cylindrical conductor and a discharge electrode (diameter 0.1 mm) 3 made of a thin wire such as a wire. The discharge electrode 3 extends along the axis of the dust collecting electrode 2 from a position before the inlet 2 a of the source gas (such as nitrogen gas) 10 of the dust collecting electrode 2 to a position before the outlet 2 b of the source gas 10, It is fixed by fixing means (not shown).
Reference numeral 4 denotes an electric wire for applying a direct current to the dust collecting electrode 2 and the discharge electrode 3, and the dust collecting electrode 2 is positively applied.
The discharge electrode 3 is applied negatively. Such unit cells 1 are assembled in a large number in parallel, and the above-mentioned gas passage is formed. In forming such a gas passage, the space surrounded by the outer peripheral surface of each dust collecting electrode 2 is filled with a filler without any gap, so that gas cannot pass through.

In each of the unit cells 1, ultrafine particles and impurity ions in the source gas 10 can be collected as follows. That is, first, a DC current of several thousand volts (for example, 8000 volts) is applied between the two electrodes 2 and 3 to generate corona discharge in the dust collection electrode 2. Then, the raw material gas 10 is introduced into the dust collecting electrode 2. As a result, the particles in the source gas 10 are instantaneously charged, and of course, the ultrafine particles are also instantaneously charged (normally, as shown in FIG. 1, negatively charged).
Due to the Coulomb force, the dust is collected by being attracted to the inner peripheral surface of the dust collection electrode 2 which is positively applied. The source gas 10
The impurity ions therein are similarly charged, attracted to the inner peripheral surface of the dust collecting electrode 2 by the Coulomb force, and are collected. On the other hand, ultrafine particles and impurity ions positively charged by corona discharge are also collected on the outer peripheral surface of the discharge electrode 3 by Coulomb force. As described above, since the particles are collected by using the Coulomb force, it is possible to collect very small particles or impurity ions.

The gas purifying apparatus 5 having a gas passage in which a number of such unit cells 1 are arranged in parallel is a gas purifying apparatus 1.
As shown in FIG. 1, together with 1a to 11c and filters 12a to 12c, in a raw material gas supply line of a semiconductor factory, gas purifiers 11a to 11c, filters 12a to 12c, and a gas cleaning device 5 are installed in this order from the upstream side. . Each source gas 10 is supplied to each gas purifier 11a.
To the respective gas purifiers 11a to 11c to increase the purity of each raw material gas 10, and then to each of the filters 12a to 12c,
Fine particles in each source gas 10 are removed in 2a to 12c. After that, the gas was introduced into each gas cleaning device 5 and passed through the eyes of each filter 12a to 12c by corona discharge generated in each unit cell 1 while passing through each unit cell 1 of each gas cleaning device 5. Source gas 1
Ultra-fine particles and impurity ions in 0 are collected,
A very clean gas is obtained.

As described above, in this embodiment, the gas cleaning device 5 can remove ultrafine particles and impurity ions in the source gas 10. Therefore, air with a very high degree of cleanliness can be supplied to the semiconductor manufacturing equipment 18 and the like in the semiconductor factory, and the product yield in the semiconductor factory can be greatly increased.

In the above embodiment, a cylindrical conductor is used as the dust collecting electrode 2. However, the present invention is not limited to this. For example, a rectangular cylindrical conductor or a flat conductor may be used. Is also good.

[0014]

As described above, the gas cleaning apparatus for a semiconductor factory according to the present invention removes ultrafine particles and impurity ions in a gas by generating corona discharge in a gas passage. Therefore, it is possible to obtain a very clean gas. Therefore, by supplying such a highly clean gas to a semiconductor manufacturing apparatus or the like in a semiconductor factory, the yield of semiconductor products manufactured in the factory is greatly improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a source gas supply line using a gas cleaning device of the present invention.

FIG. 2 is a transverse sectional view of a unit cell constituting the gas cleaning device.

FIG. 3 is a longitudinal sectional view of the unit cell.

FIG. 4 is an explanatory view of a source gas supply line showing a conventional example.

[Explanation of symbols]

 1 unit cell 2 dust collecting electrode 3 discharge electrode

Claims (2)

[Claims] 1. A gas purifying apparatus for a semiconductor factory for purifying a gas used in a semiconductor factory, wherein a corona discharge device is built in a gas passage formed inside the gas purifier, and a corona discharge device of the gas purifier is provided. A gas purifying apparatus for a semiconductor factory, wherein minute impurities in a gas are charged and collected by discharging. 2. A corona discharge device comprising: a plurality of unit cells each including a tubular conductor serving as one electrode and a thin wire conductor provided inside the tubular conductor and serving as the other electrode; 2. The gas purifying apparatus for a semiconductor factory according to claim 1, wherein said gas purifying apparatus is arranged side by side.