JPS5932167B2 - impurity gas trap - Google Patents

Description

[Detailed description of the invention] The present invention uses pure gas (oxygen) necessary for the semiconductor industry, etc.

The present invention relates to an impurity gas trap as a gas purification device capable of obtaining a gas containing no impurities such as hydrogen.

In recent years, the need to use highly purified gases has increased in the semiconductor industry, and various efforts have been made to this end.

Among these, some semiconductor manufacturing equipment and process equipment for semiconductors containing aluminum, such as AlGaAs, are extremely averse to oxygen and moisture.

When obtaining this high-purity gas, in the case of hydrogen gas, the purity can be improved by passing it through a palladium diffusion membrane.

However, the method for highly purifying inert gases such as nitrogen and argon has been to pass these gases through molecular sheets to adsorb oxygen, hydrogen, etc., but there are no suitable means for further purification. There wasn't.

An object of the present invention is to provide an impurity gas trap that allows high purity gas to be easily obtained by simple means.

The impurity gas trap of the present invention includes an airtight container having a connection port connected to a high vacuum evacuation means, an inlet and an outlet for the gas to be purified, and a valve provided at these inlets and outlets, and an airtight container disposed inside the airtight container. The device includes a heater capable of heating, and solid aluminum provided in contact with the heater.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

In the figure, 1, 2, and 3 are valves, and 4 is a high melting point substance (
5 is a solid aluminum piece, 6 is a molecular beam, and 7 is an airtight container.

The gas to be purified is introduced into the airtight container 7 through the valve 1.

This vessel 7 is provided with an outlet for the purified gas via a valve 2.

By closing these valves 1 and 2, the container 7
The inside of the container 7 can be evacuated through the valve 3 by a high vacuum pump.

After the inside of this container 7 is evacuated to a high vacuum, the heater 4 is heated, and the solid aluminum piece 5 placed in contact with this heater 4 is melted.

The aluminum melted in the vacuum container γ becomes molecular beams 6, scatters, and adheres to the inner wall surface of the container 7.

After a series of these operations, the temperature of the heater 7 is lowered, and when the temperature of the container has dropped, the valve 1 is opened and the gas to be purified is introduced.

Furthermore, the valve 2 is opened to allow the purified gas to flow out to a required location.

The principle by which the gas introduced from the valve 1 is purified by this device is as follows.

Ordinary solid aluminum becomes alumina through chemical adsorption of oxygen molecules, water molecules, etc. present in the atmosphere, and is covered with an alumina film.

However, since the aluminum deposited on the inner wall of the container γ of this device was deposited in a high vacuum, the surface remained clean.

In general, aluminum metal has an extremely high adsorption capacity for oxygen, moisture, etc., so when these impurity gases enter the device, a large It is possible to fix these impurity gases to the inner wall of the container of the present device with the adsorption ability.

Since the chemical reaction energy between oxygen or moisture and aluminum is extremely large, the adsorbed oxygen or moisture can be fixed to the inner wall of the container with a strong force.

Therefore, according to the present device, it is possible to selectively fix impurity gas such as oxygen or moisture to the inner wall of the container and improve the purity of hydrogen, nitrogen, or inert gas.

In addition, when the surface of the inner wall of the container is covered with impurity gas adsorption and its ability as a trap is reduced, the valves at the inlet and outlet of the container are closed, the inside of the container is evacuated, the aluminum is melted again by the heater, and the inner wall of the container is The function as a trap can be restored by scattering and adhering the aluminum to form an atomically clean aluminum film.

FIG. 2 is a block diagram of a second embodiment of the present invention.

In FIG. 2, the same numbers as in FIG. 1 indicate the same components as in FIG. 1, and the numbers with a dash indicate the same types of components as the numbers without a dash.

In Figure 1, the passage of the gas to be purified must be temporarily interrupted when the inner wall of the container is regenerated, that is, when the atomically clean surface of the aluminum is formed. , it is often desirable to use it continuously.

Therefore, in Fig. 2, the purified gas can be used continuously, and functionally it has a symmetrical structure, so that when the upper half is used, the lower half advances the regeneration process. By regenerating the upper half when the lower half is used, it is possible to continuously obtain purified gas from the gas entering from the inlet 8 at the outlet 9.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention, and FIG. 2 is a block diagram of a second embodiment of the present invention. In the figure, 1, 1'... Inlet valve, 2, 2
'...Outlet valve, 3,3'...Valve for vacuum exhaust system, 4,4'...Heater, 5,5'...Solid Aluminum piece, 6,6
'...Aluminum molecular beam, 7. γ'...
...Vacuum container, 8...Inlet, 9...Outlet.

Claims (1)

[Claims] 1. An airtight container having a connection port connected to a high vacuum evacuation means, an inlet and an outlet for the gas to be purified, and valves provided at these inlets and outlets, and a heater that can be heated inside the airtight container; an impurity gas trap comprising a solid aluminum piece in contact with the heater;