JPH0888183A - Purge method of residual reaction gas - Google Patents

Abstract

PURPOSE: To reduce the equipment cost and the occupied area, and improve the utilization of substitution gas. CONSTITUTION: In a method wherein residual reaction gas left in piping connected with a vessel valve of a reaction gas cylinder and the reaction gas cylinder is purged by using inert gas at the time of switching the reaction gas cylinder, a purge system 7 constituted of one purge vessel 6 which is connected with an inert gas piping system 5 and filled with inert gas is used in common with a plurality of reaction gas cylinders 11 , 12 wherein the respective gas cylinders are connected with the respective reaction systems 21 , 22 and the respective discharging systems 41 , 42 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purging residual reaction gas, and more particularly to a reaction gas or impurity gas for growth in a vapor phase growth process or a liquid phase growth process, or
The present invention relates to a purging method for replacing a residual reaction gas remaining inside a pipe with an inert gas when replacing a container (cylinder) containing a reaction gas such as an etching gas in a dry etching process.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing a semiconductor device,
When switching a used reaction gas cylinder to a new gas cylinder, it is necessary to replace the residual reaction gas inside the piping and container valve opening with a harmless gas and then replace it. It was equipped with a gas cylinder.

FIG. 4 is a conceptual configuration diagram for explaining such a conventional residual reaction gas purging system, in which a reaction gas from a reaction gas cylinder 1 containing a reaction gas is reacted through a pipe and a valve. In the semiconductor manufacturing system that is fed into the system 2, a replacement gas cylinder 3 in which a replacement gas composed of a harmless inert gas such as nitrogen gas is sealed for each reaction gas is installed.

When the reaction gas in the reaction gas cylinder 1 is used up and switched to a new reaction gas cylinder, the container main valve of the replacement gas cylinder 3 and the valve ₂ are opened with the valve ₁ closed to replace the replacement gas such as nitrogen gas. The reaction gas remaining in the pipe and the container valve opening was discharged from the exhaust system 4 together with the replacement gas by sending the reaction gas into the piping and the container valve opening and opening the valve ₃ .

[0005]

However, in the conventional residual reaction gas purging system, there is a drawback in that the equipment cost becomes expensive because a dedicated replacement gas cylinder is required for each reaction gas, and the reaction gas cylinder is not used. Since the replacement gas cylinder was also stored in the gas box to be stored, there is a drawback that the gas box cannot be made small, that is, it occupies a large area. Since the quality guarantee period is set, there is a drawback that the amount of unused replacement gas that cannot be consumed is increased.

Therefore, it is an object of the present invention to reduce the facility cost, occupy a small area, and improve the use efficiency of the replacement gas.

[0007]

FIG. 1 is an explanatory view of the principle structure of the residual reaction gas purge system of the present invention, and the means for solving the problems of the present invention will be described with reference to FIG. In FIG. 1, but not only two reaction gas cylinder 1 ₁ and 1 ₂ shown, actually those having a plurality of reaction gas cylinder according to the type of the reaction gas required in the manufacturing process of a semiconductor device is there.

Referring to FIG. 1, the present invention relates to a method of purging a residual reaction gas remaining inside a container valve opening of a reaction gas cylinder and a pipe connected to the reaction gas cylinder with an inert gas when switching the reaction gas cylinder, respectively. Are the individual reaction systems 2 ₁ , 2 ₂ ·
.. And, for the plurality of reaction gas cylinders 1 ₁ , 1 ₂ ... Connected to the individual exhaust systems 4 ₁ , 4 ₂ ... Inert gas connected to the pipe inert gas system 5 It is characterized in that a purge system 7 composed of one purge container 6 for filling is used in common. The pipe inert gas system refers to an inert gas source such as nitrogen gas, which is piped in the factory.

Further, according to the present invention, before the purge container 6 is filled with the inert gas from the pipe inert gas system 5, the gas remaining in the purge container 6 is exhausted by using a vacuum ejector to perform the purge beforehand. It is characterized in that the inside of the container 6 is evacuated.

The present invention also provides a reaction gas cylinder 1 ₁ , 1
After the switching of ₂ ..., Inert gas is fed from the pipe inert gas system 5 to the pipe and the container valve port to be pressurized and sealed, thereby performing the airtight / pressurizing clamp work.

[0011]

Since the purge system is commonly used for a plurality of reaction gas cylinders, the facility cost can be reduced, the occupied area can be reduced, and the replacement gas as the purge gas can be discarded without being used. Since it is eliminated, the use efficiency of the replacement gas is improved.

Further, since the inside of the purge container is evacuated in advance before the purge container is filled with the inert gas from the pipe inert gas system, different kinds of reaction gases in the previous purging process pass through the check valve. Even if it leaks and enters the purge container, it is possible to completely eliminate the influence of this different type of reaction gas, and at that time, since a vacuum ejector is used, it is only necessary to use a pipe inert gas system. Since a vacuum can be achieved, the system can be downsized.

After switching the reaction gas cylinder,
Since the airtight state can be inspected by using a pipe inert system, nitrogen gas having a stable pressure of about 1.2 to 1.5 times the gas pressure supplied to the reaction system can be used.
It is possible to precisely inspect the connection state and airtight state of the connection between the container valve port and the pipe without increasing the size and complexity of the system.

[0014]

EXAMPLE FIG. 2 is a conceptual configuration diagram of a residual reaction gas purging system for explaining an example of the present invention. Note that, also in FIG. 2, the two reaction gas cylinders 1 ₁ and 1
_Although only _two are shown in the figure, in reality, a large number of reaction gas cylinders are provided according to the type of reaction gas required in the semiconductor device manufacturing process.

Referring to FIG. 2, first, the first reaction gas cylinder 1₁To the first reaction system 2₁To
Piping and valves₁Second reaction gas cylinder 1 connected via
₂To the second reaction system 2₂Pipes and valves_FourConnect through
Together with the first and second reaction gas cylinders 1₁, 1₂The valve
₂,valve_FiveConnected to the common purge system 7 via
Valve the other end of the tube₃,valve₆Through the exhaust system 4 ₁, 4₂To each
Connecting.

The common purge system 7 has a purge container 6 connected to the pipe nitrogen system 5 via a valve _8, and the purge container 6 includes a valve ₉ (and valves ₂ and ₅ ) and a reverse flow. It is connected to the first reaction gas cylinder 1 ₁ and the second reaction gas cylinder 1 ₂ via the prevention valve. The valve ₁₀ is a valve connected to a pipe for connecting to another reaction gas cylinder (not shown).

On the other hand, a pipe nitrogen system 5 as a pipe inert gas system is connected to a vacuum ejector 9 via a valve ₇ and a flow meter 8, and this vacuum ejector 9 is connected to a purge container 6 via a valve _11. It is also connected to the exhaust system 4.

Here, the vacuum ejector 9 will be briefly described with reference to FIG. See FIG. 3A. The vacuum ejector 9 includes a pipe 10 connected to the pipe nitrogen system 5 via the flow meter 8, a pipe 11 connected to the exhaust system 4,
And, by being inserted into the narrowed portions of the pipes 10 and 11 and having the other end connected to the purge container 6 through the valve ₁₁ , the thin pipe 12 feeds nitrogen gas from the pipe nitrogen system 5 at high speed. The thin tube 12 is placed in a vacuum state. The purge container 6 is made of metal such as SUS304 or SUS316.

Next, a method of operating this residual reaction gas purge system will be described with reference to FIG. First, when used up a certain reaction gas cylinder, for example, the reaction gas sealed in the reaction gas cylinder 1 _1, by controlling the opening and closing of the valve by a control device not shown, the valve ₇ and the valve ₁₁ is opened,
When the valves _{8 to 10} are closed, the nitrogen gas from the piping nitrogen system 5 flows into the vacuum ejector 9 at a high speed to bring the thin tube 12 constituting the vacuum ejector 9 into a vacuum state. Therefore, the other end of the thin tube 12 is closed. Purge container 6 connected to
The gas that remains inside is discharged and a vacuum is created.

If the gas remaining in the purge container 6 is only nitrogen gas, it is not always necessary to evacuate it to a vacuum, but a small amount of reaction gas may leak and mix through the check valve. In such a case, by evacuating the purge container 6 to a vacuum prior to purging, the influence of different reaction gases such as the reaction gas in the previous purging step can be eliminated.

Then, the purge volume is adjusted with a pressure gauge (not shown).
After confirming the vacuum condition in the vessel 6, the valve ₁₁Close the valve₈To
By opening, the purge container 6 is filled with nitrogen gas.
Check the filling with a pressure gauge, and then₈To close
This completes the preparation of purging nitrogen.

[0022] Then, the valve ₉ (and the valve _2, the valve ₃₎ to open, by feeding nitrogen gas into the reaction gas cylinder 1 ₁ pipe, remaining in the container valve port inside pipes and reaction gas cylinder 1 ₁ reaction The gas is discharged together with nitrogen gas from the exhaust system 4 ₁ . If the pressure of the nitrogen gas in the purge container 6 becomes low during the process, the valve ₉ is closed, the valve ₈ is opened to newly fill the nitrogen gas, and then the same purge process is performed. repeat.

After completion of this purging step, the valve ₉ is closed, the used reaction gas cylinder ₁₁ is removed from the pipe,
By connecting a new reaction gas cylinder to the pipe,
Switch the reaction gas cylinder.

Although the switching of the reaction gas cylinder is completed for the time being, it is actually necessary to inspect / confirm the connection state of the switched new reaction gas cylinder, that is, the airtight state. FIG. 3B is a diagram showing a connection structure of a container valve opening portion of a reaction gas cylinder, and a gas leak airtightness / pressurizing clamp step which is an airtightness inspection step will be described with reference to FIG. 3B. To do.

See FIG. 3B. The container valve port 13 of the reaction gas cylinder 1 is an airtight fastening member 1.
5 is connected to one end 14 of the pipe connected to the reaction system. If the tightening is sufficient, there will be no problem, but if the tightening is insufficient, gas leakage will occur, and this gas leakage is inspected in the airtight / pressure clamping step.

Valves other than the valve connected to the purge container (valve ₁ and valve _{3 in} FIG. 2) are closed, and nitrogen gas is fed from the purge container and sealed in the pipe. In this case, the pressure of the nitrogen gas is increased to about 1.2 to 1.5 times the pressure of the reaction gas supplied to the reaction system in the semiconductor device manufacturing process.

Next, by applying soap water to the container valve port 13 of the reaction gas cylinder 1 and the one end portion 14 of the pipe, bubbles are generated when tightening is insufficient and gas leakage occurs. Check for gas leaks and confirm that there are no gas leaks before using a new reaction gas cylinder.

In the above embodiment, the reaction gas was explained as the reaction gas used in the manufacturing process of the semiconductor device, but such a residual reaction gas purge system can be used for gas switching in general chemical reaction processes. Therefore, the object of the present invention is not limited to the semiconductor device manufacturing process.

In the above embodiment, the residual reaction gas is purged in the piping system connected to the reaction gas cylinder. However, in some cases, the residual reaction gas inside the reaction system, that is, inside the reaction tube or inside the reaction chamber, may be removed. The purging may be performed by using the purging system of the present invention.

In the above embodiment, the pipe nitrogen system is used as the pipe inert gas system. However, it is not limited to the nitrogen gas, and other inert gas such as argon may be used depending on the case. It is also good.

Furthermore, in the above embodiment, the gas leak is detected using soapy water. However, when precise gas leak detection is required, the leak gas is detected using a gas detector. Is also good.

[0032]

According to the present invention, by making a purge system common to a plurality of reaction gas containers, it is possible to reduce the size and cost of the entire system and to eliminate waste associated with discarding unused purge gas. The amount used can be greatly reduced. Furthermore, since the same purge system can be used to inspect for gas leaks, the entire system can be simplified.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a principle configuration of a residual reaction gas purge system of the present invention.

FIG. 2 is a conceptual configuration diagram of a residual reaction gas purging system for explaining an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a detailed structure of a system used in an embodiment of the present invention.

FIG. 4 is a conceptual configuration diagram for explaining a conventional residual reaction gas purging system.

[Explanation of symbols]

1 Reaction gas cylinder 1 ₁ Reaction gas cylinder 1 ₂ reactive gas cylinder 2 reaction system 2 ₁ reaction 2 ₂ reaction 3-substituted gas cylinder 4 exhaust system 4 ₁ exhaust system 4 ₂ exhaust system 5 pipe inert gas system 6 purge vessel 7 purge system 8 flow Total 9 Vacuum ejector 10 Piping Piping connected to inert gas system 11 Piping connected to exhaust system 12 Capillary tube 13 Container valve opening 14 One end of piping 15 Airtight tightening member

Claims (5)

[Claims] 1. A method of purging residual reaction gas remaining inside a container valve opening of the reaction gas cylinder and a pipe connected to the reaction gas cylinder with an inert gas when switching the reaction gas cylinders, wherein each reaction system And a plurality of reaction gas cylinders connected to each exhaust system, a common purge system consisting of one purge container filled with the inert gas connected to the pipe inert gas system is used. Purging method for residual reaction gas. 2. Before the purge container is filled with the inert gas from the pipe inert gas system, the gas remaining in the purge container is exhausted to evacuate the purge container. The method for purging residual reaction gas according to claim 1. 3. The step of applying a vacuum to the inside of the purge container,
A vacuum ejector is used to perform the operation.
A method for purging residual reaction gas according to the description. 4. When a new reaction gas cylinder is attached to the pipe after completion of the residual reaction gas purging step, an inert gas is pressurized inside the container valve opening and inside the pipe by using the purge system. The method for purging residual reaction gas according to any one of claims 1 to 3, further comprising a step of filling and inspecting an airtight state. 5. The method for purging residual reaction gas according to claim 1, wherein the inert gas is nitrogen gas.