JPH05332253A - Vacuum generating device - Google Patents

Abstract

PURPOSE:To generate a high vacuum in a short time in a main chamber closed under the atmospheric pressure. CONSTITUTION:A plurality of auxiliary chambers 3, 4, and 5 are connected in juxtaposition on the suction side of a vacuum pump 2. The auxiliary chambers 3, 4, and 5 connected to a main chamber 1, being an object brought into a vacuum, through communicating pipes 30, 40, and 50, respectively, and on-off cocks 3a, 4a, and 5a are arranged in the middle of the communicating pipes 30, 40, and 50, respectively. The interior of each of the auxiliary chambers 3, 4, and 5 is exhausted with the aid of a vacuum pump and maintained at a constantly high vacuum. When a high vacuum is generated in the main chamber 1 closed under an atmospheric pressure, on-off cocks 3a, 4a, and 5a are released, in order, and an internal pressure in the main chamber 1 is reduced in stages through communication of it with the auxiliary chambers 3, 4, and 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for rapidly forming a high vacuum inside a main chamber which is closed under atmospheric pressure.

[0002]

2. Description of the Related Art In the manufacture of semiconductors, a wafer, which is an object to be processed, is introduced into a processing chamber, and various film forming processes are carried out while maintaining a high vacuum inside the processing chamber. In order to improve the efficiency of film processing, it is important to quickly return the inside of the processing chamber, which is exposed to the atmosphere, to a high vacuum state when carrying out and carrying in a wafer.

Therefore, conventionally, a small-volume air pressure adjusting chamber is connected to one side of the processing chamber via an openable / closable gate, and the air pressure adjusting chamber is connected to a vacuum pump together with the processing chamber.
At the time of unloading processed wafers and loading unprocessed wafers, the air pressure control chamber, which is cut off from the communication with the processing chamber by closing the gate, is opened to the atmosphere, and after unloading and loading the wafer, it is hermetically closed by a vacuum pump. There is used a semiconductor manufacturing apparatus configured to evacuate and open the gate when a predetermined degree of vacuum is reached to transfer a wafer from an atmospheric pressure adjusting chamber to a processing chamber to perform a predetermined processing. That is, according to this apparatus, since opening to the atmosphere and returning to the vacuum state are performed in the small-volume atmospheric pressure adjusting chamber, and the large-volume processing chamber is always kept in the high vacuum state, the wafer is unloaded and loaded. The time required for processing can be shortened, and highly efficient processing becomes possible.

[0004]

In the semiconductor manufacturing apparatus having the above-mentioned structure, the internal pressure of the atmospheric pressure adjusting chamber after carrying out and carrying in the wafer is set to a high vacuum state in order to further improve the processing efficiency. It is an important issue to reduce the time required for restoration. Further, not only in the manufacture of semiconductors but also in many industrial fields, similarly, there is a demand for the development of an apparatus that quickly forms a high vacuum inside a sealed chamber under atmospheric pressure.

In the conventional vacuum forming apparatus, a target main chamber is connected to the suction side of a vacuum pump, such as the pressure adjusting chamber in the semiconductor manufacturing apparatus described above, and a high vacuum is created in the main chamber by exhausting the vacuum pump. It is configured to get. FIG. 5 is a graph showing how the degree of vacuum changes with time when the main chamber closed under atmospheric pressure (1 atm) is evacuated by a vacuum pump. As is clear from this figure, in the conventional vacuum forming apparatus, the degree of vacuum sharply increases in the initial stage, but the degree of increase gradually decreases with the passage of time, and the change mode is gradually changed to the absolute vacuum indicated by the one-dot chain line in the figure. As shown in the figure, when trying to obtain a high vacuum close to an absolute vacuum like a pressure adjusting chamber in a semiconductor manufacturing apparatus, it takes a lot of time until a target high vacuum is formed inside the main chamber. is there.

The shortening of the required time can be achieved by using a vacuum pump having a sufficiently large exhaust capacity as compared with the internal volume of the main chamber. This is not a preferable method because it causes an increase in cost and operating cost.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a vacuum forming apparatus capable of forming a high vacuum in a short time inside a main chamber which is closed under atmospheric pressure. To do.

[0008]

In the vacuum forming apparatus according to the present invention, a plurality of sub-chambers are connected in parallel on the suction side of a vacuum pump, and each of these sub-chambers is connected to a main chamber via a communication pipe. An opening / closing means is provided in the middle of each communication pipe.

[0009]

In the present invention, when a plurality of sub-chambers are constantly maintained in a high vacuum state by exhausting with a vacuum pump and a vacuum is formed inside the sealed main chamber under atmospheric pressure, this main chamber is used. The chamber and the plurality of sub-chambers are sequentially connected by opening the opening / closing means in the middle of the communication pipe connecting the chambers, and a high vacuum in each sub-chamber is introduced into the main chamber. After this, the opening / closing means is closed, and the evacuation of the sub chamber is continued while being isolated from the main chamber in preparation for the next vacuum formation.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a schematic view showing an embodiment of the vacuum forming apparatus according to the present invention. In the figure, reference numeral 1 denotes a main chamber which is a target of vacuum formation, and is configured to be closed from the outside air by closing a door 10 attached to one side and open to communicate with the outside air. Further, the main chamber 1 has a vacuum pump 2 which serves as a vacuum source.
Is connected to the suction side of the exhaust pipe 20 via the exhaust pipe 20,
Is closed, and the exhaust valve 20a arranged in the middle of the exhaust pipe 20 is opened, so that the vacuum pump 2 performs exhaust.

On the suction side of the vacuum pump 2, a plurality (three in the figure) of sub-chambers 3, 4, 5 are provided for the exhaust pipes 21, respectively.
The sub-chambers 3, 4, by the vacuum pump 2 are opened by opening the exhaust valves 21a, 22a, 23a, which are connected to each other via the exhaust pipes 22, 23, and are arranged in the middle of the exhaust pipes 21, 22, 23, respectively. 5 is exhausted.

The sub-chambers 3, 4, 5 and the main chamber 1 are connected via separate communication pipes 30, 40, 50. Opening / closing cocks 3a, 4a, 5a are provided in the middle of these communication pipes 30, 40, 50, respectively, and the main chamber 1 is moved to the sub chamber 3 by the opening operation of the opening / closing cock 3a and to the opening / closing cock 4a. Sub-chamber 4 by opening operation
In addition, the sub-chambers 5 are communicated with each other by opening the opening / closing cock 5a.

In the vacuum forming apparatus constructed as described above, the exhaust valves 21a, 22 arranged in the middle of the exhaust pipes 21, 22, 23
a and 23a are always open, and the auxiliary chamber 3 by the vacuum pump 2 is
The vacuum exhaust of 4 and 5 is continuously performed, and the communication pipe
The opening / closing cocks 3a, 4a, 5a arranged in the middle of 30, 40, 50 are always closed, and the insides of the sub-chambers 3, 4, 5 are maintained at a high vacuum in a state of being cut off from the main chamber 1. ..

On the other hand, in the main chamber 1, the door 10 is opened as shown by the broken line in the figure, and after the object to be processed which requires processing under vacuum is carried into the inside, the door 10 is closed. It is sealed under atmospheric pressure and vacuum formed to obtain the high vacuum required for the process.

In forming the vacuum, first, the exhaust pipe 20
The exhaust valve 20a arranged in the middle is opened, and the vacuum pump 2 directly executes the exhaust. The evacuation ends when a relatively low predetermined vacuum level is reached, and thereafter,
The exhaust valve 20a is closed to disconnect the connection between the main chamber 1 and the vacuum pump 2, and then the opening / closing cock 3a arranged in the middle of the communication pipe 30.
Open up. Due to this opening, the main chamber 1 is communicated with the sub chamber 3 through the communication pipe 30. At this time, since the interior of the sub chamber 3 is in a high vacuum state as described above, the degree of vacuum inside the main chamber 1 is instantaneous. Will be increased.

After the internal pressure of the main chamber 1 is stabilized, the opening / closing cock 3a
To close the communication between the main chamber 1 and the sub chamber 3, and then open the opening / closing cock 4a in the middle of the communication pipe 40. Due to this opening, the main chamber 1 is communicated with the sub chamber 4 through the communication pipe 40. At this time, since the degree of vacuum inside the sub chamber 4 is higher than that inside the main chamber 1, the inside of the main chamber 1 is The degree of vacuum of will increase further with the opening.

Finally, the opening / closing cock 4a is closed to cut off the communication between the main chamber 1 and the sub chamber 4, and the opening / closing cock 5a in the middle of the communication pipe 50 is opened. Due to this opening, the main chamber 1 is communicated with the sub chamber 5 having a higher degree of vacuum via the communication pipe 50, and the degree of vacuum inside the main chamber 1 further increases with the opening.

FIG. 2 is a graph showing how the degree of vacuum inside the main chamber 1 of the vacuum forming apparatus as described above changes with time. As shown in the figure, the direct evacuation by the vacuum pump 2 in the initial stage of operation is performed only in the region where the degree of vacuum inside the main chamber 1 rapidly increases, and then the degree of vacuum inside the main chamber 1 is reduced by the opening / closing cocks 3a, 4a, 5a. Due to the communication with the sub-chambers 3, 4, and 5 due to the opening, the absolute vacuum shown by the chain line in the figure increases rapidly in stages, and the time required to reach a high vacuum state is greatly shortened. It

In the sub-chambers 3, 4, 5 after the communication, the opening / closing cocks 3a, 4a, 5a are closed to shut off the main chamber 1, and the vacuum pump 2 restarts the vacuum exhaust in this state. It As a result, the sub-chambers 3, 4, and 5 can be returned to the high vacuum state while a predetermined process is being performed on the workpiece carried into the main chamber 1, and the next vacuum formation in the main chamber 1 can be performed. At that time, a similar operation can be performed.

FIG. 3 is a schematic view showing another embodiment of the vacuum forming apparatus according to the present invention. This vacuum forming apparatus comprises a plurality (three in the figure) of sub-chambers 3, 4, 5 having an inner volume sufficiently larger than the main chamber 1 to be vacuum-formed, and the main chamber 1 is , Are connected to the auxiliary chambers 3, 4, and 5 by separate communication pipes 30, 40, and 50, and are not connected to the suction side of the vacuum pump 2.

Also in the vacuum forming apparatus as described above,
Exhaust valves 21a, 22a, 23a arranged in the middle of the exhaust pipes 21, 22, 23
Is always open, the sub-chambers 3, 4, and 5 are continuously evacuated by the vacuum pump 2, and the communication pipes 30, 40, and
The open / close cocks 3a, 4a, 5a arranged in the middle of 50 are always closed, and the interiors of the sub-chambers 3, 4, 5 are maintained in a high vacuum state while being disconnected from the main chamber 1.

When forming a vacuum in the main chamber 1, after closing the main chamber 1 under atmospheric pressure, the opening / closing cock 3a arranged in the middle of the communication pipe 30 is immediately opened. Due to this opening, the main chamber 1 is communicated with the sub chamber 3 through the communication pipe 30, the interior of the sub chamber 3 is in a high vacuum state at this time, and the internal volume of the sub chamber 3 is equal to that of the main chamber 1. Since it is sufficiently larger than that, the internal pressure of the main chamber 1 is greatly reduced from the atmospheric pressure state, and a certain degree of vacuum is instantaneously obtained.

After the internal pressure of the main chamber 1 is stabilized, the opening / closing cock 3a
To close the communication between the main chamber 1 and the sub chamber 3, and then open the opening / closing cock 4a in the middle of the communication pipe 40. Due to this opening, the main chamber 1 is communicated with the sub chamber 4 via the communication pipe 40. At this time, the degree of vacuum inside the sub chamber 4 is higher than that inside the main chamber 1, and the contents of the sub chamber 4 are higher. Since the product is sufficiently larger than that of the main chamber 1, a large pressure drop occurs inside the main chamber 1, and the degree of vacuum inside the main chamber 1 further increases with the opening.

Finally, the opening / closing cock 4a is closed to cut off the communication between the main chamber 1 and the sub chamber 4, and the opening / closing cock 5a in the middle of the communication pipe 50 is closed.
Open up. By this opening, the main chamber 1 is communicated with the sub chamber 5 having a higher degree of vacuum through the communication pipe 50, and the degree of vacuum inside the main chamber 1 further increases with the opening.

That is, in this vacuum forming apparatus, the main chamber 1 is not directly evacuated by the vacuum pump 2, and the main chamber 1 and the sub chambers 3, 4, 5 are opened by opening the opening / closing cocks 3a, 4a, 5a. Since the communication occurs immediately, the degree of vacuum inside the main chamber 1 rapidly increases stepwise with the start of the vacuum forming operation, as shown in FIG. 4, and reaches a high vacuum region close to the absolute vacuum (the one-dot chain line in the figure). The time required to get to is further shortened.

Also in this vacuum forming apparatus, the sub-chambers 3, 4 and 5 after the communication are provided with open / close cocks 3a, 4a and 5a.
The main chamber 1 is shut off by the closing of the main chamber 1 and the vacuum exhaust by the vacuum pump 2 is restarted. At this time, since the internal volumes of the sub chambers 3, 4, 5 are large, the high vacuum of each chamber 3, 4, 5 is high. There is no choice but to lengthen the time required to return to the state. That is, FIG.
The configuration shown in (1) is suitable when the processing time of the object to be processed inside the main chamber 1 is sufficiently long, and when the processing time is short, the configuration shown in FIG. 1 is preferable.

Further, in each of the above-mentioned embodiments, the three sub-chambers 3, 4, and 5 are arranged in parallel on the suction side of the vacuum pump 2. However, the number of sub-chambers is not limited to three, and two or four sub-chambers may be provided. It goes without saying that more than one sub-chamber may be provided.

[0028]

As described above in detail, in the vacuum forming apparatus according to the present invention, a plurality of sub-chambers arranged in parallel on the suction side of the vacuum pump are always maintained in a high vacuum state, and each of these sub-chambers is maintained. When a high vacuum is formed inside the main chamber that is closed under atmospheric pressure, the sub-chambers are opened sequentially by connecting the main chamber to the main chamber through a communication pipe equipped with a switching device. High vacuum is introduced into the main chamber and the degree of vacuum inside the main chamber is instantly increased, so a high vacuum can be obtained within the main chamber in a short time, and under high vacuum such as film formation processing in semiconductor manufacturing. The present invention has excellent effects such as a significant reduction in the time required for various processing steps requiring the above processing.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a vacuum forming apparatus according to the present invention.

FIG. 2 is a graph showing how the degree of vacuum obtained in the main chamber by the vacuum forming apparatus of FIG. 1 changes with time.

FIG. 3 is a schematic view showing another embodiment of the vacuum forming apparatus according to the present invention.

FIG. 4 is a graph showing how the degree of vacuum obtained in the main chamber by the vacuum forming apparatus of FIG. 3 changes with time.

FIG. 5 is a graph showing how the degree of vacuum obtained in the main chamber by a conventional vacuum forming apparatus changes with time.

[Explanation of symbols]

 1 Main chamber 2 Vacuum pump 3 Sub chamber 4 Sub chamber 5 Sub chamber 30 Communication pipe 40 Communication pipe 50 Communication pipe 3a Open / close cock 4a Open / close cock 5a Open / close cock

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[Procedure amendment]

[Submission date] November 4, 1992

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

Therefore, conventionally, a small-volume atmospheric pressure adjusting chamber is connected to one side of the processing chamber through an openable / closable gate, and the atmospheric pressure adjusting chamber is connected to a vacuum pump together with the processing chamber to process a processed wafer. At the time of unloading and loading of unprocessed wafers, the air pressure control chamber, which is cut off from the communication with the processing chamber by closing the gate, is opened to the atmosphere, and after unloading and loading of the wafer, it is sealed and evacuated by a vacuum pump There is used a semiconductor manufacturing apparatus having a structure in which the gate is opened when the vacuum degree is reached and the wafer is transferred from the atmospheric pressure adjusting chamber to the processing chamber to perform a predetermined processing. That is, according to this apparatus, since opening to the atmosphere and returning to the vacuum state are performed in the small-volume atmospheric pressure adjusting chamber, and the large-volume processing chamber is always kept in the high vacuum state, the wafer is unloaded and loaded. The time required for processing can be shortened, and highly efficient processing becomes possible.

Claims (1)

[Claims] 1. An apparatus for forming a high vacuum inside the main chamber by evacuating a main chamber closed under atmospheric pressure by a vacuum pump, wherein a plurality of vacuum pumps are connected in parallel to the suction side of the vacuum pump. A vacuum forming apparatus comprising: a sub-chamber, a separate communication pipe that communicates each of the sub-chambers with the main chamber, and an opening / closing means arranged in the middle of each communication pipe.