JP4027564B2 - Vacuum exhaust system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an evacuation system suitable for an application of evacuating a gas having a relatively large flow rate, such as an evacuation system of a vacuum chamber for introducing a process gas used in a semiconductor manufacturing process or the like.
[0002]
[Prior art]
FIG. 1 is a diagram showing the configuration of a conventional evacuation system of this type. The exhaust line includes a main exhaust line L1 that exhausts gas in the vacuum chamber 1 during a normal process, and a roughing line L2 that is used when the vacuum chamber 1 is roughed or when the vacuum chamber 1 is dry cleaned. Yes.
[0003]
An adaptive pressure control valve (hereinafter referred to as “APC valve”) 2, a gate valve 3, a turbo molecular pump as a main vacuum pump 4, and a gate valve 5 are inserted and connected to the main exhaust line L 1, and an APC is connected to the roughing line L 2. A valve 6 and a gate valve 7 are inserted and connected. Further, a dry vacuum pump 8 is connected as an auxiliary pump on the downstream side from the junction 10 of the main exhaust line L1 and the roughing line L2. Further, 9 is a controller of the main vacuum pump 4 and 11 is a vacuum gauge for measuring the pressure in the vacuum chamber. The downstream side of the main vacuum pump 4 does not need to be regulated in particular, and no APC valve is arranged.
[0004]
In the vacuum evacuation system having the above-described configuration, for example, when dry cleaning using NF ₃ gas is performed in order to remove a product adhered in the vacuum chamber 1, the main evacuation to which the main vacuum pump 4 is connected is performed. The line L1 is closed and the roughing line L2 is used. Recently, dry cleaning of the APC valve 2, the gate valve 3, and the main vacuum pump 4 disposed on the intake side of the main vacuum pump 4 in the main exhaust line L <b> 1 has also been performed. In this method, the main vacuum pump 4 is stopped and the APC valve 2 and the gate valve 3 are fully opened.
[0005]
The main vacuum pump 4 is stopped, the APC valve 2 and the gate valve 3 are fully opened, and the APC valve 2, the gate valve 3 and the main vacuum pump 4 are dry-cleaned. The main vacuum pump 4 is stopped and restarted. There was a problem that it took time and could not be carried out frequently. Further, if it is frequently performed, there is a problem that the time for performing the original process is reduced, and as a result, the throughput is reduced.
[0006]
Further, as a method of simultaneously performing the cleaning in the vacuum chamber 1 and the dry cleaning of the APC valve 2, the gate valve 3 and the main vacuum pump 4 on the intake side of the main vacuum pump 4 while the main vacuum pump 4 is kept rotating. There is also a method of adjusting the pressure in the vacuum chamber 1 with the APC valve 2 on the intake side of the vacuum pump 4 and exhausting with the main vacuum pump 4. However, in this method, the upstream side of the APC valve 2 has a high pressure and a sufficient cleaning effect can be obtained, but the downstream side of the APC valve 2 has a low pressure and a sufficient cleaning effect cannot be obtained. There's a problem.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and is a vacuum exhaust capable of exhibiting a sufficient cleaning effect by simultaneously performing dry cleaning of the vacuum chamber, the main vacuum pump, the APC valve on the intake side of the main vacuum pump, and the gate valve. The purpose is to provide a system.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention described in claim 1 is a vacuum chamber for introducing a gas and an exhaust system for exhausting the gas introduced into the vacuum chamber, wherein the gas introduced into the vacuum chamber is exhausted. A main exhaust line is provided, a main vacuum pump for exhausting the gas introduced into the vacuum chamber to the main exhaust line and reducing the pressure to a desired pressure is inserted and connected, and a gate valve is provided on the intake side of the main vacuum pump of the main exhaust line. a first adaptive pressure control valve, while the main exhaust side of the vacuum pump a second adaptive pressure control valves are sequentially inserted and connected is provided to rotate the main vacuum pump in any rotation speed, the second adaptive The pressure in the vacuum chamber is adjusted to a desired pressure with a pressure control valve.
[0010]
The invention described in claim 2 is a vacuum chamber for introducing a gas and an exhaust system for exhausting the gas introduced into the vacuum chamber, wherein a main exhaust line for exhausting the gas introduced into the vacuum chamber is provided. A main vacuum pump for exhausting the gas introduced into the vacuum chamber to the main exhaust line and reducing the pressure to a desired pressure is inserted and connected, and a gate valve and a first adaptive on the intake side of the main vacuum pump of the main exhaust line the pressure control valve is provided with a second adaptive pressure control valves are sequentially inserted into and connected to an exhaust side of the main vacuum pump, provided the rotational speed control means for controlling the rotational speed of the main vacuum pump, the second adaptive pressure control Inside the vacuum chamber by controlling the number of rotations of the main vacuum pump by means of valve operation and number of rotations control means The wherein the pressure regulated to a desired pressure.
[0011]
The invention described in claim 3 is characterized in that, in the vacuum exhaust system according to claim 1 or 2, an auxiliary pump is provided on the downstream side of the second adaptive pressure control valve of the main exhaust line . .
[0013]
While the main vacuum pump is rotated at an arbitrary rotation number as described above, the internal pressure of the vacuum chamber is adjusted to a desired pressure by the operation of the APC valve provided on the downstream side of the main vacuum pump in the main exhaust line , or while since pressure regulating the vacuum pressure in the chamber to a desired pressure by the rotation speed control of the operation and the main vacuum pump of the APC valve, for example in the case of the vacuum chamber dry cleaning rotates the main vacuum pump in any rotation speed Further, it is possible to carry out dry cleaning having a sufficient cleaning effect by keeping the pressure of the vacuum chamber and the main vacuum pump high.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing the configuration of the vacuum exhaust system according to the present invention. 2, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. The exhaust line includes a main exhaust line L1 that exhausts gas in the vacuum chamber 1 during a normal process, and a roughing line L2 that is used when the vacuum chamber 1 is roughed or when the vacuum chamber 1 is dry cleaned. This is the same as the vacuum exhaust system in FIG.
[0015]
A turbo molecular pump as an APC valve 2, a gate valve 3, and a main vacuum pump 4 is inserted and connected to the main exhaust line L1, and an APC valve 12 and a gate valve 5 are inserted and connected to the downstream side of the main vacuum pump 4. Yes. Further, only the gate valve 7 is inserted and connected to the roughing line L2. A dry vacuum pump 8 is connected as an auxiliary pump downstream from the junction 10 of the main exhaust line L1 and the roughing line L2.
[0016]
The pressure in the main vacuum pump 4 is measured by the vacuum gauge 11, the pressure in the main exhaust line L1 is measured by the vacuum gauge 13, and the APC valve 2 on the intake side of the main vacuum pump 4 and the downstream side of the main vacuum pump are measured. This is used to control the APC valve 12. The rotation speed of the main vacuum pump 4 is controlled by the controller 9.
[0017]
In the vacuum exhaust system having the above configuration, when the vacuum chamber 1 is roughed, the gate valves 3 and 5 of the main exhaust line L1 are closed, the gate valve 7 of the roughing line L2 is opened, and the dry vacuum pump 8 is used. The inside of the vacuum chamber 1 is roughed (at this time, the turbo molecular pump as the main vacuum pump 4 is in an operating state or a stopped state). When the inside of the vacuum chamber 1 is depressurized and depressurized to a predetermined pressure, the gate valve 7 is closed, the gate valves 3 and 5 are opened, and a normal process operation is started (at this time, the turbo molecular pump as the main vacuum pump 4 is If it is stopped, operate the turbo molecular pump).
[0018]
When the pressure on the upstream side is increased by the APC valve 12 on the downstream side of the main vacuum pump 4, the main vacuum pump 4 is overloaded, and depending on the conditions, the operating range of the main vacuum pump 4 may be exceeded. unknown. At this time, if the rotation speed of the main vacuum pump 4 is decreased by the controller 9, an increase in the rotor temperature or motor temperature of the main vacuum pump 4 during overload operation can be suppressed.
[0019]
Further, the rotational speed change (reduction in rotational speed) during overload operation is significantly shorter than the change time during no-load operation, and the rotational speed change (reduction in rotational speed) can be obtained in a short time. . Further, if the rotation speed of the main vacuum pump 4 is decreased by changing the rotation speed of the vacuum chamber 1 with only the APC valve 12 on the downstream side of the main vacuum pump 4, even higher pressure can be regulated. The upstream pressure of the APC valve 2 on the intake side of the main vacuum pump 4 is high and a sufficient cleaning effect can be obtained, but the pressure on the downstream side of the APC valve 2 is low and a sufficient cleaning effect is obtained. Can solve the problem of not being able to.
[0020]
The APC valve 12 on the downstream side of the main vacuum pump 4 may directly adjust the pressure in the vacuum chamber 1, and the relationship between the pressure in the vacuum chamber 1 and the back pressure with respect to the rotation speed of the main vacuum pump 4 can be obtained in advance. For example, the pressure in the vacuum chamber 1 can be adjusted by adjusting the back pressure of the main vacuum pump 4.
[0021]
In addition, although the example which uses a turbo-molecular pump for the main vacuum pump 4 was shown in the said example, the main vacuum pump 4 is not limited to a turbo-molecular pump.
[0022]
The main points of the present invention are the number of rotations of the main vacuum pump 4 and the pressure control of the vacuum chamber 1 by the APC valve 12 provided on the downstream side of the main vacuum pump 4. Therefore, the presence / absence of the roughing line L2 or the presence / absence of the APC valve 6 installed in the roughing line L2 does not matter. Further, the positions of the APC valve 2 and the gate valve 3 on the intake side of the main vacuum pump 4 may be arranged opposite to those in FIG. Also, the positions of the APC valve 12 and the gate valve 5 on the downstream side of the main vacuum pump 4 may be arranged opposite to those in FIG.
[0023]
【The invention's effect】
As described above, according to the invention described in each claim, the following excellent effects can be expected.
[0024]
While the main vacuum pump is rotated at an arbitrary rotational speed, or adjusting the vacuum pressure in the chamber to a desired pressure by the operation of the APC valve provided on the downstream side of the main vacuum pump in the main exhaust line, or the A PC valve since pressure operation and adjusting the vacuum pressure in the chamber to a desired pressure by the rotation speed control of the main vacuum pump, for example, while in the case of the vacuum chamber dry cleaning has a main vacuum pump is rotated at an arbitrary rotational speed, a vacuum chamber, Dry cleaning having a sufficient cleaning effect can be carried out while keeping the pressure of the main vacuum pump high.
[0025]
According to the third aspect of the present invention, dry cleaning of the main vacuum pump, the APC valve on the intake side of the main vacuum pump, and the gate valve can be simultaneously performed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a conventional vacuum exhaust system.
FIG. 2 is a diagram showing a configuration of an evacuation system according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 APC valve 3 Gate valve 4 Main vacuum pump 5 Gate valve 6 APC valve 7 Gate valve 8 Dry vacuum pump 9 Controller 10 Junction point 11 Vacuum gauge 12 APC valve 13 Vacuum gauge

Claims (3)

A vacuum chamber for introducing gas, and an exhaust system for exhausting the gas introduced into the vacuum chamber,
A main exhaust line for exhausting the gas introduced into the vacuum chamber is provided,
Is inserted the main vacuum pump for depressurizing connected to the evacuated and desired pressure gas introduced into the vacuum chamber to the main exhaust line, a gate valve and the first to the intake side of the main vacuum pump of the main exhaust line adaptive a pressure control valve, provided the second adaptive pressure control valves are sequentially inserted into and connected to an exhaust side of the main vacuum pump,
An evacuation system characterized in that the internal pressure of the vacuum chamber is adjusted to a desired pressure by the second adaptive pressure control valve while the main vacuum pump is rotated at an arbitrary rotational speed. A vacuum chamber for introducing gas, and an exhaust system for exhausting the gas introduced into the vacuum chamber,
A main exhaust line for exhausting the gas introduced into the vacuum chamber is provided,
Is inserted the main vacuum pump for depressurizing connected to the evacuated and desired pressure gas introduced into the vacuum chamber to the main exhaust line, a gate valve and the first to the intake side of the main vacuum pump of the main exhaust line adaptive a pressure control valve, provided the second adaptive pressure control valves are sequentially inserted into and connected to an exhaust side of the main vacuum pump,
A rotation speed control means for controlling the rotation speed of the main vacuum pump is provided;
An evacuation system characterized in that the internal pressure of the vacuum chamber is regulated to a desired pressure by the operation of the second adaptive pressure control valve and the rotational speed control of the main vacuum pump by the rotational speed control means. The evacuation system according to claim 1 or 2,
An evacuation system according to claim 1 , wherein an auxiliary pump is provided on the downstream side of the second adaptive pressure control valve in the main exhaust line.

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