JPH081191B2 - Vacuum pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vacuum pump for connecting a reaction furnace that performs a chemical reaction such as etching of aluminum to a suction side, and particularly when used in a semiconductor manufacturing apparatus, The present invention relates to a vacuum pump suitable for preventing deposition of reaction products.

[Conventional technology]

In recent years, a vacuum atmosphere has been required in the manufacturing process of semiconductors and new materials. A vacuum pump is used to achieve this. This vacuum pump generally has a structure in which a rotor with impellers is rotated to suck gas, pressurize it by centrifugal force, and discharge it to the atmosphere side. This type of vacuum pump is described, for example, on pages 38 and 39 of Nikkei Mechanical, published on December 15, 1986.

[Problems to be Solved by the Invention] According to the above-described vacuum pump, there is a problem in that a reaction product adheres to a portion where the temperature near the exhaust port suddenly decreases and the exhaust port is blocked.

An object of the present invention is to provide a vacuum pump that can prevent reaction products from adhering to the pump.

[Means for solving the problem]

The above object is to provide a housing having an intake port and an exhaust port,
A vacuum pump, comprising a stator fixed in the housing and a rotor rotatably supported in the housing, for exhausting gas sucked from the exhaust port to an atmospheric pressure atmosphere from the exhaust port, In the final stage,
This is achieved by providing a gas supply passage communicating with the exhaust port.

[Action]

The reaction product in the reaction furnace is a gas or a liquid at a temperature of 60 to 80 ° C or higher, but becomes a solid at a temperature of about 60 ° C or lower. If the temperature near the exhaust port is low, reaction products may adhere to the vicinity of the exhaust port, and in the worst case, the piping may be completely clogged. Therefore, gas is injected from the gas supply passage of the stator section to increase the amount of compressed gas and increase the amount of heat of the exhaust gas. As a result, the amount of heat of the gas passing through the exhaust port increases, so that the temperature in the vicinity of the exhaust port rises to about 60 ° C. and the reaction product in the reaction furnace can be prevented from adhering to the exhaust port.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the vacuum pump of the present invention. In this drawing, the vacuum pump is rotated through a housing 1 having an intake port 1A and an exhaust port 1B, and a bearing 2 in the housing 1. The rotary shaft 3 is freely supported, and the centrifugal compression pump stage 4 and the circumferential flow compression pump stage 5 are sequentially arranged in the housing 1 between the intake port 1A side and the exhaust port 1B side. . Each pump stage is composed of a stator and a rotor. The rotating shaft 3 is driven by a rotor of a motor 6 attached to it. The housing 1 described above is provided with a seal fluid supply passage 7 so that the lubricating oil does not enter the exhaust port side. This seal fluid supply path 7
Is connected to a sealing fluid supply source 9 such as a cylinder by a pipe line 8. A fluid supply path 10 is provided in the last stage portion of the pump of the housing 1 described above. This fluid supply path 10 is a valve
It is connected to the conduit 8 via a conduit 12 provided with 11. The open end of the fluid supply passage 10 described above communicates with the exhaust port 1B through the space at the final stage of the pump as shown in FIGS. Nitrogen gas is used as the sealing fluid.

Next, the operation of the above-described embodiment of the vacuum pump of the present invention will be described.

The gas is compressed while being sucked in through the intake port 1A and discharged through the exhaust port 1B. On the other hand, the seal fluid from the seal fluid supply source 9 flows into the space formed by the housing 1 and the rotary shaft 3 through the pipe 8 and the seal fluid supply passage 7, and the lubricating oil to the bearing 2 is discharged to the exhaust port side. It has a sealing function to prevent intrusion. Further, a part of the sealing fluid from the sealing fluid supply source 9 flows into the final stage of the pump as purge gas through the valve 11, the pipe line 12, and the fluid supply passage 10. The purge gas that has flowed in is adiabatically compressed at the final stage of compression as shown in Figs.
Heat is taken from the stator near the inlet of 1B and the temperature rises to about 80 ° C. Normally, the number of gas flowing into the pump from the intake port 1A is as small as several hundreds atm · cc / min, so the temperature of the gas of about 80 ° C near the inlet of the exhaust port 1B is cooled while flowing through the exhaust port 1B. The temperature drops to 40 ° C. Therefore, by flowing nitrogen gas at about 10,000 atm · cc / min from the fluid supply path 10, the amount of heat of the exhaust gas increases, and it is possible to prevent a rapid temperature drop of the gas at the exhaust port 1B. As a result, it is possible to prevent the reaction product from adhering to the exhaust port 1B.

The flow rate adjusting valve 11 can be used to adjust the inflow amount of nitrogen from the bypass line so that various chemical reactions in the reactor can be handled.

Although a part of the sealing fluid is used as the gas for preventing the adhesion of the reaction product in the above-mentioned embodiment, it is possible to supply these separately.

〔The invention's effect〕

According to the present invention, since it is possible to prevent a rapid temperature drop of the gas near the exhaust port of the vacuum pump, it is possible to increase the temperature of the gas near the exhaust port as compared with the prior art without newly installing a heat source system. Since it is possible to prevent the reaction product from adhering, the cost can be reduced, the failure factors can be reduced, and the reliability can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a vacuum pump of the present invention, FIG. 2 is an enlarged vertical sectional view of an essential part of the present invention, and FIG. 3 is a sectional view taken along line III-III of FIG. Is. 1 ... Housing, 1A ... Intake port, 1B ... Exhaust port, 2 ...
... Bearing, 3 ... Rotary shaft, 4 ... Centrifugal compression pump stage, 5 ...
... Circular flow compression pump stage, 6 ... Motor, 7 ... Seal fluid supply passage, 8 ... Pipe passage, 9 ... Seal fluid supply source, 10 ...
… Fluid supply channel, 11 …… Valve, 12 …… Pipeline.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Hisashi Nishikawa 603, Jinritsu-cho, Tsuchiura-shi, Ibaraki Hitsuta Manufacturing Co., Ltd. Tsuchiura factory (56) References -67999 (JP, U)

Claims (3)

[Claims] 1. A housing having an intake port and an exhaust port, a stator fixed in the housing, and a rotor rotatably supported in the housing, wherein the gas sucked from the exhaust port is exhausted. A vacuum pump for exhausting from a port to an atmospheric pressure atmosphere, wherein a gas supply path communicating with an exhaust port is provided at the final stage of the stator. 2. The vacuum pump according to claim 1, wherein the supply side of the gas supply path communicates with a gas supply source via a valve. 3. A gas supply passage on the supply side communicates with a gas supply passage to a non-contact seal portion provided at the final stage of the rotor via a valve. The vacuum pump described.