JPH04116295A - Axial flow molecular pump - Google Patents

Abstract

PURPOSE:To maintain the high-vacuum state for a long period by feeding a freezing mixture to a cooling pipe to cool stationary blades, rotating rotary blades at a high speed to discharge the gas on the intake port side to the discharge port side, and condensing and exhausting at least the liquid component contained in the gas on the stationary blades. CONSTITUTION:A cooling pipe 33 penetrates peripheral sections of stationary blades 32 supported apart from a pump case 31, and a freezing mixture such as liquid He or liquid N2 fed from a bottle 36 connected to the cooling pipe 33 is fed into the cooling pipe 33 to cool the stationary blades 32. Rotary blades 21 are rotated at a high speed in an axial flow molecular pump, the freezing mixture is fed to the cooling pipe 33 to cool the stationary blades 33 to the extremely low temperature, thus the gas in a vacuum device is discharged to an exhaust port 35 from an intake port 34, and the liquid component such as steam and oil in the gas is condensed and discharged on the stationary blades 32. The axial flow molecular pump quickly discharges the gas containing the liquid component to the outside of a vacuum device and can generate the same clean vacuum as that generated by a cryopump.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a device that creates a high vacuum in semiconductor device manufacturing equipment, etc., especially an axial flow molecular pump that can quickly discharge liquid components in gas. The aim is to provide an axial flow molecular pump that can quickly discharge the air out of the vacuum device and maintain this high vacuum state for a long period of time. It has cooling piping that penetrates the peripheral part of the
A cryogen is poured into the cooling pipe to cool the fixed blades, and the rotor blades are rotated at high speed to discharge the gas from the intake port to the exhaust port, condensing at least the liquid component contained in the gas onto the fixed blades. Configure to exhaust air.

[Industrial application field]

The present invention relates to a device for creating a high vacuum in semiconductor device manufacturing equipment, and more particularly to an axial flow molecular pump that can rapidly discharge liquid components in gas.

In the manufacture of semiconductor devices, operations such as sputtering are performed in a high vacuum, and devices that are connected to such vacuum equipment and create a high vacuum inside must quickly exhaust gases containing liquid components such as water vapor to the outside of the vacuum equipment. At the same time, it must be able to maintain this high vacuum state for a long period of time.

[Conventional technology]

FIG. 2 is a side sectional view showing a cryopump, and FIG. 3 is a side sectional view showing a conventional axial flow molecular pump.

Cryopumps shown in Figure 2 and axial flow molecular pumps shown in Figure 3 are generally used as devices for creating high vacuum inside vacuum equipment in the manufacture of semiconductor devices, etc.
As shown in FIG. 2, the cryopump includes a shield part 12 housed in a pump case 11, and a multi-stage cryopanel 13 mounted in a tower shape inside the shield part 12.
It has a baffle 14 provided to block the intake port side of the shield part 12, and a small cooler 15 and a cylinder I6.
The shield part 12, the cryopanel 13, and the baffle 14 are cooled to an extremely low temperature of 20 to 100 K by the action of a cryogen such as liquid He or liquid N2 supplied from the cooling agent.

Water vapor and gases with a higher vapor pressure are condensed and exhausted to the baffle 14 at the entrance, and nitrogen, which has a lower vapor pressure than water vapor,
Gases such as oxygen, argon, helium, and hydrogen are captured by the shield section 12 and cryopanel 13 that are cooled to an extremely low temperature. Such cryopumps can quickly discharge gases containing liquid components such as water vapor, and because they do not use oil in the pump, they provide an essentially clean vacuum, making them ideal for equipment that requires a clean vacuum. It is widely used as an exhaust pump.

Further, as shown in FIG. 3, the conventional trickle-flow molecular pump has a plurality of rotary blades 21 rotating at high speed and a plurality of fixed blades 23 fixed to a pump case 22 which are arranged alternately in the axial direction. is fixed to the motor shaft 24 of a built-in drive motor 25. When the rotary blade 21 is rotated at high speed, gas in the vacuum device (not shown) is discharged from the intake port 26 side to the exhaust port 27, and a high vacuum is created in the vacuum device.

Such axial flow molecular pumps quickly discharge gas and create a high vacuum similar to that of cryopumps, and because they can maintain this vacuum state for long periods of time, they are often used as the main exhaust pump for devices that require high vacuum. There is.

[Problem to be solved by the invention]

However, as the storage cryopump, which captures gas and creates a high vacuum, increases the operating time, its ability to capture gas decreases and the degree of vacuum decreases. Therefore, for example, it is necessary to stop operation once every 10 days for regeneration, and if you add the time required for regeneration and the time to return to a working state, it will take about 8 hours, during which time the cryopump will operate under high vacuum. The vacuum equipment that is producing it cannot be used.

In addition, conventional axial flow molecular pumps can maintain a vacuum state for long periods of time, but compared to cryopumps, the discharge rate of liquid components such as water vapor is slow, and the oil used as a lubricant for the rotating parts can adversely affect vacuum equipment. There was a problem of internal spread.

An object of the present invention is to provide an axial flow molecular pump that can quickly discharge gas containing liquid components such as water vapor out of a vacuum device and maintain this high vacuum state for a long period of time.

[Means to solve the problem]

FIG. 1 is a side sectional view showing an axial flow molecular pump according to the present invention. The same objects are represented by the same symbols throughout the figures.

The above problem involves a plurality of rotary blades 21 arranged alternately in the axial direction.
It has a fixed blade 32 and a cooling pipe 33 that penetrates the peripheral edge of the fixed blade 32, and cools the fixed blade 32 by flowing a refrigerant through the cooling pipe 33, and rotates the rotary blade 21 at high speed. The gas on the intake port 34 side is discharged to the exhaust port 35 side,
At least the liquid component contained in the gas is removed from the fixed wing 32.
This is achieved by the axial flow molecular pump of the present invention, which is configured to perform condensation and exhaust.

[Function] As shown in Fig. 1, it has a plurality of rotary blades and fixed blades arranged alternately in the axial direction, and a cooling pipe that penetrates the peripheral edge of the fixed blade. By cooling the fixed blades, rotating the rotary blades at high speed to discharge gas from the intake port side to the exhaust port side, and condensing and exhausting at least the liquid component contained in the gas to the fixed blades, It is possible to realize an axial flow molecular pump that can quickly discharge gas containing liquid components such as water vapor to the outside of the vacuum device and maintain this high vacuum state for a long time.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to FIG.

As shown in FIG. 1, the axial flow molecular pump according to the present invention has a plurality of rotary blades 21 rotating at high speed and a plurality of fixed blades 32 supported by a pump case 31, which are arranged alternately in the axial direction. The rotary blade 21 fixed to the shaft 24 is driven by a drive motor 25.

A cooling pipe 33 passes through the peripheral edge of the fixed blade 32 that is supported apart from the pump case 31.
A cryogen, such as liquid He or liquid N2, supplied from a cylinder 36 connected to the fixed blade 32 is configured to flow into the cooling pipe 33 to cool the fixed blade 32.

In such an axial flow molecular pump, the rotary blades 21 are rotated at high speed, and a refrigerant is flowed through the cooling pipe 33 to cool the fixed blades 32.
By cooling to an extremely low temperature, the gas in the vacuum device (not shown) is discharged from the intake port 34 to the exhaust port 35,
Liquid components such as water vapor and oil in the gas are condensed to the fixed blades 32 and exhausted. That is, even though it is an axial flow molecular pump, it can quickly exhaust gas containing liquid components to the outside of the vacuum device and create a clean vacuum equivalent to that of a cryopump.

Note that the ability of the axial flow molecular pump according to the present invention to condense and exhaust the liquid component decreases as the operating time increases, as in the case of cryopumps, so the ability to condense and exhaust the liquid component to the fixed blade 32 is reduced. and must be regenerated. However, this regeneration of the fixed blades 32 is easily carried out by cutting off the supply of refrigerant, and during this period it operates as a normal axial flow molecular pump, so there is no need to interrupt the processing of the vacuum device.

That is, it is possible to realize an axial flow molecular pump that can quickly discharge gas containing liquid components such as water vapor to the outside of the vacuum device and maintain this high vacuum state for a long period of time.

respectively.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an axial flow molecular pump that can quickly discharge gas containing liquid components such as water vapor and maintain this high vacuum state for a long period of time.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an axial flow molecular pump according to the present invention, FIG. 2 is a side sectional view showing a cryopump, and FIG. 3 is a side sectional view showing a conventional axial flow molecular pump. In the figure, 21 is a rotary blade, 24 is a motor shaft, 25 is a drive motor, 31 is a pump case, 32 is a fixed blade,
33 is the cooling pipe, 34 is the intake port, 35 is the exhaust port, 36 is the cylinder, 1.
Mouth fry opon 7° begging 1 look] 薯 2 fig.

Claims (1)

[Claims] A plurality of rotary blades (21) and fixed blades (32) alternately arranged in the axial direction, and a cooling pipe (33) that penetrates the peripheral edge of the fixed blades (32). the fixed blade (32) by flowing a refrigerant into the cooling pipe (33);
at the same time as rotating the rotor blade (21) at high speed to discharge gas from the intake port (34) side to the exhaust port (35) side,
An axial flow molecular pump characterized in that it is configured to condense and exhaust at least a liquid component contained in the gas to the fixed vane (32).