JPH05180165A - Vacuum exhaust device for vacuum container - Google Patents

Abstract

PURPOSE:To provide a vacuum exhaust device for a vacuum container capable of improving its exhaust performance. CONSTITUTION:A vacuum exhaust device has a turbo molecular pump (main pump) 3, an oil rotating type vacuum pump (auxiliary pump) 11 and a first exhaust line 4 having a filter 7 disposed between the respective pumps to adsorb oil steam from the oil rotating type vacuum pump 11. Also, there are provided a second exhaust line 5 connected in parallel to the first exhaust line 4 and heaters 12, 13 for heating a vacuum chamber 1, the turbo molecular pump 3 and second exhaust line 5 at the temperature gradient of heating temperature rising as kept away from the oil rotating type vacuum pump 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vacuum exhaust device, and more particularly to
The present invention relates to a vacuum container vacuum exhaust device including a main pump for vacuum exhaust and an auxiliary pump for vacuum exhausting a vacuum container using oil.

[0002]

2. Description of the Related Art For example, in a thin film forming apparatus, an analyzing apparatus, etc., an evacuation apparatus is used as an apparatus for evacuating a vacuum chamber. As shown in FIG. 2, this vacuum pumping apparatus includes a main pump such as a turbo molecular pump (TMP) 22 connected to a vacuum chamber (CH) 20 through a shutoff valve 21, and an oil pump connected to the main pump. And a rotary vacuum pump (RP) 23.

When evacuating, the shutoff valve 21 is opened,
The inside of the vacuum chamber 20 is evacuated by driving the turbo molecular pump 22 and the oil rotary vacuum pump 23. However, in such a vacuum exhaust device, since the oil rotary vacuum pump 23 becomes high temperature during vacuum exhaust, the oil vapor from the oil rotary vacuum pump 23 flows back to the turbo molecular pump 22 side through the exhaust line. The problem arises.
As a result, the exhaust performance of the vacuum exhaust device deteriorates.

Therefore, in order to prevent the backflow of oil vapor from the oil rotary vacuum pump to the turbo molecular pump side, a vacuum exhaust device as shown in FIG. 3 has already been put into practical use. In the vacuum exhaust device shown in FIG. 3, the turbo molecular pump 22 is used.
2 is different from the vacuum exhaust device of FIG. 2 in that a shutoff valve 24 and a filter (FLT) 25 are connected between the oil rotary vacuum pump 23 and the oil rotary vacuum pump 23. The filter 25 is composed of a suction trap.

When performing vacuum exhaust using this exhaust device, the shut-off valves 21 and 24 are opened and the turbo molecular pump 22 and the oil rotary vacuum pump 23 are driven. When the oil rotary vacuum pump 23 is driven, the oil rotary vacuum pump 23
The oil vapor from the turbine tries to flow back to the upstream side of the exhaust line, but this oil vapor is adsorbed by the adsorption trap in the filter 25. As a result, the oil vapor from the oil rotary vacuum pump 23 passes through the shutoff valve 24 and the turbo molecular pump 2
2 is prevented.

However, in such a vacuum exhaust device,
During baking, which is generally performed prior to the above-described vacuum evacuation process, to evacuate the vacuum chamber 20 while heating it, the released gas containing water vapor from the vacuum chamber 20 passes through the exhaust line to the adsorption trap in the filter 25. Adsorbed. As a result, the adsorption trap is clogged, and the back pressure of the turbo molecular pump 22 increases. As a result, there arises a problem that exhaust performance is deteriorated.

An object of the present invention is to provide a vacuum evacuation device for a vacuum container which can improve the evacuation performance.

[0008]

A vacuum evacuation device for a vacuum container according to the present invention comprises a main pump, an auxiliary pump, first and second evacuation lines, and heating means. The main pump is connected to a vacuum container and is used to evacuate the vacuum container. The auxiliary pump is connected to the main pump and is used to evacuate the vacuum container using oil. The first exhaust line is provided between the pumps and has an adsorption trap for adsorbing the oil vapor from the auxiliary pump. The second exhaust line is connected in parallel to the first exhaust line between the pumps. The heating means is arranged around the vacuum container, the main pump, and the second exhaust line, and heats the vacuum container, the main pump, and the second exhaust line with a temperature gradient such that the heating temperature increases as the distance from the auxiliary pump increases. It is a thing.

[0009]

In the present invention, the heating means heats the vacuum container, the main pump, and the second exhaust line during baking for drawing a vacuum while heating the vacuum container. Then, the main pump and the auxiliary pump are driven to evacuate the vacuum container through the second exhaust line. In this case, there is a temperature gradient such that the setting of the heating temperature by the heating means increases as the distance from the auxiliary pump increases. Therefore, the saturated vapor pressure in the second exhaust line increases as it approaches the main pump side in the second exhaust line. As a result, it is possible to prevent the oil vapor from the auxiliary pump from flowing back to the main pump side through the second exhaust line.

Also, during high vacuum exhaust after baking,
The main pump and the auxiliary pump are driven to perform vacuuming through the first exhaust line. At this time, the oil vapor from the auxiliary pump is adsorbed by the adsorption trap of the first exhaust line. In this case, since the first and second exhaust lines are connected in parallel, the second exhaust line is used under heating by the heating means at the time of baking, and the first exhaust line is used at the time of high-vacuum exhaust. The backflow of oil vapor from the pump can be prevented, and the adhesion of water vapor to the adsorption trap can be prevented to prevent the performance of the adsorption trap from deteriorating. In this way, the exhaust performance can be improved.

[0011]

1 shows an embodiment of the present invention. In FIG. 1, a vacuum chamber (CH) 1 is a chamber for performing a film forming process on a substrate (not shown). A turbo molecular pump (TMP) 3 as a main pump is connected to the vacuum chamber 1 via a shutoff valve 2. A first exhaust line 4 and a second exhaust line 5 are connected in parallel to the turbo molecular pump 3.

A cutoff valve 6, a filter (FLT) 7 and a cutoff valve 8 are connected in series to the first exhaust line 4. The filter 7 is composed of an adsorption trap. The second exhaust line 5 is provided with shutoff valves 9 and 10 at both ends thereof. An oil rotary vacuum pump (RP) 11 as an auxiliary pump is connected to the first and second exhaust lines 4 and 5.

A heater 12 for baking is arranged around the vacuum chamber 1, the shutoff valve 2 and the turbo molecular pump 3. In addition, around the second exhaust line 5,
A heater 13 is provided to prevent backflow of oil vapor from the oil rotary vacuum pump 11. Each heater 12, 1
The heating temperature of No. 3 is set to a temperature gradient such that the heating temperature rises toward the upstream side (upper side of FIG. 1).

Next, the operation of the above embodiment will be described. At the time of baking, the heater 12 heats the vacuum chamber 1, the shutoff valve 2, and the turbo molecular pump 3, and the heater 13 heats the second exhaust line 5. Then, the shutoff valves 2, 9 and 10 are opened and the shutoff valves 6 and 8 are closed. From this state, the turbo molecular pump 3 and the oil rotary vacuum pump 11 are driven. Then, the release gas containing water vapor in the vacuum chamber 1 is discharged to the outside of the apparatus by the turbo molecular pump 3, the second exhaust line 5, and the oil rotary vacuum pump 11.

During the baking, the oil rotary vacuum pump 11 becomes hot and oil vapor is generated. on the other hand,
The setting of the heating temperature of the heater 13 in the second exhaust line 5 has a temperature gradient that increases as it goes to the upstream side (the turbo molecular pump 3 side) of the second exhaust line 5, as described above. As a result, the saturated vapor pressure increases as it goes upstream in the second exhaust line 5. As a result, the oil vapor from the oil rotary vacuum pump 11 is prevented from flowing back to the turbo molecular pump 3 side through the second exhaust line 5.

Next, during high vacuum evacuation, the heaters 12 and 13 are stopped, the shutoff valves 9 and 10 are closed, and the shutoff valves 6 and 8 are opened. From this state, the chamber 1 is evacuated by driving the turbo molecular pump 3 and the oil rotary vacuum pump 11. At this time, the oil rotary vacuum pump 1
The oil vapor from 1 is adsorbed by the adsorption trap in the filter 7. As a result, the oil vapor from the oil rotary vacuum pump 11 passes through the first exhaust line 4 and the turbo molecular pump 3
It prevents backflow to the side. Further, in this case, since the released gas containing water vapor in the vacuum chamber 1 is removed by the above-described baking, the water vapor from the chamber 1 is not adsorbed by the adsorption trap in the filter 7 and the clogging thereof is prevented. Is prevented. This can prevent the performance of the adsorption trap from deteriorating.

As described above, during baking, the second exhaust line 5 is used to discharge the discharge gas containing water vapor in the chamber 1, and the heater 13 prevents the reverse flow of the oil vapor from the oil rotary vacuum pump 11. Further, during high vacuum evacuation, the first evacuation line 4 is used for vacuum evacuation, and the filter 7 prevents reverse flow of oil vapor from the oil rotary vacuum pump 11 to the turbo molecular pump 3. This improves the exhaust performance.

[0018]

In the vacuum evacuation device for a vacuum container according to the present invention, since the first and second evacuation lines and the heating means as described above are provided, the evacuation performance can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is a diagram corresponding to FIG. 1 of a conventional device.

FIG. 3 is a diagram corresponding to FIG. 1 of a conventional device.

[Explanation of symbols]

 1 Vacuum Chamber 3 Turbo Molecular Pump 4 First Exhaust Line 5 Second Exhaust Line 11 Oil Rotary Vacuum Pump 12, 13 Heater

Claims (1)

[Claims] 1. A main pump connected to a vacuum container for evacuating the vacuum container; an auxiliary pump connected to the main pump for evacuating the vacuum container using oil; A first exhaust line disposed between the pumps and having an adsorption trap for adsorbing oil vapor from the auxiliary pump; a second exhaust line connected in parallel to the first exhaust line between the pumps; A heating means that is arranged around the vacuum container, the main pump and the second exhaust line, and that heats the vacuum container, the main pump and the second exhaust line with a temperature gradient such that the heating temperature increases as the distance from the auxiliary pump increases. And a vacuum evacuation device for a vacuum container.