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Vacuum apparatus

Vacuum apparatus description/claims

This invention relates to a vacuum apparatus and, in particular, relates to a vacuum apparatus for use in the field of manufacturing semiconductor devices, flat panel display devices, or the like.

vacuum apparatus have been used in the semiconductor manufacturing field and many other industrial fields.

The vacuum apparatus generally comprises a vacuum container and vacuum pumps for keeping the inside of the vacuum container in a vacuum or depressurized state.

The vacuum apparatus is disposed in a clean room and is configured to perform predetermined processing while introducing and exhausting a predetermined process gas into and from the vacuum container.

A vacuum apparatus of this type having vacuum pumps of a plurality of stages for use in the manufacturing field of a semiconductor device manufacturing apparatus is disclosed, for example, in Patent Document 1.

In the conventional vacuum apparatus of this type, a high vacuum pump as a first vacuum pump is connected to a reaction chamber in order to bring the inside of the reaction chamber into a depressurized or vacuum state, and a booster pump as a second vacuum pump and a back pump as a third vacuum pump are respectively arranged at a subsequent stage of the high vacuum pump.

Generally, use is made, as the high vacuum pump, of a high vacuum pump that operates in a molecular flow region of ultimate pressure (10−7 Torr or less). Specifically, a turbomolecular pump or a thread groove pump is generally used as the high vacuum pump.

The turbomolecular pump and the thread groove pump each generally have a low allowable back pressure of 1 Torr or less (specifically 0.5 Torr or less) while the pumping speed is high even with a small size. Therefore, there is/are provided, at the subsequent stage of the high vacuum pump, an intermediate/low vacuum pump or intermediate/low vacuum pumps in one or two stages which each operate at a relatively low back pressure while the ultimate pressure is relatively low.

For example, in the case where vacuum pumps are provided in two stages at the subsequent stage of the high vacuum pump, a booster pump or the like is provided subsequent to the high vacuum pump as an intermediate vacuum pump and, further, a back pump (Roots-type back pump or the like) is provided subsequent to the booster pump as a low vacuum pump that operates at a relatively low back pressure while the ultimate pressure is low.

In many cases, a gas exhausted from the reaction chamber is discarded. However, particularly when a noble gas such as krypton or xenon is used for plasma excitation, or the like, the expensive noble gas is normally recovered. In this case, the discharge side of the back pump is connected to a compressor of a recovery apparatus. The compressor of the conventional recovery apparatus merely accumulates an input gas, increases its pressure, and discharges it.

As described above, in a vacuum apparatus for use in the manufacture of a semiconductor device manufacturing apparatus, use is generally made of two or three vacuum pumps in multistages with respect to one reaction chamber (vacuum container). These vacuum pumps often have mutually different structures as described above, but are all driven by electric motors. Accordingly, in the vacuum apparatus of this type where the number of vacuum pumps used is large, the power consumption increases. Since the power consumption of the vacuum apparatus resultantly affects the manufacturing cost of the semiconductor device manufacturing apparatus, it is desired to reduce the power consumption.

Particularly, since the last-stage low vacuum pump (back pump) among the multistage vacuum pumps is required to have a large capacity, the power consumption thereof is also large. Therefore, it is effective and desirable to suppress the power consumption of the back pump for a reduction in power consumption of the entire vacuum apparatus and thus a reduction in manufacturing cost of the semiconductor device manufacturing apparatus.

Herein, the reasons of the large power consumption of the back pump are firstly that since its discharge side is the atmosphere (the atmospheric pressure is 760 Torr), the exhaust operation should always be carried out (even when the reaction chamber is not operated) in order to prevent back diffusion to the inlet side from the atmospheric side and secondly that although a depressurized gas enters from the inlet side, the gas does not go out into the atmosphere unless its pressure is increased to the atmospheric pressure or more.

Patent Document 1:

Therefore, it is an object of this invention to provide a vacuum apparatus and a vacuum pump that can suppress the power consumption.

According to this invention, there is obtained a vacuum apparatus characterized by comprising a vacuum container having a gas inlet and a gas outlet, a vacuum pump of at least one stage connected to the gas outlet of the vacuum container for depressurizing the inside of the vacuum container or maintaining the inside of the vacuum container in a depressurized state, and a compressor connected to a discharge port of the last-stage vacuum pump of the at least one-stage vacuum pump and having capability of depressurizing an input side of the compressor.

The number of vacuum pump stages is set to one stage or a plurality of stages depending on a gas amount introduced into the vacuum container or the capability of the vacuum pump.

• Provisional Patent
• Utility Patent

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