JPH01301961A - Exhaust pipe and vacuum unit and semiconductor manufacturing device using it - Google Patents

Abstract

PURPOSE:#?To enable slow exhaust to be achieved smoothly by detecting a pressure difference from the atmospheric pressure generated through evacuation of a pipe inside. CONSTITUTION:When, for instance, exacuation is carried out in the direction of an arrow mark, the pressure at A part is lowered due to a closed circular butterfly valve 1 and a bellows 2 shrinks by being prossed with a pressure difference from the outside atmospheric pressure. Then, the circular butterfly valve 1 opens through a link mechanism 3 connected to the bellows 2. Therefore, the pressure at A part is raised a well as B part is evacuated resulting in expan sion of the bellows to close the circular butterfly valve 1 to throttle discharge. B part is gradually evacuated by repeating the above process and the bellows 2 is perfectly shrinks with the circular butterfly valve 1 fully opened under a vacuum state allowing no pressure difference between A part and B part. Thus, slow exhaust can be achieved smoothly because dilicate alteration of conductance in response to the pressure change can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a simple slow exhaust mechanism, and particularly to a valve for vacuum piping parts suitable for vacuum equipment such as semiconductor manufacturing equipment.

[Conventional technology]

A typical conventional example is shown in FIG. 2. In this case, the semicircular butterfly 5 closes due to the flow velocity in the pipe, and the flow rate is restricted. The degree of closure at this time can be adjusted by adjusting the angle of the claw 70. The semicircular butterfly 5 is always opened by a coil spring 6, and opens and closes depending on the flow velocity. However, since it opens and closes at a certain flow velocity, no consideration was given to the small changes in j+■.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration fine variations, and it is difficult to obtain smoother changes in conductance.

An object of the present invention is to perform fine changes in conductance in response to changes in pressure and to perform smooth and slow exhaust.

[Means to solve the problem]

The above object is achieved by evacuating the inside of the tube, detecting the resulting pressure difference with atmospheric pressure, and automatically changing the conductance.

[Effect]

Referring to FIG. 1, by evacuating part A of the pipe, a pressure difference is created with the external atmospheric pressure, and the pressure fluctuations are captured by the bellows 2. As a result, bellows 2 gradually contracts,
Since the circular butterflies 1 connected by the link mechanism gradually open, slow exhaust of the part B is possible.

〔Example〕

Figure 1 shows its basic structure. slow exhaust valve 8
Mainly consists of circular butterfly 1, bellows 2, link mechanism 3,
It is composed of a coil spring 4. The operating principle is that the bellows 2 captures the pressure change caused by exhausting the air, and the link mechanism 3 moves the circular butterfly 1 to change the conductance.

The basic operating conditions for each part are that when section A of the tube is at almost atmospheric pressure, the circular butterfly 1 is closed, and conversely, when section A is at almost the ultimate vacuum, the circular butterfly 1 is fully open. Become.

The basic operation of the slow exhaust valve 8 shown in FIG. 1 will be explained. For example, when evacuation is performed from atmospheric pressure in the direction of the arrow, the circular butterfly 1 is closed, so the pressure at the part A is low, and the bellows 2 is pushed and contracted by the differential pressure with the external atmospheric pressure. Then, the circular butterfly 1 is opened by the link mechanism 3 connected to the bellows 2. Therefore, while the part B is exhausted, the pressure in the part A increases, the bellows 2 is extended, and the circular butterfly 1 is closed again to restrict the exhaust gas. By repeating this operation, part B is gradually evacuated and there is no differential pressure between parts A and B, and when a vacuum is created, the bellows 2 is completely contracted and the circular butterfly l is fully opened. The degree to which the circular butterfly 1 is fully opened and the force with which the bellows 2 expands and contracts can be adjusted by a link mechanism 3 and a coil spring 4, respectively.

Hereinafter, an application example of the present invention will be explained with reference to FIG.

FIG. 3 shows a vacuum evacuation system in a sputtering apparatus, which is one of semiconductor manufacturing equipment. The sputtering apparatus is an apparatus that introduces a process gas 15 into a sputtering chamber 13 that has been evacuated to a high vacuum state by a Talio pump 14, and forms a thin metal film on an object to be processed (for example, a semiconductor wafer) in this atmosphere. Wafers are taken in and out of the vacuum preliminary chamber 12, and switching between vacuum and atmospheric pressure is repeated each time, so a slow exhaust and slow leak mechanism is required. Furthermore, in order to prevent atmospheric residual gas from being brought into the sputtering chamber 13, the exhaust must be as close to the reach of the rotary pump 9 as possible. Therefore, as shown in this embodiment, a slow exhaust valve 8 as shown in FIG. In order to deal with this, a molecular sieve trap 11 is installed to prevent contamination of the vacuum Y-equipment chamber 12 and sputter chamber 13. In this manner, in the vacuum preparatory chamber 12, which is frequently changed between vacuum and atmosphere, by slowly evacuating the chamber at first, it is possible to prevent foreign matter from being drawn into the chamber.

Next, as another embodiment, a vacuum evacuation system in a dry etching apparatus, which is one of semiconductor manufacturing equipment, will be explained with reference to FIG. Similar to the sputtering apparatus described above, the dry etching apparatus continuously processes semiconductor wafers one by one, so it is divided into a vacuum security chamber 12 and an etching chamber 16, each equipped with a rotary pump 9 and a turbo molecular pump 1.
8 performs vacuum evacuation. After the wafer is evacuated from the vacuum preliminary chamber 12, it is transferred to the etching chamber 16, a process gas 15 for etching is introduced, and etching is performed while the pressure is kept constant by the automatic pressure control device 17. Here, the vacuum preparatory chamber 12 is equipped with a slow exhaust valve 8 in the same way as the sputtering apparatus, since the vacuum and atmospheric conditions are repeated each time a wafer is transferred. In addition, the rotary pump 9 for the etching chamber 16 also has a slow exhaust valve 8.
I installed it. Therefore, effects similar to those of a sputtering device can be obtained.

Next, as another embodiment, a vacuum evacuation system in a low-pressure CVD apparatus, which is one of semiconductor manufacturing equipment, will be explained with reference to FIG. In the low-pressure CVD apparatus, a semiconductor wafer is placed inside a process tube 2o, vacuum is evacuated using a rotary pump 9 and a mechanical booster 19, and then a process gas 15 for film formation is introduced, and the pressure is kept constant using an automatic pressure controller 17. This equipment forms a film on a wafer through a chemical reaction while maintaining the temperature. Here, when evacuating the process tube 20, a slow exhaust valve was installed because the internal volume is large and there are a large number of wafers in it, so care must be taken to prevent foreign matter from getting caught in the process tube, more so than in a sputtering device. Therefore, it was possible to prevent turbulence in the airflow at the initial stage of exhaustion.

〔Effect of the invention〕

According to the present invention, since the negative pressure generated by exhaust is used as the drive source, there is no need for an electric drive method or control, and a slow exhaust mechanism can be easily obtained, resulting in miniaturization of the exhaust system and cost reduction. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the basic structure of the present invention, FIG. 2 is a sectional view of the basic structure of the prior art, FIG. The figure is a vacuum exhaust system diagram of an etching apparatus which is an embodiment of the present invention.
The figure is an evacuation system diagram of a low-pressure CvD device that is an embodiment of the present invention. 1... circular butterfly, 2... bellows, 3...
Link mechanism, 4... Coil spring, 5... Semicircular butterfly, 6... Coil spring, 7... Claw, 8...
Slow exhaust valve, 9...Rotary pump, 10...
・Valve, 11...Molecular sieve trap, 12
... Vacuum preliminary chamber, 13 ... Sputter chamber, 14
... Cryopump, 15 ... Process gas, 16
Etching chamber, 17 Automatic pressure control device, 18 Turbo molecular pump, 19 Mechanical booster, 20 Process tube. Figure 3 1st 15...Fust area

Claims (1)

[Scope of Claims] 1. An exhaust pipe characterized by having a valve provided within the exhaust pipe, and controlling the valve according to the pressure within the exhaust pipe. 2. A semiconductor processing chamber, a pump for exhausting gas in the processing chamber, an exhaust pipe provided between the pump and the processing chamber, and a valve provided in the exhaust pipe. A semiconductor manufacturing apparatus comprising: detecting the pressure on the pump side of the exhaust pipe based on the valve, and controlling the valve according to the detected output. 3. Equipped with a vacuum processing chamber, a pump for creating a vacuum state in the processing chamber, an exhaust pipe provided between the pump and the processing chamber, and a valve provided within the exhaust pipe. A vacuum device comprising: detecting the pressure on the pump side of the exhaust pipe based on the valve, and controlling the valve according to the detected output.