JPH11182425A - Trap device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a trap device which is capable of increasing an extent of trap efficiency as satisfying the allowable conductance of a vacuum chamber in a coating process or the like, and besides, there is a reduction in equipment and running cost. SOLUTION: In this trap device to be set up in an exhaust piping being evacuated from an air tight chamber by a vacuum pump, it is equipped with an airtight vessel 22 constituting a part of this exhaust piping and a trap part being set up in this vessel and eliminating by sticking a produced matter in the exhaust respectively, and a flow control gas port 49, letting flow control gas run out so as to promote a flow of exhaust gas go toward the trap part is installed in the vessel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trap device used in a vacuum exhaust system used to evacuate a vacuum chamber of a semiconductor manufacturing apparatus, for example.

[0002]

2. Description of the Related Art A conventional vacuum pumping system will be described with reference to FIG. Here, the vacuum chamber 10 is a process chamber used for a semiconductor manufacturing process such as an etching apparatus or a chemical vapor deposition apparatus (CVD).
2 are connected. The vacuum pump 12 is for raising the pressure of the process exhaust gas from the vacuum chamber 10 to the atmospheric pressure. Conventionally, an oil rotary pump is used, and at present, a dry pump is mainly used. When the degree of vacuum required by the vacuum chamber 10 is higher than the ultimate degree of vacuum of the dry pump 12, an ultra-high vacuum pump such as a turbo molecule may be further arranged upstream of the dry pump.

[0003] Since the exhaust gas of a process is toxic or explosive depending on the type of the process, it cannot be directly discharged to the atmosphere. Therefore, an exhaust processing device 20 is disposed downstream of the vacuum pump 12. Of the exhaust gas from the process whose pressure has been raised to the atmospheric pressure, those which cannot be released to the atmosphere as described above are subjected to treatments such as adsorption, decomposition and absorption, and only harmless gases are released to the atmosphere. The pipe 14 is provided with a valve at an appropriate position as needed.

In the above-described conventional evacuation system, when a substance having a high sublimation temperature is present in a reaction by-product, the gas is exhausted by a vacuum pump. There is a disadvantage that it precipitates in the pump and causes a failure of the vacuum pump.

For example, when BCl ₃ or Cl ₂ which is a typical process gas is used for etching aluminum, a reaction between the remaining gas of the process gas of BCl ₃ and Cl ₂ and AlCl ₃ is performed from the process chamber. By-products are evacuated by a vacuum pump. This AlCl ₃ does not precipitate on the suction side of the vacuum pump because the partial pressure is low. However, the partial pressure rises during pressurization and exhaust, and precipitates and solidifies in the vacuum pump, and adheres to the inner wall of the pump to cause vacuum pumping. Cause failure. The same applies to the case of a reaction by-product such as (NH ₄ ) ₂ SiF ₆ or NH ₄ Cl generated from a CVD apparatus for forming a SiN film.

Conventionally, measures against this problem have been taken such as heating the entire vacuum pump to prevent solid substances from depositing inside the vacuum pump and passing the gas through the vacuum pump in a gaseous state. However, this measure is effective for precipitation in the vacuum pump, but as a result, solidified substances precipitate in the exhaust treatment device located downstream of the vacuum pump, causing clogging of the packed bed. There was a problem.

[0007] Therefore, it is conceivable to attach a trap device upstream or downstream of the pump to attach the product, remove components that generate solidified material first, and protect various devices provided in the exhaust pipe. . As such a trap device 100, as shown in FIG. 5 or FIG. 6, an airtight container 102 forming a part thereof is disposed in an exhaust pipe,
A configuration in which, for example, a plate-shaped baffle 104 (trap portion) is provided therein is conceivable. When a certain amount of deposits adhere to the baffle 104, the exhaust path is switched to perform cleaning or replacement of the trap, and the processing is continued.

[0008]

However, in the conventional trap device, the trap efficiency is low, and about 60% of the components in the exhaust gas flow directly without adhering to the trap portion and adhere to downstream pipes and various devices. I was this is,
Since the configuration of the baffle 104 is a parallel plate, the exhaust and the trap portion are not sufficiently contacted with each other, and the exhaust is exhausted to a portion where the trap efficiency is low in the airtight container such as a gap between the wall of the container 102 and the baffle. Is considered to flow and pass through without being processed.

Although the gap between the vessel wall and the baffle can be reduced, too small a gap causes a partial decrease in conductance, which causes clogging by solid matter trapped therein and causes an unstable flow of exhaust gas. In addition, problems such as the inability to smoothly replace or switch the trap portion occur.

[0010] The present invention has been made in view of the above-described circumstances, and can improve trap efficiency while satisfying the conductance allowed by a vacuum chamber in a film forming process or the like, without affecting the performance of a vacuum pump. Another object of the present invention is to provide a trap device capable of improving the reliability of operation by extending the life of a vacuum pump and protecting an abatement apparatus, and further reducing equipment and operation costs.

[0011]

According to a first aspect of the present invention, there is provided a trap device disposed in an exhaust pipe for exhausting air from a hermetic chamber by a vacuum pump, wherein the airtight container forming a part of the exhaust pipe is provided. A trap portion disposed in the container for adhering and removing products in the exhaust gas, and flowing a flow control gas through the container so as to promote the flow of the exhaust gas toward the trap portion. A trap device provided with a flow control gas port.

Thus, the trap efficiency can be improved while securing a certain amount of space inside the trap container and ensuring stable operation without excessively lowering the conductance. The flow control gas preferably has a component and a temperature that do not affect the trapping operation of the trap section and the post-treatment process of the exhaust, and an inert gas such as a nitrogen gas is used.

According to a second aspect of the present invention, the flow control gas port is provided to flow the flow control gas along an inner wall surface of the container. It is a trap device.
The space along the inner wall surface of the container is a portion deviated from the center of the trap flow path, and the inner wall surface of the container itself often has low trapping efficiency or is not a trapping surface, so that exhaust does not flow through this portion. By doing so, the trap efficiency is improved. Further, since the processing gas does not easily leak to the outside, the sealing property is also improved.

The invention according to claim 3 is the trap device according to claim 1, wherein the trap portion has a baffle having a curved trap surface. As a result, a bent trap flow path is formed, and the probability that gas molecules collide with the trap surface increases, and the trap efficiency increases.

According to a fourth aspect of the present invention, there is provided the trap device according to the third aspect, wherein the trapping surface is formed in a shape of a circular arc whose axis intersects the exhaust passage. Thus, a baffle having a curved trap surface can be realized with a relatively simple configuration.

The invention according to claim 5 is the trap device according to claim 1, wherein the trap portion is provided so as to be able to be taken in and out of the container.
This makes it easy to replace or regenerate traps. It is preferable to provide a sealing mechanism and a driving mechanism for the mechanism for taking in and out.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a first embodiment of a trap device according to the present invention, which is provided on the left and right sides of an exhaust pipe 14 for exhausting an airtight chamber 10 shown in FIG. A regeneration pipe 16 is disposed adjacent to the exhaust pipe 14 and the regeneration pipe 1.
6 is a switchable trap device provided with two trap portions 18 which are linearly moved in a direction intersecting the direction 6 (hereinafter referred to as an intersecting direction) and are switchably disposed.

This switching type trap device has an exhaust pipe 14
And a cylindrical container 22 disposed over the regeneration pipe 16
And a shaft 24 that penetrates the container 22 in the cross direction, and an air cylinder 26 that is a driving unit that reciprocates the shaft 24 in the axial direction. The container 22 includes a partition 27 having an opening at the center and a partition plate 28 attached to the shaft 24.
The chamber is partitioned into a trap chamber 30 and a regeneration chamber 32 by the exhaust pipe 14 or the regeneration pipe 16 respectively.
Is connected.

A bellows 34 is provided between the air cylinder 26 and the container 22 to maintain airtightness therebetween. Further, an O-ring 35 is disposed at a position where the partition 27 and the partition plate 28 are in contact with each other to maintain the airtightness between the trap chamber 30 and the regeneration chamber 32. The partition plate 28 is formed of a material having a high heat insulating property so as to prevent heat transfer between the trap chamber 30 and the regeneration chamber 32.

The trap portion 18 includes a pair of end plates 36 attached to the shaft body 24 in the axial direction, and baffle plates 38a, 38b, 38 provided between these end plates.
c. Baffle plates 38a, 38b,
38c are arranged symmetrically (six in the illustrated example), and trap flow paths 40a, 40b, 40c, and 40d are formed between them and between the shaft body 24 and the container wall. In this example, the baffle plates 38 a, 38 b, and 38 c are formed by the arcuate surface portion 42 and the flat portion 4 forming the upper and lower communication portions.
4 as needed. Baffle plates 38a, 38
b, 38c and the end plate 36 are each formed of a material having good heat conductivity, and are provided with baffle plates 38a, 38b, 38.
c is cooled by heat conduction between the shaft 24 and the end plate 36.

The shaft body 24 is formed of a material having good heat conductivity such as a metal, and has a heat medium passage 46 for cooling formed therein. A cooling medium such as a liquid such as liquid nitrogen or cooled air or water is supplied to the heating medium channel 46.

In the vicinity of the inlet of the exhaust passage 14 of the trap chamber 30, there is provided a flow control gas port 48 which opens on the left and right walls of the container 22 and supplies a flow control gas in a direction orthogonal to the exhaust flow. ing. The flow control gas port 48 is connected to a flow control gas source that supplies an inert gas such as nitrogen at a predetermined pressure and flow rate. The pressure or flow rate of the flow control gas supplied from the flow control gas port 48 is set so that the flow control gas flows only through the outermost trap flow path 40d.

The operation of the trap device configured as described above will be described. By the operation of the vacuum pump 12, the gas discharged from the chamber 10 is introduced into the trap container 22 through the exhaust pipe 14. At the inlet of the trap container 22, a flow control gas of a predetermined pressure and flow rate flows from the left and right flow control gas ports 48, and therefore, the exhaust gas is discharged to the trap flow paths 40a, 40 on the center side.
b, 40c, and hardly flows into the outermost trap channel 40d. Further, the flow control gas flows through the outermost trap flow path 40d and does not flow through the inner trap flow paths 40a, 40b, and 40c.

The exhaust gas is supplied to the baffle plates 38a, 38b, 38
c, curved trap channels 40a, 40b, 40c
, And is cooled by hitting the baffle plates 38a, 38b, 38c. The easily condensed components in the cooled exhaust gas precipitate there, and the deposited solid adheres to the inner and outer surfaces of these baffle plates.

Thus, the outermost trap flow path 40 between the wall of the container 22 having almost no trapping action.
Since almost no exhaust gas flows through d, the trap efficiency is prevented from lowering. According to an experimental example by the inventor, the trap efficiency was 60% when the width t of the outermost flow path 40d was 19 mm and the flow control gas was not blown, whereas the flow control gas was 10 SCCM. When blown, it improved to 85%.

In this embodiment, the trap flow path 40
Since a, 40b, 40c, and 40d are formed in a curved shape, the probability that gas molecules in the exhaust will hit the trap surface increases, and the efficiency of cooling and trapping is improved. This is the same not only for the trap by cooling but also for the trap for adsorbing particles on the trap surface. The trap portion 18 to which a predetermined amount of solid matter adheres is
The operation is switched to the reproduction room 32 by the operation of 6, and the reproduction process is performed.

FIG. 3 shows another embodiment of the present invention, in which a flow control gas port 48 is provided so as to supply a flow control gas in the exhaust direction. The basic operation is the same as in the previous embodiment, and a description thereof will be omitted.

In the above-described embodiment, the trap container 22 and the baffle plate are configured to have curved surfaces. However, a conventional baffle plate and a rectangular trap container as shown in FIGS. A flow control gas port may be provided in the trap device to facilitate the flow of exhaust gas to the trap section. Further, in this embodiment, the trap section is mechanically switched by providing a regeneration chamber for the regeneration process, but the trap section may be removed to perform regeneration at another location.

[0029]

As described above, according to the present invention, in a film forming process or the like, a certain amount of space inside the trap container is secured, and a stable operation is ensured without excessively lowering the conductance. The trap efficiency can be improved. Therefore, in a vacuum processing system using such a trap device, the life of the vacuum pump is extended and the abatement device is protected without affecting the performance of the vacuum pump, thereby improving the reliability of the operation. Equipment and operating costs as a whole can be reduced.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a trap device according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the trap device according to the first embodiment of the present invention.

FIG. 3 is a side sectional view of a trap device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a vacuum exhaust system provided with a trap device.

FIG. 5 is a diagram showing an example of a conventional trap device.

FIG. 6 is a view showing another example of a conventional trap device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum chamber 12 Vacuum pump 14 Exhaust pipe 22 Trap container 26 Air cylinder 30 Trap room 32 Regeneration chamber 38a, 38b, 38c Baffle plate 40a, 40b, 40c, 40d Trap channel 48 Flow control gas port

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[Procedure amendment]

[Submission date] January 26, 1998

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (5)

[Claims] 1. A trap device arranged in an exhaust pipe for exhausting air from a hermetic chamber by a vacuum pump, comprising: an airtight container constituting a part of the exhaust pipe; and a product disposed in the container and being exhausted. A trap portion for attaching and removing the trap portion, wherein the container is provided with a flow control gas port for flowing a flow control gas so as to promote a flow of exhaust gas toward the trap portion. Trap device. 2. The flow control gas port,
2. The flow control gas is provided to flow along an inner wall surface of the container.
3. The trap device according to claim 1. 3. The trap device according to claim 1, wherein the trap section has a baffle having a curved trap surface. 4. The trap device according to claim 3, wherein the trap surface is formed in a shape of a circular arc whose axis intersects the exhaust flow path. 5. The apparatus according to claim 1, wherein the trap section is provided so as to be able to be taken in and out of the container.
3. The trap device according to claim 1.