JP3162650B2 - TRAP DEVICE AND ITS REPRODUCING METHOD - Google Patents

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, for example, a semiconductor manufacturing apparatus, and a method for regenerating the trap device.

[0002]

2. Description of the Related Art A conventional vacuum pumping system will be described with reference to FIG. Here, the vacuum chamber 101 is
For example, it is a process chamber used for a semiconductor manufacturing process such as an etching apparatus and a chemical vapor deposition apparatus (CVD). The vacuum chamber 101 is connected to a vacuum pump 103 through a pipe 102. The vacuum pump 103 is for increasing the pressure of the exhaust gas of the process from the vacuum chamber 101 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 101 is higher than the ultimate degree of vacuum of the dry pump 103,
An ultra-high vacuum pump such as a turbo-molecular pump may be further arranged upstream of the dry pump. The exhaust gas of the process is toxic or explosive depending on the type of process,
It cannot be released to the atmosphere as it is. Therefore, the vacuum pump 1
An exhaust gas treatment device 104 is provided downstream of the apparatus 03. Among the exhaust gas of the process whose pressure has been increased to the atmospheric pressure, those which cannot be released to the atmosphere as described above are subjected to treatment such as adsorption, decomposition, absorption and the like, and only harmless gas is released to the atmosphere. The pipe 102 is provided with a valve at an appropriate position as needed.

[0004]

In the conventional vacuum evacuation system described above, 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 the gas solidifies and precipitates in the vacuum pump, which causes a failure of the vacuum pump. For this reason, it is conceivable to provide a water-cooled trap section upstream (intake side) of the vacuum pump in the exhaust path to trap precipitates.

In this case, an amount of deposits corresponding to the amount of exhaust gas is deposited on the trap portion, and the deposits contain substances that are harmful when vaporized or expensive, so it is better to reuse them. Good things are mixed. Therefore, in order to reuse the trap portion by reusing the precipitate itself and detoxifying or collecting the precipitate, it is desired to perform a regeneration treatment for separating or removing the precipitate in the trap portion.

Conventionally, in such an exhaust gas regenerating treatment, the trap portion is heated to a high temperature to gasify the precipitate in the trap portion and regenerated, or the trap portion is moved to another place and neutralized here. This was commonly done by washing.

[0007] However, in the former case, if the sublimation temperature is high, the trap section must be heated to a temperature higher than the sublimation temperature. If this is done, the low-temperature part and the high-temperature part will be adjacent to each other, leading to a significant energy loss. Furthermore, regeneration treatment by sublimation generally requires a longer time than trap treatment, so that work efficiency is poor and a large container for storage is required in order to reuse recycled gas after vaporization. You will need it.

On the other hand, in the case of the latter, not only is it necessary to remove the trap portion and move it to the washing position, but also it is necessary to separately store the removed trap portion and other operations.
Workability is quite bad. In addition, there is a problem that it is necessary to prepare a large number of trap portions in advance and replace them.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and efficiently and promptly regenerates a trap portion to extend the life of a vacuum pump and an exhaust gas treatment device of an exhaust system and to improve the reliability of operation. Another object of the present invention is to provide a trap device capable of improving safety and safety, and further reducing equipment and operating costs, and a method for regenerating the trap device.

[0010]

According to a first aspect of the present invention, there is provided a trap device having a trap portion disposed in an exhaust path for exhausting a gas from a hermetic chamber by a vacuum pump and attaching and removing components in exhaust gas. A regeneration gas discharge path is provided adjacent to the exhaust path for gasifying and discharging the deposits attached to the trap section under reduced pressure,
Switching means for switching the trap section between the exhaust path and the regeneration gas discharge path is provided.

[0011] This makes it possible to regenerate by depositing gas adhering to the trap portion without reducing the temperature and cleaning the trap portion without raising the temperature or cleaning the device. Moreover, safety can be improved. It is also easy to achieve complete automation by using an appropriate switching timing determination unit.

The airtight chamber is, for example, a process chamber of a semiconductor manufacturing apparatus, and is provided with an exhaust gas treatment device for detoxifying a process gas as required. As the vacuum pump, it is preferable to use a dry pump that does not use lubricating oil in order to prevent contamination of the chamber due to back diffusion by oil.

The switching of the trap portion may be performed by an air cylinder. In that case, control may be performed by an air drive control device including a solenoid valve and a speed controller, and further, the air drive control device may be controlled by a control signal from a sequencer or a relay. .

As a method of completely automatically switching the trap portion without manual operation, for example, a sensor for detecting a differential pressure before and after the trap portion is provided and the detected value is set to a predetermined value. There is a method in which switching is performed when this happens, or a more practical method in which an appropriate switching time is set in advance. When the exhaust gas circulation path and the regenerated material discharge path are one-to-one, the trap and regeneration times are the same. Therefore, the regeneration capacity should be higher than the trap capacity so that the regeneration end time is shorter. Is preferred.

According to a second aspect of the present invention, in the vacuum evacuation system according to the first aspect, the trap device is a low-temperature trap that cools the trap portion to precipitate the components.

When the trap section is configured as a low-temperature trap, there is a method in which a temperature medium is circulated from the outside to the trap section, such as heat of vaporization of liquefied gas (for example, liquid nitrogen), cooling water, and refrigerant. There is also a method of generating a low temperature in the trap portion without flowing the temperature medium itself using a thermoelectric element (Peltier element), a pulse tube refrigerator, or the like.

[0017] Prior Symbol regeneration gas discharge path, a plurality of reproduction gas trap to trap deposits for each component may be provided in parallel. Thereby, the components in the regeneration gas can be deposited and stored in each regeneration gas trap container for each substance, so that the processing and reuse can be facilitated.

The invention described in claim 3, wherein the switching means is in the trap apparatus according to claim 1, characterized in that the trap portion is to move to the exhaust path and the regeneration gas discharge path Therefore, switching is performed quickly and operation efficiency is high.

According to a fourth aspect of the present invention, the switching means switches the trap section between the exhaust path and the regeneration gas discharge path by operating a valve. Since it is a device, no mechanical switching drive means is required, and the equipment can be downsized.

According to a fifth aspect of the present invention, the components trapped by a trap device which is disposed in an exhaust path for exhausting the components from the airtight chamber by a vacuum pump and has a trap portion for attaching and removing components in the exhaust gas are regenerated. In the regeneration method, the deposits attached to the trap portion are gasified by substance under reduced pressure, and the gasified regeneration gas is transferred to each regeneration gas trap container for each substance and precipitated again in the container. It is a regeneration method of the trap device.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 5 show a vacuum exhaust system using the trap apparatus of the present invention. A regeneration gas exhaust path 16 is arranged adjacent to an exhaust path 14 for exhausting the airtight chamber 10 by a vacuum pump 12. A trap body 20 is provided so as to straddle both the exhaust path 14 and the regeneration gas discharge path 16. An exhaust gas treatment device 24 for removing exhaust gas is provided downstream of the vacuum pump 12 in the exhaust path 14.

The trap body 20 includes a casing 26
The trapping chamber 32a and the regenerating chamber 34a formed therein, and the exhaust path 1 is provided between the trap chamber 32a and the regenerating chamber 34a.
4 and a trap portion 18 movable in a direction intersecting the regeneration gas discharge path 16.

The exhaust gas discharge path 16 has a pressure adjusting valve 96 for adjusting the pressure in the regeneration chamber 34a, and further branches downstream into three paths 16a to 16c. In each path, a switching valve 98 which is opened alternatively is provided.
a to 98c and regeneration gas trap containers 22a to 22c are provided and connected to the regeneration vacuum pumps 13a to 13c. The regeneration vacuum pumps 13a to 13c are individually operated, and are operationally controlled so that the pressure inside the regeneration chamber 34a is gradually reduced.

FIGS. 2 and 3 show the trap body 20, which includes an exhaust path 14 and a regeneration gas discharge path 16.
, A shaft body 28 penetrating the casing 26 in the cross direction, and an air cylinder 30 as switching means for reciprocating the shaft body 28 in the axial direction. The casing 26 has a trap container 32 whose inside is a trap chamber 32a and a regeneration container 34 whose inside is a regeneration chamber 34a.

The trap container 32 is provided with an exhaust gas inlet 32b connected to the exhaust path 14 for introducing exhaust gas into the trap chamber 32a and an exhaust gas outlet 32c for discharging exhaust gas in the trap chamber 32a. . The regeneration container 34 has an opening 34b for releasing the internal pressure.
And a suction port 34c for sucking the inside of the regeneration chamber 34a.

A pair of seal plates 40 made of a heat insulating material are disposed on the shaft 28, and a plurality of baffle plates 42 are integrally attached to the shaft 28 by welding or the like in order to improve heat conduction. The trap section 18 is configured. On the side adjacent to the trap container 32 and the regeneration chamber 34, an opening 36 having a size such that the baffle plate 42 can pass but the seal plate 40 cannot pass is provided. Furthermore,
Bellows 44 are provided on both protruding portions of the shaft body 28 from the casing 26, and the exhaust path 14 and the regeneration path 1 are provided.
6 and the external environment are kept airtight.

[0027] The total of four places of the inner surface facing opposite sides of the opening 36 of the trap container 32 and the opening 36, the seal plate accommodating section 46 formed in a shape along the outer shape of the sealing plate 40 Is provided. The seal plate 40 is formed of a material having high heat insulating properties, and includes a trap chamber 32a and a regeneration chamber 34a.
The outer peripheral end surface is formed in a circular cross section, and the seal portion 4
8 are provided. The sealing portion 48 is provided on the sealing plate 4.
The O-ring 50 is formed by fitting an O-ring 50 as a sealing material into a concave portion 40 a provided on the outer peripheral end surface of the O-ring 50. The inner peripheral surface 46 is pressed against the inner peripheral surface. Here, the inner peripheral surface of the seal plate housing portion 46 is formed in a tapered shape so that the seal plate 40 can easily enter.

Further, a second seal portion 52 is provided on one of the side end surfaces of the seal plate 40 or one of the wall surfaces of the seal plate storage portion 46 with which the side end surface abuts. In this example, the second seal portion 52 is provided on one end surface of one seal plate 40.
An example is shown in which two seal portions 52 are provided in two seal plate storage portions 46, respectively. That is, in the seal plate 40, a ring-shaped concave portion 40b is provided on the side end surface thereof, and the O-ring 54 is fitted in the concave portion 40b. A second seal portion 52 is formed by providing a ring-shaped concave portion 46a in the concave portion and fitting an O-ring 54 into the concave portion 46a.

As described above, the sealing plate 40 and the casing 2
6 (the trap container 32 and the regeneration container 34) is double-sealed at the outer peripheral end face and the side end face of the seal plate 40, thereby assuring the integrity of the seal here and the exhaust path 14
And the airtightness of the reproduction path 16 is maintained.

The shaft 28 is formed as a double cylinder made of a material having good heat conductivity such as metal, and the refrigerant supplied from the refrigerant supply pipe 56 passes through the inside of the pipe inside the shaft 28. After that, it flows through the gap between the two pipes and is discharged from the refrigerant discharge pipe 58, whereby the baffle plate 42 is cooled. Here, as the refrigerant, for example, a liquid such as liquid nitrogen or cooled air or water is used. At the time of regeneration, the supply of the refrigerant may be stopped, and a heating heat medium for regeneration may be circulated instead of the refrigerant.

The regeneration gas trap containers 22a to 22c
As shown in FIG. 4, a regeneration gas inlet 60 formed into a relatively large-capacity box and communicating with the regeneration gas discharge path 16 (see FIG. 1) to introduce the regeneration gas therein, and a regeneration vacuum pump An exhaust port 62 communicating with 13a to 13c (see FIG. 1) is provided, and a caster 64 for movement is attached to the bottom. Further, a hollow cooling pipe 66 through which a coolant such as liquid nitrogen flows is disposed, and a number of baffle plates 68 are integrally attached to the cooling pipe 66 at a predetermined pitch along the axial direction by welding or the like. I have.

As described above, by trapping and storing the regeneration gas in the regeneration gas trap containers 22a to 22c having a relatively large capacity, the replacement cycle can be lengthened,
For example, by transferring the regenerated gas trap containers 22a to 22c which are full of the exhaust gas component to a waste disposal company, it is possible to easily perform this processing such as reuse.

Instead of flowing a refrigerant such as liquid nitrogen,
As shown in FIG. 6, for example, the cooling pipe 66 may be cooled by a refrigerator 70 such as a helium refrigerator, and the baffle plate 68 thermally connected to the cooling pipe 66 may be cooled.

The air pipe for driving the air cylinder 30 is as shown in FIG. That is, the air from the air source is depressurized by the regulator 80, sent to the solenoid valve 82, and controlled to be opened or closed by an electromagnetic signal, sent to the cylinder 30, and the piston moves forward or backward. The driving speed of the cylinder 30 at this time is controlled by the speed controller 84. In this example, the solenoid valve 82 is controlled by a control signal from a sequencer, a relay, or the like so that the switching operation is performed at regular intervals.

A temperature sensor 90 is provided at a predetermined position such as the baffle plate 42 of the trap section 18, and a pressure sensor 92 is provided before and after the trap section 18 of the exhaust path 14, thereby detecting a temperature and a differential pressure. You can do it.

The operation of the thus configured trap device of the embodiment of the invention will be described. In the position shown in FIG.
A coolant such as liquid nitrogen, cooling air, or water is supplied from a coolant supply pipe 56 to the trap portion 18 located in the trap chamber 32a, and the coolant is supplied to the shaft 28 and the baffle plate 4 via the shaft 28.
Cool 2 Therefore, specific components in the exhaust gas that come into contact therewith are deposited here, adhere to them, and are trapped.

After a lapse of a predetermined time, the air cylinder 30 operates to switch the trap portion 18 in the trap chamber 32a so as to be located in the regeneration chamber 34a, as shown in FIG. Here, the regeneration vacuum pumps 13a to 13c are sequentially activated one by one to reduce the pressure in the regeneration chamber 34a to preset different pressures. First, only the valve 98a of the first regeneration gas discharge path is opened and the regeneration vacuum pump 1 is opened.
At 3a, the pressure inside the regeneration chamber 34a is reduced to the first set pressure. As a result, of the precipitates trapped in the trap portion 18, relatively easily vaporized components are vaporized in the regeneration chamber 34a, and the vaporized regeneration gas is supplied to the regeneration gas discharge path 16
a and 16 to the regeneration gas trap container 22a.

[0038] Then, the regeneration gas, the reproduced gas trap 22 a in a cooled again trapped in the baffle plate 68, the gas after the trap regeneration vacuum pump 1
3a is discharged to the outside. Next, when this component is sufficiently regenerated, the switching valve 98a is closed, 98b is opened, and the regenerating chamber 34a is depressurized to a second pressure lower than the first set pressure by the regenerating pump 13b. As a result, the components vaporized at this pressure are regenerated, and the regenerated gas trap container 2
It is led to 2b and stored. Thereafter, similarly, the pressure of the regeneration chamber 34a is reduced to a third pressure lower than the second set pressure by the third regeneration pump 13c, and the component which is hardest to vaporize is regenerated, and is led to the regeneration gas trap container 22c. Can be stored.

In this manner, the trapped deposits are separated according to their components, and are separated into the respective regeneration gas trap containers 2.
2a to 22c. Regeneration gas trap container 22
When a to 22c are full of stored components, they are replaced with new ones, and are respectively sent to predetermined processes such as reuse and disposal.

Here, since both the protruding portions of the shaft body 28 are kept airtight by the bellows 44 which expand and contract, energy loss due to heat transfer to the outside and a reduction in processing efficiency are suppressed, and a stable trap is formed. The regeneration process is also performed, and the contamination element from the outside is prevented from entering the regeneration gas discharge path 16.

As a cooling means for the trap,
Thermoelectric element that cools by thermoelectric effect (Peltier element)
It is a matter of course that a cooler using the above may be used. This type of cooler is constructed by placing a thermoelectric element at a distance between two metal plates. In this embodiment, an example is shown in which three regeneration gas trap containers are provided in parallel, but it is needless to say that an appropriate number may be provided as needed.

[0042]

As described above, according to the present invention, the components trapped in the trap portion can be regenerated by reducing the pressure without heating the trap portion or using a cleaning liquid. Thereby, the scale of the apparatus can be simplified, and the cost of equipment can be reduced. In addition, by providing a plurality of regeneration gas discharge paths, exhaust gas can be collected and treated for each substance, and the processing can be performed according to the characteristics of the components, so that each processing can be performed efficiently and at low cost. It is easy to reuse.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a trap device according to one embodiment of the present invention.

FIG. 2 is a partially cutaway front view showing a trap body used in the embodiment of FIG. 1;

FIG. 3 is a front view of a partially cut state after switching of the trap body of FIG. 2;

FIG. 4 is a sectional view of a regeneration gas trap container used in the embodiment of FIG.

FIG. 5 is a diagram showing a drive system of an air cylinder.

FIG. 6 is a sectional view showing another example of the regeneration gas trap container.

FIG. 7 is a view showing the structure of a conventional evacuation system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum chamber 12 Main vacuum pump 13a, 13b, 13c Vacuum pump for reproduction | regeneration 14 Evacuation path 16 Regeneration gas discharge path 18 Trap part 20 Trap main body 22a, 22b, 22c Regeneration gas trap container 26 Casing 28 Shaft 30 Air cylinder (driving means) 32) Trap container 32a Trap chamber 34 Regeneration container 34a Regeneration chamber 42 Baffle plate 46 Seal plate storage part 48, 52 Seal part 66 Cooling pipe 68 Baffle plate 96 Pressure regulating valve 98a, 98b, 98c Switching valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F04B 37/16

Claims (4)

(57) [Claims] 1. A trap device disposed in an exhaust path for exhausting air from a hermetic chamber by a vacuum pump and having a trap section for attaching and removing components in exhaust gas, wherein the trap section is attached to the trap section adjacent to the exhaust path. deposits regeneration gas discharge path for discharging by gasification is provided by vacuum, the trap portion switching means for switching the regeneration gas exhaust path and the exhaust path provided with, on the regeneration gas discharge path, a deposit Gasification by substance
Multiple regeneration gas trap containers that trap each component
A trap device provided in a row . 2. The switching device according to claim 1 , wherein
It is moved to the exhaust path and regeneration gas discharge path
The trap device according to claim 1, wherein: 3. The switching means includes :
Switching to exhaust path and regeneration gas discharge path by operating a valve
2. The trap according to claim 1, wherein
apparatus. 4. Evacuation from a hermetic chamber by a vacuum pump
Is placed in the exhaust path,
Before captured by a trap device with a trap section to be removed
In the regeneration method for regenerating the above-mentioned components, the deposits adhering to the trap portion are separated into
And regenerate this gasified regeneration gas by substance.
Transfer to a gas trap container and allow it to precipitate again in the container.
And a method for regenerating a trap device.