JP2001330367A - Device and process for solidifying and collecting gas, and method for detoxifying discharged gas using the device and/or process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a process capable of collecting gas used in a semiconductor manufacturing device or the like or generated gases that can not be collected by the prior art method, but discharged as they are. SOLUTION: Discharged gas discharged out of a vacuum chamber 1 is sucked by a vacuum pump 11 and fed into a cooling container 21 (22) through primary first and second valves 23 (25), 24 (25) under a low pressure condition. Inside part of the cooling container is set in a cryogenic state by a helium freezer 41. A plurality of fins 50 are fixed to a low temperature side 49 of a cylinder 48 of a cooling head 43 (44) of the freezer to perform a heat exchanging operation with surrounding gas, the gas is changed into solid, adhered to the fins and collected. The cooling container can be removed like a cassette type, the inside part of the removed cooling container is communicated with a high temperature incinerator, the gas is discharged into the incinerator, incinerated and decomposed into non-polluted substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for solidifying and trapping a gas for facilitating the removal of used harmful gas, and particularly to a harmful gas discharged into the atmosphere or a river. The present invention relates to an apparatus and a method for solidifying and capturing harmful gas components such as CFCs. Furthermore, the present invention relates to a harmful gas elimination treatment method in which harmful gases such as chlorofluorocarbons are solidified and supplemented, and then harmful gases are eliminated.

[0002]

2. Description of the Related Art In recent years, various reactive gases have been used in various apparatuses such as semiconductor manufacturing apparatuses, and some of these gases are directly discharged into the atmosphere in terms of safety, environmental pollution, global warming, and the like. Some have problems. An example is Freon gas. Therefore, these gases are subjected to a predetermined treatment after use and are exhausted.

FIG. 3 shows a schematic configuration of a gas processing apparatus used in a semiconductor manufacturing apparatus as an example of a conventional gas abatement apparatus.

In FIG. 1, reference numeral 101 denotes a vacuum chamber. In this example, an etching process for forming an electrode on a silicon substrate is performed in the chamber 101, and a silicon substrate Si is housed in the chamber 101 under vacuum. ,
HBr, Cl ₂ , CxFy is introduced into the chamber 101.
(Xy is an integer).

[0005] A vacuum pump 103 is connected to the vacuum chamber 101 via a valve 102. Vacuum pump 1
03, a predetermined degree of vacuum is established in the chamber 101 before the processing in the vacuum chamber 101 is started, and used gas or the like is sucked from the vacuum chamber 101 as exhaust gas after the processing is started. 104. At that time, N ₂ gas is supplied as a diluting gas to the vacuum pump 103, and the exhaust gas from the vacuum chamber 101 is diluted to a concentration of 1 to 3% on a nitrogen gas basis and sent to the detoxification processing apparatus 104.

[0006] The detoxification apparatus 104 is divided into two steps, and the first detoxification apparatus 105 is the first processing chamber 1.
And a vacuum chamber 1 diluted with nitrogen gas as described above through the vacuum pump 103 to the chamber 106.
The exhaust gas from 01 is sent in. In the chamber 106, a part of the component gas contained in the exhaust gas thus reacted reacts with the residual moisture in the chamber 106 to form SiO ₂ ,
Converted to HF, HCl, etc. And the vacuum chamber 101
The temperature of the exhaust gas, which was 800 ° C. to 900 ° C. in the first processing chamber 106, is reduced to about 60 ° C. to 70 ° C., whereby some gas components are solidified and recovered later.

[0007] The detoxification processing apparatus 104 is the first detoxification processing apparatus 1
A second detoxification treatment apparatus 107 is provided at a stage subsequent to 05 and exhaust gas that has not been solidified in the first treatment chamber 106 is sent into the second treatment chamber 108. In the second processing chamber 108, the sent exhaust gas is washed with water, various exhaust gases are confined in water, and discharged to a water treatment line (not shown), where a process for detoxification is performed.

However, the above-mentioned conventional detoxifying apparatus 10
4, the first detoxification processing apparatus 105 and the second detoxification processing apparatus 1
07, even with nitrogen, a chlorofluorocarbon-based gas having a significant effect on the global environment, such as chlorofluorocarbon 14 (C
F ₄ ), Freon 16 (C ₇ F ₆ ), Freon 23 (CHF
₃ ) Since gases such as those described above do not dissolve in water, harmless treatment of these gases is not performed, and the fact is that the gases are discharged into the atmosphere together with nitrogen gas. Various adverse effects have been pointed out, such as the promotion of global warming when Freon-based gas is released into the atmosphere, and it is necessary to suppress the release of these harmful exhaust gases to the atmosphere and rivers.

Further, for example, in a semiconductor manufacturing apparatus, various process gases are used in accordance with the processing contents in each manufacturing process, and it is necessary to change the detoxification processing apparatus in accordance with the used process gas.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been applied to a detoxification process of, for example, a fluorocarbon gas, which cannot be effectively performed by the conventional detoxification process. An object of the present invention is to provide an exclusion processing apparatus and a processing method which can be surely processed, and which can be applied regardless of the type of gas to be subjected to the detoxification processing.

[0011]

In order to solve the above-mentioned problems, an apparatus for solidifying and capturing a gas according to the present invention is provided with gas receiving means for receiving a supplied gas therein. A gas supply means supplies gas into the gas receiving means, and a cooling means for cooling the inside of the gas receiving means to a predetermined temperature or less is provided to cool the gas receiving means to a predetermined temperature or less. A predetermined gas component in the gas was solidified by exchanging heat with the surrounding gas to a solid trapping means provided therein, so that the solidified gas adhered.

The cooling means includes a compression unit that compresses helium gas using helium gas as a refrigerant, and a low-temperature section that adiabatically expands the compressed helium gas sent from the compression unit to generate cold heat. The low temperature section includes a cooling head disposed in the gas receiving means, and a pipe defining a passage between the compressed gas and the expanded gas between the compression unit and the cooling head. The solid capturing means is attached to the low temperature part of the cooling head so as to be able to conduct heat.

In one embodiment, the gas supply means has a function of reducing the pressure of the gas, and supplies the gas to the gas receiving means in a state where the degree of vacuum is not more than a predetermined degree.

Further, according to the present invention, there is provided an apparatus for solidifying and capturing a gas, comprising a container having pressure resistance and vacuum resistance for capturing the gas therein, and discharging the gas to be captured at a suction port side. A gas transfer device connected to the gas outlet of the device and connected to the container on the discharge port side, a cooling device for cooling the inside of the container to a predetermined temperature or less, and a predetermined gas in the gas provided in the container. A solid capturing member to which the components solidify and adhere.

The cooling device includes a compression unit for compressing the refrigerant gas, and a low-temperature part for generating a cool heat by adiabatically expanding the compressed refrigerant gas, and at least the low-temperature part located in the container. A head and a pipe defining a refrigerant gas passage between the compression unit and the cooling head.

In one embodiment, the gas transfer device is constituted by a vacuum pump, and transfers the gas into the container under a predetermined pressure or less.

In still another embodiment, the container is of a cassette type, and can be detached from the gas solidification capturing device in a sealed state.

Further, a plurality of cassette-type containers can be mounted simultaneously and in parallel, and the plurality of containers can be sequentially switched and used.

Further, the gas solidification capturing device is provided with a gas discharge device for discharging a gas that does not solidify in the container from the container.

Further, a plurality of fins are attached to the low-temperature portion located in the container, and when heat is exchanged through the fins, the gas is solidified and adheres to the fins.

[0021] In order to solve the above problems, a method for supplementing solidification of a gas according to the present invention includes the following steps. That is, a step of sending gas discharged from a semiconductor manufacturing apparatus or the like at a predetermined pressure or less into a pressure-resistant and vacuum-resistant container, and cooling the inside of the container to a predetermined temperature or less, and This is a step of solidifying and capturing a predetermined gas component in the gas.

In order to solve the above-mentioned problems, the method for removing exhaust gas according to the present invention is directed to a method for removing gas discharged from a semiconductor manufacturing apparatus or the like in a pressure-resistant and vacuum-resistant container under a predetermined pressure or less. Sending the container, cooling the inside of the container to a predetermined temperature or less, solidifying and trapping the sent gas, removing the container in a sealed state, and thereafter, setting the inside of the container to a predetermined temperature. The method includes a step of communicating with the incinerator for heating and incineration, causing the trapped gas to flow out into the incinerator, incinerating it, decomposing it into harmless components, and removing the harmful components.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the scope of the present invention is not limited to the embodiments described below.

FIG. 1 is a schematic diagram showing a configuration of a gas solidification trapping device 10 according to an embodiment of the present invention. In the drawing, the device 10 is a semiconductor manufacturing apparatus described in relation to the above-mentioned conventional example. 1 is connected to a vacuum chamber 1 for performing an etching process for forming an electrode on a silicon substrate. As described above, HBr, Cl _2, FxFy, and the like are supplied into the vacuum chamber 1, and the etching process is performed under plasma discharge. The vacuum chamber 1
It is connected to the device 10 via the valve 2. As this valve 2, it is desirable to use a vacuum valve that does not leak under vacuum pressure.

Reference numeral 11 denotes a vacuum pump used in the conventional example. As described in the conventional example, the vacuum pump 11 establishes a predetermined degree of vacuum in the chamber 1 before the processing in the vacuum chamber 1 is started. After the processing in the chamber 1 is started, the gas used in or generated in the chamber 1 is sucked and sent to a cooling and solidifying device 20 described below under a low pressure. The same ones can be used. Note that nitrogen gas is supplied to the vacuum pump 11,
The point of diluting the gas from the vacuum chamber 1 is the same as the conventional one.

As will be described later, the cooling and solidifying device 20 includes a cooling container for cooling and solidifying various harmful gases including a fluorocarbon-based gas sent from the vacuum chamber 1. Containers 21 and 22 are provided.
These cooling containers 21 and 22 have a very strong pressure-resistant structure capable of withstanding a very high degree of vacuum and pressure, and have a structure excellent in heat insulation.

The containers 21 and 22 are connected in parallel to the vacuum pump 11 via primary side first valves 23 and 24 on the pump side and primary side second valves 25 and 26 on the container side. The first valves 23 and 24 are desirably vacuum valves. It is desirable that the second valves 25 and 26 be vacuum high-pressure valves that can withstand vacuum and also withstand high pressure. The second valves 25 and 26 are attached in a state of being integrated with the cooling vessels 21 and 22, respectively.
The first valves 23 and 24 can be separated from each other.

Valves 25 and 26 of cooling containers 21 and 22
On the opposite side, transport pumps 27 and 28 are integrally attached. The transport pumps 27 and 28 discharge harmless gases such as hydrogen and nitrogen that are not solidified in the cooling containers 21 and 22 from the containers 21 and 22.

Downstream of the transport pumps 27 and 28, the first secondary valves 29 and 30 and the second secondary valves 3
1, 32 are connected in this order. First valve 2
9 and 30 are integrally attached to the transport pumps 27 and 28, respectively, and can be separated from the second valves 31 and 32. The first valves 29, 30 are desirably vacuum high pressure valves.

At the downstream side of the secondary second valves 31 and 32, the two lines join, and in this embodiment, a blower 33 as an exhaust transportation pump is provided there. The blower 33 is moved by the transport pumps 27 and 28 to the cooling vessel 2.
This is for sending nitrogen, oxygen, and the like discharged from 1, 22 to the outside of the system.

The cooling and solidifying device 20 comprises cooling containers 21 and 2
2 is provided with cooling means for cooling and solidifying, for example, a chlorofluorocarbon gas. Specifically, the cooling means in the present embodiment includes a helium refrigerator 41 using helium gas. More specifically, in the present embodiment, the helium refrigerator 41 is a refrigerator using a so-called GM cycle. Cooling heads 43 and 44, compressor unit 42 and each head 4
High pressure side pipe 45 and low pressure side pipe 4 connecting between
6 is provided. The compressor unit 42 compresses the helium gas while cooling it to a high pressure.
3 and 44, and the high-pressure helium gas is adiabatically expanded in the low-temperature portions of the heads 43 and 44 to generate a low temperature. The gas expanded and released is collected again by the compressor unit 42 and compressed. This GM
A helium refrigerator using a cycle is known, and in the present invention, the known refrigerator can be used, and a detailed description thereof will be omitted. In the present embodiment, the connection between the heads 43 and 44 and the pipes 45 and 46 is detachably connected by a spring valve (not shown). When this connection is cut off, both connection parts are sealed. Becomes

FIG. 2 is a diagram schematically showing the internal structure of one cooling container 21, and the other cooling container 22 has the same structure. Therefore, only the cooling container 21 will be described.

A pair of cooling heads 43 are provided for the cooling vessel 21.
The first and second secondary valves 25 and 27 extend in a direction substantially perpendicular to the direction in which the gas flows in the container 21, ie, the direction in which the gas flows in the container 21, and are integrally attached to each other. And the cylinder 47 is used for the cooling container 21.
It extends inside. The tip of the cylinder 47 is a low temperature section 48, where a low temperature is generated.

A fin attachment shaft 49 extending in a direction substantially perpendicular to the fin attachment shaft 49 is integrally attached to the low-temperature end portion 48 of the cylinder 47, and a plurality of fins 50 are attached to the attachment shaft 49 at predetermined intervals as shown in the figure. Have been. Therefore, the low temperature or cold generated in the low temperature section 48 cools the fins 50 to bring the inside of the container 21 to a very low temperature state. Naturally, the fins closer to the low temperature section 48 are cooled.

In the gas solidification trapping device 10 configured as described above, the two lines provided with the cooling vessels 21 and 22 are used alternately and operate as follows. That is, first, the line provided with the cooling vessel 21 is used, and in this case, the valves 24, 26,
30 and 32 are closed, and the communication between the compressor unit 42 of the refrigerator 41 and the cooling head 43 is also cut off.
Alternatively, the space between the valves 24 and 26, the space between the valves 30 and 32, and the space between the pipes 45 and 46 and the head 44 may be cut off, and the cooling container 22 may be removed.

First, the secondary first and second valves 29, 31
Is opened, and the blower 33 is started with the primary side first and second valves 23 and 25 closed. Then, the transport pump 27 is started, and the inside of the cooling container 21 is exhausted. On the other hand, the refrigerator 41
Starts the operation, and cools the inside of the cooling container 21. The cooling container 21 is provided with a temperature sensor (not shown), and the processing in the vacuum chamber 1 cannot be started until the inside of the container 21 reaches, for example, 15K.

When the temperature in the cooling container 21 reaches a predetermined temperature, the valve 2 is opened, and the first and second primary side valves are opened.
The valves 23 and 25 are also opened, and the vacuum pump 11 starts. When the inside of the vacuum chamber 1 is set to a predetermined vacuum pressure by the vacuum pump 11, the above-described reactive gas is sent into the vacuum chamber 1 at a predetermined flow rate, and the processing in the vacuum chamber 1, for example, the etching processing in the present embodiment. Is started. The gas in the vacuum chamber 21 is sucked by the vacuum pump 11 and sent into the cooling container 21 at a low pressure through the primary first valve 23 and the second valve 25.

The gas sent into the cooling container 21 is:
Since the inside of the cooling container 21 is at an extremely low temperature as described above, it is instantaneously cooled when
It adheres to and solidifies. The closer the fin 50 is to the low temperature section 48, the lower the temperature. Therefore, the fins near the inlet of the container 21 near the primary second valve 25 are easily solidified even at a relatively high temperature, for example, Cl ₂ , HF, Br ₂
Etc. adhere and solidify. On the other hand, although the CFC-based gasification is extremely difficult to solidify, the refrigerator 41 used in the present embodiment is used.
Uses helium gas as a refrigerant, and has a structure in which a low-temperature part is provided with a two-stage expansion chamber so that an extremely low temperature of 15 K or less can be obtained. Since the temperature of the fluorocarbon-based gas is low enough to be solidified, it is captured by the fins near the low-temperature portion 48 and solidified. Note that helium, nitrogen, oxygen, and the like are harder to solidify and are not trapped.
7. The air is discharged into the atmosphere by the blower 33, but since these do not adversely affect the environment, they can be safely used. The gas that does not solidify in this way is exhausted from the cooling container 21, while the harmful gas including fluorocarbons and other gases are discharged from the container 2.
Since the solidification occurs in the container 1, the inside of the container 21 is established at a very high degree of vacuum, which also promotes the solidification of the gas.

As the amount of adhesion to the fins 49 increases, the heat exchange efficiency at the fins 50 decreases. Accordingly, the temperature in the chamber 21 increases. When the temperature sensor detects that the temperature in the container 21 has risen to a predetermined value, for example, 20K, the operation of this device is stopped.

Here, a predetermined closing operation of each valve is performed.
The container 21 is removed from the device. On the other hand, the line provided with the other cooling container 22 is operated, and the processing is restarted.

The container 21 on the removed side is connected to an incinerator for incineration at a temperature of, for example, 1400 ° C. or more, using the second valve 25 on the primary side. Then, the valve 25 is opened and the gas trapped inside is released into the incinerator, and all the gas is incinerated and decomposed. CFCs decompose at temperatures above 1400 degrees C and turn harmless to the environment. The chamber 21 is connected to the device 1
When removed from 0, the cooling action on it stops,
As a result, the temperature rises, and the gas that has solidified inside may evaporate again, increasing the pressure. However, there is no problem because the cooling chamber 21 has a structure that can withstand high pressure. Further, since the container 21 itself is excellent in heat insulation, the temperature rise itself is relatively small.

Here, those which can be solidified and captured by the gas solidification capturing apparatus according to the present invention include Freon 14, Freon 116, Freon 23, etc. as Freon-based gases, and Freon 13, Freon 22, Freon 12 and the like. , Freon 114,
Freon 11, Freon 113, and the like. And according to the present invention, not limited to fluorocarbons, for example, silane, dichlorosilane, silicon tetrachloride, phosphine, arsine, diborane,
Processing of phosphine, alhin, etc. is also possible.

In the above description, a helium refrigerator using helium gas has been described, but the cooling means is not limited to this. Any refrigerant capable of providing a low temperature to solidify the gas to be trapped may be used.

[0044]

As described above, according to the present invention, in a reactive gas used in a semiconductor manufacturing apparatus or a gas generated during processing, a safety or environmental adverse effect may be caused. Regardless, the conventional treatment method allows the CFC-based gas to be solidified and trapped, for example, without being trapped and released to the atmosphere without being trapped, thereby enabling detoxification treatment in a high-temperature incinerator or the like.

Further, since the solidification is performed at an extremely low temperature, it is effective for most gases. Therefore, the same solidification trapping device can be used even if different reactive gases are used, which is very convenient.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a gas solidification capturing device of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a cooling container shown in FIG.

FIG. 3 is a schematic diagram illustrating a configuration of an example of an abatement apparatus used in a conventional semiconductor manufacturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Valve 10 Gas solidification capture device 11 Vacuum pump 20 Cooling solidification device 21,22 Cooling container 23,24 Primary first valve 25,26 Primary second valve 27,28 Transport pump 29,30 Secondary Side first valve 31, 32 Secondary side second valve 33 Blower 41 Helium refrigerator 42 Compression unit 43, 44 Cooling head 47 Cylinder 48 Low temperature section 50 Fin

Claims (12)

[Claims] 1. An apparatus for solidifying and capturing a gas, a gas receiving means for receiving a supplied gas therein, a gas supply means for supplying a gas into the gas receiving means, and the gas receiving means Cooling means for cooling the inside of the means to a predetermined temperature or less, and provided in the gas receiving means and solidifying a predetermined gas component in the gas by heat exchange with surrounding gas, and the solidified gas is An apparatus for capturing and solidifying a gas, comprising: a solid capturing means for adhering. 2. The apparatus according to claim 1, wherein the cooling unit generates a cold heat by adiabatically expanding the compression unit that compresses the helium gas and the compressed helium gas sent from the compression unit. A cooling head disposed at least in the gas receiving means, and defining a passage between the compressed gas and the expanded gas between the compression unit and the cooling head. And a solid pipe, wherein the solid capturing means is attached to the low-temperature portion so as to be able to conduct heat,
Gas solidification capture device. 3. An apparatus according to claim 1, wherein said gas supply means supplies said gas to said gas receiving means in a state where said gas is kept at a predetermined degree of vacuum or less. Capture device. 4. A device for solidifying and trapping gas, comprising: a container having pressure resistance and vacuum resistance for trapping gas therein; and a gas for discharging gas to be trapped at a suction port side. A gas transfer device connected to the discharge port and connected to the container on the discharge port side, a cooling device for cooling the inside of the container to a predetermined temperature or less, and provided in the container,
A solid capturing member to which a predetermined gas component in the gas is solidified and adheres. 5. The apparatus according to claim 4, wherein the cooling device includes a compression unit that compresses the refrigerant gas, and a low-temperature portion that generates a cold heat by adiabatically expanding the compressed refrigerant gas, and A cooling head in which a low-temperature part is located in the container; and a pipe defining a passage of a refrigerant gas between the compression unit and the cooling head. Capture device. 6. The device according to claim 4, wherein
The gas transfer device is a vacuum pump, and transfers the gas into the container at a pressure equal to or lower than a predetermined pressure. 7. The apparatus according to claim 4, wherein the container is detachably provided in a sealed manner in a cassette manner from the gas solidification capturing device. Gas solidification capture device. 8. The apparatus according to claim 7, wherein a plurality of said containers can be simultaneously attached to said gas solidification capturing device in parallel, and said plurality of containers can be sequentially switched and used. A gas solidification trapping device, characterized in that: 9. The apparatus according to claim 4, wherein the gas solidification capturing device further includes a gas discharge device that discharges a gas that does not solidify in the container from the container. A gas solidification supplementary device, characterized in that: 10. The apparatus according to claim 4, wherein a plurality of fins are attached to the low-temperature part located in the container, and heat is exchanged via the fins, whereby the heat is exchanged. A gas solidification capturing device, wherein gas is solidified and adheres to the fin. 11. A gas discharged from a semiconductor manufacturing apparatus or the like is fed into a pressure-resistant and vacuum-resistant container at a predetermined pressure or lower, and the inside of the container is cooled to a predetermined temperature or lower, and A method for solidifying and capturing a gas, comprising solidifying and capturing a predetermined gas component in a collected gas. 12. A gas discharged from a semiconductor manufacturing apparatus or the like is sent into a pressure-resistant and vacuum-resistant container at a predetermined pressure or lower, and the inside of the container is cooled to a predetermined temperature or lower, and Solidifying and trapping the trapped gas, removing the container in a sealed state, communicating the inside of the container with an incinerator that heats and incinerates the container at a predetermined temperature or higher, and incinerate and harm the trapped gas. Characterized by the exhaust gas elimination method.