KR20100032674A - Method and apparatus for treating process gas - Google Patents

Abstract

PURPOSE: A method for treating and processing gas and a treatment device thereof are provided to improve economical efficiency and to recycle used catalysts for other uses while improving environmental friendliness. CONSTITUTION: A method for treating and processing gas includes a step for forming exhaust gas including carbon dioxide by decomposing processed gas with plasma and a step for adsorbing the carbon dioxide in the exhaust gas with materials activated by the plasma. A treatment device includes a reactor(200) forming the exhaust gas including the carbon dioxide and an exhaust line(220) discharging the exhaust gas decomposed by the reactor.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for treating gas,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process gas treating method and a treatment apparatus, and more particularly, to a process gas treating method and a treatment apparatus which decompose a fluorine-containing process gas generated after a semiconductor process by a plasma and effectively adsorb CO ₂ generated on the plasma- The amount of CO ₂ in the exhaust gas can be reduced to a considerable level, so that it is not only economical but environmentally friendly, and further, the catalyst used can be reused for other purposes without a separate regeneration process. will be.

In the semiconductor process, various process gases such as NF ₃ and CF ₄ are widely used for various processes such as etching. Since the gas used in the process is very toxic, it must be treated in a harmless form before it can be discharged directly to the atmosphere.

One of the methods for decomposing fluorine compounds such as PFC or HFC, which is harmful, is a method of directly hydrolyzing a fluorine compound. This method converts fluorine in a fluorine compound into hydrogen fluoride (HF) by adding water to the gaseous fluorine compound and reacting them, so that the fluorine compound is easily absorbed into a water or alkali aqueous solution.

One example of the above technique is disclosed in Korean Patent Application 2001-7011666 (hereafter referred to as a reference).

The cited technology is _{C 2 F 6, CF 4,} CHF 3, SF 6, NF 3 fluorine compound to the fluorine compound in the presence of water or water and oxygen, such as cracking catalyst, and CO, SO ₂ F one of ₂ and N ₂ O Or more. The catalyst for decomposing at least one of CO, SO ₂ F ₂ and N ₂ O preferably contains at least one selected from the group consisting of Pd, Pt, Cu, Mn, Fe, Co, Rh, do.

However, the above-mentioned citation technique is a method of releasing CO ₂ generated by a method of contacting carbon monoxide (CO) with an oxidation catalyst in an atmospheric state. In this case, emitted CO ₂ causes global warming and the like. The above problem has been a relatively overlooked problem, but it is significant to remove CO ₂ from the exhaust gas at the present time when the emission rights of greenhouse gases according to the Kyoto Climate Convention have been allocated below a certain level between the state and the enterprises.

In addition, since the harmful component removing catalyst is made of a relatively expensive metal, the process economical efficiency is lowered, and the used catalyst is substantially discarded or regenerated through a separate reprocessing process.

Therefore, it is very necessary to effectively decompose a process gas such as a fluorine compound and effectively remove CO ₂ generated in the decomposition process from the exhaust gas.

Accordingly, a first object of the present invention is to provide a process gas treatment method capable of effectively decomposing a process gas and effectively reducing CO ₂ generated in the decomposition process from exhaust gas.

A second problem to be solved by the present invention is a process gas processing apparatus capable of simultaneously performing a process gas process and a CO ₂ process.

In order to solve the first problem, the present invention provides a method of manufacturing a plasma processing apparatus, comprising: plasma-decomposing a process gas to form an exhaust gas containing carbon dioxide; And adsorbing carbon dioxide in the exhaust gas using a substance activated by the plasma. The process gas may include a fluorine compound, and the plasma decomposition may proceed under an atmosphere of oxygen and H ₂ O. The material may also be a catalyst or a device.

The plasma decomposition is also performed by applying a power between 0.5 kW and 10 kW using a microwave plasma with a wavelength of 50 Hz to 3 GHz, and the catalyst contains magnesium and silicon at the same time. In one embodiment of the present invention, the catalyst is Mg ₃ Si ₄ O ₁₀ (OH) ₂ .

In order to solve the above-mentioned second problem, the present invention provides a plasma processing apparatus comprising: a reactor for plasma-decomposing a process gas to form an exhaust gas containing carbon dioxide; A discharge line through which the exhaust gas decomposed in the reactor is discharged; And a CO ₂ adsorbing material disposed between the discharge line and the reactor and activated by a plasma discharged from the reactor. Wherein the process gas comprises a fluorine compound and the plasma decomposition may be performed in an oxygen and H ₂ O atmosphere.

The plasma decomposition is performed by applying a power between 0.5 kW and 10 kW using a microwave plasma having a wavelength of 50 Hz to 3 GHz, and the catalyst may contain magnesium and silicon at the same time. In one embodiment of the present invention, the catalyst is Mg ₃ Si ₄ O ₁₀ (OH) ₂ . Further, the reactor, the discharge line, and the catalyst may be integrally provided in one chamber, and the entire process gas processing system may be equipped with the process gas processing apparatus.

The process gas processing method according to the present invention reduces the amount of CO _{2 in} the exhaust gas to a considerable level by effectively adsorbing CO ₂ generated at the same time as decomposing the fluorine-containing process gas generated after the semiconductor process by the plasma It is not only economical but also environmentally friendly. Furthermore, the catalyst used can be reused for other purposes without a separate regeneration process.

Hereinafter, the present invention will be described in detail with reference to the drawings, examples, and the like. It is to be understood, however, that the scope of the present invention is not limited to the following embodiments.

One embodiment of the process gas treating method according to the present invention is a fluorine compound, for example a fluorine compound such as C ₂ F ₆ , CF ₄ , CHF ₃ , SF ₆ , NF ₃ , preferably C _x F _y (x, and y is an integer) to a plasma. However, the present invention is not limited to the gas containing the fluorine compound itself, and can be applied to any process gas (carbon containing gas) which can be decomposed by plasma such as VOCs to generate carbon dioxide, all belonging to the scope of the present invention . However, the present invention will be described in more detail below with a process gas containing a fluorine compound to facilitate a better understanding of the present invention.

The process gas containing a fluorine compound or the like is unreacted in the semiconductor process such as an etching process or occurs as a by-product of the reaction. Therefore, the term "process gas" in the term of the process gas treatment method according to the present invention means a gas generated from a semiconductor process or the like.

Since the plasma process is a radical reaction, the reaction rate is very fast. In the microwave plasma, the maximum temperature at the center is about 6000 degrees, which is the temperature at which most compounds are decomposed. Accordingly, the fluorine compound generated in the semiconductor process is decomposed into various radical species according to the plasma reaction. If oxygen is used, carbon in the fluorine compound is decomposed into carbon dioxide or carbon monoxide. Among these, carbon monoxide is converted to stable carbon dioxide (CO ₂ ) under the heated temperature condition, so that all the gas generated from the carbon becomes carbon dioxide.

In one embodiment of the present invention, H ₂ O is contained in the plasma gas component in order to remove the fluorine-containing compound generated by the plasma decomposition. The H ₂ O replaces the fluorine compound activated by the plasma with HF, which is the simplest form. Since the HF is condensed as the temperature decreases after the reaction, it can be easily removed from the exhaust gas.

In an embodiment of the present invention, the plasma process is performed in a microwave manner, but any type of plasma including RF, DC, and MF including microwaves can be used, and this is within the scope of the present invention.

According to the plasma decomposition conditions based on the above embodiment of the present invention, the plasma decomposition is performed by applying power between 0.5 kW and 10 kW at a wavelength range of 50 Hz to 3 GHz. If the plasma process condition is lower than the wavelength and the power range, it is difficult to achieve a sufficient decomposition effect. If the plasma process condition is higher than the process condition, a higher power consumption is used, which is not economically effective.

Furthermore, the process gas processing method according to the present invention uses a material that is activated by the plasma and can effectively adsorb and remove CO ₂ , and the surface of the apparatus such as a catalyst or a pipe can be used as the material.

Particularly, in an embodiment of the present invention, it has been found that, when a catalyst having a high content of silicon and magnesium, particularly silicon oxide and magnesium oxide, is used, the catalyst can be activated by the plasma to effectively reduce CO ₂ . That is, the catalyst used in one embodiment of the present invention is activated at a temperature between 700 and 1100 degrees to adsorb and collect CO _{2. In the} present invention, the plasma temperature discharged from the plasma reactor corresponds to the temperature In the present invention, since the temperature at which the fluorine compound decomposes using microwave plasma is more than 1000 ° C., it has the remarkable effect that the catalyst can be activated and CO ₂ can be reduced without consuming the heat source.

The present invention further CO ₂ by the plasma CO ₂ is more effectively adsorbed to the catalyst and can be removed from the exhaust gas as compared with the prior art in which CO ₂ in a low temperature state is reduced because it is activated.

The catalyst is described in more detail below. In one embodiment of the present invention, as described above, a catalyst containing magnesium and silicon oxide is provided as the catalyst capable of being effectively activated by plasma and effectively removing CO ₂ . In particular, magnesium in the catalyst is the MgCO ₃ in combination with CO ₂ are formed is MgCO _3, known as the limestone is separated it can be reused in another application. Therefore, in the present invention, an unnecessary process of reprocessing the catalyst on which CO ₂ is adsorbed to reproduce the catalyst can be avoided, and in particular, the catalyst used in one embodiment of the present invention is significantly superior to the catalyst used in the above- One aspect of the present invention that the reaction product can be used for another purpose in that it is inexpensive is obviously advantageous over the prior art.

In one embodiment of the present invention with CO ₂ adsorption catalyst _{Mg 3 Si 4 O 10 (OH} ) were used. _2, the catalyst for adsorbing the CO ₂ in accordance with the formula (I), the powders reused for other purposes (MgCO ₃ , SiO ₂ ) is formed.

In order to demonstrate the excellent effects of the process according to the present invention, comparative experiments were carried out for the case where the catalyst activated by the plasma according to the present invention was installed at the rear end of the reactor (Example) And the results of the above comparative experiment are shown in FIG.

FIG. 1 is a graph showing an absorption peak for an exhaust gas passing through a catalyst, wherein the peak height represents the CO ₂ content in the exhaust gas. The higher the peak of 2300 to 2400 cm ^-1 region in the graph, the higher the CO ₂ content in the exhaust gas, and the lower the peak, the lower the CO ₂ content in the exhaust gas.

Referring to Figure _{1, Mg 3 Si 4 O 10} (OH) if the plasma decomposition of CF ₄ by using ₂ as a catalyst _{(Example) Mg 3 Si 4 O 10 (} OH) plasma decomposition without using ₂ as a catalyst , The CO ₂ content of the exhaust gas is considerably reduced as compared with the case (Comparative Example).

From the above results, it can be seen that, when Mg ₃ Si ₄ O ₁₀ (OH) ₂ is used as a catalyst and activated by plasma, the CO ₂ content in the exhaust gas can be effectively reduced. Further, If the residence time is increased, the CO ₂ content in the exhaust gas can be further reduced.

According to another aspect of the present invention, there is provided a plasma processing apparatus comprising: a reactor for plasma-decomposing a process gas containing a fluorine compound to form an exhaust gas containing carbon dioxide; A discharge line through which the exhaust gas decomposed in the reactor is discharged; And a CO ₂ adsorption catalyst provided between the discharge line and the reactor and activated by a plasma discharged from the reactor.

Hereinafter, a process gas processing apparatus according to the present invention will be described in detail with reference to the drawings.

2 is a schematic diagram of a process gas processing apparatus according to an embodiment of the present invention.

Referring to FIG. 2, a reactor 200 in which a process gas generated in a semiconductor process or the like is introduced to perform plasma decomposition is disclosed. Also, the process gas processing apparatus according to the present invention includes a discharge line 220 connected to the reactor 200 to discharge the decomposed reaction gas, and further includes a discharge line 220 between the reactor 200 and the discharge line 220 A material 210 for adsorbing CO ₂ is provided. Since the material 210 is activated by the plasma and effectively removes CO ₂ as described above, the reaction gas discharged from the reactor 200 is first contacted with the material, and then is discharged to the outside through the discharge line 220 .

If the catalyst is a catalyst, the catalyst may be deposited in the piping of the exhaust line 220, or if necessary, the catalyst 210 may be exhausted from the reactor 200 to the catalyst For example, a structure such as a baffle may be provided to increase the residence time of the exhaust gas in the catalyst 210. [0050] Instead of using a separate powder type catalyst, CO ₂ removal by the device itself may be achieved by laminating a separate coating layer on the surface of the device.

Further, in the present invention, the plasma generated in the reactor is partially discharged from the reactor to activate the catalyst provided outside the reactor.

3 is a schematic diagram showing a reactor of a process gas processing apparatus according to an embodiment of the present invention.

Referring to FIG. 3, the reactor decomposes the process gas using a microwave plasma. Particularly, in the present invention, a part of the plasma flame is discharged from the reactor, and the temperature of the discharge plasma is higher than about 1000 degrees. In the embodiment of the present invention, the discharge of the plasma flame is performed through a connection port to which a pipe of the discharge line 220 is connected, and the catalyst deposited in the discharge line 220 adjacent to the reactor is discharged to the discharged plasma flame . Thus, the catalyst outside the reactor in contact with the discharge plasma reaches a temperature condition at which the catalyst can be activated.

In one embodiment of the present invention, the plasma decomposition is performed by applying a power between 0.5 kW and 10 kW using a microwave plasma having a wavelength of 50 Hz to 3 GHz, and the catalyst may contain magnesium and silicon at the same time. Therefore, the catalyst containing both magnesium and silicon is activated by the plasma as described above, adsorbing CO ₂ , and forming a reusable powder such as limestone.

In addition, since the above-described process gas processing apparatus of the present invention does not include a large-scale component such as a scrubber, each component can be provided in one chamber. In this case, plasma generation, process gas decomposition, and carbon dioxide removal can all be performed in one chamber as a whole, and therefore, it is very economical compared to the prior art in which a separate scrubber or the like is required to remove carbon dioxide.

1 is a graph showing an absorption peak for an exhaust gas passing through a catalyst.

2 is a schematic diagram of a process gas processing apparatus according to an embodiment of the present invention.

3 is a schematic diagram showing a reactor of a process gas processing apparatus according to an embodiment of the present invention.

Claims (12)

Plasma decomposing the process gas to form an exhaust gas containing carbon dioxide; And And adsorbing carbon dioxide in the exhaust gas using a substance activated by the plasma. The method according to claim 1, Wherein the material is a catalyst or a device. The method according to claim 1, Wherein the process gas contains a fluorine compound and the plasma decomposition is conducted under an atmosphere of oxygen and H ₂ O. The method according to claim 1, Wherein the plasma decomposition is performed by applying a power between 0.5 kW and 10 kW using a microwave plasma with a wavelength of 50 Hz to 3 GHz. The method according to claim 1, Wherein said catalyst simultaneously contains magnesium and silicon. 6. The method of claim 5, Wherein the catalyst is Mg ₃ Si ₄ O ₁₀ (OH) ₂ . A reactor for plasma-decomposing the process gas to form an exhaust gas containing carbon dioxide; A discharge line through which the exhaust gas decomposed in the reactor is discharged; And a CO ₂ adsorbing material disposed between the discharge line and the reactor and activated by plasma discharged from the reactor. 8. The method of claim 7, Wherein the process gas contains a fluorine compound and the plasma decomposition is carried out in an atmosphere of oxygen and H2O. 8. The method of claim 7, Wherein the plasma decomposition is performed by applying a power between 0.5 kW and 10 kW using a microwave plasma of a wavelength of 50 Hz to 3 GHz. 8. The method of claim 7, Wherein the material is a catalyst containing both magnesium and silicon at the same time. 11. The method of claim 10, Wherein the catalyst is Mg ₃ Si ₄ O ₁₀ (OH) ₂ . 8. The method of claim 7, Wherein the reactor, the discharge line and the material are integrally provided in one chamber.

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