JP2003305334A - Plasma type pfc decomposition system and pfc decomposition method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma type PFC (perfluorocompound) decomposition system having a means for maintaining high PFC decomposition performance by efficiently removing metal impurities contained in PFC-containing gas and preventing the clogging caused by the deposition of the metal impurities, the corrosion of exhaust gas suction devices caused by corrosive gas, and the like. <P>SOLUTION: In the plasma type PFC decomposition system where PFC- containing exhaust gas discharged from a plasma device 1 by a first exhaust gas suction device 2 is introduced into a plasma type PFC decomposition device 4 to be decomposed and the decomposed gas is discharged by a second exhaust gas suction device 5, metal impurity removing equipment 3 is installed between the first exhaust gas suction device 2 and the plasma type PFC decomposition device 4. The fixing of the metal impurities to the plasma type PFC decomposition device 4 or piping, the corrosion of the exhaust gas suction devices caused by corrosive gas, and the like, can be inhibited. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plasma type PFC.
Decomposition system and PFC decomposition method, especially PFC
Efficiently removes metallic impurities contained in the contained gas,
The present invention relates to means for suppressing performance degradation of an FC decomposition device.

[0002]

2. Description of the Related Art PFC (perfluoro compound) is
It is a general term for fluorine compounds such as CF ₄ , C ₂ F ₆ , and SF ₆ , and is a global warming substance. Therefore, the establishment of measures to control atmospheric emission is an urgent task.

PFC is used as an etching gas or a cleaning gas in a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus, and a processing technique is applied to a released gas such as an unused PFC or a low-molecular PFC generated by etching.
It is being considered on a global scale.

PFC became a regulated gas at the 1997 International Conference on Global Warming Prevention (COP3).
At the 3rd World Conference on Semiconductors in 1999, reduction targets were set.

One of various measures to suppress atmospheric release is a decomposition / fixation technique. As the decomposition technique, there are a combustion method, a plasma method, a catalyst method and the like. The plasma method is a promising processing technology because the apparatus is compact and can be incorporated in an existing line of a semiconductor etching apparatus, for example.

Japanese Unexamined Patent Publication No. 2000-317265 shows a thermal decomposition type plasma device.

[0007]

However, the exhaust gas containing PFC often contains precipitable metal impurities, and these metal impurities are plasma due to reaction with moisture or temperature change. It has been found that it precipitates in the PFC decomposer and piping and causes problems such as clogging.

Further, the corrosive gas generated from the metal impurities corrodes the exhaust gas suction device and the like.

Therefore, in actual operation, high PFC
In order to maintain decomposing performance, prevent clogging caused by the precipitation of metal impurities and corrosion of the exhaust gas suction device caused by corrosive gas, and reduce maintenance labor and cost, these impurities are automatically added as much as possible. Need to be removed.

An object of the present invention is to efficiently remove metal impurities contained in a PFC-containing gas, prevent clogging caused by precipitation of metal impurities, and prevent corrosion of an exhaust gas suction device caused by corrosive gas. Plasma-based PFC decomposition system equipped with means for maintaining PFC decomposition performance and P
It is to provide an FC decomposition method.

[0011]

In order to achieve the above object, the present invention introduces an exhaust gas containing PFC (perfluoro compound) discharged from a plasma device by a first exhaust gas discharge device into a plasma PFC decomposition device. In the plasma type PFC decomposition system that decomposes and decomposes and exhausts the decomposed gas by the second exhaust gas discharging means, a plasma type PFC decomposition system having metal impurity removal equipment between the first exhaust gas discharging means and the plasma decomposition device is proposed. To do.

In the exhaust gas discharged from the plasma device such as an etcher by the first exhaust gas discharging means, in addition to PFC, solid metal impurities, a reaction in the gaseous state with water and a decrease in temperature produce solids. May contain metallic impurities. When metal impurities are contained, if they are removed before the decomposition device, the decomposition device can be operated for a long time without degrading the PFC decomposition performance.

In the present invention, the exhaust gas containing PFC (perfluoro compound) discharged from the plasma device by the first exhaust gas discharging means is introduced into the plasma type PFC decomposer to decompose it, and the decomposed gas is discharged into the second exhaust gas. In the plasma type PFC decomposition system exhausting by means, a metal impurity removing equipment comprising a cyclone for removing coarse particles of metal impurities and a filter for removing fine particles of metal impurities after that is provided between the first exhaust gas discharging means and the plasma decomposition apparatus. We propose a plasma-type PFC decomposition system equipped in between.

The solid metal impurities are coarsely removed by a cyclone, and the remaining fine powder metal impurities are removed by a filter.
If there is a limit to the particle size that can be removed using only a cyclone, fine powder that cannot be removed is removed by a filter.

The present invention further comprises a first plasma device.
In a plasma type PFC decomposition system in which exhaust gas containing PFC (perfluoro compound) discharged by the exhaust gas discharging means is introduced into a plasma type PFC decomposition device and decomposed, and decomposed gas is discharged by the second exhaust gas discharging means,
Between the first exhaust gas discharge means and the plasma decomposition device, there is provided a metal impurity removing device comprising a means for coarsely powdering metal impurities, a cyclone for removing coarse powders of metal impurities, and a filter for removing fine powders of metal impurities thereafter. We propose a plasma type PFC decomposition system equipped with it.

Here, the coarse powder is defined as a powder having a particle size of 10 μm or more, and the fine powder is defined as a powder having a particle size of less than 10 μm. According to the third aspect of the present invention, the fine metal impurities are coarsely powdered in the preceding stage of the cyclone to enhance the removal efficiency in the cyclone. As a result, the maintenance labor of the fine powder removing filter installed in the latter stage of the cyclone is reduced.

The means for roughening the metal impurities may be means for bringing the metal impurities in the exhaust gas into contact with the aggregating agent to roughen the particles.

As a method of coarsening, a flocculant is used,
Fine powder metal impurities are coarsely powdered to enhance the cyclone removal efficiency. Further, the metal powder is adsorbed on the coagulant itself, and the metal powder adsorbing coagulant is removed by a cyclone.

The means for roughening the metal impurities may be means for changing the temperature of the exhaust gas to a temperature below the freezing point of the metal impurities to change it from a gas or a liquid to a solid and roughen it.

When the temperature of the gas exhausted by the first exhaust gas discharge means is adjusted to a temperature below the freezing point of the metal impurities to solidify and remove the gas metal impurities, the metal impurities flow into the plasma type PFC decomposer in a gaseous state. Can be suppressed.

In any of the above plasma-type PFC decomposition systems, the metal impurity removing equipment makes countercurrent contact between the gas discharged from the first exhaust gas discharge means and a warm alkaline aqueous solution for removing metal impurities from the gas. It is also possible to have a flue gas cleaning tower.

The gas exhausted by the first exhaust gas discharge means is brought into contact with an alkaline aqueous solution heated to about 50 to 80 ° C. to dissolve or polymerize the metal impurities and remove the metal impurities from the exhaust gas.

More specifically, the exhaust gas is an exhaust gas of a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus.

In the present invention, the P discharged from the plasma device is
In a plasma PFC decomposition method in which exhaust gas containing FC (perfluoro compound) is introduced into a plasma PFC decomposition apparatus and decomposed, and the decomposition gas is exhausted, a plasma PFC that removes metal impurities removal upstream of the plasma decomposition apparatus Propose a disassembly method.

According to the present invention, the P discharged from the plasma device is
In a plasma PFC decomposition method in which exhaust gas containing FC (perfluoro compound) is introduced into a plasma PFC decomposition apparatus and decomposed, and decomposed gas is exhausted, coarse powder of metal impurities is removed upstream of the plasma decomposition apparatus, After that, a plasma PFC decomposition method for removing fine particles of metal impurities is proposed.

The present invention further provides a plasma PFC decomposition method in which exhaust gas containing PFC (perfluoro compound) discharged from the plasma device is introduced into a plasma PFC decomposition device for decomposition, and the decomposition gas is exhausted. We propose a plasma-type PFC decomposition method in which metal impurities are coarsely powdered upstream of the decomposing device, coarse powder of metal impurities is removed, and then fine powder of metal impurities is removed.

The first exhaust gas discharging means and the plasma type P
A metal impurity removing facility may be provided between the FC decomposition device and between the plasma PFC decomposition device and the second exhaust gas discharging means.

If a metal impurity removing device is also provided in the latter stage of the plasma type PFC decomposing device, it is possible to remove metal impurities that cannot be completely removed in the former stage of the plasma type PFC decomposing device and metal compounds produced in the PFC decomposing device. Does not deteriorate the performance of the exhaust gas discharge means.

Exhaust gas from plasma devices for cleaning and etching in the semiconductor manufacturing process and liquid crystal manufacturing process often contains WF ₆ , TaF ₅ , BCl _{3 and the} like as metal impurities.

These may be solidified due to a decrease in exhaust gas temperature or a reaction with water, and may be deposited in the plasma apparatus and in the pipes in the latter stage of the plasma apparatus to cause blockage.

Therefore, it is necessary to efficiently remove metal impurities before the plasma type PFC decomposer.

Specifically, since the exhaust gas contains solid or gaseous metal impurities, the solid ones are removed by a mechanical separation operation such as a cyclone. Fine powder that cannot be removed by the cyclone is removed by a filter.

Since the exhaust gas contains an acidic gas such as HF, a corrosion resistant material (Teflon (registered trademark), vinyl chloride, etc.) is used.

The filter is regularly cleaned.

When these mechanical separation operations are used, no new impurities are generated in the exhaust gas, so that it is possible to suppress the performance deterioration of the plasma PFC decomposition apparatus in the subsequent stage.

On the other hand, it is also possible to coarsely remove the fine powder. A target coagulant of metallic impurities such as Fe, Cr, and W is added to the exhaust gas to coarsen it.

Metal impurities may be adsorbed on the surface of activated carbon, plastic beads or the like and removed by the centrifugal force of a cyclone.

As a method of selecting the coagulant, Pearson H
The SAB law can also be used. For example, Fe ³⁺ ,
A hard acid such as Cr ³⁺ easily reacts with a hard base, and a reagent that can be used in the treatment step can enlarge the molecule by selective masking or the like.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a plasma PFC decomposition system according to the present invention will be described with reference to FIGS.

FIG. 1 is a diagram showing a system configuration of an embodiment of a plasma type PFC decomposition system according to the present invention.

The plasma type PFC decomposition system according to the first embodiment includes the first exhaust gas discharging means (first
The exhaust gas containing PFC (perfluoro compound) discharged by the exhaust gas suction device 2 is introduced into the plasma type PFC decomposition device 4 and decomposed, and the decomposed gas is exhausted by the second exhaust gas discharge means (second exhaust gas suction device) 5. Plasma type P
In the FC decomposition system, the first exhaust gas discharge means (first
A metal impurity removing facility 3 is provided between the exhaust gas suction device 2) and the plasma decomposition device 4.

Exhaust gas from the plasma device 1 used for manufacturing semiconductors and liquid crystals is exhausted by the first exhaust gas discharge means (first exhaust gas suction device) 2, and this exhaust gas is introduced into the metal impurity removing equipment 3.

The gas from which metal impurities have been removed is treated with plasma P
It is introduced into the FC decomposition device 4 and decomposes PFC. The gas after PFC decomposition is exhausted by the second exhaust gas discharge means (second exhaust gas suction device) 5.

Plasma devices used for semiconductors and liquid crystals include CVD cleaning and etching. In these plasma devices, PFC is often used.

The first exhaust gas suction device 2 and the second exhaust gas suction device 5 are vacuum pumps, dry pumps, and the like, and may be devices having higher corrosion resistance.

The basic structure of the plasma type PFC decomposer is as follows:
A plasma chamber made of a dielectric material such as quartz, a conductive coil wound around the outer periphery of the chamber, and a high frequency power source connected to both ends of the coil.

Further, in order to increase the PFC decomposition rate, it is desirable to have equipment for introducing water vapor, oxygen, air and the like.

[0048]

[Embodiment 1] FIG. 2 is a diagram showing a configuration of Embodiment 1 in which a cyclone 10 and a filter 13 are used as a metal impurity removing facility according to the present invention.

The gas from the first exhaust gas suction device 2 is introduced into the cyclone 10 to remove coarse particles of about 10 μm or more.
The removed coarse powder is stored in the solid material storage tank 11 from the solid material discharge port below the cyclone 10.

The gas from which the coarse powder has been removed removes fine powder with the filter 13 and is introduced into the plasma type PFC decomposer. The flow passage switching valve 12 is provided before and after the filter 13, and the flow passage is changed at the time of maintenance of the filter.

The cyclone 10 is preferably made of Teflon or PVC corrosion-resistant material. In the cyclone 10, the size and the particle size of the removable powder are determined by the inlet gas velocity and pressure.

The cyclone 10 may be optimally designed according to the semiconductor manufacturing line or liquid crystal manufacturing line to which the present invention is applied. Usually, the 50% separation diameter is 1 to 50 μm,
The pressure loss is about 50 to 500 mmH ₂ O.

The filter 13 is determined by the particle size of the separated particles in the cyclone 10 in the preceding stage. It is desirable that the material of the filter 13 is also corrosion resistant.

It is desirable that the flow path switching valve 12 has a shape that branches into a Y-shape so that metal impurities are hard to be deposited and the flow path can be changed.

It is desirable that all the gas flow paths shown in FIG. 2 be corrosion resistant.

The cyclone 10 is a device for removing small solid particles and liquid droplets in the air stream by centrifugal force. When the gas containing the powder is introduced into the cyclone 10 at high speed, the powder hits the inner wall of the cylinder toward the outside by the centrifugal force. The powder that hits the inner wall is extracted from the bottom,
The gas from which the powder has been removed rises and escapes from the upper part.

The size of the cyclone 10 depends on the particle size of the powder to be removed. If the inner diameter of the cyclone is small and the gas inlet velocity is high, the centrifugal force is large and small mist can be removed. For example, in order to collect mist of about 1 μm, the radius may be 1 cm and the inlet gas velocity may be about 20 m / sec.

The inlet gas flow velocity of the cyclone 10 is 10 to
It is preferably used at 30 m / sec. Below this flow rate, the removal efficiency decreases. On the other hand, the higher the entrance speed,
The removal rate increases, but the pressure loss increases.

The filter 13 is a device for removing a powder by passing a gas flow containing mist through fine pores. When the gas velocity in the filter is 5 to 25 cm / sec,
To remove 1 μm powder, use a filter with a pore size of 250 μm or less. In particular, a filter of 160 μm or less is preferable.

Also in the filter 13, the cyclone 10
Similar to the case, if the pore size is large, the removal rate of the powder is reduced, and if it is small, the removal rate is high, but the pressure loss increases.

The material of the filter 13 may be a commercially available glass material. However, when there is an acidic gas such as HF, it is preferably made of ceramics or the like.

It is also possible to remove it by wet electrostatic collection. The electrostatic precipitator is a device in which a gas is caused to flow in a strong electric field to be charged, and powder is collected at the opposite electrode portion. In this case, it is desirable to apply a voltage of 8 kV or more. It is also preferable to flow air or the like so that the mist does not adhere to the electrode portion. When the mist adheres to the electrodes, it short-circuits and the voltage does not rise. For the electrode of the electrostatic precipitator, tungsten wire, S
US wire etc. can be used.

In any of the above methods for removing metal impurities, the flow rate of the processing gas is important. When the amount of gas introduced into the PFC removal device decreases, it is desirable to add an inleak gas to match the gas flow rate with the set flow rate used when designing the powder removal device.

60 liters / minute of a tungsten silicide etcher exhaust gas diluted with nitrogen for vacuum pump purging was introduced into a cyclone having an inner diameter of 24 mm and a height of 111 mm under the condition of an inlet speed of about 20 m / sec. The cyclone outlet gas was exhausted through a filter having a pore size of 160 μm or less.

The gas moves while rotating from the upper part to the lower part in the cyclone, the solid particles are removed by the centrifugal force, and the gas is discharged from the gas discharge port in the upper part of the cyclone. As a result of analyzing W after passing through the filter, it was 1 mg / m ³ or less.

The WO ₃ particles removed by the cyclone are discharged from the powder discharge port (inner diameter 24 mm) at the bottom of the cyclone.

[0067]

[Embodiment 2] FIG. 3 is a diagram showing the structure of Embodiment 2 in which a mixer 15 for mixing the coagulant 14 with the exhaust gas from the first exhaust gas suction device 2 is installed according to the present invention.

The mixer 15 has an exhaust gas inlet, a coagulant inlet, and a mixer exhaust gas outlet. The exhaust gas from the first exhaust gas suction device 2 is introduced so as to generate a swirling flow in the mixer 15. On the other hand, the coagulant 14 is introduced from the coagulant inlet provided outside the exhaust gas inlet.

The exhaust gas velocity is adjusted to be higher than the coagulant introduction velocity so that the metal impurities in the exhaust gas come into contact with the coagulant 14 while advancing toward the inner wall of the mixer 15.

It is desirable to control the residence time of the flocculant 14 in the mixer 15. For example, adjust the swirl angle,
It is desirable to secure a sufficient time so that when the metal impurities adhere to the coagulant 14 and the weight changes, the coagulant 14 is discharged from the mixer 15.

To this end, the residence time holding gas stream may be introduced below the mixer 15 and further outside the inlet of the flocculant 14.

The coagulant 14 to be charged is preferably inexpensive and easy to process, such as activated carbon or plastic beads.

[0073]

[Third Embodiment] FIG. 4 is a diagram showing the structure of a third embodiment in which the temperature of exhaust gas is adjusted to remove metallic impurities in a gas according to the present invention.

The heat exchanger 16 is installed between the first exhaust gas suction device 2 and the cyclone 10. The heat exchanger 16 causes the cooling liquid to flow to the outside in a countercurrent flow with the exhaust gas to reduce the exhaust gas temperature. Usually, most metal impurities are solid at room temperature, and can be removed as solids by lowering the exhaust gas temperature to about 5 to 10 ° C.

At the position of the exhaust gas introduction port to the heat exchanger 16, in order to prevent clogging, the gas temperature is not lowered so that metal impurities are not deposited. Further, when the exhaust gas is introduced so as to cause a swirling flow in the heat exchanger 16, the removal efficiency is increased.

CF ₄ concentration 0.5%, Ta concentration 550 mg
/ M ³ (input as TaF ₅ ), N ₂ balanced reaction gas at a flow rate of 30 liters / min.
Was supplied to the heat exchanger 16. As a cooling liquid, a temperature of 10
The water at ℃ was flown outside the heat exchanger 16. The heat exchanger had an inner diameter of 150 mm and a length of 1,500 mm, and a pipe having an inner diameter of 8 mm was spirally wound around the outer side of the heat exchanger, and cooling water of 10 ° C. was flowed.

The reaction gas causes a swirling flow in the heat exchanger 16 and is discharged from the outlet of the heat exchanger. Residence time is 2.6
Minutes. Ta concentration at the heat exchanger outlet is 1 mg / m ³
It was below, and the removal rate was 99.8%.

[0078]

[Fourth Embodiment] FIG. 5 shows a fourth embodiment for removing gaseous and solid metal impurities by using a warm alkaline solution according to the present invention.
It is a figure which shows the structure of.

The exhaust gas cleaning tower 17 has an inlet for introducing the exhaust gas from the first exhaust gas suction device 2, an inlet for the warm alkaline liquid 18, and a spray nozzle for the warm alkaline liquid 19. The exhaust gas after coming into contact with the warm alkaline liquid is discharged from the upper stage of the exhaust gas cleaning tower 17, and the warm alkaline liquid is discharged from the lower portion of the exhaust gas cleaning tower 17.

As the cleaning tower of the exhaust gas cleaning tower 17, a normal packed tower, a spray tower or the like can be used. It is desirable to combine a packed tower and a spray tower.

Exhaust gas always comes into contact with the warm alkali liquid in the packed tower portion of the exhaust gas washing tower 17, and even in the subsequent stage, it comes into contact with the warm alkali liquid sprayed from the spray tower.

The temperature of the warm alkaline liquid may be adjusted in advance and introduced into the exhaust gas cleaning tower 17, but the exhaust gas cleaning tower 17 may be heated from the outside. Also, it may be thermally insulated.

A reaction gas having a flow rate of WF _{6 of} 40 ml / min and an air flow rate of 120 liter / min was introduced into an exhaust gas washing tower having an inner diameter of 150 mm and a length of 1000 mm.

A full cone type spray nozzle is installed above the exhaust gas cleaning tower 17, and the temperature is about 60 ° C. at 1 liter / min.
1 mol / liter sodium hydroxide aqueous solution was sprayed. The reaction gas enters from the lower stage of the exhaust gas cleaning tower 17 and is discharged from the upper stage outlet.

[0085] For inlet W concentration 8114mg / ^{m 3,} the outlet concentration of W became 1 mg / ^{m 3.}

[0086]

Fifth Embodiment In the first to fourth embodiments, the configuration of cyclone device 10 + filter 13, cyclone device 10 + coagulant mixer 15, cyclone device 10 + heat exchanger (exhaust gas cooler) 16, cyclone device 10 + exhaust gas cleaning tower 17 The cyclone device 10, the filter 13,
Any one of the coagulant mixer 15, the heat exchanger (exhaust gas cooler) 16 and the exhaust gas cleaning tower 17 may be adopted independently.

In addition to the above combinations, cyclone device 10, filter 13, coagulant mixer 15, heat exchanger
(Exhaust gas cooler) 16 and at least 2 of exhaust gas cleaning tower 17
You can also combine the two.

Furthermore, in addition to between the first exhaust gas suction device 2 and the plasma decomposition device 4, the plasma decomposition device 4 and the second decomposition device
A metal impurity removing facility may be additionally arranged between the exhaust gas suction device 5.

As described above, the plasma type PFC decomposition apparatus 4
If a metal impurity removing device is provided in the subsequent stage, plasma type P
It is possible to remove metal impurities that cannot be completely removed upstream of the FC decomposition device 4 and metal compounds that are generated in the PFC decomposition device 4, and it is possible to prevent performance degradation of the second exhaust gas suction device 5.

[0090]

According to the present invention, the first plasma device
Plasma type PFC in which the exhaust gas containing PFC discharged by the exhaust gas discharge means is introduced into a plasma type PFC decomposition apparatus to decompose and the decomposed gas is discharged by the second exhaust gas discharge means.
In the decomposition system, since the metal impurity removal equipment is provided between the first exhaust gas discharge means and the plasma PFC decomposition device, the metal exhaust gas is adhered to the plasma PFC decomposition device or the pipe or the exhaust gas suction device is corroded due to corrosive gas. Can be suppressed.

Further, the metal impurities contained in the PFC-containing gas can be removed efficiently, and the performance deterioration of the PFC decomposition apparatus can be suppressed.

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration of an embodiment of a plasma PFC decomposition system according to the present invention.

FIG. 2 is a diagram showing a configuration of a first embodiment in which a cyclone 10 and a filter 13 are used as a metal impurity removing facility according to the present invention.

FIG. 3 is a diagram showing a configuration of a second embodiment in which a mixer 15 for mixing the coagulant 14 with the exhaust gas from the first exhaust gas suction device 2 is installed according to the present invention.

FIG. 4 is a diagram showing a configuration of a third embodiment for adjusting exhaust gas temperature and removing metallic impurities in a gas according to the present invention.

FIG. 5 is a diagram showing a configuration of a fourth embodiment in which a warm alkaline liquid is used to remove gas and solid metal impurities according to the present invention.

[Explanation of symbols] 1 Plasma device 2 First exhaust gas discharge means (first exhaust gas suction device) 3 Metal impurities removal equipment 4 Plasma type PFC decomposer 5 Second exhaust gas discharge means (second exhaust gas suction device) 10 Cyclone device 11 Solids storage tank 12 flow path switching valve 13 filters 15 Flocculant mixer 16 heat exchanger (exhaust gas cooler) 17 Exhaust gas cleaning tower 18 warm alkaline liquid 19 Warm alkaline liquid spray nozzle 20 cleaning liquid

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01D 53/64 B07B 7/08 4H006 B01J 19/08 C07B 35/06 B07B 7/08 37/06 C07B 35 / 06 C07C 19/08 37/06 B01D 53/34 134C C07C 19/08 136Z (72) Inventor Hideaki Kurokawa 4, 6 Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. (72) Inventor Shinichi Ichikawa Hitachi, Ibaraki Prefecture 2-1 Mika-cho, Omika-cho, Hitachi, Ltd. Power & Electric Development Laboratory (72) Inventor Toshio Yamashita 7-2-1, Omika-cho, Hitachi, Ibaraki Hitachi, Ltd. (72) Inventor Teruaki Kawasaki 7-2 Omika-cho, Hitachi City, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. F-term in the research institute (reference) 4D002 AA01 AA17 AA18 AA22 AA28 AC10 BA02 BA04 BA07 BA13 BA14 CA01 CA13 DA01 DA12 DA41 DA70 EA02 HA01 HA06 4D021 FA25 GA06 GB02 HA10 4D032 AC07 BB01 4A0 A01 BA01 A03 A01 A01 A15 A03 A11A03 A11 A03 CA25 DA01 EB01 EB41 FB06 FC15 4H006 AA05 AC13 AC26 BA91 BA95 BD10 BD60 EA02

Claims (10)

[Claims] 1. An exhaust gas containing PFC (perfluoro compound) discharged from a plasma device by a first exhaust gas discharge means is introduced into a plasma type PFC decomposition apparatus and decomposed, and a decomposed gas is exhausted by a second exhaust gas discharge means. In the plasma PFC decomposition system, a metal impurity removal facility is provided between the first exhaust gas discharging means and the plasma decomposition device. 2. Exhaust gas containing PFC (perfluoro compound) discharged from the plasma device by the first exhaust gas discharging means is introduced into a plasma type PFC decomposer and decomposed, and decomposed gas is exhausted by the second exhaust gas discharging means. In the plasma-type PFC decomposition system, a metal impurity removing device including a cyclone for removing coarse particles of metal impurities and a filter for subsequently removing fine particles of metal impurities is provided between the first exhaust gas discharge means and the plasma decomposition apparatus. Plasma type PFC characterized by having
Disassembly system. 3. Exhaust gas containing PFC (perfluoro compound) discharged from the plasma device by the first exhaust gas discharge means is introduced into a plasma type PFC decomposer and decomposed, and decomposed gas is exhausted by the second exhaust gas discharge means. In the plasma-type PFC decomposition system, the first exhaust gas discharge means is provided with a metal impurity removing facility including a means for coarsely powdering metal impurities, a cyclone for removing coarse powders of metal impurities, and a filter for subsequently removing fine powders of metal impurities. A plasma type PFC decomposition system, which is provided between the plasma decomposition apparatus and the plasma decomposition apparatus. 4. The plasma-type PFC decomposition system according to claim 3, wherein the means for roughening the metal impurities is a means for bringing the metal impurities in the exhaust gas into contact with the aggregating agent to roughen the particles. Characteristic plasma type PFC decomposition system. 5. The plasma type PFC decomposition system according to claim 3, wherein the means for coarsely pulverizing the metal impurities changes the temperature of the exhaust gas to a temperature equal to or lower than the freezing point of the metal impurities to change from a gas or a liquid to a solid to coarsely pulverize. Means for plasma type PF
C decomposition system. 6. The plasma PFC decomposition system according to any one of claims 1 to 5, wherein the metal impurity removal facility includes a gas discharged from the first exhaust gas discharge means and a metal impurity from the gas. A plasma-type PFC decomposition system, comprising an exhaust gas washing tower that makes countercurrent contact with a warm alkaline aqueous solution for removing hydrogen. 7. The plasma PFC decomposition system according to claim 1, wherein the exhaust gas is exhaust gas from a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus. . 8. An exhaust gas containing PFC (perfluoro compound) discharged from a plasma device is converted into plasma P
A plasma-type PFC decomposition method of introducing into an FC decomposition apparatus to decompose and exhausting decomposition gas, wherein removal of metal impurities is removed upstream of the plasma decomposition apparatus. 9. Exhaust gas containing PFC (perfluoro compound) discharged from a plasma device is treated with plasma P
In a plasma-type PFC decomposition method of introducing into an FC decomposition apparatus to decompose and exhausting decomposition gas, it is possible to remove coarse particles of metal impurities upstream of the plasma decomposition apparatus, and then remove fine particles of metal impurities. A characteristic plasma-type PFC decomposition method. 10. PFC discharged from a plasma device
In a plasma PFC decomposition method in which an exhaust gas containing (perfluoro compound) is introduced into a plasma PFC decomposition apparatus and decomposed, and the decomposition gas is exhausted, metal impurities are coarsely powdered upstream of the plasma decomposition apparatus to generate metal impurities. The plasma-type PFC decomposition method, characterized in that the coarse powder of (1) is removed, and then the fine powder of metal impurities is removed.