JPH115012A - Waste gas treatment and treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste gas treating technology by which a waste gas exhausted from a semiconductor manufacturing process or the like is treated to decompose and remove a harmful material and a pollutant contained in the gas. SOLUTION: In a vacuum atmosphere A between plasma electrodes 20, 21, by generating plasma, while a waste gas exhausted from a semiconductor manufacturing process or the like is mixed with a reaction promoting gas, constituents in the waste gas are excited and activated together with the reaction promoting gas to react and on the electrode surface of the plasma electrodes 20, 21, they are deposited and solidified as a plasma reaction product. In this way, a harmful material and a pollutant in the waste gas are decomposed and removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas treatment method and an exhaust gas treatment apparatus, and more particularly, to an exhaust gas treatment technique for treating exhaust gas discharged from various semiconductor manufacturing processes and the like.

[0002]

2. Description of the Related Art Manufacturing equipment using CVD (Chemical Vapor Deposition) such as semiconductor manufacturing, solar cell manufacturing, and LCD manufacturing, etching equipment, ion implantation equipment, PVD (P
hysical Vapor Deposition) In various manufacturing processes (hereinafter, referred to as semiconductor manufacturing processes, etc.) using an apparatus and an apparatus for performing film formation or etching using a reactive gas, various reactive gases are used in large amounts. However, all of these reaction gases are not completely consumed, and unreacted gas and residual gas are discharged together with the reaction product gas.

For example, in a semiconductor manufacturing process by the CVD method, a large amount of silane (SiH ₄ ), titanium tetrachloride (TiCl ₄ ), tungsten hexafluoride (WF ₆ ), ammonia (NH ₃ ), dichlorosilane (SiH ₂ C)
l ₂ ), arsine (AsH ₃ ), phosphine (P
Although a reaction gas such as H ₃ ) or boron tribromide (BBr ₃ ) is used, the amount actually consumed in this manufacturing process is very small.

[0004] As a result, the exhaust gas discharged from this manufacturing process is a large amount and its concentration is relatively high, and some of the exhaust gas include very toxic substances, corrosive substances or flammable substances. Hazardous and polluting substances are contained, and these exhaust gases cannot be released to the atmosphere as it is, not only for environmental sanitation but also for legal purposes. ing.

As this type of exhaust gas treatment method, conventionally,
Wet type that removes harmful and pollutants in exhaust gas with water or chemicals, dry type that reacts or burns exhaust gas at high temperature to decompose and process harmful and pollutants, chemical liquid combustion type that combines both types, or in the exhaust gas by microorganisms There are various methods such as a microbial method for decomposing harmful and polluting substances. Then, various exhaust gas treatment devices utilizing these methods have been developed and proposed, and this device is arranged downstream of the semiconductor manufacturing process and appropriately decomposes and removes exhaust gas discharged from the semiconductor manufacturing process. Was to be released to the atmosphere.

On the other hand, the harmful and polluting substances thus decomposed are collected in a collecting cartridge of the above-mentioned exhaust gas treatment apparatus, and are discarded together with the cartridge.

[0007]

However, in any of these conventional exhaust gas treatment methods, the decomposition and removal of harmful and polluting substances contained in the exhaust gas is not yet complete, and it is not possible to comply with environmental hygiene or legal standards. Although the level is satisfactory, the problem of air pollution still remains, and further improvement in treatment efficiency has been desired.

In the case where the exhaust gas treatment device is interposed between the reaction vessel in the semiconductor manufacturing process and its vacuum pump system, the exhaust gas containing unprocessed substances in the gas treatment device is supplied to the vacuum pump. As a result of pumping into the system, the pump oil reacts with untreated substances in the exhaust gas and deteriorates, which has a problem of shortening the life of the vacuum pump system.

Further, all of the exhaust gas treatment methods are of a type in which the exhaust gas is treated in a lump, and individual components of the mixed gas cannot be removed.

The present invention has been made in view of such conventional problems, and an object of the present invention is to treat exhaust gas discharged from various semiconductor manufacturing processes and the like and include the same in the exhaust gas. An object of the present invention is to provide an exhaust gas treatment technology capable of substantially completely decomposing and removing harmful and polluting substances.

[0011]

In order to achieve the above object, an exhaust gas treatment method of the present invention generates plasma while mixing a reaction promoting gas with exhaust gas discharged from a semiconductor manufacturing process or the like in a vacuum atmosphere. By doing so, the constituent material in the exhaust gas is deposited and solidified as a plasma reaction product. The reaction promoting gas is selected according to the constituents of the exhaust gas to be treated.

As a preferred embodiment, a plasma electrode for generating plasma is arranged in the vacuum atmosphere, the plasma reaction product is deposited and solidified on the surface of the plasma electrode, and the surface of the plasma electrode is treated during exhaust gas treatment. Cooling promotes the solidification of the constituents in the exhaust gas.

Further, an exhaust gas treatment apparatus of the present invention is for carrying out the above-described exhaust gas treatment method, and comprises a closed reaction chamber having an exhaust gas inlet and an exhaust gas outlet, and a reaction promoting gas introduced into the closed reaction chamber. It is characterized by comprising gas introducing means, vacuum means for making the closed reaction chamber a vacuum atmosphere, and plasma generating means for generating plasma in the closed reaction chamber.

As a preferred embodiment, a cooling means for increasing the reaction rate of the plasma reaction in the closed reaction chamber is provided, and the cooling means is structured to cool the plasma electrode.

In the present invention, a vacuum atmosphere between a pair of plasma electrodes arranged in parallel and opposed to each other at a predetermined interval is utilized by utilizing a vacuum atmosphere obtained by an existing pump system as a vacuum means or a newly installed pump system. During the process, the exhaust gas discharged from the semiconductor manufacturing process and the like are introduced, and a reaction-promoting gas is supplementarily introduced by a gas introduction means. Apply energy.

As a result, plasma is generated in a vacuum atmosphere between the two plasma electrodes, and the components of the exhaust gas are excited and activated together with the reaction promoting gas to react with each other. The plasma reaction product is stably deposited and solidified on the surface of the exhaust gas, and as a result, the harmful and polluting substances in the exhaust gas are decomposed and removed.

That is, a large amount of a reaction gas is supplied to a semiconductor manufacturing process or the like for the purpose of promoting a reaction with the highest possible efficiency, and the above-mentioned exhaust gas contains a reaction product gas newly generated by the reaction consumption. In addition, a large amount of unreacted gas and residual gas discharged without being consumed by reaction is included.

Accordingly, as the reaction promoting gas, a gas corresponding to the constituents of the exhaust gas, for example, the same as the reaction promoting gas supplied together with the reaction gas in the semiconductor manufacturing process or an appropriate catalyst gas having a catalytic effect is used. Thereby, the interaction between the reaction promoting gas and the plasma promotes dissociation and polymerization of the constituent material molecules, and causes an efficient gas phase chemical reaction (oxidation, hydrogen reduction, substitution reaction, etc.).
As a result, on the surface of the plasma electrode, the harmful and polluting substances in the exhaust gas are deposited and solidified as stable plasma reaction products, and are decomposed and removed from the exhaust gas. In this case, the reaction rate of the plasma reaction, that is, the deposition rate of the plasma reaction product is increased by cooling the plasma electrode by a suitable cooling means such as water cooling.

When the exhaust gas discharged from the semiconductor manufacturing process or the like is a mixed gas composed of a plurality of types of constituent materials, a plurality of closed reaction chambers for causing the plasma reaction are arranged in series, and each closed reaction chamber is provided. In the vacuum atmosphere of the room,
The reaction promoting gases of the type selected by the gas introducing means are individually introduced, and sequentially passed through the vacuum atmosphere of the continuous closed reaction chamber, thereby selectively dissociating the constituent substance molecules in the mixed gas. , By polymerization, and can be individually removed as various plasma reaction products.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 shows a schematic configuration of an exhaust gas treatment apparatus according to the present invention.
As shown in FIG. 4, the exhaust gas treatment apparatus 1 is specifically arranged between a reaction chamber 3 of a semiconductor manufacturing apparatus 2 and a vacuum pump 4 of a pump system for making the inside of the reaction chamber 3 a vacuum atmosphere. Then, the constituent substances in the exhaust gas discharged from the reaction chamber 3 are solidified by reaction.

The exhaust gas treatment apparatus 1 comprises a reaction section 5, a reaction promoting gas introduction section 6, a vacuum pump 4, a plasma generation section 7 and a cooling section 8 as main parts, and the vacuum pump 4 is shared with the semiconductor manufacturing apparatus 2. It is configured to be.

The reaction section 5 has two reaction units 10, 10 arranged in parallel. As shown in FIG. 2, the reaction unit 10 includes four reaction vessels 11a, 1
1b, 11c, and 11d are connected in series, and when the exhaust gas is a mixed gas composed of a plurality of types of constituent materials,
Each component can be removed individually.

That is, the four reaction vessels 11a to 11a
The reaction units 1d are integrally assembled with each other via a cooler 30 of a cooling unit 8 to be described later. An exhaust gas inlet 12a of the first reaction vessel 11a on the most upstream side is connected to an exhaust gas outlet 3a of the reaction chamber 3 in the semiconductor manufacturing process via an exhaust gas pipe 13a, while a fourth exhaust gas on the most downstream side is provided. Exhaust gas outlet 1 of reaction vessel 11d
2b is connected to the vacuum pump 4 via the exhaust gas line 13b. The reaction vessels 11a and 11b, 11b and 11c, and 11c and 11d, which are adjacent to each other, have an exhaust gas outlet 12b of an upstream reaction vessel connected to an exhaust gas inlet 12a of a downstream reaction vessel.

As a result, in FIG. 1, the exhaust gas pipe 1 is connected to the exhaust gas outlet 3a of the reaction chamber 3 in the semiconductor manufacturing process.
Exhaust gas discharged via 3a flows from the first reaction vessel 11a on the most upstream side to the second or third reaction vessels 11b to 11b.
After successively passing through four continuous reaction chambers A, A,... Up to 11d, they reach the vacuum pump 4 via an exhaust gas pipe 13b. 14 denotes a manual valve, 15
Indicates a pressure gauge.

Each of the reaction vessels 11a to 11d has a common basic structure as shown in FIG. 3. Specifically, the first most upstream reaction vessel 11a will be described below as an example.

The reaction vessel 11a is provided with the exhaust gas inlet 12
a and a closed reaction chamber A having an exhaust gas outlet 12b. In the closed reaction chamber A, as described later, plasma electrodes 20 and 21 of the plasma generator 7 are provided. An exhaust gas passage 16 extending to the discharge port 12b is formed. A cooler 30 is provided adjacent to the back surface of each of the plasma electrodes 20 and 21.

The reaction-promoting gas introduction section 6 is connected to each reaction vessel 11
a to 11d function as gas introduction means for introducing a reaction accelerating gas into the closed reaction chamber A. A gas introduction port 6a is provided at an appropriate position in the closed reaction chamber A so as to face the inside thereof. .. Are connected to a gas supply source through a pipe having a switching valve and the like, though not shown.

The gas supply source can appropriately and selectively supply a reaction accelerating gas corresponding to a constituent material of the exhaust gas to be treated. For example, the gas supply ports 6a, 6a, The same type of reaction promoting gas may be supplied to all of the.
It is also possible to supply different types of reaction promoting gas for each of a,. In particular, when the exhaust gas to be treated is a mixed gas composed of a plurality of types of constituent materials, the supply method as described above makes it possible to individually collect and remove each constituent material.

The following is an example of a reaction accelerating gas suitably used for the constituents of the exhaust gas to be treated.

Silane (Si) is used as the exhaust gas of the CVD system.
H ₄ ), titanium tetrachloride (TiCl ₄ ), tungsten hexafluoride (WF ₆ ), ammonia (NH ₃ ), dichlorosilane (SiH ₂ Cl ₂ ), arsine (AsH ₃ ), phosphine (PH ₃ ) or tribromide Although these gases contain boron (BBr ₃ ) and the like, a reaction promoting gas such as oxygen (O ₂ ), hydrogen (H ₂ ), water (H ₂ O), and air alone is contained in these exhaust gases. Alternatively, they are used by being appropriately mixed.

The exhaust gas of the etching system includes tetrafluoromethane (CF ₄ ) and boron trichloride (BC).
l ₃ ), silicon chloride (SiCl ₄ ), hydrogen bromide (HB
r), trifluoromethane (CHF ₃ ), nitrogen trifluoride (NF ₃ ), sulfur hexafluoride (SF ₆ ), etc., and these exhaust gases contain oxygen (O ₂ ), hydrogen (H ₂ ), water (H ₂ O), silane (Si
Reaction promoting gases such as H ₄ ) and carbon dioxide (CO ₂ ) are used alone or in a suitable mixture.

The vacuum pump 4 includes reaction vessels 11a to 11d
Function as vacuum means for making the inside of the closed reaction chambers A, A,... A vacuum atmosphere. In the present embodiment, as described above, the existing vacuum pump system for the reaction chamber 3 of the semiconductor manufacturing apparatus 2 is used. Things are shared as they are. With such a configuration, the equipment cost is reduced, the gas and by-products mixed into the pump oil used in the vacuum pump 4 are reduced, and the life of the pump oil is further reduced. The life of the system itself will also be extended.

The plasma generating unit 7 includes the reaction vessels 11a to 11a.
1d function as plasma generating means for generating plasma in the closed reaction chambers A, A,..., And include the above-described pair of plasma electrodes 20, 21 and a high-frequency oscillator 22.

The pair of plasma electrodes 20 and 21 are made of aluminum, and are arranged in parallel in the closed reaction chambers A at predetermined intervals.

Specifically, both plasma electrodes 20 and 21
Are interelectrode separators 25 made of an insulating material as partition members,
26, they are arranged and supported at predetermined intervals to form the walls of the reaction vessels 11a to 11d, and the space surrounded by them is a closed reaction chamber A. In the illustration, ceramic interelectrode separators 25 and 26 are used. This electrode separation plate 25 and the plasma electrode 2
The joint portions 0 and 21 are sealed by a sealing member 27 such as an O-ring, and
The exhaust gas inlet 12a and the gas inlet 6a are provided.

A plurality of thin plate-like electrode elements 20a, 20a,..., 21 extending in parallel to the other opposing plasma electrode are provided inside the two plasma electrodes 20, 21.
a, 21a,... respectively.

The electrodes 20a, 21a,... Of the plasma electrodes 20, 21 are arranged alternately and in parallel so as to intersect with each other. An exhaust gas passage 16 extending from the exhaust gas inlet 12a to the exhaust gas outlet 12b is formed. Thereby, the flat electrode surface of each of the electrode elements 20a and 21a functions as a surface for depositing and solidifying a reaction product by plasma, which will be described later, and secures a large effective electrode surface area.

More specifically, the electrodes 20a, 21a
Has a tapered cross-sectional shape as shown in FIG. Thus, the distance between the electrode surfaces of the two electrode elements 20a and 21a is set to be equal over the entire length of the exhaust gas flow path 16.

The high frequency oscillator 22 is connected to the plasma electrode 2
It is for applying high-frequency electric energy to 0 and 21 and is electrically connected to both electrodes. The high-frequency oscillator 22 oscillates electric energy having a frequency of 100 kHz to 13.56 MHz. The high-frequency oscillator 22 applies high-frequency electric energy to the plasma electrodes 20 and 21, and the exhaust gas passing between the plasma electrodes 20 and 21 is electronically excited. .

The cooling section 8 functions as a cooling means for increasing the reaction rate of the plasma reaction in each closed reaction chamber A.
1 is directly cooled.

The cooler 30 of the cooling unit 8 of the illustrated embodiment
Is a water-cooled cooler that uses cooling water as a refrigerant, and is disposed in contact with the outer back surfaces of the plasma electrodes 20 and 21 that constitute the walls of the reaction vessels 11a to 11d, and the cooling water and the electrode section The distance is configured to be as short as possible. Further, adjacent reaction vessels 11a to 11d are
The structure is such that one cooler 30 is shared.

In connection with this, the plasma electrodes 20,
21 includes a plurality of electrode elements 20a and 21a having a plurality of thin flat plates and a tapered cross-sectional shape as described above.
It has an electrode structure for efficiently transmitting the cooling temperature of the cooler 30.

Each of the coolers 30, 30,... Is connected to each other through a cooling water pipe (not shown). These cooling water pipes are connected to a cooling water inlet at an upstream end thereof as shown in FIG. 30a is connected to a cooling water supply source of the cooling unit 8 through a pipe 35a, and a cooling water outlet 30b at a downstream end.
Is drained out of the figure through the pipe 35b. 36 indicates a manual valve, and 37 indicates a flow meter.

In the exhaust gas treatment apparatus 1 configured as described above, the exhaust gas discharged from the reaction chamber 3 of the semiconductor manufacturing apparatus 2 is, as shown in FIG.
3a, the two reaction units 10, 1 of the reaction section 5
0 is introduced. Exhaust gas introduced into each reaction unit 10 is supplied to first to fourth reaction vessels 11 connected in series.
After passing sequentially through the closed reaction chambers A, 11b, 11c and 11d, they are discharged from the exhaust gas line 13b to the atmosphere or the like via the vacuum pump 4.

In each closed reaction chamber A, the exhaust gas flow path 16 formed between the electrodes 20 a, 21 a,... Of the plasma electrodes 20, 21 is brought into a vacuum atmosphere by the vacuum pump 4 and the gas introduction section 6. , A predetermined reaction promoting gas is introduced in an auxiliary manner, and high-frequency electric energy is applied to the plasma electrodes 20 and 21 by the high-frequency oscillator 22.

Thus, as shown in FIG. 3, the exhaust gas introduced from the exhaust gas inlet 12a is mixed with the reaction promoting gas and passes through the exhaust gas passage 16 in a vacuum atmosphere to the exhaust gas outlet 12b. , The electrodes 20a, 2
Plasma is generated in a vacuum atmosphere between 1a,..., And the constituents of the exhaust gas are excited and activated together with the reaction promoting gas to react, and the components of the electrode elements 20a, 21a,. The plasma reaction product is stably deposited and solidified on the electrode surface as a solid, and as a result, the harmful and polluting substances in the exhaust gas are decomposed and removed.

That is, since a large amount of reaction gas is supplied to the reaction chamber 3 of the semiconductor manufacturing apparatus 2 for the purpose of promoting a reaction with as high efficiency as possible, the above exhaust gas is newly generated by reaction consumption. In addition to the reaction product gas, it contains a large amount of unreacted gas and residual gas discharged without being consumed by the reaction.

Therefore, as the reaction promoting gas, one corresponding to the constituents of the exhaust gas, for example, the same as the reaction promoting gas supplied to the reaction chamber 3 together with the reaction gas, or an appropriate catalyst gas having a catalytic effect is used. By the interaction between the reaction promoting gas and the plasma,
Dissociation and polymerization of the constituent material molecules are promoted, and an efficient gas phase chemical reaction (oxidation, hydrogen reduction, substitution reaction, etc.) can be caused.

As a result, the harmful and polluting substances in the exhaust gas are deposited and solidified as stable plasma reaction products on the electrode surfaces of the electrodes 20a, 21a,... Of the plasma electrodes 20, 21 and decomposed from the exhaust gas. Will be removed. In this case, in the present embodiment, the electrode elements 20a,
Are cooled by the cooler 30, the reaction rate of the plasma reaction, that is, the deposition rate of the plasma reaction product is also increased.

In the illustrated embodiment, since a plurality of closed reaction chambers A for generating a plasma reaction are connected in series, the exhaust gas discharged from the semiconductor manufacturing apparatus 2 is a mixed gas comprising a plurality of types of constituent substances. In some cases, the reaction promoting gas of the type selected by the gas introduction unit 6 is individually introduced into the vacuum atmosphere of the exhaust gas passage 16 of each closed reaction chamber A, thereby achieving the target in the mixed gas. It is also possible to selectively dissociate and polymerize only the constituent substance molecules and individually remove them as various plasma reaction products.

Since the exhaust gas treatment apparatus 1 is installed between the semiconductor manufacturing apparatus 2 and the vacuum pump 4 of the vacuum pump system as in this embodiment, not only air pollution and the like are prevented, The gas and by-products mixed in the oil used in the vacuum pump 4 are reduced, and the service life of the vacuum pump 4 is improved, and the operation rate of the vacuum pump 4 is improved. Can be extended.

Embodiment 2 This embodiment is shown in FIG. 5, in which, when the driving capacity of the existing vacuum pump 4 of the semiconductor manufacturing apparatus 1 is small, a separate and independent vacuum pump 104 is provided in the exhaust gas treatment apparatus 1. It is provided with.

That is, the reaction section 5 of the exhaust gas treatment device 1
Is disposed downstream of a vacuum pump 4 that evacuates the reaction chamber 3 of the semiconductor manufacturing apparatus 2 to a vacuum atmosphere, and the vacuum pump 104 is disposed downstream of the reaction section 5. The vacuum pump system that drives the vacuum pump 104 may be shared with the vacuum pump 4 of the semiconductor manufacturing apparatus 2 or may be independent.

However, with such a configuration, a stable optimum degree of vacuum can always be obtained in the reaction section 5 of the exhaust gas treatment apparatus 1 regardless of the performance of the semiconductor manufacturing apparatus 2. Other configurations and operations are the same as those of the first embodiment.

The following is a specific example to which the exhaust gas treatment apparatus 1 of the above embodiment is applied. Embodiment 1 In this embodiment, the above-described exhaust gas treatment apparatus 1 is applied when silane gas (SiH ₄ ) is used in a semiconductor manufacturing process by a CVD method.

When silane gas (SiH ₄ ) is used in CVD, oxygen (O ₂ ) is usually introduced into the reaction chamber 3 at the same time, so that a large amount of silane is not contained in the exhaust gas from the reaction chamber 3. It remains as a reaction. Therefore, in order to promote a plasma reaction with respect to this residual gas, a large amount of oxygen (O ₂ ) is mixed into these exhaust gases as a reaction promoting gas.

Thus, in the reaction section 5, the exhaust gas undergoes the same reaction as the CVD in the reaction chamber 3, and the concentration of the silane-based exhaust gas can be reduced.

Embodiment 2 In this embodiment, diborane (B ₂ H ₆ ), phosphine (PH ₃ ), and arsine (ASH ₃ ) are mixed in a silane gas (SiH ₄ ) in a semiconductor manufacturing process by a CVD method. In addition, the above-mentioned exhaust gas treatment apparatus 1 is applied.

In this case, an oxide such as silicon dioxide doped as a plasma reaction product is deposited and solidified, thereby enabling removal.

Embodiment 3 In this embodiment, the above-mentioned exhaust gas treatment apparatus 1 is applied when fluorine gas is mixed in the exhaust gas from the reaction chamber 3 of the semiconductor manufacturing apparatus 2 of the etching system.

In this case, the reaction product gas generated by the reaction of the fluorine gas with the object to be etched may be dissociated by the plasma reaction of the reaction part 5, and hydrofluoric acid (HF) may be newly generated. For this reason, the reaction vessels 11a to 11d
By converting a part of the wall material to silicon (Si) or polycrystalline silicon, forcing this syringe to react with the formed hydrofluoric acid, silicon tetrafluoride (SiF ₄ ) and hydrogen (H ₂ )
The production of hydrofluoric acid is reduced.

Embodiment 4 In this embodiment, as in Embodiment 1, the above exhaust gas treatment apparatus 1 is applied when silane gas (SiH ₄ ) is used in a semiconductor manufacturing process by a CVD method.

In this case, in the configuration of Embodiment 1, FIG.
As shown in (1), a reaction chamber B for forcibly reacting silane gas and oxygen is disposed upstream of the reaction section 5 of the exhaust gas treatment apparatus 1. Other configurations and operations are the same as those of the first embodiment.

The above-described embodiments merely show preferred embodiments of the present invention, and the present invention is not limited to these, and various design changes can be made within the scope. As an example, the following modifications can be considered.

(1) In the illustrated embodiment, the reaction section 5
Is provided in parallel with two reaction units 10, 10, and the number of the reaction units 10 is set according to the required amount of exhaust gas discharged from the semiconductor manufacturing apparatus 2. When the required processing amount is small, the amount is appropriately increased or decreased according to the purpose, such as a single reaction unit 10.

(2) Similarly, the reaction unit 10 of the illustrated embodiment has four reaction vessels 11a, 11b, 11c, 1
1d is connected in series, and when the exhaust gas is a mixed gas composed of a plurality of types of constituent substances, each constituent substance can be individually removed. It may be appropriately increased or decreased according to the purpose, and may be constituted by a single reaction vessel, that is, a single vacuum atmosphere.

(3) The specific configuration of the plasma electrodes 20 and 21, especially the specific configuration of the electrode elements 20a and 21a, is not limited to the illustrated embodiment. For example, the illustrated electrode 20
Reference numerals a and 21a denote thin-walled flat plates which alternately intersect in parallel and have a structure capable of removing and removing plasma reaction products deposited and solidified on the surfaces of these electrodes.
Although the repeated use of 0 and 21 is ensured, concentric spiral shapes or the like intersecting concentrically and in parallel can be adopted. In this case, the disposable structure is used as a cartridge for collecting plasma reaction products. You.

(4) The present invention is applicable to the treatment of exhaust gas in a semiconductor manufacturing apparatus as shown in the illustrated embodiment, and in a similar apparatus for forming or etching using a reaction gas.

[0070]

As described in detail above, according to the present invention,
In a vacuum atmosphere, while generating a plasma while mixing the reaction promoting gas with the exhaust gas discharged from the semiconductor manufacturing process and the like, the constituent substances in the exhaust gas are deposited and solidified as a plasma reaction product. By selecting the most suitable reaction accelerating gas in accordance with the constituents of the exhaust gas to be treated, the exhaust gas discharged from various semiconductor manufacturing processes, etc. is processed, and the harmful and polluting substances contained therein Can be substantially completely decomposed and removed.

That is, the exhaust gas from the semiconductor manufacturing process or the like contains a large amount of unreacted gas and residual gas discharged without being consumed by reaction, in addition to the reaction product gas newly generated by reaction consumption. However, as the reaction promoting gas, for example, by using the same reaction promoting gas supplied together with the reaction gas in the semiconductor manufacturing process or an appropriate catalyst gas having a catalytic effect, the reaction promoting gas and the plasma are used. The interaction promotes the dissociation and polymerization of the constituent molecules, causing an efficient gas phase chemical reaction.As a result, on the surface of the plasma electrode, the harmful and polluting substances in the exhaust gas become stable plasma reaction products. It can be solidified and decomposed and removed from the exhaust gas. Thus, even if the exhaust gas is directly discharged to the atmosphere, the problem of air pollution does not occur.

Further, by interposing the above-mentioned vacuum atmosphere between a reaction vessel in a semiconductor manufacturing process or the like and a vacuum pump system thereof, purified exhaust gas is sent into the vacuum pump system, and as a result, pump oil is reduced. The life of the pump oil and the life of the vacuum pump system itself are prolonged without being deteriorated by reacting with untreated substances in the exhaust gas.

When the exhaust gas discharged from the semiconductor manufacturing process or the like is a mixed gas composed of a plurality of types of constituent materials, a plurality of closed reaction chambers for causing the plasma reaction are arranged in series, and The reaction promoting gas of the type selected by the gas introducing means is individually introduced into the vacuum atmosphere of the reaction chamber, and sequentially passed through the vacuum atmosphere of the continuous closed reaction chamber, whereby It is also possible to selectively dissociate and polymerize constituent material molecules and individually remove them as various plasma reaction products.

Further, by cooling the electrode surface of the plasma electrode by the cooling means, the reaction rate of the plasma reaction in a vacuum atmosphere, that is, the deposition rate of the plasma reaction product is increased, and more efficient exhaust gas treatment is realized. I can do it.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an exhaust gas treatment apparatus according to a first embodiment of the present invention.

FIG. 2 shows a reaction unit of the exhaust gas treatment apparatus, and FIG.
2A is a plan view showing a partial cross section, FIG. 2B is a front view showing the same partial cross section, and FIG. 2C is a right side view.

FIG. 3 is an enlarged longitudinal sectional view showing an internal configuration of a reaction vessel of the reaction unit.

FIG. 4 is a block diagram showing a connection system of the exhaust gas treatment device.

FIG. 5 is a block diagram illustrating a connection system of an exhaust gas treatment device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a modification of the reaction section of the exhaust gas treatment apparatus of the present invention.

[Explanation of symbols]

Reference Signs List A Closed reaction chamber 1 Exhaust gas treatment device 2 Semiconductor manufacturing device 3 Semiconductor manufacturing device reaction chamber 4 Vacuum pump (vacuum means) 5 Reaction unit 6 Reaction promoting gas introduction unit (gas introduction unit) 6a Gas introduction port 7 Plasma generation unit (plasma) Generation means) 8 Cooling unit (Cooling means) 10 Reaction unit 11a to 11d Reaction vessel 12a Exhaust gas inlet 12b Exhaust gas outlet 20, 21 Plasma electrode 20a, 21a Electrode of plasma electrode 22 High frequency oscillator 30 Cooler 104 Vacuum pump

Claims (10)

[Claims] In a vacuum atmosphere, a plasma is generated while mixing a reaction promoting gas with an exhaust gas discharged from a semiconductor manufacturing process or the like, so that constituents in the exhaust gas are deposited and solidified as a plasma reaction product. An exhaust gas treatment method, characterized in that: 2. The exhaust gas according to claim 1, wherein a plasma electrode for generating plasma is arranged in the vacuum atmosphere, and the plasma reaction product is deposited and solidified on the surface of the plasma electrode. Processing method. 3. An exhaust gas discharged from a semiconductor manufacturing process or the like is sequentially passed through a plurality of vacuum atmospheres, and a plasma is generated in each vacuum atmosphere while mixing a selected reaction promoting gas with the gas. The exhaust gas treatment method according to claim 1 or 2, wherein the constituent substances in the exhaust gas are deposited and solidified as a plasma reaction product. 4. The method according to claim 1, wherein the surface of the plasma electrode is cooled during the treatment of the exhaust gas to promote the solidification of the constituents in the exhaust gas. Exhaust gas treatment method. 5. An apparatus for reacting and solidifying constituents in exhaust gas discharged from a semiconductor manufacturing process or the like, comprising: a sealed reaction chamber having an exhaust gas inlet and an exhaust gas outlet; An exhaust gas treatment apparatus comprising: a gas introduction unit to be introduced; a vacuum unit configured to create a vacuum atmosphere in the closed reaction chamber; and a plasma generation unit configured to generate plasma in the closed reaction chamber. 6. The plasma generating means includes a pair of plasma electrodes disposed in parallel and opposed to each other at a predetermined interval in the closed reaction chamber, and a high-frequency oscillator for applying high-frequency electric energy to these plasma electrodes. The high-frequency oscillator is configured to apply high-frequency electric energy to the plasma electrode to electronically excite a constituent material of exhaust gas passing between the two plasma electrodes. 6. The exhaust gas treatment device according to 5. 7. The reaction promoting gas introduced into the closed reaction chamber by the gas introducing means is selected according to a constituent material of an exhaust gas to be treated.
Or the exhaust gas treatment apparatus according to 6. 8. The apparatus according to claim 5, further comprising cooling means for increasing a reaction rate of the plasma reaction in the closed reaction chamber, wherein the cooling means has a structure for cooling the plasma electrode. An exhaust gas treatment apparatus according to any one of claims 7 to 13. 9. The closed reaction chamber is disposed between a reaction chamber of a semiconductor manufacturing apparatus or the like and a pump system for making the reaction chamber a vacuum atmosphere, and the pump system makes the closed reaction chamber a vacuum atmosphere. The exhaust gas treatment apparatus according to any one of claims 5 to 9, wherein the apparatus is configured to function as a vacuum means. 10. A structure in which a plurality of the closed reaction chambers are arranged in series, and the exhaust gas discharged from a semiconductor manufacturing process or the like sequentially passes through a vacuum atmosphere formed in the closed reaction chambers. The exhaust gas treatment according to any one of claims 5 to 9, wherein a reaction promoting gas selected by the gas introduction means is individually introduced into a vacuum atmosphere of each closed reaction chamber. apparatus.