JP2002153729A - Method and device for halogen-containing gas treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method and device for halogen-containing gas capable of decomposing and treating a halogen compound in a high effi ciency not depending on a concentration of halogen in the halogen compound- containing gas. SOLUTION: The predetermined amount of water vapor based on a concentration of halogen in a halogen-compound-containing gas in mixed into the halogen compound-containing gas. This mixture gas is introduced to a discharge processing part 31 to decompose the halogen compound in the mixture gas. This decomposed product is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating a halogen-containing gas, and more particularly to a method for treating a halogen-containing gas with high efficiency irrespective of the halogen concentration in the halogen compound-containing gas. It is.

[0002]

2. Description of the Related Art In a dry etching apparatus used for manufacturing semiconductors, halogen compounds such as CF ₄ and SF ₆ are mainly used as an etching gas for a silicon-based thin film. In the CVD apparatus, the same halogen compound as described above is used for the purpose of cleaning the processing chamber by etching a film deposited in the processing chamber. Most of the halogen compounds are global warming substances having a long life in the atmosphere and having a global warming potential of several thousands to tens of thousands of times that of carbon dioxide (CO ₂ ). Further, a halogen compound containing a chlorine atom in the molecule is also an ozone layer depleting substance. Therefore, for the purpose of preventing global warming and destruction of the ozone layer, research on a processing method for removing a halogen-containing gas containing these halogen compounds from exhaust gas of a semiconductor factory or the like is being advanced.

FIG. 11 is a view for explaining the configuration of a conventional processing apparatus for a halogen-containing gas disclosed in Japanese Patent Application Laid-Open No. 11-156156. A conventional halogen-containing gas processing apparatus will be described with reference to FIG. The apparatus for processing a halogen-containing gas includes a discharge processing unit 2 connected to a gas discharge source 1 such as a dry etching apparatus for discharging a halogen-containing gas. The discharge processing unit 2 is provided with a pair of discharge electrodes 4 and 5 facing each other in a chamber 3. One of these electrodes is connected to a high-frequency power supply 6, and the other is grounded. The discharge processing section 2 has a water vapor generator 7 connected to the processing gas introduction side.
It is configured so that it can be introduced in between. The discharge side of the discharge processing unit 2 is connected to a bubbling device 8 that is a product collector, and is configured to discharge gas discharged from the discharge processing unit 2 into water 9 in the bubbling device 8. I have.

In the conventional method for treating a halogen-containing gas, the discharged halogen-containing gas and the steam from the steam generator 7 are introduced between the discharge electrodes 4 and 5 to generate a gas discharge at atmospheric pressure. Let it. By this discharge, CF ₄ and water are dissociated by the energy of electrons, and hydrogen fluoride (HF) and carbon dioxide (CO ₂ ) are generated. Thereafter, these gases are led to a bubbling device 8, where hydrogen fluoride generated by bubbling in the water 9 and discharged is dissolved in the water and collected.

[0005]

However, the conventional c
In a processing device for a logen-containing gas, CF in exhaust gas is used.
_FourDepending on the concentration of CF_FourThat the decomposition efficiency of
There was a title. The present invention solves such a problem.
Especially for halogen-containing gas.
Global warming substances or
Highly efficient decomposition of halogen compounds, which are ozone depleting substances
Method and apparatus for processing halogen-containing gas that can be processed
The purpose is to gain.

[0006]

According to a method for treating a halogen-containing gas according to the present invention, a halogen compound-containing gas is mixed with a predetermined amount of water vapor based on the halogen concentration in the gas, and the mixed gas is discharged to a discharge treatment section. To decompose the halogen compound in the mixed gas to remove the decomposition products.

Further, the mixing of the halogen compound-containing gas with a predetermined amount of water vapor is performed by gas-liquid contact between the halogen compound-containing gas and an aqueous medium controlled at a predetermined temperature.

Further, the gas-liquid contact is carried out by discharging a halogen compound-containing gas into an aqueous medium and performing bubbling.

Further, the gas-liquid contact is carried out by contacting a halogen compound-containing gas with an aqueous medium to be dropped.

Water vapor is mixed so that the ratio of the concentration of water molecules to the concentration of halogen atoms in the mixed gas is 0.25 to 1.

A predetermined amount of water vapor is mixed with a halogen compound-containing gas supplied via a vacuum pump, and a rare gas is used as a purge gas for the vacuum pump.

Further, the mixed gas is introduced into the electric discharge treatment section through a pipe, and the temperature of the pipe is set at 5 ° C. lower than the temperature of the aqueous medium.
The temperature is adjusted higher.

Further, the temperature of the electrode of the discharge treatment section is controlled to be higher than the temperature of the aqueous medium by 5 ° C. or more.

Further, the mixing of the halogen compound-containing gas with a predetermined amount of water vapor is performed after adding a water vapor in excess of a predetermined amount to the halogen compound-containing gas, and then adding the water vapor added gas based on the halogen concentration in the halogen compound-containing gas. This is performed by adjusting the temperature to a predetermined temperature.

The apparatus for treating a halogen-containing gas according to the present invention comprises a steam supply section for controlling mixing of a predetermined amount of steam based on the halogen concentration in the halogen compound-containing gas, and a halogen compound-containing gas and a steam supply section. A discharge processing unit that decomposes the mixed gas with the mixed water vapor by discharge.

Further, a water vapor supply section controls the aqueous medium to a predetermined temperature based on a gas-liquid contact section in which the halogen compound-containing gas and the aqueous medium come into gas-liquid contact with each other and a halogen concentration in the halogen compound-containing gas. A temperature control unit.

Further, the gas-liquid contact section has a bubbling section for bubbling by discharging the halogen compound-containing gas into the aqueous medium.

Further, the gas-liquid contact section has an aqueous medium dropping section for dropping the aqueous medium, and a contact section for contacting the halogen compound-containing gas with the aqueous medium dropped from the aqueous medium dropping section. .

Further, the halogen concentration in the halogen compound-containing gas is detected by a halogen concentration sensor.

[0020] Further, the apparatus has a collection unit for capturing the decomposition products generated in the discharge processing unit in the aqueous medium by discharging the gas that has passed through the discharge processing unit into the aqueous medium and performing bubbling.

Further, a temperature control section is provided in a pipe connecting the steam supply section and the discharge processing section.

The discharge processing section includes a heating source for heating the discharge electrodes.

Further, a steam supply unit for mixing steam into the halogen compound-containing gas, and a mixed gas of the halogen compound-containing gas and the steam mixed by the steam supply unit, which is connected to the steam supply unit and a pipe, are decomposed by electric discharge. And a temperature control unit provided in at least a part of the pipe and controlling the halogen-containing gas containing water vapor to a predetermined temperature based on the halogen concentration of the halogen compound-containing gas.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram illustrating a configuration of a halogen-containing gas processing apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 11 denotes a discharge source of a halogen compound-containing gas, 21 denotes a steam supply unit that mixes steam with the halogen compound-containing gas discharged from the discharge source 11,
Reference numeral 31 denotes a discharge processing section for a halogen compound-containing gas mixed with water vapor, and 41 denotes a collection section for decomposition products generated by decomposition of the halogen compound.

The discharge source 11 is a dry etching device or a CV
As a vacuum pump for evacuating the reaction processing chamber 12 of the D apparatus and the gas in the reaction processing chamber 12, for example, a turbo molecular pump 13
And a dry pump 14. The turbo molecular pump 13 and the dry pump 14 are respectively provided with purge gas introduction portions 15 and 16 for protecting the pumps.

The water vapor supply section 21 is provided with a bubbling container 22 containing an aqueous medium 23. The gas discharged from the discharge source 11 is introduced into the aqueous medium 23 so that the gas discharged from the discharge source 11 can be bubbled. A pipe 24 is provided from the side. Normally, water is used as the aqueous medium 23, but additives may be added. A halogen concentration sensor 25 is provided in the middle of the pipe 24. In addition, the bubbling container 22 includes a temperature sensor 26 for detecting the temperature of the aqueous medium 23 and a temperature controller 27 for controlling the aqueous medium 23 to a predetermined temperature based on the detected temperature. In a space above the aqueous medium 23 in the bubbling container 22, a pipe 28 for guiding the bubbled gas to the discharge processing unit 31 is provided.

In the discharge processing section 31, a pair of electrodes 33 and 34 are provided in a chamber 32, and one of the pair of discharge electrodes 33 and 34 is connected to a high-voltage power supply 35, and the other is connected to the other. Grounded. Further, the discharge electrode 33,
In order to control the temperature of the electrode 34 to a predetermined temperature, a circulating liquid flows through each electrode by a liquid temperature regulator 36 and a circulating pump 37.

The collecting section 41 for capturing hydrogen halide, which is a decomposition product, is provided in a bubbling vessel 4 containing an aqueous medium 43.
A pipe 44 is provided from the discharge side of the chamber 32 of the discharge processing unit 31 so that the gas decomposed by the discharge processing unit 31 can be discharged and bubbled into the aqueous medium 43. Normally, water is used as the aqueous medium 43. Further, in a space above the aqueous medium 43 in the bubbling container 42, a pipe 45 for discharging the bubbled gas is provided.

Using such a halogen-containing gas treatment apparatus, the decomposition efficiency of halogen compounds was examined. FIG. 2 is a diagram showing the result of examining the pure water temperature and the CF ₄ decomposition efficiency when pure water is used as the aqueous medium of the steam supply section in the present invention. The measurement conditions are discharge power 1k applied to the discharge electrode.
W, a nitrogen gas having a gas flow rate of 1 l / min was introduced as a purge gas into the vacuum pump, and the gas concentration of CF ₄ was 0.5%,
% And 2%. From this experiment, it was found that the optimum water temperature changes depending on the CF ₄ gas concentration. The optimal water temperature increased as the gas concentration of CF ₄ increased. When the concentration of CF ₄ is 5000 ppm, 0 ° C. to 20 ° C., preferably 6 ° C. to 12 ° C., 100 ° C.
When the amount is 00 ppm, the temperature is 15 ° C to 30 ° C, preferably 20 ° C.
25 ° C to 25 ° C and 20,000 ppm, 25 ° C to 40 ° C
° C, preferably 30 ° C to 35 ° C.

As a result of further experiments, CF_FourDecomposition effect of
The percentage is the saturated moisture that the halogen-containing gas brings into the discharge treatment section.
Concentration and CF_FourIt is determined that it is uniquely determined by the concentration
The bright men found them. FIG. 3 shows the CF according to the present invention._Four
Ratio of saturated water concentration to concentration and CF_FourOf decomposition efficiency
It is a figure showing the result of having examined the relation. As shown in FIG.
To saturated water concentration and CF_FourAre in the range of 1: 1 to 4: 1.
Enclosure, preferably a range of 2: 1 to 3: 1 is effective
Was revealed. It is thought that the cause is as follows
You. That is, if the supplied water amount is small, the decomposed C or F
Recombined and CF _FourAnd the decomposition efficiency decreases. On the other hand,
If the amount of water supply is too large, the energy of electrons will be
Energy is consumed ineffectively and the decomposition efficiency is reduced. In this invention
According to CF_FourWater medium that bubbles even when the concentration of
Achieve high decomposition efficiency by optimizing body temperature
can do.

Further, as a result of further detailed examination, it has been found that the optimum amount of water is uniquely determined by the amount of fluorine atoms (F) in CF ₄ . FIG. 4 shows the ratio of the saturated water concentration to the F atom concentration and CF ₄ in the present invention.
FIG. 6 is a view showing the result of examining the relationship between the decomposition efficiencies. From FIG. 4, the ratio of the saturated water concentration to F in CF ₄ is 0.25: 1.
~ 1: 1 range, desirably 0.5: 1 to 0.75: 1.
Range was found to be effective.

Further, C ₂ F ₆ , NF ₃ , SF ₆ , CCIF
₃ , CHF ₃ , CHClF ₂ , CBrF ₃ , CCl ₄ , CH ₃
A similar experiment was conducted with other halogen compound-containing gases such as CCl ₃ , and it was found that the optimum amount of water was uniquely determined by the ratio of the concentration of water molecules to the concentration X converted to the number of halogen atoms. It became. FIG. 5 is a graph showing the results of an examination of the relationship between the ratio of the concentration of water molecules to the concentration of halogen atoms and the decomposition efficiency of CF ₄ in the present invention. From FIG. 5, the ratio of the water molecule concentration to the halogen atom concentration is 0.2
5: 1 to 1: 1, preferably 0.5: 1 to 0.7
A range of 5: 1 has been found to be optimal.

Next, a method for treating a halogen-containing gas according to the first embodiment of the present invention will be described. The reaction processing chamber 12
The gas is exhausted by the turbo molecular pump 13 and the dry pump 14, and the etching reaction product and the halogen compound-containing gas including the CF ₄ gas are exhausted from the outlet side of the dry pump 14. In order to prevent corrosion due to exhaust gas and clogging of pipes, the turbo molecular pump 13 and the dry pump 14 have purge gas introduction sections 15 and 16 provided in each pump.
Nitrogen gas is introduced as a purge gas.

The exhaust gas from the reaction processing chamber 12 is introduced into the aqueous medium 23 in the bubbling container 22 through the pipe 24 together with the purge gas. A halogen concentration sensor 25 for detecting the halogen concentration in the gas is provided in the middle of the pipe 24, so that the halogen concentration in the gas can be accurately obtained. Based on the concentration detected by the halogen concentration sensor 25, the temperature of the aqueous medium 23 into which the amount of water vapor having the highest decomposition efficiency can be mixed is determined. The temperature adjuster 27 adjusts the temperature of the aqueous medium 23 while detecting the temperature of the aqueous medium 23 with the temperature sensor 26 so that the aqueous medium 23 has this temperature. By discharging the exhaust gas into the aqueous medium 23 and performing bubbling, hydrogen halide and unstable reaction products in the exhaust gas are dissolved in the aqueous medium 23, and the CF ₄ gas and the purge gas pass through the pipe 28. To the chamber 32 of the discharge processing unit 31. At this time, by bubbling in the aqueous medium 23, steam having a saturated moisture concentration corresponding to the temperature of the aqueous medium 23 is mixed into the CF ₄ gas and the purge gas. By such a method, a predetermined amount of steam can be easily supplied.

The gas guided to the chamber 32 passes between the pair of electrodes 33 and 34. At this time, a pair of electrodes 33,
Between 34, a high voltage is applied by a high voltage power supply 35,
Discharge occurs between the pair of electrodes 33 and 34, and high-energy electrons are generated. By high energy electrons than the dissociation energy of CF bond of CF ₄ collides with the CF _4, degrade hardly degradable CF ₄ is as the following equation (1). Here, the addition of steam removes the decomposed carbon and fluorine as represented by the following formula (2). CF ₄ + e → C + 4F + e (1) CF ₄ + 2H ₂ O + e → CO ₂ + 4HF + e (2)

The pair of electrodes 33 and 34 are provided with a liquid temperature controller 36.
And the temperature of the aqueous medium 23 by 5
The heating is controlled to a temperature higher by at least 10 ° C, preferably by at least 10 ° C. Accordingly, it is possible to prevent the occurrence of an accident such as a stop of discharge due to dew condensation on the surfaces of the pair of electrodes 33 and 34 and a short-circuit at a part of the electrodes to cause breakage, thereby enabling a stable treatment.

The carbon dioxide (CO ₂ ), hydrogen fluoride (HF), and nitrogen of the purge gas generated by the above equation (2) are led to the collection unit 41 through the pipe 44. The gas discharged from the discharge processing unit 31 is released into the aqueous medium 43 in the bubbling container 42 and is bubbled. Hydrogen fluoride (HF) is dissolved in the aqueous medium 43 and collected as hydrofluoric acid. Carbon dioxide (CO ₂ ) and purge gas are released into the atmosphere.

In the treatment of the halogen-containing gas as described above, a predetermined amount of water vapor that maximizes the decomposition efficiency of the halogen compound is mixed with the halogen-containing gas based on the halogen concentration in the exhaust gas. Halogen compounds, which are global warming substances or ozone depleting substances, can be decomposed with high efficiency regardless of the halogen concentration, and hydrogen halide, which is a decomposition product, can be collected and removed.

In the above method, the halogen concentration is detected using the halogen concentration sensor 25, and the set temperature of the aqueous medium 23 is determined based on the detected halogen concentration. The set temperature of the aqueous medium 23 may be determined by calculating the halogen concentration from the compound concentration and the purge gas flow rate. In this case, the halogen concentration sensor 25
Can be eliminated, and the cost of the processing apparatus can be reduced.

In the above method, the collecting section 41 is provided on the outlet side of the discharge processing section 31, but in many semiconductor factories,
A method is adopted in which hydrogen halide is treated at once in a factory by acid exhaust. In such a case, it is not necessary to provide the collecting section 41 on the outlet side of the discharge processing section 31, and the outlet side of the discharge processing section 31 is directly connected to the acid exhaust equipment of the factory to collect hydrogen halide. be able to.

In the above method, water is used as the aqueous medium 43 of the collecting section 41, but an aqueous solution of calcium hydroxide may be used. In this case, since it can be recovered as calcium fluoride, post-treatment is easy.

In the above description, CF ₄ was described as a halogen compound.
C ₂ F ₆ , NF ₃ , SF ₆ , CCIF ₃ , CHF ₃ , CHCl
F ₂ , CBrF ₃ , CCl ₄ , CH ₃ CCl ₃ or the like may contain fluorine (F) or chlorine (Cl) as a halogen in the molecule. It can also be used for treating halogen-containing gases containing these halogen compounds.

Embodiment 2 In the above description, nitrogen gas was used as the purge gas for the vacuum pump. However, in this case, the nitrogen gas is decomposed in the discharge processing unit 31, and when the exhaust gas contains oxygen, it is combined with the oxygen gas to generate nitrogen oxides (NO _x ). In particular, when the oxygen concentration was low, most of the generated NO _x was N ₂ O. The main purpose of the present invention is to remove the halogen compound is a greenhouse gas, but the halogen-containing gas processing is ended and generates NO _x as a new greenhouse gases be removed halogen compound The effect of providing the device is diminished.

Therefore, in the second embodiment, a rare gas such as helium, neon, argon, krypton, or xenon is used as the purge gas for the vacuum pump instead of the nitrogen gas. FIG. 6 is a diagram showing an example of a result obtained by examining a relationship between a purge gas flow rate and a decomposition efficiency of a halogen-containing gas when various purge gases are used. In FIG. 6, CF ₄ as a halogen compound was flowed at a constant flow rate of 0.1 l / min to change the flow rate of the purge gas. When nitrogen (N ₂ ), air (AIR), or oxygen (O ₂ ) gas was used as the purge gas, the halogen compound decomposition efficiency sharply decreased as the purge gas flow rate increased. Moreover, in the case where the nitrogen and air with purge gas produced a large amount of NO _x. on the other hand,
Helium (He), neon (N
e) When argon (Ar) was used, the decomposition efficiency of the halogen compound was not extremely reduced even when the flow rate of the purge gas was increased. Furthermore, there was no generation of NO _x . The same applies when other rare gases such as krypton and xenon are used. The reason why the degradation of the decomposition efficiency is small when the rare gas is used as the purge gas is presumed to be that the electron energy is not wasted by the collision between the electrons and the rare gas.

As described above, by using a rare gas as the purge gas for the vacuum pump, even when the flow rate of the purge gas is increased, the efficiency of decomposition of the halogen compound is small, and it is smaller than that of the nitrogen gas which is generally used. Has high decomposition efficiency. It is also superior in that it does not generate harmful substances such as NO _x. Among the rare gases, argon has the advantage of being the least expensive.

Embodiment 3 FIG. 7 is a diagram illustrating a configuration of a halogen-containing gas processing apparatus according to Embodiment 3 of the present invention. The configuration of the halogen-containing gas processing apparatus of the third embodiment is different from that of the first embodiment in that a temperature sensor 26 for controlling the temperature of the aqueous medium 23 and a temperature controller 27 are not provided in the pipe 28 without providing a temperature controller. Is that a gas temperature controller 51 is provided. Except for this point, the third embodiment is the same as the first embodiment. In the third embodiment, the temperature of the mixed gas of the halogen compound-containing gas and the steam is adjusted to a predetermined temperature equal to or lower than the temperature of the aqueous medium 23 by the gas temperature controller 51. As the gas temperature controller 51, a normal heat exchanger or the like is used.
As a result, an excessive amount of water vapor in the mixed gas flowing in the pipe 28 is cold trapped, and the gas temperature controller 51
The mixed gas that has passed through contains a saturated water vapor amount corresponding to the temperature cooled by the gas temperature controller 51. Thus, also in the present embodiment, the amount of water vapor in the mixed gas of the halogen compound-containing gas and the water vapor can be controlled to a predetermined amount, so that the halogen compound can be decomposed with high efficiency. In particular, in the present embodiment, since the temperature of the aqueous medium 23 is not regulated, the temperature of the aqueous medium 23 is usually room temperature, which is suitable as a method for controlling and adding a small amount of water vapor less than the saturated water vapor amount at room temperature. ing.

Embodiment 4 FIG. 8 is a diagram illustrating a configuration of a halogen-containing gas processing apparatus according to Embodiment 4 of the present invention. The configuration of the halogen-containing gas processing apparatus of the fourth embodiment is different from that of the third embodiment in that steam is supplied using a steam generator 52 instead of bubbling. Except for this point, the third embodiment is the same as the third embodiment. In the fourth embodiment, the gas temperature controller 51 adjusts the temperature of the mixed gas of the halogen-containing gas and the steam to a predetermined temperature. As a result, an excessive amount of water vapor in the mixed gas flowing in the pipe 28 is cold trapped, and the mixed gas that has passed through the gas temperature controller 51 contains a saturated water vapor amount corresponding to the temperature cooled by the gas temperature controller 51. In. Thus, also in the present embodiment, the amount of water vapor in the mixed gas of the halogen-containing gas and the water vapor can be controlled to a predetermined amount, so that the decomposition of the halogen-containing gas can be performed with high efficiency.

Embodiment 5 FIG. FIG. 9 is a diagram illustrating a configuration of a halogen-containing gas processing apparatus according to Embodiment 5 of the present invention. The configuration of the halogen-containing gas processing apparatus of the fifth embodiment is different from that of the first embodiment in that a ribbon heater 53 is provided as a temperature controller in the pipe 28. Except for this point, the third embodiment is the same as the first embodiment. In the fifth embodiment, the ribbon heater 53 controls the temperature of the pipe 28 to be higher than the temperature of the aqueous medium 23 by 5 ° C. or more, preferably by 10 ° C. or more. Thus, the problem that the amount of water vapor supplied due to condensation in the pipe 28 decreases can be avoided, and the amount of water vapor determined by the temperature of the aqueous medium 23 can be accurately supplied. A decrease in the decomposition efficiency of the compound can be prevented.

Embodiment 6 FIG. FIG. 10 is a diagram illustrating a configuration of a steam supply unit of a halogen-containing gas processing apparatus according to Embodiment 6 of the present invention. The steam supply unit 21 of Embodiments 1 to 5 supplies steam by gas-liquid contact by bubbling, but the steam supply unit 61 of Embodiment 6 uses gas-liquid contact with a dripping aqueous medium. It supplies steam. The configuration other than the steam supply unit is the same as in the first to fifth embodiments.

The steam supply unit 61 of the halogen-containing gas treatment apparatus according to the sixth embodiment includes a container 62 containing an aqueous medium 63.
A pipe 24 for introducing the halogen compound-containing gas discharged from the discharge source into the container 62, a halogen concentration sensor 25 provided on the pipe 24, a pipe 28 for discharging to the discharge processing unit, and an aqueous medium. A temperature controller 64 for controlling the temperature of the aqueous medium 63 to a predetermined temperature based on the halogen concentration; a circulation pump 66 for guiding the temperature-controlled aqueous medium 63 to the upper part of the container 62 through a pipe 65;
Medium dropping section 68 having a number of small holes 67 connected to
And

As in the first embodiment, the halogen compound-containing gas discharged from the discharge source is introduced into the steam supply section 61 through the pipe 24. The halogen concentration contained in the halogen compound is detected by the halogen concentration sensor 25 provided in the pipe 24, and the temperature of the aqueous medium 63 into which the amount of water vapor having the highest decomposition efficiency is mixed is determined based on the detected halogen concentration. The temperature of the aqueous medium 63 is adjusted by the temperature controller 64 so that the temperature of the aqueous medium 63 becomes this temperature. The temperature-controlled aqueous medium 63 is guided to the upper part of the container 62 through a pipe 65 by a circulation pump 66, and is dropped from the aqueous medium dropping section 68 in a shower shape. The halogen compound-containing gas introduced into the container 62 through the pipe 24 is supplied to the aqueous medium 6 in the container 62.
A predetermined amount of water vapor is mixed into the halogen compound-containing gas by coming into gas-liquid contact with the aqueous medium 69 to be dropped in the space above 3. The mixed gas of the halogen compound-containing gas and the water vapor is guided to the discharge processing unit by the pipe 28 in the same manner as in the first embodiment, and is subjected to the same processing. Since the halogen-containing gas treatment apparatus of the sixth embodiment includes the water vapor supply unit 61 as described above, the halogen compound-containing gas does not pass through the aqueous medium, so that the backflow of the aqueous medium can be prevented even when a trouble occurs. , Stable processing is possible.

[0052]

According to the method for treating a halogen-containing gas according to the present invention, a halogen compound-containing gas is mixed with a predetermined amount of water vapor based on the halogen concentration in the gas, and the mixed gas is introduced into a discharge treatment section. Since the halogen compound in the mixed gas is decomposed and the decomposition product is removed, the decomposition efficiency of the halogen compound can be controlled, and the halogen-containing gas can be treated with high efficiency regardless of the halogen concentration in the halogen compound-containing gas. be able to.

Further, the mixing of the halogen compound-containing gas and the predetermined amount of water vapor is performed by gas-liquid contact between the halogen compound-containing gas and the aqueous medium controlled at a predetermined temperature. Mixing control can be performed.

Further, since the gas-liquid contact is performed by discharging the halogen compound-containing gas into the aqueous medium and performing bubbling, the gas-liquid contact between the halogen compound-containing gas and the aqueous medium can be easily performed.

Further, since the gas-liquid contact is performed by contact between the halogen compound-containing gas and the aqueous medium dropped, it is possible to prevent the aqueous medium from flowing backward even when a trouble occurs.

Further, since the water vapor is mixed such that the concentration ratio of water molecules to the halogen atom concentration in the mixed gas becomes 0.25 to 1, the halogen compound can be decomposed with high efficiency.

Also, since a predetermined amount of water vapor is mixed with the halogen compound-containing gas supplied via the vacuum pump, and a rare gas is used as the purge gas for the vacuum pump, the halogen gas is supplied even if a large flow rate of the purge gas is supplied. The decrease in the decomposition efficiency of the compound is small.

Further, since the temperature of the piping through which the mixed gas passes is adjusted to be higher than the temperature of the aqueous medium by 5 ° C. or more, dew condensation on the piping can be prevented, thereby reducing the amount of water vapor in the mixed gas. Can be prevented.

Further, since the temperature of the discharge electrode of the discharge processing section is controlled to be higher than the temperature of the aqueous medium by 5 ° C. or more, dew condensation on the discharge electrode can be prevented, and stable processing can be performed.

Further, after adding an excess of steam to the halogen compound-containing gas in excess of a predetermined amount, the steam added gas is adjusted to a predetermined temperature based on the halogen concentration in the halogen compound-containing gas. The amount of water vapor can be controlled to a predetermined amount.

The halogen-containing gas treatment apparatus according to the present invention comprises a steam supply section for controlling the mixing of a predetermined amount of steam based on the halogen concentration in the halogen compound-containing gas, and a halogen compound-containing gas and a steam supply section. And a discharge processing unit that decomposes the mixed gas with the discharged water vapor by discharge, so that the decomposition efficiency of the halogen compound can be controlled, and the halogen-containing gas can be processed efficiently regardless of the halogen concentration in the halogen compound-containing gas. can do.

Further, the water vapor supply section controls the aqueous medium to a predetermined temperature based on the gas-liquid contact section where the halogen compound-containing gas and the aqueous medium come into gas-liquid contact with each other and the halogen concentration in the halogen compound-containing gas. Since the temperature controller is provided, a predetermined amount of steam can be easily mixed and controlled.

Further, since the gas-liquid contact portion is provided with the bubbling portion for bubbling by discharging the halogen compound-containing gas into the aqueous medium, the gas-liquid contact between the halogen compound-containing gas and the aqueous medium can be easily performed. .

Further, since the gas-liquid contact section has an aqueous medium dropping section for dropping the aqueous medium and a contact section for contacting the halogen compound-containing gas with the aqueous medium dropped from the aqueous medium dropping section, troubles are caused. The backflow of the aqueous medium can be prevented even at the time of occurrence.

Further, since the halogen concentration in the halogen compound-containing gas is detected by the halogen concentration sensor, the halogen concentration can be detected with high accuracy.

Further, since the gas passing through the discharge treatment section is discharged into the aqueous medium and subjected to bubbling, a trapping section for trapping decomposition products generated in the discharge treatment section in the aqueous medium is provided. It is possible to collect the decomposition products of.

Further, since the temperature control section is provided in the pipe connecting the steam supply section and the discharge processing section, the amount of water vapor in the mixed gas introduced into the discharge processing section can be accurately controlled to a predetermined amount. .

Further, since the discharge processing section is provided with a heating source for heating the discharge electrode, it is possible to prevent dew condensation on the discharge electrode and to perform stable processing.

Further, a steam supply unit for mixing steam into the halogen compound-containing gas, and a gas mixture of the halogen-containing gas and the steam mixed by the steam supply unit, which are connected by a pipe to the steam supply unit, are decomposed by electric discharge. Since the discharge processing section and the temperature control section provided at least in part of the pipe and controlling the mixed gas to a predetermined temperature based on the halogen concentration of the halogen-containing gas are provided, the decomposition efficiency of the halogen compound can be controlled, and the halogen compound can be controlled. The halogen-containing gas can be treated with high efficiency regardless of the halogen concentration in the contained gas.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a halogen-containing gas processing apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a result of examining a relationship between a pure water temperature and a CF ₄ decomposition efficiency when pure water is used as an aqueous medium of a steam supply unit in the present invention.

FIG. 3 is a graph showing the result of examining the relationship between the ratio of the saturated water concentration to the CF ₄ concentration and the decomposition efficiency of CF _{4 in} the present invention.

FIG. 4 shows saturated water with respect to F atom concentration in the present invention.
Fraction concentration ratio and CF _FourThe result of examining the relationship between the decomposition efficiency of
FIG.

FIG. 5 is a graph showing the result of examining the relationship between the ratio of the concentration of water molecules to the concentration of halogen atoms and the decomposition efficiency of CF _{4 in} the present invention.

FIG. 6 is a diagram showing an example of a result of examining a relationship between a purge gas flow rate and a halogen compound decomposition efficiency when various purge gases are used.

FIG. 7 is a diagram illustrating a configuration of a halogen-containing gas processing apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a diagram illustrating a configuration of a halogen-containing gas processing apparatus according to Embodiment 4 of the present invention.

FIG. 9 is a diagram illustrating a configuration of a halogen-containing gas processing apparatus according to Embodiment 5 of the present invention.

FIG. 10 is a diagram illustrating a configuration of a steam supply unit of a halogen-containing gas processing apparatus according to Embodiment 6 of the present invention.

FIG. 11 is a diagram illustrating a configuration of a conventional halogen-containing gas processing apparatus.

[Explanation of symbols]

21 steam supply unit, 22 bubbling container, 23 aqueous medium, 24, 28 piping, 25 halogen concentration sensor, 26
Temperature sensor, 27 temperature controller, 31 discharge processing unit,
33, 34 discharge electrode, 35 high voltage power supply, 36 liquid temperature controller, 37 circulation pump, 41 collection unit, 43 aqueous medium, 51 gas temperature controller, 52 steam generator, 53
Ribbon heater, 61 steam supply unit, 68 aqueous medium dropping unit.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masafumi Doi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) in Mitsubishi Electric Corporation 4D002 AA21 AA22 AA24 AC10 BA07 CA01 CA06 CA13 DA05 DA12 DA35 EA02 GA01 GA02 GA03 GB02 GB03 GB08 GB11 GB20 4D020 AA10 BA23 BB03 CB01 CD10 DA03 DB03 DB20 4G075 AA03 AA37 AA42 AA51 AA52 AA53 AA63 BA01 BA05 BB01 BB06 BD05 BD12 BD22 BD27 CA02 CA15 CA57 CA63 DA01 DA13 EA02 EC21

Claims (18)

[Claims] 1. A method according to claim 1, wherein a predetermined amount of water vapor based on a halogen concentration in the gas is mixed with the halogen compound-containing gas, and the mixed gas is introduced into a discharge treatment unit to decompose the halogen compound in the mixed gas. A method for treating a halogen-containing gas, comprising removing the decomposition product. 2. The halogen according to claim 1, wherein the mixing of the halogen compound-containing gas with a predetermined amount of water vapor is performed by gas-liquid contact between the halogen compound-containing gas and an aqueous medium controlled at a predetermined temperature. Gas containing method. 3. The method for treating a halogen-containing gas according to claim 2, wherein the gas-liquid contact is performed by discharging the halogen compound-containing gas into an aqueous medium and performing bubbling. 4. The method for treating a halogen-containing gas according to claim 2, wherein the gas-liquid contact is performed by contacting the halogen compound-containing gas with a dropping aqueous medium. 5. The halogen-containing gas treatment method according to claim 1, wherein the water vapor is mixed such that a concentration ratio of water molecules to a halogen atom concentration in the mixed gas becomes 0.25 to 1. 6. The method according to claim 1, wherein said predetermined amount of steam is mixed with said halogen compound-containing gas supplied via a vacuum pump, and a rare gas is used as a purge gas of said vacuum pump. The method for treating a halogen-containing gas described in the above. 7. The mixed gas is introduced into a discharge treatment section through a pipe, and the temperature of the pipe is set to 5 ° C. below the temperature of the aqueous medium.
The method for treating a halogen-containing gas according to any one of claims 2 to 6, wherein the temperature is adjusted to be higher. 8. The method for treating a halogen-containing gas according to claim 2, wherein an electrode temperature of the discharge treatment section is adjusted to be 5 ° C. or more higher than a temperature of the aqueous medium. 9. A method of mixing a halogen compound-containing gas with a predetermined amount of water vapor, after adding an excess of water vapor to the halogen compound-containing gas in excess of the predetermined amount. 2. The method for treating a halogen-containing gas according to claim 1, wherein the method is performed by adjusting the temperature to a predetermined temperature based on the concentration. 10. A steam supply unit for controlling mixing of a predetermined amount of water vapor based on the halogen concentration in the halogen compound-containing gas, and mixing of the halogen compound-containing gas with water vapor mixed by the water vapor supply unit. A halogen-containing gas processing apparatus comprising: a discharge processing unit configured to decompose a gas by discharge. 11. A water vapor supply unit controls a temperature of the aqueous medium to a predetermined temperature based on a gas-liquid contacting part in which the halogen compound-containing gas and the aqueous medium come into gas-liquid contact with each other and a halogen concentration in the halogen compound-containing gas. The halogen-containing gas processing apparatus according to claim 10, further comprising: a temperature control unit. 12. The halogen-containing gas treatment apparatus according to claim 11, wherein the gas-liquid contact unit includes a bubbling unit that performs bubbling by discharging the halogen compound-containing gas into the aqueous medium. 13. The gas-liquid contact section includes an aqueous medium dropping section for dropping an aqueous medium, and a contact section for contacting the halogen compound-containing gas with the aqueous medium dropped from the aqueous medium dropping section. 12. The halogen-containing gas treatment apparatus according to 11. 14. The method according to claim 10, wherein the halogen concentration in the halogen compound-containing gas is detected by a halogen concentration sensor.
The halogen-containing gas treatment apparatus according to any one of claims 13 to 13. 15. A collecting unit for capturing a decomposition product generated in the discharge processing unit in the aqueous medium by discharging the gas that has passed through the discharge processing unit into the aqueous medium and performing bubbling. 15. The halogen-containing gas treatment apparatus according to any one of 10 to 14. 16. The halogen-containing gas processing apparatus according to claim 10, further comprising a temperature control section provided in a pipe connecting the steam supply section and the discharge processing section. 17. The halogen-containing gas processing apparatus according to claim 10, wherein the discharge processing unit includes a heating source that heats the discharge electrode. 18. A steam supply unit for mixing steam into a halogen compound-containing gas, and a mixed gas of the halogen compound-containing gas and steam mixed by the steam supply unit, which is connected by a pipe to the steam supply unit. A halogen-containing gas processing apparatus, comprising: a discharge processing unit that is decomposed by a gas;