KR20030085596A - Method for treating exhaust gas - Google Patents

Abstract

The present invention is an exhaust gas treatment method comprising combusting an exhaust gas containing a fluorine gas or a halogen fluoride gas discharged from an etching process or a cleaning process in a combustion chamber in which a fluoride passivation film is formed on a surface thereof. The method can be used to treat exhaust gases emitted from semiconductor manufacturing processes that contain fluorine gas or halogen fluoride gas in high concentrations or in large quantities, which is safe, energy saving and more efficient. Do.

Description

Exhaust gas treatment method {METHOD FOR TREATING EXHAUST GAS}

The exhaust gas discharged from the various processes of manufacturing a semiconductor contains gases, such as a semiconductor material gas, an etching gas, and a cleaning gas, and this gas may be harmful. They sometimes contain gases that adversely affect the environment, and exhaust gases containing these components cannot be directly emitted to the atmosphere.

The method for treating the exhaust gas is conventionally

(1) a wet decontamination method in which an oxidation reaction or a neutralization reaction is carried out using a neutralizing agent such as caustic soda (sodium hydroxide);

(2) reaction decomposition method by the catalyst layer,

(3) a dry decontamination method by adsorption to an oxide or the like,

(4) pyrolysis method of incorporating an electric heater,

(5) combustion elimination method,

These methods are widely known, and these methods are utilized according to desired characteristics.

In recent years, not only the harmful components contained in the exhaust gas discharged from the semiconductor manufacturing process are diversified, but also the size of wafers and liquid crystal panels is remarkably increased, and the corresponding manufacturing apparatus is also enlarged. The amount is greatly increasing. In addition, due to the multi-chambers associated with the spread of sheetfed devices and the complexity of manufacturing processes, a large amount of exhaust gas discharged from different paths can be simultaneously processed or the time cycles can be changed in the same path. There is a case where it is necessary to safely treat the exhaust gas having characteristics using the same decontamination apparatus. Therefore, in recent years, as a decontamination method of combustible fuel gas or the like at high temperature, the toxic components and exhaust gas components harmful to the environment are converted into harmless substances or converted into substances that can be easily processed. Heat treatment type decontamination methods, such as an anticorrosion system or a pyrolysis system, are examined.

However, especially in the combustion elimination method, since the exhaust gas discharged from the semiconductor manufacturing process is burned at a high temperature together with fuel gas such as city gas, LPG and methane, and supporting gas such as air or oxygen, the exhaust gas is exhaust gas. There is a problem in that NO _x is generated as a by-product due to the nitrogen element content contained in the air or nitrogen in the air.

The NO _x gas contained in the exhaust gas after combustion is often produced at very high concentrations of 1 to 30%, depending on the apparatus used and the combustion conditions, and is limited to a concentration of TLV (NO 25 ppm, NO ₂ 3 ppm). The method is being reviewed. For example, Japanese Laid-Open Patent Publication No. 2001-1939 1 describes various studies on the shape of a combustion chamber, a nozzle, and the like in order to reduce the amount of NO _x produced. However, in the case of burning the exhaust gas containing the NF ₃ gas that is used in large quantities for the etching and cleaning processes, the amount of NO _x generated may increase, and therefore improvement is desired.

On the other hand, in the semiconductor manufacturing process, cleaning is attempted using a fluorine gas, a halogen fluoride gas, or a mixed gas thereof as a higher performance cleaning gas. For example, J. APPL. Phys., P2939 56 (10) No. In 15, 1984, a study is reported that the cleaning performance of fluorine gas and halogen fluoride gas is superior to cleaning using NF ₃ gas.

However, fluorine gas or halogen fluoride gas is a very active, strong oxidizing agent, and because of its excellent chemical reactivity, it may react with an oxidizing substance at room temperature and ignite, and also has high corrosiveness to the device material. Therefore, device materials need to be carefully selected from specific high corrosion resistant metals, and in addition to free from oils and water, tetrafluoroethylene resins widely used in semiconductor manufacturing apparatuses as high corrosion resistance resins are also used. Sometimes it is considered unsuitable for given conditions of use.

As a decontamination apparatus for halogen fluoride gas such as fluorine gas or chlorine trifluoride, a wet absorbing device which neutralizes and absorbs by scrubber using an aqueous alkali solution such as caustic soda or caustic potassium, or a solid adsorbent such as activated alumina or soda lime Dry decontamination apparatus which adsorbs and removes is used. However, all these methods have the disadvantage that they cannot handle exhaust gases containing high concentrations of fluorine gas or halogen fluoride gas. In addition, when the amount of fluorine gas or halogen fluoride gas used increases, when a wet decontamination device such as an alkali scrubber is used, problems such as an increase in the size of the absorption tower, the trouble of the wastewater treatment of the absorbent liquid, and an increase in the operating cost become problems. . In the dry decomposition decontamination apparatus or the adsorption removal decontamination apparatus, not only is it difficult to form a large flow decontamination apparatus, but also the operation costs are greatly increased due to the increase in the exchange frequency of the solid decomposition agent and the adsorbent and the like. It is easy to cause trouble in safety management.

The present invention relates to a method and a treatment apparatus for the exhaust gas. More specifically, the present invention relates to a method and apparatus for treating exhaust gas containing fluorine gas or halogen fluoride gas discharged from an etching process or a cleaning process in a semiconductor manufacturing process, and a semiconductor device using the method and apparatus. It relates to a manufacturing method.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the processing apparatus for performing the waste gas processing method of this invention.

In this figure, 1 is a process exhaust gas, 2 is a diluent gas, 3 is a supporting gas, 4 is combustible gas for combustion, 5 is air, 6 is air emission gas, 7 is combustion chamber, 8 is combustion chamber, 9 is combustion The gas cooling device, 10 is an alkali scrubber, and 11 is an exhaust blower.

In view of this background, it is an object of the present invention to treat exhaust gases emitted from semiconductor manufacturing processes containing high concentrations or large amounts of fluorine gas or halogen fluoride gas, which is safe, energy efficient and more efficient than decontamination. It is to provide a decontamination method and apparatus capable of doing so.

As described above, when a fluorine gas or a halogen fluoride gas is used in the semiconductor manufacturing process, the exhaust gas is treated by a dedicated decontamination apparatus alone, but the semiconductor device is enlarged by using the method of the present invention. The above problems can be solved by multiplying, increasing complexity, and reducing the installation space of the removing device.

The present inventors have diligently studied to solve the above problems, and as a result, a combustion chamber in which a fluoride gas or a halogen fluoride gas containing a fluorine gas or a halogen fluoride gas is discharged from an etching process or a cleaning process is formed on a surface thereof. It was found that the above problems can be solved by introducing into a combustion apparatus equipped with a combustion chamber and using the treatment method of burning the exhaust gas, thereby completing the present invention.

That is, the present invention provides an exhaust gas treatment method comprising combusting an exhaust gas containing a fluorine gas or a halogen fluoride gas discharged from an etching process or a cleaning process in a combustion chamber in which a fluoride passivation film is formed on a surface thereof.

It is preferable that the said fluoride passivation film consists of nickel fluoride.

The concentration of fluorine gas or halogen fluoride gas is preferably 5 mmol% or less.

It is preferable that the content of nitrogen oxide contained in exhaust gas after combustion is less than 5 Pa ppm.

The present invention also provides an exhaust gas treating apparatus having an exhaust gas inlet, a fuel inlet, a combustion chamber, a combustion chamber, an air inlet, and an exhaust pipe, wherein a fluoride passivation film is formed on at least the surface of the combustion chamber.

The combustion chamber is formed of at least one material selected from nickel, high nickel containing alloy and monel, and a fluoride passivation film is preferably formed on the surface of the material.

The combustion chamber is formed by one or more kinds of materials selected from stainless steel and steel, and is composed of a thin film or alumina or aluminum nitride composed of nickel, nickel alloy electroplating, electroforming plating, nickel alloy electroless plating on the surface of the material. It is preferable to have a ceramic thin film, and a fluoride passivation film is formed on the surface of the thin film.

The present invention also includes an etching process or a cleaning process using fluorine gas or a halogen fluoride gas as an etching gas or cleaning gas, and a decontamination process for combusting a gas containing fluorine gas or halogen fluoride gas discharged from such process. A method for manufacturing a semiconductor device, the method of manufacturing a semiconductor device wherein the above-mentioned decontamination process is performed in a combustion chamber in which a fluoride passivation film is formed on the surface thereof.

The fluoride passivation film is preferably composed of nickel fluoride.

Hereinafter, preferred embodiments of the present invention will be described in detail.

In the method for treating exhaust gas of the present invention, exhaust gas containing fluorine gas or halogen fluoride gas discharged from an etching process or a cleaning process is burned in a combustion chamber in which a fluoride passivation film is formed on the surface thereof. That is, the present invention detoxifies the exhaust gas discharged from the semiconductor manufacturing process including not only a fluorine gas or a halogen fluoride gas but also a gas such as SiH ₄ or the like used as a film-forming gas at a predetermined temperature. Processing.

The treatment method of the present invention can be sufficiently harmlessly treated under the conditions of reducing the amount of fuel supplied and lowering the combustion temperature, compared to normal combustion conditions that do not contain fluorine gas or halogen fluoride gas. It is possible to process on a compound which is easy to operate, and by operating under such suitable conditions, the amount of carbon dioxide and NO _x which are decomposition by-products emitted from the decontamination apparatus can be significantly reduced.

According to the invention, SiH ₄ , SiH ₂ Cl ₂ , NH ₃ , PH ₃ , WF ₆ , Si (OC ₂ H ₅ ) ₄ , which are commonly used for the process of manufacturing a semiconductor using a combustion-type decontamination apparatus Decontamination treatment of fluorine gas and halogen fluoride gas simultaneously with other gaseous components emitted from film-forming gas such as NF ₃ , H ₂ , B ₂ H ₆ , CH ₄ , C ₂ H ₂ , cleaning gas or semiconductor manufacturing process do. In this case, only the fluorine gas or the halogen fluoride gas may be a component to be treated in the exhaust gas. The concentration of fluorine gas or halogen fluoride gas contained in the exhaust gas is preferably 5% by mol or less.

The operating method of the combustion elimination apparatus of the present invention is compared with the combustion conditions (for example, the combustion conditions necessary for decomposing trifluoride nitrogen gas) in which the introduced exhaust gas does not contain fluorine gas or halogen fluoride gas. Even in the operating conditions in which the fuel supply amount is lowered by 10 to 30% and the combustion temperature is lowered by 50 ° C or more, the toxic gas component can be made harmless and converted into a substance that can be easily decomposed and removed. Therefore, by using the treatment method of the present invention, it is possible to reduce the proportion of the amount of fuel gas using carbon dioxide, which is a decomposition byproduct discharged from the decontamination apparatus. In addition, the amount of NO _x produced can be significantly reduced by lowering the combustion temperature, and it is also possible to achieve the amount of NO _x produced below 5 ppm by ppm.

It is obvious that the operation of lowering the combustion temperature greatly contributes to safety aspects in terms of operation management, and since the material surface temperature of the apparatus in the area where the exhaust gas is burned or in its entire chamber part is lowered, the degree of corrosion of the device material is remarkable. Is reduced. Therefore, the maintenance frequency of the device can be reduced, and it is obvious that it is a cost benefit in consideration of the long life of the device.

The burned exhaust gas is finally decomposed to a hydrolysis facility such as an alkaline scrubber connected to an exhaust pipe of a combustion decontamination tower, such as hydrogen halide such as hydrogen fluoride, NO _x or other decomposition such as silicon tetrafluoride. The material is absorbed.

An exhaust gas treatment apparatus of the present invention includes an exhaust gas inlet, a fuel inlet, a combustion chamber, a combustion chamber, an air inlet, and an exhaust pipe, and at least a fluoride passivation film is formed on the surface of the combustion chamber.

Fig. 1 shows an example of a treatment apparatus capable of carrying out the treatment method of the exhaust gas of the present invention. The mixed winding gas containing fluorine gas or halogen fluoride gas is passed through a flame wall to provide a spiral winding of the supporting gas ( It is an example of the apparatus which introduce | transduces into a vortex stream and uses the system of a combustion decomposition process.

The material of the device of FIG. 1 requires a high corrosion resistance material to withstand the flow of fluorine gas or halogen fluoride gas. It is preferable that the combustion chamber 8 is formed by nickel or a high nickel containing alloy or monel by becoming high temperature by the heat of combustion, and the fluoride passivation film was formed in the surface. In another preferred embodiment, the combustion chamber 8 is formed of ordinary stainless steel or ordinary steel, and has a surface formed of nickel, nickel alloy electroplating, electroforming plating, or nickel alloy electroless plating, spray coating, or the like. It is preferable to have a ceramic thin film composed of alumina or aluminum nitride having excellent fluorine gas resistance and heat resistance, and a fluoride passivation film formed on the surface of the thin film. In the case of nickel plating, an electroless plating treatment of nickel boron system is preferred in order to achieve excellent heat resistance. In the same manner as in the combustion chamber 7, a fluoride passivation film is preferably formed on the surface thereof.

It is preferable that the device component is subjected to passivation treatment in fluorine gas in advance. In particular, the surrounding part of the site where the exhaust gas has been burned is exposed to considerably high temperatures by radiant heat and heat transmission from the burned site. Therefore, it is preferable to manufacture the material of this site | part from nickel, a high nickel containing alloy, or a monel. Conventional stainless or steel materials can be subjected to corrosion treatment such as nickel electroplating, electroforming plating, nickel electroless plating. It is also preferable that the device member be subjected to passivation treatment in fluorine gas in advance in the same manner.

It can be carried out using a known method that has undergone passivation treatment in fluorine gas, and for example, the method described in Japanese Laid-Open Patent Publication No. 11-92912 can be used. Specifically, for example, the nickel surface used as the device component may be forcibly oxidized first, and then the oxide film may be reacted with fluorine gas to form a fluoride passivation film. Even in the case of using an apparatus component in which a nickel thin film is formed on the surface of stainless steel, the fluoride passivation film can be formed on the surface by performing oxidation and fluorination treatment in the same manner.

As described above, according to the present invention, an exhaust gas containing fluorine gas or halogen fluoride gas discharged from an etching process or a cleaning process is introduced into a combustion apparatus having a combustion chamber in which a fluoride passivation film is formed on the surface thereof, and By combusting the exhaust gas, the exhaust gas treatment can be efficiently performed.

The present invention includes a semiconductor process comprising an etching process or a cleaning process using a fluorine gas or a halogen fluoride gas as an etching gas or a cleaning gas, and a decontamination process of burning a gas containing the fluorine gas or halogen fluoride gas discharged from such a process. As a manufacturing method of a device, the manufacturing method of the semiconductor device which further performs the said removal process in the combustion chamber in which the fluoride passivation film was formed in the surface is further provided.

Although an Example and a comparative example are given to this invention further in detail below, this invention is not limited to these Examples.

Example 1

Nickel plating and fluorine passivation treatment were performed on the stainless steel combustion chamber of the combustion type decontamination apparatus and its surroundings, and a combustion decontamination experiment using fluorine gas was conducted. The operating conditions and fluorine introduction conditions of the combustion decontamination apparatus are shown in Table 1, and the composition analysis results of the exhaust gas discharged after combustion and decontamination are shown in Table 2. The combustion chamber temperature was measured by a thermocouple attached to the outer wall of the combustion chamber. The concentrations of nitrogen monoxide and nitrogen dioxide contained in the exhaust gas after combustion were measured by a gas detector tube, and the concentration of the hydrogen fluoride gas was measured by infrared spectroscopy. Nitrogen trifluoride was measured using a detector. Sampling was performed with aqueous potassium iodide solution, the fluorine gas concentration was measured by titration with a sodium thiosulfate solution of the sample solution, and the metal concentration of the sample solution was measured by inductively coupled plasma emission spectrometry.

Fuel methane flow rate Combustion Aid Air Flow Cooling air exhaust Fluorine flow rate Dilute nitrogen flow rate Combustion chamber temperature (L / min) (L / min) (m ³ / min) (L / min) (L / min) (℃) 25 30 30 13.5 240 305-315

Hydrogen Floride Gas Calculated Concentration Hydrogen fluoride gas measurement concentration Fluorine measurement concentration Nitric oxide concentration Nitrogen Dioxide Measurement Concentration Other combustion reaction products (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) 900 900 <10 <0.1 <0.1 Not detected

As shown in Table 2, nitrogen monoxide and nitrogen dioxide were not contained in the exhaust gas after combustion at all, and the total amount of fluorine introduced into the combustion decontamination apparatus reacted and was converted into hydrogen fluoride gas. It was confirmed by infrared spectroscopy and inductively coupled plasma emission spectrometry of the sample liquid that the combustion exhaust gas contained no combustion reaction products other than hydrogen fluoride gas, water vapor and carbon dioxide.

Comparative Example 1

Nitrogen trifluoride was used in place of the fluorine gas, and a combustion elimination experiment was conducted in which the flow rate of the nitrogen trifluoride was 9. 0 L / min. The operating conditions of the combustion elimination device and the introduction conditions of the nitrogen fluoride are shown in Table 3, and the analysis results of the combustion exhaust gas are shown in Table 4.

Fuel methane flow rate Combustion Aid Air Flow Cooling air exhaust Nitrogen Triple Ride Flow Dilute nitrogen flow rate Combustion chamber temperature (L / min) (L / min) (m ³ / min) (L / min) (L / min) (℃) 30 311 30 9.0 240 350-360

Hydrogen Floride Gas Calculated Concentration Hydrogen fluoride gas measurement concentration Nitrogen Triplelide Measurement Concentration Nitric oxide concentration Nitrogen Dioxide Measurement Concentration Other combustion reaction products (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) 900 900 <1 72 12 Not detected

The operating conditions shown in Table 3 represent combustion operating conditions in which no nitrogen trifluoride gas is detected in the exhaust gas. Thus, the total amount of nitrogen trifluoride introduced into the combustion decontamination apparatus reacts and converts into hydrogen fluoride gas, but both nitrogen monoxide and nitrogen dioxide are generated in the exhaust gas, and greatly exceed the allowable concentration.

Comparative Example 2

Compared to Example 1, the same combustion decontamination experiment as in Example 1 was conducted except that the fuel methane flow rate was increased to 30 L / min and the combustion chamber temperature was increased to 350 ° C or higher. The operating conditions and fluorine introduction conditions of the combustion elimination device are shown in Table 5, and the results of the composition analysis of the combustion exhaust gas are shown in Table 6.

Fuel methane flow rate Combustion Aid Air Flow Cooling air exhaust Fluorine flow rate Dilute nitrogen flow rate Combustion chamber temperature (L / min) (L / min) (m ³ / min) (L / min) (L / min) (℃) 30 341 30 13.5 240 360-370

Hydrogen Floride Gas Calculated Concentration Hydrogen fluoride gas measurement concentration Fluorine measurement concentration Nitric oxide concentration Nitrogen Dioxide Measurement Concentration Other combustion reaction products (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) 900 850 <10 0.5 1.0 Not detected

As shown in Table 6, part of the fluorine introduced into the combustion elimination apparatus was consumed by reacting with the combustion chamber and its member surface without being discharged as hydrogen fluoride. Part of it was confirmed that metal fluoride was formed as fine powder. The results of the exhaust gas analysis also confirmed the formation of nitrogen monoxide and nitrogen dioxide.

Comparative Example 3

The same combustion decontamination experiment as in Example 1 was conducted except that stainless steel (SUS304 material) was used without coating the combustion chamber. The operating conditions and the fluorine introduction conditions of the combustion elimination device are shown in Table 7, and the composition analysis results of the combustion exhaust gas are shown in Table 8.

Fuel methane flow rate Combustion Aid Air Flow Cooling air exhaust Fluorine flow rate Dilute nitrogen flow rate Combustion chamber temperature (L / min) (L / min) (m ³ / min) (L / min) (L / min) (℃) 25 308 30 13.5 240 310-320

Hydrogen Floride Gas Calculated Concentration Hydrogen fluoride gas measurement concentration Fluorine measurement concentration Nitric oxide concentration Nitrogen Dioxide Measurement Concentration Other combustion reaction products (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) 900 700 <10 <0.1 <0.1 Chromium compound

As shown in Table 8, no significant proportion of fluorine introduced into the combustion decontamination apparatus was identified as hydrogen fluoride, and no gaseous components such as fluoride chromium were produced.

Comparative Example 4

The coating of the combustion chamber was made of nickel plating only, and the same combustion control experiment as in the above example was conducted except that no fluorine treatment was performed. The operating conditions of the combustion elimination device and the introduction conditions of fluorine are shown in Table 9, and the composition analysis results of the combustion exhaust gas are shown in Table 10.

Fuel methane flow rate Combustion Aid Air Flow Cooling air exhaust Fluorine flow rate Dilute nitrogen flow rate Combustion chamber temperature (L / min) (L / min) (m ³ / min) (L / min) (L / min) (℃) 25 299 30 13.5 240 310-320

Hydrogen Floride Gas Calculated Concentration Hydrogen fluoride gas measurement concentration Fluorine measurement concentration Nitric oxide concentration Nitrogen Dioxide Measurement Concentration Other combustion reaction products (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) 900 820 <10 <0.1 <0.1 Not detected

As shown in Table 10, the fluorine gas introduced into the combustion decontamination apparatus was consumed slightly by reacting with the combustion apparatus material surface.

Comparative Example 5

The combustion elimination experiment was carried out in the same manner as in Example 1 except that the introduction gas was used as the nitrogen trifluoride, and the flow rate of the nitrogen trifluoride was set to 9. 0 L / min. However, only stainless steel (SUS304) was used without surface treatment of the combustion chamber. The operating conditions of the combustion elimination device and the introduction conditions of nitrogen trifluoride nitrogen are shown in Table 11, and the composition analysis results of the combustion exhaust gas are shown in Table 12.

Fuel methane flow rate Combustion Aid Air Flow Cooling air exhaust Nitrogen Triple Ride Flow Dilute nitrogen flow rate Combustion chamber temperature (L / min) (L / min) (m ³ / min) (L / min) (L / min) (℃) 30 305 30 9.0 240 350-360

Hydrogen Floride Gas Calculated Concentration Hydrogen fluoride gas measurement concentration Nitrogen Triplelide Measurement Concentration Nitric oxide concentration Nitrogen Dioxide Measurement Concentration Other combustion reaction products (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) (vol-ppm) 900 860 <1 70 11 Not detected

As shown in Table 12, the nitrogen trifluoride introduced into the combustion decontamination unit was reacted and converted to fluoride hydrogen gas, but part of it was lost by reaction with the device material, while both nitrogen monoxide and nitrogen dioxide Produced significantly exceeded the allowable concentration.

After the operation of combustion and decontamination, metal surface analysis was performed on the inner surfaces of the combustion chambers of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5. The measurement was performed with an energy dispersive X-ray analyzer.

Metal detected (mass%) Ni Fe Cr Etc Example 1 100 0 0 0 Comparative Example 1 100 0 0 0 Comparative Example 2 100 0 0 0 Comparative Example 3 7.7 75.8 16.5 0 Comparative Example 4 100 0 0 0 Comparative Example 5 7.5 73.5 19 0 Note SUS316L 12 69.5 16 Mo 2.5 Note SUS304 8 74 18 0

The combustion chamber, surface-treated with nickel, showed no significant damage and exhibited high corrosion resistance against fluorine gas and nitrogen trifluoride.

Next, the metal surface analysis was performed about the inner surface of the combustion chamber after the combustion removal of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5. The measurement was performed with an energy dispersive X-ray analyzer.

Metal detected (mass%) Ni Fe Cr Etc Example 1 100 0 0 0 Comparative Example 1 100 0 0 0 Comparative Example 2 100 0 0 0 Comparative Example 3 7.9 88.1 7.9 0 Comparative Example 4 100 0 0 0 Comparative Example 5 9.6 75.8 14.7 0 Note SUS316L 12 69.5 16 Mo 2.5 Note SUS304 8 74 18 0

Comparative Example 3 confirmed that there was a significant loss of Cr from the material. In the case of Comparative Example 5, Cr concentration was slightly decreased. The microscopic observation also showed cracks, and not only the formation and evaporation of the Cr fluoride, but also the peeling of the fluoride-forming film such as the formation of a higher order fluoride from trivalent Fe 2 valent in the stainless material.

As for the damaged state of the stainless steel of a combustion chamber and a combustion chamber, when the fluorine gas and the nitrogen trifluoride were compared, all the Cr concentration changes of the comparative example 3 which burned fluorine gas were large, and the appearance was remarkably damaged.

In the case of the combustion chamber and the stainless steel in the combustion chamber, compared to the combustion chamber, both the fluorine gas and the nitrogen trifluoride in the combustion chamber were larger in the Cr concentration than in the combustion chamber. This is considered to be because the oxidation reaction by the oxidizing salt predominates in the combustion chamber, particularly in the part of the wall thereof.

As described above, by using the treatment method of the present invention, when the fluorine gas or the halogen fluoride gas is discharged in a high concentration or in a large amount, or the gases of different properties, including these, the same decontamination apparatus can be treated at the same time. There is a number. The method of the present invention is preferably used in a semiconductor manufacturing process, is an efficient and economical decontamination treatment method that fully considers safety measures, and conserves the global environment, and has high industrial utility.

Claims (11)

A method for treating exhaust gas, comprising: burning exhaust gas containing fluorine gas or halogen fluoride gas discharged from an etching process or a cleaning process in a combustion chamber having a fluoride passivation film formed on its surface. The method of claim 1, wherein said fluoride passivation film is comprised of nickel fluoride. The method according to claim 1 or 2, wherein the concentration of the fluorine gas or the halogen fluoride gas is 5 mmol% or less. The method according to any one of claims 1 to 3, wherein the content of nitrogen oxide contained in the exhaust gas after combustion is less than 5 ppmolppm. An exhaust gas inlet, a fuel inlet, a combustion chamber, a combustion chamber, an air inlet, and an exhaust pipe, and a fluoride passivation film formed on at least the surface of the combustion chamber. 6. An apparatus according to claim 5, wherein the combustion chamber is formed of at least one material selected from nickel, high nickel containing alloy and monel, and a fluoride passivation film is formed on the surface of the material. 6. A thin film or alumina according to claim 5, wherein the combustion chamber is formed of at least one material selected from stainless steel and steel, and the surface of the material is made of nickel, nickel alloy electroplating, electroforming plating or nickel alloy electroless plating. An apparatus having a ceramic thin film composed of aluminum nitride, wherein a fluoride passivation film is formed on a surface of the thin film. Fabrication of a semiconductor device comprising an etching process or a cleaning process using a fluorine gas or a halogen fluoride gas as an etching gas or a cleaning gas and a decontamination process of burning a gas containing the fluorine gas or the halogen fluoride gas discharged from such a process A method for manufacturing a semiconductor device, wherein the decontamination process is performed in a combustion chamber in which a fluoride passivation film is formed on a surface. 9. The method of claim 8, wherein said fluoride passivation film is comprised of nickel fluoride. 9. The method of claim 8, wherein the combustion chamber is formed of at least one material selected from nickel, high nickel containing alloys and monels, and a fluoride passivation film is formed on the surface of the material. 9. The thin film or alumina of claim 8, wherein the combustion chamber is formed of at least one material selected from stainless steel and steel, and the surface of the material is made of nickel, nickel alloy electroplating, electroforming plating or nickel alloy electroless plating. A ceramic thin film composed of aluminum nitride, wherein the fluoride passivation film is formed on the surface of the thin film.