Method for treating exhaust gas

Abstract

Exhaust gas containing fluorine gas or halogen fluoride gas emitted from etching or cleaning steps is burned in a combustion chamber having a fluoride passivation film formed on its surface. It is possible to treat exhaust gas emitted from semiconductor fabrication processes which contains fluorine gas or halogen fluoride gas in high concentrations or large volumes, while abatement treatment can be accomplished safely and efficiently with less energy usage.

1 . An exhaust gas treatment process which comprises burning exhaust gas containing fluorine gas or halogen fluoride gases emitted from etching or cleaning steps in a combustion chamber having a fluoride passivation film formed on its surface.  
   
   
       2 . The process as claimed in  claim 1 , wherein the fluoride passivation film is composed of nickel fluoride.  
   
   
       3 . The process as claimed in  claim 1  or  2 , wherein the concentration of fluorine gas or halogen fluoride gases is no greater than 5 vol %.  
   
   
       4 . The process as claimed in  claim 1  or  2 , wherein the content of nitrogen oxides in the exhaust gas after combustion is less than 5 volppm.  
   
   
       5 . An exhaust gas treatment system equipped with an exhaust gas introduction port, a fuel introduction port, a precombustion chamber, a combustion chamber, an air introduction port and an exhaust duct, and having a fluoride passivation film formed on at least the surface of the combustion chamber.  
   
   
       6 . The system as claimed in  claim 5 , wherein the combustion chamber is formed of at least one type of material selected from the group consisting of nickel, nickel-rich alloys and Monel metal, and a fluoride passivation film is formed on the surface of the material.  
   
   
       7 . The system as claimed in  claim 5 , wherein the combustion chamber is formed of at least one type of material selected from the group consisting of stainless steel and steel materials, with the surface of the material having a thin-film composed of nickel, nickel alloy electroplating, electrocast plating or nickel alloy electroless plating or a ceramic thin-film composed of alumina or aluminum nitride, and a fluoride passivation film, formed over the surface of the thin-film.  
   
   
       8 . A semiconductor device fabrication process comprising an etching or cleaning step employing fluorine gas or halogen fluoride gas as the etching gas or cleaning gas and an abatement step wherein the gas containing fluorine gas or halogen fluoride gases emitted from the previous step is burned, the abatement step being carried out in a combustion chamber having a fluoride passivation film formed on its surface.  
   
   
       9 . The process as claimed in  claim 8 , wherein the fluoride passivation film is composed of nickel fluoride.  
   
   
       10 . The process of  claim 8 , wherein the combustion chamber is formed of at least one type of material selected from the group consisting of nickel, nickel-rich alloys and Monel metal, and a fluoride passivation film is formed on the surface of the material.  
   
   
       11 . The process as claimed in  claim 8 , wherein the combustion chamber is formed of at least one type of material selected from the group consisting of stainless steel and steel materials, with the surface of the material having a thin-film composed of nickel, nickel alloy electroplating, electrocast plating or nickel alloy electroless plating or a ceramic thin-film composed of alumina or aluminum nitride, and a fluoride passivation film formed over the surface of the thin-film.  
   
   
       12 . The process as claimed in  claim 3 , wherein the content of nitrogen oxides in the exhaust gas after combustion is less than 5 volppm.