Development of Harmless Disposal System of Fluoride and Chloride Gases by Chemical Reaction with Metal Oxide

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A new technology to make fluoride and chloride gases such as NF_3 CF_4 and BC1_3 harmless has been developed and a new concept on the removing of toxic gas to be used in the advanced process of materials has been established. The fluoride gases are toxic and special type of gases to be used in the process of manufacturing semiconductors and their specific applications include the dry etching of semiconductors, cleaning of CVD systems, the oxidation agent for rocket fuel etc. As a fluoride gas like NF3 is, however, toxic and highly chemically stable, if discharged into the atmosphere, it is liable to cause far-reaching adverse influences on global warning in the same manner as carbon dioxide gas and freon gas.The research team utilized the chemical reaction between fluoride gas and a metal chlorides and oxides, and established a new technology to make fluoride gas contained in the exhaust gas from semiconductor manufacturing plants convert directly into a harmless substance. Experimental results verify that the chemical reactions can be take place at substantially lower temperature of 80-400℃ as compared with the combustion treatment method. The other favorable characteristics are that continuous treatment is possible at a low temperature under atmospheric pressure, and that the process is compact easily controllable and safely operable at low running cost.