| 摘要 |
PURPOSE:To purify NF3 contg. N2F2 or N2F2 plus N2O as impurities by removing impurities by one step without requiring troublesome procedures with continuous operation being realized for a long period by allowing NF3 contg. the impurities to contact with active carbon. CONSTITUTION:NF3 contg. N2F2 or N2F2 puls N2O is allowed to contact with active carbon. Impurities are removed by one step at room temp. continuously for a long period without requiring troublesome procedures. Any kind of active carbon, such as coconut shell active carbon, or that derived from petroleum or coal, etc., is useful. Crude NF3 and relatively low purity NF3 prepd. by the conventional process are both purified by this method. When NF3 is used as cleaning gas of a CVD device, both waste gas can be treated by this process to purify the contaminated NF3 thus permitting reutilization. Effective utilization of expensive NF3 has become possible.
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