Exhaust-gas plasma detoxification method, and device for same

Abstract

Provided is a plasma detoxification method in which all of exhaust gas charged into a thermolysis column is necessarily passed through a high-temperature region formed by a plasma jet and reliably decomposed. In a method for concentrating a plurality of plasma jets (P) toward a point (Q), the respective plasma jets (P) are generated from a plurality of plasma jet torches (2a, 2b, (2c)) installed facing toward a reaction space (D) of exhaust gas (H), the plasma jets (P) jetting toward the given point (Q) within the reaction space (D), and the exhaust gas (H) is supplied toward the point (Q) from between the plurality of plasma jet torches (2a, 2b, (2c)).

Description

technical field [0001] The present invention relates to the improvement of plasma detoxification method and plasma detoxification device in the thermal decomposition process of waste gas discharged from semiconductor manufacturing process. Background technique [0002] Gases of various compounds are used in the manufacturing process of electronic devices such as semiconductors and liquid crystals, such as CF 4 and C 2 f 6 Such perfluorocarbons, NF 3 Such perfluorinated compounds (hereinafter, referred to as "PFC") such as fluorine compounds not containing carbon are used as cleaning gases for the CVD chamber. In addition, in this specification, the waste gas containing a perfluorinated compound is called a perfluorinated compound waste gas or a PFC waste gas. [0003] Among them, with CF 4 or C 2 f 6 Typical perfluorocarbons are nonflammable and the compounds themselves are stable, so they remain unchanged for a long period of time when they are released into the atmo...

AI Technical Summary

Problems solved by technology

For the lifetime until consumed in the atmosphere, the CF 4 In the case of 50000, in C 2 f 6 In the case of 10,000 years, in addition, for the global warming potential (in CO 2 is a comparison value of 1), CF 4 for 4400, C 2 f 6 6200 (after 20 years), there is a problem of the so-called greenhouse effect that cannot be placed on the earth's environment, and it is expected to establish a 4 、C 2 f 6 PFC as the representative perfluorocarbon method for detoxification

[0004] However, since the C-F bond of perfluorocarbons in PFC is stable (the bonding energy is as high as 130kcal / mol), it is not easy to decompose, and it is very difficult to completely eliminate PFC by general thermal decomposition such as combustion

For example, in pure thermal decomposition, at C 2 f 6 In the case of C-C bonded branches, the decomposition is carried out. Therefore, if the treatment air volume is limited to 250 liters / minute or less at the treatment temperature of 1000 ° C, the detoxification can be carried out, but CF 4 C-F with the largest bonding energy must be cut off, and a high temperature of about 1400-1500°C is required even under the above-mentioned air volume

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