| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology of removing a harmful component contained in reaction gas generated in etching silicon material with a nitrohydrofluoric solution efficiently at low cost without using an agent for detoxification wherever possible.SOLUTION: Reaction gas is introduced to an alkali aqueous solution as an absorbent in removing a harmful component contained in the reaction gas generated in etching silicon material with an acid mixture liquid containing hydrofluoric acid and nitric acid. The alkali aqueous solution is circulated in a circulation tank until reaching oversaturation, and crystallization product containing the harmful component is formed in the oversaturated alkali aqueous solution, or the crystallization product containing the harmful component is formed in a periphery of a reaction gas introducing part which introduces the reaction gas to the alkali aqueous solution as the absorbent, and the crystallization product is separated to remove the harmful component contained in the reaction gas. |
