Cleaning method for exhaust gas containing ammonia and silane
AssigneeJapan Pionics Co., Ltd.
InventorsYasu Ishii, Noboru Akita
Life of this patent
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Abstract
A cleaning method for an exhaust gas containing ammonia, silanes, and organometallic compounds exhausted from a nitride film production step, etc., for producing compound semiconductors. After removing the silanes and the organometallic compounds from the exhaust gas by contacting the exhaust gas with a cleaning agent comprising soda lime having provided thereon a copper(II) salt, the exhaust gas is contacted with an ammonia decomposition catalyst to decompose ammonia into hydrogen and nitrogen, and undecomposed ammonia in the remaining exhaust gas is then removed by a cleaning agent comprising an inorganic carrier having provided thereon a copper(II) salt, or an active carbon having provided thereon copper sulfate.
Claims21
A cleaning method for an exhaust gas containing ammonia, silanes, and organometallic compounds, which comprises contacting the exhaust gas with a cleaning agent A comprising soda lime or soda lime having provided thereon a copper(II) compound to remove the silanes and the organometallic compounds, contacting the exhaust gas thus treated with an ammonia decomposition catalyst comprising an inorganic carrier having provided thereon at least one kind of a metal selected from the group consisting of nickel, iron, and palladium to decompose ammonia in the exhaust gas into hydrogen and nitrogen, and then contacting the remaining exhaust gas with a cleaning agent B comprising an active carbon having provided thereon copper sulfate, or an inorganic carrier having provided thereon a copper(II) salt to remove undecomposed ammonia, thereby resulting in a cleaned exhaust gas containing about 25 ppm or less of ammonia.
Dependencies are inferred from the claim text.