Patent ID: 6949225

Claim:
An apparatus for treating a waste gas containing fluorine-containing compounds from a semiconductor fabrication process, comprising: a solids treating device for removing solids and acidic gases including Si compounds from a waste gas containing fluorine-containing compounds; an addition device for adding H 2 and/or H 2 O and O 2 as a decomposition assist gas to the waste gas discharged from said solids treating device; a thermal decomposition device for decomposing into acidic gases and CO 2 perfluorocarbons, oxidizing gases and CO discharged from said solids treating device and to which the decomposition assist gas has been added, said thermal decomposition device comprising a preheating chamber and a catalyst chamber packed with γ-alumina to be heated to 500° C. to 1000° C.; an acidic gas treating device for removing acidic gases discharged from said thermal decomposition device; a supply line for supplying the waste gas into said solid treating device; a first line interconnecting said solids treating device and said thermal decomposition device, and a second line interconnecting said thermal decomposition device and said acidic gas treating device; a discharge line for discharging treated gas from said acidic gas treating device; a bypass interconnecting said supply line and said discharge line, said bypass having a bypass valve such that upon actuation of said bypass valve the waste gas is conveyed from said supply line to said discharge line without entering said solids treating device; an air ejector, positioned in said discharge line, for maintaining a negative pressure in each of said solids treating device, said thermal decomposition device, said acidic gas treating device and said first and second lines; and an analyzer, positioned immediately upstream of said air ejector, for controlling emission density of the treated gas discharged from said acidic gas treating device.