Apparatus for evacuating a corrosive effluent gas stream from a processing chamber

An apparatus for evacuating a gas stream of corrosive fluid exhausted from a processing chamber, comprises a dry pumping arrangement 22, a liquid ring pump 26, a separator 34 and an abatement arrangement 40. The liquid ring pump 26 is arranged for evacuating the gas stream of corrosive fluid from the dry pump and at least partially reducing the corrosive fluid content of the gas stream by dissolving the corrosive fluid into a service liquid of the liquid ring pump. The service liquid is preferably water or aqueous solutions that are reactive with, or are suitable solvents for, the gases being pumped. The separator is suitable for separating a gas stream remaining from the service liquid and gas stream mixture exhausted from the liquid ring pump. The abatement arrangement is suitable for treating the separated remaining gas stream exhausted from the separator. The apparatus may be used to treat waste streams containing one or more silicon-containing or halogen-containing gases which are used as a precursor in the manufacture of a semiconductor device.