Patent ID: 6468385
Filing Date: 2002-10-22
Classification: H01J

Abstract:
A plasma etch chamber comprising:a main chamber having a first cavity, a wafer platform and a spent etchant gas outlet in fluid communication with a pump means for exhausting a spent etchant gas; a middle chamber having a second cavity therein situated inside said first cavity and suspended over said wafer platform; said middle chamber being formed by a top ceramic plate, a bottom ceramic plate and a metal sidewall; said second cavity being in fluid communication with said first cavity through an apertured opening situated in said bottom ceramic plate for feeding an etchant gas plasma into said first cavity, said second cavity being in fluid communication with an etchant gas source through an etchant gas inlet situated in said top ceramic plate; and a bypass conduit providing fluid communication between said second cavity in said middle chamber through an opening in said top ceramic plate and said first cavity in said main chamber such that any residual etchant gas in said second cavity is evacuated by said pump means through said first cavity without causing corrosion in said metal sidewall of said middle chamber, wherein said bypass exhaust conduit allows said residual etchant gas to flow therethrough at a flow rate at least twice the flow rate of said residual etchant gas flown through said apertured opening in said bottom ceramic plate.