Patent ID: 8536071
Filing Date: 2013-09-17
Classification: H01J,H01L,Y10T

Abstract:
1. A method of treating a semiconductor substrate in a plasma chamber, said method comprising the steps of: supporting the semiconductor substrate on a lower electrode in the chamber; supplying process gas to the chamber; forming a plasma adjacent an exposed surface of an upper electrode; and processing the semiconductor substrate with the plasma; wherein the upper electrode comprises a showerhead electrode of a showerhead electrode assembly comprising: a backing plate including a plurality of cam locks located in an outer portion of the backing plate; a showerhead electrode having a diameter of over 12 inches and including a central portion and a peripheral portion defined by upper and lower faces of the showerhead electrode, the upper face including a planar surface extending across the central portion, the lower face defined by a planar inner surface extending across the central portion and a stepped outer surface extending across the peripheral portion, the stepped outer surface including an annular planar surface defining an area of increased thickness of the showerhead electrode; a plurality of gas outlets in the central portion of the electrode through which process gas can be delivered to a gap between the showerhead electrode and a lower electrode on which a semiconductor substrate is supported, a plurality of circumferentially spaced apart pockets in the peripheral portion of the upper face, the pockets supporting upwardly extending locking pins engaged with the cam locks of the backing plate so as to clamp the showerhead electrode to the backing plate; and a gasket comprising an annular strip of thermally and electrically conductive material and a plurality of projections on a surface thereof, the annular strip having an outer diameter smaller than an outer diameter of the showerhead electrode, and each of the projections having a height at least two times greater than the thickness of the annular strip compressed between the showerhead electrode and the backing plate, the projections of the gasket located in recesses in the showerhead electrode and the annular strip preventing the upper face of the showerhead electrode from rubbing against a lower face of the backing plate during temperature cycling of the showerhead electrode.