Patent ID: 8562785
Filing Date: 2013-10-22
Classification: B05B,B05D,C23C,H01J,H01L

Abstract:
1. A ceramic showerhead in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, comprising: a lower plate of ceramic material having a planar lower surface and a stepped upper surface which is thicker in a central portion thereof and thinner in an outer portion thereof, axially extending gas holes located in an annular zone on the outer portion and extending between the upper and lower surfaces, a vacuum sealing surface located on the outer portion at an outer periphery of the lower surface, and inner and outer vacuum sealing surfaces on the upper surface defining the annular zone in which the axially extending gas holes are located; an annular upper plate of ceramic material having planar upper and lower surfaces, a plurality of radially extending gas passages extending inwardly from an outer periphery thereof, and a plurality of axially extending gas passages extending from the lower surface thereof to the radially extending gas passages; the annular upper plate configured to surround the central portion of the lower plate and overlie the upper surface of the outer portion of the lower plate such that the axially extending gas passages of the upper plate are in fluid communication with the axially extending gas holes in the lower plate.