Patent ID: 9099398
Filing Date: 2015-08-04
Classification: B05B,B05D,C23C,H01J,H01L

Abstract:
1. A ceramic showerhead of uniform thickness configured to form a vacuum wall at the top of 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, axially extending gas holes having diameters of less than 0.06 inch and aspect ratios of at least 2 located in an annular zone on an outer portion and extending between 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 upper plate of ceramic material having planar upper and lower surfaces, the upper plate overlying the lower plate such that a plenum is located between opposed surfaces of the upper and lower plates and the gas holes are in fluid communication with the plenum.