Patent ID: 8512509

Claim:
A gas distribution showerhead assembly for use in a plasma reactor, comprising: a gas supply lid having a bottom surface, and inner and outer gas supply ports in said bottom surface; a manifold plate having top and bottom manifold surfaces, said top manifold surface facing the bottom surface of said gas supply lid; a showerhead plate facing said bottom manifold surface and comprising inner and outer zones, each of said zones comprising an array of plural gas injection orifices extending through said showerhead plate and distributed along both a radial direction and an azimuthal direction; inner and outer gas distribution manifolds, said inner gas distribution manifold comprising: (a) plural inner manifold orifices extending through said manifold plate and distributed along an inner radial location; (b) plural top surface inner channels in said top manifold surface and defining plural top paths of generally equal lengths between said inner gas supply port and respective ones of said inner manifold orifices; (c) plural bottom surface inner channels formed in said bottom manifold surface and defining plural bottom paths of generally equal lengths between respective ones of said inner manifold orifices and respective ones of the plural gas injection orifices of said inner zone.