Abstract: An improved fluid distribution head for a plasma processing system characterized by a non-planar dispersion plate provided with a plurality of apertures formed therethrough, and a mechanism for flowing a process gas through the apertures of the dispersion plate. The non-planar dispersion plate is preferably provided with a concave, spherical portion having a radius of curvature of at least four feet. The mechanism for flowing the process gas through the apertures includes an enclosure defining a chamber which communicates with the dispersion plate, a gas inlet communicating with the chamber, and a source of process gas coupled to the gas inlet. The fluid distribution head preferably forms a part of a complete plasma processing system including a wafer pedestal and an R.F. generator coupled to the pedestal to form a plasma between the dispersion plate and the wafer from the process gas flowing from the dispersion plate.