Modulated gap segmented antenna for inductively-coupled plasma processing system

Abstract

An inductively coupled plasma source is provided with a peripheral ionization source for producing a high-density plasma in a vacuum chamber for semiconductor wafer coating or etching. The source has a segmented configuration with high and low radiation segments and produces a generally ring-shaped array of energy concentrations in the plasma around the periphery of the chamber. Energy is coupled from a segmented low inductance antenna through a dielectric window or array of windows and through a segmented shield or baffle. The antenna for the source is a planer coil having at least two windings with the gap between the windings variable or modulated to control the antenna inductance around the antenna. The antenna has a plurality of, for example three, high inductance segments as a result of the conductor windings being closely spaced alternating with low inductance segments as a result of the conductor windings being widely spaced. The antenna and a shield are part of a plasma source. The shield has a plurality of high transparency segments aligning with the high inductance segments of the antenna. The shield may also have one or more additional high transparency segments along the low inductance portions of the antenna enhance formation of a plasma ring in the chamber.