Patent ID: 7673583
Filing Date: 2010-03-09
Classification: H01J

Abstract:
1. An antenna for an ICP source that produces a high-density inductively coupled plasma in a vacuum chamber of a semiconductor wafer processing apparatus, the antenna comprising: a conductor having a plurality of windings around a central axis, the windings defining a surface having a plasma side for facing into a processing space within the chamber and an outer side for facing away from the processing space; the conductor being configured to provide the antenna with a segmented configuration including: a plurality of high efficiency sections spaced at equal angular intervals around the axis and configured to concentrate current therein and produce relatively high strength magnetic fields adjacent to the conductor on said plasma side thereof, and a plurality of low efficiency sections spaced at equal angular intervals around the axis between adjacent high efficiency sections and configured to more widely distribute current therein and produce relatively low strength magnetic fields adjacent to the conductor on said plasma side; the high and low efficiency sections being alternately arranged in a ring so as to couple power from said plasma side into the processing space within the chamber to energize a plasma in the processing space in an annular alternating high and low power density distribution; the conductor having a plurality of 360 degree loops therein, one in each of a plurality of the high efficiency sections, equally spaced around the axis, and extending away from the plasma side of the conductor in a perpendicular direction, each 360 degree loop having parallel ends lying in the winding on said surface and through which current that flows in the winding flows in the same direction parallel to said winding, and having a return section between said ends spaced from said surface on the outer side thereof through which said current flows parallel to said winding in the opposite direction of the current through said ends; whereby current through said parallel ends of each 360 degree loop enhances the strength of the magnetic fields on the plasma side of said surface adjacent the high-efficiency sections, increasing the efficiency thereof in coupling of power into the processing space to energize high density portions of the plasma, to produce an annular, ring-shaped, segmented plasma of alternating high and low plasma density regions spaced at equal angular intervals around the central axis of the vacuum chamber.