Patent ID: 7464662
Filing Date: 2008-12-16
Classification: H01J

Abstract:
1. A plasma processing apparatus comprising: a vacuum processing chamber having a substrate support therein centered on a central axis of the chamber; a chamber wall enclosing a plasma processing space within the chamber proximate the substrate support, the chamber wall having a dielectric window therein centered on the central axis, the dielectric window having a vacuum chamber side and an outside; an ICP source coupled to the chamber, the source including an RF power source outside of the chamber and means for coupling RF energy from the RF power source into the plasma processing space within the chamber in a spatially distributed ring, around and centered on the axis, in an alternating high and low plasma density distribution; the means for coupling including an inductor outside of the chamber having a conductor formed of a sheet of electrically conductive material in the shape of at least one loop having opposite edges encircling the axis, the sheet having a gap extending between the opposite edges and defining a pair of terminal ends connected to the RF power source; the opposite edges including an inner edge and an outer edge each having a plurality of cutouts therein, including inner cutouts in the inner edges and outer cutouts in the outer edges alternately spaced around the axis, that require RF current flowing between the terminal ends to flow around the outside of the inner cutouts and to flow around the inside of the outer cutouts, so as to concentrate near the cutouts RF magnetic fields extending into the plasma processing space to energize segments of high plasma density in the processing space in the alternating high and low plasma density distribution; the cutouts in the outer edge extending sufficiently radially inward to interrupt the shortest current paths around the outside of the cutouts in the inner edge and the cutouts in the inner edge extend sufficiently radially outward to interrupt the shortest current paths around the inside of the cutouts in the outer edge; the opposite edges thereby defining a sinuous serpentine conductive path that alternately curves inwardly around the outside of the cutouts in the inner edge and curves outwardly around the inside of the cutouts in the outer edge, in a plurality of oscillations between the terminal ends; the at least one loop including a series of segments of alternating large and small cross-sections having widths generally parallel to the dielectric window and thicknesses generally perpendicular to the dielectric window.