Composite stage for electron enhanced material processing

A direct-current (DC) plasma system for processing of a substrate, comprising:

• a DC plasma reaction chamber configured to contain a DC plasma that is generated between an anode and a cathode of the DC plasma reaction chamber;
• a composite stage arranged in a region of the DC plasma reaction chamber that contains a positive column of the DC plasma, the composite stage comprising a support plate configured to support the substrate;
• and
• a clamp made of an electrically insulating material, the clamp configured to hold the substrate in contact with the support plate, the clamp comprising an annular shape with a central opening that provides an aperture for processing of a central region of the substrate,
• wherein the support plate comprises a plurality of stacked plates, the plurality of stacked plates comprising:
• at least one electrically conductive plate that is configured to receive a biasing signal;
• at least one dielectric plate underlying the at least one electrically conductive plate, and
• at least one dielectric plate overlying the at least one electrically conductive plate, and
• wherein the clamp further comprises an L-shape profile that includes:
• a radial extension of the clamp that is configured to isolate a substrate surface at an outer region of the substrate from the DC plasma, and
• an axial extension of the clamp that is configured to laterally isolate the substrate and the plurality of stacked plates of the support plate from the DC plasma.