Plasma reactor with electrode array in ceiling

A plasma reactor comprising:

• a chamber body having an interior space that provides a plasma chamber;
• a gas distributor to deliver a processing gas to the plasma chamber;
• a workpiece support to hold a workpiece;
• an electrode assembly comprising a plurality of conductors extending laterally in parallel across at least a region spanning an expected position of the workpiece on the workpiece support in a coplanar array;
• a RF power source to supply a first RF power to the electrode assembly;
• a dielectric bottom plate between the electrode assembly and the workpiece support, the dielectric bottom plate providing an RF window between the electrode assembly and the plasma chamber;
• a dielectric top plate having a lower surface with a plurality of parallel grooves;
• and
• a plurality of filaments in the plurality of grooves between the dielectric top plate and the RF window, each filament comprising a single conductor from the plurality of conductors and a non-metallic shell surrounding the single conductor and positioned between the dielectric top plate and the RF window, wherein the shell forms a conduit and the single conductor extends through the conduit as a solid wire and is suspended in the conduit with a gap surrounding and separating the single conductor from the shell such that the single conductor is spaced apart from an inner floor of the shell.