An apparatus for plasma processing includes a first plasma source, a first planar electrode, a gas distribution device, a plasma blocking screen and a workpiece chuck. The first plasma source produces first plasma products that pass, away from the first plasma source, through first apertures in the first planar electrode. The first plasma products continue through second apertures in the gas distribution device. The plasma blocking screen includes a third plate with fourth apertures, and faces the gas distribution device such that the first plasma products pass through the plurality of fourth apertures. The workpiece chuck faces the second side of the plasma blocking screen, defining a process chamber between the plasma blocking screen and the workpiece chuck. The fourth apertures are of a sufficiently small size to block a plasma generated in the process chamber from reaching the gas distribution device.