A plasma processing system for treating a substrate includes a processing chamber including a first chamber portion configured to receive a first gas for providing a plasma space, and a second chamber portion configured to receive a second gas for providing a process space having process chemistry to treat the substrate. A substrate holder is coupled to the second chamber portion of the processing chamber, and configured to support the substrate proximate the process space, and a plasma source is coupled to the first chamber portion of the processing chamber, and configured to form a plasma in the plasma space. A grid is located between the plasma space and the process space, and configured to permit the diffusion of the plasma between the plasma space and the process space in order to form the process chemistry from the process gas.