Abstract: A plasma generation electrode array for a plasma processing tool is described. The plasma processing tool comprises a processing chamber and a substrate table therein for supporting a substrate in use on which material is to be deposited and/or etched. The electrode array comprises a plurality of ground electrodes and at least one live electrode, the plurality of ground electrodes not being in electrical contact with the at least one live electrode, and arranged such the ground electrodes and live electrode(s) alternate with one another along a first direction in a first plane which is substantially parallel to the substrate table in use. The ground and live electrodes are spaced from one another along the first direction, wherein each of the ground and live electrodes extends from a base thereof to a distal end thereof in a second direction which is substantially perpendicular to the first plane.