A plasma processing device may include a plasma processing chamber, a plasma electrode assembly, a wafer stage, a plasma producing gas inlet, a plurality of vacuum ports, at least one vacuum pump, and a multi-port valve assembly. The multi-port valve assembly may comprise a movable seal plate positioned in the plasma processing chamber. The movable seal plate may comprise a transverse port sealing surface that is shaped and sized to completely overlap the plurality of vacuum ports in a closed state, to partially overlap the plurality of vacuum ports in a partially open state, and to avoid substantial overlap of the plurality of vacuum ports in an open state. The multi-port valve assembly may comprise a transverse actuator coupled to the movable seal plate and a sealing actuator coupled to the movable seal plate.