The circular FFE sources has been developed to allow the tuning of coating uniformity via the speed of rotation of the magnetic system. bellow is a graph to illustrate the coating of 200mm wafers by a Gencoa 350FFE (Full Face Erosion) type magnetron source. The ability to tune the uniformity by a non-intrusive speed parameter allows different materials and process parameters to be used without changes to the deposition tool. By changing the speed uniformity of a fraction of a percent can be achieved via the rotational speed control of the spinning magnetic array and hence the plasma movement over the target surface.