PLUME STEERING

Non-elliptical ion beams and plumes of sputtered material can yield a relatively uniform wear pattern on a destination target and a uniform deposition of sputtered material on a substrate assembly. The non-elliptical ion beams and plumes of sputtered material impinge on rotating destination targets and substrate assemblies. A first example ion beam grid and a second example ion beam grid each have patterns of holes with an offset between corresponding holes. The quantity and direction of offset determines the quantity and direction of steering individual beamlets passing through corresponding holes in the first and second ion beam grids. The beamlet steering as a whole creates a non-elliptical current density distribution within a cross-section of an ion beam and generates a sputtered material plume that deposits a uniform distribution of sputtered material onto a rotating substrate assembly.