Sputtering target assembly and method for depositing a thickness gradient layer with narrow transition zone

The present invention relates to a target assembly and its method of use in depositing a layer of material having relatively thin and relatively thick portions adjacent to each other, with a very narrow transition region therebetween. More particularly, the present invention relates to an apparatus and method useful in forming a protective overcoat on a magnetic recording/information storage/read-out disk, wherein the thickness of the overcoat layer in an annularly-shaped inner landing, or CSS, zone of the disk is greater than the thickness of the overcoat layer in an outer, data zone of the disk. The present invention also relates to the formation of coatings, such as optical, anti-friction, wear or corrosion-resistant coatings, which require variation of the properties thereof in a radial direction. Selective deposition of a layer of a material, such as a thick protective overcoat, onto a selected substrate area, such as the inner or CSS landing zone, is achieved using a sputtering target assembly comprising a target/cathode having a planar sputtering surface including an erosion track area, a collimating shield positioned proximate the sputtering surface and surrounding at least a portion of the erosion track area, the collimating shield including an inwardly facing wall, and a blocking shield centrally positioned over the surface of the target/cathode and including an outwardly facing wall, wherein the inwardly facing wall of the collimating shield and the outwardly facing wall, wherein the inwardly facing wall of the collimating shield and the outwardly facing wall of the central blocking shield form an open-ended collimating channel for directing sputtered particles onto the selected substrate area.