SuperScan™: Customized wafer dose patterning

Deliberately non-uniform dose implants are used in the industry to improve device performance across the wafer by compensating for non-uniformities introduced by process steps other than implantation. Varian ion implanters have offered this SuperScan™ capability for close to ten years [1-3]. Recent developments in SuperScan on Varian mid-current implanters significantly expand the ability to deliver virtually any desired dose pattern to wafer. This is accomplished by the introduction of new algorithms allowing custom dose delivery for any scan line and is enabled by the development of an enhanced dose controller and two-dimensional beam profiler. SuperScan 3 is capable of producing centered and off-center patterns without the need for wafer rotation with a zone dose ratio as high as 7:1 while maintaining excellent dose accuracy and uniformity within the different zones.