Thursday, January 31, 2008

US Patent 7323387 - Sub-25 nm fabrication using side walls

Forming lateral dimensions below 25 nm on a semiconductor substrate is a difficult problem for conventional mask based lithography. However, creating a thin film with a thickness below 25 nm is much easier using physical or chemical deposition processes. This patent from Seagate takes advantage of this distinction by deposition on side walls to establish lateral features of less than 25 nm resolution. Claim 1 reads:

1. A method of making a nano structure smaller than 25 nanometers, the method comprising: depositing a nano film onto horizontal and vertical surfaces of a substrate using an atomic layer deposition process; forming a dielectric layer on top of the nano film; and planarizing the dielectric layer and the nano film so that the nano film is positioned between surfaces of the substrate and the dielectric layer and has a top surface with a width of about 25 nanometers or less; and forming a nano trench by etching the nano film positioned between vertical surfaces of the substrate and the dielectric layer.