US Patent 7744963 - Driving Dip Pen Nanolithography® with electric or magnetic force

http://www.freepatentsonline.com/7744963.html

This patent from Northwestern University has priority going back to 2001 and appears basic to a driving method used by NanoInk in Dip Pen Nanolithography®. Claim 1 reads:

1. A method of nanolithography, comprising:

providing a substrate;

providing a tip comprising an internal cavity having an external opening to the surface of said tip, wherein said opening comprises an internal diameter of less than about 200 nanometers;

loading said cavity with a deposition compound, wherein said deposition compound does not pass through said external opening in the absence of a driving force; and

subjecting said tip to a driving force to deliver said deposition compound through said external opening to be deposited on said substrate;

wherein the driving force is selected from the group consisting of an electrical and a magnetic driving force, wherein, for the electrical driving force, the deposition compound is a charged compound subjected to an applied electric field, and wherein, for the magnetic driving force, the deposition compound is a magnetic compound or a magnetically tagged compound subjected to a magnetic field.