US Patent 7066234 - Anodic Aluminum Oxide Nanoimprinting Stamp

http://www.freepatentsonline.com/7066234.pdf

Nanoimprint lithography is a very promising approach to facilitate less expensive nanopatterning and is more suitable to mass fabrication than some other serial nanofabrication approaches such as scanning probe lithography or e-beam lithography. Basically nanoimprint lithography employs a stamp structure with nanoscopic grooves formed therein which is used to transfer a pattern. However, formation of the nanostamp itself is often a difficult process. This patent employs the use of anodic aluminum oxide (AAO) which have nanoporous structure to form the stamp. Interestingly, in other nanotechnology applications AAO films are also used as templates for growing vertical arrays of carbon nanotubes. Claim 1 reads:

1. Method for producing a stamping tool with a structured stamping surface, comprising the steps of: oxidizing a surface or covering layer of the stamping tool for forming the stamping surface at least partially anodally and forming open hollow chambers that are at least essentially uniformly shaped and at least essentially evenly distributed over the surface or surface area of the stamping surface without the use of a model.