Dip Pen Nanolithography (DPN) is a method developed at Northwestern University for depositing thin organic films in patterns with feature sizes of around 10 nm (about 20 times better than the best optical lithography). By coating an Atomic Force Microscope (AFM) tip with an ink, the scientists are able to deposit well defined lines of the ink in a manner similar to a traditional ink pen. While such molecular scale precision is quite a feat, similar precision has been achieved with other methods. However, this particular method for patterned film deposition can be operated in parallel because the deposition is independant of the applied force [1], making DPN a promising approach to nanolithography.

Reference:

[1] Seunghun Hong, Chad A. Mirkin, "A Nanoplotter with Both Parallel and Serial Writing Capabilities" (2000) Science 288, 5472, 1808 - 1811. Abstract