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Project Title"Maskless" Nano-Patterning
Track Code2008-079
Short Description

Northwestern researchers have invented a low-cost, "maskless" photolithography method to produce highly uniform arrays of nanopillars and nanoholes over a large area.

#energy #alternative #nanotechnology #lithography #fabrication


The invention uses a self-assembled, ordered monolayer of hexagonally close packed (HCP) micro-spheres as optical lenses to generate deep sub-wavelength regular patterns over a large area on standard photoresist. It has been demonstrated that hole size is relatively independent of microsphere diameter, and so hole diameter is highly uniform even as microspheres vary in size. Microspheres are not formed directly on the substrate surface, which enables the use of any material compatible with a standard photoresist process.

TagsNANOTECHNOLOGY: fabrication, NANOTECHNOLOGY: lithography, ENERGY: alternative
Posted DateApr 11, 2011 6:02 PM


Hooman Mohseni


  • solar cells (especially organic)
  • fuel cells
  • memory devices
  • artificial kidneys
  • nanofiltration
  • photodetectors
  • surface plasmonics
  • photonic crystals


The invention has the following advantages over existing methods by which to form nanoholes and nanopillars:

  • Single Stage: The process is maskless
  • High throughput: Very large area (square meters, in principle) of nano-holes in a single shot
  • Highly Uniform: Hole size is highly uniform
  • Very Small: Hole diameter is much smaller than the wavelength of the UV light source
  • Flexible Dimensions: Hole spacing is independent of hole size
  • Highly Compatible: Can be used for any material compatible with standard lithography



Issued U.S. Patent 8,445,188. Northwestern University seeks a licensing partner to commercialize this invention. 

Contact Information

Arjan Quist, PhD
Invention Associate
(p) 847-467-0305


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