SF Bay Area Nanotechnology Council


Sub-5 nm Patterning Using Helium Ion Beam and Nanoimprint Lithography

Wei-WuTuesday June 10, 2014
Noon Р1  pm
Texas Instruments (TI) Auditorium E-1
2900 Semiconductor Drive
Santa Clara, CA



TITLE: Sub-5 nm Patterning Using Helium Ion Beam and Nanoimprint Lithography

SPEAKERS: Prof. Wei Wu, Department of EE, University of Southern California

Helium ion beam lithography (HIBL) is a recently developed nanolithography technology. It uses a He ion beam to direct write patterns in the same fashion as electron beam lithography (EBL). Due to its advantages, such as smaller focusing spot and less proximity effects than electron beam, it can go beyond the resolution of EBL. We have demonstrated patterning of various nano-patterns using HIBL. For example, we achieved dense lines with half-pitch down to 4 nm. Moreover, we also achieved sub-5 nm patterning using nanoimprint lithography (NIL) with molds fabricated by HIBL. The combination of NIL and HIBL mitigates the two major drawbacks of HIBL: low throughput and the tendency to damage substrates. We also used HIBL as a direct milling tool to pattern metal and Graphene with dense lines down to 4 nm half-pitch. Our Raman spectra show that the HIBL patterned Graphene nanoribbons (GNRs) have lower line-edge roughness than reported GNRs patterned by EBL.

Dr. Wei Wu graduated from Peking University with a BS in Physics in 1996, and received a Ph.D. in Electrical Engineering from Princeton University in 2003. He joined the Ming Hsieh Department of Electrical Engineering at the University of Southern California as an associate Professor January, 2012. Before joining USC, he worked as a senior scientist at HP labs. His work includes high-resolution nano-fabrication and applications in nano-photonics, nano-electronics, renewable energy harvesting and chemical sensing. He coauthored 80 peer reviewed journal papers, 1 book chapter and more than 80 conference presentations. He has 64 granted US patents and 52 pending applications. He is co-editor of Applied Physics A.


  • 11:30 am – Registration & light lunch (pizza & drinks)
  • Noon – Presentation & Questions/Answers
  • 1:00 pm -¬†Adjourn

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