Plasmonic Nanofocusing in Deep and Extreme Sub-Wavelength Scale for Scalable Nanolithography

Maskless nanolithography is an agile and cost effective approach if their throughputs can be scaled for mass production purposes. Using plasmonic nanolithography approach, direct pattern writing was successfully demonstrated with 22 nm half-pitch at high speed. Plasmonic nanolithography uses an array of plasmonic lenses to directly pattern features on a rotating substrate. Taking the advantage of air bearing surface techniques, the system can expose the wafer pixel by pixel with a speed of ∼10 m/s, much faster than any conventional scanning based lithography system. It is a low-cost, high-throughput maskless approach for the next generation lithography and also for the emerging nanotechnology applications, such as nanoscale metrology and imaging. A critical part of the PNL is to use plasmonic lens to deliver highly concentrated optical power at nanoscale. We have demonstrated such nanoscale process and achieved 22 nm resolution. Here, we report our recent efforts of designing new plasmonic nanofocusing structures that is capable of achieving optical confinement below 20 nm which can potentially support direct patterning at sub-10nm resolution.