Plasmonic nanolithography

In this paper, we demonstrate high-density nanolithography by utilizing surface plasmons (SPs). SPs are excited on an aluminum substrate perforated with 2-D hole arrays using a near UV light source in order to resolve sub-wavelength features with high transmission. Our lithography experiments using a 365 nm wavelength light source demonstrate 90 nm dot array patterns on a 170 nm period, well beyond the diffraction limit of far-field optical lithography. In far-field transmission measurements, strong UV light transmission and the wavelength-dependent transmission are observed, which confirms the contribution of SPs. Furthermore, an exposure with larger spacing between the mask and photoresist has been explored for potential noncontact lithography.