Breaking the feature sizes down to sub-22 nm by plasmonic interference lithography using dielectric-metal multilayer.

We have developed the plasmonic interference lithography technique to achieve the feature sizes theoretically down to sub-22 nm even to 16.5 nm by using dielectric-metal multilayer (DMM) with diffraction-limited masks at the wavelength of 193 nm with p-polarization. An 8 pairs of GaN (10 nm)/Al (12 nm) multilayer is designed as a filter allowing only a part of high wavevector k (evanescent waves) to pass through for interference lithography. The analysis of the influence by the number of DMM layers is presented. 4 pairs of the proposed multilayer can be competent for pattern the minimal feature size down to 21.5 nm at the visibility about 0.4 to satisfy the minimum visibility required with positive resist. Finite-difference time-domain analysis method is used to demonstrate the validity of the theory.