Doubling the spatial frequency with cavity resonance lithography

We describe the theory and report the first experimental demonstration of Cavity Resonance Lithography (CRL); a double pattering (DP) technique that can generate patterns on a photoresist 1) with twice the spatial frequency of that of the diffraction limited lithography mask, and 2) at an offset distance that is in the far field of the mask. CRL requires only a single exposure and development step and does not require any additional processes. With commercially available photoresists (PR) and developers, we have recorded a 32.5 nm half-pitch pattern (which is well below the diffraction limit) at an offset distance of 180 nm (which is well beyond the evanescent decay length scales) using 193 nm illumination. We also discuss strategies to improve the minimum feature size and potential implementation schemes. (C) 2011 Optical Society of America