Nanoscale patterning using photolithography is becoming an active research area that focuses on patterning at small line widths to support high-density electrical device integration. Taking advantage of optical characterization of phase change material (PCM), we propose near-field nanolithography using a reusable Sb65Se35 dual PCM mask to produce sub-diffraction optical aperture. Numerical simulation on the PCM layer was performed to analyze the power absorption, temperature distribution, and corresponding optical aperture. Additionally, numerical simulation of Finite Difference Time Domain (FDTD) was used to analyze the photoresist pattern. To verify the method, photolithography using a dual layer PCM mask was conducted and a photoresist pattern with 39 nm FWHM was obtained. Free from photoresist composed of various points and lines also could be produced through the mask that overcome the diffraction limit.
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