Impact of Plasmonic Parameters on 7-nm Patterning in Plasmonic Computational Lithography

For the wavelength reduction to overcome the diffraction limit of the optical lithography, the surface plasmon lithography (SPL) has lower cost and simpler system configuration than the extreme ultraviolet (EUV) lithography. In this paper, for the below 10-nm critical dimension (CD) as one of critical challenges in the lithography technology, SPL based on the SP interference and metamaterial in bowtie and hexahedron structures is proposed and demonstrated by using computer simulations such as the rigorous coupled-wave analysis (RCWA) method and the finite difference time domain (FDTD) method. For 193-nm wavelength, the minimum FWHM (the full width at half maximum) of the transverse magnetic (TM) intensity in xz plane (and yz plane) is 10-nm (and 7-nm) in a bowtie plasmonic structure. For hexahedron structures, the minimum 30-nm FWHM of TM intensity with 193-nm wavelength is improved to the minimum 16-nm FWHM by using metamaterial and SP interference.