Principle And Method Investigation Of Nanolithography By Localized Surface Plasmon

The local surface plasmon(LSP) direct-writing lithography not only possesses the advantages of simple system structure, flexible lithography pattern, maskless, but more importantly, it can overcome the diffraction limit to reach the ultra-high lithography resolution. As the large-wavelength illumination incoming the nanolithography device based on the sub-wavelength apertures or probe, the LSP resonances would be excited.Taking advantages of the short-wavelength feature of the LSP, the sub-wavelength field distribution could be achieved at the tips of the probes or the edges of the aperture,which could be used for the sub-wavelength lithography. However, due to the exponential decay of evanescent wave components from the exit-plane of the aperture or probe, it requires the device and the photo-resist are contacted closely or separated by a few nanometers. This brings difficulties in accurate device positioning and avoiding photo-resist being scratched. Moreover, the rapid divergence of the light coming from the nano-scale structures inevitably delivers the hot spot with a shallow profile, which confines the development of the LSP direct-writing lithography.Aiming at these problems, through investigating the features of the LSP and its resonances, we proposed a new enhanced LSP nanolithography model which combines the bowtie aperture with metal-insulator-metal(MIM) scheme. Benefiting from this model, the plasmonic hot spot with higher resolution and stronger intensity was achieved. The main innovations of this article are listed below.1、We studied the enhanced transmission principles of the bowtie aperture and its influencing factors.2、A new enhanced LSP nanolithography model was proposed by combining the bowtie aperture with the metal-insulator-metal scheme. Numerical simulations show that the depth profile of the 28 nm FWHM plasmonic spot is more than 25 nm, which is about 4 times that of the bowtie aperture without the MIM scheme.3、Through the demonstration experiment, the smallest spot of 31 nm FWHM was achieved in photo-resist, demonstrating the advantages of the new structure.