Contact optical nanolithography using nanoscale C-shaped apertures

Abstract

C-shaped ridge apertures are used in contact nanolithography to achieve nanometer scale resolution. Lithography results demonstrated that holes as small as 60 nm can be produced in the photoresist by illuminating the apertures with a 355 nm laser beam. Experiments are also performed using comparable square and rectangular apertures. Results show enhanced transmission and light concentration of C apertures compared to the apertures with regular shapes. Finite difference time domain simulations are used to design the apertures and explain the experimental results.

Simple analytic modeling of photoresist development profiles in evanescent-field optical lithography

“…There is an ever-increasing interest in developing nanolithography to fabricate ultrasmall features on a variety of integrated optical and electronic devices [1][2][3][4][5]. As derivatives of photolithography, optical near-field lithographic techniques were developed to overcome the diffraction limit of light.…”

“…As derivatives of photolithography, optical near-field lithographic techniques were developed to overcome the diffraction limit of light. However, the evanescent field decaying rapidly from the exit plane of plasmonic nano-sources could be problematic [3,4], owing to shallow exposure depths available for only a few tens of nanometers in photoresists. For fabricating fine features having critical dimension less than about 100 nm, it is not so trivial to determine appropriate exposure dose as well as developing time, which often renders lithographic processes hard to control and may result in poor contrast of fabricated patterns.…”

“…For a prediction of photoresist profiles, the intensity threshold method has been frequently used by finding the isoexposure contour corresponding to the threshold dose of a photoresist [4]. The method, however, was found to yield considerably inaccurate results when forming structures in the subwavelength scale [6], attributed by the oversimplification of a photoresist response to exposure dose.…”

Calculation of three-dimensional profiles of photoresist exposed by localized electric fields of high-transmission metal nano-apertures

“…It is also known that when LSPP is induced on a metal surface, it contributes to the enhanced transmission of light through the nano-apertures [5]. Due to their high transmission, metal nano-apertures have the potential for use in a wide range of applications, such as vertical cavity surface emitting lasers [6] and nanolithography [7,8]. The intensity threshold method was developed to predict pattern profiles obtained by near-field lithography [9].…”

Thermal and mechanical phenomena in nanoscale constrained domains

“…A large amount of work has been done to extend the resolution limit and provide tools and ultrasmall optoelectronic devices for nanomanufacturing such as nanofabricating, nanolithography and nanomodification [2][3][4][5][6][7][8][9][10]. Near-field scanning optical microscope (NSOM) works with resolutions from 10 to 100 nm with apertures and 1 to 20 nm without apertures [11][12][13]. The superlens is capable of imaging features with 60 nm or 1/6 of the illumination wavelength [14].…”