| This research examines the feasibility of enhancing aerial image resolution and edge slope of optically patterned features beyond that which is achievable through the use of conventional imaging methods. Emulation of phase-shift mask imaging techniques through the use of acousto-optic interaction, rather than fixed photomasks, will be shown. The phasefront and irradiance profile of a uniform illumination beam were manipulated acousto-optically by controlling the phase and amplitude of the RF signals which drove the acousto-optic modulators used as the basis for these investigations. Emulation of four techniques currently implemented through the use of phase-shift mask lithography was demonstrated using acousto-optic phasefront manipulation. (1) Alternating Phase Shift Mask imaging (Alt-PSM). (2) Attenuated Phase Shift Mask imaging (Att-PSM). (3) Chromeless Phase Lithography (CPL). (4) Vortex Via imaging. Results were modeled using the Beam Propagation Method (BPM) and Fourier transform based algorithms for acoustic and electric field propagation. Results were then verified experimentally, investigating phase transitions in one and two-dimensions, to ensure that physical limitations of the acousto-optic devices would not prevent implementation of this technique. |
