Novel prism designs for solid immersion optical lithography in the ultra high-NA regime

Abstract

A new prism design has been fabricated and tested experimentally for solid immersion optical lithography of high aspect ratio structures in the ultra high-NA regime using dielectric resonant underlayers. Such a prism design has been made possible through past work that investigated ultra high-NA imaging in the absence of high-force, intimate contact between the sample and solid-immersion medium; key to this is the use of a close index matched prism/IML combination. The work presented here demonstrates the use of a novel prism design for patterning both low and high aspect ratio structures in the ultra high-NA regime; robust and repeatable imaging with such a new prism design is now possible as the prism is not subjected to the large mechanical pressure associated with ultra-fine gap control in dry solid-immersion lithography. The prism presented here allows fabrication for ~58 nm half-pitch line structures over large exposure areas using a 405 nm wavelength exposure.