Liquid immersion lithography at 193 nm using a high-NA achromatic interferometer
Résumé
In this paper, we present an immersion interferometer specially designed to be used with a commercial ArF excimer laser. Different configurations are presented enabling the printing of dense lines with a pitch down to 65 nm with an acceptable depth-of-focus. Photoresist patterns are shown at a half-pitch down to 40 nm with nice squared profiles. First polarization studies at high-numerical aperture (NA) have been performed and we noticed a good correlation between roughness and polarization variation at high NA.