Small-field exposure system for 193-nm lithography

Abstract

A small-field ArF excimer laser-based exposure tool has been designed and fabricated for 193-nm lithography research and for exposure tool development. The projection optics based upon the Schwartzchild concept have a 3-mm field diameter, a 5:1 reduction ratio, and a 0.5 NA. The exposure tool uses an unnarrowed ArF excimer laser as a light source and a fly's eye homogenizer to produce a reticle illumination uniformity of < 5% RMS/pulse. The results from preliminary exposures with PMMA (poly-methyl-methacrylate) and TER-1 resist coincided with the simulation results and with expectations. Also, advanced imaging tests was carried out for various resists. We report the detailed system parameters and the characterization data for the small-field ArF excimer laser exposure tool and some of advances in 193 nm lithography that have been achieved with the system.