Analysis of Sub-0.15 µm Pattern Replicationin Synchrotron Radiation Lithography

Abstract

An absorber profile is essential when replicating deep quarter-micron patterns because of the X-ray phase-shifting effect in the absorber. We have compared experimental results of 0.15 µm line-and-space (L/S) pattern with calculation based on Fresnel diffraction using the measured absorber profile and resist property. The experimental mask had a beveled absorber edge profile, and the 0.15 µm L/S exposure latitude values obtained with this mask are ±6% for a 30 µm gap, ±8% for 20 µm, and ±12% for 10 µm. The calculation showed good coincidence with respect to the dependence of the latitude on the gap, but the calculated pattern size is about 0.05 µm less than the experimental one. Simulation on the 0.1 µm L/S printability was further carried out for a 20 µm gap. Although the applied exposure dose was rather small, the pattern was resolved by the beveled-edge mask with a mask contrast of about 6.