Novel 0.2 mu m i-lithography by phase-shifting on the substrate (POST)

The authors propose a novel i-line lithography by phase-shifting on the substrate (POST). with POST, 0.2 mu m resist patterns have been achieved by using an i-line stepper and conventional masks without phase shifters. It was confirmed that fine patterns were formed by the phase-shifting effect in the resist on the substrate. Simulation suggests that POST has a better resolution than a phase-shifting mask. It has been demonstrated that, with POST, it is possible to define patterns for ULSIs such as the 256 Mbit DRAM by i-line lithography.<>