0.18 mu m KrF lithography using optical proximity correction based on empirical behavior modeling

We present the characterization of optical proximity effects and their corr ection for 0.18 mu m deep-ultraviolet (UV) lithography processes using a se miempirically derived "behavior" model. Since critical dimension (CD) measu rement data for deriving the model are taken after resist pattern transfer into the underlying layer (alpha-Si), the model incorporates all of the dif ferent proximity effect contributors: optics, mask, resist bake, etching, e tc. The modeling technology we use allows for user defined model forms. It was empirically determined that the CD behavior could be adequately describ ed by the diffusion of the aerial image with one Gaussian, and an adjustmen t to the signal threshold based on signal slope. The validity of the model for random geometry was confirmed by comparing contours drawn on Prospector (TM) with two-dimensional configurations of the uncorrected and corrected p arts of a 0.18 mu m test circuit. The model is then used for proximity effe cts correction of the gate level of a 0.18 mu m test design and for the fea sibility study for printing 0.15 mu m features using deep-UV (lambda=248 nm ) lithography. Also, some process window enhancement techniques are evaluat ed in the correction recipe to enlarge the limited process window for print ing 0.175 mu m features. (C) 1998 American Vacuum Society.