Optimization of an advanced positive DUV resist for 248 nm L/S pattern printing

Abstract

This paper reports on the results of a NA-sigma optimization study of an advanced positive DUV photoresist, AZ^(R) DX 2058P, on silicon substrate. The contribution starts with the dose-to-clear (E0) swing curve on silicon and continues with a resist thickness selection (Emax and Emin) according to this swing curve. Dose-to-print versus dose-to-clear ratio is in the region of 2.4. Process windows with regard to dense (1:1 L/S) versus isolated CD 0.20 and 0.175 @mm patterns are determined and compared via top-down SEM analysis. Different NA and sigma settings are used in order to optimize the individual and overlapping process latitudes (exposure latitude, EL, and depth-of-focus, DOF). Cross-section SEM pictures will support the results.