0.12 /spl mu/m hole pattern formation by KrF lithography for Giga bit DRAM

Dense 0.10 /spl mu/m hole pattern formation has been achieved by optical lithography with KrF wavelength. Double exposure utilizing two alternative phase shift masks of lines and spaces patterns produces dense small hole images with enough focus and exposure latitude. Applying this method with a KrF stepper and chemically-amplified negative-tone resist, a 2-dimensional 0.13 /spl mu/m hole array with a pitch of 0.40 /spl mu/m has been resolved with 1.0 /spl mu/m DOF, and resolution limit size and pitch are less than 0.10 /spl mu/m and 0.28 /spl mu/m, respectively.