0.12 mu m hole pattern formation by KrF lithography for giga bit DRAM

Dense 0.10 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 pattern produces dense small hole images with enough focus and exposure latitudes. Applying this method with a KrF stepper and chemically-amplified negative-tone resist, 2-dimensional 0.13 mu m hole array with the pitch of 0.40 mu m has been resolved with 1.0 mu m DOF, and resolution limit size and pitch are less than 0.10 mu m and 0.28 mu m, respectively.