Printing characteristics of proximity x-ray lithography and comparison with optical lithography at 100 and 70 nm technology nodes

The printing characteristics of proximity x-ray lithography (PXL) were comp ared with those of ArF and F-2 Optical lithography using model patterns of memory and logic devices at 100 and 70 nm technology nodes. Aerial-image si mulations of both optical lithography and PXL were carried out, and exposur e experiments were performed to confirm the simulation results for PXL. Bot h the aerial images and the exposure results show that PXL has sufficient r esolution for patterns with a 100 nm minimum feature size without the need for any additional resolution enhancement techniques (RETs). It exhibits be tter pattern printing fidelity than either ArF or F-2 lithography with stro ng RETs, such as an alternate-type phase shift mask and off-axis illuminati on techniques. PXL provides a wide latitude ton the order of microns) in th e proximity gap, and is robust with regard to critical dimension errors in mask patterns. For the optical Lithography, the fidelity for complex patter ns and the narrow depth of focus (DOF) are still issues to be resolved. At the 70 nm node, PXL provides acceptable resolution even at a gap of 10 mum, while F-2 lithography requires further advanced RETs to achieve sufficient resolution and an acceptable DOF. (C) 2001 American Vacuum Society.