Characterization of proximity correction in 100-nm-regime X-ray lithography

The possibility and usefulness of proximity correction in 100-nm-regime X-r ay lithography was examined. Two-dimensional array patterns of around 100 n m linewidth were fabricated by e-beam exposure and subsequent gold electrop lating. The mask patterns consist of normal rectangular patterns and shape- modified patterns which are modified by a simple optical proximity correcti on (OPC)-like method such as the addition of a simple serif at the end of t he pattern. Different serifs sizes and pattern shapes were considered. The delineated images printed by normal rectangular mask pattern and shape-modi fied mask patterns were compared with a target image to be defined on the w afer, and the faithfulness of printed images was determined by measuring th e lengths and widths at all the significant points on two-dimensional patte rns. The OPC-like mask modification technique had positive effects in impro ving the fidelity of the printed image in the linewidth range below 150 nm, especially in the reduction of image shortening in array patterns. The opt imum serif size depends on the pattern size, pattern density and the proces s conditions, especially the gap between the mask and wafer In addition, tw o-dimensional aerial image simulations were performed and compared with exp erimental results and showed the same results as the experiments.