Abstract: Lithography simulation was used to calculate the influence of high-NA illumination on resolution, depth-of-focus, and exposure latitude evaluating the aerial image. Contour plots of exposure latitude versus NA & $sigma at constant depth-of- focus values were calculated for dense lines, single contacts and isolated lines. All features were investigated using standard illumination and enhancement techniques (PSMs and/or annular illumination). For standard illumination the maximum exposure latitude is achieved for the highest NA possible if only small depth-of-focus is required e.g. thin resist layers over nearly plain or planarized substrates. In a production environment higher depth-of-focus values are necessary. In this case the optimum NA moves to lower values even for feature sizes near the resolution limit. However, in combination with PSMs (and/or annular illumination) the best conditions move to higher NA with decreasing feature sizes. !5
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