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30 July 2002 Illumination, mask, and tool effects on pattern and probe-based aberration monitors
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The practicality and manufacturability of pattern and probe-based aberration monitors for characterizing optical lithography tools in light of tool and mask performance issues is investigated via simulation. The effects of the partial coherence of the illumination, the use of off-axis illumination, alignment optics obscuration, mask pixel size, and intensity imbalance effects on the ability of the pattern and probe aberration monitors to quantify residual aberrations at levels approaching 0.01(lambda) rms is assessed. Targets from nine rectangles to over 100 rectangles, in sizes up to seven rings were simulated with SPLAT under various illumination conditions. Results show that the targets respond best for nearly coherent illumination ((sigma) equals 0.1 to 0.2). Phase-compensation for reversal in sign of the mutual coherence function is shown to be feasible and will be essential for off-axis illumination. While the intensity imbalance for phase shifting masks can be significant, the affect on the aberration measurement is relatively small.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Garth Robins and Andrew R. Neureuther "Illumination, mask, and tool effects on pattern and probe-based aberration monitors", Proc. SPIE 4691, Optical Microlithography XV, (30 July 2002);


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