As the critical dimension shrinks, deterioration of image quality caused by coma aberrations of the lithographic projection optics has become a serious problem in optical lithography. Fast and accurate in-situ measurement techniques for measuring the coma aberration are necessary. In the present paper, we propose a novel method for measuring the coma aberrations of lithographic projection optics by use of a novel mark, which is composed of two fine-segmented phase-shifting gratings and two sufficiently large binary gratings. The coma aberration is extracted from the relative displacements between the phase-shifting gratings and the binary gratings at multiple illumination settings. The PROLITH simulation results show that compared with the TAMIS technique, the measurement accuracy of coma aberration increases by more than 34% under conventional illumination, and the measurement accuracy of low-order coma aberration increases by more than 28% under annular illumination.
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