关键词: 衍射极限, 可靠度, 对比度, 对版图形, 占空比

Abstract: Abstracts: When the graph size of the pattern is much larger than the diffraction limit, the electromagnetic wave can be considered to propagate along a straight line by the wave-particle duality of electromagnetic waves. Neglecting the effect of diffraction, the statistic requires multiple measurements to satisfy the reliability requirement. Based on the central limit theorem and satisfying the probabilistic requirements, a comb pair checking structure is designed. Through the experiments, it is found that the imaging brightness of the lithography machine will be increased as the number of teeth increases, which is also beneficial to improve the contrast of spatial images. Comparing the light intensity distribution of comb structures with different duty cycles, it is found that the alignment pattern with a duty cycle of 50% is beneficial to improve the contrast of the spatial image and does not affect the alignment operation of the mask during the actual lithography operation, which can meet the process requirements.

Key words: diffraction limit, reliability, contrast, alignment pattern, duty cycle