Picometer comb for picometer measurement

Picometer measurement is a key technology in semiconductor lithography, and the existing methods are difficult to meet the accuracy requirements in large-scale measurement due to inherent error and stability problems. In this paper, we proposed the picometer comb as a new approach for picometer measurement. The exposure period of the interferometric field is measured by the scanning reference grating (SRG) method, the one-dimensional picometer comb is made vertically through double-exposure holography, with a picometer-scale difference in periods between two exposures. We found that it can generate a stable light field distribution with an extremely long depth of field and a small divergence angle, the picometer-scale displacement information can be detected by using the axial Moore interference effect of the onedimensional picometer comb. Picometer measurement technology based on the picometer comb is expected to advance the development of future picometer optical components and technologies.