Ptychography as a wavefront sensor for high-numerical aperture extreme ultraviolet lithography: analysis and limitations

Wavefront aberration measurements are required to test an extreme ultraviolet (EUV) imaging system. For a high-NA EUV imaging system, where conventional wavefront-sensing techniques show limitations, ptychography can be used for this purpose. However, at the wavelength region of EUV (i.e., 13.5 nm), the position accuracy of the scanning mask that is defined for ptychography is stringent. Therefore, we propose ptychography combined with mask position correction. The simulated intensity patterns, the ones we use, resemble expected EUV experimental data. Finally, we show the results in the presence of Poisson noise and the tolerance of the position correction method for error in mask positions.