Euv Photolithography Mask Inspection Using Fourier Ptychography

We use a synchrotron-based full-field EUV microscope with variable angle of illumination to perform Fourier ptychography reconstruction of patterned EUV photo-masks. We show that the reconstruction brings accurate quantitative phase information by comparing with through-focus data, and a 1.7-fold increase in resolution over the diffraction-limit by comparing with data acquired with larger numerical aperture. We also show how the complex-valued images reconstructed using Fourier ptychography can effectively be used for experiment-based computational lithography.