Nonuniform self imaging of achromatic Talbot lithography

Achromatic Talbot lithography (ATL) with high resolution has been demonstrated to be an excellent technique for large area periodic nano-fabrication. In this work, the uniformity of pattern distribution in ATL was studied in detail. Two ATL transmission masks with ~50% duty cycle in a square lattice were illuminated by a spatial coherent broadband extreme ultraviolet beam with a relative bandwidth of 2.38%. Nonuniform dot size distribution was observed by experiments and finite-difference time-d