Scanning Phase-Mask DUV Inscription of Short-Period Large-Area Photoresist Gratings

We present an approach for periodical structuring of large-area photoresist gratings with short periods based on a deep-ultraviolet (DUV) lithography process. Our procedure of inscribing gratings on planar surfaces using a scanning phase-mask interferometer and including a technique for suppressing the disturbing influence of the zeroth-order diffraction is demonstrated and compared to well-established methods. Applying this approach, large-area, centimeter-scale chirped photoresist gratings with a central period of 225 nm, a chirp rate of 0.5 nm/cm and a duty cycle of 50% have been fabricated on planar silicon chips.