Spot distribution measurement using a scanning nanoslit

A scanning and rotating nanoslit is used to measure submicrometer features in focused spot distributions. Using a filtered backprojection technique, a highly accurate reconstruction is demonstrated. Experimental results are confirmed by simulating the scanning slit technique using a physical optics simulation program. Analysis of various error mechanisms is reported, and the reconstruction algorithm is determined to be very resilient. The slit is 125 nm wide and 50 μm long and is fabricated on a 120 nm thick layer of aluminum. The size of the image field is 15 μm, and simulations indicate that 200 nm Rayleigh resolution is possible with an infinitely narrow slit.