Deep ultraviolet scatterometer for dimensional characterization of nanostructures: system improvements and test measurements

A novel type of deep ultraviolet scatterometer recently developed and set up at PTB has been significantly improved with respect to the dynamic range and the signal-to-noise ratio of the measured scatterograms. The main modifications concern a novel digital data acquisition technique and a new method for the calibration of the applied detectors. With the improved system linewidths (critical dimensions), measurements on periodic structures on a state-of-the-art MoSi photomask have been carried out. The results are compared to those achieved with a scanning electron microscope and a spectroscopic scatterometer.