Spatially Resolved Spectroscopic Extreme Ultraviolet Reflectometry for Laboratory Applications

Spatially resolved extreme ultraviolet reflectometry is presented in application to a local characterization of thin non-uniform contamination layers. Sample reflectivity mapping is performed, demonstrating high chemical sensitivity of the technique. Amorphous Al 2 O 3 and carbon are determined as the contaminants of the studied silicon wafer. The results correlate with those obtained by energy-filtering photoemission electron microscopy. A laboratory tool is developed that is capable of multi-angle (2-15) and spectrally broadband (9.5-17 nm) extreme ultraviolet reflectometry at grazing incidence combined with a reduced sample illumination spot size, enabling spatially resolved metrology. A minimum EUV spot size of 25 × 30 m in the sample plane is achieved experimentally.