Multi-Modal Extreme-Ultraviolet Reflectometer: Solving Inverse Problems in Nanostructure Metrology

Coherent extreme-ultraviolet (EUV) light offers researchers chemical specificity and spatial resolution that is ideal for nanostructure metrology. Combining appropriate physical forward models that capture EUV light-sample interactions and propagation, the experimental data, and optimization routines, one can measure important parameters of nanostructured samples. In this paper, we discuss a unique instrument, designed to characterize the multilayer composition, geometry, topography, and interface quality of various nanostructured samples. We utilize the advantage of coherent EUV light and demonstrate three modes of characterizations, including reflectometry, scatterometry, and coherent diffractive imaging (CDI) reflectometry.