Methods and systems for performing measurements of
semiconductor structures based on high-brightness, polychromatic, reflective small angle x-
ray scatterometry (RSAXS)
metrology are presented herein. RSAXS measurements are performed over a range of wavelengths, angles of incidence, and
azimuth angles with small illumination beam spot size, simultaneously or sequentially. In some embodiments, RSAXS measurements are performed with x-
ray radiation in the soft x-
ray (SXR) region at
grazing angles of incidence in the range of 5-20 degrees. In some embodiments, the x-ray illumination source size is 10 micrometers or less, and focusing
optics project the
source area onto a
wafer with a demagnification factor of 0.2 or less, enabling an incident x-ray illumination spot size of less than two micrometers. In another aspect, active focusing
optics project programmed ranges of illumination wavelengths, angles of incidence, and
azimuth angles, or any combination thereof, onto a
metrology area, either simultaneously or sequentially.