Profile characterization using optical diffraction microscopy

Recent developments in optical profile characterisation using optical diffraction microscopy are described. Grating profiles are characterized from the measured diffraction efficiencies. The surface topography is found by varying model topography and matching the calculated and measured diffraction efficiencies. The model parameters include height, filling degree and sidewall angles. In the present work the method has been applied to gratings having various material composition. A series of gratings with periods ranging from 399 nm to 1245 nm has been investigated. It is shown that optical diffraction microscopy is a simple and fast method for retrieving grating profiles and the material boundary between the grating materials. The results show good agreement with atomic force microscope measurements.