Nanometrics Inc.

Svarog LLC

Boris V Kamenev

Michael John Darwin

Apparatus include a polarization state generator situated to provide an interferometer source beam with a region of polarized source light with a polarization state that is in-plane as subsequently incident on a sample and a region of polarized source light with a polarization state that is perpendicular to in-plane as subsequently incident on the sample, and an interferometer unit configured to split the interferometer source beam into test and reference arm beams, to direct the test arm beam to the sample and the reference arm beam to a reference surface, and to recombine the test and reference arm beams to produce an interferometer output beam. Methods use a polarization state generator to produce an interferometer source beam and use an interferometer unit which splits the interferometer source beam into test and reference arm beams.

Thin films and surface topography measurement using polarization resolved interferometry

The properties of a surface of an object in presence of thin transparent films are determined by generating a library of model signals and processing a measurement signal via searching the library to evaluate films properties and topography. The library may be reduced with principal component analysis to enhance computation speed. Computation enhancement may also be achieved by removal of the height contributions from the signal leaving only the film contribution in the signal. The film measurement signal is compared to a library of film signals to determine the film parameters of the sample. The library of film signals is produced by processing each full signal in a library to similarly remove the height contributions leaving only the film contributions. Additionally, a post-analysis process may be applied to properly evaluate local topography.

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Beaverton, OR, United States of America

Boris V Kamenev