Complex Spatially-Resolved Reflectometry/Refractometry

Abstract

Apparatus and methods for complex imaging reflectometry and refractometry using at least partially coherent light (121). Quantitative images yield spatially-dependent, local material information about a sample (128, 228) of interest. These images may provide material properties such as chemical composition, the thickness of chemical layers, dopant concentrations, mixing between layers of a sample, reactions at interfaces, etc. An incident beam (123) of VUV wavelength or shorter is scattered off of a sample (128, 228) and imaged at various angles, wavelengths, and / or polarizations. The power of beam (123) is also measured. This data is used to obtain images of a sample's absolute, spatially varying, complex reflectance or transmittance, which is then used to determine spatially-resolved, depth-dependent sample material properties.

Description

[0001]This invention was made with government support under grant number DMR1420620 awarded by the National Science Foundation. The government has certain rights in the invention.FIELD OF THE INVENTION[0002]The field of the present invention is high-resolution, quantitative imaging that can elucidate the depth-dependent composition of samples. In particular, high resolution and high composition sensitivity are achieved by using sub-VUV wavelengths to perform complex imaging reflectometry or refractometry.BACKGROUND OF THE INVENTION[0003]Prior art in the field (US20160187849A1) has described how to perform coherent diffraction imaging with arbitrary angle of incidence, at high numerical aperture, allowing for high resolution images to be collected in transmission or reflection at any incidence angle of the illuminating beam.[0004]Prior art in the field has described imaging reflectometers. U.S. Pat. No. 7,067,818 B2 describes an imaging reflectometer at sub-VUV wavelengths that uses ...

AI Technical Summary

Benefits of technology

[0015]These properties include chemical composition, density, interfacial mixing, dopant concentrations, surface roughness and layer thicknesses. The use of both the reflectivity or transmissivity and phase of a sample for determining material properties makes this a powerful technique that has significantly more sensitivity than the use of the amplitude alone in traditional imaging reflectometry.

[0019]In some cases it is useful to move the sample relative to the incident beam and collect the scattered radiation for multiple values of the independent parameter. The camera may be moved with respect to the scattered radiation to extend the resolution of the imaging system between variations of the independent parameter.

Problems solved by technology

Further, there is no determination of the depth-dependent material properties of the sample.

Most coherent diffraction imaging to date has not been quantitative.

Images