Optical Measurement Of A Highly Absorbing Film Layer Over Highly Reflective Film Stacks

Apparatus and methods for performing optically based film thickness measurements of highly absorbing films (e.g., high-K dielectric films) with improved measurement sensitivity are described herein. A highly absorbing film layer is fabricated on top of a highly reflective film stack. The highly refl...

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Bibliographic Details
Main Authors Krishnan, Shankar, Ygartua, Carlos L
Format Patent
LanguageEnglish
Published 11.04.2019
Subjects
MEASURING
MEASURING ANGLES
MEASURING AREAS
MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS
PHYSICS
TESTING
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Summary:Apparatus and methods for performing optically based film thickness measurements of highly absorbing films (e.g., high-K dielectric films) with improved measurement sensitivity are described herein. A highly absorbing film layer is fabricated on top of a highly reflective film stack. The highly reflective film stack includes one or more nominally identical sets of multiple layers of different, optically contrasting materials. The highly reflective film stack gives rise to optical resonance in particular wavelength ranges. The high reflectance at the interface of the highly absorbing film layer and the highly reflective film stack increases measured light intensity and measurement sensitivity. The thickness and optical dispersion of the different material layers of the highly reflective film stack are selected to induce optical resonance in a desired wavelength range. The desired wavelength range is selected to minimize absorption by the highly absorbing film under measurement.
Bibliography:Application Number: US201816150268