MODEL BASED OPTICAL MEASUREMENTS OF SEMICONDUCTOR STRUCTURES WITH ANISOTROPIC DIELECTRIC PERMITTIVITY
First Claim
1. A measurement system comprising:
- a first illuminator providing a first amount of illumination to a structure fabricated on an unfinished, multi-layer semiconductor wafer across a spectral range;
a first spectrometer collecting a first amount of light from the structure under measurement in response to the first amount of illumination and generating a first amount of spectral data indicative of a spectral response of the structure under measurement, wherein the first illuminator and the first spectrometer are configured in accordance with a first set of measurement system parameters; and
a fitting analysis module configured to estimate a value of one or more geometric parameters of interest associated the structure under measurement based on a measurement model including an anisotropic characterization of an optical dispersion of the structure under measurement.
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Abstract
Methods and systems for performing optical, model based measurements of a small sized semiconductor structure employing an anisotropic characterization of the optical dispersion properties of one or more materials comprising the structure under measurement are presented herein. This reduces correlations among geometric parameters and results in improved measurement sensitivity, improved measurement accuracy, and enhanced measurement contrast among multiple materials under measurement. In a further aspect, an element of a multidimensional tensor describing the dielectric permittivity of the materials comprising the structure is modelled differently from another element. In a further aspect, model based measurements are performed based on measurement data collected from two or more measurement subsystems combined with an anisotropic characterization of the optical dispersion of the materials under measurement. In another aspect, the characterization of the optical dispersion of one or more materials comprising the structure under measurement depends on the geometry of the structure.
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Citations
27 Claims
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1. A measurement system comprising:
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a first illuminator providing a first amount of illumination to a structure fabricated on an unfinished, multi-layer semiconductor wafer across a spectral range; a first spectrometer collecting a first amount of light from the structure under measurement in response to the first amount of illumination and generating a first amount of spectral data indicative of a spectral response of the structure under measurement, wherein the first illuminator and the first spectrometer are configured in accordance with a first set of measurement system parameters; and a fitting analysis module configured to estimate a value of one or more geometric parameters of interest associated the structure under measurement based on a measurement model including an anisotropic characterization of an optical dispersion of the structure under measurement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method comprising:
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providing a first amount of illumination to a structure fabricated on an unfinished, multi-layer semiconductor wafer across a spectral range; collecting a first amount of light from the structure under measurement in response to the first amount of illumination; generating a first amount of spectral data indicative of a spectral response of the structure under measurement; and estimating a value of one or more geometric parameters of interest associated the structure under measurement based on a measurement model including an anisotropic characterization of an optical dispersion of the structure under measurement. - View Dependent Claims (18, 19, 20, 21, 22)
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23. A measurement system comprising:
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a first illuminator providing a first amount of illumination to a structure fabricated on an unfinished, multi-layer semiconductor wafer across a spectral range; a first spectrometer collecting a first amount of light from the structure under measurement in response to the first amount of illumination and generating a first amount of spectral data indicative of a spectral response of the structure under measurement, wherein the first illuminator and the first spectrometer are configured in accordance with a first set of measurement system parameters; and a non-transitory, computer readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to; estimate a value of one or more geometric parameters of interest associated the structure under measurement based on a measurement model including an anisotropic characterization of an optical dispersion of the structure under measurement. - View Dependent Claims (24, 25, 26, 27)
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Specification