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US 7,053,991 B2Granted
Differential numerical aperture methods
AssigneeAccent Optical Technologies, Inc.
InventorJohn V. Sandusky
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Abstract
Methods for differential numerical aperture analysis of samples, utilizing angle-of-incidence measurements resulting from variable illumination or observation numerical apertures, or both. Metrology applications are provided, and more particularly including scatterometer, ellipsometer and similar analysis methods, including bi-directional reflectance or transmission distribution function measurement.
Claims19
A method for determining parameters of a structure disposed on a wafer comprising the steps of:
- generating a beam of light focused on a structure disposed on a wafer;
- providing an illumination and observation numerical aperture, the illumination numerical aperture being disposed along the incident path of the beam of light and the observation numerical aperture being disposed along the reflected path of the beam of light;
- differentially changing the aperture of at least one of the illumination and observation numerical apertures;
- detecting and characterizing the scattered light along the reflected path;
- and
- determining parameters of the structure.
3 more elements
Dependencies are inferred from the claim text.