Method and apparatus for angular-resolved spectroscopic lithography characterization
First Claim
Patent Images
1. A scatterometer, comprising:
- an illumination source configured to produce a first beam directed to a reflector and a second beam directed to an element;
the reflector configured to reflect the first beam at different first and second angles to reflect corresponding first and second images; and
detecting system having;
a first part configured to combine the first and second images to determine an illumination profile of the first beam, anda second part configured to measure a spectrum of the second beam reflected from a surface of the element,wherein a property of the element is determined by measuring a property of the reflected spectrum at a plurality of angles simultaneously, wherein the illumination profile is used to correct determinations of the property of the reflected spectrum at diffraction orders higher than ±
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Abstract
An apparatus and method to determine a property of a substrate by measuring, in the pupil plane of a high numerical aperture lens, an angle-resolved spectrum as a result of radiation being reflected off the substrate. The property may be angle and wavelength dependent and may include the intensity of TM- and TE-polarized radiation and their relative phase difference.
199 Citations
15 Claims
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1. A scatterometer, comprising:
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an illumination source configured to produce a first beam directed to a reflector and a second beam directed to an element; the reflector configured to reflect the first beam at different first and second angles to reflect corresponding first and second images; and detecting system having; a first part configured to combine the first and second images to determine an illumination profile of the first beam, and a second part configured to measure a spectrum of the second beam reflected from a surface of the element, wherein a property of the element is determined by measuring a property of the reflected spectrum at a plurality of angles simultaneously, wherein the illumination profile is used to correct determinations of the property of the reflected spectrum at diffraction orders higher than ±
1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An inspection method, comprising:
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projecting a radiation beam onto a substrate; and measuring, in a pupil plane of a high numerical aperture lens, a spectrum of the radiation beam reflected from a pattern printed on the substrate; combining first and second images to determine an illumination profile of the radiation, wherein the first and second images are reflected off of a reflector at different angles, wherein a tilting of the reflector is adapted to generate the first and second images, and wherein a property of the substrate is calculated from the measured spectrum and wherein the illumination profile is used to correct determinations of a property of the reflected spectrum at higher diffraction orders. - View Dependent Claims (12, 13, 14, 15)
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Specification