Metrology Tool With Combined X-Ray And Optical Scatterometers
First Claim
1. A metrology tool comprising:
- a liquid metal based x-ray illumination system including a liquid metal x-ray illumination source and x-ray illumination optics configured to shape and direct an incident x-ray beam from the x-ray illumination source to an inspection area of a specimen;
an x-ray detector configured to receive radiation from the specimen in response to the incident x-ray beam and generate signals indicative of a first property of the specimen;
an optical illumination system including an optical illumination source and optical illumination optics configured to shape and direct an incident optical illumination beam from the optical illumination source to the inspection area of the specimen simultaneous with the incident x-ray beam, wherein the incident optical illumination beam and the incident x-ray beam spatially overlap at the inspection area of the specimen; and
an optical detector configured to receive optical radiation from the specimen in response to the incident optical illumination beam and generate signals indicative of a second property of the specimen.
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Accused Products
Abstract
Methods and systems for performing simultaneous optical scattering and small angle x-ray scattering (SAXS) measurements over a desired inspection area of a specimen are presented. SAXS measurements combined with optical scatterometry measurements enables a high throughput metrology tool with increased measurement capabilities. The high energy nature of x-ray radiation penetrates optically opaque thin films, buried structures, high aspect ratio structures, and devices including many thin film layers. SAXS and optical scatterometry measurements of a particular location of a planar specimen are performed at a number of different out of plane orientations. This increases measurement sensitivity, reduces correlations among parameters, and improves measurement accuracy. In addition, specimen parameter values are resolved with greater accuracy by fitting data sets derived from both SAXS and optical scatterometry measurements based on models that share at least one geometric parameter. The fitting can be performed sequentially or in parallel.
81 Citations
20 Claims
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1. A metrology tool comprising:
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a liquid metal based x-ray illumination system including a liquid metal x-ray illumination source and x-ray illumination optics configured to shape and direct an incident x-ray beam from the x-ray illumination source to an inspection area of a specimen; an x-ray detector configured to receive radiation from the specimen in response to the incident x-ray beam and generate signals indicative of a first property of the specimen; an optical illumination system including an optical illumination source and optical illumination optics configured to shape and direct an incident optical illumination beam from the optical illumination source to the inspection area of the specimen simultaneous with the incident x-ray beam, wherein the incident optical illumination beam and the incident x-ray beam spatially overlap at the inspection area of the specimen; and an optical detector configured to receive optical radiation from the specimen in response to the incident optical illumination beam and generate signals indicative of a second property of the specimen. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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simultaneously illuminating a specimen with an x-ray illumination beam and an optical illumination beam such that the x-ray illumination beam and the optical illumination beam spatially overlap at a desired inspection area on a surface of the specimen; detecting an amount of optical radiation from the specimen in response to the optical illumination beam incident on the specimen; detecting an amount of x-ray radiation from the specimen in response to the x-ray illumination beam incident on the specimen; generating a first signal indicative of a first property of the specimen in response to the detected amount of optical radiation; and generating a second signal indicative of a second property of the specimen in response to the detected amount of x-ray radiation. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A non-transitory, computer-readable medium, comprising:
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code for causing a computer to generate a geometric model of a structure of a specimen simultaneously illuminated by an x-ray illumination beam and an optical illumination beam such that the x-ray illumination beam and the optical illumination beam spatially overlap at a desired inspection area on a surface of the specimen; code for causing the computer to generate an optical response model and an x-ray response model based at least in part on the geometric model, wherein both the optical response model and the x-ray response model include at least one common geometric parameter from the geometric model; code for causing the computer to receive a first signal indicative of an amount of optical radiation detected from the specimen in response to the optical illumination beam; code for causing the computer to receive a second signal indicative of an amount of x-ray radiation detected from the specimen in response to the x-ray illumination beam; code for causing the computer to determine at least one specimen parameter value based on a fitting analysis of the first signal with the optical response model and a fitting analysis on the second signal with the x-ray response model; and code for causing the computer to store the at least one specimen parameter value. - View Dependent Claims (19, 20)
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Specification