MULTI-MODEL METROLOGY
First Claim
1. A method of characterizing a plurality of structures of interest on a sample, the method comprising:
- generating a plurality of models that are different from each other in that they have different combinations of floating and fixed critical parameters for outputting simulated spectra, wherein the models are generated as final models to determine different one or more critical parameters for unknown structures based on spectra collected from such unknown structures;
after generating the models and without generating another model, determining which one of the models best correlates with each critical parameter based on reference data that includes a plurality of known values for each of a plurality of critical parameters and corresponding known spectra; and
for spectra measured from an unknown structure using a metrology tool, selecting and using different ones of the models to determine different ones of the critical parameters of the unknown structure based on determining which one of the models best correlates with each critical parameter based on the reference data.
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Abstract
Disclosed are apparatus and methods for characterizing a plurality of structures of interest on a semiconductor wafer. A plurality of models having varying combinations of floating and fixed critical parameters and corresponding simulated spectra is generated. Each model is generated to determine one or more critical parameters for unknown structures based on spectra collected from such unknown structures. It is determined which one of the models best correlates with each critical parameter based on reference data that includes a plurality of known values for each of a plurality of critical parameters and corresponding known spectra. For spectra obtained from an unknown structure using a metrology tool, different ones of the models are selected and used to determine different ones of the critical parameters of the unknown structure based on determining which one of the models best correlates with each critical parameter based on the reference data.
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Citations
25 Claims
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1. A method of characterizing a plurality of structures of interest on a sample, the method comprising:
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generating a plurality of models that are different from each other in that they have different combinations of floating and fixed critical parameters for outputting simulated spectra, wherein the models are generated as final models to determine different one or more critical parameters for unknown structures based on spectra collected from such unknown structures; after generating the models and without generating another model, determining which one of the models best correlates with each critical parameter based on reference data that includes a plurality of known values for each of a plurality of critical parameters and corresponding known spectra; and for spectra measured from an unknown structure using a metrology tool, selecting and using different ones of the models to determine different ones of the critical parameters of the unknown structure based on determining which one of the models best correlates with each critical parameter based on the reference data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A semiconductor metrology tool, comprising:
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an illuminator for generating illumination; illumination optics for directing the illumination towards an unknown structure; collection optics for directing a plurality of spectra from the unknown structure to a sensor; the sensor for acquiring the plurality of spectra signals from the unknown structure; and a processor and memory configured for performing the following operations; generating a plurality of models that are different from each other in that they have different combinations of floating and fixed critical parameters for outputting simulated spectra, wherein the models are generated as final models to determine different one or more critical parameters for unknown structures based on spectra collected from such unknown structures; and after generating the models and without generating another model, determining which one of the models best correlates with each critical parameter based on reference data that includes a plurality of known values for each of a plurality of critical parameters and corresponding known spectra. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification