Method for in-situ monitoring of patterned substrate processing using reflectometry.
First Claim
1. A method of determining a parameter of interest during fabrication of a patterned substrate, comprising:
- illuminating at least a portion of the patterned substrate with a normal incident light beam;
obtaining a measured net reflectance spectrum of the portion of the patterned substrate from a normal reflected light beam;
calculating a modeled net reflectance spectrum of the portion of the patterned substrate as a weighted incoherent sum of reflectances from n≧
1 different regions constituting the portion of the patterned substrate, wherein the reflectance of each of the n different regions is a weighted coherent sum of reflected fields from k≧
1 laterally-distinct areas constituting the region; and
determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum.
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Abstract
A method of determining a parameter of interest during fabrication of a patterned substrate includes illuminating at least a portion of the patterned substrate with a normal incident light beam, obtaining a measured net reflectance spectrum of the portion of the patterned substrate from a normal reflected light beam, calculating a modeled net reflectance spectrum of the portion of the patterned substrate, and determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum. The modeled net reflectance spectrum is calculated as a weighted incoherent sum of reflectances from n≧1 different regions constituting the portion of the patterned substrate, wherein the reflectance of each of the n different regions is a weighted coherent sum of reflected fields from k≧1 laterally-distinct areas constituting the region.
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Citations
22 Claims
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1. A method of determining a parameter of interest during fabrication of a patterned substrate, comprising:
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illuminating at least a portion of the patterned substrate with a normal incident light beam; obtaining a measured net reflectance spectrum of the portion of the patterned substrate from a normal reflected light beam; calculating a modeled net reflectance spectrum of the portion of the patterned substrate as a weighted incoherent sum of reflectances from n≧
1 different regions constituting the portion of the patterned substrate, wherein the reflectance of each of the n different regions is a weighted coherent sum of reflected fields from k≧
1 laterally-distinct areas constituting the region; anddetermining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 21, 22)
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10. A process control method for fabrication of a patterned substrate. comprising:
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illuminating at least a portion of the patterned substrate with a normal incident light beam while processing the patterned substrate; obtaining a measured reflectance spectrum of the portion of the patterned substrate over a range of wavelengths; calculating a modeled reflectance spectrum of the portion of the patterned substrate over a range of wavelengths as a weighted incoherent sum of reflectances from n≧
1 different regions constituting the patterned substrate, wherein the reflectance of each of the n different regions is a weighted coherent sum of reflected fields from k≧
1 laterally-distinct areas constituting the region;determining a set of parameters that provides a close match between the measured reflectance spectrum and the modeled reflectance spectrum; deriving a parameter of interest from the set of parameters; and signaling an endpoint in the processing of the patterned substrate if the value of the parameter of interest satisfies a predetermined endpoint criterion. - View Dependent Claims (11, 12, 13)
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14. A method for determining a vertical dimension of a feature on a patterned substrate, comprising:
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illuminating at least a portion of the patterned substrate including the feature with a normal incident light beam; obtaining a measured net reflectance spectrum of the portion of the patterned substrate from a normal reflected light beam; calculating a modeled net reflectance spectrum of the portion of the patterned substrate as a weighted incoherent sum of reflectances from n≧
1 different regions constituting the portion of the patterned substrate, wherein the reflectance of each of the n different regions is a weighted coherent sum of reflected fields from k≧
1 laterally-distinct areas constituting the region;determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum; and extracting the vertical dimension of the feature from the set of parameters. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification