Interferometer and method for measuring characteristics of optically unresolved surface features
AssigneeZygo Corporation
InventorsPeter De Groot, Michael J Darwin, Robert T Stoner, Gregg M. Gallatin, Xavier Colonna De Lega
Life of this patent
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Abstract
Disclosed is an interferometry analysis method that includes comparing information derivable from multiple interferometry signals corresponding to different surface locations of a test object to information corresponding to multiple models of the test object, wherein the multiple models are parameterized by a series of characteristics that relate to one or more under-resolved lateral features of the test object; and outputting information about the under-resolved surface feature based on the comparison.
Claims56
A method comprising:
- comparing information derivable from multiple interferometry signals corresponding to different surface locations of a test object to information corresponding to multiple models of the test object, wherein the multiple models are parameterized by a series of characteristics that relate to one or more under-resolved lateral features of the test object;
- and
- outputting information about the under-resolved surface feature based on the comparison.
A method for determining one or more spatial properties of a grating structure on a test object, wherein the grating structure comprises line elements having widths smaller than 400 nm so that the line elements are not fully resolved by an interference microscope, the method comprising:
- determining an apparent height for a collection of at least some of the grating lines from interference signals at different locations of the test object measured by the interference microscope;
- providing an expected response for the interference microscope for different possible values for the properties of the grating structure, wherein the expected response includes contributions from under-resolved line elements of the grating structure;
- comparing the apparent height to the expected response for the different possible values to determine information about the spatial properties of a grating structure;
- and
- outputting the determined information about the spatial properties of the grating structure.
A method comprising:
- determining one or more apparent properties of a test surface from interferometry signals produced by an interferometry system;
- comparing the apparent properties determined from the interferometry signals to an expected response for the interferometry system for different possible values for one or more under-resolved features of the test surface;
- and
- outputting information about the one or more under-resolved features of the test surface based on the comparison.
Apparatus comprising:
- a computer readable medium having a program that causes a processor in a computer to compare information derivable from multiple interferometry signals corresponding to different surface locations of a test object to information corresponding to multiple models of the test object, wherein the multiple models are parameterized by a series of characteristics that relate to one or more under-resolved lateral features of the test object, and output information about the under-resolved surface feature based on the comparison.
Apparatus comprising:
- an interferometry system configured to produce multiple interferometry signals corresponding to different surface locations of a test object;
- and
- an electronic processor coupled to the interferometry system to receive the interferometry signals and programmed to compare information derivable from the multiple interferometry signals to information corresponding to multiple models of the test object, wherein the multiple models are parameterized by a series of characteristics that relate to one or more under-resolved lateral features of the test object, and output information about the under-resolved surface feature based on the comparison.
An apparatus for determining one or more spatial properties of a grating structure on a test object, wherein the grating structure comprises line elements having widths smaller than 400 nm so that the line elements are not hilly resolved by an interference microscope, the apparatus comprising:
- a computer readable medium having a program that causes a processor in a computer to:
- 1) determine an apparent height for a collection of at least some of the grating lines from interference signals at different locations of the test object measured by the interference microscope;
- 2) provide an expected response for the interference microscope for different possible values for the properties of the grating structure, wherein the expected response includes contributions from under-resolved line elements of the grating structure;
- 3) compare the apparent height to the expected response for the different possible values to determine information about the spatial properties of a grating structure;
- and 4) output the determined information about the, spatial properties of the grating structure.
An apparatus for determining one or more spatial properties of a grating structure on a test object, wherein the grating structure comprises line elements having widths smaller than 400 nm so that the line elements are not fully resolved by an interference microscope, the apparatus, comprising:
- the interference microscope;
- and
- an electronic processor coupled to the interference microscope and programmed to:
- 1) determine an apparent height for a collection of at least some of the grating lines from interference signals at different locations of the test object measured by the interference microscope;
- 2) provide an expected response for the interference microscope for different possible values for the properties of the grating structure, wherein the expected response includes contributions from under-resolved line elements of the grating structure;
- 3) compare the apparent height to the expected response for the different possible values to determine information about the spatial properties of a grating structure;
- and 4) output the determined information about the spatial properties of the grating structure.
Apparatus comprising:
- a computer readable medium having a program that causes a processor in a computer to:
- 1) determine one or more apparent properties of a test surface from interferometry signals produced by an interferometry system;
- 2)compare the apparent properties determined from the interferometry signals to an expected response for the interferometry system for different possible values of one or more under-resolved features of the test surface;
- and 3) output information about the one or more under-resolved features of the test surface based on the comparison.
Apparatus comprising:
- an interferometry system configured to produce multiple interferometry signals corresponding to different surface locations of a test object;
- and
- an electronic processor coupled to the interferometry system to receive the interferometry signals and programmed to:
- 1) determine one or more apparent properties of a test surface from the interferometry signals;
- 2) compare the apparent properties determined from the interferometry signals to an expected response for the interferometry system for different possible values of one or more under-resolved features of the test surface;
- and 3) output information about the one or more under-resolved features of the test surface based on the comparison.
Dependencies are inferred from the claim text.