Reticle inspection using near-field recovery
First Claim
1. A computer-implemented method for detecting defects on a reticle, comprising:
- separating a pattern included in an inspection area on the reticle into two or more segments;
separately comparing the two or more segments to predetermined segments included in a data structure, wherein the data structure comprises pairs of the predetermined segments of a reticle pattern and corresponding near-field data;
assigning near-field data to at least one of the two or more segments based on one of the predetermined segments to which the at least one of the two or more segments is most similar;
generating near-field data for the inspection area based on the assigned near-field data;
simulating an image, based on the generated near-field data, of the inspection area that would be formed by a detector of a reticle inspection system;
acquiring an actual image of the inspection area on a physical version of the reticle generated by the detector; and
detecting defects on the reticle by comparing the simulated image to the actual image, wherein said separating, separately comparing, assigning, generating, simulating, acquiring, and detecting are performed with one or more computer systems.
1 Assignment
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Accused Products
Abstract
Systems and methods for detecting defects on a reticle are provided. The embodiments include generating and/or using a data structure that includes pairs of predetermined segments of a reticle pattern and corresponding near-field data. The near-field data for the predetermined segments may be determined by regression based on actual image(s) of a reticle generated by a detector of a reticle inspection system. Inspecting a reticle may then include separately comparing two or more segments of a pattern included in an inspection area on the reticle to the predetermined segments and assigning near-field data to at least one of the segments based on the predetermined segment to which it is most similar. The assigned near-field data can then be used to simulate an image that would be formed for the reticle by the detector, which can be compared to an actual image generated by the detector for defect detection.
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Citations
41 Claims
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1. A computer-implemented method for detecting defects on a reticle, comprising:
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separating a pattern included in an inspection area on the reticle into two or more segments; separately comparing the two or more segments to predetermined segments included in a data structure, wherein the data structure comprises pairs of the predetermined segments of a reticle pattern and corresponding near-field data; assigning near-field data to at least one of the two or more segments based on one of the predetermined segments to which the at least one of the two or more segments is most similar; generating near-field data for the inspection area based on the assigned near-field data; simulating an image, based on the generated near-field data, of the inspection area that would be formed by a detector of a reticle inspection system; acquiring an actual image of the inspection area on a physical version of the reticle generated by the detector; and detecting defects on the reticle by comparing the simulated image to the actual image, wherein said separating, separately comparing, assigning, generating, simulating, acquiring, and detecting are performed with one or more computer systems. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A computer-implemented method for setting up a reticle inspection process, comprising:
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separating pattern information for a reticle into predetermined segments; determining near-field data for the predetermined segments based on one or more actual images of the reticle acquired by a detector of a reticle inspection system, wherein the near-field data for the predetermined segments is determined by regression based on the one or more actual images of the reticle; generating a data structure that comprises pairs of the predetermined segments and the near-field data corresponding to the predetermined segments; and setting up the reticle inspection process by incorporating information for the generated data structure in a recipe for the reticle inspection process such that during the reticle inspection process, two or more segments in an inspection area on the reticle or another reticle are compared to the predetermined segments and the near-field data for one of the predetermined segments to which at least one of the two or more segments is most similar is assigned to the at least one of the two or more segments, wherein the separating, determining, generating, and setting up steps are performed by one or more computer systems.
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21. A computer-implemented method for setting up a reticle inspection process, comprising:
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separating pattern information for a reticle into predetermined segments; determining near-field data for the predetermined segments by numerically solving equations that govern electromagnetic fields for the predetermined segments; generating a data structure that comprises pairs of the predetermined segments and the near-field data corresponding to the predetermined segments; and setting up the reticle inspection process by incorporating information for the generated data structure in a recipe for the reticle inspection process such that during the reticle inspection process, two or more segments in an inspection area on the reticle or another reticle are compared to the predetermined segments and the near-field data for one of the predetermined segments to which at least one of the two or more segments is most similar is assigned to the at least one of the two or more segments, wherein the separating, determining, generating, and setting up steps are performed by one or more computer systems.
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22. A non-transitory computer-readable medium, storing program instructions executable on a computer system for performing a computer-implemented method for detecting defects on a reticle, wherein the computer-implemented method comprises:
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separating a pattern included in an inspection area on the reticle into two or more segments; separately comparing the two or more segments to predetermined segments included in a data structure, wherein the data structure comprises pairs of the predetermined segments of a reticle pattern and corresponding near-field data; assigning near-field data to at least one of the two or more segments based on one of the predetermined segments to which the at least one of the two or more segments is most similar; generating near-field data for the inspection area based on the assigned near-field data; simulating an image, based on the generated near-field data, of the inspection area that would be formed by a detector of a reticle inspection system; acquiring an actual image of the inspection area on a physical version of the reticle generated by the detector; and detecting defects on the reticle by comparing the simulated image to the actual image.
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23. A system configured to detect defects on a reticle, comprising:
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a reticle inspection subsystem comprising a detector configured to generate an actual image of an inspection area on a physical version of the reticle; and one or more computer subsystems configured for; separating a pattern included in the inspection area into two or more segments; separately comparing the two or more segments to predetermined segments included in a data structure, wherein the data structure comprises pairs of the predetermined segments of a reticle pattern and corresponding near-field data; assigning near-field data to at least one of the two or more segments based on one of the predetermined segments to which the at least one of the two or more segments is most similar; generating near-field data for the inspection area based on the assigned near-field data; simulating an image, based on the generated near-field data, of the inspection area that would be formed by the detector; acquiring the actual image from the detector; and detecting defects on the reticle by comparing the simulated image to the actual image. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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Specification