Detecting defects on a wafer with run time use of design data
First Claim
1. A method for detecting defects on a wafer, comprising:
- creating a database for a design for a wafer, wherein said creating comprises assigning values to different portions of the design based on patterns in the different portions of the design and storing the assigned values in the database, and wherein the different portions of the design having substantially the same patterns are assigned the same values in the database;
scanning the wafer with a wafer inspection system, wherein one or more detectors of the wafer inspection system generate output for the wafer during the scanning,while the scanning is being performed, searching the database for patterns in the output, wherein the searching is synchronized with generation of the output for the wafer by the wafer inspection system;
determining values for different portions of the output as the values assigned to the different portions of the design having the patterns that substantially match the patterns in the output, anddetecting defects on the wafer by applying one or more defect detection algorithms to the output based on the values assigned to the different portions of the output, wherein creating the database, searching the database, determining the values, and detecting the defects are performed with one or more computer systems, and wherein applying the one or more defect detection algorithms comprises;
determining a statistic for the different portions of the output;
detecting defects in the different portions of the output based on the statistics and for one of the different portions of the output in which one of the defects was detected;
generating a first comparing result by comparing the statistic for the one different portion to the statistics for one or more of the different portions of the output generated within the same die as the one different portion and having the same assigned values as the one different portion;
generating a second comparing result by comparing the statistic for the one different portion to the statistics for one or more other of the different portions of the output generated in one or more dies other than the die in which the one different portion was generated and having the same assigned values as the one different portion; and
determining a defect type for the one of the defects based on the first and second comparing results in combination.
1 Assignment
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Accused Products
Abstract
Methods and systems for detecting defects on a wafer are provided. One method includes creating a searchable database for a design for a wafer, which includes assigning values to different portions of the design based on patterns in the different portions of the design and storing the assigned values in the searchable database. Different portions of the design having substantially the same patterns are assigned the same values in the searchable database. The searchable database is configured such that searching of the database can be synchronized with generation of output for the wafer by one or more detectors of a wafer inspection system. Therefore, as the wafer is being scanned, design information for the output can be determined as fast as the output is generated, which enables multiple, desirable design based inspection capabilities.
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Citations
94 Claims
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1. A method for detecting defects on a wafer, comprising:
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creating a database for a design for a wafer, wherein said creating comprises assigning values to different portions of the design based on patterns in the different portions of the design and storing the assigned values in the database, and wherein the different portions of the design having substantially the same patterns are assigned the same values in the database; scanning the wafer with a wafer inspection system, wherein one or more detectors of the wafer inspection system generate output for the wafer during the scanning, while the scanning is being performed, searching the database for patterns in the output, wherein the searching is synchronized with generation of the output for the wafer by the wafer inspection system; determining values for different portions of the output as the values assigned to the different portions of the design having the patterns that substantially match the patterns in the output, and detecting defects on the wafer by applying one or more defect detection algorithms to the output based on the values assigned to the different portions of the output, wherein creating the database, searching the database, determining the values, and detecting the defects are performed with one or more computer systems, and wherein applying the one or more defect detection algorithms comprises; determining a statistic for the different portions of the output; detecting defects in the different portions of the output based on the statistics and for one of the different portions of the output in which one of the defects was detected; generating a first comparing result by comparing the statistic for the one different portion to the statistics for one or more of the different portions of the output generated within the same die as the one different portion and having the same assigned values as the one different portion; generating a second comparing result by comparing the statistic for the one different portion to the statistics for one or more other of the different portions of the output generated in one or more dies other than the die in which the one different portion was generated and having the same assigned values as the one different portion; and determining a defect type for the one of the defects based on the first and second comparing results in combination. - View Dependent Claims (2, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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3. 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 wafer, wherein the computer-implemented method comprises:
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creating a database for a design for a wafer, wherein said creating comprises assigning values to different portions of the design based on patterns in the different portions of the design and storing the assigned values in the database, and wherein the different portions of the design having substantially the same patterns are assigned the same values in the database; scanning the wafer with a wafer inspection system, wherein one or more detectors of the wafer inspection system generate output for the wafer during the scanning, while the scanning is being performed, searching the database for patterns in the output, wherein the searching is synchronized with generation of the output for the wafer by the wafer inspection system; determining values for different portions of the output as the values assigned to the different portions of the design having the patterns that substantially match the patterns in the output, and detecting defects on the wafer by applying one or more defect detection algorithms to the output based on the values assigned to the different portions of the output, wherein applying the one or more defect detection algorithms comprises; determining a statistic for the different portions of the output; detecting defects in the different portions of the output based on the statistics; and for one of the different portions of the output in which one of the defects was detected; generating a first comparing result by comparing the statistic for the one different portion to the statistics for one or more of the different portions of the output generated within the same die as the one different portion and having the same assigned values as the one different portion; generating a second comparing result by comparing the statistic for the one different portion to the statistics for one or more other of the different portions of the output generated in one or more dies other than the die in which the one different portion was generated and having the same assigned values as the one different portion; and determining a defect type for the one of the defects based on the first and second comparing results in combination.
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4. 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 wafer, wherein the computer-implemented method comprises:
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creating a database for a design for a wafer, wherein said creating comprises assigning values to different portions of the design based on patterns in the different portions of the design and storing the assigned values in the database, and wherein the different portions of the design having substantially the same patterns are assigned the same values in the database; scanning the wafer with a wafer inspection system, wherein one or more detectors of the wafer inspection system generate output for the wafer during the scanning; while the scanning is being performed, searching the database for patterns in the output, wherein the searching is synchronized with generation of the output for the wafer by the wafer inspection system; determining values for different portions of the output as the values assigned to the different portions of the design having the patterns that substantially match the patterns in the output; and detecting defects on the wafer by applying one or more defect detection algorithms to the output based on the values assigned to the different portions of the output, and wherein applying the one or more defect detection algorithms comprises; comparing the output generated at corresponding locations in different dies; identifying candidate defects based on results of the comparing; and for one of the candidate defects; determining a detection confidence based on two or more of the different portions of the output having the same assigned values as the different portion of the output in which the one candidate defect was detected; rejecting or accepting the one candidate defect as an actual defect based on the detection confidence; and altering one or more parameters of scanning the wafer and detecting the defects based on whether the one candidate defect is rejected or accepted.
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26. A system configured to detect defects on a wafer, comprising:
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one or more computer subsystems configured for creating a database for a design for a wafer, wherein said creating comprises assigning values to different portions of the design based on patterns in the different portions of the design and storing the assigned values in the database, and wherein the different portions of the design having substantially the same patterns are assigned the same values in the database; and an optical subsystem configured for scanning the wafer, wherein one or more detectors of the optical subsystem generate output for the wafer during the scanning, and wherein the one or more computer subsystems are further configured for; while the scanning is being performed, searching the database for patterns in the output, wherein the searching is synchronized with generation of the output for the wafer by the optical subsystem; determining values for different portions of the output as the values assigned to the different portions of the design having the patterns that substantially match the patterns in the output; and detecting defects on the wafer by applying one or more defect detection algorithms to the output based on the values assigned to the different portions of the output, wherein applying the one or more defect detection algorithms comprises; determining a statistic for the different of the output; detecting defects in the different portions of the output based on the statistics; and for one of the different portions of the output in which one of the defects was detected; generating a first comparing result by comparing the statistic for the one different portion to the statistics for one or more of the different portions of the output generated within the same die as the one different portion and having the same assigned values as the one different portion; generating a second comparing result by comparing the statistic for the one different portion to the statistics for one or more other of the different portions of the output generated in one or more dies other than the die in which the one different portion was generated and having the same assigned values as the one different portion; and determining a defect type for the one of the defects based on the first and second comparing results in combination. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A method for detecting defects on a water, comprising:
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creating a database for a design for a wafer, wherein said creating comprises assigning values to different portions of the design based on patterns in the different portions of the design and storing the assigned values in the database, and wherein the different portions of the design having substantially the same patterns are assigned the same values in the database; scanning the wafer with a wafer inspection system, wherein one or more detectors of the wafer inspection system generate output for the wafer during the scanning; while the scanning is being performed, searching the database for patterns in the output, wherein the searching is synchronized with generation of the output for the wafer by the wafer inspection system; determining values for different portions of the output as the values assigned to the different portions of the design having the patterns that substantially match the patterns in the output; and detecting defects on the wafer by applying one or more defect detection algorithms to the output based on the values assigned to the different portions of the output, wherein creating the database, searching the database, determining the values, and detecting the defects are performed with one or more computer systems, and wherein applying the one or more defect detection algorithms comprises; comparing the output generated at corresponding locations in different dies; identifying candidate defects based on results of the comparing; and for one of the candidate defects; determining a detection confidence based on two or more of the different portions of the output having the same assigned values as the different portion of the output in which the one candidate defect was detected; rejecting or accepting the one candidate defect as an actual defect based on the detection confidence; and altering one or more parameters of scanning the wafer and detecting the defects based on whether the one candidate defect is rejected or accepted. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71)
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72. A system configured to detect defects on a wafer, comprising:
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one or more computer subsystems configured for creating a database for a design for a wafer, wherein said creating comprises assigning values to different portions of the design based on patterns in the different portions of the design and storing the assigned values in the database, and wherein the different portions of the design having substantially the same patterns are assigned the same values in the database; and an optical subsystem configured for scanning the wafer, wherein one or more detectors of the optical subsystem generate output for the wafer during the scanning, and wherein the one or more computer subsystems are further configured for; while the scanning is being performed, searching the database for patterns in the output, wherein the searching is synchronized with generation of the output for the wafer by the optical subsystem; determining values for different portions of the output as the values assigned to the different portions of the design having the patterns that substantially match the patterns in the output; and detecting defects on the wafer by applying one or more defect detection algorithms to the output based on the values assigned to the different portions of the output, and wherein applying the one or more defect detection algorithms comprises; comparing the output generated at corresponding locations in different dies; identifying candidate defects based on results of the comparing; and for one of the candidate defects; determining a detection confidence based on two or more of the different portions of the output having the same assigned values as the different portion of the output in which the one candidate defect was detected; rejecting or accepting the one candidate defect as an actual defect based on the detection confidence; and altering one or more parameters of scanning the wafer and detecting the defects based on whether the one candidate defect is rejected or accepted. - View Dependent Claims (73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94)
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Specification