Metrology diffraction signal adaptation for tool-to-tool matching
First Claim
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1. A method in integrated circuit astrology for adapting a metrology system to work with diverse astrology devices, the method comprising:
- measuring a set of sites on a wafer utilizing a first metrology device, the measurement generating a first set of diffraction signals, the first astrology device having identifying specifications;
measuring the set of sites on the wafer utilizing a second metrology device, the measurement generating a second set of diffraction signals, the second metrology device having identifying specifications;
calculating differences between each signal of the first set of diffraction signals and the corresponding signal of the second set of diffraction signals; and
determining a signal adjustment vector from the calculated differences, the signal adjustment vector configured to enable metrology data created for the first metrology device to be used in the second astrology device.
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Abstract
A method and system in integrated circuit metrology for adapting a metrology system to work with diverse metrology devices. One embodiment is a method and system for generating signal adjustment data to adapt measured diffraction signals to enable use of a library of diffraction signals and structure profiles created for a different metrology device. Another embodiment is the creation and use of a data store of diffraction adjustment vectors and metrology device specifications relative to a reference device specification.
53 Citations
28 Claims
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1. A method in integrated circuit astrology for adapting a metrology system to work with diverse astrology devices, the method comprising:
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measuring a set of sites on a wafer utilizing a first metrology device, the measurement generating a first set of diffraction signals, the first astrology device having identifying specifications;
measuring the set of sites on the wafer utilizing a second metrology device, the measurement generating a second set of diffraction signals, the second metrology device having identifying specifications;
calculating differences between each signal of the first set of diffraction signals and the corresponding signal of the second set of diffraction signals; and
determining a signal adjustment vector from the calculated differences, the signal adjustment vector configured to enable metrology data created for the first metrology device to be used in the second astrology device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
measuring a diffraction signal off an integrated circuit structure using the second metrology device, the measurement generating a measured structure diffraction signal;
calculating an adjusted diffraction signal utilizing the measured structure diffraction signal and the signal adjustment vector;
selecting a best match of the adjusted diffraction signal compared to diffraction signals in the library of diffraction signals and corresponding profile dara, the library created for the first metrology device; and
accessing the profile data corresponding to the selected best match library diffraction signal.
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5. The method of claim 4 wherein the first and second metrology devices are ellipsometers and wherein each of the first and second set of diffraction signals comprises tangent (Ψ
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) diffraction data.
- ) and cosine (Δ
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6. The method of claim 4 wherein the first and second metrology devices are reflectometers and wherein each of the first and second set of diffraction signals comprises intensity diffraction data.
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7. The method of claim 1 wherein determining the signal adjustment vector comprises performing a mathematical algorithm to compute the values of elements of the signal adjustment vector.
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8. The method of claim 7 wherein the mathematical algorithm used to compute the element values is a clustering algorithm.
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9. The method of claim 1 further comprising:
storing the signal adjustment vector and identifying specifications of the first and second metrology device.
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10. A method in integrated circuit metrology for adapting a metrology system to work with diverse metrology devices, the method comprising:
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measuring a set of sites on a wafer utilizing a first metrology device, the measurement generating a first set of diffraction signals, the first metrology device having identifying specifications;
measuring the set of sites on the wafer utilizing one or more second metrology devices, each measurement generating a second set of diffraction signals, each second metrology device having identifying specifications;
calculating differences between each signal of the first set of diffraction signals and the corresponding signal of the second sets of diffraction signals;
determining a signal adjustment vectors from the calculated differences, each signal adjustment vector configured to enable metrology data created for the first metrology device to be used in a corresponding second metrology device; and
storing data elements comprising the identifying specifications of the first metrology device, identifying specifications of the second metrology device, and the associated signal adjustment vector. - View Dependent Claims (11)
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12. A system for adapting an integrated circuit metrology system to work with a plurality of metrology devices, the method comprising:
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a first metrology device configured to generate a first set of diffraction signals off a set of structures in a wafer, the first metrology device having identifying specifications;
a second metrology device configured to generate a second set of diffraction signals off the set of structures in the wafer, the second metrology device having identifying specifications; and
an estimator configured to calculate differences between each signal of the first set of diffraction signals and the corresponding signal of the second set of diffraction signals and configured to determine a signal adjustment vector from the calculated differences, wherein the signal adjustment vector enables metrology signal data created for use in the first metrology device to be used in the second metrology device. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
a profile library configured to contain diffraction signals and associated profile data; and
a profile application server configured to process measured diffraction signals and select a best match of to measured diffraction signal compared to the diffraction signal of the profile library.
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16. The system of claim 15 further comprising:
a data store coupled to the profile application server, the data store configured to store one or more signal adjustment vectors and metrology tool identifying specifications.
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17. The system of claim 16 wherein the data store is accessible via a network connection.
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18. The system of claim 16 wherein the estimator uses averaging to determine the signal adjustment vectors.
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19. The system of claim 16 wherein the estimator uses a statistical averaging algorithm to determine the signal adjustment vectors.
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20. The system of claim 16 wherein the estimator uses clustering algorithm to determine the signal adjustment vectors.
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21. A system for storing integrated circuit metrology signal adjustment data and responding to request for signal adaptation, the system comprising:
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a query device configured to send a query including identifying information about a metrology device and identifying information about a library of diffraction signals and associated profiles;
a signal adjustment server coupled to the query device and configured to process the query and configured to format and transmit a response to the query device; and
a data store couple to the signal adjustment server and configured to store signal adjustment data, identifying information about metrology devices, and identifying information about a library of diffraction signals and associated profiles, wherein the signal adjustment data includes one or more signal adjustment vectors, wherein each signal adjustment vector is determined from calculating differences between a diffraction signal generated by measuring a site on a wafer utilizing a first metrology device and a diffraction signal generated by measuring the site on the wafer utilizing a second metrology device. - View Dependent Claims (22, 23, 24, 25)
a fabrication system coupled to the query device, the fabrication system including a lithography unit and/or an etch unit.
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26. A computer-readable storage medium containing computer executable code to adapt a metrology system to work with diverse metrology devices by instructing a computer to operate as follows:
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measuring a set of sites on a wafer utilizing a first metrology device, the measurement generating a first set of diffraction signals, the first metrology device having identifying specifications;
measuring the set of sites on the wafer utilizing a second metrology device, the measurement generating a second set of diffraction signals, the second metrology device having identifying specifications;
calculating differences between each signal of the first set of diffraction signals and the corresponding signal of the second set diffraction signals; and
determining a signal adjustment vector from the calculated differences, the signal adjustment vector configured to enable metrology data created for the first metrology device to be used in the second metrology device.
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27. A computer-readable storage medium containing computer executable code to adapt a metrology system to work with diverse metrology devices by instructing a computer to operate as follows:
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measuring a set of sites on a wafer utilizing a first metrology device, the measurement generating a first set of diffraction signals, the first metrology device having identifying specifications;
measuring the set of sites on the wafer utilizing one or we second metrology devices, each measurement generating a second set of diffraction signals, each second metrology device having identifying specifications;
calculating differences between each signal of the first set of diffraction signals and the corresponding signal of the second sets of diffraction signals;
determining a signal adjustment vectors from the calculated differences, each signal adjustment vector configured to enable metrology data created for the first metrology device to be used in a corresponding second metrology device; and
storing date elements comprising the identifying specifications of the first metrology device, identifying specifications of the second metrology device, and the associated signal adjustment vector.
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28. A computer-readable storage medium containing stored data including:
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identifying information for a primary metrology device;
identifying information for one or more secondary metrology devices;
identifying information for a library of diffraction signals and associated profiles; and
one or more signal adjustment vectors, each signal adjustment vector determined from calculating differences between a diffraction signal generated by measuring a site on a wafer utilizing the primary metrology device and a diffraction signal generated by measuring the site on the wafer utilizing on of the one or more secondary metrology devices, wherein each signal adjustment vector is configured to adapt diffraction signals measured using the secondary metrology device to be operative with the identified library of diffraction signals and associated profiles.
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Specification