Determining a structural parameter and correcting an asymmetry property
First Claim
1. A method comprising:
- illuminating a structure, having an asymmetry property and comprising a sub-structure susceptible to process-induced asymmetry, with radiation with a plurality of illumination conditions, at a first location of a substrate;
determining a difference between measured asymmetry properties of the structure obtained with each of the plurality of illumination conditions;
calculating a differential dependence of a difference between modeled asymmetry properties simulated for illumination by each of the plurality of illumination conditions on a structural parameter representing process-induced asymmetry of the sub-structure; and
determining a value of the structural parameter using the determined difference and the calculated differential dependence.
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Abstract
A method of determining a structural parameter related to process-induced asymmetry, the method including: illuminating a structure, having an asymmetry property and a sub-structure susceptible to process-induced asymmetry, with radiation with a plurality of illumination conditions, at a first location of a substrate, determining a difference between measured asymmetry properties of the structure obtained with each of the plurality of illumination conditions, calculating a differential dependence of a difference between modeled asymmetry properties simulated for illumination by each of the plurality of illumination conditions on a structural parameter representing process-induced asymmetry of the sub-structure, and determining a value of the structural parameter using the determined difference and the calculated differential dependence.
63 Citations
23 Claims
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1. A method comprising:
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illuminating a structure, having an asymmetry property and comprising a sub-structure susceptible to process-induced asymmetry, with radiation with a plurality of illumination conditions, at a first location of a substrate; determining a difference between measured asymmetry properties of the structure obtained with each of the plurality of illumination conditions; calculating a differential dependence of a difference between modeled asymmetry properties simulated for illumination by each of the plurality of illumination conditions on a structural parameter representing process-induced asymmetry of the sub-structure; and determining a value of the structural parameter using the determined difference and the calculated differential dependence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus comprising:
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an illumination system configured to illuminate a structure, the structure having an asymmetry property and comprising a sub-structure susceptible to process-induced asymmetry, with radiation with a plurality of illumination conditions, at a first location of a substrate; and a processor configured to; determine a difference between measured asymmetry properties of the structure obtained with each of the plurality of illumination conditions; calculate a differential dependence of a difference between modeled asymmetry properties simulated for illumination by each of the plurality of illumination conditions on a structural parameter representing process-induced asymmetry of the sub-structure; and determine a value of the structural parameter using the determined difference and the calculated differential dependence. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A lithographic apparatus comprising:
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a projection system arranged to project a pattern image on to a substrate; and an inspection apparatus comprising; an illumination system configured to illuminate a structure, having an asymmetry property and comprising a sub-structure susceptible to process-induced asymmetry, with radiation with a plurality of illumination conditions, at a first location of a substrate; and a processor configured to; determine a difference between measured asymmetry properties of the structure obtained with each of the plurality of illumination conditions; calculate a differential dependence of a difference between modeled asymmetry properties simulated for illumination by each of the plurality of illumination conditions on a structural parameter representing process-induced asymmetry of the sub-structure; and determine a value of the structural parameter using the determined difference and the calculated differential dependence.
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Specification