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Model-based scanner tuning systems and methods

  • US 8,874,423 B2
  • Filed: 10/28/2013
  • Issued: 10/28/2014
  • Est. Priority Date: 06/03/2008
  • Status: Active Grant
First Claim
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1. A method implemented by a computer, the method being for tuning a lithographic apparatus using a corresponding differential model that predicts changes in imaging behavior due to changes between two or more lithographic apparatuses, the method comprising:

  • maintaining a lithographic process model characterizing imaging behavior of a lithographic process for a given layer of a wafer using one of the lithographic apparatuses, given particular values for a set of tunable parameters on the one lithographic apparatus;

    generating a simulated wafer contour in the given layer using a design layout and the lithographic process model based on the particular values of the set of tunable parameters;

    identifying discrepancies in the simulated wafer contour against a reference corresponding to the particular values of the set of tunable parameters and a different one of the lithographic apparatuses;

    quantifying the discrepancies with a cost function; and

    performing iterations of the generating and identifying steps to minimize the cost function and obtain calibrated parameters of the differential model, wherein each iteration uses a different reference corresponding to a different one of the lithographic apparatuses,wherein one or more of the maintaining, generating, identifying, quantifying and performing steps are implemented by the computer.

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