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Methods for improved monitor and control of lithography processes

  • US 9,188,974 B1
  • Filed: 07/17/2011
  • Issued: 11/17/2015
  • Est. Priority Date: 02/13/2004
  • Status: Active Grant
First Claim
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1. A computer-implemented method, comprising:

  • controlling one or more parameters of features within an entire printed area on a product wafer using a limited number of wafer measurements performed on the product wafer or another wafer, wherein the wafer measurements comprise one or more parameters of horizontal features and vertical features printed on the product wafer or the other wafer using a lithoaraphy system;

    determining exposure conditions applied to the product wafer or the other wafer based on the wafer measurements;

    predicting one or more parameters of one or more feature types printed on the product wafer using a tuned simulation model with the exposure conditions and design data for the product wafer, wherein the one or more feature types comprise at least one feature type on which the wafer measurements were not performed;

    determining errors in performance of a lens of the lithography system across a field of the lens based on the wafer measurements and separating the errors into correctable and non-correctable errors across the field, wherein the errors comprise dose errors, focus errors, or dose and focus errors; and

    determining astigmatism errors in the lens using the errors, wherein said controlling, said determining the exposure conditions, said predicting, said determining the errors, and said determining the astigmatism errors are performed by a computer having one or more processors executing instructions from a memory medium.

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