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Method and apparatus for performing dark field double dipole lithography (DDL)

  • US 7,981,576 B2
  • Filed: 09/24/2010
  • Issued: 07/19/2011
  • Est. Priority Date: 04/06/2006
  • Status: Expired due to Fees
First Claim
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1. A method of generating complementary masks for use in a dark field double dipole imaging process, said method comprising the steps of:

  • identifying a target pattern having a plurality of features, said plurality of features comprising horizontal and vertical features;

    generating a horizontal dark field mask based on said target pattern, said horizontal dark field mask including low contrast features, said generation of said horizontal dark field mask comprising the steps of;

    optimizing the bias of said low contrast features contained in said horizontal dark field mask; and

    applying assist features to said horizontal dark field mask;

    generating a vertical dark field mask based on said target pattern, said vertical dark field mask containing low contrast features, said generation of said vertical dark field mask comprising the steps of;

    optimizing the bias of low contrast features contained in said vertical dark field mask; and

    applying assist features to said vertical dark field mask; and

    decomposing the target pattern into the horizontal dark field mask and the vertical dark field mask, the decomposing comprising;

    performing model-based optimization of both masks so as to optimize imaging performance criteria after double exposure of a feature in the target pattern during the dark field double dipole imaging process using both masks.

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