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Process margin using discrete assist features

  • US 7,749,662 B2
  • Filed: 10/07/2005
  • Issued: 07/06/2010
  • Est. Priority Date: 10/07/2005
  • Status: Active Grant
First Claim
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1. A method of improving a process margin of a lithographic imaging system, comprising:

  • identifying a semi-isolated pattern feature on a mask as a potential limiting factor to a process margin for a lithographic imaging technique;

    determining a resolution threshold for the imaging technique;

    determining a maximum size threshold for discrete scatterbar segments based at least in part on the determined resolution threshold for the imaging system and a known amount line-end pull back that occurs at the resolution threshold; and

    mitigating a resist residue by placing a discrete scatterbar comprising more than one discrete sub-resolution scatterbar segment near the semi-isolated mask featureConstructing the more than one discrete scatterbar segments with a pitch outside of a range of pitches that can be resolved perpendicular to an axis of a dipole illumination source, and within a range of pitches that can be resolved parallel to the axis of the dipole illumination source, and orienting the discrete scatterbar perpendicular to the axis to mitigate discrete scatterbar segments resolution by the imaging system.

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