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Method for improved lithographic patterning in a semiconductor fabrication process

  • US 5,340,700 A
  • Filed: 11/03/1993
  • Issued: 08/23/1994
  • Est. Priority Date: 04/06/1992
  • Status: Expired due to Term
First Claim
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1. In a method for lithographically transferring a pattern from a mask into a radiation-sensitive material deposited over a semiconductor substrate utilizing an imaging tool, said pattern including a feature having first and second edges, each of said first and second edges having associated edge gradients, said first and second edges being spaced in close proximity to one another such that said associated edge gradients interact causing said feature to be distorted in said radiation-sensitive material, an improved method comprising the steps of:

  • a) providing a first rectilinear mask image segment, said first rectilinear mask image segment having a first set of mask edges, all opposing mask edges in said first set of mask edges being spaced a distance greater than the Rayleigh limit of said imaging tool and greater than the distance between said first and second edges, a single edge from said first set of mask edges corresponding to said first edge;

    b) exposing said first rectilinear mask image segment with radiation using said imaging tool such that said single edge from said first set of mask edges produces a first pattern edge gradient defining said first edge of said two-dimensional feature in said material;

    c) providing a second rectilinear mask image segment, said second rectilinear mask image segment having a second set of mask edges, all opposing mask edges in said second set of mask edges being spaced a distance greater than said Rayleigh limit of said imaging tool and greater than said distance between said first and second edges, a single edge from said second set of mask edges corresponding to said second edge;

    d) exposing said second rectilinear mask image segment with radiation using said imaging tool such that said single edge from said second set of mask edges produces a second pattern edge gradient defining said second edge of said two-dimensional feature in said material, wherein said first and second edges are separated by distance which is less than or equal to the Rayleigh limit of said imaging tool and wherein said second pattern edge gradient and said first pattern edge gradient do not interact;

    e) developing said radiation-sensitive material, thereby reproducing said feature on said substrate.

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