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Method for fabricating high circuit density, self-aligned metal linens to contact windows

  • US 5,143,820 A
  • Filed: 07/11/1991
  • Issued: 09/01/1992
  • Est. Priority Date: 10/31/1989
  • Status: Expired due to Fees
First Claim
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1. A method for fabricating a patterned conductive layer self-aligned to underlying contact windows in a dielectric layer on a substrate comprising the steps of:

  • forming a photosensitive layer over said dielectric layer, said photosensitive layer having full height areas, partial height areas and no height areas over said dielectric layer, wherein said no height areas and said partial height areas are aligned to each other;

    in a first etching step, selectively etching said dielectric layer in said no height areas where said photosensitive layer is substantially totally removed to form contact windows which at least partially penetrate said dielectric layer;

    in a second etching step, selectively etching to remove said partial height areas of photosensitive layer;

    in a third etching step, etching said dielectric layer in said partial height areas to a predetermined depth to form channels for said patterned conductive layer, and in said no height areas entirely through said dielectric layer to form contact windows to said substrate;

    depositing a conductive material over said dielectric layer; and

    ,planarizing said conductive layer to remove excess amounts of said conductive layer from said dielectric layer;

    wherein said second and third etching steps sequentially follow the previous etching step.

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