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Cobalt first layer advanced metallization for interconnects

  • US 9,852,990 B1
  • Filed: 08/17/2016
  • Issued: 12/26/2017
  • Est. Priority Date: 08/17/2016
  • Status: Active Grant
First Claim
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1. A method for fabricating an advanced metal conductor structure comprising:

  • providing a pattern in a dielectric layer, wherein the pattern includes a set of features in the dielectric for a set of metal conductor structures;

    creating an adhesion promoting layer disposed over the patterned dielectric;

    depositing a ruthenium metal layer disposed over the adhesion promoting layer;

    using a physical vapor deposition process to deposit a cobalt layer disposed over the ruthenium layer;

    performing a thermal anneal which reflows the cobalt layer to fill a first portion of the set of features leaving a second, remaining portion of the set of features unfilled, wherein the reflowed cobalt layer has a u-shaped cross-section having a thicker bottom layer than side layers; and

    depositing a second metal layer to fill the second, remaining portion of the set of features, wherein the second metal is a metal other than cobalt;

    wherein a thickness of the reflowed cobalt layer from the ruthenium layer to a bottom of the second metal layer and a thickness of the second metal layer after planarization are substantially equal.

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