摘要 |
A method for forming a variable thickness Cu seed layer on a substrate for a subsequent Cu electrochemical plating process, where the Cu seed layer thickness profile improves uniformity of the electroplated Cu layer compared to when using a constant thickness Cu seed layer. The method includes depositing a Ru metal layer on the substrate, depositing a variable thickness Cu seed layer on the Ru metal layer by a physical vapor deposition process, whereby the variable thickness Cu seed layer is deposited with a Cu thickness at the edge of the substrate that is less than a Cu thickness at the center of the substrate, and plating bulk Cu onto the variable thickness Cu seed layer. The Ru metal layer may be a variable thickness Ru metal layer, or alternately, the Ru metal layer may have a substantially uniform Ru metal thickness across the substrate.
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