Manufacture of fine-grained electroplating anodes
AssigneeBrush Wellman Inc.
InventorsWilliam J. Bishop, David Krus, Jr.
Life of this patent
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Abstract
A continuously cast copper ingot is made by a procedure in which turbulence is imparted to the metal/solid interface during the casting operation. The ingot is then hot worked to form a billet having a smaller average grain size and a larger diameter than possible in the past. The billet is especially useful for making electroplating anodes used in the damascene process for making copper interconnects in silicon wafers.
Claims26
A process for producing a billet useful for making an electroplating anode comprising
- forming a copper or copper alloy ingot by turbocasting, and
- hot working the ingot so formed to form the billet.
A copper or copper alloy billet useful for making an electroplating anode, the billet having a diameter of at least about 200 mm and an average grain size of about 175 μm or less.
An anode for mounting in an electrodeposition system for carrying out the damascene process comprising a shaped article formed from copper or a copper alloy, the shaped article being 2 to 6 inches thick and defining a major face having a minimum transverse dimension of about 200 mm, the major face being machined flat for receiving a semiconductor wafer, the shaped article defining an opposite face opposite the major face for mounting the anode in the electrodeposition system, the copper or copper alloy forming the anode having an average grain size of about 175 μm or less.
A process for producing a billet useful for making an electroplating anode, the billet having a diameter of at least about 200 mm and an average grain size of about 175 μm or less, the process comprising
- forming a copper or copper alloy ingot by turbocasting, and
- hot working the ingot so fanned by at least 3 to 1 but no more than about 6 to 2 in terms of area reduction to thereby form the billet without cold working.
A process comprising hot working a copper or copper alloy ingot formed by turbocasting to form a billet having a diameter of at least about 200 mm and an average grain size of about 175 μm or less.
Dependencies are inferred from the claim text.