Compsite wire with noble metal cladding

Abstract

Composite wires in which a noble metal annulus is welded to an electrically-conductive, non-noble metal wire core. Methods of forming the composite wire and semiconductor packaging having at least one lead bonded to the composite wire are also disclosed.

Description

technical field [0001] The present invention relates to an electrically conductive composite noble metal wire in which a non-noble metal core is surrounded by a noble metal annular portion. Specifically, the present invention relates to a composite metal wire obtained by co-extruding a non-noble metal core material and a noble metal. The invention also relates to a method of manufacturing a composite metal wire, the core of which comprises a non-noble metal and is clad with a noble metal annular portion by co-extrusion of the non-noble metal core material and the noble metal. Background technique [0002] The development of semiconductor packaging to small pitch, long span and low packaging cost is far from meeting the needs of modern gold connecting metal wire technology. The wire elastic modulus, cost and strength require the use of a more complex wire material than the commonly used 4N gold alloy. [0003] Future connecting wires need to meet the approximately 50 micron...

AI Technical Summary

Problems solved by technology

4N gold alloys have a higher elastic modulus than pure copper, but copper-based bonding wire alloys do not meet this future demand for sufficient elastic modulus

In addition, none of these techniques can wrap the 4N gold alloy connection wire sheath on the copper wire core

[0007] US5097100 discloses that copper and gold can be drawn together, but does not give how to make micron-sized metal wires, let alone give an example of actual production

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