Lucent Technologies Inc.

Alan Blair

Joseph Anthony Abys

Chonglun Fan

Chen Xu

Edward J Kudrak

Michael L Ammerman

Jimmy Chun Wah Kwok

In accordance with the invention, the quality of hard gold is determined by Raman vibrational spectroscopy. A sample of the hard gold is provided, a monochromatic light beam is directed onto the sample, and the frequency and intensity of the light scattered by the sample is analyzed for the vibrational frequencies of polymer molecules. Scattering frequencies offset from the initial beam frequency by about 2132 cm and about 2182 cm , for example, are indicative of high quality nickel-hardened gold.

Method of determining the quality of hard gold

In accordance with the invention, a packaged electronic device comprises at least one electronic device and leads sealed within a protective package. The leads comprise a conductive metal substrate having a composite metal finish with a total thickness of 1000 &angst; or less. The finish comprises, in succession from the substrate, 25-750 &angst; of palladium alloy and 5-250 &angst; of wirebondable and solderable material. The substrate is advantageously nickel-plated copper alloy or Fe&mdash;Ni alloy. The content of palladium in the palladium alloy coating can range from 10-95 weight percent. This finish meets requirements of wirebonding and solderability at a thickness surprisingly lower than previously used packaging finishes.

Ultra-thin composite surface finish for electronic packaging

A surface finish which provides improved wirebonding performance for integrated circuit packages is disclosed. The surface finish which is formed on a substrate includes a palladium layer and one or more material layers. The one or more material layers are interposed between the substrate and the palladium layer. The palladium layer has a hardness that is less than about 500 (KHN.sub.50) while at least one material layer has a hardness that is less than about 250 (KHN.sub.50).

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Murray Hill, NJ, United States of America

Alan Blair