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Browse Prior Art Database

Surface Improvements of Copper Spheres

IP.com Disclosure Number: IPCOM000096330D
Original Publication Date: 1963-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bolda, FJ: AUTHOR [+3]

Abstract

Miniature electronic devices utilize copper spheres as electrical terminals. In this application, nearly perfect sphericity and high electrical conductivity are required in the copper sphere. To provide spheres which satisfy these conditions, it is necessary that the sphere surface have a high degree of smoothness and be free of defects.

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Surface Improvements of Copper Spheres

Miniature electronic devices utilize copper spheres as electrical terminals. In this application, nearly perfect sphericity and high electrical conductivity are required in the copper sphere. To provide spheres which satisfy these conditions, it is necessary that the sphere surface have a high degree of smoothness and be free of defects.

This is accomplished by treating copper spheres, produced in one of several known procedures, in a reducing atmosphere at high temperature. The spheres are placed on a flat, grooved, or recessed non-wetting substrate such as alumina. The substrate is positioned in a container which is lined with copper. The spheres are then exposed to reducing atmosphere such as hydrogen or forming gas and heated to a temperature slightly below the melting point of copper. This is for a sufficient period of time to remove any surface defects. Following this the spheres are quenched in a nitrogen atmosphere.

With this procedure, copper spheres having the desired surface characteristics are produced.

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