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Catalytic Electrode

IP.com Disclosure Number: IPCOM000093903D
Original Publication Date: 1966-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Miller, LF: AUTHOR

Abstract

This electrode paste, upon firing, is readily plated to provide a strong electrode having increased conductance, solderability and stability. The ease in plating is imparted by the presence of a catalyst in the paste.

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Catalytic Electrode

This electrode paste, upon firing, is readily plated to provide a strong electrode having increased conductance, solderability and stability. The ease in plating is imparted by the presence of a catalyst in the paste.

An electrode is formed by applying to and then firing on an alumina ceramic substrate a conductive metallizing paste. The electrode is formed into a desired circuit pattern. The latter provides a conductive link between clips, leads or pins attached to or embedded in the substrate and planar semiconductor or chip devices bonded to the electrode after pre-tinning the pattern with solder.

Frequently such electrodes are plated to increase their strength and solderability. However, in electroless nickel plating, the electrode does not readily accept the plating substance without some form of external catalysis. The inclusion of a binary internal catalyst, such as a combination of approximately equal quantities of colloidal silica and palladium powder in the electrode paste, permits the fired electrode to be readily plated without external catalysis.

A typical formulation for the electrode paste, which is normally applied by silk screening and fired at 800-900 degrees C, is, by weight, 67% solids (92% gold powder, 5% palladium black and 3% colloidal silica), 3% lead borosilicate glass, and 30% of an inert liquid vehicle which can contain gold resinate. Metal powders other than gold can be used such as the members of the platinum serie...