Browse Prior Art Database

Indium Oxide as a Solderability Inhibiting Agent

IP.com Disclosure Number: IPCOM000094981D
Original Publication Date: 1965-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

De Paolo, GJ: AUTHOR

Abstract

Indium oxide can be added in small quantities to normally lead-tin solderable conductive electrodes to completely prevent solderability.

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Indium Oxide as a Solderability Inhibiting Agent

Indium oxide can be added in small quantities to normally lead-tin solderable conductive electrodes to completely prevent solderability.

One to four per cent by weight of indium oxide powder having a surface area of about 60m/2//gm, an average particle size of about 0.02 microns and an oil absorption of about 27 lbs. oil/100 lbs. is added to each of the finely divided conductive powder compositions in the following table.

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The conductive powder and indium oxide powder in each example are each initially mixed with an organic vehicle in proportion of 77 parts by weight powder to 23 parts by weight vehicle. The resulting paste mixtures are each screened onto different alumina substrate, fired at 750 deg. C. for 30 minutes and cooled to room temperature. Each resulting conductor is dipped into a 90 lead-10 tin liquid solder bath. No significant solder adheres to any of the conductors as indicated in the table. The presence of the indium oxide in the conductors of examples 1 and 4 additionally prevents dissolving of the conductors in the solder. Without the indium oxide, gold conductors are substantially dissolved in the solder bath.

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