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Enhanced Dry Solder Wetting using Au/PtCoating Layer

IP.com Disclosure Number: IPCOM000040916D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Chang, CA: AUTHOR [+2]

Abstract

A thin film platinum layer can be incorporated between an anti- oxidant layer and a conducting layer in a solder profile to achieve excellent dry solder wetting.

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Enhanced Dry Solder Wetting using Au/PtCoating Layer

A thin film platinum layer can be incorporated between an anti- oxidant layer and a conducting layer in a solder profile to achieve excellent dry solder wetting.

In dry solder wetting, a coating metal is used to protect the conducting layer underneath the coating metal from reacting with air. For example, in dry soldering with copper as the conducting layer, a gold/copper interface is used wherein the gold layer is intended to prevent outdiffusion and subsequent oxidation of the copper. However, these coating metals and gold, in particular have been found to be less than acceptable as an oxidation and diffusion barrier. Many metals are known to outdiffuse through the overcoating layer to the surface and become oxidized, therefore preventing subsequent wetting and joining by solder.

Such problems can be solved by incorporating a thin film platinum layer between the anti-oxidant and conducting layer to achieve excellent dry solder wetting. For example, a Au/Pt/Cu interface can be formed wherein there is only interdiffusion between copper and platinum and there is no outdiffusion of copper to the gold surface. The Au/Pt/Cu layers can be deposited by a variety of any well known deposition techniques wherein the thickness of the layers are equal and between 1000-2000Ao each.

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