Electrical Contact Resistance in Thin (<= 0.5 mu m) Gold Plated Contacts: Effect of Gold Plating Thickness

Misra, Prashant and Nagaraju, J (2010) Electrical Contact Resistance in Thin (<= 0.5 mu m) Gold Plated Contacts: Effect of Gold Plating Thickness. In: IEEE Transactions on Components and Packaging Technologies, 33 (4). pp. 830-835.

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Abstract

This paper describes the electrical contact resistance (ECR) measurements made on thin gold plated (gold plating of <= 0.5 mu m with a Ni underlayer of similar to 2 mu m) oxygen free high conductivity (OFHC) Cu contacts in vacuum environment. ECR in gold plated OFHC Cu contacts is found to be slightly higher than that in bare OFHC Cu contacts. Even though gold is a softer material than copper, the relatively high ECR values observed in gold plated contacts are mainly due to the higher hardness and electrical resistivity of the underlying Ni layer. It is well known that ECR is directly related to plating factor, which increases with increasing coating thickness when the electrical resistivity of coating material is more than that of substrate. Surprisingly, in the present case it is found that the ECR decreases with increasing gold layer thickness on OFHC Cu substrate (gold has higher electrical resistivity than OFHC Cu). It is analytically demonstrated from the topography and microhardness measurements results that this peculiar behavior is associated with thin gold platings, where the changes in surface roughness and microhardness with increasing layer thickness overshadow the effect of plating factor on ECR.

Item Type:	Journal Article
Publication:	IEEE Transactions on Components and Packaging Technologies
Publisher:	IEEE
Additional Information:	Copyright 2010 IEEE. Personal use of this material is permitted.However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords:	Electrical contact resistance;oxygen free high conductivity (OFHC) Cu;plating factor;thin gold plating.
Department/Centre:	Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics Division of Physical & Mathematical Sciences > Physics
Date Deposited:	18 Feb 2011 07:26
Last Modified:	18 Feb 2011 07:26
URI:	http://eprints.iisc.ac.in/id/eprint/35551

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