Electrodeposition of Ni-Fe micro-pillars using laser drilled templates

Abstract

Extremely magnetically soft materials are essential for the sensing elements of very high sensitivity bio-magnetic field sensors. It was recently reported that the sensitivity of a multi-core orthogonal fluxgate sensor increases exponentially with the number of the ferromagnetic cores in the sensing element. Thus in order to maximize the number of sensing element within a miniaturized sensor, an array of micro-wires on copper substrates (for electrical connectivity) needs to be developed. In this study, arrays of Ni80Fe20 micro-wires on copper substrates are developed using template-assisted electrodeposition. A layer of paint was applied on a polished copper substrate and arrays of micro-holes on the paint layer are drilled by laser machining. Using laser fabrication technique, flat and concave surfaces were also created on the copper substrate and the effect of such surfaces on the permalloy growth structures was investigated. The results showed that when the substrate surfaces were flat, solid pillars were grown while hollow pillars were grown when the substrate surfaces were concaved. © 2007 Elsevier B.V. All rights reserved.