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Electroformed conductor patterns in electronics manufacturing

Teija Laine-Ma (Tampere University of Technology, Pori, Finland)
Pekka Ruuskanen (Tampere University of Technology, Pori, Finland)
Satu Pasanen (VTT Technical Research Centre of Finland, Tampere, Finalnd)
Mikko Karttunen (VTT Technical Research Centre of Finland, Tampere, Finalnd)

Circuit World

ISSN: 0305-6120

Article publication date: 28 October 2014

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Abstract

Purpose

The aim of this study was to test and survey a circuitry transfer technique where conductor patterns are electroformed on carrier substrates and thereafter the electroformed patterns are transferred from carrier substrates to their final devices.

Design/methodology/approach

An electrically conductive pattern is built up by an electrodepositing metal or metal alloy on a carrier substrate, called a mandrel, using a resist image to define the outlines of the pattern. Thereafter, the electroformed structures are bonded on plastic substrates, for instance, by hot pressing or by embedding into a resin. In our experiments, the imaging of stainless steel carriers was done by the photolithographic process and the electroformed copper patterns were transferred by hot pressing onto thermoplastic substrates.

Findings

The literature review revealed that the transfer of electroformed conductor patterns to plastic parts is not a very commonly used technology, although it could provide possibilities for even quite specific structures in electronics manufacturing at an affordable price. Our tests indicated that the acidic peroxide-sulfuric pre-treatment of electroformed copper patterns before hot press bonding clearly improved the adhesion of copper on both acrylonitrile butadiene styrene and polyphenylene oxide substrates and that a steel template around the substrate during hot pressing process can restrict dimensional changes in thermoplastic substrates significantly.

Originality/value

This paper contains a survey and preliminary testing of the electroformed circuitry transfer technique. The analysis of the test boards focused on the adhesion between copper strips and thermoplastic substrates and on the factors affecting adhesion. Finally, the paper introduces the advantages and drawbacks of the technique.

Keywords

Acknowledgements

The study was conducted as a part of the “Eco-circuit boards” project, which is funded by TEKES – the Finnish Funding Agency for Technology and Innovation, the Federation of Finnish Technology Industries and Finnish industrial companies.

Citation

Laine-Ma, T., Ruuskanen, P., Pasanen, S. and Karttunen, M. (2014), "Electroformed conductor patterns in electronics manufacturing", Circuit World, Vol. 40 No. 4, pp. 150-159. https://doi.org/10.1108/CW-06-2014-0022

Publisher

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Emerald Group Publishing Limited

Copyright © 2014, Emerald Group Publishing Limited