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Fabrication of Circuits on Flexible Substrates Using Conductive SU-8 for Sensing Applications

Authors :
Carlos D. Gerardo
Robert Rohling
Edmond Cretu
Source :
Sensors (Basel, Switzerland), Sensors; Volume 17; Issue 6; Pages: 1420
Publication Year :
2017

Abstract

This article describes a new low-cost rapid microfabrication technology for high-density interconnects and passive devices on flexible substrates for sensing applications. Silver nanoparticles with an average size of 80 nm were used to create a conductive SU-8 mixture with a concentration of wt 25%. The patterned structures after hard baking have a sheet resistance of 11.17 Ω /□. This conductive SU-8 was used to pattern planar inductors, capacitors and interconnection lines on flexible Kapton film. The conductive SU-8 structures were used as a seed layer for a subsequent electroplating process to increase the conductivity of the devices. Examples of inductors, resistor-capacitor (RC) and inductor-capacitor (LC) circuits, interconnection lines and a near-field communication (NFC) antenna are presented as a demonstration. As an example of high-resolution miniaturization, we fabricated microinductors having line widths of 5 μ m. Mechanical bending tests were successful down to a 5 mm radius. To the best of the authors’ knowledge, this is the first report of conductive SU-8 used to fabricate such planar devices and the first on flexible substrates. This is a proof of concept that this fabrication approach can be used as an alternative for microfabrication of planar passive devices on flexible substrates.

Details

ISSN :
14248220
Volume :
17
Issue :
6
Database :
OpenAIRE
Journal :
Sensors (Basel, Switzerland)
Accession number :
edsair.doi.dedup.....e9e42dc8d33f518bb10d7869590c87e3