Conference Program - LOPE-C 2011

SCIENTIFIC CONF. | THURSDAY-JUNE 30, 2011
Track 4
Novel Inks and Processes (04:30 pm - 06:00 pm) | LOCATION HARMONIE D / LEVEL C2
05:40 pm Electrical sintering of printed metal structures for mechanical sensors
Mr Christian Werner,
Fraunhofer IFAM, Germany
Today, physico-mechanical sensors like strain gauges, thermo-elements or resistance thermosensors are often discrete devices that have to be mounted onto the surface
of the part (SMD). With the evolving possibilities of printed electronics it is desired not only to print conductive patterns but additionally sensors or sensor arrays. Maskless
printing techniques, like Ink Jet and Aerosol Jet®, are able to print microstructured metal patterns from nanoparticulate inks on virtually any substrate. The thermal
treatment of the printed structure is often done by furnace, with temperatures usually above 150 °C. Furnace sintering results not only in a high thermal load of the whole
part or substrate, but also limits the general substrate selection. Another issue for sintering printed structures is the differing of electrical resistivities due to variations in
process reliability of maskless printing processes for specific printed patterns, like strain gauges.
The electrical sintering process is an unconventional, but promising candidate for sintering printed metal patterns to a specific target resistivity, as well as reducing the
thermal load on the substrate. This work is focusing on the characterization of electrically sintered printed metal structures in comparison to the thermal processing of these
structures by furnace. For this purpose, commercially available conductive inks, like gold or silver as well as resistive inks under development, like copper-nickel, are
printed by Ink Jet or Aerosol Jet® on various substrates.
With electrical sintering, it was possible to achieve highly conductive metal structures within some seconds of treatment. Besides electrical characterization, scanning
electron microscopy with focused ion beam is used to analyze surface morphologies and cross-sectional areas of the different metals after electric and conventional
sintering. Further on, dynamic testing of printed strain gauges is performed to give information about the mechanical load capacity.
06:00 pm SESSION END
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