Conference Program - LOPE-C 2011

SCIENTIFIC CONF. | THURSDAY-JUNE 30, 2011
Track 4
Inorganic Materials (11:30 am - 01:20 pm) | LOCATION HARMONIE D / LEVEL C2
12:20 pm Effect of nanoparticle distribution and ink composition on the electrical resistivity of laser annealed inkjet printed silver interconnects in a real-time experiment
Dr Alessandro Chiolerio,
Politecnico di Torino, Italy
We report a study on the effects induced by nanoparticle (NP) diametre distribution and solvent
choice on the electrical resistivity of silver lines realized by means of inkjet printing on a flexible
kapton substrate. In a previous work a laser annealing process to promote sinterization was
exploited to reach the best results in terms of conductivity and was compared to a more traditional
hotplate annealing [1]. The Ag ink we used is basically an aqueous colloidal dispersion of silver
nanoparticles (NP) [2]; a specific synthesis procedure allowed us to control the diametre
distribution. Metal NP are dispersed in a mixed solvent of propylene/ethylene glycol, water and
ethanol; the solid loading of the ink is 21-24 wt %. The ink-jet printed silver lines were realized
using a piezoelectric Jetlab® 4 printer from MicroFab Technologies Inc. A thermal treatment was
performed in order to promote NP coalescence, allowing complete solvent removal and electrical
percolation. Both the classical hotplate and a Diode Pumped Solid State (DPSS) laser beam within a
specific range of power / speed conditions were experimented, using a specific test fixture allowing
the acquisition of real-time resistance profiles during either the laser annealing or the hot-plate one.
The laser used to anneal the sample was a DPPS laser system made by Microla Optoelectronics
(MLQ-20 series). This DPSS laser system has an end-pump configuration and an output wavelength
of 1064 nm linearly polarized with a maximum power density of 1300 W/cm2 in continuous wave
mode. The effects of geometry, NP distribution and solvent were clarified.
[1] A. Chiolerio, G. Maccioni, P. Martino, M. Cotto, P. Pandolfi, P. Rivolo, S. Ferrero and L.
Scaltrito, Microelectron. Eng. (2011), in press, doi: 10.1016/j.mee.2010.12.099;
[2] P. Martino, M. Cotto, P. Rivolo and A. Chiolerio, Italian Patent TO2010A000571.
page 88