In-depth characterization of screen-printed electrodes by laser-induced breakdown spectrometry and pattern recognition

The application of laser-induced breakdown spectrometry (LIBS) and chemometrics [namely principal component analysis (PCA) and cluster analysis ICA)I is presented for the characterization of screen-printed electrodes with in-depth resolution. An Nd:YAG laser operating at the fundamental wavelength of 1064 nm was focused on the sample and the plasma emission was collected by a fibre-optic bundle coupled to a spectrograph-charge-coupled device system. The experimental variables were optimized for a satisfactory spatial characterization. The different zones of the screen-printed electrode were studied (working electrode, reference electrode and electrical contacts) in order to identify both the composition and distribution of the layers deposited on the inert support for the construction of the electronic device. Carbon, gold, silver, platinum, palladium, titanium and aluminium were identified as major components. The use of pattern recognition techniques (PCA and CA) for the statistical treatment of the spectroscopy data obtained by LIES proved to be a powerful tool for the rapid analysis of miniaturized multilayer electronic devices. Copyright (C) 2001 John Wiley & Sons, Ltd.