Laserinduzierte Plasmaspektroskopie zur Online-Prozesskontrolle

6th Euro-Mediterranean Symposium on Laser-Induced
Breakdown Spectroscopy (EMSLIBS 2011),
11-15 September 2011, Çeşme/Izmir, Turkey

In this field of activity we are investigating micro-structuring of thin indium tin oxide (ITO) layers under process control with a semi-quantitative LIBS analysis. ITO (In2O3)x:(SnO2)1-x film is an optically transparent conducting material widely used for various industrial products, such as novel organic solar cells and liquid crystal displays (LCD). The fast LIBS technique can be well used for both micro-structuring and simultaneously analyzing the elemental composition of coatings and substrates. Therefore, LIBS may help to control micro-structuring of ITO layers in real-time. The data acquisition and analysis are possible instantly and results are available within milliseconds. Using a fast grating Echelle array spectrometer in a standard experimental LIBS setup we spectroscopically study the ablation process by irradiating different quantities of short laser pulses focused on the ITO film of a conventional ITO coated plate. A characteristic isolated spectral emission line of indium can be easily observed decreasing at 451.13 nm during the ablation process. Since the ITO coated plate is made of glass the typical sodium doublet around 589 nm is strongly increasing. In an industrial micro-structuring process this indicates that laser ablation must be stopped to prevent from further damages of the substrate. Images of the ablation were made with a scanning electron microscope (SEM). The elemental composition of the ITO layer could be confirmed by energy dispersive X-ray (EDX) spectroscopy.