MICROBEAM RBS ON FLAT-PANEL DISPLAYS

We have demonstrated the utility of microbeam-Rutherford BackScatterin g (mu-RBS) in spatially resolved studies of operational plasma effects on the interior surfaces of plasma flat panel displays manufactured b y Photonics Imaging. The experiments were performed at the Sandia Nucl ear microprobe using a 2.8 MeV He beam with an average beam spot size of less than 8 mu m. The interior surface of the top panes of the flat panels is composed of approximately 800 nm of MgO on top of a 2000 nm thick PbO layer. mu-RBS of sample panels operated under varying condi tions measured changes in the surface MgO film thickness due to plasma erosion and redeposition as accurately as +/-1.5 nm. The high accurac y in the MgO thickness measurement was achieved by inferring the MgO t hickness from the shift of the Pb front edge in the RBS spectrum. An e stimate for the thickness accuracy as a function of the acquired stati stics is presented. The surface of the flat panels' bottom panes is al so comprised of MgO on top of PbO. However, troughs similar to 100 mu m wide by 10 mu m deep were partially filled with phosphor and cover t he entire width of the surface. This leaves only 100 mu m long section s of MgO within the trough exposed. Using mu-RBS, we were able to anal yze the surface composition of these regions. (C) 1997 Elsevier Scienc e B.V.