Hi Bill. We have the same problem here at Uppsala University with our RIE. The problem started a few weeks ago with a flickering plasma. We could run the RIE for some minute with this flickering plasma and then is seams to change to a mode with a dark UV color. The reflected power where till zero. We change the chamber manometer and the problem disappeared for two week. Now we seem to have the same situation again. It has come to our knowledge the some one has etched silicon with diamante as a stop membrane just before the times that this problem has occurred. Maybe the carbon contaminates the chamber or the manometer. All manometers and flow meters are calibrated. The plasma seems to be little more stable if we lower the pressure. If you or anyone else comes up with idea, please let me know. ------------------------------------- Robert Lindegren, M.Sc. The Ångström Space Technology Centre