Abstract: A plasma processing system and method for operating a windowless optical diagnostic system in conjunction with a plasma processing system. The plasma processing system comprises a windowless optical diagnostic system that is constructed and arranged to detect a plasma process condition. The method includes providing a first pressure within a chamber of the plasma processing system and providing a second pressure within a windowless optical diagnostic chamber in which the windowless optical diagnostic system is positioned. The method further includes controlling the second pressure within the windowless optical diagnostic chamber relative to the first pressure within the chamber and optically detecting a plasma process condition.

Abstract: An apparatus and method for monitoring a plasma etch process are disclosed which will provide for in-situ measurement of plasma wafer-charge damage with both temporal and spatial resolution. A removable test structure comprising a test wafer that may take the form of a silicon substrate with one or more test devices is provided with backside contacts. Test devices such as capacitors, MOS transistors, etc., which may be provided with antennas, are provided on the top surface of the wafer which can be electrically contacted on the backside of the substrate. The apparatus also includes a wafer chuck provided with contacts which electrically engage the back-side contacts on the substrate and communicating with the outside of the plasma chamber so that the electrical signals generated in the test devices may be measured in real-time while the plasma process is being performed on the substrate.