The use of RF monitoring systems for plasma enhanced chemical vapor deposition (PECVD) tools in an advanced microelectronics production environment is discussed. Data obtained from the measurement of RF current and voltage at the input to the process chamber provides valuable process information that is unavailable from data recorded using traditional process control techniques, such as RF forward and reflected power. RF current and voltage data is presented for silicon oxide and nitride films deposited in commercial PECVD reactors. The application of this data to improvement of the periodic chamber cleaning process with the goal of reducing gas emissions and chamber contamination will be shown. In - film wafer contamination measurements showed an improvement of 10 X in number of particles when the improved clean was implemented. RF measurements have also been used to improve the effectiveness of post - clean chamber seasoning, by giving an indication of the completion of the seasoning. Inadequate seasoning will result in increased variability of film thickness and stress. Changes in RF current and voltage during the deposition process give an indication of this increase in variability. Finally, the application of RF measurements to reactor matching will be discussed; RF signal strength of different reactors running the same process can be compared in order to understand and control performance differences between the reactors.