Abstract: A method and apparatus that provides in-situ monitoring of both the ion flux and the ion energy distribution of plasma processes to determine the endpoint of the etch process or the integrity and reproducibility of the deposition process where ion bombardment and energy distribution play critical roles in the process. A capacitance sensor is provided for measuring ion flux and ion distribution. At least one capacitance sensor is disposed within a plasma reactor at a first position for detecting ion flux emanating from a plasma within the plasma reactor. The capacitance sensor generates an ion flux measurement signal in response to the detection of the ion flux. Each of the at least one capacitance sensors is coupled to signal lines for routing an ion flux measurement signal outside the plasma reactor. A plurality of capacitance sensors may be formed as one of a plurality of rows of parts to be processed.