A method is provided for exciting at least one electrode of a capacitively coupled reactive plasma reactor containing a substrate. The electrode is excited by applying a RF voltage with a trapezoidal waveform comprising a ramp-up, a high plateau, a ramp-down and a low plateau. The plasma density can be controlled by adjusting the duration of the ramp-up, the duration of the ramp-down, the amplitude and the repetition rate of the trapezoidal waveform. The ion energy distribution function at the substrate can be controlled by adjusting the amplitude and the relative duration between the high plateau and the low plateau of the trapezoidal waveform.