US Patent 9872373 Smart multi-level RF pulsing methods

Methods of operating a plasma enhanced substrate processing system using multi-level pulsed RF power are provided herein. In some embodiments, a method of operating a plasma enhanced substrate processing system using multi-level pulsed RF power includes providing a first multi-level RF power waveform to a process chamber, the first multi-level RF power waveform having at least a first power level, a second power level, and a third power level, providing, after a first delay period, a second multi-level RF power waveform to the process chamber, the second multi-level RF power waveform having at least a first power level, a second power level, and a third power level, and processing the substrate using the first multi-level RF power waveform and the second multi-level RF power waveform to produce a features on the substrate have an aspect ratio of greater than 60:1 while maintaining an etch rate of greater than 170 nm/min.