US Patent 9544987 Frequency tuning for pulsed radio frequency plasma processing

This disclosure describes systems, methods, and apparatus for pulsed RF power delivery to a plasma load for plasma processing of a substrate. In order to maximize power delivery, a calibration phase using a dummy substrate or no substrate in the chamber, is used to ascertain a preferred fixed initial RF frequency for each pulse. This fixed initial RF frequency is then used at the start of each pulse during a processing phase, where a real substrate is used and processed in the chamber.