Abstract: A method of processing a substrate that includes: exposing the substrate in a plasma processing chamber to a plasma powered by applying a first power to a first electrode of a plasma processing chamber; turning OFF the first power to the first electrode after the first time duration; while the first power is OFF, applying a second power to a second electrode of the plasma processing chamber for a second time duration, the second time duration being shorter than the first time duration, an energy of the second power over the second time duration is less than an energy of the first power over the first time duration by a factor of at least 2; and detecting an optical emission spectrum (OES) from species in the plasma processing chamber.

Abstract: A method of processing a substrate that includes: exposing the substrate in a plasma processing chamber to a plasma powered by applying a first power to a first electrode of the plasma processing chamber for a first time duration; and after the first time duration, determining a process endpoint by: while exposing the substrate to the plasma by applying the first power to the first electrode, applying a second power to a second electrode of the plasma processing chamber for a second time duration that is shorter than the first time duration; and obtaining an optical emission spectrum (OES) from the plasma while applying the second power to the second electrode, where an energy of the second power over the second time duration is less than an energy of the first power over a sum of the first and the second time durations by a factor of at least 2.

Abstract: A method of characterizing a plasma in a plasma processing system that includes: generating a pulsed plasma in a plasma processing chamber of the plasma processing system, the pulsed plasma being powered with a pulsed power signal, each pulse of the pulsed plasma including three periods: a overshoot period, a stable-ON period, and a decay period; performing cyclic optical emission spectroscopy (OES) measurements for the pulsed plasma, the cyclic OES measurements including: obtaining first OES data during one of the three periods from more than one pulses of the pulsed plasma; and obtaining a characteristic of the pulsed plasma for the one of the three periods based only on the first OES data.