Plasma processing apparatus

A plasma processing apparatus comprising:

• a plasma processing chamber;
• a substrate support disposed in the plasma processing chamber and including a lower electrode;
• an upper electrode disposed above the substrate support;
• an RF signal generator coupled to the lower electrode and configured to generate an RF signal, the RF signal having a first power level during a first state in a repetition period, a second power level less than the first power level during a second state in the repetition period, and the second power level during a third state in the repetition period;
• a first DC signal generator coupled to the lower electrode and configured to generate a first DC signal, the first DC signal having a first voltage level during the first state, a sequence of voltage pulses having a second voltage level during the second state, and the first voltage level during the third state, an absolute value of the first voltage level being less than an absolute value of the second voltage level;
• and
• a second DC signal generator coupled to the upper electrode and configured to generate a second DC signal, the second DC signal having a third voltage level during the first state, and a fourth voltage level during the second state, an absolute value of the third voltage level being greater than an absolute value of the fourth voltage level.