Plasma processing apparatus with tunable electrical characteristic

A plasma processing apparatus comprising:

• a plasma processing chamber;
• a source power (SP) coupling element configured to generate plasma in an interior of the plasma processing chamber by coupling source power to the plasma processing chamber;
• a direct current (DC) pulse generator configured to generate a DC pulse train comprising a DC pulse frequency;
• a substrate holder disposed in the interior of the plasma processing chamber;
• a DC coupling element coupled to the DC pulse generator;
• a DC current path comprising the DC coupling element, the plasma, and a reference potential node in a series configuration, the DC coupling element being configured to bias the substrate holder relative to the reference potential node using the DC pulse train;
• and
• a tuning circuit coupled between the DC coupling element and the DC pulse generator, the tuning circuit comprising a variable capacitance, the tuning circuit being configured to tune an RC time constant of the DC current path by varying the variable capacitance according to the DC pulse frequency.

A plasma processing apparatus comprising:

• a plasma processing chamber;
• a source power (SP) coupling element configured to generate plasma in an interior of the plasma processing chamber by coupling source power to the plasma processing chamber;
• a direct current (DC) pulse generator configured to generate a DC pulse train at a DC pulse frequency;
• a substrate holder disposed in the interior of the plasma processing chamber;
• a DC coupling element coupled to the DC pulse generator;
• a DC current path comprising the DC coupling element, the plasma, and a reference potential node in a series configuration, the DC coupling element being configured to bias the substrate holder relative to the reference potential node using the DC pulse train;
• and
• a capacitive pre-coat layer disposed between the DC coupling element and the plasma, the capacitive pre-coat layer increasing the RC time constant of the DC current path according to the DC pulse frequency,
• wherein the DC coupling element is disposed in or below the substrate holder, and
• wherein the reference potential node is coupled to a wall of the plasma processing chamber.