Plasma processing apparatus and plasma processing method

A plasma processing apparatus comprising:

• a chamber configured to perform a plasma processing on a substrate;
• a substrate support provided inside the chamber and including an electrode, an electrostatic chuck provided on the electrode, and an edge ring disposed on the electrostatic chuck while surrounding the substrate placed on the electrostatic chuck;
• a radio-frequency power supply configured to supply radio-frequency power for generating plasma from a gas within the chamber;
• a DC power supply configured to apply a negative DC voltage to the edge ring;
• a DC power supply circuit configured to apply a DC voltage to the edge ring;
• a charge removal circuit configured to remove charges of the edge ring;
• a switch configured to switch a connection between the edge ring and the DC power supply circuit or between the edge ring and the charge removal circuit;
• and
• a controller configured to control the radio-frequency power and the DC voltage,
• wherein the controller is configured to execute a process including:
• (a) stopping the supply of the radio-frequency power, and stopping the application of the DC voltage, and then removing the charges of the edge ring,
• (b) starting the supply of the radio-frequency power, and stopping removal of the charges of the edge ring, and after a time of 0.1 μs to 1000 μs elapses since the removal of the charges of the edge ring is stopped, starting the application of the DC voltage,
• (c) performing a plasma processing on the substrate,
• (d) stopping the supply of the radio-frequency power, and stopping the application of the DC voltage, and after a time of 0.1 μs to 1000 μs elapses since the application of the DC voltage is stopped, starting the removal of the charges of the edge ring, and
• (e) repeating (a) to (d) in order.

A plasma processing method comprising:

• providing a plasma processing apparatus including:
• a chamber configured to perform a plasma processing on a substrate;
• a substrate support provided inside the chamber and including an electrode, an electrostatic chuck provided on the electrode, and an edge ring disposed on the electrostatic chuck while surrounding a substrate placed on the electrostatic chuck;
• a radio-frequency power supply configured to supply radio-frequency power for generating plasma from a gas within the chamber;
• and
• a DC power supply configured to apply a negative DC voltage to the edge ring;
• stopping application of the DC voltage while stopping supply of the radio-frequency power, and
• starting the application of the DC voltage after a predetermined delay time elapses since the supply of the radio-frequency power is started.