Plasma processing method and plasma processing apparatus

A plasma processing apparatus comprising:

• a chamber;
• a substrate support that includes a base and is configured to support a substrate in the chamber;
• a radio frequency power source configured to supply radio frequency power to generate plasma from gas in the chamber;
• a bias power source configured to apply a negative direct-current voltage to the substrate support, and
• a controller configured to control the radio frequency power source and the bias power source,
• wherein the controller is configured to perform first control in a first period, the first control including controlling the radio frequency power source to supply the radio frequency power to generate plasma in the chamber in a state where the negative direct-current voltage from the bias power source is not applied to the substrate support,
• the controller is configured to perform second control in a second period following the first period, the second control including controlling the radio frequency power source to stop supply of the radio frequency power, in a state where the negative direct-current voltage from the bias power source is not applied to the substrate support, and
• the controller is configured to perform third control in a third period following the second period, the third control including controlling the bias power source to apply the negative direct-current voltage to the substrate support in a state where the radio frequency power from the radio frequency power source is not supplied, the negative direct-current voltage being set to generate ions in the chamber by secondary electrons that are emitted by causing ions in the chamber to collide with the substrate on the substrate support.