Plasma processing method and plasma processing apparatus

The A plasma processing method performed in a plasma processing apparatus,

• wherein the plasma processing apparatus comprises:
• a chamber main body in which a chamber is provided;
• a stage, including a lower electrode, provided within the chamber main body and configured to support a substrate placed thereon;
• a radio frequency power supply configured to supply a radio frequency power for exciting a gas supplied into the chamber;
• and
• one or more DC power supplies configured to generate a negative DC voltage to be applied to the lower electrode,
• wherein the plasma processing method comprises:
• supplying the radio frequency power from the radio frequency power supply to generate plasma of the gas supplied into the chamber;
• and
• applying the negative DC voltage to the lower electrode from the one or more DC power supplies to attract ions in the plasma onto the substrate,
• wherein, in the applying of the negative DC voltage, the negative DC voltage is applied to the lower electrode periodically, and a duty ratio is set to be equal to or less than 40%, wherein the duty ratio is a percentage occupied within a single cycle by a period during which the negative DC voltage is applied to the lower electrode, and
• wherein the supplying of the radio frequency power is stopped in the period during which the negative DC voltage is applied, and the radio frequency power is supplied in a period during which the applying of the negative DC voltage is stopped.

A plasma etching apparatus, comprising:

• a chamber main body in which a chamber is provided;
• a stage, including a lower electrode, provided within the chamber main body and configured to support a substrate placed thereon;
• a radio frequency power supply configured to supply a radio frequency power for exciting a gas supplied into the chamber;
• one or more DC power supplies configured to generate a negative DC voltage to be applied to the lower electrode;
• a switching unit configured to allow the application of the negative DC voltage to the lower electrode to be stopped;
• and
• a controller configured to control the switching unit,
• wherein the controller controls the switching unit such that the negative DC voltage from the one or more DC power supplies is applied to the lower electrode periodically to attract ions in plasma of a gas generated within the chamber onto the substrate and a plasma etching process is performed on the substrate, and such that a duty ratio is set to be equal to or less than 40%, wherein the duty ratio is a percentage occupied within a single cycle by a period during which the negative DC voltage is applied to the lower electrode.