Plasma processing apparatus

A plasma processing apparatus, comprising:

• a vacuum processing chamber in which a sample is processed using plasma;
• a sample stage, disposed inside said vacuum processing chamber, for mounting said sample thereon;
• induction antennas disposed outside said vacuum processing chamber;
• a radio-frequency power supply for supplying a radio-frequency power to said induction antennas;
• a Faraday shield capacitively coupled with said plasma;
• a control unit;
• and
• a matching box, coupled to said radio-frequency power supply and said control unit, configured to provide a radio-frequency voltage to said Faraday shield, the matching box including:
• a series LC circuit, including a variable capacitor and an inductor, for controlling said radio-frequency voltage provided to said Faraday shield by controlling a capacitance of said variable capacitor, the series LC circuit having a resonant point with a resonant capacitance;
• a radio-frequency voltage detection unit for detecting said radio-frequency voltage provided to said Faraday shield;
• and
• a motor control circuit configured to:
• receive, from the control unit, a control signal and a preset value for the variable capacitor,
• control the capacitance of said variable capacitor based on the control signal, a prescribed radio-frequency voltage, and said detected radio-frequency voltage such that a difference between prescribed radio-frequency voltage and detected radio-frequency voltage is smaller than a predetermined value, said control signal determining whether said series LC circuit operates in a first control range of said variable capacitor, or in a second control range of said variable capacitor, the first control range having lower capacitance than the resonant capacitance of the series LC circuit, and the second control range having higher capacitance than the resonant capacitance of the series LC circuit, and
• decrease said capacitance of said variable capacitor when said control signal is set for first control range operation and said detected radio-frequency voltage is smaller than said prescribed radio-frequency voltage.

A plasma processing apparatus, comprising:

• a vacuum processing chamber in which a sample is processed using plasma;
• a sample stage, disposed inside said vacuum processing chamber, for mounting said sample thereon;
• induction antennas disposed outside said vacuum processing chamber;
• a radio-frequency power supply for supplying a radio-frequency power to said induction antennas;
• a Faraday shield capacitively coupled with said plasma;
• a control unit;
• and
• a matching box, coupled to said radio-frequency power supply and said control unit, configured to provide a radio-frequency voltage to said Faraday shield, the matching box including:
• a series LC circuit, including a variable capacitor and an inductor, for controlling said radio-frequency voltage provided to said Faraday shield by controlling a capacitance of said variable capacitor the series LC circuit having a resonant point with a resonant capacitance;
• a radio-frequency voltage detection unit for detecting said radio-frequency voltage provided to said Faraday shield;
• and
• a motor control circuit configured to:
• receive, from the control unit, a control signal and a preset value for the variable capacitor,
• control the capacitance of said variable capacitor based on the control signal, a prescribed radio-frequency voltage, and said detected radio-frequency voltage such that a difference between prescribed radio-frequency voltage and detected radio-frequency voltage is smaller than a predetermined value, said control signal determining whether said series LC circuit operates in a first control range of said variable capacitor, or in a second control range of said variable capacitor, the first control range having lower capacitance than the resonant capacitance of the series LC circuit, and the second control range having higher capacitance than the resonant capacitance of the series LC circuit, and
• decrease said capacitance of said variable capacitor when said control signal is set for second control range operation and said detected radio-frequency voltage is larger than said prescribed radio-frequency voltage.

A plasma processing apparatus, comprising:

• a vacuum processing chamber in which a sample is processed using plasma;
• a sample stage, disposed inside said vacuum processing chamber, for mounting said sample thereon;
• induction antennas disposed outside said vacuum processing chamber;
• a radio-frequency power supply for supplying a radio-frequency power to said induction antennas;
• a Faraday shield capacitively coupled with said plasma;
• a control unit;
• and
• a matching box, coupled to said radio-frequency power supply and said control unit, configured to provide a radio-frequency voltage to said Faraday shield, the matching box including:
• a series LC circuit, including a variable capacitor and an inductor, for controlling said radio-frequency voltage provided to said Faraday shield by controlling a capacitance of said variable capacitor, the series LC circuit having a resonant point with a resonant capacitance;
• a radio-frequency voltage detection unit for detecting said radio-frequency voltage provided to said Faraday shield;
• and
• a motor control circuit configured to:
• receive, from the control unit, a control signal and a preset value for the variable capacitor,
• control the capacitance of said variable capacitor based on the control signal, a prescribed radio-frequency voltage, and said detected radio-frequency voltage such that a difference between prescribed radio-frequency voltage and detected radio-frequency voltage is smaller than a predetermined value, said control signal determining whether said series LC circuit operates in a first control range of said variable capacitor, or in a second control range of said variable capacitor, the first control range having lower capacitance than the resonant capacitance of the series LC circuit, and the second control range having higher capacitance than the resonant capacitance of the series LC circuit, and
• increase said capacitance of said variable capacitor when said control signal is set for second control range operation and said detected radio-frequency voltage is smaller than said prescribed radio-frequency voltage.