Plasma processing apparatus
The features of the present invention are that a plasma processing apparatus includes: a process chamber in which a sample is plasma-processed; a dielectric window which airtightly seals an upper part of the process chamber; an inductive antenna which is disposed at an upper part of the dielectric window and forms an induction magnetic field; a radio frequency power source which supplies radio frequency power to the inductive antenna; and a Faraday shield to which radio frequency power is supplied from the radio frequency power source and which is disposed between the dielectric window and the inductive antenna, and the plasma processing apparatus further includes a monitoring unit which monitors a current flowing in the Faraday shield and a control unit which controls the monitored current.
1. A plasma processing apparatus comprising:
a process chamber in which a sample is plasma-processed;
a dielectric window which airtightly seals an upper part of the process chamber;
an inductive antenna which is disposed at an upper part of the dielectric window and forms an induction magnetic field;
a radio frequency power source which supplies radio frequency power to the inductive antenna;
a Faraday shield to which the radio frequency power is supplied from the radio frequency power source and which is disposed between the dielectric window and the inductive antenna;
a first variable capacitor electrically coupled at a first end to said inductive antenna and, at a second end, said first variable capacitor is also electrically coupled to (1)a first end of a second variable capacitor which is electrically coupled in series with an inductance coil to form a series resonant circuit, a second end of said inductance coil being electrically coupled to ground, and to (2) a first end of an ammeter which monitors a current flowing to the Faraday shield and which is electrically coupled at a second end with said Faraday shield; and
a control device configured to control an electrostatic capacity of the first variable capacitor such that the current monitored by said ammeter is a minimum predetermined value.
2. The plasma processing apparatus according to claim 1 , wherein the second variable capacitor controls radio frequency voltage applied to the Faraday shield and is grounded through the inductance coil.
3. The plasma processing apparatus according to claim 1 , wherein the predetermined value of said electrostatic capacity of said first variable capacitor is controlled to be 100 picofarads (pF).