Plasma processing apparatus and method capable of performing uniform plasma treatment by control of excitation power
AssigneesAlps Electric Co., Ltd., Tadahiro Ohmi
InventorsAkira Nakano, Tadahiro Ohmi
Life of this patent
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Abstract
A plasma processing apparatus includes a chassis accommodating an impedance matching circuit. The impedance matching circuit is placed between an RF generator and a plasma excitation electrode. Magnetic probes for detecting a magnetic field generated at a slit in a sidewall of the chassis are placed axisymmetrically. The plasma processing apparatus also includes a feedback circuit for feeding back to an RF generator or a matching circuit so that a current detected by a current-detecting unit maintains a predetermined value.
Claims19
A plasma processing apparatus, comprising:
- an electrode pair of a plasma excitation electrode for forming a plasma and a susceptor electrode facing the plasma excitation electrode, a workpiece to be plasma-treated being placed therebetween;
- a plasma processing chamber accommodating the electrode pair;
- an RF generator;
- a feeding path for feeding RF power from the RF generator to the plasma excitation electrode;
- an impedance matching circuit placed in the feeding path, wherein the impedance matching circuit matches the impedance between the RF generator and the plasma processing chamber;
- a chassis accommodating the impedance matching circuit, wherein the chassis functions as part of a return path from the susceptor electrode to the RF generator;
- and
- current-detecting means for detecting an RF current which returns from the susceptor electrode to the RF generator, the current-detecting means being provided in the chassis.
A plasma processing apparatus, comprising:
- a plasma processing chamber having an electrode for exciting a plasma;
- an RF generator for supplying RF power to the electrode;
- a matching circuit for impedance matching between the plasma processing chamber and the RF generator, the matching circuit including an input terminal connected to the RF generator with an RF supplier therebetween and an output terminal connected to the electrode with an RF feeder therebetween, wherein a ground potential portion is connected between the input and output terminals;
- current-detecting means for monitoring a current flowing in the RF feeder;
- control means for controlling an output of the RF generator so that a current value detected by the current-detecting means maintains a predetermined value;
- and
- a feedback circuit for feeding back to one of the RF generator and the matching circuit a control signal from the control means to adjust the electric power applied to the electrode for exciting the plasma.
A plasma processing method using a plasma processing apparatus, comprising:
- applying electric power to an electrode for exciting a plasma to maintain a predetermined value;
- and
- monitoring by a current-detecting unit provided in the chassis the current that returns from the susceptor electrode to the RF generator;
- wherein the electric power applied to the electrode for exciting the plasma is controlled so that the current detected by the current-detecting unit maintains a predetermined value, and
- wherein the control circuit is configured to send a control signal responsive to the difference between a predetermined current value and a current detected by the current-detecting means.
A plasma processing apparatus, comprising:
- a plasma processing chamber accommodating a plasma excitation electrode and a susceptor electrode;
- an RF generator;
- a feeding path for feeding RF power from the RF generator to the plasma excitation electrode;
- an impedance matching circuit placed in the feeding path, wherein the impedance matching circuit matches the impedance between the RF generator and the plasma processing chamber;
- a chassis enclosing the impedance matching circuit, wherein the chassis functions as part of a return path from the susceptor electrode to the RF generator;
- and
- a current-detector configured to detect an RF current which returns from the susceptor electrode to the RF generator, the current-detector being provided in the chassis.
A plasma processing method in a system including an electrode pair of a plasma excitation electrode for forming a plasma and a susceptor electrode facing the plasma excitation electrode, a workpiece to be plasma-treated being placed therebetween;
- a plasma processing chamber accommodating the electrode pair;
- and an RF generator, the method comprising:
- feeding RF power from the RF generator to the plasma excitation electrode in a feeding path;
- matching the impedance between the RF generator and the plasma processing chamber in the feeding path;
- providing a return path from the susceptor electrode to the RF generator;
- and
- detecting an RF current which returns from the susceptor electrode to the RF generator in the return path.
Dependencies are inferred from the claim text.