Plasma processing apparatus and plasma processing method

Abstract

The invention provides a plasma processing apparatus and a plasma processing method capable of controlling the voltage of the processing substrate with high accuracy, thereby enabling a highly accurate plasma processing. According to the invention, a voltage Vw of the processing substrate is measured using a processing substrate with a voltage probe prepared in advance, and based on a bias voltage Vesc applied to an electrostatic chuck mechanism 200 and a bias current Iesc flowing through the electrostatic chuck mechanism 200, a capacity component Cesc which is an impedance representing the electric property of the electrostatic chuck mechanism 200 is computed numerically. Then, based on a predetermined expression, the voltage Vw of the processing substrate 102 is estimated using the bias voltage Vesc of the processing substrate 102 to be measured, the bias current Iesc flowing through the electrostatic chuck mechanism 200 and the capacity component Cesc which is the impedance acquired in advance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing one embodiment of the plasma processing apparatus to which the present invention is applied;

FIG. 2 is an explanatory view showing the peripheral structure of the substrate electrode according to the present invention;

FIGS. 3A and 3B are views showing the measured values of voltages and currents of portions of the substrate electrode, and estimated values of the processing substrate voltage according to the present invention; and

FIG. 4 is a view showing the equivalent circuit model of the peripheral area of the substrate electrode according to the present invention.

Claims

1. A plasma processing apparatus for subjecting a processing substrate to plasma processing, the apparatus comprising: a processing chamber for storing the processing substrate;a substrate electrode having an electrostatic chuck mechanism for attracting and supporting the processing substrate electrostatically;a plasma generating means for supplying plasma to the processing substrate;a bias voltage applying means for applying bias voltage to the processing substrate placed on the substrate electrode; andan impedance value storage means for storing an impedance value of the electrostatic chuck mechanism, the impedance value acquired by measuring a voltage of a processing substrate for measurement placed on the substrate electrode, and using a capacity component of the electrostatic chuck mechanism, the bias voltage applied to the electrostatic chuck mechanism and a bias current flowing through the electrostatic chuck mechanism;wherein the voltage of the processing substrate to be subjected to plasma processing is estimated using the bias voltage value and the bias current value applied to the processing substrate actually subjected to plasma processing, and using the acquired impedance value of the electrostatic chuck mechanism.

2. The plasma processing apparatus according to claim 1, wherein a power supply output of the bias voltage applying means is controlled through use of an estimated potential of the processing substrate.

3. The plasma processing apparatus according to claim 1, wherein the impedance value storage means takes in and stores the bias voltage and the bias current applied to the electrostatic chuck mechanism, and further stores the impedance value representing the electric property of the electrostatic chuck mechanism;the means for estimating the voltage value of the processing substrate estimates the voltage value of the processing substrate based on the voltage and the current applied to the electrostatic chuck mechanism and the impedance value representing the electric property of the electrostatic chuck mechanism stored in the impedance value storage means; andthe apparatus further comprises a control unit for generating a control signal for the bias voltage applying means and providing the same to the bias voltage applying means based on the estimated voltage value of the processing substrate estimated via the means for estimating the voltage value of the processing substrate.

4. The plasma processing apparatus according to claim 1, wherein the waveform of the bias voltage value of the processing substrate is controlled so as to planarize a sag in the voltage of the processing substrate.

5. A plasma processing method for subjecting a processing substrate to plasma processing, the method comprising: storing a processing substrate in a processing chamber, attracting and supporting the processing substrate electrostatically on an electrostatic chuck mechanism of a substrate electrode, providing plasma to the processing substrate from a plasma generating means, and supplying bias voltage to the processing substrate on the substrate electrode from a bias voltage applying means; further comprisingacquiring an impedance value of the electrostatic chuck mechanism by measuring a voltage of a processing substrate for measurement placed on the substrate electrode, and using a capacity component of the electrostatic chuck mechanism, the bias voltage applied to the electrostatic chuck mechanism and a bias current flowing through the electrostatic chuck mechanism, and storing the acquired impedance value of the electrostatic chuck mechanism in an impedance value storage means; andestimating the voltage of the processing substrate to be subjected to plasma processing using the bias voltage value and the bias current value applied to the processing substrate actually subjected to plasma processing, and using the acquired impedance value of the electrostatic chuck mechanism.

6. The plasma processing method according to claim 5, further comprising controlling a power supply output of the bias voltage applying means through use of an estimated potential of the processing substrate.

7. The plasma processing method according to claim 5, further comprising controlling the waveform of the bias voltage value of the processing substrate so as to planarize a sag in the voltage of the processing substrate.

8. The plasma processing method according to claim 5, wherein the impedance value storage means takes in and stores the bias voltage and the bias current applied to the electrostatic chuck mechanism, and further stores the impedance value representing the electric property of the electrostatic chuck mechanism;the means for estimating the voltage value of the processing substrate estimates the voltage value of the processing substrate based on the voltage and the current applied to the electrostatic chuck mechanism and the impedance value representing the electric property of the electrostatic chuck mechanism stored in the impedance value storage means; andthe method further comprises generating a control signal for the bias voltage applying means and providing the same to the bias voltage applying means via a control unit based on the estimated voltage value of the processing substrate estimated by the means for estimating the voltage value of the processing substrate.