JPH05291155A - Plasma processor - Google Patents

Abstract

PURPOSE:To enhance the evenness of plasma processing step within the plasma processor. CONSTITUTION:Within the plasma processor, a pair of electrodes 1, 2 oppositely arranged are respectively impressed with a high-frequency power to produce plasma for processing a work arranged on either one electrode using the plasma, both electrodes are impressed with a power in the same frequency while making the phase difference of both impressed powers controllable so that the processing performance, ion energy may be controlled by the phase difference control while controlling the plasma processing evenness and processing state thereby enhancing the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus, such as a plasma CVD apparatus or a plasma etching apparatus for a semiconductor manufacturing apparatus, which uses plasma to process an object to be processed such as a wafer.

[0002]

2. Description of the Related Art As one of semiconductor manufacturing processes, gas is turned into plasma by high-frequency power to generate ions and radicals.
There is plasma etching for etching a thin film formed on the wafer surface by al, free radicals) and plasma CVD processing for generating plasma to form a thin film on the wafer.

An outline of a conventional plasma processing apparatus will be described with reference to FIG.

Electrodes 1 and 2 for plasma generation are vacuum containers 5
High frequency power supplies 3 and 4 are connected to the electrodes 1 and 2, respectively, facing each other. By applying high-frequency power between the electrodes 1 and 2, plasma is generated between the electrodes 1 and 2, and the wafer 17 placed on the one electrode 2 is processed.

[0005]

In such a wafer processing apparatus utilizing plasma, the plasma intensity, plasma density, plasma uniformity, etc. have a great influence on the processing efficiency and processing accuracy. Therefore, various proposals have been made for improving the uniformity of plasma in the plasma processing apparatus, and the present invention aims to provide a plasma processing apparatus with improved uniformity of such plasma processing.

[0006]

According to the present invention, electrodes are arranged so as to face each other, high-frequency power is applied to each of the pair of electrodes to generate plasma, and one of the electrodes is utilized by using the plasma. A plasma processing apparatus for processing an object to be processed provided on electrodes is characterized in that electric power of the same frequency is applied to both electrodes and a phase difference between the applied powers can be controlled.

[0007]

[Operation] By controlling the phase difference of the applied power to both electrodes,
The processing performance and ion energy can be controlled, plasma processing uniformity and processing state can be controlled, and the movement of the plasma density part can be controlled by controlling the phase difference of the power applied to both electrodes while applying a magnetic field to the plasma generation region. It is possible to improve the uniformity of the plasma processing by controlling the movement of the plasma density portion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same parts as those shown in FIG. 5 are designated by the same reference numerals.

It is known that the plasma excitation efficiency is increased when the lines of magnetic force cross each other in the plasma. In the plasma processing apparatus according to this embodiment, a ring-shaped intensifying magnet 6 is provided around the vacuum container 5. The magnetic field is arranged so as to surround the generation region, and a magnetic field parallel to the upper electrode 1 and the lower electrode 2 is generated in the plasma generation space.

FIG. 2 shows a power control system in this embodiment.

The high frequency from the high frequency oscillator 7 is amplified by the power amplifier 8 and further applied to the upper electrode 1 through the impedance 9, and the high frequency from the high frequency oscillator 7 is passed through the phase shifter 10. It is input to the power amplifier 11, amplified by the power amplifier 11, and then applied to the lower electrode 2 via the impedance 12.

The phases of the high frequency power applied to the upper electrode 1 and the lower electrode 2 are input to the phase detector 13,
The phase difference between the two is input to the comparator 14. Further, a phase difference setting device 15 is connected to the comparator 14, and the phase difference 16 set and input to the phase difference setting device 15 is applied to the comparator 14
The comparator 14 inputs the deviation from the detected phase difference input from the phase detector 13 to the phase shifter 10.

The operation will be described below.

As described above, the phase detector 13 detects the phase difference of the high frequency power applied to both electrodes,
Further, the detected phase difference is compared with the set phase difference 16 by the comparator 14, and the deviation between the two is input to the phase shifter 10. The phase shifter 10 controls the phase so that the deviation becomes zero, that is, the phase difference of the high frequency power applied to both electrodes becomes the set phase difference 16. Thus, the high frequency power applied to the upper electrode 1 and the lower electrode 2 is controlled so as to match the phase difference of the set phase difference 16.

By the way, the present inventors have confirmed that the uniformity of wafer processing is changed by changing the phase of the high frequency power applied to the upper electrode 1 and the lower electrode 2, and it has been confirmed by the inventors. The relationship between the phase difference and the uniformity is shown in FIG.

By varying the phase from -180 ° to 180 °, the wafer processing uniformity varies from approximately 5% to 23%. Thus, the phase difference between both electrodes is selected as a parameter for controlling the uniformity of wafer processing, and the phase difference is controlled and adjusted to improve the uniformity of wafer processing performance.

The present inventors have also confirmed that Vdc (self-bias voltage) is changed by changing the phase of the high frequency power applied to the upper electrode 1 and the lower electrode 2.

This Vdc is related to the ion energy of plasma, and the ion energy is related to the anisotropy and selectivity of etching when a wafer is etched. Thus, by changing the phase of the high frequency power applied to the upper electrode 1 and the lower electrode 2, it becomes possible to control the ion energy, and the anisotropy in plasma processing of various different materials and the selection And wafer processing can be controlled in a static state.

As described above, by applying a magnetic field to the plasma generation region. The plasma excitation efficiency can be increased, but when the phase of the high frequency power applied to the upper electrode 1 and the lower electrode 2 is changed, the shaded portion of the plasma moves.
Further, in FIG. 1, the strengthening magnet 6 is mechanically moved, that is, vertically moved, or rotated in a horizontal plane.
Further, the dark and light part of the plasma also moves by moving the magnetic field by changing the applied state of the current flowing through the strengthening magnet 6 by using the strengthening magnet 6 as an electromagnet.

Thus, during the plasma treatment, the upper electrode 1,
The phase of the high frequency power applied to the lower electrode 2 is set from 0 ° to 3
The plasma treatment is averaged by scanning the plasma at any number up to 60 °, or by rotating the dark and light portion of the plasma by moving the magnetic field by the intensifying magnet 6 as described above. Highly uniform plasma processing over a wide range is possible.

Furthermore, it is possible to perform self-cleaning in the vacuum container 5 by utilizing the movement of the dark and light portions of the plasma.

[0023]

As described above, according to the present invention, it is possible to perform highly uniform plasma processing on a wafer over a large area and a wide range, and it is possible to improve the processing performance and quality of the plasma processing. Exerts an excellent effect.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a power control system in the embodiment.

FIG. 3 is a diagram showing the high frequency power phase difference between the upper and lower electrodes and the uniformity of plasma processing.

FIG. 4 is a diagram showing a relationship between a high frequency power phase difference between upper and lower electrodes and a self bias voltage.

FIG. 5 is an explanatory diagram showing a conventional plasma processing apparatus.

[Explanation of symbols]

 1 electrode 2 electrode 3 high frequency power supply 4 high frequency power supply 5 vacuum vessel 6 booster magnet 7 high frequency oscillator 10 phase shifter 13 phase detector 14 comparator 15 phase difference setter 16 phase difference 17 wafer

Claims (6)

[Claims] 1. An electrode is provided so as to face each other, high-frequency power is applied to each of the pair of electrodes to generate plasma, and the object to be treated is provided on either one of the electrodes by using the plasma. 1. A plasma processing apparatus for processing, wherein electric power having the same frequency is applied to both of the electrodes, and a phase difference between the applied powers can be controlled. 2. The plasma processing apparatus according to claim 1, wherein the uniformity of plasma processing is controlled by adjusting the phase difference between both applied powers. 3. The plasma processing apparatus according to claim 1, wherein the plasma ion energy is controlled by adjusting the phase difference between both applied powers. 4. The plasma processing apparatus according to claim 1, wherein a magnetic field is applied to the plasma generation region. 5. The phase difference between both applied powers is 0 ° to 360 °.
5. The plasma processing apparatus according to claim 4, wherein the plasma processing unit is configured to rotate up to a given number of times until the dark and light portions of plasma are rotated. 6. The plasma processing apparatus according to claim 5, wherein self-cleaning of the inside of the vacuum container is performed by rotating a dark and light portion of plasma.