JPS6244576A - Apparatus for treatment by electric discharge reaction with plural electrodes - Google Patents

Abstract

PURPOSE:To increase the efficiency and rate of treatment by placing plural electrodes in a vacuum vessel, regarding a high frequency voltage applied to one of the electrodes as a standard and applying a high frequency voltage having a prescribed phase difference with respect to the standard voltage to other electrode so as to generate plasma. CONSTITUTION:Plural electrodes are placed in a vacuum vessel 1 contg. an introduced prescribed gas and a high frequency voltage applied to one electrode 2 of the electrodes is regarded as a standard. A high frequency voltage having 80-280 deg. phase difference with respect to the standard voltage is applied to other electrode 3. The surface of a body 4 to be treated in the vessel 1 is subjected to prescribed treatment with plasma generated by the electric discharge.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention generates plasma by high-frequency discharge in a vacuum container, and utilizes chemical changes and sputtering of this plasma to The present invention relates to a discharge reaction processing apparatus that performs processes such as forming a thin film, etching, and surface modification on the surface of a processed object.

(Prior art and its problems) Recently, plasma CVD uses a discharge reaction.

Processing equipment such as reactive sputter etching, plasma etching, and sputtering has become widely used.

When these discharge reaction treatment devices utilize high-frequency power with multiple electrodes, conventional devices use the voltage of one electrode as a reference to examine the phase difference between the voltages of other electrodes. Most of them are within the range of ±45°.

As a result of repeated experimental studies, the inventor of the present application found that the slow processing speed and low power efficiency of this conventional device was due to an error in the selection of the phase difference value.

The purpose is to improve efficiency and processing speed.

(Structure of the Invention) The present invention provides a multi-electrode discharge reaction treatment apparatus using high-frequency power, in which the high-frequency voltage of one electrode is set to 80% higher than the reference voltage.
The above objective is achieved by maintaining the phase difference within the range of 0 to 280 degrees.

(Example) Embodiments of the present invention will be described below based on the drawings.

In the embodiment shown in FIG. 1, two electrodes, a central electrode 2 and a side electrode 3, are installed in a grounded vacuum container 1, and a predetermined gas is introduced from a waste inlet 6 through a gas cylinder and a valve (not shown). and by valves and vacuum pumps (not shown),
Gas is discharged from the gas discharge port 9, and the pressure inside the vacuum container is maintained at a predetermined value.

High-frequency power with the same frequency is supplied to the center electrode 3 from the power sources 7 and 8, and discharge plasma is generated in the vacuum container 1. The desired treatment is applied to the surface of the 5 is an insulator that supports the center electrode 2.

In the apparatus shown in FIG. 1, using CHFn+5% CO□ gas, a gas flow ffi of 1105 CCU, 800 mTo
rr pressure 1 frequency 13.56 Mllz, 150
A high frequency power of 0 W is applied to the central electrode 2, and a high frequency power of 20 W of the same frequency is applied to the central electrode 2.
A high frequency power of 0 W is supplied to the side electrode 3, and the phase of the art dealer frequency power is changed to generate S on the Si substrate 4 which is the object to be processed.
The iO□ thin film was etched to obtain the "phase difference-etching speed graph" shown in FIG.

When the phase difference of the voltage of the side electrode 3 is 0 to 60 degrees with respect to the voltage of the center electrode 2, the etching speed is 500 people/min.
1300 people/min at a phase difference of 100°
, 3,800 people/min at 140°, 3,400 people/min at 180°, 900 people/min at 220°, etc., and the vertical phase difference is from 80° to 280°.
It was confirmed that the etching speed becomes extremely slow unless the range is set to .

Differences occurred depending on the waveform of the high-frequency power and other conditions, but the most stable processing was possible when the phase difference was around 120°. In the above, the high frequency power of the central electrode 2 is 2
000W, the high frequency power of the side electrode 3 is 250W, and the phase difference is 120°, 5000 people/min under a pressure of 500 mTorr or less, 1000m100O
It was possible to obtain a high etching rate of 1 μm/min under a pressure of 1 μm/min.

Conventionally, when applying high frequency power to two electrodes from two independent power sources as shown in FIG. 1, voltages with a phase difference of 0 to 30 degrees are simply applied through a matching circuit. For this reason,
The etching rate remains at a fairly low value as seen in Figure 3. In contrast, in the present invention, the above-mentioned phase difference is realized using a high frequency power source that can control the phase of the output voltage.

It is not yet clear why the characteristics shown in FIG. 3 change when the phase difference is changed. The self-bias value of the electrode is 1
It is assumed that the reason for the large etching is that the phase difference becomes the largest in the range of 20° to 180°.

In the embodiment shown in FIG. 2, the side electrodes 3 of the device shown in FIG.
31, 32), connected to a common high-frequency power source 8, and with objects 41 and 42 placed on both side electrodes, the same results as the apparatus shown in FIG. 1 can be obtained.

The same applies when three or more side electrodes are installed on the side surface of the vacuum vessel 1 around the center electrode 2. FIG. 4 shows an embodiment of the present invention in a three-electrode sputtering device. Electrodes 13, 23 are arranged symmetrically within the vacuum vessel 1, and a ground electrode 33 is placed opposite them. A target electrode 14.24 is placed on the electrode 13.23, and a ground electrode 33
A substrate to be processed 34 is placed on top.

High frequency power from high frequency power source 17.18 to electrode 13.23
By keeping the phase difference in the range of 80° to 280°, a high and efficient processing speed (in this case, the thin film deposition speed) can be achieved.

When removing Targera 14.24 using the apparatus shown in FIG. 4, it is possible to use this apparatus as a plasma CVD apparatus. The object to be treated at that time is the electrode 13.23
It can also be taken as an example.

(Effects of the Invention) As described above, the present invention has the effect of realizing significantly higher efficiency and higher speed processing than the conventional method in a multi-electrode discharge reaction processing apparatus that uses high-frequency power.

Brief explanation of LtU plane

[Brief explanation of drawings]

FIG. 1 is a sectional view of a two-electrode discharge reaction treatment apparatus according to an embodiment of the present invention. FIG. 3 is a graph of phase difference versus etching speed obtained with the apparatus shown in FIG. FIG. 2 and FIG. 4 are sectional views of different embodiments. 1 vacuum vessel, 2 central electrode. 3 side electrode, 4 object to be treated. 5 Insulator, 6 Gas inlet. 7.8 High frequency power supply. 9 Gas discharge port FIG, 1 FIG, 2 FIG, 3 Procedural amendment (voluntary) 9JJ21, 1980

Claims (1)

[Claims] A predetermined gas is introduced into a vacuum container equipped with a plurality of electrodes, high-frequency power is supplied to those electrodes to generate plasma, and this plasma is used to control the surface of the workpiece placed in the vacuum container. In a multi-electrode discharge reaction treatment device that performs a predetermined process on a plurality of electrodes, the high-frequency voltage applied to one of the plurality of electrodes is the reference voltage, and the high-frequency voltage applied to the other electrodes is equal to the reference voltage. A multi-electrode discharge reaction treatment device characterized by having a phase difference of 80° to 280°.