JPH08124864A - Vacuum plasma treating apparatus - Google Patents

Abstract

PURPOSE: To increase the plasma density on a sample substrate, while keeping the plasma uniform. CONSTITUTION: The title apparatus has a vacuum vessel 1, vacuum pump 2, reactive gas feed hole 3, susceptor 5 for holding a sample substrate 4 in the vessel 1, high frequency power source 6 for the susceptor 5, split electrodes 7a-7c, and high frequency power sources 8a-8c for applying phase-different high frequency powers to the electrodes 7a-7c. The vessel has a part facing at the susceptor 5, this part is composed of an insulator-made dome-like wall 11 on which the electrodes 7a-7c are disposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum plasma processing apparatus for performing dry etching, sputtering, plasma CVD and other surfaces on a substrate to be processed such as a semiconductor wafer and a liquid crystal display substrate.

[0002]

2. Description of the Related Art Conventionally, a wall surface electrode type and a hanging electrode type are known as a vacuum plasma processing apparatus for generating high-frequency power having different phases by applying high frequency powers to divided electrodes.

A wall electrode type plasma processing apparatus is, for example, a "Lissajous Electron Plasma".
a (LEP) Generation for Et
ching "Jpn.J.Appln.Phys.Vo
l. 31 (1992) pp. 4332-4337 "
Is disclosed in. The hanging electrode type has a mechanism in which a local discharge does not occur between the electrode end and the inner wall of the vacuum container, and is disclosed in Japanese Patent Laid-Open No. 5-180002.

A configuration example of the wall electrode type will be described with reference to FIGS. 6 and 7. A susceptor 25 holding a substrate 24 to be processed is disposed in a vacuum container 21 having a vacuum pump 22 and a reaction gas supply port 23, and a high frequency power supply 26 is connected to the susceptor 25. Three flat plate type divided electrodes 2 are provided on the wall surface of the vacuum container 21 via a spacer 29 made of an insulator.
7a to 27c are arranged, and the divided electrodes 27a to 27c have high frequency power sources 28a to 2c having different phases of about 120 °.
8c is connected.

A structural example of the hanging electrode type will be described with reference to FIGS. 8 and 9. Vacuum pump 32 and reaction gas supply port 3
A susceptor 35 for holding a substrate to be processed 34 is disposed in a vacuum container 31 having a high frequency power source 36 connected to the susceptor 35. Above the susceptor 35, three arc-shaped divided electrodes 37a to 37c are arranged in a cylindrical shape as a whole, and each divided electrode 37a to 37c is connected to a high frequency power source 38a to 38c having a phase difference of about 120 °. ing.

Next, the operation of the vacuum plasma processing apparatus having the above-described structure will be described. While the vacuum containers 21 and 31 are evacuated by the vacuum pumps 22 and 32, the reaction gas is supplied from the reaction gas supply ports 23 and 33. It is introduced into 21, 31 and kept at an appropriate pressure. Next, the high frequency power supply 2 is applied to the three divided electrodes 27a to 27c and 37a to 37c.
8a to 28c and 38a to 38c apply high frequency power having a phase difference of about 120 ° to each other.
An electric field is generated inside. Electrons are accelerated by this electric field, and plasma is generated. On the other hand, the susceptors 25 and 35
The high-frequency power sources 26 and 36 connected to the substrate 2 to be processed 2
A bias potential is generated at 4, 34. Then, the ions in the plasma are made incident on the substrates 24 and 34 to be processed, and the substrates 24 and 34 are surface-treated.

[0007]

However, as shown in FIG.
In the configuration of the wall electrode type of FIG. 7, the divided electrodes 27a to 27c
There is a problem that abnormal discharge is likely to occur between the vacuum container 21 and the vacuum container 21 and the uniformity of the electric field is low.

Further, in the structure of the hanging electrode type shown in FIGS. 8 and 9, since the local discharge is unlikely to occur, the substrate to be processed 34 is processed.
However, plasma is also generated between the divided electrodes 37a to 37c and the vacuum container 31, resulting in power loss and a decrease in plasma density on the substrate 34 to be processed. There is a problem.

In any of the above constructions, the split electrode 2 is used to enhance the electric field strength and plasma density.
In order to increase the area of 7a to 27c and 37a to 37c, the divided electrodes 27a to 27c and 37a to 37c must be extended in a direction away from the substrates 24 and 34 to be processed. There is a problem that the active species generated at a distant position do not contribute effectively to the surface treatment and are not effective.

In view of the above conventional problems, it is an object of the present invention to provide a vacuum plasma processing apparatus capable of increasing plasma density on a substrate to be processed while maintaining plasma uniformity. .

[0011]

A vacuum plasma processing apparatus according to the present invention comprises a vacuum container, a means for evacuating the inside of the vacuum container, a means for supplying a reaction gas into the vacuum container, and an object to be processed in the vacuum container. A susceptor for holding the substrate, means for applying high-frequency power to the susceptor, divided electrodes arranged facing the substrate to be processed, and a power supply device for applying high-frequency power with different phases to the divided electrodes In the above vacuum plasma processing apparatus, the portion of the vacuum container facing the susceptor is formed of a dome-shaped wall made of an insulator, and the divided electrodes are arranged on the dome-shaped wall.

The divided electrodes are arranged by fitting them into an electrode mounting window formed on the dome-shaped wall surface, and the surface facing the inside of the vacuum container is formed into a convex spherical surface, a concave spherical surface or a flat surface, or arranged on the outer surface of the dome-shaped wall surface. To be done.

[0013]

According to the present invention, since the portion of the vacuum container facing the susceptor is constituted by the wall surface made of a dome-shaped insulator, it is possible to prevent local discharge and deteriorate plasma uniformity. By applying high-frequency power with different phases to the divided electrodes arranged on the dome-shaped wall surface, the electrode of each divided electrode can be changed without significantly changing the distance to the substrate to be processed on the susceptor. The size of the surface can be increased, the electric field strength can be increased while maintaining the uniformity of the plasma, and the plasma density can be improved, and the increased active species contributes effectively to the surface treatment. Can be made. In addition, by applying high-frequency power to the susceptor that holds the substrate to be processed, it is possible to independently control the ion energy that reaches the substrate to be processed, causing damage to the substrate while generating high-density plasma. You can avoid it.

Further, by disposing the divided electrodes by fitting them into the electrode mounting window formed on the dome-shaped wall surface and by forming the surface facing the vacuum container into a convex spherical surface, the electric field between the electrodes can be made uniform,
The concave spherical surface maximizes the plasma volume and facilitates cleaning, and the flat surface facilitates production of the divided electrodes.

When the divided electrodes are arranged on the outer surface of the dome-shaped wall surface, the plasma distribution can be adjusted by adjusting the position, and the divided electrodes are not sputtered, so that clean plasma can be generated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vacuum plasma processing apparatus according to an embodiment of the present invention will be described below with reference to FIGS.

The vacuum container 1 is constructed by joining a dome-shaped wall surface 11 made of an insulator to the upper part of the lower body wall surface 10. A vacuum pump 2 is provided below the vacuum container 1, and a reaction gas supply port 3 is provided at the top of the dome-shaped wall surface 11. A susceptor 5 that holds the substrate 4 to be processed is disposed in the lower portion of the vacuum container 1. A high frequency power source 6 for controlling ion energy is connected to the susceptor 5.

The dome-shaped wall 11 has three divided electrodes 7
a, 7b, 7c are arranged at an interval of 120 ° from each other. These divided electrodes 7a, 7b, 7c are fitted by being fitted into an electrode fitting window 11a formed on the dome-shaped wall surface 11, and the surface facing the vacuum container 1 is formed as a convex spherical surface. Further, the divided electrodes 7a, 7b, 7c are connected to high frequency power supplies 8a, 8b, 8c for generating plasma 9. The high frequency power supplies 8a, 8b and 8c are out of phase with each other by about 120 °.

Next, the operation of the vacuum plasma processing apparatus having the above configuration will be described. Vacuum pump 2 inside the vacuum container 1
While being evacuated, the reaction gas is introduced from the reaction gas supply port 3 and maintained at an appropriate pressure. Then, the divided electrodes 7a, 7b, 7c are respectively provided with high frequency power supplies 8a, 8b,
High-frequency powers having different phases of about 120 ° are applied from 8c, and plasma 9 is generated in the upper space of the vacuum container 1 surrounded by the dome-shaped wall surface 11. At that time, since the portion of the vacuum container 1 facing the susceptor 5 is formed by the dome-shaped wall surface 11 made of an insulator, the divided electrodes 7a, 7
b, 7c and the vacuum vessel 1 can be prevented from being locally discharged to prevent deterioration of plasma uniformity, and the divided electrodes 7a, 7b and 7c are disposed on the dome-shaped wall surface 11. Therefore, the divided electrodes 7a, 7b, 7c can be formed on the susceptor 5 without significantly changing the distance to the substrate 4 to be processed.
The size of the electrode surface can be increased, the electric field strength can be increased while maintaining plasma uniformity, and the plasma density can be improved, and the increased active species can be effectively contributed to the surface treatment. Therefore, uniform processing can be performed at high speed.

Further, by arbitrarily applying high-frequency power from the high-frequency power source 6 to the susceptor 5, the ion energy of the plasma 9 incident on the substrate 4 to be processed is controlled, and optimum vacuum plasma processing can be performed.

The surfaces of the divided electrodes 7a, 7b, 7c facing the dome-shaped wall surface 11 are convex spherical surfaces, which has the effect of making the electric field between the electrodes uniform.

Next, the second embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Only different points will be described. The same applies to the following examples. In this embodiment, instead of the divided electrodes 7a, 7b, 7c, divided electrodes 12a, 12b, 12c whose surfaces facing the inside of the vacuum chamber 1 are formed into concave spherical surfaces are provided. According to this embodiment, the volume of plasma can be maximized and the inner surface of the vacuum container 1 can be easily cleaned.

Next, the third embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In this embodiment, the divided electrodes 7a, 7
Instead of b and 7c, split electrodes 13a, 13b and 13c are provided, the surfaces of which face the interior of the vacuum container 1 are formed flat. According to this embodiment, the divided electrodes can be easily manufactured.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. In this embodiment, the dome-shaped wall surface 11
Instead of the divided electrodes 7a, 7b, 7c fitted into the electrode mounting window 11a formed in the above, the divided electrodes 14a, 14b, 14c are provided on the outer surface of the dome-shaped wall surface 11. According to this embodiment, the divided electrodes 14a, 14b, 1
4c can be arranged at any position to adjust the plasma distribution, and the split electrode 1 into the vacuum chamber 1
Clean plasma 9 can be generated without the sputtering of 4a, 14b, and 14c.

[0025]

According to the vacuum plasma processing apparatus of the present invention, as is clear from the above description, the portion of the vacuum container facing the susceptor is formed by the wall surface made of a dome-shaped insulator. It is possible to prevent local discharge and prevent deterioration of plasma uniformity, and to increase the size of the electrode surface of each divided electrode without greatly changing the distance to the substrate to be processed on the susceptor. As a result, the plasma density can be improved while maintaining the plasma uniformity, and the increased active species can be effectively contributed to the surface treatment, which enables uniform surface treatment at high speed. Become. In addition, by applying high-frequency power to the susceptor that holds the substrate to be processed, it is possible to independently control the ion energy that reaches the substrate to be processed, causing damage to the substrate while generating high-density plasma. You can avoid it.

Further, when the divided electrodes are fitted into the electrode mounting window formed on the dome-shaped wall and arranged, and the surface facing the vacuum container is formed into a convex spherical surface, the electric field between the electrodes can be made uniform,
The concave spherical surface maximizes the plasma volume and facilitates cleaning, and the flat surface facilitates production of the divided electrodes.

Further, when the divided electrodes are arranged on the outer surface of the dome-shaped wall surface, the plasma distribution can be adjusted by adjusting the positions, and the divided electrodes are not sputtered, so that clean plasma can be generated.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a schematic configuration of a vacuum plasma processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a plan view of the embodiment.

FIG. 3 is a vertical sectional front view showing a schematic configuration of a vacuum plasma processing apparatus according to a second embodiment of the present invention.

FIG. 4 is a vertical sectional front view showing a schematic configuration of a vacuum plasma processing apparatus according to a third embodiment of the present invention.

FIG. 5 is a vertical sectional front view showing a schematic configuration of a vacuum plasma processing apparatus according to a third embodiment of the present invention.

FIG. 6 is a vertical sectional front view showing a schematic configuration of a conventional vacuum plasma processing apparatus.

FIG. 7 is a cross-sectional plan view of the conventional example.

FIG. 8 is a vertical sectional front view showing a schematic configuration of another conventional vacuum plasma processing apparatus.

FIG. 9 is a cross-sectional plan view of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 vacuum container 2 vacuum pump 3 reaction gas supply port 4 processed substrate 5 susceptor 6 high frequency power source 7a to 7c split electrode 8a to 8c high frequency power source 11 dome-shaped wall surface 11a electrode mounting window 12a to 12c split electrode 13a to 13c split electrode 14a to 14c split electrode

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tokuhiko Tamaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A vacuum vessel, a means for evacuating the inside of the vacuum vessel, a means for supplying a reaction gas into the vacuum vessel, a susceptor for holding a substrate to be processed in the vacuum vessel, and high-frequency power for the susceptor. In a vacuum plasma processing apparatus including a means for applying a voltage, a split electrode arranged to face the substrate to be processed, and a power supply device for applying high-frequency power having different phases to the split electrode, facing the susceptor of the vacuum container. A vacuum plasma processing apparatus, characterized in that a portion to be formed is formed by a dome-shaped wall made of an insulator, and the divided electrodes are arranged on the dome-shaped wall. 2. The vacuum plasma processing apparatus according to claim 1, wherein the divided electrodes are arranged by being fitted into an electrode mounting window formed on a dome-shaped wall surface, and a surface facing the vacuum container is a convex spherical surface. . 3. The vacuum plasma processing apparatus according to claim 1, wherein the divided electrodes are arranged by being fitted into an electrode mounting window formed on a dome-shaped wall surface, and a surface facing the vacuum container is a concave spherical surface. . 4. The vacuum plasma processing apparatus according to claim 1, wherein the divided electrodes are fitted in an electrode mounting window formed on a dome-shaped wall surface and arranged so that the surface facing the vacuum container is a flat surface. 5. The vacuum plasma processing apparatus according to claim 1, wherein the divided electrodes are arranged on the outer surface of the dome-shaped wall surface.