JP2887266B2 - Plasma CVD equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a capacitively coupled plasma C
It relates to a VD device.

[0002]

2. Description of the Related Art Plasma CVD apparatuses are used in the manufacture of various products including the manufacture of semiconductor elements, and are widely used, for example, in the manufacture of electrophotographic photosensitive members having an amorphous silicon film. ing. Among the plasma CVD apparatuses, the capacitively-coupled type can uniform the thickness distribution to be formed, easily control the conditions for changing the film formation rate, and can relatively increase the film formation rate. ,
More often than inductively coupled. FIG.
Shows an example of a conventional capacitively coupled plasma CVD apparatus. Reference numeral 1 denotes a reaction chamber in which a cylindrical substrate 2 rotated by a motor 8 is placed as an electrode, and a hollow counter electrode 3 made of a rigid metal provided with a group of gas ejection holes 6.
Is installed so as to face and surround the drum-shaped substrate. The outside is covered with a shield plate 7 made of metal. The source gas is introduced from the cylinder 4 by the introduction pipe 5, causing glow discharge to deposit and form a film on the cylindrical substrate 2. 9 is an RF power supply, and 10 is an exhaust system.

[0003] By the way, such a capacitively coupled plasma C
In a VD apparatus, when the film forming speed is increased and the film is formed for a long time, the radicals formed by the glow discharge increase, and they are aggregated into fine particles, further aggregated into giant particles, It is deposited on the electrode surface. Of the deposits, powdery ones easily fall off, adhere as fine powders, and are taken into the film to deteriorate the performance of the film.
In order to solve such a problem, an electrode facing the substrate may be provided with a large number of holes (Japanese Patent Laid-Open No. 2-10 / 1990).
It is known that a wire mesh is brought into contact with the surface of the opposing electrode to cover it (Japanese Patent Application Laid-Open Nos. 59-193265 and 59-193266).

[0004]

In the prior art, the deposit on the counter electrode on the gas inflow side becomes a film and is difficult to peel off. There was a problem that the amount of the powdery deposit on the counter electrode increased. This powdery deposit is easily peeled off and scattered from above the counter electrode, and deteriorates the performance of the formed film. Therefore, the above-mentioned conventional technique has not been said to be sufficient yet. Accordingly, an object of the present invention is to provide a capacitively coupled plasma CVD apparatus capable of suppressing generation of powdery deposits to a very low level. Another object of the present invention is to use the film continuously or repeatedly for a long time without deteriorating the performance of a film to be formed, which can increase a film forming rate, and does not deteriorate the performance of a film to be formed due to peeling or scattering of a deposit. It is an object of the present invention to provide a plasma CVD apparatus capable of performing the above.

[0005]

Means for Solving the Problems Plasma CVD of the present invention
Device includes a substrate and a counter electrode in the vacuum chamber, the electrode, consisted of a tubular outer electrode and an inner electrode
The outer and inner electrodes surround each other so as to surround the substrate.
The outer electrode and the inner electrode are connected so that they are at the same potential , and are connected to one side of the outer electrode.
The gas is blown out between the outer electrode and the inner electrode.
An inlet is provided and a gas outlet on the other side of the outer electrode
Is provided, and the inner electrode consists of a porous plate having a pore size of 2 mm to 8 mm, the distance between the inner electrode and the outer electrode, characterized in that a 2 mm to 30 mm. Further, a shield plate may be further provided outside the outer electrode.

Hereinafter, a plasma CVD apparatus according to the present invention will be described with reference to FIG. In the plasma CVD apparatus of the present invention, a counter electrode composed of an outer electrode 11 and an inner electrode 12 is disposed in a reaction chamber 1 composed of a vacuum chamber, facing a cylindrical substrate 2, and these electrodes are electrically connected by means not shown. And are held at the same potential. The outer electrode has a gas inlet 13 and a gas outlet 1
4 are provided.

[0007] The inner electrode 12 is constituted by a perforated plate having a fixed hole diameter. This perforated plate has a diameter of 2 mm to 8 mm.
It is necessary to provide pores in the range of mm ,
It is preferable that they are provided side by side in a fixed arrangement in the range of 10% to 70% of porosity. Because the hole diameter is 2m
If it is smaller than m, the holes will be blocked during the film formation, and the film formation speed will be significantly reduced. Also, 8mm
If it is larger than this, abnormal discharge occurs in the pores, and powdery deposits adhere to the outer electrode. When the porosity is lower than 10%, powdery deposits are generated in portions other than the holes, and when the porosity is higher than 70%, powdery deposits are generated on the outer electrode. Occur.

The distance between the inner electrode and the outer electrode is 2 m
set in the range of m to 30 mm , especially 3 to 15 mm
Is preferable. 2 mm gap between inner and outer electrodes
If the thickness is smaller than the above range, the gap is filled with the powdery deposit and the film deposited on the outer electrode during the film formation, and the gas does not flow uniformly through the inner electrode, resulting in poor film thickness distribution.
On the other hand, when it is larger than 30 mm, powdery deposits are generated on the outer electrode, and the film quality is deteriorated.

[0009]

The source gas introduced from the gas inlet 13 is decomposed by the glow discharge between the counter electrode and the cylindrical substrate 2 to form a film on the substrate. In this case, since the inner electrode 12 made of the above-mentioned perforated plate is provided between the outer electrode 11 of the counter electrode and the substrate 2, the source gas introduced from the gas inflow port causes Flows between
It gradually flows out of the hole of the inner electrode into the plasma space. Therefore, the film forming conditions for forming a hard film near the gas inflow side in the conventional plasma CVD apparatus are:
Therefore, the deposit on the counter electrode becomes a hard film having a strong adhesive force, and the formation of a powdery deposit having a weak adhesive force is almost eliminated.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of the plasma CVD apparatus of the present invention, and FIG. 2 is a cross-sectional view taken along line AA of FIG.
FIG. 3 is a schematic configuration diagram of the whole plasma CVD apparatus of the present invention. A pedestal rotatable by a motor 8 is provided in the reaction chamber 1, and a cylindrical substrate 2 is mounted thereon. A cylindrical counter electrode composed of an outer electrode 11 and an inner electrode 12 is disposed so as to face the substrate 2 and surround the same. The outer electrode 11 is provided with a group of gas ejection holes 6 on one side and a group of gas exhaust holes 15 or slits on the other side so that the gas is discharged from the gas outlet 14. I have. Also, the inner electrode 12
The outer electrode 1 is constituted by a perforated plate,
1 and is electrically connected and fixed.

A case in which silane gas is used as a source gas will be described. The silane gas in the cylinder 4 placed outside the reaction chamber is introduced from the gas inlet 13 and is ejected from the gas ejection hole group 6 between the outer electrode and the inner electrode. Next, the gas is ejected from the hole of the inner electrode 12 into the space between the inner electrode and the substrate. The outer electrode and the inner electrode are electrically connected and maintained at the same potential, and they are supplied with capacitively-coupled power by an RF power supply 9.

(Example 1) The diameter of the outer electrode is set to 180 mm, the diameter of the inner electrode is set to 160 mm, and the distance between both is set to 10 mm.
Further, a plasma CVD apparatus having a configuration in which holes having a diameter of 4 mm are formed at equal intervals on the entire surface of the inner electrode so as to have a porosity of 50% is formed on an aluminum substrate having a diameter of 120 mm. A 20 μm amorphous silicon film was formed. When a film was formed under the conditions of a silane gas flow rate of 300 sccm, a pressure of 1.0 Torr, and an RF output of 300 W, almost no powdery deposit was formed on the outer and inner electrodes. Therefore, the formed electrophotographic photoreceptor provided an image with excellent image quality without image defects.

(Comparative Example 1) A test was performed under the same discharge conditions as described above except that the diameter and the hole diameter of the inner electrode were changed as shown in Table 1 below, and the results shown in Table 1 were obtained. .

[0014]

[Table 1]

(Example 2) The diameter of the outer electrode is 180 mm, the diameter of the inner electrode is 120 mm, and the distance between the two is 30 mm.
A film was formed on the inner electrode under the same conditions as in Example 1 using a plasma CVD apparatus having a configuration in which holes having a diameter of 5 mm were formed at equal intervals over the entire surface so as to have a porosity of 50%. As a result, film-like deposits adhered on the outer and inner electrodes, and powder-like deposits were hardly formed.

Example 3 A film was formed in the same manner as in Example 1 except that the inner electrode was a cage type as shown in FIG.
A film-like deposit adhered to the outer electrode and the inner electrode, and almost no powder-like deposit was formed.

(Comparative Example 2 ) For comparison, a process was performed under the same film forming conditions as in Example 1 except that the inner electrode was not provided in the plasma CVD apparatus of Example 1, and the inner surface of the inner electrode was entirely exposed. A brown powdery deposit adhered to the surface. When copying was performed using the formed electrophotographic photoreceptor, the obtained copy image had image quality with image defects.

(Comparative Example 3 ) In the plasma CVD apparatus of Example 1, processing was performed under the same film forming conditions as in Example 1 except that the outer electrode was removed and no electrode was provided. Of powdery deposits. When copying was performed using the formed electrophotographic photoreceptor, the obtained copy image had image quality with image defects.

[0019]

According to the plasma CVD apparatus of the present invention, as described above, the counter electrode has a double structure.
By disposing the inner electrode and the outer electrode apart from each other and using the inner electrode as a perforated plate electrode, it is possible to prevent the generation of powdery deposits that are liable to peel off or fall off. Therefore, according to the present invention, the film formation rate can be increased by, for example, 50% or more as compared with the conventional technique, and the performance of the formed film is deteriorated due to the separation or detachment of the deposit. And can be operated continuously or repeatedly for a long time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an embodiment of a main part of a first plasma CVD apparatus of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic configuration diagram of a plasma CVD apparatus of the present invention.

FIG. 4 is a perspective view of an embodiment of the inner electrode of the present invention.

FIG. 5 is a schematic configuration diagram of a conventional plasma CVD apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reaction chamber, 2 ... Substrate, 3 ... Hollow counter electrode, 4 ... Cylinder, 5 ... Inlet tube, 6 ... Gas ejection hole group, 7 ... Shield plate,
8 motor, 9 RF power supply, 10 exhaust system, 11 outer electrode, 12 inner electrode, 13 gas inlet, 14 gas outlet, 15 gas exhaust hole group.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Joe Fukuda 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. Takematsu Office (56) References JP-A-3-44474 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) C23C 16/00-16/56

Claims (1)

(57) [Claims] To 1. A vacuum chamber in the plasma CVD apparatus having a substrate and a counter electrode, the electrode is composed of a cylindrical outer electrode and the inner electrode, the outer electrode and the inner electrode groups
Are disposed apart from each other so as to surround the plate, it is connected to the outer electrode and the inner electrode at the same potential, the outer electrode one
Spout gas between outer electrode and inner electrode on one side
A gas inlet is provided so that the other side of the outer electrode
Gas outlet is provided and inner electrode is 2mm
A plasma CVD apparatus comprising a perforated plate having a hole diameter of up to 8 mm, and wherein a distance between an inner electrode and an outer electrode is 2 mm to 30 mm.