JPS5938375A - Plasma cvd device - Google Patents

Abstract

PURPOSE:To deposit uniformly a photosensitive film, etc. having good reproducibility on a base body, by forming a cylindrical electrode for forming a vacuum chamber into a double-walled construction to form a gas chamber, and opening many holes for releasing a gaseous raw material in parallel arrays on the surface of the electrode wall. CONSTITUTION:A cathode electrode 1 for forming a part of a vacuum chamber 3 is made into a double-walled construction to form a gas chamber in the electrode. Plural arrays of holes 11 for releasing a gaseous raw material are formed to the inside wall on the chamber 3 side along the central axis. A cylindrical base body 2 is set in the chamber 3 and while the base body is rotated, the gaseous raw material is supplied through a gas supply pipe 6 into the chamber 3. The gaseous raw material is filled once in the gas chamber and is then released through the respective holes 11 toward the body 2. A photosensitive drum for electrophotography, etc. are stably mass-produced by the above-mentioned device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plasma CVD apparatus for forming a deposited film on a substrate.
A plasma CVD apparatus which can be used for continuous production and in particular for the continuous production of photoreceptor drums by depositing an amorphous silicon film on the surface of a cylindrical substrate using plasma CVD technology - and also within the same reaction chamber. Silicon nitride (Si
N) membrane, silicon oxynitride (5soN)
A film, a silicon oxide (8102) film, and a silicon carbide (StC) film are continuously deposited on the surface of the photoreceptor drum to improve the charging characteristics of the photoreceptor drum and to improve the moisture resistance and wear resistance of the photoreceptor drum surface. The present invention relates to a plasma CVD apparatus that also makes it possible to improve characteristics.

In the following explanation, the present invention will be mainly explained with reference to an embodiment in which the substrate on which the deposited film is formed is a cylindrical substrate for electrophotography, but the present invention apparatus uses a rectangular substrate on a cylindrical counter electrode. Arranged to form a rectangular shape, it can also be used for the purpose of depositing an amorphous photoreceptor film or an amorphous semiconductor film for arithmetic elements, and can also be used as a mold.

By depositing an ultra-hard film on the surface of tools that are prone to wear, such as bits, it can be used to improve wear resistance and extend the life of tools.

A typical example of such a conventional cylindrical plasma CVD apparatus is schematically shown in FIG. In Fig. 1, 1 is a cylindrical cathode electrode constituting a vacuum chamber, and 2 is an anode electrode that is a counter electrode arranged concentrically with the vacuum chamber so as to rotate around the central axis of the vacuum chamber. 3 is the upper and lower walls of the vacuum chamber;
4 is a donut-shaped insulator that insulates the wall from the cathode electrode, 5 is a high frequency power source, 6 is a raw material gas supply pipe, 7 is an exhaust system, 8 is a heater, and 9 is the cylindrical insulator mentioned above. A rotation mechanism for rotating the base body, 10 is a ground, and 11 is a raw material gas discharge hole.

The operation of the above plasma CVD apparatus will be briefly explained.

First, a cylindrical base 2 is set in a vacuum chamber,
The inside of the chamber is evacuated by the exhaust system 7. At the same time, the base body 2 is heated by the heater 8, and the base body 2 is rotated by the rotation mechanism 9, thereby making the temperature distribution of the base body uniform. At this time,
The heater is fixed. When the temperature of the substrate becomes constant, raw material gas is supplied into the vacuum chamber from the gas supply pipe f6. The raw material gas is discharged toward the substrate 2 from the numerous gas discharge holes of the cylindrical electrode. With gas being stably supplied into the vacuum chamber, a high frequency voltage is applied to the cathode electrode 1 by a 13.56 MHz high frequency power source 5 to generate a glow discharge between the grounded bases 20 and from the cathode electrode. The collision of the ejected electrons with the gas molecules causes the gas molecules to undergo a radical reaction and is deposited on the substrate, forming a deposited film, for example, an amorphous silicon film, on the substrate 2.

In the above-mentioned plasma CVD apparatus, the thickness distribution of the deposited film depends on the position of the exhaust port of the apparatus, the flow rate of the raw material gas, the film deposition rate depending on the magnitude of high-frequency power during discharge, the degree of vacuum, and the raw material. Varies depending on the position of the gas release hole.

Considering the purpose of using an amorphous silicon photoreceptor film, uniformity of the film thickness distribution over a wide range is required on a large area substrate.

In a plasma CVD apparatus, the gas flow rate, the magnitude of high-frequency power, the degree of vacuum, etc. affect the film flexibility, and therefore cannot be used as means for adjusting the film thickness distribution. It is also difficult to freely change the position of the exhaust port due to the device configuration. That is, as a method for adjusting the film thickness distribution, adjusting the hole diameter and position of the gas discharge hole is considered to be the easiest means.

On the other hand, in plasma CVD equipment, it is necessary to select the gas flow rate and flow rate in order to obtain specific film characteristics, and the film thickness distribution also changes each time, so there is a degree of freedom in selecting the hole diameter and position of the gas release hole. It is required to be high. Most conventional cylindrical wall discharge type plasma CVD apparatuses have many irregularly opened raw material gas discharge holes or many rows of openings in the direction of the rotation axis. It was difficult to select the optimal hole position for uniform thickness distribution. Furthermore, since little consideration was given to the degree of freedom of the hole diameter, adjustment of the film thickness distribution relied only on the selection of hole positions. For this reason, the present invention has the disadvantage that it becomes difficult to adjust the film thickness distribution in proportion to the wider range of effective rights.
In addition to eliminating the drawbacks of VD equipment, plasma C
This is intended to significantly improve the film thickness distribution adjustment in VD equipment, and its feature is that raw material gas discharge holes are formed on the wall of the cylindrical core electrode in a row parallel to the central axis of the electrode. The cylindrical electrode has a double-walled structure, and a gas chamber is formed between the electrodes by providing a large number of openings. However, by arranging 1 to 10 rows of gas release holes opened in the cathode's extreme wall surface in proportion to the surface area of the substrate, and by limiting the number of openings to an extent that does not cause problems in film thickness distribution, the film thickness distribution and gas release holes can be improved. This makes it possible to clarify the correlation with the opening position of the substrate, making it possible to easily adjust the film thickness distribution, and by rotating the base body around the central axis, it is possible to ensure uniform film thickness. Furthermore, fine adjustment of the film thickness distribution is possible by drilling a screw hole in the gas release hole and providing a screw with a different hole diameter to attach it to the hole. This enables uniform deposition of a silicon photoreceptor film.

The present invention will be described in detail below based on an example device.

FIG. 2 shows a first embodiment of a plasma CVD apparatus according to the present invention. In the figures, parts similar to those in the apparatus shown in Figure 1 are designated by the same reference numerals.In the figures, 1
2 is a cylindrical cathode electrode constituting a vacuum chamber; 2 is a cylindrical base body constituting an anode electrode arranged concentrically with the central axis of the vacuum chamber; 3 is the cathode; A wall body forming a vacuum chamber above and below the electrode, 4 a donut-shaped insulating insulator for insulating the wall body from the cathode positive electrode, 5 supplying high frequency power to the cathode positive electrode and emitting glow 'FL71! - A high-frequency power supply to wake up, 6 a raw material gas supply pipe, 7 an exhaust system to keep the vacuum chamber in a vacuum, 8 a heater to heat the cylindrical base, 9 to rotate the cylindrical base. Rotating mechanism for making the thickness of the deposited film uniform, 1
0 indicates a ground, 11 indicates a raw material gas discharge hole, and 12 indicates a motor for rotating the cylindrical base body.

The cathode electrode 1 is constructed as a cylindrical double-walled structure that also serves as a part of the vacuum chamber, and a gas chamber is entirely formed within the electrode. A large number of raw material gas discharge holes 11 are opened in four rows along the axial direction. Each raw material gas release hole 1
1 is threaded, so that when adjusting the thickness distribution of the film deposited on the surface of the cylindrical substrate, unnecessary holes can be plugged with the screws. A gas release port is provided in the center of the screw that is installed in the screw hole, and by installing screws with different hole diameters in the screw hole, the amount of gas released can be changed and the film thickness distribution can be adjusted. .

FIG. 3 shows a cross section of a cylindrical double structure cathode positive electrode of a plasma CVD apparatus according to the first embodiment of the present invention. In the figure, 1 m is the atmospheric side wall surface of the cathode positive electrode, and 1 m is the dust.
b is a vacuum side wall surface with gas release holes, and 11 is a threaded raw material gas release hole opened at equal intervals.

Figures 4(a) and 4(b) show hexagon socket head screws to be attached to the gas discharge hole of the above device. In FIG. 4(A), 13 is a hexagonal socket screw with a gas discharge port, 14 is a gas discharge port, and by replacing the screw with a different hole diameter of the gas discharge port 14, the amount of gas released can be changed. Film thickness can be controlled. ◎ Figure 4 ←) 15 is a hexagon socket head screw without a gas discharge port, and is used to close the gas discharge port that is no longer needed when adjusting the film thickness distribution.

Next, the operation of each part of the above device will be explained in order.

First, a cylindrical base 2 is set in a vacuum chamber,
The inside of the chamber is evacuated by the exhaust system 7. At the same time, the base 2 is heated by the heater 8, and the base 2 is heated by the motor 1.
It is rotated by a rotating shaft connected to 2 to make the temperature distribution of the substrate uniform. At this time, the heater is fixed. When the substrate temperature becomes constant, raw material gas is supplied into the vacuum chamber from the gas supply vibro. The source gas is sent to a gas chamber within the cathode electrode 1 surrounded by a cylindrical double wall. ζWhere is the gas supply? Since the IG 6 is installed in the middle of the row of gas discharge holes 11, the raw material gas sent to the gas chamber is not directly discharged from the gas discharge holes, but is once filled in the gas chamber and then released from each gas discharge hole into the base. It is released towards the target. The amount of gas released from each discharge hole is controlled by the diameter of the gas discharge port drilled in the screw attached to the discharge hole. 13.56 when gas is stably supplied to the vacuum chamber. A high frequency voltage is applied to the cathode electrode 1 by the vIHzO high frequency power supply 5, a glow discharge is generated between the earthed base 2, and the electrons ejected from the cathode electrode collide with the gas molecules, causing the gas molecules to A radical reaction is caused to deposit on the substrate to form a deposited film such as an amorphous silicon film.

FIG. 5 shows another embodiment of the invention. This example is
Basically, the structure is similar to the embodiment shown in Fig. 2, in which the cathode electrode also serves as a part of the wall of the vacuum chamber, and the number of rows of raw material gas discharge ports opened in the cathode electrode and the number of rows of raw material gas discharge ports that are housed in the vacuum chamber are determined. Since the pond parts have the same structure except for the number of cylindrical base bodies and the rotation mechanism of the cylindrical base bodies, similar parts will be designated by the same reference numerals and detailed description thereof will be omitted. Omitted.

The major difference between the embodiment shown in FIG. 5 and the embodiment shown in FIG. 2 is that the four cylindrical base bodies 2a, 2b2c, 2d
are arranged on a circumference sharing the central axis of the cathode electrode 1, and the rotation of the central axis is made to rotate around itself by a cylindrical base rotation mechanism 12 arranged at the central axis of the cathode electrode, and the cylindrical Since there are four substrates and the deposition area is wider, it is necessary to adjust the film thickness distribution over a wider range, so the raw material gas discharge ports 11 opened in the vacuum side inner wall of the cathode electrode l are arranged in eight rows. .

The basic operation of each part is the same in the embodiment shown in FIG.
, 2a rotate around their axis and enable uniform film formation.

As explained above, the plasma CVD apparatus according to the present invention reduces the number of raw material gas discharge ports opened in the cathode electrode, and by arranging them in series parallel to the rotation axis of the cylindrical base, the film is formed in the direction of the rotation axis. It has the effect of making it easier to adjust the thickness distribution@Furthermore, by drilling gas discharge ports with different hole diameters in the hexagonal socket screw attached to the gas discharge port, the amount of gas discharge can be adjusted along the rotation axis. This has the effect of making it possible to finely adjust the film thickness distribution. 1. By using the present invention, it becomes easy to adjust the thickness distribution of -C even when depositing a film on a large area substrate, where adjustment of the film thickness distribution is complicated using conventional equipment. This has the effect of improving the uniformity and reproducibility of the deposited film characteristics, and has the effect of making it possible to mass-produce electrophotographic photosensitive drums, which is one of the purposes for which this apparatus is used, at low cost and stably.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a typical example of a conventional cylindrical plasma CVD apparatus, and FIG. 2 is a diagram showing the present invention. Fig. 3 is a cross-sectional view of the cathode electrode, and Fig. 4 (G) (b) is a hexagon socket head screw installed in the gas discharge hole. Il of
1 and 5 are partially arrow-cut perspective views showing a second embodiment of the plasma CVD apparatus of the present invention. 01 is a cylindrical cathode electrode, 2 is a cylindrical base, and 3 is a wall of a vacuum/empty chamber. body,
4 is a donut-shaped insulating insulator, 5 is a high-frequency power supply, 6 is a raw material gas supply/ξin 0.7 is an exhaust system, 8 is a heater for heating the base body, 9 is a base rotation mechanism, 10 is ground, 11 is a raw material gas discharge hole , 12 is a motor for rotating the base, 13 is a hexagon socket screw with a gas discharge port, 14 is a gas discharge port, and 15 is a hexagon socket screw for blocking the gas discharge port.

Claims (4)

[Claims] (1) A vacuum chamber is equipped with a cylindrical electrode and a counter electrode arranged to rotate around the central axis of the vacuum chamber, and raw material gas is released from a number of holes provided in the electrode. , plasma CV in which a source gas is sprayed onto the substrate on the counter electrode to form a deposited film on the substrate;
In apparatus D, a large number of raw material gas discharge holes are opened in the wall surface of the cylindrical electrode in a row parallel to the central axis of the electrode, and the cylindrical electrode has a double wall structure, so that the inside of the electrode is A plasma CV characterized by forming a gas chamber in
D device. (2) A plurality of cylindrical substrates are placed in the vacuum chamber,
The plasma CVD apparatus according to claim 1, wherein the plasma CVD apparatus is arranged so that its central axis is parallel to the central axis of the vacuum chamber. (3) When adjusting the film thickness distribution of the film deposited on the surface of the cylindrical substrate by applying a hole-free process to the hole in which the source gas is sprayed, unnecessary holes can be plugged with screws. Plasma CVD according to claim (1)
Device. (4) The amount of gas released can be changed by providing a gas release port in the center of the screw that is attached to the screw hole for spraying the raw material gas, and installing a screw with a different diameter of the release port into the screw hole. A plasma CVD apparatus according to claim (2), wherein the film thickness distribution can be adjusted.