JPS5964769A - Plasma cvd apparatus - Google Patents

Abstract

PURPOSE:To easily form an amorphous thin film with good quality even on the surface of a relatively large substrate, in a plasma CVD apparatus, by a method wherein a plasma discharge field is divided into two sections by a common gas permeable electrode and stock gas is uniformly supplied from a plurality of small orifices provided to opposed electrodes. CONSTITUTION:A cylindrical net like common electrode 3 having gas permeability is arranged in a vacuum container 2 and a cylindrical second selectrode 5 and a first electrode 4 having a plurality of small orifices are arranged to the inside and the outside of said electrode 3. High frequency voltage is applied to the common electrode 3 from a power source 6 while DC voltages are applied to both electrodes 4, 5 from power sources 7, 8 and a first and a second plasma discharge fields 9, 10 are provided between the electrodes 3 and 4 and the electrodes 3 and 5. Stock gas such as monosilane is supplied from an inlet 12 to be injected from the small orifices of the jacket shaped first electrode 4 and passed through the plasma discharge fields 9, 10 two times before and behind the common electrode 3 to form a uniform amorphous silicon layer with good quality on the surface of the second electrode 5 as a substrate.

Description

[Detailed Description of the Invention] The present invention applies, for example, to an amorphous silicon film (hereinafter referred to as "λ-8i film") on the surface of an aluminum cylinder.
This invention relates to a plasma CVI) device used to produce photosensitive abrasive materials for laser line printers.

Conventionally, this type of plasma CVD equipment has i, A pressure space e
Continuously introducing one or several types of raw material gas,
This raw material gas is passed through a plasma discharge field formed in the reduced pressure space to undergo plasma decomposition, and the decomposed gas is guided to the film-forming surface of the heated substrate to form an amorphous film on the film-forming surface. There's something I did.

However, in conventional equipment, the raw material gas passes through a single plasma discharge field and then is guided sideways to the film-forming surface of the substrate. It was difficult to generate it in a short time.

FIG. 1 is a vertical cross-sectional view of a conventional device 7, in which a coil-shaped electrode C is arranged on the outside of the side surface made of a non-metallic abrasive material of a decompression JJ-container that forms a decompression space 3 inside. A plasma discharge field d is formed inside the vacuum vessel 1), and a cylindrical substrate e whose film-forming surface faces the plasma discharge field is placed inside the vacuum vessel 1). A heating plate f is attached to the back (inner surface). Then, from the upper end of the reduced pressure container 1) to the reduced pressure container bl'Ul.
Through the inlet nozzle g, the raw material gas h is introduced into the film-forming surface of the substrate e through the plasma discharge field d. However, in a device with such a configuration, the nozzle g
Regarding the shape, size, and arrangement of the
[Unless the investigation is carried out, the film is generally formed sequentially on the substrate C using the raw material gas introduced into the depressurized space, resulting in differences in the film thickness depending on the distance from the population. A drawback is that it is difficult to form a film with a uniform thickness.

In order to eliminate this drawback, attempts have been made to introduce a large amount of raw material gas, but if a large amount of gas is introduced, the raw material gas will be discharged unreacted.

Another drawback is that raw material gas, which is generally expensive, is consumed with low efficiency. Furthermore, in the conventional device shown in Fig. 1, the side surface of the vacuum vessel must be made of a non-metallic, low-permeability, airtight, high-purity material such as quartz glass, since the electrode C is disposed on the outside of the side surface. Therefore, as a production device, there are problems in terms of ensuring strength and production cost.

FIG. 2 is a vertical cross-sectional view of the main part of a conventional device in which the above-mentioned drawbacks have been specifically eliminated.

The difference from Figure 1 is that electrode C' is in a vacuum vessel 1)'
F/Originally installed, therefore a vacuum vessel 1)
The constituent material of ' does not need to be non-metallic and can have a strong structure. However, in this case, various combinations of the potential between the electrode (' and the substrate C') have been considered and implemented. , which shows the voltage application state.That is, the combinations shown in FIGS. 3(a), (b), and (C) are 1. Except for (a), In both cases, a high-frequency electric field is formed between the electrode C' and the substrate C', and a uniform discharge space and a uniform film thickness are to be obtained between the electrodes C' and the substrate C'. For example, an attempt is made to obtain a uniform film thickness by dispersing the discharge into small holes provided in various parts of the divided or integrated electrode C', but even with such a configuration, it is difficult to obtain a uniform discharge in each part. The distance between C' and 01 cannot be made too large in order to wait until the state is Jul, and therefore there is a limit to the increase in the thickness of the discharge field d'.

Therefore, it is difficult to ensure a sufficient 11LI distance MII of the raw material gas with respect to the plasma discharge electric field d', and gas that is insufficiently plasma decomposed is likely to be supplied to the substrate. As a result, as mentioned above, there are disadvantages in that expensive raw material gas is discharged unreacted and that it takes a long time to form a film.

As mentioned above, conventional apparatuses have drawbacks in either type, and cannot simultaneously meet the requirements of producing a high-quality amorphous thin film on a relatively large substrate in a short time. .

The present invention has been made in view of the above two circumstances, and by providing electrodes in a reduced pressure space to form a plurality of plasma discharge fields by glow discharge, and supplying raw material gas to these plasma discharge fields, the present invention is relatively effective. Plasma C enables the production of high-quality amorphous thin films on large-area substrates in a short time and economically due to the high utilization rate of raw material gas.
The purpose is to provide a VD device.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a longitudinal cross-sectional view of the plasma CV I) apparatus 17t according to the present invention, and FIG. 5 is a side view of the structure 11J.

This device is provided with a vacuum vessel 2 that forms a vacuum space 1 inside, and has a cylindrical common type with a mesh or phase 1 air permeability at an intermediate position within the vacuum vessel 2. The pole 3 is arranged with its axis vertical. , and a first cylindrical electrode 4 is connected to the common electrode 3 on the outside of the common electrode 3 in the reduced pressure vessel 2.
A second cylindrical electrode 5 is disposed coaxially with the common electrode 3 and inside the common electrode. Then, the common electrode 3 is connected to a high frequency power source 6, and the first electrode 4 and the second electrode 5 are respectively connected to a predetermined DC power source 7.8. Between? (A plasma discharge field 9 of Sl is formed and a second
A second plasma discharge field 10 is formed between the ↑a electrode and the common electrode 3. In this case, if the second electrode 5 is also the substrate, the substrate will serve as the electrode, but
If the substrate is a non-conductive material, cover the substrate with -F of 1.-5. Jl is a heating device intended for temporary heating and is disposed inside the second electrode 5.

Note that the first electrode 4 has a large number of small holes 4a over almost the entire surface.
A jacket 13 on the outside of the electrode 4 is connected to the gas pipe 12 through the source gas 16 gas pipe 12.
, and can then be dissipated into the plasma discharge fields 9 and 10 through the large number of small holes 4a drilled in the inner surface of the electrode 4. Note that a conduit 2 for introducing raw material gas 16 is connected to the upper end of the reduced pressure container 2,
An exhaust path 14 including a vacuum pump 5 is connected to the lower end or other suitable location.

Next, the operation of the plasma CVD apparatus according to the present invention will be explained.

Now, operate the vacuum pump 15 to bring the inside of the reduced pressure container 2 to 1 (
After the pressure is reduced to 3 torr or lower, the pressure inside and outside the ILOrr and the required gas flow rate are maintained by adjusting the fine adjustment valve such as a needle valve for supplying the raw material gas to the decompression vessel 2, and the heating device 11 is activated. Then, the second electrode 5 is heated to a predetermined temperature. In addition, by applying predetermined voltages to the electrodes 3, 4, and 5, the first button is pressed.
A plasma discharge field 9a, 10 is formed between the pole 4 and the common electrode 3 and between the second electrode 5 and the common electrode 3.

As above! ; After that, the vacuum vessel 2 is removed from the conduit 12.
When monosilane or other suitable raw material gas 16 is supplied into the inside, this raw material gas 16 flows into the first discharge field 9 through the small hole 4a of the first electrode 4, and a plasma component force/clamp occurs.
Thereafter, the raw material gas J6 passes through the common electrode 3 and enters the second plasma discharge field 10, where it is further subjected to plasma decomposition.

The gas thus decomposed is transferred to the heated second electrode 5.
A-8i film etc. are deposited on the surface of 5. The raw material waste that is no longer needed is then removed from the exhaust path 14.
It is ejected from the intimidation container through the

The plasma CVD apparatus of the present invention divides the plasma radiation field into a first and second radiation field by means of an air-permeable common electrode, and provides small holes for material gas diffusion over substantially the entire surface of the first electrode. Therefore, regardless of the size of the substrate, the source gas is extremely uniform and plasma is emitted. 1.
．． After the necessary residence time in the facility, the plasma-decomposed state is deposited onto a substrate.

In addition, in the case of this device, the distance between the electrodes (i.e., between the common electrode 3 and the first electrode 4, between the common electrode 3 and the second electrode 5, or both) is η''; Department establishment
Insulation distance Fill: (in the case of one-side grounded power supply) or twice that distance (in the case of a dual-output levitated electric whale) ) Discharge can be prevented.

In the above embodiments, each plasma discharge field was explained as being formed from a cylindrical electrode that was a continuous product.
The present invention is not limited to this, and as another embodiment, for example, it may be formed by an assembly of a plurality of divided unit electrodes.

It is also possible to install another electrode between the common electrode and the second electrode (1) and the second electrode (2) to control ions, etc. in the plasma discharge field. It may also be set on the opposite side.

[Brief explanation of the drawing]

Figures 1 and 2 are top views of the conventional mounting, and Figure 3 is a schematic diagram of the arrangement of the electrode C relative to the substrate shown in Figure 2, its shape, and the state of heavy application. FIG. 4 is a longitudinal cross-sectional view of the plasma CVD equipment f (, 7) according to the present invention, and FIG. 5 is a cross-sectional view of the same. , 4・
...First cylindrical ↑1: pole, 5... Second cylindrical electrode, ]2...4 tube, ]3... Jacket. Patent applicant Takaharu Onishi, patent attorney representing Shimadzu Corporation

Claims (1)

[Scope of Claims] A second cylindrical electrode disposed opposite to the common electrode and forming a second plasma discharge field between the common electrode and the common Tel 4'M; A plasma CVD apparatus characterized by comprising: (2) The plasma CVD apparatus according to claim 1, wherein the second cylindrical ftj pole is used as a substrate for film formation.