JPS637369A - Film forming device by chemical vapor growth method - Google Patents

Abstract

PURPOSE:To prevent the entry of the powder formed by a chemical reaction in a gaseous raw material introducing pipe of a chemical vapor growth method film forming device into a reaction chamber and to prevent the deterioration in the quality of the thin film formed on a substrate surface by providing a dust removing filter to said gas introducing pipe near to the inlet of the reaction chamber. CONSTITUTION:After the inside of the reaction chamber 1 is evacuated to a vacuum through a discharge port 2 by a vacuum device 3, a high-frequency voltage is impressed between a susceptor 8 mounted with a cylindrical substrate 9 and an electrode 5 from a power source 6 and the gaseous raw material is fed through a controller box 12 from a gas cylinder 13 to the gas pipe 11. The gaseous raw material is introduced from many holes 10 into the reaction chamber 1 where the gas is converted to plasma by high-frequency discharge and the thin film by the cracking of the gaseous raw material is formed on the surface of the cylindrical substrate 9 rotated by a driving device 7. Since the powder by the gas cracking is already formed in the gas introducing pipe 11, the filter 14 is provided to the part, at the inlet to the reaction chamber 1, of the gas introducing pipe 11 to filter off >=0.15mum powder. The deterioration in the quality by the formation of projecting parts to the formed thin film by the entry of the powder into the reaction chamber and the sticking thereof to the surface of the substrate 9 is thus prevented.

Description

Detailed Description of the Invention [Technical Field] This invention relates to a chemical vapor deposition method in which a thin film is deposited by subjecting a substrate to thermal decomposition or chemical reaction.
n Deposition = CV D ;hereinafter referred to as CV
The present invention relates to a chemical vapor deposition film forming apparatus for forming a thin film on a substrate surface using a method (referred to as D method).

<Summary of the Invention> In summary, the chemical vapor deposition film forming apparatus of the present invention is capable of reacting raw material gas within the gas introduction pipe by installing a dust removal filter at or near the gas introduction port of the gas introduction pipe. By preventing the powder produced by this process from flowing into the reaction chamber, it is intended to prevent defects from occurring in one film due to adhesion of the powder to the surface of the substrate.

<Prior art and its drawbacks> CVD is one of the methods for forming a film on the surface of a substrate.
There is a law. FIG. 4 is a schematic configuration diagram of a film forming apparatus using a plasma CVD method, which uses a progenitor frequency wave to turn raw material gas into plasma and cause a chemical reaction.

The cylindrical reaction chamber 2 is internally closed and has an exhaust port 2 at the lower end.
By connecting the vacuum device 3 to the vacuum device 3, the gas pressure can be controlled. Further, a lid 4 is provided at the upper end of the reaction chamber 1, and the interior can be opened by removing this lid H4.

The outer peripheral wall of the reaction chamber 1 constitutes an electrode 5 made of a conductor, and is connected to a high frequency power source 6. A support body 8 connected to an external drive device 7 is disposed approximately in the center of the reaction chamber 1 . A base body 9, which is half of the cylinder 1, is mounted on this support body 8. The drive device 7 rotates the support 8 and the substrate 9 within the reaction chamber 1.

A heater is embedded in this support 8 and heats the surface of the base 1. The support 8 has a surface made of a conductive material and is electrically grounded, thereby forming the other electrode to be paired with the electrode 5. Therefore, the voltage from the high frequency power source 6 is applied between the electrode 5 and the support 8. A large number of gas inlets 10 are provided around the drum support 8.
A plurality of gas introduction pipes 11 are provided.

This gas introduction pipe 11 is connected to the controller box 12°
Cylinder box 13 that stores various gas cylinders through
It is connected to the.

In order to form a thin film on the surface of the substrate 90 using such a plasma CVDyv and film device, first, the inside of the reaction chamber 1 is evacuated by the vacuum device 3, and then the mixture ratio and flow rate are adjusted to a predetermined mixing ratio and flow rate by the control box 12. Raw material gas is introduced into the reaction chamber 1 from the gas introduction pipe 13. Next, a high frequency voltage is applied between the electrode 5 and the support 8 by the high frequency power source 6 to turn the raw material gas into plasma, causing the raw material gas to undergo a chemical reaction on the surface of the base 9 to form a thin film on the surface of the base 9.

However, the raw material gas regulated by the control box 12 sometimes undergoes a chemical reaction within the gas introduction pipe 11 and turns into powder.

If such a powder flows into the reaction chamber 1 and adheres to the surface of the substrate 9, and a thin film is formed on the powder, that portion may become a defect.

For example, in the case of a photoreceptor used in a copier or the like in which a photoconductor layer made of amorphous silicon is formed on the surface of a cylindrical base 9, raw material gas adheres to the surface of the base 9, and an amorphous silicon film is formed on the surface of the base 9. If this occurs, the amorphous silicon film in that area will grow abnormally, forming a convex defect. When an image is formed using such a photoreceptor, white spots may be developed in areas corresponding to the defective areas. Particularly in the middle tones, this white spot phenomenon sometimes appears conspicuously.

<Object of the Invention> An object of the invention is to provide a chemical vapor deposition film forming apparatus that prevents powder generated by a chemical reaction within a gas introduction pipe from flowing into a reaction chamber.

<Structure and Effects of the Invention> The present invention provides a chemical vapor deposition film forming apparatus for forming a thin film on the surface of a substrate by reacting a raw material gas introduced into a reaction chamber from a gas introduction pipe on the surface of the substrate. The present invention is characterized in that a dust removal filter is attached to the introduction pipe for introducing gas into the reaction chamber or near its mouth.

According to the present invention configured as described above, even if the raw material gas reacts in the gas introduction pipe and forms powder, the dust removal filter installed at or near the gas introduction port to the reaction chamber Since it is removed, it does not flow into the reaction chamber. Therefore, it is possible to prevent the powder products of the raw material gas from adhering to the surface of the substrate in the reaction chamber, thereby preventing defects from occurring in the thin film formed on the surface of the substrate.

<Embodiment> FIG. 1 is a diagram showing a cross section of a gas inlet pipe of a CVD method film forming apparatus according to an embodiment of the present invention.

This gas introduction pipe is attached to the plasma CVD film forming apparatus shown in FIG. 4, and the same parts as in FIG. 4 are denoted by the same numbers and the explanation will be omitted.

A filter 14 is provided immediately before the plurality of gas introduction pipes 11 are drawn into the reaction chamber 1.

This filter 14 is capable of trapping most powder particles having a diameter of 0.12 μm or more. Monosilane (
An amorphous silicon film was formed on the surface of an aluminum base 9 using S i H4) as the main raw material gas. The surface of the photoconductor thus prepared had a diameter of φ10. The number of convex defect portions larger than um was observed using a microscope. Second
The figure shows the observation results. In addition, the surface of the photoconductor with a diameter of
The number of convex defect portions larger than μm was similarly observed. As is clear from this figure, it was possible to significantly reduce the number of defects in the photoreceptor produced by the plasma CVD apparatus provided with the filter 14 of the present invention. As a result, when an image was formed using the photoreceptor produced by the plasma CVD apparatus of the present invention, a good image quality without white spots could be obtained.

FIG. 3 (Al is an example in which a dust removal filter is provided immediately before the gas introduction port to the reaction chamber as another embodiment of the present invention. A filter 15 is provided along the gas introduction port 10 of the gas introduction pipe 11. This filter 15 has a diameter of φ0.
It is capable of capturing powder of 1 μm or more.

Using such a plasma CVD apparatus, a photoreceptor was prepared in the same manner as in the above-mentioned example, and the number of convex defect portions with a diameter of 30 μm or more on the surface was observed using a microscope. Figure 3 (Bl
is a diagram showing the results, and is comparison data with a convex defect portion on the surface of a photoreceptor created using a conventional plasma CVD apparatus. In this manner, by providing the filter, the convex defect portions on the surface of the photoreceptor (substrate) can be significantly reduced.

Further, according to the experiments conducted by the present inventors, a filter capable of using this filter was able to obtain better effects.

Furthermore, by providing these filters 14 and 15, the powder will not flow back into the gas introduction pipe 11 when leakage occurs in the reaction chamber 1 due to the reaction of the raw material gas formed in the reaction chamber. This has the advantage of preventing contamination.

[Brief explanation of the drawing]

Figure 1 shows a chemical vapor deposition method (CCV) which is an embodiment of this invention.
Method D) A cross-sectional view of the gas introduction pipe of the film forming apparatus. Figure 2 shows the number of defects on the photoreceptor surface created using the CVD film forming apparatus using this gas introduction pipe and the conventional apparatus. CAI is a cross-sectional view of the gas introduction pipe of a CVD film forming apparatus according to another embodiment, and FIG. FIG. 4 is a diagram comparing the surface defects of a photoconductor produced using a film-forming apparatus and a photoconductor produced using a conventional film-forming apparatus, and is a schematic diagram of a CVD film-forming apparatus. 10-Gas inlet, 11-Gas inlet pipe, 14.15-Filter. Figure 1 Figure 2 Figure 3 (B) Figure 3 (A)

Claims (1)

[Claims] (1) In a chemical vapor deposition film forming apparatus that forms a thin film on the surface of a substrate by causing a raw material gas introduced into the reaction chamber from a gas introduction pipe to react on the surface of the substrate, the gas introduction pipe enters the reaction chamber. A chemical vapor deposition film forming apparatus characterized in that a dust removal filter is installed at or near the gas inlet (2) The dust removal filter is a filter that captures dust of at least 0.15 μm or more. The chemical vapor deposition film forming apparatus according to item 1.