JPS61288077A - Thin film forming device - Google Patents

Abstract

PURPOSE:To prevent the intrusion of the pulverous powder of the reaction product into a discharge system and to permit easy pressure regulation by installing heating means into a vessel except the space where the electrodes for impressing voltage provided to face each other and a substrate face each other. CONSTITUTION:The substrate 1 and the electrodes 4 facing the substrate are provided in the vessel 2 and the heating means 31, 36 are provided therein except the space where the electrodes 4 and the substrate 1 face each other. A reactive gas is then introduced into the vessel 2 and the voltage is impressed between the substrate 1 and the electrodes 4, by which the above-mentioned reactive gas is converted to plasma and is thus cracked and activated. Covers 32, 33, 34, 35 and the electrodes 4 are at the same time heated by the heaters 31, 36. The active seed of the resultant product of cracking is stuck in the form of a film-like resultant product 37 on the substrate. The generation of the pulverous powder is thus prevented and the clogging of the discharge system is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Summary) This is an improvement of a thin film forming apparatus used for manufacturing amorphous silicon used in electrophotographic photoreceptors, etc., in particular, using a reactive gas such as silane (SiH4) gas or disilane (5i2H6) gas. A thin film generating device that prevents deterioration of the exhaust characteristics of the device due to fine powder of silicon, which is a decomposition product, when decomposing amorphous silicon to form amorphous silicon.

[Industrial application field]

The present invention relates to a thin film forming apparatus, particularly an amorphous silicon thin film forming apparatus used for electrophotographic photoreceptors, and more particularly to a thin film forming apparatus that prevents deterioration of exhaust characteristics of the apparatus due to fine silicon powder generated by decomposition of a reaction gas. Regarding equipment.

A photoconductive layer formed around the recording drum is uniformly charged, and the photoconductive layer is irradiated with laser light based on printed information to selectively lower the charged potential of the photoconductive layer. to form an electrostatic latent image.

Thereafter, an electrophotographic apparatus such as a laser printer is well known in which a charged toner is applied to the latent image forming area and developed, and the developed printed image is transferred and recorded on recording paper.

Conventionally, selenium (Se) has been used as such a photoconductive layer.
Se-based materials have been used, but this Se is harmful;
Pollution problems occur when discarding after long-term use. In addition, the mechanical strength is low, and scratches occur on the surface of the photoconductive layer, causing many problems such as deterioration of printing quality when used for a long time.

Therefore, recently S
A recording drum has been developed in which an amorphous silicon photoreceptor layer, which is harmless to the human body and has high mechanical strength, is formed instead of e.

[Conventional technology]

FIG. 2 is a schematic diagram of a conventional WiM forming apparatus for forming such amorphous silicon.

As shown in the figure, in the conventional thin film forming apparatus, a cylindrical base 1 having a heater (not shown) inside is installed in an airtightly sealed container 2 and rotated by a motor 3. . A cylindrical electrode 4 with a hollow interior and a double structure is provided around the base 1, and a gas introduction tube 5 connected to the electrode 4 is filled with gas for forming an amorphous silicon photoreceptor layer. A disilane (Si2H6) gas cylinder 6 is connected.

Further, a large number of gas discharge lowers are provided on the surface of the electrode 40 facing the base 1, and a high frequency power source 8 is connected to one end of the gas introduction pipe 5 connected to the electrode 4.

Further, the exhaust port 9 of the container 2 is provided with a valve 10 as an exhaust system.
A strainer 11 for filtering the fine powder of the reaction product, a mechanical booster pump 12, and a rotary pump 13 are connected.

To explain the case of forming an amorphous silicon layer on the substrate 1 using such a device, first, the substrate 1 is placed in the container 2, and then the valve 10 is opened and the exhaust system, which is separately provided (not shown), is opened. diffusion pump,
Alternatively, use a rotary pump to pump 1O-6t inside the container 2.
Evacuate until the vacuum level reaches orr. Next, the base 1 is
After heating to 0 to 300°C, disilane gas is introduced into the container 2 from the disilane gas cylinder 6, and the inside of the container is heated to Q, 5 t.
A glow discharge is generated by applying a high frequency voltage between the substrate 1 and the electrode 4 using the high frequency power supply 8 while maintaining the pressure to about The introduced gas is turned into a plasma state, and the decomposition products of the gas are deposited on the substrate 1 to form an amorphous silicon layer.

[Problem that the invention seeks to solve]

By the way, as shown in FIG. 3, the temperature of the upper region 21 and bottom region 22 of the inner wall of this container 2 and the surface of the electrode 4 has not increased as much as the temperature of the base 1. Therefore, active species such as excited molecules, excited atoms, free radicals, and ions generated by the decomposition of disilane gas do not adhere to the surface of the heated substrate 1 as a film-like amorphous silicon, but rather are deposited on the inner wall where the temperature is low. Fine silicon powder 2j is deposited on the upper region 21, the bottom region 22, the surface of the electrode 4 facing the base 1, and both ends of the electrode 4. Then, this fine silicon powder 23 passes through the exhaust port 9 and enters the valve 10 shown in FIG. There is.

For this reason, the pressure inside the container 2 has been adjusted by manually opening the valve 10 or by using an automatic pressure regulator, but such devices are complicated to handle and may affect the quality of the film formed inside the container 2. There was a drawback that pressure adjustment that affected the temperature could not be carried out accurately.

Therefore, there is a problem that the characteristics of the amorphous silicon photoreceptor formed are not stable.

In addition, a mechanical booster pump 12 is further provided than the valve 10.
There is a problem in that the fine silicon powder 23 gets into the rotary pump 13 and reduces the pump's pumping ability.

[Means for solving problems]

The purpose of the thin film forming apparatus of the present invention is to provide an apparatus that prevents the decomposition products of the reaction gas described above from being introduced into the exhaust port 9 of the container 2. As shown in FIG. Covers 32, 33, 34, and 35 equipped with heating means 31 such as sheathed heaters are provided so as to cover areas where the temperature is relatively low and where active species are formed. A heating means 36 is also provided on the back side of the opposite side.

[Effect]

The thin film forming apparatus of the present invention utilizes the phenomenon that active species become film-like silicon on the heated substrate 1 and adhere to the substrate 1.

That is, the heater 3 is placed so as to face the upper region 21 and the bottom region 22 of the inner wall of the container 2, where the temperature inside the container 2 is difficult to rise.
In addition, a heater 36 is installed on the back side of the surface of the electrode 4 facing the base 1.
By heating the heaters 31 and 36, the active species of the reaction products of the reaction gas are deposited on the opposite surface of the cover 32, 33, 34, 35 and the base 1 of the electrode 4 into a thin film of silicon. It is attached as a solid substance. The activated species then pass through the exhaust port 9 of the container 2 and become finely powdered silicon, so that they are prevented from being introduced into the exhaust system such as exhaust pulp.

〔Example〕

FIG. 1 shows a sectional view of essential parts of the thin film forming apparatus of the present invention.

As shown in the figure, in the thin film forming apparatus of the present invention, a heater 31 is installed so as to cover an upper region 21 and a bottom region 22 where the temperature does not easily rise, where active species are formed on the inner wall of the container 2.
In addition to providing covers 33 and 32 equipped with heaters 31 and 32, covers 34 and 35 equipped with heaters 31 are also provided at both ends of the electrode 4 where the temperature does not easily rise, and furthermore, covers 34 and 35 equipped with heaters 31 are provided on the back area of the surface of the electrode 4 facing the base 1. A heater 36 is installed.

When the reactant gas is thus introduced into the apparatus and a voltage is applied between the electrode 4 and the substrate 1 to turn the introduced reactant gas into a plasma state, the heaters 31 and 36 are simultaneously heated to cover the cover 32. 33, 34, and 35, and also heats the electrode 4.

Then, the active species of the decomposition products of the reaction gas form a film-like product 37, which adheres to the facing surface of the cover 32, 33, 34, 35 and the base 1 of the electrode 4, and therefore The fine silicon powder, which is a product of the reaction gas generated, will no longer pass through the exhaust port 9 at the bottom of the container 2 and move toward the exhaust valve, and the exhaust capacity of the exhaust system will not be reduced. Pressure is kept at a constant value.

A film-like product 3 attached to the surface of this cover 32, 33, 34, 35 and the surface facing the base 1 of the electrode 4-
7 should be removed by etching in a later process.

Moreover, instead of this embodiment, as another embodiment, the cover 32
．． The work becomes easier if a metal foil such as aluminum foil is placed on the surface of 33, 34, 35, and the solid decomposition products adhering to this metal foil are disposed of together with the metal foil.

The thin film forming apparatus of the present invention uses an exhaust system to evacuate the inside of the container while forming a thin film by plasma CVD.
It can be applied to devices in which active species of reactive gases collide to generate fine powder in the low temperature region of the device.

〔Effect of the invention〕

As is clear from the above description, according to the thin film forming apparatus of the present invention, it is possible to prevent the reaction product fine powder from entering the exhaust system, and therefore it becomes easy to adjust the pressure of the apparatus, which has a large effect on the quality of the produced film. Furthermore, since the inside of the container is not contaminated with fine powder, cleaning of the device becomes easier and maintenance of the device becomes easier. Furthermore, since the exhaust system is not contaminated, there is no performance deterioration of the exhaust system, and maintenance of the system is facilitated.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main parts of the thin film forming apparatus of the present invention, Fig. 2 is a schematic diagram of a conventional thin film forming apparatus, and Fig. 3 is an explanatory diagram illustrating a malfunction in the conventional apparatus. be. In the figure, 1 is a base, 2 is a container, 4 is an electrode, 9 is an exhaust port, 21 is an upper region, 22 is a bottom region, 31.36 is a heater, 32.33. g, 34.35 is a cover, and 37 is a film-like product.

Claims (1)

[Claims] A substrate (1) and an electrode (4) facing the substrate (1) are provided in a container (2), and a reactive gas is introduced into the container (2) to form a substrate (1). and an electrode (4) to turn the reaction gas into a plasma state, decompose and activate the reaction gas, and deposit it on the substrate (1), wherein: at least the electrode (4) and the substrate (1)
A thin film forming apparatus characterized in that a heating means (31, 36) is installed except for the space facing the.