JP2561515B2 - Coating method - Google Patents

Description

TECHNICAL FIELD The present invention is a plasma vapor phase reaction method for forming a film on a substrate having a tubular shape, and performs film formation on a large amount of tubular substrates at one time. It relates to a gas phase reaction method.

As an example of such a thin film of the present invention, carbon or a coating containing carbon as a main component, which has translucency in the infrared or visible region, is formed on a cylindrical electrostatic copying drum, and a wear-preventing protective film thereof is formed. It is a spiral. In particular, this protective film is intended to obtain a reinforcing material for the surface of the cylindrical substrate and a protective material against mechanical stress.

“Prior Art” Generally, in the plasma CVD method, a method of forming a flat film on a substrate having a flat surface is industrially effective. Further, although it is a plasma CVD method, a method of forming a film while also having a sputtering effect is known.
Regarding the coating of a carbon film, which is a typical example thereof, a patent application filed by the present inventor "Composite having carbon coating and method for producing the same" (Japanese Patent Application No. 56-146936, September 1981).
17th application) is known. However, these are methods in which a substrate is disposed on one electrode (cathode side) of a parallel plate type, and a carbon film is formed on a flat upper surface using self bias. Alternatively, it is a method of strongly exciting active species by a microwave excitation method to form a hard carbon film on a substrate.

"Conventional Problems" However, in the conventional example in which the film is formed while also incorporating such a sputtering effect, not only the film cannot be formed on the upper surface of the cylindrical substrate, but also a substrate having irregularities or a large amount of the film on the substrate at one time is formed. I can't make it. Therefore, there has been a demand for a method of arranging a large amount of substrates in a large capacity space and forming a coating film on them at one time. The present invention has been made for such a purpose.

"Means for Solving the Problem" In the present invention, the reaction space has a rectangular or hexagonal frame structure, and a cylindrical substrate having a formation surface in the frame structure is an address corresponding to the vertex of a square or an equilateral triangle. A plurality of them are arranged at equal intervals. A pair of electrodes are arranged on one end side and the other end side of the opening of the frame structure so as to be separated from each other. The tubular substrate is arranged in the direction perpendicular to the electrode surface. First between a pair of electrodes
The alternating voltage of is applied. To each of these electrodes, a voltage whose high frequency voltage is 180 ° or 0 ° different from each other with respect to the ground is applied from each high frequency power source, and an alternating voltage of symmetrical or in-phase is applied. As a result, a total of substantially one alternating voltage is applied to the frame structure to induce high-frequency plasma. Further, the output side midpoint of each of the transformers is grounded, and another second alternating voltage is applied between this and the base body or the base body holder having the formation surface. This substrate holder (also simply referred to as a holder) or the substrate is made to act as a third electrode, and an AC bias is applied to this substrate to form a thin film with a sputtering effect.

Then, the first alternating voltage is set to a frequency of 1 to 50 MHz at which glow discharge is likely to occur, and the second alternating voltage is set to 1 to 500 K.
It is applied as a frequency that easily adds kinetic energy to the reactive gas of Hz. Further, one of the second alternating voltage and the other end of each matching coil for generating the first alternating voltage are both at the ground level, and as a result, the output value of the second alternating voltage is negative DC. Self-bias is superimposed and applied. Then, the first alternating voltage accelerates the plasma-activated gas onto the substrate by self-bias, and further unnecessarily charges up the charge on the substrate to the second AC voltage.
The voltage is removed. Thus, even if the surface to be formed has an insulating property, a film can be formed on the surface as well.

And as an example of the formation of this thin film, ethylene (C
₂ H ₄ ), methane (CH ₄ ), acetylene (C ₂ H ₂ ) hydrocarbon gas or mixed gas of this and nitrogen fluoride, or carbon fluoride gas such as carbon fluoride gas is introduced and decomposed. Creates a C-C bond similar to diamond with SP ³ orbital, and the specific resistance (specific resistance) is 1 × 10 ⁷ to 1 × 10 ¹³ Ωcm.
And a carbon film having an optical energy band width (referred to as Eg) of 1.0 eV or more, preferably 1.5 to 5.5 eV, which has characteristics similar to those of diamond translucent in the infrared or visible region. In the present invention, since the substrate is not heated positively, it is also possible to produce carbon or a coating film containing carbon as a main component on an organic photosensitive drum having an organic resin photosensitive member on an aluminum base material. .

Further, in the present invention, by arranging a large number of cylindrical substrates in the direction perpendicular to the pair of electrode surfaces, the ends thereof can be arranged in the vicinity of the dark cathode region and the dark anode region. Then, the film thickness to be formed can be increased in the vicinity of this end portion. As a result, a film is formed in the positive column region, and
It became possible to form a uniform film having a thickness of ˜1 μm. At the same time as this film formation, it is possible to form a film having a relatively large thickness at the end.

At the time of film formation by the method of the present invention, phosphorus or boron can be added at the same time using foshin or diborane while providing a uniform or gradient in the thickness direction. Presence or absence of carbon-based coatings or additives in which a halogen element such as fluorine and nitrogen are added to the carbide gas during plasma CVD and nitrogen fluoride is simultaneously mixed to provide a uniform concentration gradient in the thickness direction. It is also possible to make a multi-layer composite film in which the temperature is controlled.

 The manufacturing method of the present invention will be described below with reference to the drawings.

[Example 1] Fig. 2 shows an outline of a plasma CVD apparatus for carrying out a method for forming a thin film on a cylindrical substrate of the present invention.

In the drawing, the reaction vessel (7) of the plasma CVD apparatus is a loading / unloading preliminary chamber (7 ') and a gate valve (9).
It is divided by. In the gas system (30), hydrogen or argon, which is a carrier gas, is used (31), and hydrocarbon gas, which is a reactive gas, such as methane and ethylene (32).
From the additive gas nitrogen fluoride (33), the reaction vessel etching gas oxygen (34) to the valve (28) and flow meter (29) through the reaction system (50). It is introduced from the nozzle (25). Then, when ethylene and nitrogen fluoride are introduced, the diamond-like carbon film to which nitrogen and fluorine are added (also referred to as DLC, the present invention includes DLC with an additive added, and carbon or carbon is a main component). Called a film)
Can be formed into a film.

As shown in FIGS. 3 (A) and 3 (B), the reaction system (50) has a frame structure (2) (having a rectangular or hexagonal frame structure when viewed from the electrode side), and the upper and lower parts thereof. The opening of the hood (8), so as to cover this opening,
It has (8 '). The pair of first and second electrodes (3) and (3 ') having the same shape and arranged on the hoods (8) and (8') are made of aluminum metal mesh. The reactive gas is discharged downward from the nozzle (25). The third electrode is an electrostatic copying drum having aluminum as a base material and a photoconductor thereon, and the photoconductor is an insulating material in terms of direct current. Was made substantially conductive and a bias was applied. The surface (1 ') to be formed on the substrate (1) is connected to a pair of electrodes (3),
It was placed while being held in the plasma generated in (3 '). On the bases (1-1), (1-2), ... (1-n), that is, (1), the surfaces to be formed (1'-1), (1'-2) ...
An alternating voltage of 1 to 500 KHz having (1'-n), to which a second alternating voltage and a negative DC bias is applied, is applied. The reactive gas turned into a plasma of glow discharge by the first alternating voltage of the high frequency is uniformly dispersed in the reaction space (60), and this plasma is surrounded by (2), (8) and (8 '), The outer space (6) on the outside was not discharged in a plasma state so as not to adhere to the inner wall of the reaction vessel. The plasma potential in the reaction space was made uniform.

Further, in order to make the potential distribution in the plasma reaction space more uniform, alternating voltage of two kinds of frequencies can be applied to the power supply system (40). The first alternating voltage is 1-
A high frequency of 100 MHz, for example, 13.56 MHz, reaches the matching transformers (16-1) and (16-2) from a pair of two power sources (15-1) and (15-2). The phase of this matching transformer is adjusted by the phase adjuster (26),
It can be supplied at 0 ° or 0 ° offset. The output of the transformer is symmetrical or in-phase, and one end (4) and the other end (4 ') of the transformer are connected to the pair of first and second electrodes (3) and (3'), respectively. Further, the output side midpoint (5) of the transformer is held at the ground level and the second alternating electric field (17) of 1 to 500 KHz, for example 50 KHz is applied. The output is the substrate (1-1 '), (1-
2 '), ... (1-n'), that is, (1) or the third electrode of the holder (2) electrically connected to them.

Thus, plasma (60) is generated in the reaction space. The exhaust system (20) exhausts unnecessary gas through the pressure control valve (21), the turbo molecular pump (22), and the rotary pump (23).

These reactive gases are 0.001-1.0 in the reaction space (60).
The frame structure (2) has a quadrangle or a hexagon. For example, in the case of a quadrangle, the width is 75 cm, the depth is 75 cm, and the length is 50 cm, as shown in FIG. 3 (A).
Then, a cylindrical substrate having a surface to be formed therein ((1-
As shown in 1), (1-2) ... (1-n) ..., 16 are arranged at equal intervals here. Dummy base materials (1-0) and (1-n + 1) for forming an equal electric field are also arranged inside the outer frame structure (2). In such a space, 0.5 to ⁵ KW (0.3 to 3 W / cm ² per unit area) at a frequency of 13.56 MHz, for example, 1 KW (0.6 W / c per unit area)
The first high frequency voltage of high energy (m ² ) is applied. Furthermore, by applying an AC bias with a second alternating voltage, a negative self-bias voltage of -200 to -600V (for example, its output is 500W) is applied on the surface to be formed, and acceleration is performed by this negative self-bias voltage. It was possible to form a dense film while sputtering the generated reactive gas on the substrate.

Of course, the height of this quadrangular (rectangular parallelepiped) frame structure may be 20 cm to 1 m, and one side may be 30 cm to 3 m depending on the design requirements. The first alternating voltage may also be applied between the front and back, as shown in the drawing from above the device, instead of between the top and bottom.

The reactive gas was, for example, a mixed gas of ethylene and nitrogen fluoride. The ratio is NF ₃ / C ₂ H ₄ = 1/4 to 4/1, and is typically 1/1. By changing this ratio, the transmittance and the specific resistance can be controlled. The temperature of the substrate is typically kept at room temperature. Thus on a formation surface has a resistivity ^{1 × 10 7 ~1 × 10 13} Ωcm, is deposited in close contact to the organic resin film. 0.1 to 1 μm, for example 0.5 μm, of carbon or a coating containing carbon as a main component, which has a transparent amorphous structure or a crystalline structure for infrared or visible light
(Central part). The deposition rate was 100-1000Å / min.

Thus, a film containing carbon as a main component, particularly hydrogen in carbon, is formed on the photoreceptor of the organic resin of the electrostatic copying drum, which is the substrate.
It was possible to form carbon containing not more than 30 atomic% and 0.3 to 3 atomic% fluorine and 0.3 to 10 atomic% nitrogen. It was also possible to form a film containing carbon having a P, I or N conductivity type as a main component.

Example 2 This example is an example of producing a film containing carbon as a main component on the electrostatic drum as shown in FIG. 1 by the apparatus used in Example 1.

In FIG. 1 (A), a sectional view of a cylindrical electrostatic copying drum is shown. An enlarged view of the main part is shown in FIG.

In FIG. 1 (A), the electrostatic copying drum is made of an aluminum base material (11) and has a convex portion (42) at one end for providing a core for rotation and a screw thread (43) at the other end. ) Has. This fixes the threaded portion of the drum to the electrostatic copier itself, and the drum is rotated with each copy. An organic resin photoconductor (47) is provided on the conductive base material (41). This photoreceptor generally has a multilayer film of a photosensitive layer and a carrier conductive layer. Substrate (1) having the formation surface (1 ')
An abrasion-resistant protective film (44) containing carbon or carbon as a main component was provided thereon to a thickness of 0.1 to 3 μm.

In the present invention, the carbon or the coating containing carbon as a main component prevents the toner from seeping out in the lateral direction and also prevents the charge-up, so that the specific resistance thereof is 1 × 10 ^7.
To 1 × 10 ¹⁴ Ωcm, particularly preferably 1 × 10 ⁹ to 1 × 1
The range was 0 ¹¹ Ωcm. In the portion to be copied, even if the organic photoconductor (47) is locally deformed by pressing with a squeegee or copy, the protective film (44) is not cracked or peeled. Also, even if 100,000 sheets of A4 size paper were copied, no scratches were generated on the surface due to rubbing of the copy paper.

FIG. 4 shows an example thereof. When a protective film is formed and an initial copy is made, an example of the copy is shown in (A), and the result after 100,000 copies thereof is shown in (B). There was almost no difference between these. Conventionally known organic photosensitive drums have been able to copy only 20,000 sheets until now, but it has been found that it is possible to increase the number to 5 times or more at a time.

[Example 3] In Example 2, when the local pressure is further increased on this drum, the protective layer tends to peel off from the end of the cylindrical substrate little by little. For this reason, the cross-sectional views are shown in FIGS. 1C and 1D, but the area (12) where the copying is performed at both ends (11).
The protective film on the outer side of was relatively thickened to promote wear prevention and peeling prevention.

In FIG. 1 (B), a protective film is formed only on the upper surface at the end,
In addition, it is formed relatively thick. Figure 1 (C)
Shows the case where the protective film at the end extends to the side surface (13).

Further, in FIG. 1 (D), the thick end region is shown in FIG. 1 (C).
This is the case when it is provided slightly inside.

These are adjusted so that they are arranged near the pair of electrodes by using the plasma CVD apparatus of FIG. 2, and at the time of film formation, a cover may be partially covered on the end of the unnecessary portion, if necessary. Good.

 The method for forming the other protective layers is the same as in Example 1.

Example 4 In this example, the shape of FIG. 3 (B) was a frame structure, and a cylindrical substrate was provided. The side of the hexagon is 30 cm. It is effective when the reaction container (Fig. 2 (7)) has a cylindrical shape.

 The other plasma CVD methods and the like are the same as in the first embodiment.

With such an arrangement, the manufacturing cost of the reaction container can be reduced.

"Effect" The method of the present invention enables industrial mass production by setting the substrate side to have a voltage relationship that should have the sputtering effect on the cathode side and making the reaction space extremely large.

DLC is shown as an example of the film formed in the method of the present invention. However, it may be an inorganic material such as silicon carbide, silicon nitride, silicon oxide or silicon, or another organic resin film. Further, it may be a magnetic material or a superconducting material.

As is clear from the above description, the present invention is provided by coating an organic resin or a multilayer film thereof. This complex is of immeasurable application, as can be seen in many of the other examples, in particular the carbon
It is characterized in that it can be formed at a low temperature of ℃ or less and its hardness and adhesion to the substrate are extremely excellent.

According to the method of the present invention, since the film thickness is made uniform in the region where the substrate is subjected to electrostatic copying, it is not necessary to form a film while rotating each substrate, and there is no gear or the like necessary for the rotating work. It is possible to prevent the occurrence of flakes and form a protective film with few pinholes.

[Brief description of drawings]

FIG. 1 shows an example in which a carbon film is coated on the cylindrical substrate of the present invention. FIG. 2 shows an outline of the plasma CVD apparatus manufacturing apparatus of the present invention. 3 (A) and 3 (B) show the arrangement method of the substrates in the plasma CVD apparatus shown in FIG. FIG. 4 shows an example of electrostatic copying using an organic photosensitive drum produced by the method of the present invention.

Claims (4)

(57) [Claims] 1. When a reactive gas is made into plasma by a pair of parallel plate electrodes which are separated from each other to form a film, a plurality of cylindrical substrates for film formation are square or equilateral triangles at equal intervals when viewed from the electrode side. A method for producing a coating film, characterized in that it is arranged at the apex so that the axis is perpendicular to the electrode surface. 2. The cylindrical substrate according to claim 1, comprising an electrostatic copying drum having a photoconductor on a base material having a conductor surface, and forming a protective coating on the substrate. A method for producing a coating film, comprising: 3. A tubular substrate for forming a film when plasma is formed on a reactive substrate by a pair of parallel plate electrodes spaced apart from each other, and both ends of the cylindrical substrate on which the film is formed are near the dark cathode region and the dark anode region, respectively. A method for producing a coating film, characterized in that it is disposed and the central portion of the cylindrical space is disposed in the positive column region. 4. A method for producing a coating film according to claim 3, wherein a protective film is formed on the cylindrical substrate for an electrostatic drum so that both end portions thereof are relatively thicker than the central portion.