JPH0261071A - Plasma treating device and plasma treatment - Google Patents

Abstract

PURPOSE:To form and etch a film with high productivity by supplying a gaseous reactant into a space wherein a substrate to be treated is arranged, producing plasma by a glow discharge by a couple of electrodes, and impressing an AC bias voltage from a separate power source on the substrate when the film is formed and etched. CONSTITUTION:A film is formed and etched by plasma in a reaction chamber 7. In this case, a carrier gas 31 such as Ar, a gaseous reactant 32 such as methane and ethylene, an additional gas 33 such as NF3, and gaseous O2 34 for etching are supplied into the chamber 7 from a nozzle 25, and plural substrates 1'-1 to 1'-n are arranged. An AC voltage is impressed between the first and second electrodes 3 and 3' from a power source 15-1 to generate a glow discharge, hence the gaseous reactant is converted to plasma, and a hardcarbon based film is formed on the surface of the substrate 1 or etched by gaseous O2 plasma. In this case, a low-frequency second AC voltage is impressed on the substrate 1 from a separate power source 15-2 to impress an AC bias voltage, and the film is formed or etched with high productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a plasma CVD or plasma etching apparatus that supplies a large amount of power and a method for manufacturing the same. Furthermore, the present invention relates to a gas phase reaction or a gas phase cleaning or etching method for forming a film on a large amount of cylindrical substrates or other substrates at one time.

"Prior Art" Generally, in the plasma CVD method, a method of forming a film in a planar shape on a substrate having a flat surface is considered to be industrially effective. Furthermore, a method is also known in which a film is formed using a plasma CVD method while also producing a sputtering effect. Regarding carbon film coating, which is a typical example,
Patent application filed by the present inventor: Composite with carbon coating and method for producing the same J
(filed on September 17, 1981) 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 the upper surface of the flat surface using self-bias. Alternatively, active species are strongly excited using a microwave excitation method to form a hard carbon film on a substrate.

``Conventional Problems J'' However, in the conventional method of forming a film while producing such a sputtering effect, it is not only impossible to form a film on the upper surface of a cylindrical substrate, but also to form a film on an uneven substrate or a large amount at a time. Therefore, there has been a need for a method in which a large number of substrates are arranged in a large capacity space, a large amount of power is supplied, and a coating is formed on them at the same time. This is what was done.

Means to Solve the Problem "The present invention arranges a pair of electrodes spaced apart from each other. In order to perform plasma processing (plasma etching, plasma CvD, plasma cleaning, etc. are collectively referred to as plasma processing) by supplying a large electrode, a first alternating voltage is applied between the pair of electrodes.

To each of these electrodes, the high frequency voltages are applied from respective high frequency power supplies with different phases such as 180° or 0° relative to the ground controlled by a phase adjuster,
Alternating voltages that are symmetrical or in phase with each other can be applied. As a result, a substantially single alternating voltage is applied within the frame structure to induce a high-power high-frequency plasma.

Furthermore, the other end of each high-frequency power source is grounded, and another second alternating voltage is applied between this end and the substrate or substrate holder having the surface to be processed. By making this substrate holder (also simply referred to as a holder) or the substrate act as a third electrode and applying an alternating current bias on this substrate,
This is an attempt to perform plasma processing while also producing a sputtering effect.

The first alternating voltage is set to a frequency of 1 to 50 MHz, which is a frequency at which glow discharge tends to occur, and the second alternating voltage is set to a frequency of 1 to 50 MHz.
00KHz is applied as a frequency that makes it easy to add kinetic energy to the reactive gas. Furthermore, one end of this second alternating voltage and the other end of each matching coil for generating the first alternating voltage are both at ground level, and as a result, the second alternating voltage
A negative direct current self-bias is superimposed and applied to the output side of the alternating voltage. The first alternating voltage then accelerates the plasma-activated gas onto the substrate by self-biasing, and the unnecessary charged-up charge on the substrate is removed by the second alternating voltage. In this way, even if the surface to be formed has insulating properties, it is possible to perform plasma treatment on that surface.

In the following, plasma treatment, especially plasma C
I will focus on VD.

As an example of forming a thin film using this plasma CVD method, a hydrocarbon gas such as ethylene (CJn), methane (CH4), acetylene (C2112), a mixed gas of this and nitrogen fluoride, or a fluorocarbon gas, etc. By introducing carbon fluoride gas and decomposing it, a C-C bond similar to that of diamond with sp'' orbitals is created, and it has a specific resistance (specific resistance) of IX10' to IXIO''Ωcm and optical energy. The band width (called Eg) is 1.
A carbon film having properties similar to diamond that is transparent in the infrared or visible region with a voltage of OeV or more, preferably 1.5 to 5.5 eV was formed. In the present invention, the substrate is actively heated. Therefore, it is also possible to fabricate carbon or a film mainly composed of carbon on an organic photosensitive drum having an organic resin photoreceptor on an aluminum base material.

When forming a film using the method of the present invention, the film can be formed by simultaneously adding phosphorus or boron to the film using phosphine or diborane, either uniformly or with a gradient in the thickness direction. Presence or absence of carbon-based coating or additives in which a halogen element such as fluorine and nitrogen are added to carbide gas and nitrogen fluoride is simultaneously mixed in during plasma CVD to create a uniform concentration gradient in the thickness direction. It is also possible to create a multilayer composite membrane with controlled

The plasma processing apparatus of the present invention and the plasma processing method using the same will be described below according to the drawings.

"Example 1" FIG. 2 shows an outline of a plasma processing apparatus for carrying out the method of forming a thin film on a cylindrical substrate of the present invention.

In the drawing, a reaction vessel (7) of the plasma processing apparatus is separated by a loading/unloading preliminary chamber (7') and a gate valve (9). In the gas system (30), hydrogen or argon as a carrier gas is added to (31), and a hydrocarbon gas as a reactive gas, such as methane or ethylene, is added to (31).
From 2), nitrogen fluoride, which is an additive gas, from (33),
Oxygen, which is an etching gas in the reaction vessel, is supplied to the reaction system (50) from (34) through a valve (28) and a flow meter (29).
) through the nozzle (25). Then, when ethylene and fluoride are introduced, the diamond-like carbon film (also referred to as DLC) to which nitrogen and fluorine are added, including DLC to which additives are added, forms a diamond-like carbon film containing carbon or carbon as the main component. (referred to as a film) can be formed.

The reaction system (50) has a frame structure (2) (having a square or hexagonal frame structure when viewed from the electrode side) as shown in FIGS. A hood (8) is attached to the opening to cover the opening.

(8°). A pair of first and second electrodes (3) having the same shape are disposed in the hoods (8), (8'').

(3°) is made of aluminum metal mesh. The reactive gas is emitted downward from the nozzle (25). The third electrode is an electrostatic copying drum with aluminum as the base material and a photoreceptor on it.The photoreceptor is an insulating material in direct current terms, but a second alternating voltage is applied here, and in alternating current was made substantially conductive and a bias was applied. This base (
1) The upper surface to be formed (1゛) is connected to a pair of electrodes (3), (3”
) was maintained in the plasma generated by the Substrates (1-1), (1-2), ... (1n), that is, (
1) has surfaces to be formed (1'-1) and (1'-2)
...(1'-n), and an alternating voltage of 1 to 500 KHz to which a second alternating voltage and a negative DC bias are applied is applied. The reactive gas that has become plasma in the glow discharge due to the first high-frequency alternating voltage is uniformly dispersed in the reaction space (60), and this plasma is (2), (8),
(8"), and the plasma was not emitted into the external space (6) outside of this to prevent it from adhering to the inner wall of the reaction vessel. Furthermore, the plasma potential in the reaction space was made homogeneous.

Furthermore, in order to make the potential distribution in the plasma reaction space more equal, alternating voltages of two different frequencies can be applied to the power supply system (40). The first alternating voltage is 1~
It is a high frequency of 100MHz, for example 13.56MHz,
Two power supplies forming a pair (15-1), (15-2)
More matching transformer (16-1), (16-2
). The phase in this matching transformer is adjusted by a phase adjuster so that the signals can be supplied with a mutual deviation of 180° or 0°. Of course, if the base is asymmetrical, the optimum phase will deviate from these, but this can be controlled by a phase adjuster. The transformer has a symmetrical or in-phase output, and one end (4) and the other end (4') of the transformer are connected to a pair of first and second electrodes (3), (3'
) are connected to each other. In addition, the midpoint (5) on the output side of the transformer is held at the ground level, and the second 1 to 500
An alternating electric field (17) of KHz, for example 50 KHz, is applied. The output is the base (1-1'), (1-2''
), . . . (1-n''), ie, (1) or the third electrode of the holder (2) electrically connected thereto.

Thus, plasma (60) is generated in the reaction space.

The exhaust system (20) exhausts unnecessary gas through a pressure regulating valve (21), a turbo molecular pump (22), and a rotary pump (23).

゛These reactive gases are 0.00
1 to 1, Otorr, for example 0.05torr,
This frame structure (2) has a rectangular or hexagonal shape, for example, in the case of a rectangular shape, the width is 75 cm as shown in FIG. 3(A),
The depth was 75cm and the height was 50cm. Then, a cylindrical substrate having a surface to be formed is placed inside (1-1), (1-2).
. . (1-n) As shown in . . ., here, 16 pieces are arranged at equal intervals.

Dummy base materials (1-0) and (1-n+1) are also arranged inside the outer frame structure (2) to form a uniform electric field. In such a space, 0.5 to 5 KW (0.3 to 3 W per unit area) at a frequency of 13.56 MHz
/cm, for example 0.6W/cm2 per unit area
A first high frequency voltage of high energy) is applied. Furthermore, by applying an AC bias using a second alternating voltage, a voltage of -200 to -600 V (for example, the output is 5
00W) (7) A negative self-bias voltage was applied, and a film was formed while sputtering a reactive gas accelerated by this negative self-bias voltage on the substrate, and a dense film was formed.

Of course, the height of this quadrilateral (rectangular parallelepiped) frame structure can be adjusted from 20cm to 1m depending on design needs, and the sides can be adjusted to 30cm.
It may be from cm to 3 m. Further, the first alternating voltage may also be applied not between the upper and lower sides but between the front and rear as shown in the drawing from the top of the device.

The reactive gas was, for example, a mixed gas of ethylene and nitrogen fluoride. The ratio is NFi/CzHa = 1/4 to 4/
1, typically -171. By varying this ratio, transmittance and specific resistance can be controlled. The temperature of the substrate is typically maintained at room temperature. Thus, the specific resistance on the surface to be formed is lXl0'~1x1013Ωc
m, and is formed into a film in close contact with the mechanical fat film. A film having a transparent amorphous structure or a crystalline structure, or a film mainly composed of carbon, which is transparent to infrared or visible light, was formed to a thickness of 0.1 to 1 μm, for example, 0.5 μm (at the center). The deposition rate was 100-1000 people/min.

Thus, on the organic resin photoreceptor of the electrostatic copying drum, which is the base, a coating containing carbon as a main component, especially 3 hydrogen atoms in carbon, was applied.
It was possible to form carbon containing 0 atomic % or less, 0.3 to 3 atomic % of fluorine, and 0.3 to 10 atomic % of nitrogen.

It was also possible to form a film mainly composed of carbon having P, ■, or N type conductivity.

"Example 2" This example is an example of producing a film mainly composed of carbon on an electrostatic drum as shown in FIG. 1 using the apparatus used in Example 1.

FIG. 1(8) shows a cross-sectional view of a cylindrical electrostatic copying drum. An enlarged view of the main part is shown in FIG. 1(B).

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

In the present invention, in particular, this carbon or carbon-based coating prevents the toner from seeping out in the lateral direction, and
To prevent charge-up, its specific resistance is lXl0'~
in the range of 1×10 Ω CII+, particularly preferably lXl
The range was 09 to lXl0''ΩCl1l.

In the area to be copied, even if the organic photoreceptor (47) is locally deformed by pressing with a squeegee or copying, the protective film (44) will not crack or peel. Further, even after copying 100,000 sheets of A4 size paper, no scratches were generated on the surface due to rubbing of the copy paper.

"Example 3" In Example 1, when the local pressure on the drum was further strengthened, there was a tendency for the protective layer to peel off little by little from the ends of the cylindrical base. For this reason, although the cross-sectional views are shown in FIGS. 1(C) and 1(D), the area (
12) The thickness of the outer protective film was made relatively thick to promote prevention of wear and peeling.

FIG. 1(B) shows a case where the protective film at the end portions has the same thickness as that at the center portion, as shown in Example 1.

In FIG. 1(C), the protective film (45) is formed relatively thick at the end.

Furthermore, in FIG. 1(D), the thickness of the end portion (11) is
It shows a structure that is relatively thinner or removed compared to 2).

These are adjusted to be arranged near the pair of electrodes using the plasma CVD apparatus shown in FIG. 2, and when the pressure in this plasma reaction is 0.05 torr, the result shown in FIG. At 0111-0.1 torr, Figure 1 (
C) is obtained, and at 0.01 to 0.04 torr, FIG. 1(D) is obtained. During film formation, the ends of unnecessary parts may be partially covered with a cover if necessary.

The other methods for forming the protective layer are the same as in Example 1.

"Example 4" This example is a case where oxygen was introduced into the reaction space in Example 1. Carbon or a coating mainly composed of carbon as shown in Example 2 is formed on this frame structure, hood, etc. It was possible to perform plasma etching and removal by supplying high power according to the present invention.

After this, hydrogen is added to this reaction chamber, and the reaction vessel, frame structure,
Oxide adhering to the hood was removed by etching with hydrogen.

It goes without saying that the gas may be changed depending on the object to be etched. The rest was in accordance with Example 1.

"Example 5" In this example, argon was introduced into the reaction space. Argon plasma impinged on the substrate stored in this reaction vessel and caused sputtering, thereby cleaning the surface.

The rest was in accordance with Example 1.

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

DLC is shown as an example of a film formed by the method of the present invention. However, inorganic materials such as silicon carbide, silicon nitride, silicon oxide, and silicon, or other organic resin films may also be used. Furthermore, a magnetic material or a superconducting material may be used.

As is clear from the above description, the present invention is characterized by being able to supply high-power plasma to the reaction space, and furthermore, it is easy to generate plasma in the reaction space, and as seen in many other embodiments, the present invention has many applications. It is unknown.

By alternately repeating the plasma etching shown in Examples and the plasma CVD shown in Example 1, cleaning the inside of the reaction vessel did not take much time and the mass production effect was excellent.

[Brief explanation of the drawing]

FIG. 1 shows an example in which a cylindrical substrate of the present invention is coated with a carbon film. FIG. 2 shows an outline of a manufacturing apparatus for a plasma processing apparatus according to the present invention. Figures 3 (A) and (B) show the plasma C shown in Figure 2.
The arrangement method of the base in the VD device is shown.

Claims (1)

[Claims] 1. A plasma processing apparatus for forming a film or plasma etching by converting a reactive gas into plasma using a pair of electrodes spaced apart from each other, and having a power source for generating a pair of alternating voltages, each of which one end of the output of the matching transformer is connected to the pair of electrodes, the other end of the output of the transformer is grounded, and the pair of power supplies is provided with a phase adjuster for controlling the phase. A plasma processing device featuring: 2. In claim 1, a substrate having a surface to be formed or a surface to be etched is spaced apart from a pair of electrodes, and a voltage applied to the pair of electrodes is provided between a conductive portion of the substrate and ground. A plasma processing method characterized by comprising means for applying a second alternating voltage having a frequency lower than that of the second alternating voltage. 3. When forming a film or plasma etching by converting a reactive gas into plasma using a pair of electrodes spaced apart from each other, a power supply that generates a pair of alternating voltages with controlled phases is used to A plasma processing method, characterized in that one end of the output is connected to the pair of power sources through a matching transformer, and the other end of the output is grounded, thereby controlling the plasma state in the plasma space for processing.