JP2003003260A - Hard carbon film manufacturing apparatus and method - Google Patents

Abstract

(57) Abstract: A uniform hard carbon film is quickly formed on a sliding component such as a bearing used in a magnetic disk recording device or an optical disk recording device. SOLUTION: In configuring a hard carbon film manufacturing apparatus for forming a hard carbon film by a plasma CVD method, an exhaust device is provided.
A support electrode 8 for supporting a conductive substrate 6 on which a film is to be formed is installed in a vacuum chamber 1 connected to a vacuum source 10.
And a power supply 4 for applying a voltage between the vacuum chamber 1 and the support electrode 8, and the vacuum chamber 1 is connected to the outer peripheral surface of the substrate 6 on which the film is to be formed. 6a, end face 6
has an inner surface shape similar to b, that is, an inner peripheral surface 1c and a top surface 1d,
It is configured such that an equal gap is formed between the film-forming surface. Thereby, a hard carbon film can be simultaneously formed on the outer peripheral surface 6a and the end surface 6b of the base material 6, and the time required for a predetermined degree of vacuum can be reduced. Further, a uniform hard carbon film can be formed with the gas density, the plasma density, and the like between the vacuum chamber 1 and the surface on which the substrate 6 is formed being constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard carbon film manufacturing apparatus and method for forming a hard carbon film on the surface of a conductive substrate, and more particularly to a magnetic disk recording apparatus,
The present invention relates to a hard carbon film manufacturing apparatus and method for forming a carbon hard film for improving wear resistance of sliding parts such as bearings of a spindle motor used in an optical disk recording device.

[0002]

2. Description of the Related Art In recent years, a hard carbon film has been formed as a protective film on the surface of various base materials such as metal, glass, ceramics, plastics, etc. to improve the abrasion resistance and mechanical strength of the base material. It is being appreciated.

Hard carbon film (DLC: Diamond Like Carbo)
n, i-carbon film) has a four-coordinate bond (SP3 bond) of carbon, similar to natural diamond, while it partially contains SP2 bond and hydrogen bond. It exhibits an amorphous structure that does not have a fixed crystal structure in distance order. However, this hard carbon film is not only extremely hard and wear-resistant, but also has excellent self-lubricating properties and very low surface roughness based on the same bond as the above-mentioned diamond, and therefore has a very low friction coefficient. , Has the characteristics. Furthermore, it is physically stable and has high chemical durability. Therefore, it is suitable for coating the parts that require hardness and abrasion resistance and the parts that require low friction in mechanical parts, especially in magnetic disk recording devices and optical disk recording devices. It is expected to be applied as a protective film used on the surface and bearing sliding parts of spindle motors.

To form a hard carbon film, an ion plating method, a sputtering method using graphite as a target, or a plasma CVD method using a carbon-based gas (Ch
emical Vapor Deposition) etc. are used. However, when depositing a film on the surface of a base material that becomes a mechanical component or bearing component with a complicated shape, the ion plating method or the sputtering method uniformly deposits vapor-deposited particles or sputtered ions on each part of the film-forming target. It is extremely difficult to irradiate the film with the film, and the film thickness and film quality are difficult to be uniform in each part under the present circumstances. Further, the sputtering method has a low film forming rate of about several tens nm / min, and is not suitable from the viewpoint of cost for mass production of inexpensive mechanical parts and bearing parts.
On the other hand, the plasma CVD method requires a relatively high voltage of several kV for glow discharge to generate plasma, but can form a large-area film by using an inexpensive gas as a film material. It is advantageously used for forming industrial thin films including films.

An apparatus for producing a hard carbon film by a plasma CVD method is disclosed in, for example, Japanese Patent Laid-Open No. 11-12.
It is described in Japanese Patent No. 5243. As shown in FIG. 6, this apparatus for manufacturing a hard carbon film was connected to a work holder 2 and a positive electrode, which were connected to a ground potential, inside a vacuum chamber 1 having an air supply port 1a and an exhaust port 1b. The plate-shaped electrode 3 is arranged, and plasma is generated by applying a voltage from the power supply 4.

When a hard carbon film is formed on the surface of a cylindrical base material that serves as a rotation axis with such an apparatus, as shown in FIG. 7 (a), a base 5 having a mask 5 on the outer peripheral surface 6a is used. The material 6 is placed on the work holder 2 so that its end surface 6b faces the electrode 3. Then, the inside of the vacuum chamber 1 is evacuated to a predetermined pressure or less, and then a source gas G such as a hydrocarbon gas is introduced into the vacuum chamber 1 so as to have a predetermined pressure, and a positive potential is applied to the electrode 3. By applying, the source gas G is decomposed into plasma to generate chemically active radicals and ions, and a thin film is formed on the end surface 6b of the base material 6. Further, as shown in FIG. 7 (b), the base material 6 having the mask 5 on the end surface 6b is placed on the work holder 2 so that the outer peripheral surface 6a faces the electrode 3 and is rotated about the axis. By generating plasma in the vacuum chamber 1 in the same manner as above, a thin film is uniformly formed on the outer peripheral surface 6a of the base material 6.

[0007]

However, in the conventional hard carbon film manufacturing apparatus, a substrate having a complicated shape having a plurality of film-forming surfaces with different directions, such as the above-mentioned columnar substrate, is used. Since it is necessary to form a film in a separate process for each surface, there is a problem in terms of labor and time of work, film forming cost, and the like.

Further, when a plurality of base materials are installed in a vacuum chamber to form a film, the gas density and the plasma density are different depending on the installation position, so that the film thickness, hardness, adhesion and film quality are different. Therefore, it is difficult to form a uniform hard carbon film on all substrates. Furthermore, since the exhaust volume of a vacuum chamber that supports multiple substrates is large, it takes time to reach a predetermined degree of vacuum, which increases the cost of film formation and is a low cost mass production conventional concept. It is not realistic to apply it to the rotating shaft for motors.

Therefore, even for a substrate having a complicated shape,
Further, the development of a hard carbon film production apparatus capable of rapidly producing a uniform hard carbon film for a plurality of substrates has been an issue.

[0010]

In order to solve the above-mentioned problems, the present invention has an inner surface having a similar shape to the film-forming target surface of the base material and forming an equal gap between the film-forming target surface and the film-forming target surface. By using a vacuum chamber, the exhaust volume is minimized to shorten the time to a predetermined degree of vacuum, and the gas density and plasma density between the vacuum chamber and the film formation target surface of the substrate are constant, This is intended to form a uniform hard carbon film.

That is, according to the present invention of claim 1, a supporting electrode for supporting a substrate to be film-formed is installed in a vacuum chamber connected to an exhaust means, and a gas supply for supplying a film material gas into the chamber. Means and a power source for applying a voltage between the vacuum chamber and the supporting electrode are connected to form a hard carbon film on the base material having conductivity by a plasma CVD method. In the apparatus, the vacuum chamber has an inner surface shape similar to the film formation surface of the substrate, and is configured to form an equal gap at each site between the vacuum tank and the film formation surface. To do.

Thus, even if the surface of the substrate on which the film is to be formed is a plurality of surfaces such as the end surface and the outer peripheral surface of the columnar body, or even a surface having irregularities, the surface to be formed is contacted. A uniform hard carbon film can be formed at the same time with a constant gas density, plasma density and the like. Further, at this time, since the individual base materials are housed in the individual vacuum chambers, the evacuation processing time up to a predetermined degree of vacuum is extremely short, and high mass productivity can be realized. Therefore, it is possible to provide the rotating shaft, the plate-shaped substrate, and the like that form the slide bearing at low cost.

Membrane material gas includes methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane and other saturated aliphatic hydrocarbons, ethylene, acetylene, propylene and other unsaturated aliphatic hydrocarbons, A carbon-containing gas such as aromatic hydrocarbons such as benzene, toluene and naphthalene and carbon oxides such as carbon monoxide can be used. At the same time as the carbon-containing gas, hydrogen, oxygen,
A simple substance gas such as nitrogen or argon, or a mixed gas thereof may be supplied. By introducing these gases, the film characteristics (hardness, smoothness, friction coefficient, adhesiveness) of the hard carbon film can be changed.

According to a second aspect of the present invention, in the hard carbon film production apparatus according to the first aspect, the gap between the inner surface of the vacuum chamber and the film-forming surface of the substrate is 2 to 20 mm. . It is desirable to make the gap as narrow as possible under the condition that plasma is generated in order to reduce the exhaust volume, and the gap range as described above is preferable.

According to a third aspect of the present invention, in the hard carbon film production apparatus according to the first aspect, a plurality of gases connected to a gas supply means are provided on the inner surface of the vacuum chamber facing the film formation surface of the substrate. It is characterized in that the introduction port is opened. As a result, the gas density and plasma density between the film formation surface of the base material and the inner surface of the vacuum chamber become more constant at each site, and uniform film formation is possible. It is desirable to provide the gas inlets at regular intervals.

According to a fourth aspect of the present invention, in the hard carbon film manufacturing apparatus according to the first aspect, an insulating member for covering the non-deposition target surface of the base material is arranged. This allows
It is possible to prevent film formation on the non-film-formation target surface.

According to a fifth aspect of the present invention, in the hard carbon film manufacturing apparatus according to the first aspect, a plurality of vacuum chambers are connected in parallel. As a result, the film forming conditions of the respective vacuum tanks can be made uniform, and the film can be uniformly formed on the individual substrates installed in the respective vacuum tanks.

According to a sixth aspect of the present invention, in forming a carbon hard film on a conductive base material by a plasma CVD method, a vacuum chamber having an inner surface shape similar to the surface of the base material on which the film is to be formed is formed. , The base material is supported by a supporting electrode so as to form an equal gap between the inner surface and the inner surface, and a film material gas is supplied at a predetermined pressure, while the substrate material gas is supplied between the vacuum chamber and the supporting electrode. A carbon hard film is formed on the surface of the base material by applying a voltage to generate plasma. Thereby, it is possible to simultaneously and quickly form uniform hard carbon films on a plurality of film formation surfaces of the base material.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. (Embodiment 1) FIG. 1 shows the configuration of a hard carbon film manufacturing apparatus in Embodiment 1 of the present invention. In this hard carbon film manufacturing apparatus, members having the same functions as those of the conventional hard carbon film manufacturing apparatus described above with reference to FIG. 6 are designated by the same reference numerals as those in FIG.

The vacuum chamber 1 has a main body 7 for accommodating a conductive base material 6 to be film-formed, and a detachable lid 9 having a support electrode 8 for supporting the base material 6. And lid 9
Around the support electrode 8 in, the air supply port 1a for supplying the film material gas into the tank and the exhaust port 1b for reducing the pressure inside the tank by vacuum are formed. An insulating member 8a is arranged around the supporting electrode 8 facing the base material 6.

The main body 7 of the vacuum chamber 1 is connected to the ground potential, and the supporting electrode 8 is connected to the high frequency power source 4. However, a DC pulse power source may be used in place of the high frequency power source 4, and a DC power source is used when forming a hard carbon film having low insulation (a hard carbon film having many dangling bonds). Negative voltage is applied to the supporting electrode 8 by the vacuum chamber 1
A ground potential and a positive voltage may be applied to the main body 7.

The exhaust port 1b of the lid 9 communicates with the exhaust device 10, and the air supply port 1a is connected to a gas supply source 11 having a gas flow rate adjusting function. The exhaust device 10 includes a rotary pump and a high vacuum pump selected from a turbo molecular pump, an oil diffusion pump, a cryopump, an ion pump, and the like.

More specifically, the vacuum chamber 1 is formed corresponding to a cylindrical conductive substrate 6 having an end surface 6b and an outer peripheral surface 6a as a film formation surface. It has a bottomed cylindrical inner surface shape similar to the surface, and is configured to have a size capable of forming an equal gap with the film formation surface. In order to make the exhaust volume as small as possible, this gap allows the plasma to be generated, and the gap between the inner peripheral surface 1c of the vacuum chamber 1 and the outer peripheral surface 6a of the substrate 6 and the top surface 1d of the vacuum chamber 1 are formed. End face 6 of substrate 6
It is preferably 2 to 20 so that the distance to a is as narrow as possible.
The space is designed to be about mm, and an airtight discharge space is formed between the base material 6 and the base material 6.

A method for manufacturing a hard carbon film in the above-described hard carbon film manufacturing apparatus will be described. The base material 6 is installed inside the vacuum chamber 1 by attaching the lid 9 supporting the base material 6 to the support electrode 8 to the vacuum chamber 1, and the inside of the chamber is set to about 10 ^-2 to 10 ^-5 torr by the exhaust device 10. Evacuate to the following vacuum level. Next, the film material gas G is introduced into the tank from the gas supply source 11,
Confirm that the gas pressure and gas flow rate in the tank have stabilized to the specified values. The gas pressure is, for example, about 10 ^-1 to 10 ^-3 torr or less. After that, a high frequency voltage of 100 to 1000 W is applied from the power source 4 between the support electrode 8 and the main body 7 of the vacuum chamber 1.

By doing so, plasma P is generated between the end surface 6b and outer peripheral surface 6a of the base material 6 supported by the supporting electrode 8 and the top surface 1d and inner peripheral surface 1c of the vacuum chamber 1, A hard carbon film is formed on the end surface 6b and the outer peripheral surface 6a of the base material 6.

At this time, since the substrate 6 is installed inside the vacuum chamber 1 having an inner surface shape similar to that of the film-forming surface, the evacuation processing time up to a predetermined degree of vacuum is extremely shortened. Since the gas density, the plasma density, and the like between the vacuum chamber 1 and the film formation surface of the base material 6 become uniform at each site, the base material 6
A hard carbon film is formed on the end surface 6b and the outer peripheral surface 6a of the same at a high speed with a uniform hardness, composition, structure, adhesion and the like over the entire surface. (Embodiment 2) FIG. 2 shows the configuration of a hard carbon film production apparatus according to Embodiment 2 of the present invention.

This hard carbon film manufacturing apparatus is different from the apparatus of the first embodiment described above in that the main body 7 of the vacuum chamber 1 is provided with a hollow portion 12 having a shape substantially similar to the outer shape of the main body 7. A plurality of gas inlets 12a for introducing gas into the hollow portion 12 are formed so as to open at the end face of the main body, and a gas supply port 12b for supplying gas from the hollow portion 12 into the main body is formed as a base. The point is that a plurality of materials 6 are formed at regular intervals so as to open on the surface facing the film formation surface, that is, the top surface 1d and the inner peripheral surface 1c. Around the support electrode 8 in the lid body 9, an exhaust port 1b and a plurality of air supply ports 1a facing the respective gas introduction ports 12a are formed.

In such a hard carbon film production apparatus, the film material gas G is supplied through the plurality of gas supply ports 12b, so that the gas density between the vacuum chamber 1 and the surface of the base material 6 on which the film is formed and Since the plasma density and the like become more uniform and stable at each site, the hard carbon film is formed on the end surface 6b and the outer peripheral surface 6a of the base material 6 in a state in which the hardness, composition, structure, adhesion, etc. are more uniform. And, it is formed at high speed. (Embodiment 3) FIG. 3 shows the configuration of a hard carbon film manufacturing apparatus in Embodiment 3 of the present invention.

In this hard carbon film production apparatus, a plurality of vacuum chambers 1 as shown in FIG. 1 are connected in parallel to a single exhaust device 10, a gas supply source 11 and a power source 4. As a result, the film forming conditions such as gas density and plasma density are equalized in each vacuum chamber 1, and uniform film formation can be performed on each substrate 6 installed in each vacuum chamber 1. (Embodiment 4) FIG. 4 shows the configuration of a hard carbon film manufacturing apparatus according to Embodiment 4 of the present invention.

In this hard carbon film manufacturing apparatus, the vacuum chamber 1
Corresponds to the disk-shaped conductive base material 6 having one surface (hereinafter referred to as the top surface 6c) as the film formation surface, and the top surface 6c of the base material 6 is
Has a similar inner surface shape (here, a bottomed cylindrical inner surface shape that is substantially similar to the outer shape of the base material 6), and is designed to form an equal gap with the upper surface 6c. The air supply port 1a so that it is opened slightly above the upper surface 6c of each of the two sides of the diameter.
And an exhaust port 1b are formed.

Further, the vacuum chamber 1 has a lid 9 in which the base material 6 is supported by the support electrodes 8 in order to make the exhaust volume as small as possible.
In the state where the base material 6 is mounted, the space between the top surface 1d of the vacuum chamber 1 and the top surface 6c of the base material 6 is designed to be as narrow as possible while securing a space capable of generating plasma. An airtight discharge space is formed between and.

The vacuum chamber 1 has a top surface 1 so that plasma is not generated between the inner surface 1c and the outer surface 6a of the substrate 6.
The inner peripheral surface 1c and the outer peripheral surface 6a of the substrate 6 are formed to have a longer distance than the distance between d and the upper surface 6c of the substrate 6. Further, an insulating member 8 a is arranged on the inner surface of the lid body 9 facing the lower surface of the substrate 6 so as to surround the outer periphery of the support electrode 9. As the insulating member 8a, an insulating glass made of tetrafluoroethylene polymer, alumina, quartz glass, or the like is used.

When a hard carbon film is manufactured by such a hard carbon film manufacturing apparatus, the base material 6 is placed inside the vacuum tank 1 and then the vacuum tank 1 is manufactured in the same manner as in the above-described embodiments. The inside of the chamber is evacuated to 10 ⁻² to 10 ⁻⁵ torr or less, and then the film material gas G is introduced to a predetermined pressure. Then, after confirming that the gas pressure and the gas flow rate in the vacuum chamber 1 have been stabilized at a predetermined value, for example, a pressure of about 10 ^-1 to 10 ^-3 torr or less, the power source 4 passes through the support electrode 8 and the substrate. 6 to 100
By applying a predetermined high frequency voltage within the range of up to 1000 W, plasma P is generated between the top surface 1d of the vacuum chamber 1 and the top surface 6c of the base material 6.

By doing so, the hardness, composition and structure of the upper surface 6c of the base material 6 are increased by the chemical reaction occurring in the plasma P between the top surface 1d of the vacuum chamber 1 and the upper surface 6c of the base material 6. Further, a hard carbon film having uniform adhesion and the like is formed at high speed. The hard carbon film is not formed on the outer peripheral surface 6a or the lower surface of the base material 6 which does not require film formation due to the presence of the insulating member 8a. (Embodiment 5) FIG. 5 shows the configuration of a hard carbon film manufacturing apparatus in Embodiment 5 of the present invention.

The hard carbon film manufacturing apparatus of this embodiment is shown in FIG.
It has the same structure as the hard carbon film manufacturing apparatus shown in, but a hollow part 12 is formed in the upper part of the main body 7 of the vacuum chamber 1,
A plurality of gas inlets 12a are formed on the upper surface so as to reach the hollow portion 12, and the gas inlets 12b from the hollow portion 12 are opposed to the film-forming surface of the substrate 6, that is, the top surface. The difference is that a plurality of them are formed at regular intervals so as to open in 1d.

By forming a plurality of gas supply ports 12b in this way, the film material gas is uniformly distributed and diffused, and the gas density and plasma between the vacuum chamber 1 and the film formation surface of the substrate 6 are increased. Since the density and the like becomes more uniform and stable at each site, the hard carbon film is formed on the upper surface 6c of the base material 6 at a high speed with the hardness, composition, structure, adhesion and the like being more uniform over the entire surface. To be done.

The vacuum chamber 1 corresponding to such a plate-shaped substrate 6 is also a single exhaust device as in the third embodiment.
By connecting a plurality of gas supply sources and power sources in parallel, a uniform film can be formed on each substrate 6 installed in each vacuum chamber 1.

As the power source 4, a DC power source or the like can be used instead of the above high frequency power source. When using a DC power supply, for example, a negative voltage is applied to the support electrode 8 and a ground potential and a positive voltage are applied to the main body 7 of the vacuum chamber 1. The applied voltage, the kind of gas in the vacuum chamber, the gas pressure, etc. can be changed as appropriate.

[0039]

As described above, according to the present invention, the substrates to be film-formed are individually housed in a vacuum chamber having an inner surface shape similar to that of the film-forming surface. By adopting a configuration in which a voltage is applied during the period, it becomes possible to shorten the exhaust treatment time and to uniformly form a film on a plurality of film formation surfaces at the same time. Therefore, mass productivity is improved, and it is possible to provide the rotary shaft, the plate-shaped substrate, and the like that form the slide bearing at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a hard carbon film manufacturing apparatus according to Embodiment 1 of the present invention, which is a hard carbon film manufacturing apparatus corresponding to a cylindrical base material.

FIG. 2 is a cross-sectional view showing a hard carbon film manufacturing apparatus according to Embodiment 2 of the present invention, which is another hard carbon film manufacturing apparatus corresponding to a cylindrical base material.

FIG. 3 is a cross-sectional view showing a hard carbon film manufacturing apparatus according to Embodiment 3 of the present invention, the hard carbon film manufacturing apparatus including a plurality of vacuum tanks.

FIG. 4 is a cross-sectional view showing a hard carbon film manufacturing apparatus according to Embodiment 4 of the present invention, the hard carbon film manufacturing apparatus corresponding to a plate-shaped substrate.

FIG. 5 is a cross-sectional view showing a hard carbon film manufacturing apparatus according to Embodiment 5 of the present invention, which is another hard carbon film manufacturing apparatus corresponding to a plate-shaped substrate.

FIG. 6 is a sectional view showing a conventional hard carbon film manufacturing apparatus.

7 is a cross-sectional view illustrating two steps of forming a hard carbon film on a base material that serves as a rotating shaft by the hard carbon film manufacturing apparatus of FIG.

[Explanation of symbols]

1 vacuum tank 1a Air supply port 1b exhaust port 1c Inner surface 1d top 4 power supply 6 base material 6a outer peripheral surface 6b end face 6c upper surface 8 Support electrodes 8a Insulation member 10 exhaust system 11 Gas supply source 12 Hollow part 12b gas supply port G Membrane material gas P plasma

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Inomoto             1 Juden Matsushita, 1-8 Koshinmachi, Takamatsu City, Kagawa Prefecture             Child Industry Co., Ltd. F-term (reference) 4K030 AA09 AA10 BA27 FA03 KA08                       LA23

Claims (6)

[Claims] 1. A vacuum chamber connected to an evacuation unit is provided with a support electrode for supporting a substrate to be film-formed, and a gas supply unit for supplying a film material gas into the chamber, and the vacuum chamber and a support. In a hard carbon film manufacturing apparatus configured to form a carbon hard film by a plasma CVD method on the base material having conductivity by connecting a power supply for applying a voltage between the electrodes, the vacuum chamber, An apparatus for producing a hard carbon film, which has an inner surface shape similar to that of the film-forming surface of the substrate and is configured to form an equal gap between the film-forming surface and the film-forming surface. 2. The hard carbon film manufacturing apparatus according to claim 1, wherein the gap between the inner surface of the vacuum chamber and the film formation surface of the substrate is 2 to 20 mm. 3. The hard carbon film manufacturing apparatus according to claim 1, wherein a plurality of gas inlets connected to the gas supply means are opened on the inner surface of the vacuum chamber facing the film formation surface of the substrate. 4. The hard carbon film manufacturing apparatus according to claim 1, wherein an insulating member is arranged to cover the non-film-forming target surface of the base material. 5. A plurality of vacuum chambers are connected in parallel.
The hard carbon film manufacturing apparatus described. 6. When a carbon hard film is formed on a conductive base material by a plasma CVD method, a vacuum chamber having an inner surface shape similar to the film formation surface of the base material is provided between the inner surface and the vacuum tank. The base material is supported by a supporting electrode so as to form an equal gap in each part, and a voltage is applied between the vacuum chamber and the supporting electrode while supplying a film material gas to a predetermined pressure. The method for producing a hard carbon film, wherein a carbon hard film is formed on the surface of the base material by generating plasma by the plasma.