JP2000080475A - Formation of diamond like carbon film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a diamond like carbon film capable of forming a diamond like carbon film on the body to be treated at a high film forming rate regardless electric properties and thickness of the body to be treated and also without specially applying a bias to the body to be treated. SOLUTION: The inside of a reaction chamber C4 stored with the body to be treated is filled with a gaseous starting material contg. carbon atoms and hydrogen atoms under low pressure, and, in this reaction chamber, electron beams generated by a cathode electrode 14 and accelerated by an accelerating electrode 13 are made incident on the body to be treated, by which the body to be treated is negatively charged, and also, the electrons are collided with the molecules of the gaseous starting material to generate the radicals of hydrocarbon, and these radicals are absorbed into the negatively charged body to be treated to form a diamond like carbon film on the body to be treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cutting tool, a mold,
The present invention relates to a method for forming a diamond-like carbon film on a surface of a processing target such as a magnetic recording medium.

[0002]

2. Description of the Related Art In general, a diamond-like carbon film has properties such as chemical stability, high hardness and low friction, and is therefore used in various fields. The following four methods are generally known as methods for forming such a diamond-like carbon film.

(1) Hydrocarbon gas is thermally dissociated on the surface of a high-temperature filament to form radicals such as CH ₃ , which are deposited on an object to be processed, and at the same time, electrons emitted from the filament are accelerated. A diamond-like carbon film is formed on the object by releasing hydrogen atoms from the deposit on the object.

(2) Carbon ions are sputtered by applying an ion beam to graphite placed in hydrogen gas, and the carbon molecules are deposited on the object to be processed while containing hydrogen atoms to form a diamond-like carbon film. I do.

[0005] (3) A graphite placed in hydrogen gas is irradiated with a laser beam to ablate (ablate) carbon molecules to form a diamond-like carbon film. (4) A plasma of a mixed gas of hydrocarbon and hydrogen is generated, and carbon molecules are deposited on the object to which a high-frequency bias is applied to form a diamond-like carbon film.

In such a method, in any case, when the object to be processed is thin, for example, 1 mm or less, regardless of the electrical characteristics (conductive or insulating) of the object to be processed. In addition, a diamond-like carbon film can be relatively easily formed on a target object.

[0007]

However, in the method (1), since the film formation rate is very low and the filament surface is damaged, a high chemical activity such as fluorine gas for controlling the film quality is required. Gas cannot be used together.
In the methods (2) to (4), it is necessary to apply a bias voltage to the object to be processed. Therefore, when the object to be processed is an insulator, only a thin object can be used, and the versatility is poor.
Further, a power supply for applying a bias voltage is required.

Accordingly, an object of the present invention is to provide a diamond-like material on a processing object regardless of the electrical characteristics and thickness of the processing object and without applying a bias to the processing object. An object of the present invention is to provide a method for forming a diamond-like carbon film that can form a carbon film at a high film formation rate.

[0009]

A first aspect of the present invention.
In the method for forming a diamond-like carbon film described in the above, the reaction chamber containing the object to be processed is filled with a source gas containing low-pressure carbon atoms and hydrogen atoms, and the electron beam accelerated into the reaction chamber is applied to the object to be processed. The incident light charges the target object negatively and collides the electrons with the molecules of the source gas to generate hydrocarbon radicals, which are deposited on the surface of the target object to form a deposited film. Simultaneously, positive ions collide with the negatively charged object to be processed, and the hydrogen atoms in the deposited film are released by the effect to form a diamond-like carbon film on the object to be processed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for forming a diamond-like carbon film according to an embodiment of the present invention will be described below with reference to the accompanying drawings, together with an example of a forming apparatus. FIG. 1 shows an example of an apparatus for forming a diamond-like carbon film. Reference numeral 10 denotes a cylindrical housing formed of metal and extending horizontally, and the insides are arranged at a predetermined interval from each other. Three electrodes 1
According to 1, 12, and 13, four small rooms C _{1 in} order from the left side
It is divided into C ₄ to no. And these electrodes 1
A central opening is formed in each of 1, 12, and 13,
Adjacent small rooms communicate with each other through these openings. At one end of the first chamber C ₁ , a cathode electrode 14 is provided so as to face the opening of the first electrode 11.
A gas supply port 15 connected to a gas source for supplying Ar gas to the first small room is provided. Thus, the first chamber C ₁ functions as arcing chamber for generating an arc as the electron beam source.

The second to fourth small chambers C ₂ to C ₄ have exhaust ports 16 and 1 connected to an exhaust system, respectively.
7 and 18 are provided so that the pressure in each of the small rooms can be maintained in a predetermined reduced pressure state. Further, a support 19 for supporting an object to be processed is provided in the fourth small room C ₄ located on the rightmost side so as to face the opening of the third electrode 13. A gas supply port 20 connected to a hydrocarbon gas source and for supplying a hydrocarbon gas as a source gas to the fourth small chamber is provided.
Thus, this fourth chamber functions as a reaction chamber.

A filament power source _Vf is connected to the filament forming the cathode electrode 14 via an ammeter, and a first power supply is connected between the cathode electrode 14 and the first electrode 11. The arc discharge power supply _Vd is connected so that the electrode functions as an anode electrode. Also, the first and second electrodes 11 and 12 and the third electrode 13
Accelerating power source V _a is connected between the.

In the drawings, reference numerals 21 and 22 denote electromagnetic waves for regulating the radial diffusion of the electron beam in the housing 10 and generating a magnetic field so that the electron beam can efficiently pass through the opening of the electrode. Indicates a coil or permanent magnet.

In the above-described apparatus for forming a diamond-like carbon film, the first to third exhaust ports 16, 17, 1
After exhausting the inside of the housing 10 through 8, Ar gas is supplied to the first small room C ₁ through the port 15. The supply amount of the Ar gas in this case, A in the first small chamber in C ₁
The pressure of the r gas is set to be about 300 mTorr. As a result, an arc discharge is generated between the cathode electrode 14 and the anode electrode 11. This arcing, since than the first small chamber C ₁ is towards the second small chamber C ₂ is fairly low pressure, extending in a second small chamber in C ₂ through the opening of the first electrode 11 . In addition, the second small room C ₂
Because the pressure in the third small room C ₃ is lower than
The electrons of the arc column in the _second cell C ₂ are supplied to the second electrode 1
Through the second opening into the third small chamber C _3. And the third
In small room C _3, electrons are injected to the second electrode 12 is accelerated to the required energy by a potential difference between the third electrode to the fourth small chamber C _4. The pressure in the fourth small chamber C ₄ is set to about 10 ⁻³ Torr or a lower pressure in advance, so that the average free path of gas molecules is several centimeters or more, The mean free path after collision with gas molecules is considered to be 10-20 cm. Thus, a portion of the fourth small chamber is injected into the C ₄ electrons, diamond-like carbon to the fourth collide with advance of the hydrocarbon gas supplied through the port 20 molecules small chamber C ₄ Radicals such as CH ₃ necessary for film formation and ions having a density several orders of magnitude lower than these, such as CH ⁺ , are formed and thereby formed. Further, the remaining electrons proceed straight, enter the object to be processed, and negatively charge the object. As a result, a sheath is formed between the plasma and the object to accelerate the ions, and the ion bombardment of the diamond-like carbon film becomes more active. As a result, a diamond-like carbon film having high hardness can be formed on the object at a high film forming rate.
Incidentally, by adjusting the accelerating voltage between the second electrode 12 due to acceleration power supply V _a and the third electrode 13, diamond-like carbon by adjusting the energy of the electrons that are accelerated between these electrodes appropriately The film quality of the film can be easily controlled. Further, the film quality of diamond-like carbon film by the process gas supplied to the fourth small chamber C ₄ adding chemical highly active materials, such as F ₂ gas can be controlled. When F ₂ gas is added, the F ₂ gas has a strong corrosive property and may damage the surface of the filament constituting the cathode electrode 14.
Gas pressure in the first small chamber in C ₁ is considerably higher than the gas pressure in the fourth small chamber C _4, for example, 10 ² to 10 ⁴ times higher, and its magnitude of 10 ^-1 Torr Therefore, the first small room C ₁ is regarded as a viscous region, and F ₂
Gas molecules do not flow back into the _first compartment C1. Further, since the Ar gas supplied to the first small chamber in C ₁ to the arc discharge is an inert gas, nor filament is contaminated by the gas.

Example A film was formed on a glass plate as an object to be processed using the following parameters by using ethylene gas as a reaction gas, and the formed film was subjected to Raman analysis. Was confirmed to be a diamond-like carbon film.

1) Type of gas used Ethylene pressure 1.5 mTorr (directly read by ionization vacuum gauge) 2) Object to be processed Glass plate (76 × 26 × 1t) 3) Operating conditions Electron beam acceleration voltage Vac = 70 V Electron speed (5 × 10 ⁸ cm s ^-1) electron beam current Iac = 3A beam diameter D _b = Φ63.5mm beam cross-sectional area A _b = 31.7cm ² beam current density i _b = 100mA cm ^-2 beam electron density n _eb = 1. 3 × 10 ⁹ cm ^-3 4) deposition rate ^{_{R d = 17A ° s -1 5}} ) surface potential V _sfl = 50 V Figure 2 of the object of the film, the deformation of the forming apparatus of a diamond-like carbon film shown in FIG. 1 Here is an example. In this example, the porous electrodes 12a and 13a are used as the second and third electrodes, and electrons are accelerated between them. Therefore, the first and second exhaust ports are not required, and the inside of the housing 10 is exhausted only by the third exhaust port 18. Also in such an apparatus, the method for forming a diamond-like carbon film of the present invention can be carried out similarly to the apparatus shown in FIG.

In the above embodiment, Ar gas is used as the discharge gas. However, other gases can be used, and the reaction gas, that is, the raw material gas is not limited to ethylene gas. Any gas may be used as long as it contains a carbon atom and a hydrogen atom.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a diamond-like carbon film forming apparatus suitable for carrying out a method for forming a diamond-like carbon film according to the present invention.

FIG. 2 is a view schematically showing a diamond-like carbon film forming apparatus as a modification of the apparatus shown in FIG.

[Explanation of symbols]

Reference numeral 10: housing, 11.12.13: first, second, and third electrodes, 14: cathode electrode, C1 to C4: _first to _fourth small chambers, 19: support.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Manabu Hamagaki 2-1 Hirosawa, Wako-shi, Saitama F-term in RIKEN (Reference) 4G077 AA03 BA03 DB07 DB24 EG26 4K030 AA09 AA17 BA28 CA06 FA12 KA49 LA20 LA21 LA22

Claims (2)

[Claims] 1. A reaction chamber containing an object to be processed is filled with a low-pressure raw material gas containing carbon atoms and hydrogen atoms, and an accelerated electron beam is incident on the object to be processed into the reaction chamber. In addition, the workpiece is negatively charged and the electrons collide with the molecules of the source gas to generate hydrocarbon radicals, and these radicals are deposited on the surface of the workpiece to form a deposited film, and simultaneously negatively charged A method for forming a diamond-like carbon film on a target object by causing positive ions to collide with the target object and releasing hydrogen atoms in the deposited film by the effect. 2. The method according to claim 1, wherein a substance having a high chemical activity is supplied into the reaction chamber in a state where the pressure in the arc generation chamber for generating an arc serving as an electron beam source is higher than the pressure in the reaction chamber. Method for forming a diamond-like carbon film.