JPH08193268A - Thin film forming method and apparatus - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a technique for efficiently forming a film having a small variation in film thickness. A method for forming a thin film by an ECR microwave plasma CVD method, comprising a step of supplying a thin film forming raw material into a reaction tube, and a step of irradiating the thin film forming raw material in the reaction tube with microwaves, A method for forming a thin film, in which an applied microwave is intermittently controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for forming a protective thin film such as a diamond-like carbon film provided on a recording medium such as a magnetic recording medium.

[0002]

BACKGROUND OF THE INVENTION Due to the demand for high-density recording, magnetic recording media such as magnetic tapes are not coated with a binder resin as a magnetic film provided on a non-magnetic support, but a binder resin. A metal thin film type that is not used has been proposed. That is, there has been proposed a magnetic recording medium having a magnetic layer formed by a wet plating means such as electroless plating or a dry plating means such as vapor deposition, sputtering or physical vapor deposition (PVD) such as ion plating. Since the magnetic recording medium of this type has a high packing density of magnetic material, it is suitable for high-density recording.

By the way, since the metal magnetic film in this kind of metal thin film type magnetic recording medium is poor in durability due to sliding with the magnetic head, surface oxidation treatment is carried out to provide a protective film by an oxide film. It is being appreciated. However, the surface oxidation means has little effect of improving the durability, and further studies have been conducted.

From this point of view, it has been proposed to provide a protective film of carbon, particularly diamond-like carbon, instead of a surface oxide film. For example, CH ₄ or C ₆ H ₆ gas as a carbon source is supplied to a chemical vapor deposition (CVD) apparatus, and plasma gas from this is deposited on the surface of the metal magnetic film to protect the surface from diamond-like carbon. A magnetic recording medium provided with a film has been proposed (JP-A-6-41758).

As such a CVD apparatus, there is an ECR microwave plasma CVD apparatus. However, the film formed by using the ECR microwave plasma CVD apparatus was found to have variations in film thickness.

[0006]

DISCLOSURE OF THE INVENTION As a result of earnestly studying the above-mentioned problems, as a result of the variation in film thickness, molecules or atoms having a charge are generated during film formation by ECR microwave plasma CVD, which causes an electrode or substrate. I got the revelation that it might be due to the fact that the electric discharge was caused by charging.

Therefore, as a result of a study on how to suppress the generation of charged molecules and atoms, it was found that the microwave to be applied should be intermittent. I got it. In other words, I thought that if microwaves were made intermittent, excessive energy-energy excitation would be suppressed, and the generation of charged molecules and atoms would be suppressed.

The present invention has been accomplished based on this finding, and an object of the present invention is to provide a technique for efficiently forming a film having a small variation in film thickness. An object of the present invention is a method of forming a thin film by an ECR microwave plasma CVD method, which comprises a step of supplying a thin film forming raw material into a reaction tube and a step of irradiating the thin film forming raw material in the reaction tube with a microwave. The present invention is achieved by a thin film forming method, which comprises intermittently controlling the applied microwave.

The intermittent control of the microwave is performed by intermittently absorbing the microwave radiated in the reaction tube with the microwave absorbing material. In particular, if the microwave absorber is driven so that the microwave is intermittently controlled, the stirring operation in the reaction tube is performed at the same time, and the homogenization is performed, so that a more uniform film is formed. Become so.

Another object of the present invention is an apparatus for forming a thin film by the ECR microwave plasma CVD method, which comprises a vacuum chamber, a support on which the thin film is formed, a supply means for this support and a winding device. Means, a plasma reaction tube provided so as to face a support running path in the vacuum chamber between the supply means and the winding means, a supply means for supplying a thin film forming raw material into the plasma reaction tube, A microwave oscillator for irradiating a microwave toward a thin film forming raw material in a plasma reaction tube, a microwave absorber provided in the plasma reaction tube for absorbing microwaves from the microwave oscillator, and the microwave absorber And a driving means for intermittently controlling the microwave to be applied.

If the microwave absorbing member is formed into a blade type and is rotated, the microwave is intermittently controlled and the stirring operation in the reaction tube is performed, so that the microwave can be made uniform and more uniform. Film is formed. The thin film formed by the present invention includes a carbon film, SiO _x ,
_{TiO x, BN, Si 3 N} 4 and the like. When a carbon film (particularly a diamond-like carbon film) is formed, as a thin film forming raw material (carbon compound), for example, chain hydrocarbons such as methane and n-hexane, cyclic hydrocarbons such as benzene, toluene and cyclohexane, Pyrazine,
Nitrogen-containing cyclic hydrocarbons such as pyrazole, pyridine, pyridazine, pyrimidine, piperidine, piperazine, imidazole and pyrrole are used. Of course, other materials may be used.

At the time of ECR microwave plasma CVD
Is a reaction gas used in combination with the above hydrocarbons.
Thus, an etching gas such as hydrogen or oxygen is used. So
Then, the stage where the thin film forming raw material was supplied into the plasma reaction tube
Microwaves are radiated on the floor to turn it into plasma. Teru
Microwave absorption to make the emitted microwaves intermittent
Wood is used. Ferrite as a microwave absorber
There is wood. For example, MOFe₂O₃(M is metal)
There is a ferrite material. Specifically, CoOFe₂O
₃, Fe_FourO ₃, MnZn ferrite, CuZn ferrite
Light, NiZn ferrite, CuZnMg ferrite
And so on. Rotating blades using such ferrite material
Root (1 or 2 or more blades), especially electric fan
I made a rotary blade with a blowing function like the blade of
A predetermined rotation mechanism is installed on the blades of the
If it is configured in the
Rukoto can.

With this structure, the generation of charged molecules and atoms is suppressed, and
Since the stirring is performed, a uniform film is formed. Further, since the generated plasma is pushed forward by the rotary blades, the film forming speed is also increased. The present invention is particularly applicable to a metal thin film type magnetic recording medium. That is, polyester such as PET, polyamide, polyimide, polysulfone, polycarbonate, olefin resin such as polypropylene, cellulose resin, polymer material such as vinyl chloride resin, inorganic material such as glass or ceramic, etc. On the support, for example, Fe, Co,
Other than metals such as Ni, Co-Ni alloy, Co-Pt alloy, Co-Ni-Pt alloy, Fe-Co alloy, Fe-N
i alloy, Fe-Co-Ni alloy, Fe-Co-B alloy,
It is applied to a magnetic recording medium in which a Co—Ni—Fe—B alloy, a Co—Cr alloy, or metal magnetic particles containing a metal such as Al contained therein is deposited by a dry plating means such as vapor deposition or sputtering. That is, the present invention is used when forming the protective film on the metal magnetic film. For example, 20
The present invention is used when forming a diamond-like carbon film having a thickness of up to 500Å on a metal magnetic film.

The present invention will be described below with reference to specific examples.

[0015]

1 is a schematic view of a magnetic recording medium manufacturing apparatus (ECR microwave plasma CVD apparatus) according to the present invention, and FIG. 2 is a schematic view of a main portion (rotary blade). In each figure, 1 is
It is a support such as a PET film provided with a metal magnetic film. This metallic magnetic film (2000-Å thick Co-Ni (8
0% -20%) alloy magnetic film) having a thickness of 2 to 50 μm, for example 6 μm, and provided on one surface of a non-magnetic support such as a PET film having a centerline average roughness Ra1 nm by using an oblique vapor deposition apparatus. It is a thing. The magnetic film has an in-plane coercive force of 160
0 Oe, in-plane saturation magnetization 6000 Gauss, squareness ratio 0.
It was 9.

The support 1 is arranged so that it can travel from the supply-side roll 3a arranged in the vacuum chamber 2 to the winding-side roll 3b via the cooling can roll 4. 5 is an ECR microwave plasma CVD apparatus. 6 is a plasma reaction tube, 7 is a microwave oscillator of 2.45 GHz and 600 W, 8 is an isolator, 9 is a power monitor, 10
Is a stub tuner, 11 is a coil, 12 is a container for filling hydrocarbons such as methane, and 13 is a mass flow controller (MFC).

Reference numeral 14 is a rotary ring having a gear on its outer periphery, which is arranged on the microwave inlet side in the plasma reaction tube 6, and 15
Is a drive gear that meshes with the outer peripheral gear of the rotating ring 14, 16
Is a blade attached to the rotating ring 14. The drive gear 15 that is rotated by the force of a drive motor (not shown)
The rotating ring 14 is rotated by this, and the gas in the plasma reaction tube 6 is pushed forward (on the side of the support 1) by the force of the rotating blade 16. Further, since the blade 16 is made of a microwave absorbing material such as ferrite (CoOFe ₂ O ₃ ) or the like, when the microwave from the microwave oscillator 7 hits the blade 16, it is absorbed. Therefore, since this microwave is cut off there, the microwave radiated in front of it becomes intermittent.

A protective film was formed on the metal magnetic film of the original magnetic recording medium using the above-mentioned apparatus. That is, using the ECR microwave plasma CVD apparatus shown in FIG.
A diamond-like carbon film was deposited to a thickness of 100 Å on a metal magnetic film on a 0 mm support. The reaction gases (CH ₄ and H ₂ ) introduced during this CVD were 100 sccm each, and were introduced into the plasma reaction tube 6 from the position behind the blade 16. Also, from the supply side roll 3a-
The running speed of the magnetic recording medium stock that was run on the winding side roll 3b via the cooling can roll 4 cooled to 10 ° C. was 2 m / min, and the degree of vacuum in the vacuum chamber 2 was 4 × 10.
^-3 Torr. The rotation speed of the blade 16 is 1000
rpm.

The diamond-like carbon film obtained as described above was examined by Auger spectrum. The result is shown in FIG. 3 (variation of thickness in the width direction at a position of 500 m after forming the diamond-like carbon film). And Table-1 (variation in thickness in the longitudinal direction at the center position in the width direction). Further, a diamond-like carbon film was formed by an apparatus obtained by removing the rotary ring with the blades 16 from the apparatus of FIG. 1, and this was examined by Auger spectrum. The results are shown in FIG. 3 and Table-1.
Shown in

Table-1 0m 100m 300m 600m 800m 900m Example-2 Å -4 Å -8 Å +2 Å +2 Å +4 Å Comparative example +2 Å +15 Å +13 Å +5 Å -3 Å * 6 Å * If the invention is set, this is -6 Å. It can be seen that the diamond-like carbon film produced by using the above device has excellent thickness uniformity. That is, in the longitudinal direction, the difference between the maximum thickness and the minimum thickness of the diamond-like carbon film is only 12 Å in the case of this embodiment, whereas the intermittent control of the irradiation microwave by the rotary blade is performed. In the case of the comparative example which did not exist, there is 21Å. Further, even in the width direction, the difference between the maximum thickness and the minimum thickness of the diamond-like carbon film is only 6 Å in the case of this embodiment, while the intermittent control of the irradiation microwave by the rotary blade is performed. In the case of the comparative example which was not performed, there is 18Å. That is, according to the present invention, a thin film having a uniform thickness can be formed.

[0021]

[Effect] According to the present invention, a uniform film can be formed.

[Brief description of drawings]

FIG. 1 is a schematic view of a magnetic recording medium manufacturing apparatus according to the present invention.

FIG. 2 is a perspective view of an essential part of the present invention.

FIG. 3 is a graph showing variation in the width direction of the diamond-like carbon film thickness.

[Explanation of symbols]

 1 Support Provided with Metallic Magnetic Film 2 Vacuum Tank 4 Cooling Can Roll 5 ECR Microwave Plasma CVD Device 6 Plasma Reaction Tube 7 Microwave Oscillator 11 Coil 14 Rotating Ring 15 Drive Gear 16 Blade

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junko Ishikawa 2606 Akabane, Kai-cho, Haga-gun, Tochigi Prefecture Kao Corporation Company Information Science Laboratory

Claims (5)

[Claims] 1. A method for forming a thin film by an ECR microwave plasma CVD method, comprising: a step of supplying a thin film forming raw material into a reaction tube; and a step of irradiating the thin film forming raw material in the reaction tube with microwaves. A method for forming a thin film, which comprises intermittently controlling the applied microwave. 2. The method for forming a thin film according to claim 1, wherein the intermittent control of the microwave is performed by intermittently absorbing the microwave applied to the reaction tube with a microwave absorbing material. 3. The microwave absorber is driven, whereby the microwave is intermittently controlled, and
The thin film forming method according to claim 2, wherein a stirring operation in the reaction tube is performed. 4. An apparatus for forming a thin film by the ECR microwave plasma CVD method, comprising a vacuum chamber, a support on which the thin film is formed, a supply means and a winding means for the support, and the supply means. A plasma reaction tube provided opposite to the support traveling path in the vacuum chamber between the winding means, a supply means for supplying a thin film forming raw material into the plasma reaction tube, and a thin film forming raw material in the plasma reaction tube Microwave irradiator for irradiating microwaves toward the target, a microwave absorber provided in the plasma reaction tube for absorbing microwaves from the microwave oscillator, and the microwave absorber is driven and irradiated. A thin film forming apparatus, comprising: a driving unit that intermittently controls microwaves. 5. The thin film forming apparatus according to claim 4, wherein the microwave absorbing material is a rotary blade that absorbs microwaves, and the driving means is a rotating means.