JP3358352B2 - Film forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus suitable for forming a protective film on a non-magnetic support having a magnetic layer by a so-called continuous winding method.

[0002]

2. Description of the Related Art Conventionally, magnetic recording media capable of coping with high-density magnetic recording include Co-Ni alloys and Co-Cr alloys.
A metal magnetic material such as an alloy or Co-O is directly coated on a non-magnetic support such as a polyester film, a polyamide or a polyimide film by plating or a vacuum thin film forming means (a vacuum deposition method, a sputtering method, an ion plating method, etc.). A so-called metal magnetic thin film type magnetic recording medium is known.

The magnetic recording medium of this metal magnetic thin film type is excellent in coercive force, squareness ratio and the like, and the thickness of the magnetic layer can be made extremely thin. In addition to excellent conversion characteristics, the magnetic layer has a number of advantages such as a higher packing density of the magnetic material because it is not necessary to mix a binder, which is a nonmagnetic material, in the magnetic layer. Due to such superiority in magnetic properties, the metal magnetic thin film type magnetic recording medium is becoming the mainstream of high density magnetic recording.

[0004] In the magnetic recording medium of the metal magnetic thin film type, the medium tends to be smoothed in order to reduce the spacing loss from the flow of high density. As the smoothing of the medium proceeds, the frictional force between the head and the medium increases, and the shear stress generated in the medium increases.

In order to cope with this severe sliding durability, a carbon film or quartz (SiO ₂ ) is formed on the surface of the magnetic layer.
A technique for forming a protective film made of a film, a zirconia (ZrO ₂ ) film, or the like has been studied. As this protective film, in particular, a diamond-like carbon (DLC) film, which is a harder film among carbon films, has recently been considered promising.

[0006]

As a method for forming the diamond-like carbon (DLC) film, for example, a sputtering method, a CVD method, or the like is used.

In the sputtering method, first, an inert gas such as an Ar gas is ionized (plasmaized) using an electric field or a magnetic field. Then, by accelerating the ionized Ar ions, target atoms are repelled by their kinetic energy. Subsequently, the ejected atoms are deposited on a substrate disposed opposite to the target to form a target film.

When the diamond-like carbon (DLC) film is formed by this process, the film formation speed is generally slow, and the productivity is poor from an industrial viewpoint.

On the other hand, in the CVD method, a chemical reaction such as decomposition or synthesis of a gas as a raw material is caused by utilizing energy of plasma generated by using an electric field or a magnetic field to form a film. Process.

The CVD method has a higher film formation rate than the sputtering method, and is expected as a means for forming the diamond-like carbon (DLC) film in the future.

However, in the case of using a reaction tube in this CVD method, there is a point that the film formation is more difficult than in the case of the above-mentioned sputtering method, and it is said that practical use is difficult. The difficulty is that, for example, the gap between the reaction tube and a cylindrical electrode arranged opposite to the reaction tube needs to be constantly controlled on the order of millimeters. If the management of the distance between the reaction tube and the electrode is inappropriate, the resulting film may have unevenness in film thickness or the like, resulting in a product having significant defects.

As a method for solving this problem, there is known a method of managing the gap by using a detector as described in, for example, Japanese Patent Application Laid-Open No. 4-9474. However, although this method is excellent as a method for managing the gap, it has to provide a feedback circuit and a mechanism for moving the reaction tube up and down, and has a drawback that the apparatus becomes complicated.

Accordingly, the present invention has been proposed in view of such circumstances, and a film forming apparatus capable of well managing a gap between a reaction tube and an electrode and suppressing unevenness in film thickness has been proposed. The purpose is to provide.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, provided a rotating roll at the tip of a reaction tube so as to be in contact with a cylindrical electrode. By making the gap with the reaction tube mechanically constant according to the diameter of the rotating roll, it has been found that unevenness in film thickness can be suppressed and a product with less variation can be manufactured, leading to the completion of the present invention. It is a thing.

That is, in the film forming apparatus of the present invention, a cylindrical electrode in which a non-magnetic support runs along the outer peripheral surface and a reaction tube in which a raw material gas is introduced and a film is formed are formed in a vacuum chamber. And a rotating roll that is arranged opposite to the inside of the inside and is in contact with the cylindrical electrode at the tip of the reaction tube.

As a constituent material of the rotary roll, for example, metal may be used, but an insulator such as a quartz tube, Pyrex glass, or plastic is more preferable.

It is desirable that the run-out of the rotating roll be within 5 mm.

Further, it is desirable that a partition plate which spatially separates from the rotating roll is disposed in the reaction tube.

The film forming apparatus of the present invention is suitable for use mainly in producing a magnetic recording medium. The magnetic recording medium to be used here is a so-called metal magnetic thin film type magnetic recording medium in which a metal magnetic thin film is formed as a magnetic layer on a non-magnetic support by a vacuum thin film forming technique.

In the above magnetic recording medium of the metal magnetic thin film type, the nonmagnetic support and the metal magnetic material constituting the metal magnetic thin film can be any of those conventionally used in this type of magnetic recording medium. And is not particularly limited.

More specifically, examples of the metallic magnetic material include ferromagnetic metals such as Fe, Co, and Ni;
Co-O, Fe-Co-Ni, Fe-Cu, Co-C
u, Co-Au, Co-Pt, Mn-Bi, Mn-A
1, Fe-Cr, Co-Cr, Ni-Cr, Fe-Co
Ferromagnetic alloys such as -Cr, Co-Ni-Cr, and Fe-Co-Ni-Cr;

These films may be single-layer films or multilayer films.

In order to improve the adhesion between the non-magnetic support and the metal magnetic thin film, or in the case of a multilayer film, and to control the coercive force, an underlayer or an intermediate layer is formed. May be provided. Furthermore, for example, the vicinity of the surface of the magnetic layer may be made of an oxide for improving corrosion resistance and the like.

Means for forming the metal magnetic thin film include a vacuum evaporation method in which the above-described metal magnetic material is heated and evaporated under vacuum to be deposited on the non-magnetic support, and a method in which the evaporation of the metal magnetic material is carried out during discharge. Ion plating method,
A so-called PVD technique such as a sputtering method in which atoms on the target surface are beaten by argon ions generated by causing glow discharge in an atmosphere containing argon as a main component can be used.

A protective film is formed on the metal magnetic thin film by a CVD method.

As the protective film, for example, a diamond-like carbon (DLC) film is suitable.

Of course, the configuration of the magnetic recording medium to which the present invention is applied is not limited to this, but may be changed without departing from the scope of the present invention, for example, forming a back coat layer as necessary. Or forming an undercoat layer on the nonmagnetic support or forming various layers such as a lubricant layer. In this case, as the nonmagnetic pigment and the resin binder contained in the back coat layer, or the material contained in the lubricant layer, any of conventionally known materials can be used.

[0028]

When a film is formed by a CVD method while a non-magnetic support is moved along the outer peripheral surface of a cylindrical electrode, the electrode comes into contact with the tip of a reaction tube into which a raw material gas is introduced. When the rotating roll is disposed as described above, the gap between the electrode and the reaction tube is mechanically kept constant according to the diameter of the rotating roll. Thereby, the thickness unevenness of the obtained film is significantly suppressed.

[0029]

EXAMPLES The present invention will be described below with reference to specific examples, but it goes without saying that the present invention is not limited to these examples.

First, when producing a magnetic tape according to this embodiment, the plasma C used in the process of forming the protective film was used.
The configuration of the VD continuous film forming apparatus will be described.

As shown in FIG. 1, this plasma CVD continuous film forming apparatus is an object to be processed in a vacuum chamber 13 whose inside is maintained at a predetermined vacuum degree by an exhaust system 12 mounted on the head. The tape-shaped non-magnetic support 1 is shown in FIG.
The feeding roll 3 rotates at a constant speed in the counterclockwise direction and the winding roll 4 rotates at a constant speed in the counterclockwise direction.

On the non-magnetic support 1, a ferromagnetic metal thin film partially oxidized by vapor deposition of Co while introducing oxygen gas is formed.

In the middle of the travel of the non-magnetic support 1 from the feed roll 3 side to the take-up roll 4 side,
The non-magnetic support 1 is provided so as to be drawn downward in FIG. 1, and the counter electrode 11 having a diameter larger than the diameter of each of the rolls 3 and 4 is rotated at a constant speed in a clockwise direction in FIG. Is provided.

The feed roll 3 and the counter electrode 11
Guide rolls 2a and 2b are provided between the counter electrode 11 and the take-up roll 4, respectively. The guide rolls 2a and 2b are disposed between the feed roll 3 and the counter electrode 11, and travel between the counter electrode 11 and the take-up roll 4. The non-magnetic support 1 is provided with an appropriate tension so that the non-magnetic support 1 can run smoothly.

The feed roll 3, the take-up roll 4, and the counter electrode 11 each have a cylindrical shape having a length substantially equal to the width of the nonmagnetic support 1.

Accordingly, in this plasma CVD continuous film forming apparatus, the non-magnetic support 1 is sequentially sent out from the feed roll 3, passes along the outer peripheral surface of the counter electrode 11, and further passes through the winding roll. 4 and so on.

On the other hand, a reaction tube 5 is provided in the vacuum chamber 13 below the counter electrode 11. This reaction tube 5
Is used to decompose and synthesize a raw material gas mainly composed of a hydrocarbon gas introduced from a discharge gas inlet port 7 provided at the bottom, and to provide a nonmagnetic support between the reaction tube 5 and the counter electrode 11. When the body 1 passes, a protective film is formed on the magnetic layer formed on the nonmagnetic support 1.

As a material of the reaction tube 5, a quartz tube having an insulating property, Pyrex glass, plastic or the like is suitable.

Inside the reaction tube 5, the vacuum tank 13
+500 to 200 by DC power supply 9 arranged outside
An electrode 8 to which a potential of 0 V is applied is incorporated.

The electrode 8 is required to be made of a material which is easy to transmit gas, can apply an electric field uniformly, and has high flexibility. For example, a metal mesh such as a wire mesh is preferable. . As a constituent material of such an electrode 8, for example, copper or the like is typical, but for example, gold or the like can be used in terms of conductivity.

A rotating roll 6 is attached to the tip of the reaction tube 5 so as to be in contact with the outer peripheral surface of the counter electrode 11. The rotating roll 6 is pressed against the outer peripheral surface of the counter electrode 11 by a spring support 14 inserted around the discharge gas inlet 7 provided at the bottom of the reaction tube 5. The gap with the reaction tube 5 is kept constant according to the diameter of the rotating roll 6.
Thereby, the reproducibility of the film thickness of the obtained film becomes good,
Products with little variation can be manufactured.

The material of the rotating roll 6 may be a metal or the like in terms of machining accuracy. However, since abnormal discharge or the like is likely to occur, it is more desirable to use the reaction tube 5 as described above.
Similarly to the above, an insulator such as a quartz tube, Pyrex glass, or plastic may be used.

The run-out of the rotating roll 6 is 5 mm.
It is desired to be within. If the run-out of the rotating roll 6 is larger than 5 mm, the gap between the counter electrode 11 and the reaction tube 5 changes, and not only the thickness of the obtained film is not constant but also the discharge may be unstable. Occurs.

As shown in FIGS. 2 and 3, a partition plate 10 is provided in the reaction tube 5 so that the inside of the reaction tube 5 and the rotary roll 6 are spatially separated. Are separated. Thereby, the product generated inside the reaction tube 5 is configured not to be deposited on the rotating roll 6.

Then, using a plasma CVD continuous film forming apparatus having such a configuration, a vapor deposition tape was produced as follows.

First, a C film was formed on a base film made of polyethylene terephthalate having a thickness of 10 nm by oblique evaporation.
A metal magnetic thin film made of an o ₈₀ Ni ₂₀ (numerical value represents a composition ratio) alloy was formed so as to have a thickness of 200 nm, and a magnetic layer formed of a single-layer film was provided. The film forming conditions for the oblique deposition were as follows.

Incident angle: 45-90 ° Introduced gas: oxygen gas Degree of vacuum during vapor deposition: 2 × 10 ^-2 Pa Subsequently, the above-mentioned metal magnetic thin film was formed on the metal magnetic thin film using the plasma CVD continuous film forming apparatus shown in FIG. A diamond-like carbon film having a thickness of 10 nm was formed. This plasma CV
In performing D, the film forming conditions were as shown below.

Introduced gas: toluene Reaction pressure: 10 Pa Input power: DC 1.5 kV A sample tape prepared as described above and a plasma to which the above-mentioned reaction tube was directly attached without using the above-mentioned rotating roll for comparison. For a comparative tape on which the diamond-like carbon film was formed by a CVD apparatus, the reproducibility of the film thickness when the diamond-like carbon film was formed was examined.

FIG. 4 shows the result.

In FIG. 4, .largecircle. Indicates the result of this example, and X indicates the result of the comparative tape.

As is apparent from FIG. 4, when a rotating roll is disposed at the tip of the reaction tube as in this embodiment, and the rotating roll is pressed against the outer peripheral surface of the counter electrode, the film is formed. The variation was within ± 1 nm with respect to the set film pressure of 10 nm.

On the other hand, in the comparative example, the thickness unevenness was large, and good reproducibility could not be obtained. This is because there was variation in the setting of the reaction tube due to cleaning after film formation and the like, and the reproducibility of the gap with the counter electrode was good in the reaction tube according to the present invention, which was easy to position, whereas the comparative example This is because the reproducibility is poor.

As described above, the plasma CVD apparatus of the present invention, which can keep the gap between the counter electrode and the reaction tube constant in the order of millimeters, is very effective in forming a protective film.

[0054]

As is apparent from the above description, in the present invention, when a protective film is formed on a non-magnetic support having a magnetic layer by a CVD method, a rotating roll is attached to the tip of a reaction tube. Since the film is formed by pressing the rotating roll against the outer peripheral surface of the counter electrode, the gap between the counter electrode and the reaction tube can be kept constant in the order of millimeters, and the thickness unevenness can be suppressed. As a result, the reproducibility of the thickness of the obtained film is improved, and a product with less variation can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a plasma CVD apparatus used for forming a diamond-like carbon film when manufacturing a magnetic tape by applying the present invention.

FIG. 2 is a side view showing a configuration example of a reaction tube in the plasma CVD apparatus.

FIG. 3 is a front view showing a configuration example of a reaction tube in the plasma CVD apparatus.

FIG. 4 is a characteristic diagram showing a relationship between the number of experiments and a degree of variation from a set thickness of a protective film obtained.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-magnetic support body (object to be processed) 2a, 2b Guide roll 3 Feed roll 4 Take-up roll 5 Reaction tube 6 Rotating roll 7 Discharge gas inlet 8 Electrode 9 DC power supply 10 Partition plate 11 Counter electrode 12 Exhaust system 13 Vacuum tank 14 Spring support

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukari Yamada 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (56) References JP-A-6-41758 (JP, A) JP-A Heisei 4-9474 (JP, A) JP-A-4-103024 (JP, A) JP-A-63-279426 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/84 C23C 16/44

Claims (5)

(57) [Claims] A cylindrical electrode on which a non-magnetic support runs along an outer peripheral surface; and a reaction tube in which a raw material gas is introduced and a film is formed inside the cylindrical electrode, and the reaction tube is opposed to each other in a vacuum chamber. A film forming apparatus, wherein a rotating roll that contacts the cylindrical electrode is disposed at a tip of a tube. 2. The film forming apparatus according to claim 1, wherein the rotating roll is made of a metal or an insulator. 3. The film forming apparatus according to claim 1, wherein the rotating roll is made of a quartz tube, Pyrex glass, or plastic. 4. The film forming apparatus according to claim 1, wherein the run-out of the rotating roll is within 5 mm. 5. The film forming apparatus according to claim 1, wherein a partition plate for spatially dividing the rotating roll is provided in the reaction tube.