JPH0820866A - Thin film forming device - Google Patents

Abstract

PURPOSE:To uniformly hold the film thickness and film quality of a protective film in the case the thin film forming device is applied to the formation of a protective film in a magnetic tape and to produce a magnetic tape excellent in wear resistance at high yield. CONSTITUTION:In a thin film forming device in which a target 10 on a backing plate 11 as a cathode electrode is sputtered while a gas is introduced from a gas introducing port 16 to form a protective film on the surface of a burnable supporting body opposite to the target 10, the thin film forming face of the substrate and the face 10a of the target 10 to be sputtered opposite to the same are made to the vertical direction, and the gas introducing tube 16 is formed in the direction upper than a cathode unit 9 and in the direction rearer than the main face 15a of a cathode mask 15. Thus, the falling of the thin film material onto a cathode electrode and its falling onto the space between the target and substrate is hard to occur, and the generation of abnormal discharge is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus for forming a thin film on a substrate surface by a sputtering method, and more particularly to a thin film forming apparatus having a structure capable of suppressing abnormal discharge.

[0002]

2. Description of the Related Art Conventionally, vapor deposition, sputtering, CVD and the like have been studied as vacuum thin film forming methods and have been put to practical use in various fields. The vapor deposition method and the CVD method have a high film formation rate, and particularly, the vapor deposition method has an advantage that a high speed film formation is possible by using an EB gun. However, since this vapor deposition method is a method of vaporizing and depositing metal, there is a problem that it is difficult to simultaneously and stably deposit substances having different vapor pressures.

On the other hand, the sputtering method has attracted attention because it can form alloy films of various metals having different vapor pressures. For example, it is used for magnetic tapes used in digital video tape recorders, commercial video tape recorders and data storage. Application to the formation of a protective film in a magnetic recording medium such as a magnetic tape which requires extremely high durability has been studied. Specifically, SiO ₂ , SiN _x , C, S
It has been known that forming a wear resistant material such as iC as a protective film improves running durability and corrosion resistance of the magnetic recording medium.

Conventionally, the above-mentioned sputtering method has a problem in that it is inferior in productivity because it is inferior in film forming rate to the vapor deposition method, and the apparatus becomes large in size for mass production. Then, the film forming speed is increasing due to the development of the sputtering method such as the magnetron sputtering method and the facing target method. FIG. 5 shows a thin film forming apparatus to which the magnetron sputtering method is applied. In this thin film forming apparatus, a traveling system for traveling the flexible support 5 in the vacuum chamber 2 having the exhaust ports 1a and 1b, and the flexible support 5 are provided.
And a film forming system for forming a thin film. The traveling system includes a feed roll 3, a take-up roll 4, a cylindrical can 6, and guide rolls 7 and 8. The flexible support 5 is moved from the feed roll 3 by rotating at a constant speed in the direction of the arrow in the figure. After being sequentially fed out and run along the peripheral surface of the cylindrical can 6, the winding is performed on the winding roll 4.

On the other hand, the film forming system is provided below the vacuum chamber 2 which is partitioned by a partition plate, and the cathode unit 9 is provided below the cylindrical can 6, and the raw material of the thin film disposed on this surface. And a gas introduction pipe 16. The cathode unit 9 is shown in FIG.
As shown in the cross section, the backing plate 11, which is connected to a power source (not shown) and serves as a cathode electrode,
Magnets 12 and 13 arranged below the backing plate 11, a cathode case 14 for housing them,
Target 10 on the upper surface of the backing plate 11
Cathode mask 15 covering the area where the
Consists of. Further, the gas introduction pipe 16 is provided on the side of the cathode unit 9 and has a gas introduction port 16 a having a length substantially equal to the length of the cathode unit 9.

Then, in order to form a thin film by the apparatus having the above-mentioned structure, the backing plate 11 with the flexible support 5 running in the running system described above.
Supply a predetermined power to. As a result, a discharge is generated between the thin film material and the cylindrical can 6, and the gas supplied from the gas introduction pipe 16 is ionized and attacks the target 10, so that the thin film material is deposited on the surface of the flexible support 5. The stray magnetic field generated from the magnets 12 and 13 traps electrons to sustain discharge and enables efficient sputtering. Further, the area of the backing plate 11 where the target 10 is not provided is shielded from the attack of ions by the cathode mask 15.

[0007]

By the way, the thin film material knocked out from the target 10 adheres not only to the flexible support 5 but also to the inner wall of the vacuum chamber 2, the partition plate, the cathode unit 9 and the like. If it is deposited for a long time, it peels off and falls. The thin film material is the backing plate 1.
When it falls on the upper surface 1, abnormal electric discharge is caused, which causes problems such as making the film thickness of the thin film formed on the surface of the flexible support 5 nonuniform and causing abnormal film quality.

Therefore, the present invention has been proposed in view of such circumstances, and by suppressing abnormal discharge, for example, when applied to the formation of a protective film in a magnetic recording medium, the durability and rust prevention can be improved. An object of the present invention is to provide a thin film forming apparatus capable of forming a thin film with such a uniform film thickness and film quality.

[0009]

Means for Solving the Problems The present invention has been earnestly studied to achieve the above object, and as a result, the thin film forming surface of the flexible support and the target sputtered surface facing the thin film forming surface are vertically aligned. It was found that, by setting the above, the fall of the thin film material on the cathode electrode can be suppressed. Furthermore, it was found that preventing the thin film material from falling into the space between the target and the substrate in addition to the thin film material falling onto the cathode electrode is effective in suppressing abnormal discharge. He came to propose an invention.

That is, the thin film forming apparatus according to the present invention sputters a target disposed on the cathode electrode while introducing gas from the gas introducing pipe to form a thin film on the surface of the substrate facing the target. In the thin film forming apparatus to be formed, the thin film forming surface of the base body and the sputtered surface of the target facing the same are in the vertical direction, and the gas introducing pipe is a range of the cathode electrode surface where the target is not arranged. It is provided below and behind the cathode mask that covers.

As described above, when the thin film forming surface of the substrate and the sputtered surface of the target facing the substrate are in the vertical direction, the thin film material is prevented from falling onto the cathode electrode.
Furthermore, when the gas introduction tube is provided below and behind the cathode mask, the thin film material attached to the gas introduction tube will not drop into the space between the target and the substrate, and the occurrence of abnormal discharge can be further suppressed. Is possible.

By the way, the substrate on which a thin film is formed by the thin film forming apparatus of the present invention is preferably a flexible support in which a metal magnetic thin film is formed on a long film.
That is, the formed thin film is suitable as a protective film provided on the metal magnetic thin film in a so-called vapor deposition tape. In this case, any conventionally known material can be used as the material of the protective film, such as CrO ₂ , Al ₂ O ₃ and B.
N, Co oxide, MgO, SiO ₂ , Si ₃ O ₄ , Si
_{N x, SiC, SiN x -SiO} 2, ZrO 2, TiO
₂ , TiC and the like can be mentioned, but carbon is typical. Further, the protective film may be a single layer film of these, a multilayer film or a composite film with a metal.

When a vapor deposition tape is manufactured using the thin film forming apparatus according to the present invention, any conventionally known material can be used as the material for the metal magnetic thin film.
Ferromagnetic metal materials such as Fe, Co and Ni, Fe-Co and C
o-Ni, 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
Examples include ferromagnetic alloy materials such as -Cr, Co-Ni-Cr, and Fe-Co-Ni-Cr. The metal magnetic thin film may be a single layer film or a multilayer film of these.

Further, the adhesion is improved between the non-magnetic support and the metal magnetic thin film, or between the layers in the case of a multilayer film,
In addition, an underlayer or an intermediate layer may be provided to control the coercive force. Further, for example, the vicinity of the surface of the magnetic layer may be an oxide to improve the corrosion resistance. It is also possible to use the thin film forming apparatus of the present invention for forming the metal magnetic thin film, the underlayer and the intermediate layer.

Of course, the structure of the magnetic recording medium manufactured by the thin film forming apparatus of the present invention is not limited to this. For example, a back coat layer may be formed if necessary, or a magnetic recording medium may be formed on a non-magnetic support. Forming a coating layer, lubricant,
There is no problem in forming a layer such as an anticorrosive agent. In this case, as the material contained in the non-magnetic pigment, the resin binder or the lubricant, and the rust preventive agent layer contained in the back coat layer, any conventionally known materials can be used.

Further, by applying the thin film forming apparatus of the present invention,
Other metal thin films can be formed, for example, Au, Cr, Ti, Cu, Mo, Mn, Bi, A on the substrate.
It may be used for forming a thin film of a metal such as g or Pt or an alloy thereof. The thin film forming apparatus according to the present invention,
It is applicable as a sputtering apparatus using a magnetron sputtering method, a facing target method, or the like, but a magnetron sputtering apparatus in which a magnet is arranged below the target is particularly preferable. In this apparatus, the leakage magnetic field from the magnet traps the electrons and sustains the discharge, so that the target can be efficiently sputtered and the deposition rate is improved. It should be noted that an auxiliary magnet may be further arranged around the target of the above apparatus to improve the bias of the magnetic field distribution, whereby the target can be uniformly sputtered and the yield of the target is improved. You can

Further, the present invention can be opposed plasma CVD
Method, plasma irradiation CVD method, ECR plasma CVD method,
By applying it to a CVD device using a torch-type plasma CVD method or the like, it is possible to prevent the thin film material from dropping onto the counter electrode and prevent the thin film material from dropping from the gas introduction tube from affecting discharge. You can also do it.

[0018]

When the present invention is applied and the thin film formation surface of the substrate and the target sputtering surface opposite thereto are oriented in the vertical direction, the cathode electrode surface is oriented in the vertical direction, so that it falls from above the cathode electrode. The probability that the incoming thin film material will contact the cathode electrode is very low. Further, since the thin film material flying out from the target is in the horizontal direction, the thin film material not adhered to the substrate is less likely to be deposited above the cathode electrode. This suppresses the thin film material from falling onto the cathode electrode and suppresses abnormal discharge.

By the way, in the space between the target and the substrate, that is, in the space where the gas is ionized by the discharge (hereinafter referred to as the discharge space), the collision between the ions and the impurities affects the discharge state, The fall of the thin film material into this space also causes abnormal discharge. Therefore, providing the gas introduction tube below and behind the cathode mask as in the present invention prevents the thin film material attached to the gas introduction tube from dropping into the discharge space, and further suppresses abnormal discharge. Then, if the abnormal discharge can be suppressed, it becomes possible to form a thin film with a uniform film thickness and film quality.

Therefore, when the thin film forming apparatus according to the present invention is applied to the formation of the protective film on the magnetic tape, even if the protective film is continuously formed on the running flexible support for a long time, The film thickness and film quality of the protective film can be kept uniform. Therefore, it becomes possible to manufacture a magnetic tape having excellent abrasion resistance with a high yield.

[0021]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples. Here, a device to which a magnetron sputtering method is applied is used as a thin film forming device, and a protective film is formed on a so-called vapor deposition tape. Example 1 FIG. 1 shows a structural example of a thin film forming apparatus. In this apparatus, a traveling system for traveling the flexible support 5 in the vacuum chamber 2 having the exhaust ports 1a and 1b, and the flexible support 5 are provided.
And a film forming system for forming a thin film.

The traveling system is provided with a feed roll 3 which rotates at a constant speed in the direction of arrow a in the figure and a winding roll 4 which also rotates at a constant speed in the direction of arrow b in the figure. A tape-shaped flexible support 5 is sequentially run from the roll 3 to the winding roll 4. A cylindrical can 6 having a diameter larger than that of each of the rolls 3 and 4 is provided in the middle of the flexible support 5 running from the feed roll 3 to the take-up roll 4 side. The cylindrical can 6 is provided so as to pull out the flexible support 5 to the front side in the figure, and is configured to rotate at a constant speed in a direction indicated by an arrow c in the figure. The feed roll 3, the winding roll 4, and the cylindrical can 6 are cylindrical bodies each having a length substantially the same as the width of the flexible support body 5, and the long axis direction of these is the same as the vertical direction. It is done like this. Further, a cooling device (not shown) is provided inside the cylindrical can 6 so that deformation of the flexible support 5 due to a temperature rise can be suppressed.

Therefore, the flexible support 5 is sequentially fed out from the feed roll 3 in a state where its main surface is parallel to the vertical direction, and further travels along the peripheral surface of the cylindrical can 6 for winding. It is designed to be wound around the take-up roll 4. Although the cylindrical can 6 is cooled in this embodiment, it may be appropriately heated to increase the adhesive strength between the flexible support and the thin film. For the same purpose, a bombarding process may be performed in advance before film formation.

On the other hand, the film forming system is composed of a cathode unit 9 provided so as to face the peripheral surface of the cylindrical can 6, a target 10 made of a thin film raw material and a gas introducing pipe 16 arranged on the surface. It The cathode unit 9 is
As shown in the cross section of FIG. 2, a backing plate 1 connected to a power source (not shown) and serving as a cathode electrode.
1, a magnet 12 and a magnet 13 arranged on the back side of the backing plate 11, the magnet 1
It comprises a cathode case 14 accommodating 2 and 13.

The surface of the backing plate 11 has a larger area than that of the target 10. However, the cathode mask 15 has a size other than the range in which the target 10 is arranged.
Coated with The cathode mask 15 surrounds the periphery of the target 10 and the backing plate 1
1 is masked. The outer peripheral edge of the backing plate 1 is adhered to the cathode case 14 and its lower surface is
1 without touching 1 and the side surface of the target 10
It is fixed without touching.

A cooling pipe (not shown) for supplying and discharging cooling water is connected to the cathode unit 9, and the backing plate 11 and the target 10 adhered thereto are heated by circulating the cooling water. It is designed to prevent Also, the magnets 12, 13
Is arranged so that the magnet 13 surrounds the magnet 12 located in the center, and a leakage magnetic field is generated between the magnet 12 and the magnet 13.

The gas introducing pipe 16 is located below the cathode unit 9 and is located on the main surface 1 of the cathode mask 15.
It is provided behind 5a. In addition, gas introduction pipe 1
The gas inlet 16a in 6 is provided in parallel with the width direction of the cathode unit 9 and has a length approximately the same as the width of the cathode unit 9. In addition, here, the gas introduction port 16a is opened in the direction perpendicular to the sputtered surface 10a of the target 10, and the target 1
The gas can be supplied to the space between 0 and the flexible support 5 facing it.

In the thin film forming apparatus having the above-mentioned structure, power is supplied to the backing plate 11 while the vacuum chamber 2 is kept at a certain degree of vacuum, and the gas inlet 16
When the gas is supplied from a, a discharge is generated between the cylindrical can 6 and the gas to be ionized, and the target 10 is attacked, so that the thin film material is deposited on the traveling flexible support 5 surface. The leakage magnetic field generated by the magnets 12 and 13 traps electrons to sustain discharge and enables efficient sputtering. Also, the backing plate 11
The area in which the target 10 is not provided is shielded from ion attack by the cathode mask 15.

Then, the thin film forming apparatus as described above was applied to the formation of a protective film of a magnetic recording medium, and a magnetic tape was prepared as follows. First, a Co—Ni-based metal magnetic thin film was deposited on the undercoated non-magnetic support using a general continuous winding type oblique vapor deposition apparatus. The base, undercoat and vapor deposition conditions used are as follows.

Non-magnetic support conditions Base: Polyethylene terephthalate 10 μm thickness 150 mm width Undercoat: Water-soluble latex mainly composed of acrylic ester is applied Protrusion density: about 10 million pieces / mm ² Deposition condition Ingot: Co80-Ni20 (numbers are for each Weight ratio of metal) Incident angle: 45 to 90 ° Tape speed: 0.17 m / sec Magnetic layer thickness: 0.2 μm Vacuum degree: 7 × 10 ^-2 Pa Next, a protective film is formed by the thin film forming apparatus described above. Formed. The sputtering conditions are shown below.

Sputtering conditions Method: DC magnetron sputtering method Target: Carbon, size 150 mm × 1
50 mm Gas used: Argon Vacuum degree: 0.6 Pa Tape speed: 0.1 m / sec Protective film thickness: 15 nm Input power: 10 w / cm ² Furthermore, backcoat and topcoat are applied according to the following conditions to give a predetermined tape width. It was cut into a magnetic tape.

Backcoat: A mixture of carbon and urethane binder was applied to a thickness of 0.6 μm. Topcoat: Perfluoropolyether was applied Slit width: 8 mm width Comparative Example 1 Here, as compared with Example 1, gas was used. A thin film forming apparatus in which the introduction tube 16 was provided in the front was used.

Specifically, as shown in FIG. 3 showing the cathode unit 9 and the gas introducing pipe 16, the gas introducing pipe 16 is located below the cathode unit 9 and in front of the main surface 15a of the cathode mask 15. The gas inlet 16a is provided and is opened upward. Other than this, the configuration is similar to that of the first embodiment. Then, using the thin film forming apparatus as described above, a protective film was formed in the same manner as in Example 1 to produce a magnetic tape. Comparative Example 2 Here, a thin film forming apparatus in which the gas introduction pipe 16 was provided above the cathode unit 9 was used.

Specifically, as shown in FIG. 4 showing the cathode unit 9 and the gas introducing pipe 16, the gas introducing pipe 16 is located above the cathode unit 9 and in front of the main surface 15a of the cathode mask 15. The gas inlet 16a is provided and is opened downward. Other than this, the configuration is similar to that of the first embodiment. Then, using the thin film forming apparatus as described above, a protective film was formed in the same manner as in Example 1 to produce a magnetic tape. Comparative Example 3 Here, a conventional thin film forming apparatus was used.

The specific structure is as described above,
As shown in FIG. 5, the feed roll 3, the take-up roll 4, and the cylindrical can 6 are arranged such that their major axis directions are aligned in the horizontal direction, and the cathode unit 9 is disposed below the cylindrical can 6. The sputtered surface 10a of the target 10 faces the peripheral surface and faces upward. Further, as shown in FIG. 6, the gas introduction pipe 16 is provided on the side of the cathode unit 9, and a gas introduction port 16a having a length substantially the same as the major axis of the cathode unit 9 is opened toward the side. Except for this, the configuration is substantially the same as that of the first embodiment.

Then, using the thin film forming apparatus as described above, a protective film was formed in the same manner as in Example 1 to produce a magnetic tape. Evaluation of characteristics Using the thin film forming apparatus having different configurations as described above, the protective film was continuously formed for 10 hours, and the number of occurrences of abnormal discharge was examined. The number of abnormal discharges was the number of times the voltage or current per minute fluctuated by 20% or more. Also, a magnetic tape manufactured by using each thin film forming apparatus is mounted on a recording / reproducing apparatus such as an EV-S900 manufactured by Sony Corp., and a signal of 50% white is recorded and -16 dB / min per minute.
The number of dropouts of 0 μsec or more was counted. Table 1 shows the results.

[0037]

[Table 1]

From Table 1, when the thin film forming apparatus of Example 1 is used, the number of occurrences of abnormal discharge is the smallest, and the dropout in the magnetic tape having the protective film formed by the thin film forming apparatus is the smallest. I understand. Further, when comparing the respective comparative examples, Comparative example 1, Comparative example 2,
It can be seen that the number of abnormal discharges increased in the order of Comparative Example 3, and the dropout in the magnetic tape on which the protective film was formed using each thin film forming apparatus also deteriorated in the above order.

As a result, when the thin film forming surface of the substrate and the sputtered surface 10a of the target 10 facing the thin film forming surface are oriented in the vertical direction, the gas introducing pipe 16 is further arranged below the cathode unit 9. It has been found that it is more preferable that the gas introduction pipe 16 is arranged rearward of the main surface 15a of the cathode mask 15.

The example in which the thin film forming apparatus according to the present invention is applied to the formation of the protective film of the magnetic recording medium has been described above.
The present invention is not limited to the above-described embodiments, and various modifications and changes can be made without departing from the gist of the present invention. For example, in the thin film forming apparatus, guide rolls are provided between the feed roll 3 and the cylindrical can 6 and between the cylindrical can 6 and the winding roll 4, respectively, and along the cylindrical can 6. Flexible support 5 running
You may make it apply predetermined tension to. Also,
The material of the target, the arrangement of magnets, etc. can be changed, and the thin film formed by the thin film forming apparatus is not limited to the protective film, and may be a metal magnetic thin film or a conductive metal thin film. Also, when applied to the formation of a protective film in a magnetic recording medium, the material of the protective film and the film forming conditions can be changed as appropriate, and the forming conditions of the magnetic thin film, the back coat layer, the top coat layer, etc. can be changed conventionally. Any known method can be applied.

[0041]

As is apparent from the above description, in the thin film forming apparatus of the present invention, it is difficult for the thin film material to fall onto the cathode electrode, and the thin film is formed in the space between the target and the substrate. Since the material can be prevented from dropping, abnormal discharge can be suppressed and a thin film having a uniform film thickness and film quality can be formed.

Therefore, when the thin film forming apparatus according to the present invention is applied to the formation of the protective film on the magnetic tape, even if the protective film is continuously formed on the running flexible support for a long time, The film thickness and film quality of the protective film can be kept uniform, and a magnetic tape having excellent wear resistance can be manufactured with a high yield.

[Brief description of drawings]

FIG. 1 is a schematic view showing a configuration example of a thin film forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view schematically showing a cathode unit and a gas introduction pipe in the thin film forming apparatus of the embodiment.

FIG. 3 is a cross-sectional view schematically showing a cathode unit and a gas introduction pipe in a thin film forming apparatus of a comparative example.

FIG. 4 is a cross-sectional view schematically showing a cathode unit and a gas introduction pipe in a thin film forming apparatus of another comparative example.

FIG. 5 is a schematic view showing a configuration example of a conventional thin film forming apparatus.

FIG. 6 is a cross-sectional view schematically showing a cathode unit and a gas introduction pipe in a conventional thin film forming apparatus.

[Explanation of symbols]

 1 Exhaust Port 2 Vacuum Chamber 3 Feed Roll 4 Winding Roll 5 Flexible Support 6 Cylindrical Can 9 Cathode Unit 10 Target 11 Backing Plate 12, 13 Magnet 14 Cathode Case 15 Cathode Mask 16 Gas Inlet Pipe

Claims (3)

[Claims] 1. A target disposed on a cathode electrode is sputtered while introducing gas from a gas introducing pipe,
In a thin film forming apparatus for forming a thin film on a surface of a substrate facing the target, a thin film forming surface of the substrate and a sputtering target surface of the target facing the substrate are in a vertical direction, and the gas introduction tube is a cathode electrode. A thin film forming apparatus characterized in that the thin film forming apparatus is provided below and behind a cathode mask covering a region of the surface where the target is not provided. 2. The thin film forming apparatus according to claim 1, wherein the base is a flexible support in which a metal magnetic thin film is formed on a long film. 3. The thin film forming apparatus according to claim 2, wherein the thin film to be formed is a protective film made of carbon.