JPH0820865A - Thin film forming equipment - Google Patents

Abstract

(57) [Summary] [Structure] Target 10 on backing plate 11
In a thin film forming apparatus for forming a thin film on the surface of a flexible support that runs above the target 10 by sputtering, the range of the surface of the backing plate 11 where the target 10 is not disposed is a cathode mask. The upper surface 15a of the cathode mask 15 is masked by 15, and is made lower than the surface 10a of the target 10. The upper surface of the end portion of the cathode mask 15 which is close to the target 10 may be obliquely cut. [Effect] It is difficult for the thin film material to fall onto the cathode electrode, and the occurrence of abnormal discharge can be suppressed. Therefore, when the thin film forming apparatus of the present invention is applied to the formation of a protective film on a magnetic tape, the film thickness and film quality of the protective film can be kept uniform, and a magnetic tape excellent in abrasion resistance can be manufactured with high yield.

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. 1 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 partitioned by a partition plate, and the cathode unit 109 is provided below the cylindrical can 6, and the raw material of the thin film disposed on the surface of the cathode unit 109. The target 10 and the gas introduction pipe. The cathode unit 109 is
As shown in the cross section in FIG. 5, 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 below the backing plate 11, and a cathode case 14 for housing them. Further, a target 10 having a smaller area than this is adhered onto the backing plate 11, and a region where the target 10 is not arranged is covered with a cathode mask 115 to protect it from ion attack.

The cathode mask 115 has its outer peripheral edge portion bonded to the cathode case 14, and its lower surface is fixed without contact with the backing plate 11 and its side surface without contact with the target 10. In addition, at the end near the target 10,
Its cross-sectional shape is substantially rectangular, and its upper surface 115
The height a is substantially the same as the surface of the target 10.

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 cylindrical can 6 and the gas supplied from the gas introduction tube is ionized and attacks the target 10, so that the thin film material is deposited on the surface of the flexible support 5.

[0008]

By the way, the thin film material 116 blown out from the target 10 adheres to the inner wall of the vacuum chamber 2, the partition plate, the cathode unit 109, etc. in addition to the flexible support 5. However, as shown in FIG. 5, the thin film material 116 is most likely to be deposited on the end portion of the cathode mask 115 which is close to the target 10. In particular, in the vicinity of the ridgeline formed by the upper surface 115a of the cathode mask 115 and the side surface facing the target 10, the thin film material 116 deposited in this manner is used as the backing plate 11.
Since it swells upward, if it is deposited for a long time, it will fall onto the backing plate 11. Backing plate 11 of this thin film material 116
The falling into the ground causes abnormal discharge.

When the abnormal discharge occurs, problems such as making the thickness of the thin film formed on the flexible support 5 non-uniform and causing an abnormality in the film quality will occur. Therefore, the present invention has been proposed in view of such conventional circumstances, and an object thereof is to provide a thin film forming apparatus capable of forming a thin film with a uniform film thickness and film quality by suppressing abnormal discharge. .

[0010]

A thin film forming apparatus according to the present invention has been proposed to achieve the above-mentioned object, and a target provided on a cathode electrode is sputtered to produce a thin film of the target. In a thin film forming apparatus for forming a thin film on the surface of a substrate facing upward, a range of the cathode electrode surface where the target is not disposed is masked by a cathode mask, and the upper surface of the cathode mask is the target surface. Is lower than that.

As described above, the thin film material punched out from the target does not easily adhere to the cathode mask which is lower than the target surface. In addition, in order to sufficiently suppress the deposition of the thin film, it is preferable that the upper surface of the cathode mask is set back from the target surface by 1 mm or more.
In order to prevent the thin film material from falling onto the cathode electrode even if the thin film material is deposited on the cathode mask, the end portion of the cathode mask in the vicinity of the target is preferably formed by obliquely cutting the upper surface. is there. Specifically, in the vicinity of the ridge formed by the upper surface of the cathode mask and the side surface facing the target, both the upper surface and the side surface are notched by 2 mm or more from the ridge line, so-called C chamfering is chamfered at C2 or more. It is preferable.

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. Any conventionally known material can be used as the material of the protective film, such as CrO ₂ , Al ₂ O ₃ , BN, Co oxide, MgO, SiO ₂ , Si ₃ O ₄ , SiN _x , Si.
_{C, SiN x -SiO 2, ZrO} 2, TiO 2, TiC
Etc., 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 can be applied as a sputtering apparatus using a magnetron sputtering method or a facing target method. In particular, it is preferable to use a magnetron sputtering device in which a magnet is arranged below the target. Since the leakage magnetic field from the magnet traps electrons and sustains discharge, it is possible to efficiently sputter the target. The film forming speed 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

[0017]

In the thin film forming apparatus according to the present invention, it is difficult for the thin film material to adhere to the cathode mask. This is because the thin film material struck out from the target jumps out upward, so that it is difficult to adhere to the cathode mask provided below the target surface. And
If the amount of thin film material deposited on the cathode mask decreases,
It does not easily fall onto the cathode electrode.

When the end portion of the cathode mask near the target has a substantially rectangular cross section, the thin film material deposited near the ridgeline formed by the upper surface of the cathode mask and the side surface facing the target is most likely to fall off. If the structure is cut out, the thin film material will not squeeze and deposit on the cathode electrode, and will not easily fall off.
That is, by notching the end portion of the cathode mask, it is possible to prevent the thin film material from dropping onto the cathode electrode and suppress abnormal discharge. When the abnormal discharge can be suppressed, a thin film can be formed 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 a protective film on a 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 this protective film can be kept uniform. Therefore, it becomes possible to manufacture a magnetic tape having excellent abrasion resistance with a high yield.

[0020]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples. Here, a magnetron sputtering device was used as a thin film forming device to form a protective film on a so-called vapor deposition tape. Example 1 In this example, a thin film forming apparatus was used in which the upper surface of the cathode mask was 1 mm lower than the target surface.

FIG. 1 shows an example of the structure of a thin film forming apparatus. In this apparatus, a traveling system for traveling the flexible support 5 in a vacuum chamber 2 having exhaust ports 1a and 1b, and a film forming system for forming a thin film on the flexible support 5 And are provided. The traveling system is provided with a feed roll 3 that rotates at a constant speed in the direction of arrow a in the figure and a winding roll 4 that also rotates at a constant speed in the direction of arrow b in the figure. The tape-shaped flexible support 5 is attached to the winding roll 4.
Are designed to run sequentially.

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 travel of the flexible support 5 from the feed roll 3 to the winding roll 4 side. ing. The cylindrical can 6 is provided so as to pull out the flexible support 5 downward in the figure, and is indicated by an arrow c in the figure.
It is configured to rotate at a constant speed in the direction indicated by. The feed roll 3, the take-up roll 4, and the cylindrical can 6 are cylindrical bodies each having a length substantially the same as the width of the flexible support 5, and the cylindrical can 6 is internally illustrated. A cooling device that does not operate is provided to suppress deformation of the flexible support 5 due to a temperature rise.

Therefore, the flexible support 5 is sequentially fed from the feed roll 3, and the cylindrical can 6 is further fed.
It travels along the peripheral surface of and is wound up by the winding roll 4. Guide rolls 7 and 8 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 run along the cylindrical can 6. Flexible support 5
A predetermined tension is applied to the flexible support 5 so that the flexible support 5 runs smoothly.

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 provided on the lower side of the vacuum chamber 2 partitioned by a partition plate, and is provided below the cylindrical can 6, the cathode unit 9, a target 10 made of a raw material of a thin film disposed on the surface of the cathode unit 9. It is composed of a gas inlet pipe. As shown in the cross section of FIG. 2, the cathode unit 9 includes a backing plate 11 connected to a power source (not shown) and serving as a cathode electrode, a magnet 12 disposed below the backing plate 11, and a magnet. 13, a cathode case 14 that houses the magnets 12 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 As shown in FIG. 3 which is a top view of the cathode unit 9, the cathode mask 15
Surrounds the periphery of the target 10 and masks the backing plate 11. The outer peripheral edge is adhered to the cathode case 14, and its lower surface is fixed without contact with the backing plate 11 and its side surface without contact with the target 10. In addition, the end portion near the target 10 has a substantially rectangular cross-sectional shape, and the upper surface 15a has an upper surface 15a.
Is provided so as to be lower than the surface 10a. In this embodiment, the upper surface 1 of the cathode mask 15
The difference d between 5a and the surface 10a of the target 10 was set to 1 mm.

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
Are arranged so that the magnet 13 surrounds the magnet 12, and the magnet 12 located in the center shows the S pole in the upper portion 12A thereof. It is supposed to indicate a pole.

Therefore, in the thin film forming apparatus described above, when the vacuum chamber 2 is kept at a certain degree of vacuum, power is supplied to the backing plate 11 and gas is supplied from the gas introducing pipe, the cylindrical can 6 is formed. A discharge is generated in the meantime to ionize the gas and attack the target 10 to deposit the thin film material on the surface of the running flexible support 5. The leakage magnetic field generated by 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.

The apparatus having the above-mentioned structure was applied to the formation of the protective film of the magnetic recording medium, and the magnetic tape was prepared as follows. First, by using a general continuous winding type oblique vapor deposition apparatus on a non-magnetic support having an undercoat, C
An o-Ni-based metal magnetic thin film was applied. 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 containing acrylic ester as a main component Projection density approx. 10 million pieces / mm ² Vapor deposition conditions Ingot: Co80-Ni20 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 Example 2 In this example, the cathode to the surface 10a of the target 10 was used. The thin film forming apparatus was used in which the position of the upper surface 15a of the mask 15 was made lower than in the first embodiment.

Specifically, the upper surface 1 of the cathode mask 15
A thin film forming apparatus having the same configuration as in Example 1 was used except that the difference d between 5a and the surface 10a of the target 10 was 3 mm. Then, a protective film was formed by this, and a magnetic tape was produced in the same manner as in Example 1. Example 3 In this example, the difference d between the upper surface 15a of the cathode mask 15 and the surface 10a of the target 10 is the same as that in Example 2, and further, at the end of the cathode mask 15 close to the target 10, the upper surface is A thin film forming apparatus in which 15a was obliquely cut was used.

Specifically, as shown in FIG. 4, the upper surface 15a of the cathode mask 15 and the surface 1 of the target 10 are
The difference d from 0a is 3 mm, and the vicinity of the ridge formed by the upper surface 15a of the cathode mask 15 and the side surface 15b facing the target 10 is cut out by 2 mm from the ridge line for both the upper surface 15a and the side surface 15b, so-called C2. The cross-sectional shape is chamfered. And this
A slope 15c is formed at the end of the cathode mask 15.

A magnetic tape was manufactured in the same manner as in Example 1 except that the thin film forming apparatus having the same structure as in Example 1 was used for forming the protective film. Example 4 In this example, a thin film forming apparatus was used in which the notch at the end of the cathode mask 15 close to the target 10 was made larger than that in Example 3.

Specifically, the upper surface 1 of the cathode mask 15
5a and the surface 10a of the target 10 have a difference d of 3 mm, and the upper surface 15a of the cathode mask 15 and the target 1
The vicinity of the ridge formed by 0 and the side surface 15b facing each other is the upper surface 15
Both a and the side surface 15b have a so-called C5 chamfered cross-sectional shape that is cut out by 5 mm from the ridge line. A magnetic tape was produced in the same manner as in Example 1 except that the thin film forming apparatus having the same configuration as in Example 1 was used for forming the protective film. Comparative Example 1 In this comparative example, the surface 10a of the target 10 and the upper surface 115a of the cathode mask 115 have the same height, and further, a thin film forming apparatus in which a notch is not provided at an end portion of the cathode mask 115 close to the target 10. Was used.

Specifically, as shown in FIG. 5, the upper surface 115a of the cathode mask 115 is at the same height as the surface 10a of the target 10, that is, the difference between the upper surface 115a of the cathode mask 115 and the surface 10a of the target 10. d is 0
It was set to mm. Furthermore, no cutout was provided in the end portion close to the target 10, and the cross-sectional shape was substantially rectangular. A magnetic tape was produced in the same manner as in Example 1 except that the thin film forming apparatus having the same configuration as in Example 1 was used for forming the protective film. Evaluation of characteristics The thickness of the protective film material adhering to the cathode masks 15 and 115 is measured when the protective film is continuously formed for 10 hours using the thin film forming apparatus having different configurations as described above. In addition, the number of occurrences of abnormal discharge was examined. The number of occurrences of the abnormal discharge was the number of times that the voltage or current per minute fluctuated by 20% or more. In addition, a magnetic tape manufactured by using each thin film forming apparatus is manufactured by Sony Corporation, EV-S.
The recording / reproducing apparatus No. 900 was used to record a signal of 50% white, and the number of dropouts of -16 dB per minute for 10 μsec or more was counted. Table 1 shows the results.

[0037]

[Table 1]

In Table 1, the numerical value indicated by "d" is the difference between the upper surface 15a of the cathode mask 15 and the surface 10a of the target 10 in each thin film forming apparatus,
In the column of "presence or absence of notch", whether or not the upper surface 15a is notched at the end of the cathode mask 15 and, if a notch is provided, the type of chamfering is described. Further, the numerical value indicated by “thickness of deposit” is the thickness of the protective film material attached to the cathode masks 15, 115.

From Table 1, as compared with the film formation using the thin film forming apparatus of Comparative Example 1, the film forming using the thin film forming apparatus of Examples 1 to 4 shows that the protective film adhered to the cathode mask 15 It can be seen that the thickness of the material is reduced and the number of abnormal discharges is significantly reduced. Also, it can be seen that the number of dropouts in the magnetic tape manufactured by using each thin film forming apparatus is significantly reduced. It should be noted that when the respective examples are compared with each other, good results are obtained as the difference d between the upper surface 15a of the cathode mask 15 and the surface 10a of the target 10 is larger and the notch at the end of the cathode mask 15 is larger. I understand.

As a result, the upper surface 15 of the cathode mask 15 is
a is set to be lower than the surface 10a of the target 10, and further, by using a thin film forming apparatus in which a notch is provided at an end portion of the cathode mask 15 close to the target 10, abnormal discharge is reduced and protection excellent in film quality is performed. It was found that a film can be formed. Although 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 embodiment, and various modifications and changes can be made. For example, in a thin film forming apparatus, it is possible to change the material of the target, the arrangement of magnets, etc., and the thin film formed by the thin film forming apparatus is not limited to the protective film, but may be a metal magnetic thin film or a conductive metal thin film. May be.

[0041]

As is clear from the above description, in the thin film forming apparatus of the present invention, since the thin film material is unlikely to drop on the cathode electrode, the occurrence of abnormal discharge is suppressed and a uniform film thickness is obtained. And a thin film having a 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 traveling flexible support for a long time, the protective film is formed. The film thickness and film quality can be kept uniform, and it becomes possible to manufacture a magnetic tape having excellent wear resistance with high yield.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a thin film forming apparatus.

FIG. 2 is a cross-sectional view schematically showing a configuration example of a cathode unit in the thin film forming apparatus according to the present invention.

FIG. 3 is a plan view showing an upper surface of the cathode unit shown in FIG.

FIG. 4 is an enlarged cross-sectional view schematically showing another configuration example of the cathode unit in the thin film forming apparatus according to the present invention.

FIG. 5 is a sectional view schematically showing a cathode unit in a conventional thin film forming apparatus.

[Explanation of symbols]

 1a, b Exhaust port 2 Vacuum chamber 3 Feed roll 4 Winding roll 5 Flexible support 6 Cylindrical can 7,8 Guide roll 9 Cathode unit 10 Target 11 Backing plate 12,13 Magnet 14 Cathode case 15 Cathode mask

Claims (4)

[Claims] 1. A thin film forming apparatus for forming a thin film on a surface of a substrate facing above the target by sputtering a target arranged on the cathode electrode, wherein the target is arranged on the surface of the cathode electrode. A thin film forming apparatus, wherein an area not provided is masked by a cathode mask, and an upper surface of the cathode mask is lower than a surface of the target. 2. The thin film forming apparatus according to claim 1, wherein an upper surface of an end portion of the cathode mask adjacent to the target is obliquely cut out. 3. 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. 4. The thin film forming apparatus according to claim 3, wherein the thin film to be formed is a protective film made of carbon.