JPH06306602A - Production of thin film - Google Patents

Abstract

PURPOSE:To increase the rate of film formation without supplying high electric power to a cathode unit and to produce a thin film with high productivity. CONSTITUTION:When a thin film is formed by sputtering, a pair of auxiliary electrodes 17 are arranged near a cathode unit 9 and sputtering is carried out while allowing the electrodes 17 to discharge electricity or sputtering is carried out, while feeding electrons from an electron beam gun to a target material 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film manufacturing method for forming a thin film by a sputtering method.

[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 in particular, the vapor deposition method has an advantage that high-speed film formation is possible by using an electron gun (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. It is known that this sputtering method improves durability and corrosion resistance of the magnetic recording medium when applied to, for example, formation of a protective film on a magnetic recording medium of a metal magnetic thin film type.

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.

For example, in the above magnetron sputtering method, a magnet is arranged below the target and electrons are trapped by the leakage magnetic field to sustain discharge (perform cyclotron motion). The target can be efficiently sputtered, and the film formation speed becomes relatively high. The film forming rate can be improved by increasing the number of targets arranged in the vacuum apparatus, increasing the amount of electric power supplied to each target, and the like.

[0006]

However, since the number of targets that can be arranged in a limited space is limited, it is difficult to increase the film formation rate by increasing the number of targets, and the supply to the targets is difficult. When the amount of applied electric power is increased, the heat generated during sputtering increases, so that the bonding agent such as solder that adheres the target and the backing plate begins to melt, causing a problem such as short-circuiting the electrodes.

As described above, it is the actual situation that a sufficient film formation rate has not been obtained even by the magnetron sputtering method.

Therefore, the present invention has been proposed in view of the above conventional circumstances, and an object of the present invention is to provide a method for producing a thin film which improves the film forming rate and is excellent in productivity.

[0009]

The present invention has been proposed in order to achieve the above object, and is a method for producing a thin film by forming a thin film by sputtering a target placed on a cathode unit. In the above, the electron supply means or the discharge electrode is arranged in the vicinity of the cathode unit, and the film formation is performed while supplementarily supplying electrons to the cathode unit or while discharging.

The electron supply means is an electron gun (EB
Cancer).

In the method for producing a thin film of the present invention, for example, a metal thin film type magnetic tape (so-called vapor deposition tape) having a metal magnetic thin film, an abrasion resistant thin film (protective film) and the like provided on a non-magnetic support is produced. It is suitable for use.

As a material for the metal magnetic thin film, any material can be used as long as it is used for a usual vapor deposition tape. For example, ferromagnetic metal materials such as Fe, Co and Ni, Fe-Co, Co-Ni, Fe-Co-N
i, Fe-Cu, Co-Cu, Co-Au, Co-P
t, Mn-Bi, Mn-Al, Fe-Cr, Co-C
r, Ni-Cr, Fe-Co-Cr, Co-Ni-C
Examples include ferromagnetic alloy materials such as r and Fe—Co—Ni—Cr.

The metal magnetic thin film may be a single layer film or a multilayer film of these. Furthermore, between the flexible support and the metal magnetic thin film, or in the case of a multilayer film,
An underlayer or an intermediate layer may be provided in order to improve the adhesive force between the layers and 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 apparatus of the present invention for forming the underlayer and the intermediate layer.

When a wear resistant thin film (protective film) is formed by applying the present invention, any material can be used as long as it is generally used as a wear resistant thin film material. For example, carbon, Cr
O ₂ , Al ₂ O ₃ , BN, Co oxide, MgO, SiO
_{2, Si 3 O 4, SiN} x, SiC, SiN x -SiO
₂ , ZrO ₂ , TiO ₂ , TiC and the like. Further, the protective film may be a single layer film of these, a multilayer film or a composite film with a metal.

Of course, the structure of the magnetic tape produced by the manufacturing method of the present invention is not limited to this, and for example, a back coat layer may be formed if necessary,
There is no problem in forming an undercoat layer or forming a layer of a lubricant, a rust preventive agent or the like on the flexible support. 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.

By applying the manufacturing method of the present invention, other metal thin films can be formed. For example, Au, Cr, Ti, Cu, Mo, Mn, Bi, Ag,
It may be used to form a thin film of a metal such as Pt or an alloy thereof.

[0017]

When an electron supply means such as an EB gun is arranged near the cathode unit so that a large number of electrons are present on the surface of the cathode unit, the sputtering gas easily attacks the target and the film formation rate is improved. Can be made. Further, similarly, by disposing a discharge electrode in the vicinity of the cathode unit and performing sputtering while discharging, efficient film formation can be performed.

As a result, the same effect as increasing the amount of electric power supplied to the cathode unit can be obtained, but a large amount of heat as in the case of directly supplying large electric power to the cathode unit is not generated. Therefore, the bonding agent that bonds the target and the backing plate does not start to melt.

[0019]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

Experiment 1 First, the present invention was applied to form a Cr film on a substrate. The configuration of the applied apparatus used for thin film formation will be described below.

As shown in FIG. 1, in this thin film manufacturing apparatus, exhaust ports 1a, 1 are provided at the top and bottom, respectively.
A feed roll 3 that rotates at a constant speed in the direction of an arrow a in FIG.
Similarly, a winding roll 4 that rotates at a constant speed in the direction of the arrow b in the figure is provided, and the tape-shaped flexible support 5 is sequentially run from these feed rolls 3 to the winding roll 4. Has been done.

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 each a cylindrical body 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, further runs along the peripheral surface of the cylindrical can 6, and is wound up by the winding roll 4. There is. In addition, between the feed roll 3 and the cylindrical can 6, and between the cylindrical can 6 and the take-up roll 4.
Guide rolls 7 and 8 are respectively provided between the flexible can 5 and the cylindrical can 6, and a predetermined tension is applied to the flexible carrier 5 traveling along the cylindrical can 6 so that the flexible carrier 5 smoothly travels. It is done like this.

Although the cylindrical can 6 is cooled in this embodiment, it may be appropriately heated in order to increase the adhesive strength between the flexible support and the metal thin film. For the same purpose, a bombarding process may be performed in advance before film formation.

Further, the cylindrical can 6 is provided in the vacuum chamber.
There is a cathode unit 9 below, and a target material 10 which is a thin film material is adhered to the surface of the cathode unit 9. As shown in the cross section of FIG. 2, the cathode unit 9 includes a backing plate 11 which is connected to a power source (not shown) and serves as a negative electrode, a magnet 12 arranged below the backing plate 11, and It comprises a magnet 13 and a cathode case 14 that houses the magnets 12, 13.

A target material 10 having a smaller area than this is adhered on the backing plate 11, and a supply port of a gas introduction pipe 18 for sputter gas is provided so as to face the target material 10 (see FIG. 1). ). Then, in the backing plate 11, the target material 1
A cathode cover 15 is provided to cover a portion where the target material 10 is not arranged so that sputtered ions do not attack a portion not covered with 0. Note that arrow c
Indicates the traveling direction of the flexible support 5.

A cooling pipe 16 for supplying and discharging cooling water is connected to the cathode unit 9, and the backing plate 11 and the target material 10 adhered thereto are heated by circulating the cooling water. Are prevented.

The magnets 12 and 13 are arranged so that the magnet 13 surrounds the magnet 12, for example. Then, the magnets 12 and 1 are housed in the cathode case 14 in such a state.
A magnetic field exists on the upper surface of the cathode unit 9 due to the leakage magnetic field 3 of FIG. When sputtering is performed in the presence of such a magnetic field, electrons are trapped by the leakage magnetic field to sustain discharge, so that the target material 1
0 can be efficiently sputtered.

The thin film manufacturing apparatus is characterized in that the discharge electrode 17 is arranged in the vicinity of the cathode unit 9 for the purpose of improving the efficiency of sputtering. 2 (cathode unit 9
As viewed from the side) and FIG. 3 (view of the cathode unit 9 viewed from the top), the pair of discharge electrodes 17
a and 17b are arranged laterally of the cathode unit 9 in parallel with the width direction of the flexible support 5 indicated by the arrow d.

As shown in FIG. 4, the discharge electrodes 17a and 17b are columnar electrodes composed of a discharge part 19 made of stainless steel or the like and an insulating part 20.
Cooling water circulates inside 9 to prevent heat generation. Further, a magnet 21 made of ferrite, SmCo, or the like is arranged inside the discharge portion 19, and the structure of the magnet 21 allows discharge even with a small gas supply amount.

Further, in the present embodiment, the discharge electrodes 17a and 17b having a diameter of 20 mm are arranged in parallel with a distance of 15 mm. Generally, the interval between the discharge electrodes is determined by various device conditions such as the size of the vacuum chamber 2,
Stable discharge cannot be maintained when the distance is more than about 60 mm.

The electric power applied to the discharge electrodes 17a and 17b varies depending on the distance between the electrodes, the degree of vacuum, the presence or absence of the magnet 21 inside the electrodes, and the like, but stable discharge is maintained and the sputtering efficiency is improved. In order to improve it, it is necessary to have about 300 V, 0.05 A (15 W) or more, and below this, the effect of discharge cannot be exhibited. On the contrary, if the electric power of 1000V, 1A (1kW) or more is supplied,
Since the heat generated by the discharge becomes large, the flexible support 5 running on the peripheral surface of the cylindrical can 6 may be damaged by the heat. In particular, it cannot be used for those having a metal magnetic film formed thereon.

Here, it is preferable to supply electric power of 15 W to 1 kW, and since the flexible support 5 having a width of 150 mm is used, it is 150 when converted per unit length.
The electric power is W / m to 6670 W / m.

The discharge electrodes 17a and 17b are
The cathode unit 9 is connected to a power source (which is installed outside the vacuum chamber 2 but not shown here) different from the power source for supplying the cathode unit 9 with the power, so that the cathode unit 9 is It is designed to be discharged independently.

In the thin film manufacturing apparatus as described above, the vacuum chamber 2 is maintained at a constant vacuum degree, and the discharge electrodes 17a, 1
A thin film is formed by sputtering the target material 10 on the cathode unit 9 and depositing it on the surface of the running flexible support 5 while discharging with 7b.

Using the above apparatus, a Cr film was formed on a flexible support under the following conditions to prepare a sample of Example 1.

Sputtering conditions Flexible support: Polyethylene terephthalate (thickness 10 μm, width 150 mm) Target material: Cr, size 150 mm × 150
mm Gas used: Argon Vacuum degree in apparatus: 4 × 10 ⁻³ Pa Vacuum degree during film formation: 2 Pa Thin film thickness: 0.1 μm

The discharge electrodes 17a and 17b have D
Electric power of 300V, 0.2A is supplied from the C power source, and 6 W / cm ² is applied to the backing plate 11 of the cathode unit 9.
I turned on the power. Further, the feed rate of the flexible support 5 is such that the thin film thickness is 0.1 above under the above-mentioned sputtering conditions.
It was adjusted to be μm.

In general, a bombarding process is performed in advance just before the film formation in order to improve the adhesion between the flexible support 5 and the metal or the like to be formed. The discharge electrode 17 described above also has the effect of this bombarding process. This bombardment treatment was not carried out in this embodiment because it had a combination.

Further, for comparison, the above-mentioned discharge electrode 1
A sample of Comparative Example 1 was prepared in which film formation was performed in the same manner as in Example 1 except that an apparatus in which 7 was not installed was used. The sample of Comparative Example 1 was also not subjected to the bombarding treatment during film formation. In addition, as Comparative Example 2, after performing the bombarding process, a sample in which film formation was performed by an apparatus having no discharge electrode 17 was also prepared as in Comparative Example 1.

With respect to each of the samples prepared as described above, the adhesiveness of the formed thin film was examined. The adhesiveness was evaluated as x when scratched or peeled with a pencil tip sharply scraped on the surface of the thin film after film formation, and as ○ when scratched or peeled. Then, the evaluation results of each sample are shown in Table 1 together with the presence / absence of the bombarding treatment, the presence / absence of the discharge electrode 17, and the feeding speed of the flexible support.

[0042]

[Table 1]

From this, it is understood from the comparison between Example 1 and Comparative Example 1 that the provision of the discharge electrode 17 enables the film formation at a high feed rate. Further, comparing Comparative Example 1 and Comparative Example 2, it can be seen that the adhesion of the thin film is improved by the bombarding treatment. Further, in Example 1, since the adhesion of the thin film is good without performing this bombarding treatment, it can be seen that the discharge electrode 17 also has the effect of the bombarding treatment.

Experiment 2 Next, the thin film manufacturing apparatus described above (shown in FIG. 1).
Was applied to form a protective film on a magnetic recording medium.

First, on a non-magnetic support having an undercoat,
Using a general continuous winding type oblique vapor deposition apparatus, Co-
A Ni-based metal magnetic thin film was applied. Base used,
The undercoating and vapor deposition conditions are as follows. Non-magnetic support conditions Base: Polyethylene terephthalate 10 μm thickness 150 mm width Undercoat: Water-soluble latex containing acrylic ester as the main component Projection density approx. 10 million pieces / mm ² Vapor deposition conditions Ingot: Co80-Ni20 Ratio) Incident angle: 45 to 90 ° Tape speed: 0.17 m / sec Magnetic layer thickness: 0.2 μm Oxygen introduction amount: 3.3 × 10 ⁻⁶ m ³ / sec Vacuum degree: 7 × 10 ⁻² Pa

During the film formation of the metal magnetic thin film, a bombarding treatment was performed in order to enhance the adhesiveness with the non-magnetic support.

Next, a protective film was formed by the thin film manufacturing apparatus of FIG. 1 described above. The sputtering conditions are shown below. Sputtering conditions Method: DC magnetron sputtering method Target material: Carbon Gas used: Argon Vacuum degree in apparatus: 4 × 10 ⁻³ Pa Vacuum degree during film formation: 2 Pa Protective film thickness: 0.015 μm

When forming the protective film, the discharge electrode 1
Electric power of 350 V and 0.5 A was supplied to the No. 7 from the DC power source, and 8 W / cm ² of electric power was applied to the backing plate 11 of the cathode unit 9. Further, the feed rate of the flexible support 5 was adjusted so that the thin film thickness was 0.015 μm under the above-mentioned sputtering conditions.

Further, after forming a protective film under the above conditions, a back coat and a top coat were applied under the following conditions and cut into a predetermined tape width to obtain a sample tape (Example 2). Back coat: A mixture of carbon and urethane binder is applied to a thickness of 0.6 μm Top coat: Perfluoropolyether is applied Slit width: 8 mm width

When the protective film is formed, the cathode unit 9
A sample tape of Comparative Example 3 was prepared in the same manner as in Example 2 except that the device in which the discharge electrode 17 was not arranged in the vicinity of was used. In addition, in Example 2 and Comparative Example 3, the bombarding treatment was not performed at the time of forming the protective film.

Experiment 3 Next, using the apparatus in which the EB gun is arranged instead of the discharge electrode 17 in the thin film manufacturing apparatus described above,
The protective film was formed as follows.

In the apparatus used here, as shown in FIG. 5, the discharge electrode 17 is not arranged, but the electron supply port of the EB gun 22 is arranged so as to face the surface of the target material 10. The electron beam is supplied to the target material 10 by the EB gun 22, except for the traveling system for traveling the flexible support 6, the cathode unit 9 and the like, and the thin film manufacturing apparatus of FIG. 1 described above. It has the same configuration as the above.

The EB gun 22 is connected to a turbo molecular pump 24 via a valve 23, and local exhaust can be performed independently of a pump for exhausting the vacuum chamber 2. In the present apparatus, by performing such differential evacuation, the inside of the EB gun 22 and the vacuum chamber 2 are
The difference in the degree of vacuum from the inside can be two digits or more. EB
The electron supply by the gun 22 can be performed more efficiently as the degree of vacuum is higher. Therefore, when the EB gun 22 is used, the local exhaust is performed.

Here, as the EB gun 22, the piercing type (straight type) is used, but it is generally used 27.
A 0 ° deflection type can also be used.

In the thin film manufacturing apparatus, the vacuum chamber 2 is evacuated from the exhaust ports 1a and 1b to maintain a certain degree of vacuum, and the target material 10 is EB-treated.
Sputtering is performed while supplying electrons with the gun 22, and a film is formed on the flexible support 5 running on the peripheral surface of the cylindrical can 6. In addition, generally, in order to improve the adhesion between the flexible support 5 and the metal or the like to be deposited, a bombarding treatment may be performed in advance just before the deposition, but this bombarding treatment is not performed in this embodiment. It was

A magnetic tape was prepared in the same manner as in Example 2 except that the protective film was formed by the thin film manufacturing apparatus using the EB gun as described above. The power applied to the cathode unit 9 when forming the protective film of the sample tape of the third embodiment was 8 W / cm ² as in the second embodiment, and the power applied to the EB gun 22 was 20 kV, 0.1 A. It will be.

Evaluation of Characteristics With respect to the sample tapes of Examples 2 and 3 and Comparative Example 3 produced as described above, the adhesion of the formed protective film was measured in Experiment 1 after forming the protective film. Evaluation was made in the same manner as in. And the evaluation results of each sample tape,
Table 2 shows the presence / absence of the bombarding treatment, the presence / absence of the discharge electrode 17, and the feeding speed of the flexible support.

[0058]

[Table 2]

As a result, the protective film formed by any manufacturing apparatus had no problem in adhesion, but by disposing the discharge electrode 17 or the EB gun 22 in the vicinity of the cathode unit 9, the film formation rate is significantly increased. You can see that it is improving.

Then, the above-mentioned Examples 2 and 3 and Comparative Example 3
The sample tape was measured for still durability and rust resistance. Still durability is measured by Sony 8mmV
Using a modified TR EV-S900, the still durability time was defined as the time when the output dropped from the reproduction output level by 3 dB or more.

On the other hand, for the rust resistance, the measured value before the corrosion test is φ
s, the measured value after the corrosion test was φs ′, and the deterioration rate Δφs of the magnetic properties was obtained by the equation (1) for evaluation. Δφs = (φs−φs') / φs × 100 (%) (1)

In the corrosion test, a gas corrosion tester is used,
It was carried out by storing for 24 hours in an atmosphere (temperature 30 ° C., relative humidity 90%) containing 0.3 ppm of SO ₂ gas. Table 3 shows these measurement results.

[0063]

[Table 3]

From Table 3, it can be seen that the sample tapes of Examples 2 and 3 were still film-formed at a remarkably high film-forming rate as shown in Table 2, but still durable and rust-proof. It turns out that it is also excellent.

[0065]

As is apparent from the above description, when the thin film manufacturing method of the present invention is applied and an EB gun or discharge electrode is arranged in the vicinity of a cathode unit and sputtering is performed, the film formation rate is increased. improves. Further, when the present invention is applied to the formation of the protective film of the magnetic recording medium, the productivity is improved and the magnetic recording medium having excellent durability can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a thin film manufacturing apparatus used in the present invention.

FIG. 2 is a sectional view schematically showing a cathode unit in a thin film manufacturing apparatus used in the present invention.

FIG. 3 is a plan view schematically showing a cathode unit in the thin film manufacturing apparatus used in the present invention.

FIG. 4 is a cross-sectional view schematically showing a discharge electrode arranged in the thin film manufacturing apparatus used in the present invention.

FIG. 5 is a schematic diagram showing another configuration example of the thin film manufacturing apparatus used in the present invention.

[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 material 11 ... Backing plate 12, 13 ... Magnet 14 ... Cathode case 15 ... Cathode cover 17 ... Discharge electrode 18 ... Gas introduction tube 19 ... Discharge part 20 ... Insulation part 21 ... Magnet 22 ... EB gun 23 ... Valve 24 ... Turbo molecular pump

Claims (2)

[Claims] 1. A method of manufacturing a thin film in which a target placed on a cathode unit is sputtered to form a thin film, wherein an electron supply means or a discharge electrode is arranged in the vicinity of the cathode unit, A method for producing a thin film, characterized in that the film is formed while supplementarily supplying electrons or discharging. 2. The method for producing a thin film according to claim 1, wherein the electron supply means is an electron gun.