JPH07113162A - Method and device for manufacturing thin film - Google Patents

Abstract

PURPOSE:To stably manufacture the thin film by the method and device for manufacturing the thin film. CONSTITUTION:In the device and method for manufacturing the thin film where the thin film is formed on a polymer substrate 4 which moves along the surface of a cylindrical can 5 in the vacuum by the electron beam deposition method, two or more opening parts of a buffle plate 9 to limit the angle of incidence of the vapor in forming the thin film are provided, the thickness of the thin film to be formed at a first opening part 13 provided on the initial side in forming the film is set to be over 0nm to 3nm inclusive, and the substrate is closely adhered to the cylindrical can be the reflected electron of the electron beam at the first opening part. By this constitution, the thin film with excellent properties can stably be obtained.

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 and manufacturing apparatus.

[0002]

2. Description of the Related Art The role of thin films in modern society is extremely widespread, and thin films are used in various parts of daily life. Also in the field of magnetic tapes, research and development of thin film magnetic recording media have been actively conducted with the aim of increasing the density of recording media. Among high-density thin film magnetic recording media, Co-based oxide thin films have already been commercialized as video tapes.
It is getting attention.

As a method for producing a tape-shaped Co oxide thin film magnetic recording medium, the continuous winding electron beam vapor deposition method is particularly superior in productivity. That is, magnetic recording media can be mass-produced by electron beam evaporation of a magnetic layer while a long polymer substrate is running along the circumferential surface of a cylindrical can as shown in FIG. A long magnetic tape can be produced by using Co or Co—Ni as a magnetic material and performing vapor deposition in an oxygen atmosphere.

[0004]

In forming a thin film on a polymer substrate by electron beam evaporation, it is essential to prevent thermal damage to the polymer substrate. The higher the speed of forming the thin film, the higher the input power to the electron beam evaporation source, and the heat radiation from the evaporation source and the heat of condensation of vapor deposition atoms flying at a high deposition rate increase more and more. Therefore, electron beam irradiation is performed as a means for closely contacting a polymer substrate with a cylindrical can to release the heat load during film formation to the can. That is, as shown in (FIG. 3), when the surface of the polymer substrate is irradiated with an electron beam from the attachment electron gun after the polymer substrate is in contact with the can, the polymer substrate comes into close contact with the can, and then the process is continued. It is possible to prevent thermal damage to the substrate during vapor deposition.

However, if an independent electron gun for attachment is installed, the equipment becomes large-scale, and the equipment investment and operating cost increase.

[0006]

In order to solve this problem, the present invention provides a thin film by electron beam vapor deposition on a polymer substrate which moves along the surface of a cylindrical can in vacuum, either directly or through an underlayer. In the method of manufacturing a thin film for forming a thin film, two or more openings of a shielding plate for limiting the vapor incident angle when the thin film is formed are formed in the first opening provided on the initial side of film formation. Wherein the thickness of the thin film is more than 0 and within 3 nm, and the substrate is brought into close contact with the cylindrical can by reflected electrons of the electron beam at the first opening, and in a vacuum. In a thin film manufacturing apparatus for forming a thin film on a polymer substrate running along the surface of a cylindrical can by an electron beam evaporation method directly or through an underlayer, the vapor incident angle at the time of forming the thin film is The opening of the shielding plate is limited to two or more places, and the first opening is provided on the initial side of the film formation and in the area where the reflected electrons from the electron beam evaporation source fly. Further, in the first opening. It is characterized in that the thickness of the thin film formed is determined so as to exceed 0 and be within 3 nm.

[0007]

[Function] Even if an independent electron gun is not provided for pasting,
Since the polymer substrate can be brought into close contact with the cylindrical can by the backscattered electrons from the evaporation source that has entered the first opening provided in the initial portion of vapor deposition, heat damage to the polymer substrate can be prevented. Further, since the thin film formed in the first opening has a small thickness, it has almost no effect on the characteristics of the entire thin film.

[0008]

EXAMPLE An example of the present invention will be described below with reference to FIG. The long polymer substrate 4 unwound from the unwinding roll 3 along the rotation direction 12 in the vacuum chamber 2 evacuated by the evacuation system 1 extends along the surfaces of the guide roll 11 and the cylindrical can 5. After being subjected to vapor deposition in the openings 13 and 14 of the shield plate 9 from the electron beam evaporation source 7 which is irradiated with the electron beam 6 from the electron gun 18 during traveling,
It is wound around the take-up roll 10. The polymer substrate is irradiated with the backscattered electrons reflected from the evaporation source 7 in the first opening provided in the initial portion of the vapor deposition after the polymer substrate is provided along the circumferential surface of the cylindrical can. The backscattered electrons move while repeatedly colliding with the wall surface of the vacuum chamber, and are irradiated onto the polymer substrate reaching the first opening 13 at various incident angles. By the irradiation of backscattered electrons, the adhesion of the polymer substrate and the electrostatic attraction of the can is increased,
The thin film is formed without thermal damage to the substrate.

Although the amount of backscattered electrons naturally increases as the opening width of the first opening 13 increases, the thickness of the thin film formed in the first opening also increases as the opening width increases.
Therefore, the film thickness of the thin film formed in the first opening must be within a range that has a small effect on the characteristics of the entire thin film, and the opening width of the first opening is determined by the balance between the adhesion of the substrate and the film characteristics. Decided.

Polyethylene terephthalate (PET) and polyethylene naphthalate (PE) as polymer substrates
N) Using a substrate, Co was used as a vapor deposition material in an oxygen atmosphere to form a Co oxide thin film with a film thickness of 50 nm to 200 nm by an electron beam vapor deposition method. The sticking electron gun as described above (FIG. 3) is not used. The opening of the vapor shielding plate was provided at two places, and the width of the first opening was changed by keeping the vapor incident angle at the second opening constant at 70 to 50 degrees from the normal to the polymer substrate. The film thickness of the thin film formed in the first opening was determined by closing the second opening and forming the thin film only in the first opening. The film thickness of the thin film formed in the first opening was obtained from the transmission electron microscope image of the fracture surface. When the film thickness is very thin, the transport speed of the polymer substrate was slowed to perform vapor deposition. Was calculated to be inversely proportional to the transport speed. Table 1 shows film forming conditions and vapor deposition results. The vapor deposition results were evaluated by the squareness ratio, which indicates the ratio of the residual magnetization to the saturation magnetization of the in-plane magnetization curve of the film and the applied magnetic field of zero, with respect to the substrate thermal damage. Further, in Table 1, the thickness of the first opening is 0 when the first opening is completely closed.

[0011]

[Table 1]

As can be seen from (Table 1), the thermal damage to the polymer substrate can be prevented by providing the first opening without using the attachment electron gun. Further, when the thickness of the thin film formed in the first opening is 3 nm or less, the squareness ratio is 0.90 or more, and the squareness ratio equal to or higher than that in the case where the first opening is not provided is obtained. There is. It should be noted that the squareness ratio when the attachment electron gun is used and the first opening is not provided is 0.
It was 90. As a result of not using the attachment electron gun (Table 1), the squareness ratio when the first opening is closed is slightly smaller than 0.9 because gas is generated due to thermal damage of the polymer substrate. It seems that the film growth was disturbed by this and the squareness ratio was lowered.

FIG. 4 is a diagram showing a case where the substrate is irradiated with ions prior to vapor deposition in the present invention. A Kauffman type ion source was used for ion irradiation, and argon ions with a beam voltage of 400 V and an acceleration voltage of 200 V were irradiated with 1 mA per 1 cm 2 together with neutralizing electrons while passing through the ion irradiation portion. The thickness of the thin film to be formed was 200 nm. (Table 2) shows the same experimental results as in (Table 1) with and without ion irradiation.

[0014]

[Table 2]

As can be seen from Table 2, when the ion irradiation is performed, the substrate is not thermally damaged up to a higher substrate temperature (can temperature) than when the ion irradiation is not performed. It is considered that this is because the ion irradiation is performed after the substrate comes into contact with the can to remove the charge and degas the substrate, thereby increasing the adhesion between the substrate and the can when the reflected electrons are irradiated.

From the experimental results described so far, it is important for the first opening to take in as many reflected electrons as possible and not take in a lot of evaporated atoms in order to prevent thermal damage to the substrate and secure the thin film characteristics at the same time. . Therefore, from this viewpoint, the ratio of the opening width of the first opening in the substrate traveling direction to the total opening width of the entire opening is such that the thickness of the thin film formed in the first opening is the thin film. The first opening is defined by connecting the end of the opening of the shield plate with a straight line from the evaporation center of the evaporation source irradiated with the electron beam. Eliminating the direct source area of the evaporation source increases the effect of the present invention. Further, the effect of the present invention can be increased by providing an electric field generator or a magnetic field generator for causing the backscattered electrons near the first opening to swirl toward the first opening. . Table 3 is an experimental result showing that the effect of the present invention is increased by providing an electric field generator and a magnetic field generator. The thickness of the thin film to be formed was 200 nm. The electric field was generated by providing an electrode of −10 kV near the first opening, and the magnetic field was generated by installing a water-cooled samarium-cobalt permanent magnet near the first opening. The experiment shown in (Table 3) was performed without ion irradiation.

[0017]

[Table 3]

As shown in (Table 3), the use of the electric field generator or the magnetic field generator prevents thermal damage to the polymer substrate up to a high substrate temperature. As described above, by providing an electric field generator or a magnetic field generator for causing the backscattered electrons near the first opening to swirl toward the first opening, the first opening is provided. It is considered that the adhesiveness between the substrate and the cylindrical can increased due to the increase of backscattered electrons taken in the part.

Although only the case of using polyethylene terephthalate and polyethylene naphthalate as the substrate in the examples has been described above, the polymer substrate such as polyester, polyamide, polyimide or the like is made to run along the cylindrical can. Any substrate material that can be used can be used. Further, although only the case of forming a Co—O magnetic layer as a thin film has been described as an example, when another oxide thin film such as Co—Ni—O is used as a magnetic layer, an Fe-based or other magnetic metal material is used. It is needless to say that the present invention is also effective in the case of using, when the magnetic layer is formed after the underlayer is formed prior to the formation of the magnetic layer, or when a thin film other than the magnetic layer is formed.

[0020]

As described above, according to the method and apparatus for manufacturing a thin film of the present invention, a thin film having excellent characteristics can be stably obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a method for producing a thin film of the present invention.

FIG. 2 is a diagram showing an example of a conventional method of manufacturing a thin film magnetic recording medium.

FIG. 3 is a diagram showing a general example of a conventional method for manufacturing a thin film magnetic recording medium.

FIG. 4 is a diagram showing an example of a method for producing a thin film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust system 2 Vacuum tank 3 Unwinding roll 4 Polymer substrate 5 Cylindrical can 6 Electron beam 7 Electron beam evaporation source 8 Gas introduction nozzle 9 Shielding plate 10 Winding roll 11 Guide roll 12 Rotation direction 13 First opening 14 Second opening 16 Contact electron gun 17 Contact electron beam 18 Electron gun

Claims (7)

[Claims] 1. A method for producing a thin film, which comprises forming a thin film on a polymer substrate moving along the surface of a cylindrical can in a vacuum by an electron beam evaporation method directly or through an underlayer, wherein the thin film is formed. In this case, two or more openings of the shielding plate for limiting the vapor incident angle are provided, and the thickness of the thin film formed in the first opening provided on the initial side of film formation is more than 0 and within 3 nm, A method of manufacturing a thin film, wherein the substrate is brought into close contact with the cylindrical can by reflected electrons of the electron beam in the first opening. 2. The polymer substrate starts along the cylindrical can, and the polymer substrate is irradiated with an ion current after that, and then the polymer substrate is guided to the first opening. The method for producing a thin film according to claim 1. 3. A thin film manufacturing apparatus for forming a thin film by a electron beam vapor deposition method on a polymer substrate running along the surface of a cylindrical can in a vacuum, directly or through an underlayer. In this case, two or more openings are formed in the shielding plate for limiting the vapor incident angle, and the first openings are provided in the initial side of film formation and in the area where the reflected electrons from the electron beam evaporation source fly. 2. The thin film manufacturing apparatus, wherein the opening width of the first opening is determined so that the thickness of the thin film formed in the opening is more than 0 and within 3 nm. 4. The ratio of the opening width of the first opening in the substrate traveling direction to the total opening width of the entire opening is such that the thickness of the thin film formed in the first opening is 4. The thin film manufacturing apparatus according to claim 3, wherein the ratio is larger than the ratio of the total thickness of the thin film. 5. The first opening does not include an evaporation source direct view area defined by connecting a straight line from the evaporation center of the evaporation source irradiated with the electron beam to the end of the opening of the shielding plate. The thin film manufacturing apparatus according to claim 3, wherein the thin film manufacturing apparatus is a thin film manufacturing apparatus. 6. The reflected electrons in the vicinity of the first opening are
The thin-film manufacturing apparatus according to any one of claims 3 to 5, further comprising: an electric field generating device for rotating the electric field toward the first opening. 7. The reflected electrons in the vicinity of the first opening are
The thin film manufacturing apparatus according to claim 3, further comprising a magnetic field generation device for rotating the magnetic field toward the first opening.