JPS59167851A - Method and apparatus for manufacturing magnetic recording medium - Google Patents

Abstract

PURPOSE:To attain the manufacture in high speed by providing a cooling drum made of a nonmagnetic stainless steel in a vacuum tank and directing a vapor flow of a ferromagnetic member to a base moving along the circumferential side face of the cooling drum from a ferromagnetic member vapor-deposition source so as to form the ferromagnetic metallic thin film layer on the base. CONSTITUTION:The inside of a vacuum tank 1 is kept vacuum by an exhaust system 2, the cooling drum 3 made of the nonmagnetic stainless steel is provided at the center of the vacuum tank 1 and a base 4 made of a polyester film is wound on a winding roll 8 from a payoff roll 5 via a guide roller 6 through the cooling drum 3 and a guide roller 7. The ferromagnetic member 10 is heated and evaporated by an evaporating source 9 to the base 4 moving along the circumferential side face of the cooling drum 3 during this time and the vapor- deposition is attained. A reflected electron preventing device 13 is provided between the cooling drum 3 and a deposition preventing plate 2, and the arrival of reflected secondary electrons to the base 4 when the ferromagnetic member 10 in the ferromagnetic member evaporating source 9 is evaporated is prevented effectively by applying a magnetic field to the device 13.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetic recording medium having a ferromagnetic metal thin film layer as a recording layer, and an apparatus used for carrying out the method.
The purpose is to provide a method for manufacturing the magnetic recording medium at high speed and efficiency without causing thermal deformation, and an apparatus used for carrying out the method.

Magnetic recording media with a ferromagnetic metal thin film layer as the recording layer are usually manufactured using a cylindrical cooling drum with a substrate such as a polyester film mounted in a vacuum chamber. ! It is made by moving the drum along one surface and vacuum-depositing a ferromagnetic material onto this substrate. Cooling drums generally have a drum body made of mild steel and a chrome-plated outer surface. It is used.

However, the conventionally used cooling drum made of mild steel with chrome plating on its outer surface has poor thermal conductivity and does not have sufficient cooling effect, especially when vacuum evaporation is performed at high speed. Pinholes and wrinkles may occur,
In extreme cases, the substrate may melt due to radiant heat from the ferromagnetic material evaporation source. In addition, when ferromagnetic material is heated and evaporated using a ferromagnetic material evaporation source, the ferromagnetic material is heated at a high temperature of approximately 2000°C, so the ferromagnetic material may bump and adhere to the cooling drum. If it adheres to the surface of the cooling drum, all the chrome plating must be removed to remove it, and the chrome plating must be applied again, which is very troublesome and it is not possible to polish the drum surface and reuse it as is. Can not. Furthermore, since the cooling drum of the mild steel section is magnetic, even if a backscattered electron prevention device is installed near the cooling drum to prevent secondary electrons reflected from the ferromagnetic material evaporation source from reaching the substrate, the backscattered electron The lines of magnetic force that effectively prevent backscattered electrons are absorbed by the cooling drum, making it impossible to effectively prevent secondary electrons from being reflected on the substrate, thereby preventing the substrate from being damaged by the reflection of secondary electrons. There are some drawbacks, such as the fact that it cannot be prevented.

As a result of various studies on cooling drums in order to improve these drawbacks, the inventor found that by using a cooling drum made of non-magnetic stainless steel and placing it in a vacuum chamber to perform vacuum evaporation, this type of The cooling drum has a high thermal conductivity and has a good cooling effect, so even if the substrate is moved at high speed along the circumferential surface of the cooling drum, the substrate can be sufficiently cooled. Vapor deposition can be performed at high speed without thermal deformation such as holes or wrinkles, and it is harder than conventional soft m cooling drums and does not have chrome plating on its outer surface. Even if ferromagnetic material bumps and adheres to the surface, it can be reused by simply polishing the surface of the cooling drum.Furthermore, since it is non-magnetic, secondary electrons reflected from the ferromagnetic material evaporation source are It was discovered that the damage to the substrate due to the reflection of secondary electrons can be effectively suppressed without absorbing the magnetic lines of force of the backscattered electron prevention device that prevents damage to the substrate, and this invention has been completed.

The present invention will be described below with reference to the drawings.

Figure 1 shows a cross-sectional view of the vacuum evaporation apparatus,
is a vacuum chamber, and the inside of this vacuum chamber 1 is maintained in a vacuum by an exhaust line 2. 3 is a cooling drum made of non-magnetic stainless steel disposed in the center of the vacuum chamber 1, and a substrate 4 such as a polyester film is passed from a raw roll 5 through a guide roller 6 to the circumferential side of the cooling drum 3. The substrate is moved along the substrate, is taken up by a take-up roll 8 via a guide roller 7, and is moved by such a substrate transfer mechanism. During this time, the ferromagnetic material evaporation source 9 disposed at the bottom of the vacuum chamber 1 faces the substrate 4 moving along the circumferential side of the cooling drum 3.
0 is heated and evaporated by the heating of the thermionic source 11, and this vapor flow is directed toward the substrate 4, and oblique incidence evaporation is performed by the action of the deposition prevention plate 3. 13 is a backscattered electron prevention device disposed between the cooling drum 3 and the adhesion prevention plate 2, and by applying a magnetic field to this backscattered electron prevention device, the ferromagnetic material evaporation source 9 is removed.
Secondary electrons reflected when the ferromagnetic material 10 inside is evaporated are effectively prevented from reaching the substrate 4.

Thus, in the present invention, the cooling drum 3 disposed in the center of the vacuum chamber 1 is preferably made of non-magnetic stainless steel, and the cooling drum made of this stainless steel has high thermal conductivity and is heat-resistant. Since it has excellent conductivity, it has a good cooling effect, and even if the substrate is moved at high speed along the circumferential surface of the cooling drum, the substrate can be sufficiently cooled. Therefore, vacuum deposition can be performed at high speed without causing thermal deformation such as pinholes or wrinkles, allowing efficient production and improving mass productivity. In addition, since it is non-magnetic, it does not absorb the magnetic lines of force of the backscattered electron prevention device 13, and can effectively suppress damage to the board due to reflection of secondary electrons. Since the cooling drum 3 is not coated, even if the ferromagnetic material bumps and adheres to the surface, the cooling drum 3 can be used as is by simply polishing the surface. The surface roughness of such a cooling drum is 2.0μ
It is preferable that the surface roughness is 2.0.
An austenitic non-rusting steel having a diameter of less than μ is preferably used.

As the substrate, a plastic film made of commonly used polymer moldings such as polyester, polyimide, polyamide, etc. and non-magnetic metals such as copper are used, and the formation of a ferromagnetic metal thin film layer on such a substrate is The ferromagnetic metal thin film layer is formed by means such as vacuum evaporation, sputtering, and ion blating.In addition to single metals such as cobalt, nickel, and iron, the material for forming the ferromagnetic metal thin film layer is
Alloys or oxides of these, Co P -, C
.

Commonly used ferromagnetic materials such as -Ni-P are used.

Next, embodiments of the invention will be described.

Example 1 As shown in FIG. 1, a vacuum evaporation apparatus was used in which a cooling drum 3 made of non-magnetic stainless steel and having a drum surface roughness of 0.5 μm was disposed in the center of a vacuum chamber 1. The polyester base film 4 is moved along the circumferential side of the cooling drum 3 from the raw roll 5 via the guide roller 6,
The sample was set to be wound onto a take-up roll 8 via a guide roller 7, and 10 pieces of a cobalt-nickel alloy (weight ratio 8:2) was placed in a ferromagnetic material evaporation source 9.

Next, the inside of the vacuum chamber 1 is evacuated to approximately 5 x 10'' l by the exhaust system 2, and the cobalt-nickel alloy 10 in the ferromagnetic material evaporation source is heated and evaporated by the thermionic source 11, and the polyester base film 4 is Vacuum deposition was performed by running at a speed of 50 m/min to form a polyester base film 4.
The top layer is made of cobalt-nickel alloy with a thickness of 0.1 μm.
A magnetic recording medium was created by forming a ferromagnetic metal thin film layer.

Comparative Example 1 In Example 1, instead of using a cooling drum made of non-magnetic stainless steel with a surface roughness of 0.5 μm, a drum body was made of soft 111 m long and had a surface roughness of 1 μm with chrome plating on its outer peripheral surface. A magnetic recording medium was produced in the same manner as in Example 1 except that a cooling drum of .0 μm was used.

Regarding the magnetic recording media obtained in Examples and Comparative Examples,
The presence or absence of pinholes and the occurrence of wrinkles were observed.

The table below shows the results.

As is clear from the above table, the magnetic recording medium obtained by the conventional method (comparative example) has pinholes and wrinkles, whereas the magnetic recording medium obtained by the apparatus and method of the present invention (comparative example) has pinholes and wrinkles. No pinholes or wrinkles were observed in Example), which shows that the manufacturing method of the present invention and the apparatus used to carry out the method can efficiently produce a magnetic recording medium free of thermal deformation at high speed. Recognize.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing one example of a vacuum evaporation apparatus used to carry out the manufacturing method of the present invention.

Claims (1)

[Claims] 1. A cooling drum made of non-magnetic stainless steel is disposed in a vacuum chamber, and a vapor flow of ferromagnetic material from a ferromagnetic material evaporation source is applied to a substrate moving along the circumferential side of the cooling drum. 2, a method for manufacturing a magnetic recording medium characterized by forming a ferromagnetic metal thin film layer on a substrate by directing a cooling drum made of non-magnetic stainless steel and a peripheral side surface of the cooling drum in a vacuum chamber; a substrate that moves along the circumferential surface of the cooling drum; a substrate transfer mechanism that moves and guides the substrate along the circumferential surface of the cooling drum; a ferromagnetic material evaporation source that faces the substrate that moves along the circumferential surface of the cooling drum; A deposition prevention plate that partially blocks the vapor flow from the ferromagnetic material evaporation source to the substrate as necessary, and a backscattered electron prevention plate that prevents secondary electrons reflected from the ferromagnetic material evaporation source from reaching the substrate. A magnetic recording medium manufacturing device comprising: