JPH0246529A - Method for manufacturing perpendicular magnetic recording media - Google Patents

Abstract

PURPOSE:To enhance coercivity of the magnetic layer and to obtain high coercivity at low substrate temperature by irradiating the surface of the polymer substrate with an electron beam during the magnetic layer is formed. CONSTITUTION:While the long polymer substrate 2 wound off from a releasing roll 1 travels along the side of a cylindrical can 3, it is subjected to vapor deposition of a CoCr film or CoCrNi film from a vapor source 4 through the apperture of the mask 7 and then wound up by a roll 5. A bias roller 6 is used to make the substrate 2 adhere to the can 3. An electron beam 9 is emitted by an assisting electron gun 8 through the apperture of the mask 7 to irradiate the polymer substrate 2 during the film is formed. Either a direct-type or 270 deg. deflection-type gun can be used for the electron gun which scans the substrate surface in the longitudinal and transverse directions. Thereby, vertical corecivity can be increased, so that higher coercivity can be obtained than in conventional medium at a same substrate temperature. Namely, high coercivity at lower substrate temperature can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a perpendicular magnetic recording medium having excellent magnetic properties.

BACKGROUND OF THE INVENTION Perpendicular magnetic recording has been widely studied as a next-generation high-density magnetic recording system. CoCr is used as a perpendicular magnetic recording medium.
CoCr perpendicular magnetic A-7 recording media (hereinafter abbreviated as CoCr film) have been researched and developed using sputtering and vacuum evaporation methods. Among them, when a vacuum evaporation method is used, a CoCr film can be formed at a deposition rate of several hundred nanometers per second or more, and is excellent in mass productivity.

Problems to be Solved by the Invention As mentioned above, by using the vacuum evaporation method, Co can be deposited at a high deposition rate.
Although it is possible to form a Cr film, at the same substrate temperature, as the deposition rate increases, the coercive force of the film decreases. Therefore, in order to obtain a sufficient coercive force, it is necessary to increase the substrate temperature as the deposition rate increases, and therefore a technique for obtaining a high coercive force at a lower substrate temperature has been desired.

Means for Solving the Problems The present invention is a means for solving the above-mentioned problems, and is a method for manufacturing a long magnetic recording medium that runs along the circumferential side of a cylindrical can, in which the magnetic layer is formed. This method of manufacturing a perpendicular magnetic recording medium comprises irradiating an electron beam onto the surface of the polymer substrate which is being processed.

Function According to the present invention, the coercive force of the magnetic layer that is being formed can be increased by irradiating the magnetic layer with an electron beam, so that a high coercive force can be obtained at a low substrate temperature.

Embodiment FIGS. 1 to 3 show an embodiment of the present invention. While the long polymer substrate 2 unwound from the unwinding roll 1 is traveling along the circumferential side of the cylindrical can 3, it is exposed to the evaporation source 4 at the opening of the mask 7 to deposit a CoCr film or a CoCrNi film. After receiving it, it is wound up on a winding roll 5. The bias roller 6 is used to bring the polymer substrate 2 into close contact with the can 3.

At this time, in the opening of the mask 7, an electron beam 9 is irradiated from an assisting electron gun 8 onto the polymer substrate 2 in the film growth process. As the assisting electron gun 8, a straight gun and a 27o
Although any zero deflection type electron gun can be used, it is necessary to scan the substrate surface in the substrate width direction and the substrate longitudinal direction.

Figure 2 shows CoCr deposited on a polyimide substrate 2 with a thickness of 10 μm at a can temperature of 2000 C and a deposition rate of 600 nm/s.
FIG. 7 is a diagram showing the relationship between assisting electron beam power density P and vertical coercive force Hc when a film is formed. The voltage applied to the bias roller was -200 cm. As can be seen from FIG. 2, by irradiating the electron beam from the surface side of the polymer substrate during film formation, the vertical coercive force increases.

Figure 3 shows Co deposition using a polyimide substrate 2 with a thickness of 12 μm at a can temperature of 160°C and a deposition rate of 500 nm/s.
FIG. 3 is a diagram showing the relationship between assisting electron beam power density P and vertical coercive force H3 when a Cr Ni film is formed. The voltage applied to the bias roller 6 is 200V. Also in FIG. 3, the vertical coercive force increases due to electron beam irradiation.

The reason why the vertical coercive force increases due to electron beam irradiation is considered to be as follows. That is, irradiation with the electron beam 9 increases the energy on the surface of the substrate during film formation.
It is thought that since the movable distance of the vapor-deposited atoms attached to the substrate 2 on the film surface becomes longer, the 5-vano Cr polarization progresses toward the grain boundaries, increasing the perpendicular coercive force. Also, when using an ion gun, coercive force may decrease, but this is different from this because the mass of the electron is small, so even if it collides with the membrane, it will not cause a collision like that seen when ions collide. This seems to be due to the fact that only the time during which atoms on the substrate surface can move becomes longer in a state where no cascade is generated and the grain boundaries are preserved.

Further, by applying a bias voltage to the bias roller 6, the substrate 2 and the can 3 are brought into close contact with each other.
It is thought that the entire body is not uniformly extremely hot, but that the heat flux in the thickness direction of the substrate is increasing, and the temperature gradient in the thickness direction is becoming larger.Can 3 is heated to a high temperature and the coercive force is increased. It is considered that the thermal load that the substrate 2 receives is smaller than that in the case where the substrate 2 is exposed to heat.

Effects of the Invention According to the present invention, the perpendicular coercivity can be increased at the same can temperature, and a perpendicular magnetic recording medium having excellent magnetic properties can be manufactured.

A-7

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the overall configuration in an embodiment of the present invention, and FIG. 2 is a diagram showing assist electron beam power density and CoCr
FIG. 3 is a diagram showing the relationship between the perpendicular coercive force of the CoCrNi film and the assisting electron beam power density. 2. Polymer substrate, 3. Can, 4. Evaporation source, 8. Assisting electron gun, 9. Electron beam.

Claims (1)

[Claims] Co and Cr or Co and Cr are deposited on a long polymer substrate running along the circumferential side of the cylindrical can by vacuum evaporation.
A method for manufacturing a perpendicular magnetic recording medium in which a magnetic layer containing Ni as a main component is formed, the perpendicular magnetic recording medium comprising: irradiating an electron beam onto the surface of the polymer substrate on which the magnetic layer is being formed. manufacturing method.