JPS59117738A - Manufacture of vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a long-sized magnetic tape or the like whose magnetic film has a uniform thickness and a uniform composition consisting of Co and Cr by adding preheated Cr to an evaporating source when a vertically magnetizable film consisting essentially of Co and Cr is formed on a substrate. CONSTITUTION:A substrate 1 is sent from an unwinding system 3 to a winding system 4 along a drum 2, and a Co-Cr film is deposited on the substrate 1 from a Co-Cr evaporating source 5 by a vacuum deposition method. When the deposition is continued using the source 5, the amount of Cr in the composition of the resulting magnetic film decreases gradually because Cr has higher vapor pressure. In order to prevent the decrease, Cr particles are preheated to >=400 deg.C with a preheater placed around a Cr feeder 6, and the preheated Cr particles 14 are uniformly added to the source 5 while shaking a Cr feeding pass with a device 7 in the latera direction of the substrate. Thus, a magnetic film having a uniform thickness and a uniform composition can be formed rapidly on the long- sized substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a perpendicularly magnetized film suitable for ultra-high density magnetic recording.

Conventional configuration and its problems Perpendicular magnetic recording is effective when performing magnetic recording with a short recording wavelength. In a recording medium for perpendicular magnetic recording, the direction of easy magnetization must be perpendicular to the surface of the medium film.

One of the recording media having such characteristics is a recording medium containing Go and Cr as main components (hereinafter this film will be referred to as a Go-Cr film).

The co-Cr film can be produced by either a sputtering method or a vacuum evaporation method. In particular, the latter method can achieve a film deposition rate of several 1000 λ/sec and has high productivity.

FIG. 1 is a diagram showing an example of an apparatus for producing a Go--Cr film on a long substrate by a vacuum evaporation method. In the vacuum chamber 11 evacuated to high vacuum by the illumination 2,
The substrate 1 unwound from the unwinding system 3 in the rotation direction 13 moves along the drum 2, and is irradiated with an electron beam 9 from the electron gun 1Q at the opening of the mask 8 (Eo -Cr
Co by the alloy evaporation source 6.

-A Cr film is vacuum-deposited and wound onto the winding system 4.

However, in this method, since the difference in vapor pressure between Co 2 and Cr is large, the composition of the evaporation source becomes a composition containing less Cr as the deposition time progresses. Therefore, as the deposition time progresses, the composition of the vacuum-deposited film becomes less Cr, resulting in a long Go-Cr film with a stable composition.
OBJECT OF THE INVENTION The object of the present invention is to manufacture a co-Cr film on a long substrate, which is stable in both composition and film thickness in the longitudinal direction of the substrate.

Structure of the Invention The present invention relates to the production of a magnetic recording medium in which a perpendicularly magnetized film containing Go and Cr as main components is formed on a substrate.
Perpendicular magnetic recording is characterized in that when Co and Cr are deposited on a substrate on which Co and Cr are transferred by an electron beam method, and when additional Cr is added, the additional Cr is preheated. This is a method for manufacturing a medium, whereby a Co-Gr film that is stable in both composition and film thickness in the longitudinal direction of the substrate can be manufactured on a long substrate.

Description of Examples In order to prevent the Cr agglomeration in the evaporation source from decreasing as the evaporation time elapses, additional Qr is added to the evaporation source in parallel with the vacuum evaporation, thereby achieving compositionally stable evaporation over a long period of time. As a result of experiments, it became clear that this could be done.

An example of a device for additionally introducing Qr is shown in FIG. Note that FIG. 2(a) is a side view, and FIG. 2(b) is a plan view of the main part. The substrate 1 unwound from the unwinding system 3 in the rotational direction 13 moves along the tram 2 and is exposed to C at the opening of the mask 8.
By the Cro-Cr alloy evaporation source 5, which is supplied with Cr14 for additional input from the r supply device 6 via the supply path,
A Go-Cr film is vacuum-deposited and wound onto a winding system 4.

With this method, compared to the conventional method, J〈It,'j
However, Go
-When additional Or is added into the Or alloy evaporation source, the temperature of the evaporation source instantaneously decreases each time, resulting in a Qo
It has been experimentally revealed that the variation in the amount of evaporation from the -Cr alloy evaporation source, that is, the variation in the thickness of the vacuum-deposited Go-C1 film, becomes larger than when Or is not added. For this reason, for example, if you try to cut a long Go-Or film in the longitudinal direction after manufacturing and use it as a long tape with a narrow width, you will not be able to obtain a tape with stable characteristics due to the film thickness variation described above. , so the inventors added O
By preheating r before introducing it into the co-Cr alloy evaporation source, an attempt was made to reduce the two series of film thickness fluctuations.
It has been found that the film thickness variation can be reduced by preheating, and in particular, when preheating to about 400''C or higher, the effect of additional Cr addition is almost eliminated.

In addition, as an example of a method for preheating Cr to be added, Ca
r Wrap a nichrome wire around the outer circumference of part of the supply device and heat it for a few minutes just before additional charging.
I tried to stop at a minute.

The temperature of the additional Cr is measured using a thermocouple inserted between the Cr grains.
The temperature was set.

FIG. 3 is a diagram for explaining an example of a method for preheating additional Cr. While the Cr charged in the Or filling part 15 for additional medicinal feeding is passing through the supply path 16,
It is heated by a heater 17 arranged so as to be wound around it, and its approximate temperature is measured by a temperature sensor 18, and then supplied from a supply port 19 to a Co--Cr alloy evaporation source.

FIG. 4 shows the relationship between the temperature of Qr added and the variation in the thickness of the Qo-Cr film. In addition, the horizontal axis is the additional input of Cr.
The vertical axis shows the range of film thickness variation over 10 minutes measured with a transmitted light film thickness meter. The Qr to be added is a fake grain with an average particle size of 3 mfn, and the Or of this grain is 4KW.
Go with a mass of about 660y receives the electron beam input of
-Car alloy was added to the evaporation source at a rate of about 5 g/min. The deposition rate of the Go-Cr film is about 5000 A/sec. The substrate movement speed is approximately sm/min.

On the other hand, when conducting the experiment with the other conditions the same without adding Or, the width of the film thickness fluctuation for 3 minutes is the second
It was distributed in the range between the two broken lines in the figure.

As is clear from FIG. 4, the higher the temperature of the additional Qr, the smaller the variation in the thickness of the Go-Or film. In particular, when the temperature of the additional Or added is about 400"C or higher, the film thickness variation is almost constant and is almost the same as when no additional Or is supplied. In other words, the film thickness variation is very small and the composition is A stable CoCr film can be produced. 5. Figure 5 shows the average particle size of Qr and G
The relationship with the film thickness variation of the o-Cr film is shown. Note that the horizontal axis represents the average particle diameter of additionally added Cr, and the vertical axis represents the range of film thickness variation over 10 minutes as measured by a transmitted light film thickness meter.

The temperature of additional Cr is approximately 20 PaC (without preheating) ~
A mass of 650 y received 4 KW of electron beam input and granulated Cr preheated to approximately 600”C.
It was added to the Go-Car alloy evaporation source at a rate of about 62/min. The deposition rate of the Go-Cr film is p, 1
It is 5000λ/sec. The substrate moving speed is approximately 8 m/min.

From FIG. 5, it can be seen that the smaller the average particle diameter of the additionally added Or, the smaller the fluctuation width of the film thickness. In addition, for each average particle size of additionally added Cr, the higher the preheating temperature, the more
It can also be seen that the film thickness variation due to Qr input tends to be smaller. Furthermore, the average particle size of the additionally added Or is 6 mr.
It is also clear that at a temperature below about n, if preheating is performed to about 400° C. or higher, the film thickness variation due to the addition of Or can be almost eliminated.

Figure 6 shows G produced on a long substrate with additional addition of Cr.
Fig. 3 shows the compositional fluctuation of the o-Cr film in the longitudinal direction of the substrate.

Note that the horizontal axis represents the position in the longitudinal direction of the substrate, and the vertical axis represents the position of Qr in the film.
Each represents the weight section. The additional Qr added had an average particle size of about 3 mm, and was preheated to about 400'C.

In a Go-Gr alloy evaporation source with a mass of about 550/' that receives electron beam input of 4 floods, Or
was added to increase the deposition rate of the Go-Cr film to about 50%.
I got 00λ/sec. The thickness of the manufactured GO-Cr film was approximately 1600A.

Effects of the Invention According to the present invention, a C0-Cr film having both stable composition and film thickness in the longitudinal direction of the substrate can be manufactured on a long substrate.

[Brief explanation of drawings]

Figure 1 is a diagram showing an example of the configuration of an apparatus for carrying out the continuous winding vacuum evaporation method of Co-0r film.
An example of the basic configuration of a device for additionally introducing r 2 is shown, in which FIG. 5A is a side view and FIG. Fig. 3 shows an example of a Qr supply device with a preheating function for carrying out the method of the present invention, and Fig. 4 shows the relationship between the temperature of additionally charged Cr and the film thickness variation of the C0-Cr film. Figure 5 shows the average particle diameter of additionally added Qr and Co-0.
FIG. 6 is a diagram showing the relationship with the film thickness variation of the r film, and FIG. 6 is a diagram showing the composition variation in the longitudinal direction of the substrate of a Go-Cr film manufactured on a long substrate. 1 board, 2 drum, 3 unwinding system, 49
′, 1LLf-him, 1o ′, Ii child Ljc, 1
1 l'l, empty tank, 12 4J1 gas system, 13
Rotation direction, 14 additional charging or, 15--or filling section, 16 supply path, 17 heater, 18 temperature control,
19 Supply port. Name of agent: Patent attorney Toshio Nakao and 1 other person-2
1: Fig. 1 Fig. 2 (b > Fig. 3 j b 1) 101 pieces 1'6 Cr' 44 ('07A
Figure 5

Claims (2)

[Claims] (1) In manufacturing a magnetic recording medium in which a perpendicularly magnetized film containing Co and Qr as main components is formed on a substrate, CO and Qr are deposited on the moving substrate by an electron beam method, and then evaporated. 1. A method for producing a perpendicular magnetic recording medium, which comprises preheating Qr for additional charging when additionally charging Qr to a source. (2) ・11J7 of the request for a complete feature that the Qr for additional input is preheated to about 400″C or higher
A method for manufacturing a perpendicular magnetic recording medium according to item 1.