JPH0442730B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a magnetic recording medium used in a perpendicular recording system with excellent short wavelength recording characteristics.

Conventional configurations and their problems A perpendicular recording system has been developed as a recording system with excellent short wavelength recording characteristics, and with this, the production of recording media has become an important issue for the practical application of the system.

The recording medium used in the step of theoretical investigation of the recording method was obtained by sputtering deposition on the substrate.
The main types were those with a Co-Cr alloy film or those with a Co-Cr alloy film interposed through permalloy.
For mass production of recording media, sputtering evaporation is unsatisfactory in terms of film formation speed, and some studies are progressing on conditions based on vacuum evaporation as a new method for forming perpendicularly magnetized films; In order to obtain the desired magnetic properties, it is necessary to maintain the substrate temperature at 200°C or higher during film formation, making it impossible to use polyethylene terephthalate, which is the most excellent substrate.

Purpose of the Invention The present invention provides a method for manufacturing a magnetic recording medium that can produce a magnetic film that satisfies the magnetization characteristics of a perpendicular recording method even when a low melting point polymer material such as polyethylene terephthalate is used as a substrate. The purpose is to provide.

Structure of the Invention The method for manufacturing a magnetic recording medium of the present invention provides a method for manufacturing a magnetic recording medium according to the present invention.
At the same time as Co or Co-Ni alloy is deposited by electron beam, a non-magnetic Co-based alloy containing one element selected from Cr, Mo, V, w, Ru, or Sm is sputter deposited on the substrate. It is characterized by forming a Co-based alloy thin film having an axis of easy magnetization perpendicular to the plane.

Description of Examples Hereinafter, the manufacturing method of the present invention will be explained based on specific examples.

FIG. 1 is a main configuration diagram of a winding vapor deposition apparatus used to carry out the present invention. The substrate 1 is moved from the feed shaft 2 to the winding shaft 4 along the rotary cooling support 3.
It is rolled up and moved. Before the substrate 1 is wound up on the winding shaft 4, Co or Co-Ni is applied to the cooled substrate 1 along the rotating cooling support 3.
A first evaporation source ( ) is arranged such that a vapor stream 5 of the alloy is directed with angle of incidence regulation by a mask 6 . In FIG. 1, the first evaporation source ( ) is schematically shown as an electron beam heating method as a representative example. That is, the evaporation source container 7
An evaporative material 8 is placed in the evaporative material 8, and electrons emitted from an electron beam generator 9 are accelerated to impact and heat a part of the evaporative material 8, thereby creating the vapor flow 5. Also,
In FIG. 1, a sputter source is provided as a second evaporation source (), and a sputter cathode 10
As the material, a non-magnetic Co-based alloy material containing one element selected from among Sm, Cr, Mo, W, V, and Ru is used, which is bonded to the packing plate. Regarding the arrangement of the sputter cathode 10, a few experiments are required to optimize the conditions, but as shown in FIG. The cathode size and geometry are chosen to closely approximate what was determined in the drawing, so that the entire area of the substrate covered is covered.

The inside of the vacuum container 11 is divided by the mask 6 into a winding chamber 12 and an evaporation source chamber 13, and the winding chamber 12 contains a winding system and a sputter deposition system. Further, the evaporation source chamber 13 incorporates an electron beam evaporation system. Both spaces 12 and 13 are exhausted by exhaust systems 14 and 15, respectively, and normally discharge gas is forcibly introduced from the outside through a nozzle 17 in order to maintain the discharge by adjusting a barrier break valve 16 in the sputter deposition system. has been done. Although the vacuum container 11 is divided into the winding chamber 12 and the evaporation source chamber 13, this is not an essential requirement. Further, as a method for use in the sputter deposition system, either a DC magnetron method or a high frequency magnetron method is suitable.

Although FIG. 1 only shows the system used to form a perpendicularly magnetized film, the present invention also uses this apparatus to form a perpendicularly magnetized film using a substrate on which a predetermined thickness of permalloy, Cr, Ti, etc. has been formed in advance as an underlayer. Can be formed.

The substrate 1 is made of polyethylene terephthalate,
Polyimide, polyamide, polyethylene naphthalate, polyvinyl chloride, etc. are used, but as described later, even if polyethylene terephthalate is used, a perpendicularly magnetized film with satisfactory magnetic properties can be obtained without any thermal deterioration of the substrate. The thing is,
This is thought to be due to the large kinetic energy of sputtering atoms and the impact effects of active atoms, ions, and electrons on the substrate surface, which are maintained even when mixed with high-speed deposition of Co or Co--Ni.

Next, various experimental examples carried out using the apparatus shown in FIG. 1 will be explained.

[Example 1] Co
At the same time, Co-V (99.98%) was deposited at a deposition rate of 0.76 μm/min, and the average incident angle was close to 45°. Vapor deposition was performed at a deposition rate of 0.2 μm/min. At this time, Ar was introduced at 0.03/min to make the vacuum level 1×10 ^-4 Torr, and the spatter cathode 10 was
A high frequency of 13.56MHz was applied. Then, the C-axis dispersion of the Co-V film was investigated by changing the surface temperature of the rotating can.

The Co-V film was formed in a range of 0.06 μm to 0.46 μm. Further, the value of V was carried out in the range of 13% to 28% in atomic %.

FIG. 2 shows the vertical magnetization curve of a 0.15 μm V18.5 at% Co-V film, and it can be seen that an extremely good perpendicular magnetization film was obtained.

In Figure 3, the horizontal axis represents the surface temperature of the rotating can, which is a quantity related to the surface temperature of the substrate 1, and the half-width (△ The change in θ ₅₀ ) is shown in comparison with the conventional example. The comparative example () in Figure 3 is a case where a Co-V alloy is deposited by electron beam, and since the component ratio of V cannot be kept constant, samples with V values between 17.5 at% and 19 at% are extracted. This is the result of measurement. () is obtained by the manufacturing method of the present invention. From this Figure 3, it can be seen that an extremely small amount of improvement in the value of △θ ₅₀ is achieved by increasing the substrate temperature.
The absolute value changes in an extremely small area compared to the conventional example, and the medium produced by the manufacturing method of the present invention has
Any Δθ ₅₀ value is satisfactory.

[Example 2] Co85 was applied to a 10.5 μm polyethylene terephthalate film at an incident angle of 0° to 16°.
%Ni15% (alloy purity, 99.98%) 2.2μm/
Cr (99.99%) simultaneously deposited at a deposition rate of min
The first target was a Co-Cr alloy containing 34%
Co-Ni-
When the average angle of incidence of Cr atoms is close to 27°,
The deposition was performed at a sputter deposition rate of 0.48 μm/min. At this time, the amount of Ar introduced was 0.03/min, and the degree of vacuum was 1.8.
×10 ^-4 Torr, 13.56MHz to sputter cathode
high frequency was applied. The surface temperature of the rotating can is 10
The experiment was carried out at a temperature ranging from °C to 120 °C, and the vertical coercive force was 1300 [Oe] and Δθ ₅₀ was 4.5° to 4.7°.
Regarding the component ratio of Co−Ni−Cr, Co−Ni−Cr
For Co-Ni, the sputtering speed is fixed and the sputtering speed of Co-Ni is varied, and the sputtering speed of Co-Ni is fixed and the sputtering speed of Co-Ni-Cr is varied. Cr is 16 atomic%
% to 29%, the vertical coercive force was 1200 [O¨] to 1600 [O¨e], and △θ ₅₀ was 3.9
°
A membrane with a range of ~5.6° was obtained. In addition, for Co100%, W, Cr, Sm, Mo, and Ru are each 16− for Co.
The present invention was carried out by varying Cr, V, W, Sm, Mo, and Ru in the range of 16 to 33 at% with respect to the Co-Ni alloy for an alloy of 80% Co and 20% Ni with a range of 33 at%. carried out. In both cases, the substrate can hold a perpendicularly magnetized film of 0.03 μm to 0.6 μm without thermal deterioration.
It was possible to obtain high-speed deposition with an average deposition rate of 1.5 μm/min to 9.9 m/min.

In addition, we attempted to create a perpendicularly magnetized film under the above conditions by electron beam evaporation of a 0.1 μm permalloy thin film on 10.5 μm polyethylene terephthalate, but the performance obtained when the present invention was applied directly to polyethylene terephthalate was The magnetic properties were either the same or slightly improved.

In addition, Cr, Mo, V, W, Ru, and Sm, which are used to dilute the saturation magnetization of Co and improve the C-axis orientation, are deposited in an alloyed state with Co. , it is not possible to maintain a constant component ratio because the vapor pressure is significantly different from that of Co, but
The present invention has the advantage that the component ratio can be stably controlled over a long period of time, and as a result, uniformity of magnetic properties can be ensured.

The rotary cooling support 3 is not limited to the so-called rotary can shown in FIG. 1, but may also be a rotary belt.

INDUSTRIAL APPLICABILITY The present invention is useful for obtaining a perpendicularly magnetized film on a long, wide substrate wound into a roll, and is suitable for magnetic recording media such as tapes, disks, sheets, cards, etc. There are no restrictions whatsoever.

Note that the present invention can naturally be applied to heat-resistant substrates; for example, the present invention can be applied to a 25 μm polyimide substrate while maintaining the substrate temperature at 250°C.
Co80at% Cr20at%, 0.15μm vertical coercive force
1900 [Oe], △θ ₅₀ = 2.6°, and a perpendicularly magnetized film with the same configuration obtained only by electron beam evaporation without using the present invention had a coercive force of 1300 [O¨e], △θ ₅₀ = 4.9°. Compared to
This resulted in extremely excellent magnetic properties.

Effects of the Invention As explained above, according to the method of manufacturing a magnetic recording medium of the present invention, a heat-resistant Co or CoNi alloy thin film suitable for perpendicular recording, which has a large coercive force and good C-axis orientation, is produced. It can be obtained on a practical scale not only on a substrate but also on a low melting point substrate while ensuring high productivity and uniformity of properties over a long length.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of main parts of a winding vapor deposition apparatus used in a specific embodiment of the manufacturing method of the present invention;
FIG. 2 is a magnetic characteristic diagram of a typical example of a medium obtained by the present invention, and FIG. 3 is a comparative illustration of the dependence of C-axis orientation on support temperature between a medium produced by the manufacturing method of the present invention and a conventional medium. It is. DESCRIPTION OF SYMBOLS 1... Substrate, 3... Rotating cooling support, 8... Evaporation material, 10... Sputter cathode.

Claims (1)

[Claims] 1 At the same time as electron beam evaporation of either Co or Co-Ni alloy onto the substrate, Cr, Mo, V, W,
A method for producing a magnetic recording medium, comprising sputtering deposition of a non-magnetic Co-based alloy containing one element selected from Ru and Sm to form a Co-based alloy thin film having an axis of easy magnetization perpendicular to the substrate surface. .