JPS62231424A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which is stably obtainable with good workability and has good performances including durability, etc., by providing a layer which has <=0.05mm max. particle size and consists substantially of carbon on the upper side and/or lower side of a magnetic layer. CONSTITUTION:The layer which has <=0.05mm max. particle size and consists substantially of carbon is provided on the upper side and/or lower side of the magnetic layer 2. The max. particle size of the material for forming the carbon layer of the layer (carbon layer) substantially consisting of the carbon is further preferably <=0.02mm. On the other hand, the max. particle size is preferably >=0.03mm in terms of the cost and yield of producing a target. This carbon layer may be formed as a protective layer 3 on the surface of the thin film magnetic layer 2 on a nonmagnetic substrate 1 or may be further formed as an underlying layer 4 under the magnetic layer 2. In either case, the carbon layer can be provided in at least one layer on the substrate as the protective layer or underlying layer having 0.01-0.5mum thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to magnetic recording media such as magnetic disks and magnetic tapes, and methods of manufacturing the same.

In prior art thin-film magnetic recording media, a common technique is to form a carbon layer as a protective layer (or as an intermediate layer) by a spunter method. A carbon material target is used as the material.

Such targets generally have a maximum particle size of .

It is made of carbon material with a thickness exceeding 0.05 mm (but not more than 0.1 nu++).

However, it has been found that the maximum particle size of conventional target materials is too large, resulting in unstable discharge during film formation, slow film formation speed, and product deterioration and reduced yield.

C.1 Objective of the Invention An object of the present invention is to provide a magnetic recording medium that is stable, has good workability, and has good performance such as durability, and a method for manufacturing the same.

20 Structure of the invention and its effects, that is, the present invention provides that a layer formed of a material having a maximum particle diameter of 0.05 mm or less and consisting essentially of carbon,
This relates to a magnetic recording medium provided above and/or below a magnetic layer.

This magnetic recording medium consists of the above-mentioned layer consisting essentially of carbon (
Hereinafter, it will simply be referred to as a carbon layer. ) has the effect of protecting the surface of the magnetic layer, improving adhesion to the support, etc., and improving the film formability of the upper layer, and also reduces the maximum particle size of the material forming the carbon layer to 0.05IllIl or less. This greatly improves performance such as durability. The maximum particle diameter of the carbon layer forming material is preferably 0.02 mm or less.

On the other hand, in view of target manufacturing cost and yield, the maximum particle diameter is preferably 0.003 mm or more. Further, this carbon layer may be formed as a protective layer 3 on the surface of the thin magnetic N2 on the non-magnetic support 1, as shown in FIGS. 4 may be formed. In any case, at least one carbon layer can be provided on the support as a protective layer or base layer with a layer thickness of 0.01 to 0.5 μm. In the case of the base layer, the film formability of the upper layer can be well controlled, and the processing cost can be reduced because the support does not have to be processed much in advance.

Here, as the above-mentioned support 1, plastics such as Al, Al with an anodized coating (for example, alumite treatment), Al with N1-P plating treatment, polyimide, polyaramid, polycarbonate, etc. can be used. The support 1 may have various shapes such as a plate shape or a film shape.

Moreover, as the above magnetic N2, Co-Ni XCo
-Ni-Fe.

Co-Ni-Cr% Co-Cr% T-F
A known thin film magnetic layer such as ezoz or Ba ferrite may be used, and the layer thickness may be 0.03 to 0.6 μm. The thickness of the magnetic layer is preferably 0.03 to 0.2 .mu.m5 suitable for in-plane recording, and 0.08 to 0.6 .mu.m suitable for perpendicular recording. The magnetic layer 2 can be formed by a known method such as a sputtering method or a vacuum evaporation method.

Further, in forming the carbon layer, the present invention performs sputtering using a material substantially consisting of carbon having a maximum particle size of 0.05 mm or less as a target material, thereby forming a layer corresponding to the target material. The upper side of the magnetic layer and/or
Also provided below is a method for manufacturing a magnetic recording medium formed in (!1.1+).

That is, according to this manufacturing method, since a material having a maximum particle diameter of 0.05 mm or less and consisting essentially of carbon (hereinafter simply referred to as carbon material) is used as the target material, the maximum particle diameter By making it smaller than conventional products, the discharge during sputtering becomes stable, and it is possible to improve the film forming speed and yield. The maximum particle diameter of the carbon material (target material) used is preferably 0.02 mm or less.

In addition, in the present invention, the above-mentioned "maximum particle diameter" means the largest long axis diameter of particles measured by microscopic observation.

Although the manufacturing method of the present invention is based on a sputtering method, it may be formed by a facing target sputtering method as shown in FIG.

That is, in FIG. 3, 11 is a vacuum chamber, and 12 is a vacuum chamber 1.
1 is an exhaust system consisting of a vacuum pump, etc. for evacuating 1;
This is a gas introduction system set at approximately 0-'Torr. The target electrodes are configured as opposed target electrodes in which a pair of targets TI and Tz are separated from each other by a target holder 14 and arranged to face each other in parallel. A magnetic field is generated between these targets by magnetic field generating means (not shown).

In the sputtering apparatus configured in this way, a magnetic field is formed in a direction perpendicular to each surface of both targets 1-TIST2 that face each other in parallel, and this magnetic field causes the cathode fall portions (i.e., Kugetl-T, -T The γ electrons emitted by the impact of the sputtering gas ions accelerated by the electric field between the plasma atmosphere generated between , and the region between T + and T2) on the target surface are trapped in the space between the targets. , move toward the other opposing target. The γ electrons that have moved to the other target surface are reflected at the cathode fall section nearby. In this way, the γ electrons repeatedly move back and forth between the targets 'rt-'rz while being constrained by the magnetic field. During this reciprocating motion, the γ electrons collide with the neutral atmospheric gas to generate ions and electrons of the atmospheric gas, and these products promote the release of γ electrons from the target and the ionization of the atmospheric gas. . Therefore, a high-density plasma is formed in the space between the targets T + Tz, and the target material is sputtered sufficiently and deposited on the substrate 1 on the side.

Compared to other flying methods, this facing target sputtering device enables film formation at a high deposition rate through high-speed sputtering, and the substrate is not directly exposed to plasma, allowing film formation at low substrate temperatures. This is advantageous because it is possible. Moreover, since the incident energy of the film material ejected by the opposed target sputtering device onto the substrate is smaller than that of a normal sputtering device, the material is easily deposited directionally in a desired direction. In addition, even if the film is formed by the magnetron spa/vine method, the same effect can be obtained.

E, Example Examples of the present invention will be described in detail below.

Target for moxibustion base: Graphite target made by Poco (maximum particle size: 0.05 mm) Ultimate vacuum: 5 x 10-' Torr or less Ar
Gas pressure 3. OX 10-'Torr input power 3,5 W/crA carbon layer thickness
Under sputtering conditions of 0.03 μm or more, a predetermined amount of G, for example.

An attempt was made to form a carbon layer by sputtering on the -Ni thin film recording magnetic layer. The results are shown in Table-1.

Table-1 Amount of abnormal discharge during film formation (excluding 60 minutes of preliminary discharge).

)Average 0.4 times/min Film forming speed 0.05 μm/min Protective film surface roughness Rz =0.008 pm After film forming, protective layer durability test (CS S (ContactS
tart and top) test], there was no change at all even after 10,000 times or more.

Target material using comparison plate Comparison product Graphite target (
Maximum particle size: 0.06mm) Ultimate vacuum: 5 x 1O-bTorr or less Ar
Gas pressure 3. OX 10-'' Torr Input power 3.5 W/cJ Carbon layer thickness 0.03 μm A carbon layer was formed on the Co-Ni 1 recording magnetic layer under the condition of 0.03 μm or more. I tried.

The results are shown in Table-2.

Table-2 Amount of abnormal discharge during film formation (excluding 60 minutes of preliminary discharge).

)Average 1.3 times/min Film forming speed 0.03 μm/min Protective film surface roughness RZ = 0.014 μm After film forming, a protective layer durability test (CSS test) was conducted and 400
After 0 cycles, scratches were generated on the protective film due to running.

As is clear from the Examples and Comparative Examples, in the Examples, although the films were formed under the same conditions as in the Comparative Examples, the abnormal discharge decreased, the film forming speed increased, and the surface roughness of the protective film decreased. Diminished. As a result, durability was improved and satisfactory durability was obtained. The maximum particle diameter of the target should be 0.05n+m or less (and the maximum particle diameter should be 0.05n+m or less).
When a graphite target of 02n+n+ was used, more satisfactory durability was obtained, and the number of abnormal discharge occurrences was reduced.
The film forming speed, surface roughness, etc. were also similar.

Target material used: Poco graphite target (Large particle size: 0.02mm) Ultimate vacuum: 5 x 10-'Torr or less Ar
Gas pressure 3. Ox 10-'Torr input power 3.5W/co! A predetermined amount of carbon, for example, is applied under sputtering conditions such that the carbon layer thickness is 0.03 μm or more.

An attempt was made to form a carbon layer by sputtering on the -Ni thin film recording magnetic layer. The results are described below.

Number of occurrences of abnormal discharge Average 0.3 times/min Film forming speed
0.05μm/min Protective film surface roughness Rz =
After 0.008 pm film formation, a C3S test was conducted and no change was observed after 10,000 cycles.

Target used for moxibustion by JLfL Graphite target manufactured by Poco (Q large particle diameter 0.05 mm) Ultimate vacuum 5 x 10-6 Torr or less A
Gas pressure 3. A magnetic disk having a layer structure as shown in FIG. 2 was manufactured under sputtering conditions of OX 10-' Torr input power 3.5 W/cd or more. Here, the thickness of the underlying carbon layer is 0.1 μm, and the thickness of the protective layer is 0.03 μm.

As a result of the durability test (C3S test), 10,00
There was no change after 0 times.

From the above results, it is clear that the maximum particle size depends on the film forming process, film quality,
This has a large effect on durability, and it is understood that it is extremely important to keep the maximum particle diameter of the target material and the maximum particle diameter of the obtained carbon layer to 0.05+n+a or less based on the present invention.

[Brief explanation of drawings]

The drawings illustrate the invention and include FIGS. 1 and 2.
Each figure is a cross-sectional view of a magnetic recording medium, and FIG. 3 is a schematic cross-sectional view of a facing target sputtering apparatus. In addition, in the symbols shown in the drawings, 1-.
・−・・−・−Magnetic layer 3−・−・・−・−−−−−・Carbon layer (protective layer) 4−・
・−・−・−Carbon N (base layer) 11−・−・−−−
−−・・・・Vacuum chamber 12−・−・−・・・・Exhaust system +3−−・−−−−−・−・・Gas introduction system T + , T
z −−−−−−−−−−−−...Target.

Claims (1)

[Claims] 1. A magnetic recording medium in which a layer formed of a material substantially consisting of carbon and having a maximum particle diameter of 0.05 mm or less is provided above and/or below a magnetic layer. . 2. By performing sputtering using a material substantially consisting of carbon having a maximum particle size of 0.05 mm or less as a target material, a layer corresponding to the target material is formed above and/or below the magnetic layer. A method for manufacturing a magnetic recording medium.