JPH0447527A - Production of magnetic recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic recording medium in which Cr and Cjo alloy thin films are sequentially laminated on a non-magnetic base material.

[Conventional technology]

Conventionally, magnetic recording media have been produced by depositing acicular particles such as iron oxide or ultrafine powder of ferromagnetic alloy in a resin binder on an A/-MP substrate with a hardened base layer such as NLP or directly on an A/-MP substrate. The magnetic recording layer was formed by dispersing it into a magnetic recording layer. However, due to the recent demand for high-density recording of information, wet plating, vacuum deposition,
Magnetic recording media whose magnetic recording layer is a ferromagnetic thin film layer formed by thin film formation methods such as sputtering and ion blating are being actively researched and developed. It is excellent in high-density recording and mass production, and is considered to be the main magnetic recording medium of the future.

By the way, magnetic recording media (hereinafter referred to as metal sputtering media) produced by this sputtering method are generally manufactured by sequentially forming Cr and C70 alloy thin films on an A/-MP substrate with a hardened N1-P base layer. It can be obtained by Loading chamber/bar, J[2[thermal chamber]
, Cr cathode.

The Cr thin film layer is produced by an in-line sputtering apparatus consisting of a sputter chamber with a CO alloy cand and a protective film cathode as well as an A-day/guchi chamber.

The method for forming the Co alloy thin film layer and the protective film layer is as follows:
There are two types: a passing type, in which the substrate passes in front of each target, and a stationary facing type, in which the substrate remains stationary in front of each target. In either type, the procedure for producing a metal sputtering medium is the same.

FIG. 8 is a block diagram schematically showing an example of a conventional pass-through type sputtering apparatus. The 4th board is loading chamber Il+ and is true g! After being evacuated, the substrate is transported to a substrate heating chamber 121 and heated to a predetermined temperature. Next, it is transported to a sputtering chamber 3; where a Cr thin film layer, C
The o-alloy thin film layer and the protective film layer are sequentially formed, and finally the material is transported to the unloading chamber (4) and returned to the atmosphere.

In Figure 1, +51 is the heater and (6) is the Cr target.

17) is CO alloy turf, f8) i protective film material target, +911d partition pulp.

By the way, the magnetic properties and electromagnetic conversion properties of this metal sputtering medium strongly depend on the conditions (substrate temperature, sputtering gas pressure, etc.) when forming the Cr thin film layer and the Co alloy thin film layer, and it is important to consider the influence of the substrate temperature. As reported in 1988 IEICE Study Group Report MR88-2, increasing the substrate temperature improves the magnetic properties (
In particular, the coercive force) is improved and the reproduced signal becomes larger during high-density recording, but media noise also increases, so s/
As far as the N ratio (signal strength to noise ratio) is concerned, it is 0M.
There is a problem in that the improvement expected from the same characteristics as above is not observed.

It is known that this media noise has a close relationship with the crystal grain size of the 00 alloy thin film that is the magnetic recording layer, and that the crystal grain size of the FCCO alloy thin film has a close relationship with the crystal grain size of the underlying Cr layer. . Tsu1su, O.

Does the alloy thin film grow evixically on the 01 layer? In order to
Grain size of Co alloy thin film? In order to control this, it is necessary to control the crystal grain size of the Cr layer. The reason why the medium noise increases when the substrate temperature is raised is considered to be because the crystal grain size of Cr increases, and as a result, the crystal grain size of the co alloy thin film also increases.

[Problem to be solved by the invention]

As described above, in the conventional method of manufacturing a magnetic recording medium using the sputtering method, it is necessary to raise the substrate temperature when forming the KM recording layer in order to improve the 5a characteristics. However.

At the same time, it also increases media noise! 4! There was a problem.

This invention was made to solve the above-mentioned problems, and it is possible to improve the feel, improve the reproduction output during high-density recording, reduce media noise, and improve the 8/N
An object of the present invention is to provide a method for manufacturing a magnetic recording medium that can improve the ratio.

[Means to solve the problem]

The method for manufacturing a magnetic recording medium of the present invention includes applying C to a non-magnetic base material.
A magnetic recording medium is formed by sequentially laminating an r thin film and a 00 alloy thin film, and the Cr thin film has a two-layer structure, and the base material temperature is ? After forming the Cr thin film, the temperature of the base material is 1ft150℃ or higher.
The second Cr thin film and the 00 alloy thin film are formed in this order by applying the following process.

[Effect]

The method for manufacturing a magnetic recording medium according to the present invention includes a first Cr
By forming the thin film at a low temperature, the crystal grain size of the Cr thin film is reduced, and the second Cr thin film and 00 alloy thin film are formed at a higher substrate temperature. The crystal grain size can be made smaller than that formed directly on the N1-P underlayer, and the crystal grain size of the co alloy R film formed thereon can be made smaller, and the magnetic properties can be improved. Therefore, the reproduction output during high-density recording of the magnetic recording medium can be increased to the same level as above, and the medium noise can be lowered.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a magnetic recording medium according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an outline of an in-line sputtering apparatus according to an IM array of the present invention.

In the figure, +lIr1 loading chamber, 1z1 is base rod heating chamber, 3) sputter chamber 14 is unloading chamber, +51 and +101 n
A-plate heating beater 1 (6) and υυ are Cr targets (7), 00 alloy targets, (8) are protective film material targets, and 191i partition pulp.

After the substrate is magnetized to a vacuum in a loading chamber (11), it is transferred to a substrate heating chamber (Ill K) and heated to a constant temperature (room temperature to 150°C). A thin film is formed.Then, the substrate is further heated to a constant B temperature (150 to soO℃).
A second Cr thin film is formed by heating to a temperature of 100.degree. C., followed by a 00 alloy thin film and a protective film. Thereafter, it is transported to the unrobing warehouse 141 and returned to the atmosphere.

When the film formation temperature of the first Car@ film according to the present invention is increased, the crystal grain size of the Cr thin film to be formed becomes larger, and the second Car film is epitaxially grown on the Cr thin film of @1.
The crystal grain size of the r thin film also increases, and the crystal grain size of the Co alloy thin film epitaxially grown on the second Cr thin film also increases, which increases media noise, so a temperature of 150° C. or less is unreasonable.

In addition, the film formation temperature for the second Cr thin film and Co alloy thin film is 150°C, since the improvement in magnetic properties (especially coercive force) will not be noticeable if the base material temperature is low, and if it is too high, the base material will be damaged.
A range of ~800℃ is suitable, and a range of 200℃~j! 50℃
A more desirable range is O.Next, specific examples will be given and explained.

Implementation column l.

A/ in which a N1-P base hardening layer was provided as a non-magnetic base material
-My Co625 MLs were used as a co alloy with a textured substrate.

Carbon was used as a protective film material for Co Ni Cr having a composition of 01-q and 5at To. Sputtering shown in FIG.

Using a device, the first Cr thin film was heated to 100 OA with the substrate temperature set to room temperature, and then the substrate temperature was raised to 2 soo'c, and the second Cr thin film was deposited at 1000 Å.
A NiCr thin film was formed at a thickness of 50 OA, and a carbon film was further formed at a thickness of 400 Å to form a magnetic recording medium. Note that the sputtering gas pressure at this time was all set to 10 m Torr.

The temperature of the base material at the time of forming the first Cr film is 110°C,
All other film formation was performed under the same conditions as in Example 1 to form a magnetic recording medium.

Comparative example Using the conventional apparatus shown in Fig. 2, Cr thin film, C.

Both NiCr thin films were formed at a substrate temperature of 200° C. to form magnetic recording media.

The other conditions were the same as in column 1.

The magnetic conversion characteristics and magnetic characteristics of the metal sputtering media obtained in Example 1.2 and Comparative Example were measured using a relative velocity ig using a t/Cr1 thin film outlet head.
, 1m/5 recording frequency 8MH5, noise band 20MHz
I went there. In addition, a sample vibrating pear magnetometer (
78M)ft was used.

The results of measuring the magnetic characteristics and magnetic properties are shown in the table.

Table *Columns 1 and 2 both show a slightly lower coercive force than the comparative example, and the reproduction output also shows a slightly lower ICE ft. On the other hand, regarding noise, actual gAJ l and 2 show lower #L than the comparative example, and 2 in S/H.
An improvement of ~8 dB was observed.

In this invention, the crystal grain size of the Co alloy thin film is set to 1iI
The IJ-controlled Cr thin film is made into two layers, the first Cr thin film is formed at a low temperature, the grain size is made small, the second Cr thin film is grown epitaxially on the first Cr thin film at a high temperature,
Even if it is grown, the crystal grain size is formed in a small state, and the second C
The Co alloy thin film epitaxially grown on the r thin film can be formed with a small crystal grain size. C. while keeping the grain size of the beaten %Cr thin film and 00 alloy thin film small.

Since the magnetic properties of the alloy thin film can be improved, an excellent magnetic recording medium that can maintain high reproduction output during high-density recording, reduce noise, and improve %8/N can be obtained.

In addition, in the above example, N1-P was used as the nonmagnetic base material.
A/-M with textured base hardening layer
y substrate, as 00 alloy thin film (!062.5Ni30
C! r? , 5 at % CoNi (!rthin!s) has been described, but the same effect can be achieved by applying it to other substrates or other Co alloy thin films. , sputtering conditions such as sputtering residue pressure are not limited to the above embodiments.

〔Effect of the invention〕

As described above, according to the present invention, in a magnetic recording medium formed by sequentially laminating a Cr thin film and a 00 alloy thin film on a non-magnetic base material, the Cr thin film is two layers and the 10rth thin film is formed at the base material temperature. After forming the film at room temperature or higher and 150°C or lower, the substrate temperature is heated to 4°C or higher and 800°C or lower to form a second C.
Since the r thin film and the Co alloy thin film were formed,
A magnetic recording medium can be obtained in which medium noise can be reduced without impairing magnetic properties and the BlN ratio is the same as above.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an in-line sputtering apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an in-line sputtering apparatus according to a conventional example. In the figure, (31 is a sputtering chamber, (61 and συ are Cr metal, (7) is a CO alloy target, and (101 is a substrate heater.) In each figure, the same reference numerals indicate the same or corresponding parts. shows.

Claims (1)

[Claims] In a magnetic recording medium formed by sequentially laminating a Cr thin film and a Co alloy thin film on a non-magnetic base material, the Cr thin film has a two-layer structure, and the base material temperature is above room temperature and below 150°C, and the first Cr After forming the thin film, the temperature of the substrate was increased to 150°C.
The second Cr thin film and C
A method for manufacturing a magnetic recording medium, characterized in that o-alloy thin films are sequentially formed.