JPH0334116A - Magnetic recording medium and production thereof - Google Patents

Abstract

PURPOSE:To form the medium with good controllability by irradiating a raw material layer with an ion beam having an element to combine with a semiconductor, etc., to induce a chemical reaction within the raw material, thereby locally forming the compd. consisting of the semiconductor, etc., and the irradiating ions in the region irradiated with the ion beam on a nonmagnetic underlying layer, etc. CONSTITUTION:The raw material layer on the surface of the substrate 1 with the nonmagnetic underlying layer constituted by forming the raw material contg. the semiconductor or metal element on the substrate in a hydrogen bond or Van der Waals bond state or the protective layer thereof is irradiated with the ion beam 4 contg. the element having the property to combine with the semiconductor or metal material. As a result, the chemical reaction is induced in the raw material. The compd. consisting of the semiconductor or the metal element thereof and the irradiating ion elements is locally formed in the region irradiated with the ion beam on the nonmagnetic underlying layer or the protective layer. The texture structural material in a dry atmosphere is formed with the good controllability in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording medium and a method for manufacturing the same;
In particular, the present invention relates to a magnetic recording medium used in a magnetic recording device and a method for manufacturing the same.

[Prior Art] In recent years, the importance of magnetic disks as external storage devices in computer systems has increased, and the storage density thereof has been significantly improved year by year. Conventionally, magnetic recording media are
Development has been focused on the thinning of coated media in which a viscous material in which acicular γ-FezOs fine particles are dispersed in an organic binder is spin-coated onto an aluminum alloy substrate and then fired, and is currently widely used. However, in order to achieve higher storage density, it is necessary to make the media thinner, but current coated media are considered to have technical limitations, and as an alternative high-density magnetic disk, Magnetic disks with metal magnetic thin film media that can be easily made thin are attracting attention. These metal magnetic thin film media include plated magnetic disks formed by plating technology, metal magnetic films (Go-Cr, Co-Ni, etc.), or sputter disks using metal oxide magnetic films (γ-Fe20a, etc.). It is expected that the recording density will be significantly increased.

The general structure of a magnetic disk using such a thin film continuous medium is shown below. That is, a high-purity aluminum alloy is used for the substrate, and a nonmagnetic underlayer is formed thereon. A magnetic layer is formed on the underlayer, but an intermediate layer may be formed between these two layers for the purpose of improving the adhesion between the two layers and the magnetic properties of the magnetic layer. A protective layer and a lubricating layer are formed on the magnetic layer.

This underlayer is required to have flatness and smoothness in order to enable the magnetic layer to be thinned, to ensure a stable head flying state at a low flying height, and to significantly reduce substrate defects. In addition, the base layer has mechanical strength, workability,
In addition to various properties such as polishability, for example, JP-A-59-4
As disclosed in Japanese Patent No. 5634, it is required that the underlayer is not magnetized even by heat treatment during the formation process of the magnetic layer, protective layer, or lubricating layer.

Current disk devices use C, S S (Contact
5tartStop) method is adopted, and when the device is stopped, the magnetic head and disk are in contact with each other, but when the device starts up.

When stopped, it runs in contact, and when it is stationary, it runs through a gas film,
Drive without contact. For this reason, it is important to prevent the magnetic head from adhering to the disk surface when it is stopped, and to reduce the frictional force when starting and stopping. Conventionally, fine grooves called textures have been formed on the surface of the underlayer. has been done. An N1-P film formed by an electroless plating method is generally used as the base layer, and a method of forming the texture using abrasive grains and tape on the surface of the N1-P film is widely used.

After forming the texture, washing with a large amount of pure water and drying, an intermediate layer, a magnetic layer, and a protective layer are formed using a vacuum reactor.

[Problem to be solved by the invention]

The above-mentioned prior art has a non-magnetic underlayer on the substrate, for example, N1.
- After forming the P plating layer, the surface of the plating layer is created using a physical processing method using abrasive grains and tape, so it is necessary to wash and remove the abrasive powder adhering to the surface. It uses water.

Therefore, there are problems in that the processing time is long and the cost is also very high. Furthermore, while the magnetic layer is generally formed in a vacuum reactor, this pretreatment is performed in the atmosphere, which poses the problem of complicating the overall manufacturing process of the magnetic recording medium. there were.

An object of the present invention is to provide a magnetic recording medium that has a small coefficient of friction between a magnetic head and a magnetic recording medium, and has excellent sliding resistance.
and to provide an efficient manufacturing method thereof.

[Means to solve the problem]

The above purpose is to apply a raw material containing a semiconductor or a metal element to the surface of a non-magnetic underlayer or a protective layer formed on a substrate in a hydrogen bond or Van der Waals bond state. The source material layer is irradiated with an ion beam containing an element that has the property of combining with a substance, causing a chemical reaction within the source material to form a compound consisting of the semiconductor or the metal element and the irradiated ion element.

This can be achieved by locally forming the ion beam irradiation area on the non-magnetic underlayer or the protective layer.

[Effect]

FIG. 2 schematically shows a method of locally depositing a silicon dioxide oxide film 2 on a substrate 1 on which a nonmagnetic base film is formed. An oxygen ion beam 4 with an ion beam diameter of 50 μm is irradiated to a solidified material 3 of monosilane gas with a thickness of 100 μm in a Van der Waals bond state at an acceleration energy of 5 keV, and chemical reaction occurs within the solidified material 3 irradiated with the ion beam 4. By causing a reaction, silicon dioxide 2, which is a compound of silicon element and oxygen element, can be locally deposited.

〔Example〕

<Example 1> An Af substrate with a diameter of 5.25 inches was used as a substrate for a magnetic recording medium.
1 alloy (containing about 4 wt% Mgv), a 12 μm Ni-P film was applied to this substrate by the usual electroless plating method.
After forming the N1-P film, a substrate 1 with a N1-P film having a surface roughness Ra (center line average roughness) of 5 nm and a film thickness of 10 μm was obtained by polishing. As shown in Figure 1.

It is transported into a vacuum container 6 equipped with a refrigerator 5, and the temperature is lowered to -20°C.
It was fixed on a disc-shaped cooling head 7 with a diameter of 200 mm that was maintained at 0°C.

While maintaining the temperature of the N1-P film coated substrate 1 at -190°C and rotating the cooling head 7 at a rotation speed of 1 Orpm, monosilane gas (melting point -185°C) 3 was applied.

The gas was supplied from the gas blowing pipe 8 at an inflow rate of 1cc/min for 10 minutes to form a solidified monosilane gas 3 having a film thickness of 5 μm on the surface of the substrate 1.

Next, an oxygen ion beam 4 of 50 ke is emitted from the ion source 9.
It was extracted with an acceleration energy of V, and the solidified N3 of monosilane gas was irradiated as shown in FIG.

The current density of the oxygen ion beam 4 at that time is lOμA/
At, the size of the irradiation area of ion beam 4 is 10 μm
It was the diameter.

As a result, a chemical reaction between silicon and oxygen occurred inside the solidified layer 3 of monosilane gas irradiated with the ion beam 4, and silicon dioxide 9 was formed. The cooling head 7 was rotated at a rotational speed of 1100 rpm, and the solidified layer 3 of monosilane gas was irradiated with the oxygen ion beam 4 intermittently while moving in the radial direction. As a result, the silicon dioxide 2 was placed on the N1-P film coated substrate 1 with a diameter of about 10 μm and a height of 10-
It was possible to form convex portions of 20 nm in concentric circles at a pitch of about 5 μm over the entire surface. Next, when the temperature of the substrate was returned to room temperature, the solidified layer 3 of monosilane gas that had been formed in the portions not irradiated with the oxygen ion beam evaporated and disappeared. The evaporated monosilane gas was then exhausted by a vacuum pump.

As shown in FIG.
(not shown) and continuously transport the intermediate layer (Cr) 11.
Magnetic layer (Co-Ni-Cr) 12 and protective layer (C)
13 was formed. The pressure during sputtering is argon pressure 5
mTorr, DC output of 2 kW, and the thickness of each layer was 0.2 μm.

50 nm and 50 nm. After this step, a liquid lubricant was applied to manufacture the magnetic recording medium 14.

Using the magnetic recording medium 14, a 10 gf load was applied to the sapphire spherical slider and a sliding test was performed at a linear velocity of 10 m/s. As a result, the friction coefficient was 0.15 or less, and the friction coefficient was also There was almost no increase after the test, and it was found that the magnetic recording medium had excellent sliding resistance.

Furthermore, the sliding property of the recording medium is M n
A normal C8S test was performed using a -Zn ferrite head, and no flaws were observed on the surface of the magnetic recording medium even after approximately 30,000 C8S tests.

As mentioned above, the magnetic recording medium formed in this example has N
The sliding resistance was comparable to that of conventional recording media in which a magnetic layer was formed after forming a texture on the 1-P film by processing with abrasive grains and tape.

Furthermore, unlike conventional methods, Honjitsu's texture processing method does not require washing with pure water after processing, and the shape of the texture can be controlled and processed, resulting in good yields and easy quality control. It's easy.

<Example 2> As in Example 1, a substrate of a magnetic recording medium with a diameter of 5.5mm was used.
25 inch Af1 alloy (contains about 4 wt% M g )
Ni-
After forming a P film with a thickness of 12 μm, polishing was performed to improve the surface roughness R.
a (center line average roughness) 5 nm, film thickness 10 μm N1-
A substrate with a P film was obtained, and as shown in FIG. 1, it was transported into a vacuum container 6 equipped with a refrigerator 5 and fixed on a disk-shaped cooling head 7 with a diameter of 200 mm whose temperature was maintained at -55°C. did.

While maintaining the temperature of the N1-P film coated substrate 1 at 0°C and rotating the cooling head 7 at a rotational speed of 1 Orpm, trimethylaluminum gas ((CHs)3AQ, melting point 15.2°C) was heated.
was supplied from the gas outlet 8 at an inflow rate of 1 cc/win for 10 minutes to form a solidified trimethylaluminum gas having a film thickness of 5 μm on the surface of the substrate 1.

Next, the oxygen ion beam 4 is emitted from the ion source 9 at 3 ke
It was extracted with an acceleration energy of V, and the solidified layer of trimethylaluminum gas was irradiated as shown in FIG. The current density of the oxygen ion beam 4 at that time was 10 μA/−, and the size of the irradiation area of the ion beam 4 was 10 μm in diameter.

As a result, a chemical reaction between aluminum and oxygen occurred inside the solidified layer of trimethylaluminum gas irradiated with the ion beam 4, and aluminum oxide was formed.

Carbon and hydrogen elements contained in trimethylaluminum became carbon oxide and water, respectively, and were evacuated. As in the previous embodiment, the cooling head 7 is rotated at a rotational speed of 1
The solidified layer of 5 trimethylaluminum gas was irradiated with the oxygen ion beam 4 intermittently while rotating at rpm and moving in the radial direction. As a result, the N1-P film coated substrate 1
Approximately 10 μm in diameter and 10 2 in height of aluminum oxide on top
It was possible to form convex portions of 0 nm in concentric circles at a pitch of about 5 μm over the entire surface.

The substrate 1 is transferred into a DC two-pole sputtering device (not shown), and an intermediate layer (Cr) 11. Magnetic layer (Co-Ni-
Cr) 12 and a protective layer (C) 13 were formed. The pressure during sputtering was argon pressure 5 mTorr, D
At a C output of 2 kW, the thickness of each layer is 0.2
They were μm, 50 nm, and 50 nm. After this step, a liquid lubricant was applied to manufacture the magnetic recording medium 14.

Using the magnetic recording medium 14, a 10 gf load was applied to the sapphire spherical slider and a sliding test was performed at a linear velocity of 10 m/s. As a result, the friction coefficient was 0.15 or less, and the friction coefficient was also There was almost no increase after the test, and it was found that the magnetic recording medium had excellent sliding resistance.

Furthermore, M n
A normal C8S test was performed using a -Zn ferrite head, and no flaws were observed on the surface of the magnetic recording medium even after approximately 30,000 C8S tests.

As described above, the magnetic recording medium formed in this example has an N1
The sliding resistance was comparable to that of conventional recording media in which a magnetic layer was formed after forming a texture on the -P film using abrasive grains and tape.

<Example 3> Instead of monosilane gas and trimethylaluminum gas in Examples 1 and 2, titanium tetrachloride (T i CQ
a, melting point -25°C) is formed on the surface of the substrate 1, and using the same apparatus and method as in Examples 1 and 2, the solidified layer is irradiated with an oxygen ion beam 4 to form titanium oxide (TiO2). It was possible to form convex portions on the entire surface of the substrate 1 in concentric circles with a pitch of about 5 μm. Intermediate 1 (Cr) 11.
After forming the magnetic layer (Co-NiCr) 12 and the protective layer (C) 13, a liquid lubricant was applied to manufacture the magnetic recording medium 14.

This magnetic recording medium 14 is also a magnetic recording medium with excellent sliding resistance, and its sliding resistance is comparable to that of conventional recording media.

<Example 4> The underlayer of the magnetic recording medium is not limited to the N1-P film, and nonmagnetic materials such as metal nitride, carbide, oxide, and boride films can also be used. .

AQ alloy with a diameter of 5.25 inches was used as the substrate,
A high frequency output of 2 was generated in Ar + Nz using a metal Ti as a target on the substrate using the magnetron superstructure method.
kW to form a 2 μm TiN film. A minute convex portion of 5 iOz was formed on the substrate 1 in the same manner as in Example 1, and a magnetic layer and the like were formed to produce a magnetic recording medium. The sliding resistance of the magnetic recording medium prepared in this example was evaluated in the same manner as in Example 1, and it was found that the magnetic recording medium had substantially the same performance.

<Example 5> A 3.5-inch diameter substrate was used as a substrate for a magnetic recording medium.
Using the Q alloy base substrate 2, an N1-P film 21 with a thickness of 12 μm was formed on the substrate 20 by an electroless plating method, and the surface was polished to obtain a N1-P film thickness of 10 μm and a surface roughness ( R
A4 nm) substrate was created.

An intermediate layer 11 (Cr) was formed on this substrate under the same conditions as in Example 1.
, magnetic layer 12 (Go-Ni-Cr), and protective layer 13
(C) was formed by sputtering. The thickness of each layer was 0.25 μm, 40 nm, and 50 nm, respectively.

Using the same device as in Example 1, using the substrate on which each of these layers was formed, a convex shape of silicon dioxide 2 was formed on the protective film 13.
was formed.

The shape of the convex portion of silicon dioxide formed in this example is as follows:
The particles had a diameter of about 10 μm and a height of 10 nm or less, and were formed so as to be uniformly distributed within the warp surface.

The convex portions may be formed, for example, at regular pitches in the circumferential direction of the disk, or may be randomly distributed on the disk surface.

Approximately 50% of liquid lubricant was applied onto this disk by spin code
A magnetic recording medium was formed by coating with a film thickness of nm.

10 on a sapphire spherical slider using a magnetic recording medium.
As a result of applying a gf load and performing a sliding test under the conditions of a linear velocity of 10 m/s, the friction coefficient was approximately 0.2 or less, and this value remained approximately the same even after approximately one-way measurement. Ta. Furthermore, using an AQzOa TiC-based magnetic head, C8
As a result of conducting the S test, no scratches were observed on the surface of the magnetic recording medium even after the CSS test from about three sides, and it was found that the magnetic recording medium had excellent sliding resistance.

<Example 6> Similar to the actual stripping, a substrate with a diameter of 5 mm was used as a substrate for a magnetic recording medium.
25 inch AQ alloy (contains about 4wt% M g y)
20, and the substrate 20 is coated with N by the usual electroless plating method.
After forming a 1-P film with a thickness of 12 μm, it was polished to a surface roughness Ra (center line average roughness) of 5 nm and a film thickness of 10 μm.
An intermediate layer 11 (Cr), a magnetic J112 (Co-Ni-Cr), and a protective layer were formed on it under the same conditions as in Example 1, as shown in FIG. 13(C)
was formed by sputtering. The thickness of each layer is 0.
They were 25 μm, 410 nm, and 50 nm.

As shown in the construction drawing, the substrate on which each layer has been formed is transported into a vacuum container 6 equipped with a refrigerator 5 and fixed on a disk-shaped cooling head 7 with a diameter of 200 na kept at a temperature of -55°C. did.

While maintaining the temperature of the N1-P film coated substrate at -100°C and rotating the cooling head 7 at a rotational speed of 1 Orpm, silicon tetrachloride gas (S i CQ4,
(melting point -70° C.) was supplied for 10 minutes at an inflow rate of O, lee/ffl1n, to uniformly form a solidified silicon tetrachloride gas 21 with a film thickness of 1 μm on the surface of the protective layer 13.

Next, an oxygen ion beam 4 is generated with an acceleration energy of 5 keV from a focused ion beam generator 9 connected to the vacuum container 3.
was scanned and irradiated onto the surface of the protective layer in a two-dimensional manner.

The current density distribution of the focused oxygen ion beam is shown in Figure 5(a).
102A in a region with a diameter of 50 nm at the center as shown in
/ln, 50μA/ln in a 300nm diameter area around it.
(It was 1#.) The ion beam irradiation time per location was 1/100 second.

In the area irradiated with the focused oxygen ion beam, a chemical reaction occurred between silicon tetrachloride gas (SiCQi) and the ion-implanted oxygen element (○), and a silicon dioxide oxide film (SiO2) was formed.

The film thickness distribution is as shown in Figure 5(b), with a diameter of 50 mm.
The convex region had a height of 10 nm in the central region of 10 nm, and the region outside the central region with a height of 2 nm or less had a diameter of 50 μm.

By changing the voltage applied to the ion beam scanning electrode 22,
By controlling the scanning position of the ion beam 4 in a pulsed manner while rotating the disc-shaped cooling head 7 at a rotational speed of 1 rpm, the convex portions are formed in a spiral pattern over the entire surface of the protective layer 13 at intervals of approximately 5 μm. Formed.

By controlling the scanning method of the focused ion beam, the convex portions may be formed at regular pitches in the circumferential direction of the disk, or they may be formed on the disk surface at irregular or random pitches. It does not matter if it is distributed as follows.

Approximately 50% of liquid lubricant was applied onto this disk by spin code
A magnetic recording medium was formed by coating with a film thickness of nm.

10 on a sapphire spherical slider using a magnetic recording medium.
As a result of applying a gf load and performing a sliding test under the conditions of a linear velocity of 10 m/s, the friction coefficient was approximately 0.2 or less, and this value remained approximately the same even after the measurements in the figure. Ta. Furthermore, using an AnzOs TiC magnetic head, C8
As a result of conducting the S test, no scratches were observed on the surface of the magnetic recording medium even after the CSS test on about three sides, and it was found that the magnetic recording medium had excellent sliding resistance.

Example 7 In Example 5, the protective film of the magnetic recording medium was made of carbon formed by sputtering, but the present invention is not limited thereto. Plasma CVD method when carbon is used as the protective film material.

Even with a hard carbon film formed by ion beam sputtering, photo-CVD, etc., convex portions similar to those in the embodiment can be formed on the surface.

Furthermore, the protective film material is not limited to carbon;
A metal or semiconductor nitride, carbide, oxide, or boride film may be used.

Furthermore, the material for forming the convex portions on the protective film shown in Example 5 is not limited to silicon dioxide, and
Similar effects can be obtained with oxides such as Q and Ti.

In addition, as shown in Example 5, after forming the convex portions of the silicon dioxide film on the protective film, abnormal convex portions (higher than average convex portions) on the surface were removed by burnishing with tape or the like or with an ion beam shower. A magnetic recording medium may be formed by applying a liquid lubricant after scraping off the magnetic recording medium.

〔Effect of the invention〕

According to the present invention, a texture structure material can be formed with good controllability in a dry atmosphere. Furthermore, since the thickness distribution of the texture structure material is exactly proportional to the intensity distribution of the ion beam, a texture structure with rounded corners can be easily created.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the basic principle of the invention, Fig. 3 is a sectional view of a magnetic recording medium, and Fig. 4 is a convex shape on the magnetic recording medium. An explanatory diagram for forming an object, FIG. 5(a) is a current density distribution diagram of a focused ion beam, and FIG. 5(b) is a film thickness distribution diagram of formed silicon dioxide. 1...Substrate with non-magnetic base film, 2...Silicon dioxide. 3... Monosilane gas, 4... Oxygen ion beam,
5... Refrigerator, 6... Vacuum container, 7... Disc-shaped cooling head, 8... Gas outlet tube, 9... Ion source, 22... Io diagram, Figure 2, Figure 4 Figure Figure -150-100-50050100f50.71□Middle Bi

Claims (1)

[Claims] 1. A method for manufacturing a magnetic recording medium, in which a nonmagnetic underlayer is formed on a substrate, and then a magnetic layer and a protective layer are formed on the nonmagnetic underlayer, comprising: After forming a compound containing a semiconductor or a metal element on a geological layer in a hydrogen bond or Van der Waals bond state, an ion beam containing an element that has the property of combining with the semiconductor or metal is irradiated to remove the hydrogen bond. Alternatively, a chemical reaction is caused within the Van der Waals bond state material, and a compound of the semiconductor or the metal element and the irradiated ion element is locally deposited on the ion beam irradiation area, and then the compound is deposited on the deposited layer. . A method of manufacturing a magnetic recording medium, characterized in that the magnetic layer and the protective layer are formed. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein the non-magnetic underlayer, the magnetic layer, and the protective layer are formed on the substrate, and the semiconductor or the metal element is further formed on the substrate. After a compound is formed in the hydrogen bond or van der Waals bond state, an ion beam containing an element that has the property of combining with the semiconductor or metal is irradiated to form a chemical compound in the hydrogen bond or van der Waals bond state. A method for manufacturing a magnetic recording medium, characterized in that a reaction is caused and a compound of the semiconductor or metal element and the irradiated ion element is locally attached to the ion beam irradiation area. 3. A method for producing a hydrogen bond or a Van der Waals bond state in the semiconductor or a compound containing the metal element according to claims 1 and 2, wherein the semiconductor or the compound containing the metal element is liquid at room temperature and pressure; Alternatively, a method for manufacturing a magnetic recording medium characterized by forming a layer made of a gaseous substance solidified in a vacuum. 4. A magnetic compound characterized in that the compound formed by the ion beam according to claim 1 or 2 is formed on one side or both sides of the substrate in a concentric or spiral shape. A method for manufacturing a recording medium. 5. A method for manufacturing a magnetic recording medium according to claim 2, 3 or 4, characterized in that an ion beam containing oxygen, nitrogen, carbon, and boron elements is used. 6. A method for manufacturing a magnetic recording medium according to claim 1, 2, 3, 4 or 5, characterized in that a focused ion beam is used. 7. A magnetic recording device and a magneto-optical recording device incorporating the magnetic recording medium according to claim 1 or 2.