JPS62112250A - Photomagnetic recording element and its production - Google Patents

Abstract

PURPOSE:To form a guide groove comparatively easily even when a glass substrate is used as the disk substrate by forming a metallic thin film on the first main surface side of a magnetic substance film provided with the guide groove having an axis easy for magnetization vertical to the film surface and sticking a glass sheet on the second main surface side by an org. adhesive. CONSTITUTION:The metallic thin film 2 consisting, for example, of Au having excellent corrosion resistance and a dielectric layer 3 consisting, for example, of SiN are formed on the first main surface 11 side of the magnetic substance film 1 provided with a guide groove having an axis easy for magnetization vertical to the surface of a film consisting, for example, of TbCo. Besides, the dielectric layer 4 consisting, for example, of SiN for increasing the Kerr's rotating angle in the actual recording and reproduction is formed on the second main surface 12 side of the magnetic substance film 1. Furthermore, the glass sheet 6 is stuck by the org. adhesive 5 consisting, for example, of an UV curing resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a magneto-optical recording element that records or erases information using thermal energy and reproduces information using interaction between light and magnetism, and a method for manufacturing the same.

[Technical background of the invention and its problems]

In recent years, research and development of optical memory devices that are capable of high density, large capacity, and high speed accessors have been actively conducted in various fields.

Among these, magneto-optical memory devices capable of recording, reproducing, and erasing information are considered to be particularly promising because they can be used as file memories for characters and images, computer memories, and the like.

The recording materials of this magneto-optical memory device include TbCo,
GdCo, TbFe, GdTbFe and Tbty
An amorphous alloy thin film of a rare earth element such as Fe and a transition metal is suitable. This is because the amorphous alloy thin film of rare earths and transition metals has an axis of easy magnetization perpendicular to the film surface, and because it is amorphous, there is no grain boundary noise, and the laser power required for recording can be reduced. This is because it has such excellent properties. However, when an amorphous alloy thin film of rare earth and transition metals is used as a recording material, the Kerr rotation angle due to the magneto-optic effect is 0.2~
The disadvantage is that it is as small as 0.3 degrees, and the quality of the reproduced signal is not good. In order to improve the quality of this reproduced signal, SiO or Si is used on the recording material or between the substrate and the recording material.
Efforts have been made to increase the Kerr rotation angle by forming a dielectric film of n.
cs Vol, 45. No, LA August 1
974, page 3643).

Further, as the disk substrate forming the recording material, inorganic glass plates, organic materials such as acrylic, polycarbonate, and epoxy have been proposed. Guide grooves are essential for disk substrates in order to increase recording density and to perform tracking focusing servo reliably. Organic materials that can be cast or injection molded can be molded using a metal stamper with a guide groove.
Since guide grooves can be formed relatively easily, they are considered to be within close range for practical use. Then, the above-mentioned recording material and a protective dielectric film, or an electric film that increases the Kerr rotation angle, a recording material, and a protective metal film or dielectric film are applied to this organic disk substrate using a multi-source sputtering device. Form in vacuum.

However, in a magneto-optical recording element using such an organic substrate, warping occurs due to stress and moisture absorption with the dielectric film even in a normal atmosphere. This warping deformation poses a major problem in terms of the operating characteristics of recording and reproducing devices. Furthermore, deformation due to rotational force during recording and reproduction cannot be avoided in the case of organic substrates. Furthermore, when placed under high temperature and high humidity conditions (e.g. 70℃R+490%), which is a guideline for long life and reliability, the recording material and dielectric film will peel off from the organic substrate due to hygroscopic expansion due to the large thermal expansion coefficient of the organic substrate. There are things to do. In addition, injection molded acrylic or polycarbonate organic disk substrates suffer from uneven flow and cooling of the injection material.
It has been found that it is unsuitable as a disk substrate for a magneto-optical recording element because it has the disadvantage that the birefringence changes greatly from the center toward the outer periphery. On the other hand, epoxy disk substrates made by casting have small birefringence, but have the drawback of not being mass-producible.

On the other hand, a glass substrate made of an inorganic material has a small coefficient of thermal expansion and does not have the problem of moisture absorption, but it is very troublesome to form guide grooves, and furthermore, manufacturing a disk substrate by polishing is very expensive. In addition, at least one side is optically polished, resist is applied, and exposed using a mask with guide grooves, or after forming guide grooves with resist using an exposure device equipped with a precise feeding mechanism and laser, RIE (reactive ionization) is performed. It is necessary to etch the glass using an etching device to form guide grooves one by one, which has the problem of not being suitable for mass production.

However, on the other hand, since the coefficient of thermal expansion is small and there is no hygroscopicity, a magneto-optical recording element formed by forming a dielectric film that increases the Kerr rotation angle, a recording material, and a dielectric protective film on a glass substrate has the advantage of long life. have.

[Purpose of the invention]

The present invention was made in view of this situation.

The object of the present invention is to provide a magneto-optical recording element in which guide grooves can be formed relatively easily while using a glass substrate as a disk substrate, and a method for manufacturing the same.

[Summary of the invention]

That is, in the present invention, a gold A3 film is formed on the first main side of a magnetic film with a guide groove having an axis of easy magnetization perpendicular to the film surface,
This magneto-optical recording element is characterized in that a glass plate is bonded to the second principal surface side using an organic adhesive.

Furthermore, the present invention is characterized by comprising the steps of bonding the entire culm onto an organic substrate having guide grooves, a glass plate on this magnetic film using an organic adhesive, and the step of peeling off the organic substrate. A magneto-optical recording element and a method for manufacturing the same.

[Embodiments of the invention]

The details of the present invention will be explained below with reference to the drawings.

FIG. 1 is a sectional view showing an example of a partial side surface of the magneto-optical recording element of the present invention. In the figure, on the first main surface (1□) side of the magnetic film (1) with guide grooves having an axis of easy magnetization perpendicular to the film surface made of, for example, TbCo, there is a metal made of, for example, Au, which has excellent corrosion resistance. A thin film (2) and a dielectric layer (2) made of, for example, SiN are formed. In addition, the second main surface (1
On the 2) side, a dielectric layer 0) made of, for example, SiN is formed to increase the Kerr rotation angle during actual recording and reproduction, and furthermore, a dielectric layer 0) made of, for example, UV curable resin (Photo Bond I 1) is formed on the 2) side.
The glass plates (0) are bonded together using an organic adhesive (2) made of Sunrise Meisei KK (00 Sunrise Meisei KK).

Next, an example of a method for manufacturing the magneto-optical recording element shown in FIG. 1 will be explained using FIG. 2. First, as shown in FIG. 2(a), an organic substrate (1
0), a peeling layer (11) of SiO□ is formed by sputtering to a thickness of about 200 mm.

Here, the peeling layer (11) is for easily peeling off the organic substrate (10) later, and is made of metal oxide, metal nitride, semiconductor oxide, or It may be made of semiconductor nitride, etc., and the film thickness is 50 mm.
A range of ~500 people is appropriate. Next, as shown in the same figure (b), Au is formed on the organic substrate (10) continuously with the release layer (11) to a thickness of about 2000 by sputtering, and then Au is further deposited by plating. The metal thin film (2) is completed by forming it to a thickness of about 2 μs.

By using such a procedure, there will be no minute pinholes in the plating process, and the shape of the complete metal protective layer will be unclear, and it is possible to select plating current conditions that will not generate granular structures that can become noise sources. It is. Next, the organic substrate (10) on which the metal thin film (2) has been formed is placed in a vacuum chamber, and after cleaning the surface of the metal thin film (10) by reverse sputtering, as shown in FIG. 1000 dielectric layers■,
A magnetic film (1) about 500 thick and a dielectric layer (a) about 1000 thick are successively formed and taken out into the atmosphere.

Subsequently, as shown in FIG. 2(d), a glass plate 0 is bonded onto the magnetic film 2 using an organic adhesive 2.

This bonding method will now be described in detail with reference to FIG. That is, a glass plate 0 is placed on the ultraviolet light incident window (21) of a vacuum chamber A partitioned by a silicone rubber partition wall (20), and a predetermined amount of organic adhesive (2) is applied. The organic substrate (10), which has a rather large outer circumference, is supported by a deformable Teflon jig (22) so that it can be positioned. In the figure, (23) is a centering jig made of Teflon, and B is a vacuum chamber.

What are the steps for pasting?

■ Evacuate the vacuum chambers of both chambers A and B at the same time to thoroughly degas the organic adhesive (■).

■ Gradually return the vacuum chamber in chamber B to atmospheric pressure and return the organic substrate (10
) and glass plate 0 are pressed together at atmospheric pressure via the silicone rubber partition wall (20).

■ Hold it down for a few minutes to make the organic adhesive (■) thin and uniform.

■ The organic adhesive ■ is cured by irradiating UV light from the ultraviolet incident window (21).

# Return chamber A to atmospheric pressure and take it out.

It is.

Then, as shown in FIG. 2(e), by peeling off the organic substrate (10), a desired magneto-optical recording element is obtained. The method for peeling off the organic substrate (10) is as follows.

It is relatively simple and preferable to utilize the difference in thermal expansion.

That is, by heating the bonded body to 70 to 80°C, the organic substrate (10) is separated with the peeling layer (11) as a boundary.

It can be easily peeled off.

The magneto-optical recording element shown in Fig. 1 uses a glass plate 0 with a low coefficient of thermal expansion and no hygroscopic expansion as the substantial main supporting substrate. The expansion and contraction of the magnetic film (2), the metal thin film (2), and the dielectric layer (A) are restricted by the glass plate 0, and are equivalent to the expansion and contraction of the glass plate 0.

In addition, the metal thin film ■ also serves as a protective film with strong magnetic properties.
is completely maintained M@closed, and a practically sufficient life characteristic can be obtained.

On the other hand, in the method for manufacturing the magneto-optical recording element shown in FIG.
By using the organic substrate (10) with guide grooves, which can be mass-produced, as an auxiliary substrate, the guide grooves can be easily transferred to the metal thin film at a low cost. This makes it possible to shorten the process and has great industrial value.

It doesn't matter how many layers the thin film (2) is made up of, but considering that it has the role of protecting the magnetic film ()], it is important that the organic substrate (10) comes into contact with the peeled atmosphere. It is preferable that the part is made of a noble metal element or a corrosion-resistant alloy, and that the thickness is 0.5 μm or more. Also, for the magnetic film (■) and the dielectric layer (■), a mask or the like is used on a portion of the inner and outer circumferential sides. If consideration is given to prevent the formation of glass plates, the peripheral area of 5 will not be exposed and come into direct contact with the atmosphere, and the life and reliability will be further improved.Furthermore, the laser beam for recording and reproduction will be transmitted from the side of the bonded glass plate 0. In order to make the light incident on the glass plate, the variation in birefringence of the glass plate (0) is important, and it goes without saying that a glass plate must be selected after careful consideration.

〔Effect of the invention〕

As explained above, the magneto-optical recording element and the manufacturing method thereof of the present invention are such that the guide grooves essential to the magneto-optical recording element are formed using an organic disk plate as an auxiliary substrate and a metal thin film with excellent corrosion resistance on the auxiliary substrate. At the same time, this metal thin film is used as a protective layer in the final form of the magneto-optical recording element, which not only provides sufficient life characteristics but also simplifies the manufacturing process such as forming guide grooves. is simplified.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the magneto-optical recording element of the present invention;
FIG. 2 is a diagram showing an example of the method for manufacturing a magneto-optical recording element of the present invention, and the third diagram is a diagram showing an example of a method of bonding a magnetic film and a glass plate. ■...Magnetic film ■...Metal thin film■...Organic adhesive■...Glass plate (10)...Organic substrate agent Patent attorney Norio Chika Ken Yudo Norio Ogo Figure 1 ( a)
(-1,,) (C) (d) (e) Figure 2 Figure 3

Claims (4)

[Claims] (1) A magnetic film with a guide groove having an axis of easy magnetization perpendicular to the film surface, a thin metal film formed on the first main surface side of the magnetic film, and a second main surface side of the magnetic film. 1. A magneto-optical recording element comprising: and a glass plate bonded together with an organic adhesive. (2) The magneto-optical recording element according to claim 1, wherein the metal thin film is made of a noble metal element or a corrosion-resistant alloy in a portion that comes into contact with the atmosphere. (3) The magneto-optical recording element according to claim 1, wherein the thickness of the metal thin film is 0.5 μm or more. (4) forming a metal thin film on an organic substrate having a guide groove; forming a magnetic film having an axis of easy magnetization perpendicular to the film surface on the metal thin film; and forming an organic film on the magnetic film. A method for manufacturing a magneto-optical recording element, comprising the steps of bonding glass plates together with an adhesive and peeling off the organic substrate.