JPS61231168A - Target for sputtering - Google Patents

Abstract

PURPOSE:To produce recording media for magneto-optical storage elements in large quantities at high speed with high reproducibility when the recording media are produced by magnetron sputtering using a ferromagnetic plate target, by embedding a beltlike body of a desired material in the target at a prescribed position. CONSTITUTION:When a plate 5 of a ferromagnetic material such as Fe, Ni or Co is used as a target for sputtering in the production of photomagnetic recording media by magnetron sputtering, chips 6 or a beltlike body 8 of a rare earth element-transition metal alloy contg. at least one among Gd, Td, By and Cr is embedded in the target at a position where the target is acceleratedly consumed. The target is efficiently used without waste nd the sputtering efficiency is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a sputtering target suitable for manufacturing a magneto-optical recording medium using sputtering.

<Prior Art> In recent years, research and development of optical memory devices aiming at high density, large capacity, and high speed access has been actively conducted. Among these, magneto-optical memory, which allows information to be erased and re-recorded, is said to be a promising memory for the future, as it can be applied to document files and the like.

As the memory material for the above-mentioned magneto-optical memory, M n B
Alloys of crystalline materials such as i, rare earths, and transition metals (G
Amorphous materials such as dTbFe, etc.) are well known, but the latter alloy amorphous materials of rare earths and transition metals are currently being used because they require less recording energy and do not produce grain boundary noise. Thin films are the focus of development. In addition, as a manufacturing method for manufacturing an amorphous thin film from the above-mentioned memory material, either vacuum evaporation or sputtering is used, but it is easy to create a uniform film over a large area, and the reproducibility is good. It has been found that the sputtering method is suitable for these reasons.

However, it has been found that it is advantageous to use a special type of sputtering method, magnetron sputtering, because the conventional sputtering method that is commonly used has a slower film deposition rate than the vapor deposition method.

In this magnetron sputtering, a magnetic field is created on the target surface in a direction perpendicular to the electric field, and electrons are confined near the target to efficiently discharge. However, since sputtering is concentrated at the location where the magnetic field is applied, There will be a loss of targets.

FIG. 3 shows an explanatory diagram of the electrode structure for ordinary flat plate magnetron sputtering. 1 is the target, 2 is the magnet,
3 indicates a yoke, and 4 indicates a magnetic flux. When magnetron sputtering is performed with the electrode configuration as shown in FIG. 3, a part of the target is subjected to concentrated sputtering due to the influence of the magnetic field, as shown in FIG. 4, resulting in uneven reduction a. In particular, when ferromagnetic materials such as FeCo and Ni are subjected to magnetron sputtering, the phenomenon of uneven wear becomes strong as described below.

That is, in order to create a magnetic field on the target surface, a magnet 2 is placed inside the electrode as shown in Figure 3, but if the target is a ferromagnetic material, most of the magnetic flux 4 is directed to the target 5 as shown in Figure 5. For this reason, the magnet 2 placed inside the electrode must be made of rare earth cobalt and generate a strong magnetic flux. However, magnetron sputtering When a part of the target 5 becomes unevenly thinned, that part becomes partially thin as shown in FIG. The magnetic field at the part a becomes stronger, and together with the use of a strong magnet as described above, the uneven wear progresses further.On the other hand, as a method of sending magnetic flux out of the ferromagnetic target 5, the above-mentioned method is used. Instead of changing the magnet to a stronger one, it is possible to make the target thinner, but since the magnetic flux exiting to the outside of the target is the leakage part as a result of saturation magnetic flux inside the target, it is not possible to make the target thicker as described above. The argument is exactly the same as in the case of using a strong magnet, and therefore the one-sided loss is also severe.

Therefore, it can be said that the latter case is less preferable than the former because the life of the target is shorter.

As explained above, magnetron sputtering using ferromagnetic materials as a target has the major drawbacks that the target wears down rapidly, has a short target life, and because only a portion of the target is sputtered, most of the target is wasted. be. Next, considering these drawbacks, we replaced the above magnetron sputtering with GdTbF.
Problems when applied to the production of a magneto-optical memory thin film made of a rare earth/transition metal alloy film such as e.g. are explained in detail.

There are two ways to use targets for creating thin films of rare earth/transition metal alloys: one is to prepare the alloy target in advance using an arc melting method, and the other is to arrange rare earth flakes on the transition metal target and perform simultaneous sputtering. The latter is usually used because it is difficult to control the composition.

When the latter method is adopted, the thickness of the rare earth must be sufficiently thin compared to the distance between the electrodes, so a plate with a thickness of about 0.1 to 2 fi is used for a distance of 3 to 6 cea between the electrodes. There must be. However, as mentioned above, due to the phenomenon of uneven wear and the fast sputtering rate, it is necessary to frequently replace (or replenish) the rare earth thin flakes when creating the alloy film, and therefore the latter method is difficult to reproduce. It has been difficult to produce a large quantity of a film with high properties.

<Object of the Invention> The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for efficiently manufacturing a magneto-optical recording medium by sputtering.

<Structure of the Invention> The sputtering target according to the present invention is characterized in that a flake or band-like body made of an alloy to be produced is embedded in a predetermined position of a substrate that has ferromagnetic properties during sputtering. Examples> Examples of the sputtering target according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the structure of an electrode for a magneto-optical memory medium using a sputtering target according to the present invention.

5 is a plate-shaped body made of a ferromagnetic material such as Fe, Co, or Ni, and 6 is a rare earth transition metal alloy such as G d T b Fe. The constituent elements of these alloys are all ferromagnetic, but rare earth transition metal alloys are ferrimagnetic.

That is, the magnetic moment of the rare earth metal element and the magnetic moment of the transition metal are coupled in an antiparallel manner in the alloy. Therefore, the magnetic moment of the entire alloy is smaller than that of a single alloy. Then, as shown in FIG. 1, the magnetic flux in the alloy 6 portion jumps out of the target 5, so that the magnetron sputtering effect becomes greater in the alloy 6 portion.

That is, the rare earth transition metal alloy flakes 6 are made of Fe.

An appropriate position in the ferromagnetic target 5 such as Co, Ni, etc.
By embedding the flakes 6 of the rare earth transition metal alloy in the position where sputtering is most efficient, it is possible to eliminate target waste and increase sputtering efficiency. Here, in order to embed the piece 6 made of a rare earth transition metal alloy in the plate 5 made of a ferromagnetic material, predetermined holes (through holes or slots) are formed in the plate 5 in advance. ,
The piece 6 may be fitted into this hole.

FIG. 2 shows a planar configuration of another embodiment of the sputtering target according to the present invention. As shown in the figure, Fe
, Co, Nt, etc., in a predetermined position (position where sputtering is most efficiently performed)
A target is constructed by burying a strip 8 made of a rare earth transition metal alloy such as dTbFe. According to this structure, the places where the rare earth transition metal alloy is buried can be spread over a wide range within the plate-like body 7, so that the target can be used more efficiently.

By using the target configured as shown in FIGS. 1 and 2 above, a large amount of leakage magnetic flux can be secured, the thickness of the target itself can be increased, and there is no need to use a very strong magnet. As mentioned above, since the thickness of the target itself can be increased, sputtering can be carried out efficiently for a long time, and it becomes possible to produce a large quantity of magneto-optical memory media films with high reproducibility. The material of the memory medium film is GdTbFe or TbFe.

T b D ) F Fe , G d T b D
It consists of an alloy such as y Fe.

In the above embodiments, a sputtering target for producing a rare earth transition metal film for optical memory has been described, but the present invention is not limited to this scope and can be applied in various ways. For example, a CoCr perpendicularly magnetized film is also created by simultaneous sputtering of ferromagnetic Co and paramagnetic Cr, but in accordance with the spirit of the present invention,
By embedding a CoCr alloy in a Co target, efficient magnetron sputtering becomes possible.

In short, when performing magnetron sputtering, the gist of the present invention is to embed the alloy to be produced in the part of the ferromagnetic body that is most likely to be sputtered and use it as a target. Note that it is desirable that the magnetic permeability of the alloy embedded in the ferromagnetic material be low.

<Effects of the Invention> According to the present invention, it becomes possible to mass-produce recording media for magneto-optical storage elements, particularly those made of rare earth and transition metal alloys, at high speed and with good reproducibility.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the configuration of a magnetron sputtering electrode equipped with an embodiment of the sputtering target according to the present invention, and FIG. 2 is an explanatory diagram of the configuration of another embodiment of the sputtering target according to the present invention. , Fig. 3 is a configuration explanatory diagram showing the configuration of a conventional magnetron sputtering electrode, Fig. 4 is a configuration explanatory diagram showing the configuration of a conventional magnetron sputtering electrode with a one-sided target, and Fig. 5 is a ferromagnetic FIG. 6 is an explanatory diagram showing the configuration of a conventional magnetron sputtering electrode including a target made of a solid body. FIG. 1-Target 2-Magnet 4-・Magnetic flux

Claims (3)

[Claims] (1) A sputtering target in which a flake or strip of an alloy to be produced is embedded in a predetermined position of a substrate that exhibits ferromagnetic properties during sputtering. (2) The sputtering target according to claim 1, wherein the sputtering is magnetron sputtering. (3) The material of the ferromagnetic substrate is Fe, Ni,
Fe, Ni, Co, Gd, T
3. The sputtering target according to claim 1, wherein the sputtering target contains at least one of B, Dy, and Cr.