JP2000129433A - Sputtering target for forming magneto-optical recording medium film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a target for forming a magneto-optical recording medium film in which the concn. of rare earth elements is uniform by sputtering. SOLUTION: In a sputtering target for forming a magneto-optical recording medium film having a compsn. contg., by atom, 10 to 50% rare earth elements, contg., at need, one or two or more kinds among Cr, Nb, Ti, Pt, Si, Al and Ta by 0.1 to 20 atomic %, and the balance transition metals, one side of the target 1 is provided with a slope 5 whose thickness is reduced from the outer circumferential part R to the center part C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering target for forming a magneto-optical recording medium film in which a rare earth element has a uniform composition over the entire film.

[0002]

2. Description of the Related Art Conventionally, as a sputtering target for forming a magneto-optical recording medium film, (a) rare earth elements such as Tb, Gd, Dy and Nd: 10 to 50 atomic%;
The remainder: a sputtering target for forming a magneto-optical recording medium film having a composition composed of a transition metal, or (ii) a rare earth element: 10 to 50 atomic%, Cr, Nb, Ti, Pt, S
One or more of i, Al and Ta: 0.1
2. Description of the Related Art Sputtering targets for forming a magneto-optical recording medium film having a composition of up to 20 at% and a balance of transition metal are known, and these targets are both flat on both front and back surfaces.

As shown in FIG. 4, one side of the target 1 is bonded to a copper backing plate 2 and the bonded target 1 is placed in a sputtering apparatus (not shown) to generate plasma, as shown in FIG. A disk is manufactured by performing sputtering while forming a magneto-optical recording medium film 4 on the surface of a substrate made of glass or resin.

[0004]

When a magneto-optical recording medium film is formed by sputtering using the conventional target containing a rare earth element, the center portion c and the peripheral portion r of the obtained magneto-optical recording medium film 4 are formed. In this case, the content of the rare earth element is different, the content of the rare earth element in the peripheral portion r of the magneto-optical recording medium film is larger than the content of the rare earth element in the central portion c, and the content of the rare earth element is uniform throughout. Was not obtained. The cause is that when sputtering is performed using a conventional flat disk-shaped target containing a rare earth element, the rare earth element has a property of scattering from the inside toward the outer periphery as shown by S in FIG. It is considered that the content of the rare earth element in the peripheral portion r of the magneto-optical recording medium film obtained by sputtering is larger than the content of the rare earth element in the central portion c. The content of the rare earth element in the magneto-optical recording medium film formed on the substrate is at the center c.
And there is a variation of ± 0.5 atomic% or more in the peripheral portion r,
This is not preferable because it has a significant effect on the characteristics of the disc. An object of the present invention is to provide a target capable of forming a magneto-optical recording medium film having a rare earth element content uniformly over the entire substrate.

[0005]

Means for Solving the Problems The present inventors obtain a sputtering target in which the content of the rare earth element in the peripheral portion r and the central portion c of the magneto-optical recording medium film obtained by sputtering is uniform. While conducting research, sputtering using a target provided with an inclined surface 5 whose thickness decreases from the outer peripheral portion R toward the central portion C as shown in the cross-sectional views of FIGS.
In the magneto-optical recording medium film 4 of FIG. 4 obtained as described above, the variation between the content of the rare earth element in the peripheral portion r and the content of the rare earth element in the central portion c is within the range of ± 0.5 atomic%. It has been found that a magneto-optical recording medium film having a uniform content of rare earth elements can be obtained as a whole.

The present invention has been made based on this finding. As shown in the sectional views of FIGS. 1 to 3, (1) one side of the target 1
A sputtering target for forming a magneto-optical recording medium film provided with an inclined surface 5 whose thickness decreases toward the surface, (2) magneto-optical recording having a composition comprising a rare earth element: 10 to 50 atomic% and a balance: transition metal In the sputtering target for forming a medium film, an outer peripheral portion R is formed on one surface of the target 1.
A sputtering target for forming a magneto-optical recording medium film provided with an inclined surface 5 whose thickness decreases from the center toward the central portion C;
(3) Rare earth element: 10 to 50 atomic%, Cr, Nb, T
One or more of i, Pt, Si, Al, and Ta: a sputtering target for forming a magneto-optical recording medium film having a composition of 0.1 to 20 atomic% and a balance of transition metal; The present invention is characterized in that a sputtering target for forming a magneto-optical recording medium film is provided, on one surface of a target 1, an inclined surface 5 whose thickness decreases from an outer peripheral portion R toward a central portion C.

The composition of the sputtering target for forming a magneto-optical recording medium film according to the present invention is as follows:
A composition containing 50 atomic% and a balance of a transition metal such as Fe and Co is preferable, and this target is further added with one or more of Cr, Nb, Ti, Pt, Si, Al and Ta: It is more preferable to add 0.1 to 20 atomic%. Among them, a composition containing Tb: 20 to 24 atomic%, Cr: 2 to 4 atomic%, Co: 6 to 9 atomic%, and the balance: Fe It is most preferred to have

Therefore, the present invention provides (4) Tb: 2
A sputtering target for forming a magneto-optical recording medium film having a composition of 0 to 24 atomic%, Cr: 2 to 4 atomic%, and Co: 6 to 9 atomic%, with the balance being Fe
It is characterized by a sputtering target for forming a magneto-optical recording medium film provided with an inclined surface 5 whose thickness decreases from the outer peripheral portion R of the target 1 toward the central portion C.

[0009] From the outer peripheral portion R of the target 1 to the central portion C
2 may be any surface such as a spherical surface, a paraboloid, an ellipsoid, a hyperboloid, or a conical surface, but may be a conical surface as shown in the sectional view of FIG. A spherical surface or a paraboloid as shown in the sectional view of FIG. The inclined surface 5 provided in the sputtering target for forming a magneto-optical recording medium film according to the present invention does not need to be a complete inclined surface from the outer peripheral portion R of the target toward the center, and is flat as shown in the sectional view of FIG. The inclined surface 5 whose thickness decreases toward the central portion C may be used.

[0010] The central portion thickness of C of the target formed by the inclined surfaces (H _C) and the outer peripheral portion thickness of the R (H _R)
Is preferably in a range of H _C / H _R = 0.8 to 0.95. In the magneto-optical recording medium film obtained by sputtering using a target having H _C / H _R > 0.95, the content of the rare earth element in the outer peripheral portion r of the film is 0% of the content of the rare earth element in the central portion c. .5 atomic%.
It is not preferable because it cannot be used as a disc. Also H
The content of the rare earth element in the central portion c of the magneto-optical recording medium film obtained by sputtering using a target having _C / H _R <0.8 is such that the content of the rare earth element in the outer peripheral portion r is 0.5 atomic%. Is not preferable because it cannot be used as a disc.

Therefore, the present invention provides (5) a slope provided from the outer peripheral portion C provided on one surface of the target described in the above (1), (2), (3) or (4) toward the central portion C. Depending on the surface, the thickness at the center of the target (H _C )
And the thickness of the outer peripheral portion (H _R ) is H _C / H _R = 0.
And a sputtering target for forming a magneto-optical recording medium film having a thickness of 8 to 0.95.

The sputtering target for forming a magneto-optical recording medium film according to the present invention is obtained by melting a raw material so as to have a desired component composition and subjecting the alloyed melt to gas atomization or casting in an inert gas atmosphere. The obtained ingot is pulverized to produce an alloy powder having a larger average particle diameter: 50 to 60 μm, and the alloy powder is heated at a temperature of 900 to 1100 ° C. and a pressure of 100 to 2 μm.
It is manufactured by hot pressing under conditions of 00 kgf / cm ² and holding for 0.5 to 3 hours.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Tb:
Contains 24 atomic%, Co: 8 atomic%, Cr: 3 atomic%, has a composition of balance Fe, and has an average particle diameter of 100 μm.
m, and the alloy powder was filled in a graphite mold. The temperature was 1000 ° C., the pressure was 150 kgf / cm ² ,
The diameter is obtained by hot pressing under the condition of holding for 2 hours:
A hot-pressed body having dimensions of 127 mm and an outer peripheral thickness (H _R ) of 10 mm was prepared, and this was used as a conventional sputtering target for forming a magneto-optical recording medium film (hereinafter referred to as a conventional target). Then, one side of the hot pressed body is processed into a spherical surface having the values of the thickness (H _C ) and H _C / H _R at the center as shown in Table 1, whereby the sputtering target for forming a magneto-optical recording medium film of the present invention is obtained. (Hereinafter, the target of the present invention) 1 to 3 and sputtering targets for forming a film of a comparative magneto-optical recording medium (hereinafter, a comparative target) 1 to 2 were produced.

These targets 1 to 3 of the present invention, comparative targets 1 and 2 and a conventional target were mounted in a sputtering chamber, and a circular magneto-optical disk having a thickness of 1 μm was formed on a glass plate under the conditions of Ar pressure: 1 Pa, DC power: 500 W. A recording medium film is formed, and the Tb concentration (Tb ₀ ) at the center of the circular magneto-optical recording medium film and the Tb at a position 30 mm away from the center are determined.
The concentration of b (Tb ₃₀ ) was measured, and the value of Tb ₀ -Tb ₃₀ was determined. These values are shown in Table 1.

[0015]

[Table 1]

[0016]

According to the results shown in Table 1, the targets 1 to 3 of the present invention have a Tb concentration (Tb ₀ ) at the center of the circular magneto-optical recording medium film and 30 m from the center as compared with the conventional targets.
It can be seen that the variation in the concentration of Tb (Tb ₃₀ ) at a position m away is small and within the range of ± 0.5 atomic%. However, comparison target 1-2 of H _C / H _R is out of the range of 0.8 to 0.95, the large variation in the Tb concentration value of Tb ₀ -Tb ₃₀ increases, ± 0.5 atomic% It can be seen that the range greatly falls outside the range. As described above, the present invention can provide a sputtering target for forming a magneto-optical recording medium film capable of forming a magneto-optical recording medium film having a uniform concentration of a rare earth element by sputtering. It can greatly contribute to development.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a sputtering target for forming a magneto-optical recording medium film according to the present invention.

FIG. 2 is an explanatory sectional view of a sputtering target for forming a magneto-optical recording medium film according to the present invention.

FIG. 3 is an explanatory sectional view of a sputtering target for forming a magneto-optical recording medium film according to the present invention.

FIG. 4 is an explanatory cross-sectional view for explaining a problem of sputtering using a conventional sputtering target for forming a magneto-optical recording medium film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Target 2 Backing plate 3 Substrate 4 Magneto-optical recording medium film 5 Inclined surface

Claims (5)

[Claims] 1. A sputtering target for forming a magneto-optical recording medium film, wherein an inclined surface having a thickness decreasing from an outer peripheral portion toward a central portion is provided on one surface of the target. 2. A sputtering target for forming a magneto-optical recording medium film having a composition comprising a rare earth element: 10 to 50 atomic% and a balance: transition metal, wherein a thickness of one side of the target from an outer peripheral portion to a central portion is increased. 1. A sputtering target for forming a film on a magneto-optical recording medium, wherein the sputtering target has an inclined surface with a reduced value. 3. Rare earth element: 10 to 50 atomic%, Cr,
One or more of Nb, Ti, Pt, Si, Al and Ta: A sputtering target for forming a magneto-optical recording medium film having a composition comprising 0.1 to 20 atomic% and the balance being a transition metal. 3. The sputtering target for forming a magneto-optical recording medium film according to claim 1, wherein an inclined surface whose thickness decreases from an outer peripheral portion toward a central portion is provided on one surface of the target. 4. Tb: 20 to 24 atomic%, Cr: 2 to 4
In a sputtering target for forming a magneto-optical recording medium film having a composition consisting of atomic% and Co: 6 to 9 atomic%, and the balance being Fe, the slope on one surface of the target decreases in thickness from the outer periphery toward the center. A sputtering target for forming a magneto-optical recording medium film, wherein the sputtering target has a surface. 5. The relationship between the thickness (H _C ) at the center of the target and the thickness (H _R ) at the outer periphery of the target is determined by an inclined surface provided on one surface of the target, where H _C / H _R = 0.8. 5. The sputtering target for forming a magneto-optical recording medium film according to claim 1, wherein the thickness is set to 0.95.