JPH1049923A - Production of magnet-optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magneto-optical recording medium having high quality and high reliability be changing the rations of the respective gases in a gaseous mixture during film formation, thereby changing the atom ratios of Tb and Dy from targets over a layer direction and shortening the production time. SOLUTION: A sialon sintered compact is used as the target 10 of a dielectric layer and a Tb0.20 Dy0.10 Fe0.60 CO0.10 alloy is used as the target for an amorphous magnetic layer by using a sheet type magnetron sputtering device 2. A sialon sintered compact is used as the target 12 for the other dielectric layer and an Al metal is used as the target 13 for a reflection layer. The respective targets are sputtered by setting the gaseous Are at a flow rate of 100 to 50sccm in the total amt. and gaseous Kr at a flow rate of 0 to 50sccm and further the gas pressure at 0.8Pa from four pieces of introducing ports 14. At the time of manufacturing such magneto-optical recording medium, the contents of Tb and Dy are changed by changing the flow rates of the gases Ar and the gaseous Kr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magneto-optical recording medium in which an amorphous magnetic layer made of a TbDyFeCo alloy is formed by sputtering.

[0002]

2. Description of the Related Art An amorphous magnetic layer made of a TbDyFeCo alloy is formed by sputtering using an Ar gas. Or, by changing the area of the target, the composition ratio of the formed amorphous magnetic layer is set to a required value.

[0003] In the amorphous magnetic layer of such a TbDyFeCo alloy, jitter characteristics are improved by changing the atomic ratio between Tb and Dy in the layer thickness direction.
It has been proposed that high performance characteristics without an error rate can be obtained (see Japanese Patent Application No. 8-39723).

[0004]

However, in such sputtering, even if the target alloy composition is set to a required ratio, if the film formation time is prolonged, the composition ratio of the formed layer changes or varies. Therefore, the film formation is temporarily stopped and replaced with a new target. Therefore,
The exchange took time and the cost of the target increased.

[0005] Further, even if an attempt is made to obtain a required film forming composition ratio by changing the sputtering area of the target, there is a problem that the film formation varies, and the film thickness and the composition ratio fluctuate.

In recent years, it has been proposed to form a film of an amorphous magnetic layer using a single-wafer magnetron sputtering apparatus.
A DyFeCo alloy must be used. Therefore, when the atomic ratio is changed over the thickness direction of the amorphous magnetic layer to further improve the magneto-optical characteristics, if the amount of power is changed, the The atomic ratio could not be changed.

Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to reduce the manufacturing time and the manufacturing cost by preventing the replacement of a new target during the film formation. is there.

Another object of the present invention is to provide a high-quality and high-reliability magneto-optical recording medium in which there is no variation among individual products and uniform performance can be obtained over the film surface even in each product. It is in.

Still another object of the present invention is to provide a TbDyFe
It is another object of the present invention to further improve the magneto-optical characteristics such as C / N by changing the atomic ratio as required in the thickness direction of the amorphous magnetic layer made of a Co alloy.

[0010]

SUMMARY OF THE INVENTION The present invention provides a TbDyF
This is a method of forming an amorphous magnetic layer on a substrate by sputtering an alloy target of eCo with a mixed gas of Ar gas and Kr gas, and changing each gas ratio of the mixed gas during the film formation. Thus, the atomic ratio between Tb and Dy is changed in the layer thickness direction.

Another method of manufacturing a magneto-optical recording medium according to the present invention is characterized in that the above-mentioned film formation by sputtering is performed using a single-wafer magnetron sputtering apparatus.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 shows a layer configuration of a magneto-optical recording medium 1 according to the manufacturing method of the present invention, and FIG. 2 shows a schematic configuration of a single-wafer magnetron sputtering apparatus 2 for forming a film on the magneto-optical recording medium 1.

In FIG. 1, reference numeral 3 denotes a substrate made of a resin such as polycarbonate, and a dielectric layer 4 made of, for example, sialon, and an amorphous Tb
A magneto-optical recording layer 5 made of a DyFeCo alloy, a dielectric layer 6 made of sialon or the like, and a reflective layer 7 are sequentially laminated by a sputtering method, and a protective resin layer made of an acrylic resin is further formed on the reflective layer 7 (see FIG. (Not shown).

The dielectric layers 4 and 6 may be formed of silicon oxide, aluminum nitride, titanium oxide, tantalum oxide or the like other than sialon. The reflection layer 7 is made of Al, T
It is formed of at least one metal or alloy of i, Au, Ag, Cu, Pt, Cr, and Ni.

Next, the basic configuration of the single-wafer magnetron sputtering apparatus 2 will be described with reference to FIG. Reference numeral 8 denotes a vacuum chamber. A rotatable substrate support 9 is disposed in the center of the vacuum chamber 8, and the substrate 3 is fixed to one surface of the substrate support 9. A target 10 for the dielectric layer 4, a target 11 for the amorphous magnetic layer 5, a target 12 for the dielectric layer 6, and a target 13 for the reflective layer 7 are provided on the four side walls of the vacuum chamber 8. And, a power application system for applying power between each of the targets 10, 11, 12, 13 and the substrate support 9 is provided. Further, inlets 14 for a mixed gas of Ar gas and Kr gas are formed at the four corners. An exhaust port (not shown) for discharging the residual gas after the film formation is also provided.

In order to form each layer by the single-wafer magnetron sputtering apparatus 2 having the above-described structure, the substrate 3 is fixed to the substrate support 9 and the inside of the vacuum chamber 8 is evacuated. Next, a mixed gas is introduced from the four inlets 14, and power is applied between the substrate support 9 and the target 10 for the dielectric layer 4 to form the dielectric layer 4 on the substrate 3. The substrate support 9 is rotated by 90 degrees to apply electric power between the substrate support 9 and the target 11 for the amorphous magnetic layer 5, thereby forming the amorphous magnetic layer 5 into a film. The body layer 6 and the reflection layer 7 are formed to manufacture the magneto-optical recording medium 1. Thereafter, the inside of the vacuum chamber 8 is returned to the atmospheric pressure, and the magneto-optical recording medium 1 is taken out.

In forming the amorphous magnetic layer 5 of the magneto-optical recording medium 1, a mixed gas of Ar gas and Kr gas is used as a sputtering gas.
The atomic ratio can be set as required by using the difference in the Tb / Dy sputtering rate between the gas and the Kr gas and changing the gas ratio.

Thus, according to the production method of the present invention, Ar / K
The composition ratio of the layer can be adjusted only by changing the r gas ratio, so that even if the film formation time becomes longer and the ratio fluctuates, it can be easily controlled. Therefore, the target can be sufficiently used to a considerable extent without stopping the film formation.

When the single-wafer type magnetron sputtering apparatus 2 is used, each layer can be formed continuously in the small vacuum chamber 8, but on the other hand, depending on the shape and size of the vacuum chamber 8, the target can be formed. The size will be limited. However, in the present invention, the Tb / Dy atomic ratio can be adjusted in the layer thickness direction as required by adjusting the ratio of the sputtering gas without being limited by such size limitation.

In addition, according to the manufacturing method of the present invention, when forming the amorphous magnetic layer 5, the mixed gas ratio of the Ar gas and the Kr gas is changed to change the atomic ratio of Tb and Dy in the layer thickness direction. By changing the ratio, magneto-optical characteristics such as C / N can be improved.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Using a single-wafer magnetron sputtering apparatus 2 as described above, a sialon sintered body as a target 10 for a dielectric layer 4 and a target 11 for an amorphous magnetic layer 5 were used.
An alloy of Tb _0.20 Dy _0.10 Fe _0.60 Co _0.10 was used, a sialon sintered body was used as the target 12 for the dielectric layer 6, and an Al metal was used as the target 13 for the reflective layer 7.
Then, Ar gas is supplied from the four inlets 14 in a total amount of 100.
At a flow rate of ５０50 sccm, Kr gas is supplied at 0 to 50 sccm.
The gas pressure is set to 0.8 Pa and the respective targets are sputtered, whereby the dielectric layer 4 having a thickness of 800 ° is sequentially formed on the polycarbonate substrate 3.
Thus, a magneto-optical recording medium 1 was obtained in which an amorphous magnetic layer 5 having a thickness of 200 Å, a dielectric layer 6 having a thickness of 200 膜厚, and a reflective layer 7 having a thickness of 600 積 層 were laminated.

Next, in producing the magneto-optical recording medium 1, the contents of Tb and Dy and the contents of Ar and Kr were measured by changing the flow rates of Ar gas and Kr gas. The result as shown in FIG. 1 was obtained. In addition, about these measurements, the content was measured by ICP emission analysis.

[0023]

[Table 1]

As is clear from the table, as the Ar content gradually decreases and the Kr content gradually increases, the Tb content decreases and the Dy content increases.

Then, when the Curie temperature with respect to the Dy content was measured, the result as shown in FIG. 3 was obtained.
It can be seen that the required Curie temperature Tc was obtained by changing the flow rates of the Ar gas and the Kr gas.

Next, when the C / N was measured with respect to the change in the flow rate of the Ar gas and the Kr gas, the result shown in FIG. 4 was obtained. That is, with respect to the flow rate (horizontal axis) of the Ar gas, “50”, “70”, and “80” in the figure are gradually reduced during film formation, while the initial flow rate is 100 sccm. The case where the end point is set with each value is shown. Further, regarding the flow rate of the Kr gas, “50”, “30”, and “20” in the figure indicate that the initial flow rate is zero, respectively. On the other hand, a case is shown in which the value is gradually increased during the film formation and the end point is set at each value, but the C / N of the various magneto-optical recording media thus obtained is measured. And plotted, and represents the line connecting each plot.

As is apparent from the results, the required C / N can be obtained by changing the flow ratio of Ar gas / Kr gas in the layer thickness direction.

[0028]

As described above, according to the production method of the present invention, A
Since the composition ratio of the layer can be adjusted only by changing the r / Kr gas ratio, it is not necessary to replace the target as in the related art, thereby shortening the manufacturing time, reducing the manufacturing cost, and as a result, reducing the manufacturing cost. An inexpensive magneto-optical recording medium can be provided.

In the manufacturing method of the present invention, even if a single-wafer magnetron sputtering apparatus is used, a layer whose Tb / Dy atomic ratio is adjusted as required is formed only by adjusting the sputtering gas ratio. be able to.

Furthermore, according to the manufacturing method of the present invention, a layer whose composition ratio is adjusted as required can be easily formed.
There is no variation between individual products, and even within the products, uniform performance can be obtained over the film surface. As a result, a high-performance and highly reliable magneto-optical recording medium can be provided.

Further, according to the present invention, TbDyFeC
By changing the atomic ratio as needed over the thickness direction of the amorphous magnetic layer made of an o-alloy, a magneto-optical recording medium with further improved magneto-optical characteristics such as C / N can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a layer configuration of a magneto-optical recording element of the present invention.

FIG. 2 is a schematic configuration diagram of a single-wafer type magnetron sputtering apparatus.

FIG. 3 is a diagram showing a relationship between Dy content and Curie temperature.

FIG. 4 is a diagram showing a relationship between an Ar / Kr gas amount ratio and C / N.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magneto-optical recording medium 2 Sheet-fed magnetron sputtering apparatus 3 Substrate 4, 6 Dielectric layer 5 Amorphous magnetic layer 7 Reflective layer 8 Vacuum chamber 9 Substrate support 10, 11, 12, 13 Target 14 Inlet

Claims (2)

[Claims] An alloy target of TbDyFeCo is A
A method of forming an amorphous magnetic layer on a substrate by sputtering with a mixed gas of r gas and Kr gas,
A method for manufacturing a magneto-optical recording medium, wherein the atomic ratio of Tb and Dy is changed in the layer thickness direction by changing each gas ratio of the mixed gas during the film formation. 2. A method for manufacturing a magneto-optical recording medium according to claim 1, wherein said amorphous magnetic layer is formed by using a single-wafer magnetron sputtering apparatus.