JPH01105518A - Sputtering target - Google Patents

Abstract

PURPOSE:To form a magnetic film which ensures reliability for a long period, by making a sputtering target contain 200PPM or less carbon by weight rate and displaying magnetic performance which is held by a magnetic thin film originally. CONSTITUTION:A sputtering target forms magnetic thin films comprising heavy rare earth and transition metals as principal compositions by a sputtering process. In such a case, its target contains 200PPM or less carbon by weight rate. Its compositions are represented by an expression in terms of atomic rate: {(LR)X(HR)1-X}YA100-Y where LR contains a kind or more of light rare earth metals selected out of those; Ce, Pr, Nd, and Sm and HR contains a kind or more of the heavy rare earth metals out of those; Gd, Tb, and Dy and A contains an either one out of Fe and Co and further, X and Y are as follows: 0.05<=X<=0.60, 15<=Y<=40. In this way, magnetic performance held by the magnetic thin films originally is displayed to form the magnetic films which ensure reliability for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sputtering e-target used for producing a heavy rare earth gold scrap/transition metal alloy magnetic thin film used, for example, in magneto-optical elements.

[Conventional technology]

Vacuum evaporation, sputtering, etc. are generally used to form heavy rare earth metal/transition gold layer alloy thin films.

Among these, sputtering is the most widely used method today because it produces films with better magnetic properties than other film formation methods, and mass production has significantly improved due to advances in magnetron sputtering. .

As a method of forming multi-element alloy thin films by sputtering, a film with a uniform composition can be obtained in the thin film direction and in-plane direction, and even if sputtering is repeated many times, the composition of the obtained film remains constant. , a method of sputtering an alloy target is suitable.

[Problem that the invention seeks to solve]

However, if the alloy target contains many impurities,
Spackling causes impurities to be mixed into the magnetic thin film. This deteriorates the magnetic properties of the magnetic thin film and at the same time reduces long-term reliability. Therefore, the present invention is intended to solve these problems, and its purpose is to make it possible to create a magnetic film that fully brings out the inherent magnetic performance of the magnetic thin film and also ensures long-term reliability. to,
The purpose is to provide sputtering targets.

[Means for solving problems]

The sputtering target of the present invention is a sputtering target used for creating a magnetic thin film containing heavy rare earth metals and transition metals as main components, and is characterized by having a carbon content of 200 PPM or less by weight. Furthermore, the sputtering target
When the composition is expressed in atomic ratio as ((LR)X'(HR)I-x)yA+*o'-y, (LR is the light rare earth metal Ce.

Prs Ndt Sm, 1u class or more, HR is heavy rare earth fJ gold rlAGd, Tb, Dy > 1 type or more, A
must contain either Fe or Co (LR),
a) Xs'j representing an element other than (HR) is in the range of 0.05≦X≦0.60 and 15≦y≦40.

(Examples) Hereinafter, the present invention will be described in detail based on Examples. Unless otherwise specified, all sputtering targets used in this example were made by heating and melting high-purity metal raw materials with a purity of 99.0% or higher in vacuum in an induction heating furnace, and then casting in an argon atmosphere. Diameter 10 cm s Thickness 5
It was processed into a disk shape of mm, and was further bonded to a puffing plate made of a copper plate using an indium hanger. By changing the raw material purity and casting conditions, the carbon concentration can be reduced to ff.
A target having an i amount ratio of 1100PP to 800PPM was obtained. The carbon concentration in the sintered target used as a comparative example was about 5000 PPM by weight.

Further, the compositions shown below are in atomic ratio.

(Example 1) Table 1 shows the composition of the created casting target. Using these sputtering targets, the initial vacuum level is 5.
．． After evacuating the chamber to below 0XIO-'Toor, Ar was used as a carrier gas, and 300W of high-frequency power was applied to the cathode to deposit 50% on a glass substrate.
A film was formed to a thickness of nm. In order to prevent oxidation of the magnetic film, a mixture of aluminum nitride and silicon nitride was continuously formed to a thickness of 1100 nm without breaking the vacuum. Figure 1 shows the composition of sample number 1 with a carbon concentration of 1100PP and 20PP by weight.
Three types of sputtering: 0PPM and 800PPM
A Faraday loop immediately after film formation of a sample created using a target, and a
Table 2 shows the Faraday rotation angle and the change in the coercive force obtained from the Faraday loop, in order of the carbon concentration of the sputtering target. Both the angle and the coercive force in Table 2 are thick (and 60℃, R890%, 20
Even if it is left for a long time, the coercive force does not decrease by 7 rad per rotation angle. Similar results were obtained for samples prepared using sputtering targets having compositions of sample numbers 2 to 8. From this, it can be seen that creating a magnetic thin film using a Subatari/Goo target with a low carbon concentration is effective in improving the magnetic properties and long-term reliability of the magnetic properties.

(Example 2) A mixture of aluminum nitride and silicon nitride was layered on a polycarbonate substrate with guide grooves to form a layer of 110% of aluminum nitride and silicon nitride.
The film was formed to a thickness of 0 nm, and the carbon concentration was 1100 PP by weight with the composition of sample number 1.

Targets of 200 PPM and 800 PPM; as a comparative example, a sintered target with the composition of sample number 9 (carbon concentration 5
A magneto-optical recording layer is formed with a thickness of 40 nm by sputtering four types (000 PPM), and a second protective layer having the same composition as the first protective layer is formed on the magneto-optical recording layer with a thickness of 1100 nm. Four types of magneto-optical recording media were manufactured using this method. 4 types of recording media at 60℃, RH90%,
A weather resistance test was conducted by leaving it in a constant temperature and humidity chamber. Figure 2 shows the C
It shows the change in N ratio over time. The evaluation was performed under the conditions of a linear velocity of 4°7 m/s1, a recording frequency of I MHz, and a resolution band of 30 KHz.

As is clear from Figure 2, when comparing recording media with the same composition, the recording medium produced by sputtering a target with a lower carbon content has a higher CN content.
CN ratio, and the decrease in CN ratio is small over a long period of time.

A recording medium created by sputtering a sintered target with a high carbon content has a CN ratio immediately after creation of a recording medium created by sputtering a target having the composition of sample number 1 with a carbon concentration of 1100 PP by weight. Although it is almost the same as the CN ratio, the deterioration rate of the CN ratio is 4! This is the largest value among the Ol class recording media. Results similar to those of sample number 1 were obtained for samples prepared using targets having the compositions of sample numbers 2 to 8.

From the above, the carbon content in the target is 9rf! It can be seen that keeping k as low as possible is effective in improving long-term reliability.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to bring out the characteristics of a magnetic thin film whose main components are heavy rare earth metals and transition metals, and it has the effect of improving long-term reliability.

[Brief explanation of the drawing]

Figure 1 (a), (b), and (c) are sample number 1, respectively.
With the composition, the carbon concentration is tooppM and 200PP by weight.
FIG. 3 is a diagram showing the magnetic field dependence of the Faraday rotation angle of a magnetic film immediately after being formed by sputtering M and 800 PPM targets. Figure 1, °(d), (e), and (f) are the composition of sample number 1, and the carbon concentration is 1100P in weight ratio.
Magnetic films formed by sputtering P, 200PPM and 800PPM targets were heated at 60°C and RH90%.
FIG. 3 is a diagram showing the magnetic field dependence of the Faraday rotation angle of a magnetic film after being left in a constant temperature and humidity chamber for 20 hours. Figure 2 shows that the composition of sample number 1 has a carbon concentration of 11% by weight.
The carbon concentration of the targets of 00PP, 200PPM and 800PPM, and the composition of sample number 9 is 5000 by weight.
FIG. 3 is a diagram showing the change over time in the CN ratio when a magneto-optical recording medium prepared by sputtering a PPM target is left in a constant temperature and humidity chamber of 60'C1RH90%. In addition, the composition of sample number 1 has a carbon concentration of 1100PP by weight,
O has the composition of sample number 1, and the carbon concentration is 200P by weight.
PM1mu has the composition of sample number 1 and the carbon concentration is 80% by weight.
0 PPM, X represents a magneto-optical recording medium manufactured by sputtering a target having the composition of Sample No. 9 and a carbon concentration of 5000 PPM in ffi amount ratio.・Applicant Seiko Epson Co., Ltd. Figure 1 (2) Figure 1 (e-) Figure 1 (C) al-en]) Figure 1 (f-n)

Claims (1)

[Claims] (1) (In a sputtering target used when creating a magnetic thin film containing heavy rare earth metals and transition metals as main components by sputtering method, the carbon content is 200 PPM or less by weight ratio. Characteristic sputtering target. (2) The composition of the sputtering target is {(LR)_X(HR)_1_-_X}_YA_1_0 in atomic ratio.
When expressed as ＿0＿－＿Y (however, LR is light rare earth metal C
e, Pr, Nd, and Sm, HR is one or more of the heavy rare earth metals Gd, Tb, and Dy, A is Fe,
Must include one of Co (LR), (HR)
The sputtering target according to claim 1, wherein X and Y are in the following ranges: 0.05≦X≦0.60 and 15≦Y≦40.