JPH0517868A - Production of sputtering target - Google Patents

Abstract

PURPOSE:To produce a sputtering target increased in saturation magnetic flux, excellent in soft-magnetic properties, having superior heat resistance, and facilitating the formation of carbide dispersion type soft-magnetic film. CONSTITUTION:A powder of >=50mum average grain size of at least one element among Fe, Co, and Ni or alloy thereof previously subjected to reduction treatment in a reducing atmosphere of hydrogen gas, etc., a powder of at least one element among Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W, and a C powder are mixed by means of a powder mixer, etc. The resulting powder mixture is compacted and is then sintered in a reducing atmosphere of hydrogen gas, etc., again or sintered by means of hot isostatic pressing. At this time, when sintering temp. exceeds 1000 deg.C, the reactions between the group IVa, Va, and VIa elements and C can be accelerated and the carbides of the group IVa, Va, and VIa elements can be formed in the resulting sintered compact, and, as a result, the initial purpose can be accomplished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputter target used for forming a soft magnetic thin film for forming a magnetic pole material of a magnetic head for high density magnetic recording which requires a high saturation magnetic flux density.

[0002]

2. Description of the Related Art Generally, the coercive force Hc of a recording medium must be increased in order to increase the density of magnetic recording.
At the same time, a magnetic head material having a high saturation magnetic flux density is required. Conventionally, ferrite, permalloy, sendust, Co-based amorphous alloys, etc. have been used as materials for forming magnetic poles of magnetic heads for magnetic recording and reproduction.

[0003]

[Problems to be Solved by the Invention] However, ferrite,
Permalloy and Sendust have a small saturation magnetic flux density with respect to the coercive force of the recording medium, and have a drawback that sufficient high density magnetic recording cannot be realized. Further, the saturation magnetic flux density of Co-type amorphous is 13 to 15 kG, which is Hc of the current magnetic recording medium.
However, it has a drawback that it lacks thermal stability and crystallizes when exposed to a high temperature of several hundreds of degrees Celsius or more in the glass welding process, so that its good soft magnetic properties are lost.

Even when a single layer film is obtained from an alloy system having a high saturation magnetic flux density as a magnetic pole material of a magnetic head, it is softened in a high frequency region due to epitaxial growth during film formation and crystal grain growth at a high temperature during head processing. There is a problem that the magnetic characteristics are deteriorated. There is a method of laminating as one means for solving this, but when the intermediate layer itself has poor thermal stability, it is exposed to a high temperature to cause diffusion of constituent elements at the interface, resulting in lamination soft magnetic properties. Original high magnetic flux density,
The high permeability feature is lost.

F as a magnetic pole material that overcomes these drawbacks
A soft magnetic thin film material in which fine particles of IVa, Va, VIa group carbides or the like are dispersed in a matrix of e, Co, Ni, or an alloy thereof to give high permeability, high saturation magnetization, and good heat resistance. Is in the spotlight. In order to add carbon to the film in such a film, a composite target method is used in addition to the reactive sputtering method using a reaction gas such as CH ₄ . However, all of them are suitable for film formation at the research and development stage, but are unsuitable for mass production. This fine particle-dispersed soft magnetic film has IVa, Va,
This is made use of the fact that the group VIa element has a large ability to form nitrides and carbides, but this characteristic is rather a major obstacle when manufacturing a sputter target. That is, IVa,
Even if a film is formed using a target containing nitrides and carbides of Va and VIa group elements, IVa and V are formed in the film immediately after the film formation.
Since nitrides and carbides of the a and VIa group elements are present, it is extremely difficult to obtain a good soft magnetic film.

Therefore, the technical problem of the present invention is to solve the above-mentioned problems, and to form a carbide-dispersed soft magnetic film having a large saturation magnetic flux density, excellent soft magnetic properties, and good heat resistance. It is to provide a method for forming a sputter target that facilitates the above.

[0007]

According to the present invention, Fe,
At least one of Co and Ni, or an alloy fine powder thereof, and Ti, V, Cr, Zr, Nb, Mo, Hf,
A step of mixing at least one powder of Ta and W, and a powder of C, a step of molding the mixed powder, and a step of sintering the molded powder at a temperature of 1000 ° C. or lower. And including IVa in the magnetic metal matrix,
A method of manufacturing a sputter target for forming a ferromagnetic alloy thin film, characterized in that particles of Va, VIa group elements and C are independently present.

[0008]

[Function] At least one of Fe, Co, and Ni, which has been reduced in advance in a reducing atmosphere such as hydrogen gas, or a powder of an alloy thereof having an average particle size of 50 μm or less, and T
At least one kind of powder among i, V, Cr, Zr, Nb, Mo, Hf, Ta and W and the powder of C are mixed with a mixer or the like. After molding this mixed powder, it is sintered again in a reducing atmosphere such as hydrogen gas, or in hot isostatic pressure. At this time, if the sintering temperature exceeds 1000 ° C, IV
Reaction of a, Va, VIa group elements and C is promoted and
Carbides of IVa, Va, and VIa group elements are formed, and the initial purpose cannot be achieved. The average particle size is 50μ
When sintered with Fe, Co, Ni, or their alloy powders exceeding m 3, even if sintered under hot isostatic pressure, 1
At a temperature of 000 ° C or lower, the sintered density does not increase sufficiently.

In the sputter target of the present invention,
IVa, V in magnetic metal matrix of Fe, Co, Ni
Fine particles of a and VIa group elements and fine particles of C are dispersed independently of each other. Therefore, the target surface is in the same state as the composite target, and the alloy film can be easily obtained. Further, since the non-magnetic element is dispersed in the target, the magnetic permeability is lowered, so that it is easy to obtain a leakage magnetic flux, and it is extremely easy to perform magnetron sputtering.

[0010]

EXAMPLES Examples of the present invention will be described below based on experimental results.

In one embodiment of the present invention, F is used as the magnetic metal.
e, Ta and C are used as additional elements. 69.3 at% Fe-7.7 of Fe powder having an average particle size of 3.0 μm reduced in hydrogen gas, Ta powder of 100 mesh or less and 325 mesh or more, and C powder, which are similarly reduced.
After mixing and molding at a ratio of at% Ta-23.0 at% C, it is sintered at 800 ° C. in hydrogen gas. The X-ray diffraction pattern of the sintered body of this example obtained at this time is shown in FIG. For comparison, the X-ray diffraction pattern of the alloy of Comparative Example obtained by melting with the same composition is shown in FIG. 1 (b). Only the Fe and Ta peaks of the simple substance are observed from the sintered body of the present example, while the alloy obtained by melting contains α-Fe and compounds such as TaC and Fe ₃ C. Exists.

Next, a film forming experiment was carried out by a magnetron sputtering method using these two types of targets. Hereinafter, they are referred to as a sintering target and a melting target, respectively. Prior to sputtering, first evacuate the vacuum chamber to 1 × 10 ⁻⁸ Torr or less, and then introduce Ar gas,
A gas pressure was set to 3 mTorr and a film having a film thickness of about 5.0 μm was obtained.
Crystallized glass was used for the substrate. The X-ray diffraction pattern of the thin film obtained from the sintered target is shown in FIG.
The X-ray diffraction pattern of the film obtained from the dissolution target of the comparative example is shown in (b). The film obtained from the sintered target of one example of the present invention is amorphous, whereas the film obtained from the melted target shows the presence of Fe ₃ C and TaC.

Next, these films were heat-treated at 600 ° C. for 20 minutes. Figure 3 shows the hysteresis curve after heat treatment
Shown in (a) and (b). (A) is a film obtained from a sintered target of one example of the present invention, and (b) is a hysteresis curve of film formation obtained from a dissolution target of a comparative example. In one embodiment of the present invention, Hc shows a good soft magnetic property of substantially 49 A / m, while in the comparative example, a snake-type hysteresis curve is exhibited and the coercive force is about 4000 A / m, which is higher than that of the former. Very big.

[0014]

As described above, according to the method for producing a sputter target of the present invention, since it has a sintering step at 1000 ° C. or less, it has a large saturation magnetic density, excellent soft magnetic characteristics and heat resistance. This has the effect of facilitating the formation of a good carbide-dispersed soft magnetic film.

[Brief description of drawings]

FIG. 1A is a diagram showing an X-ray diffraction pattern of a target of an example of the present invention, and FIG. 1B is a diagram of a target of a comparative example.

FIG. 2A is a diagram showing an X-ray diffraction pattern of a Fe—Ta—C thin film by each target of FIG. 1A and FIG. 1B.

FIG. 3 (a) is a diagram showing a hysteresis curve of each film formation of FIG. 2 (a) and FIG. 2 (b).

Claims (1)

What is claimed is: 1. At least one of Fe, Co, and Ni, or an alloy fine powder thereof, and Ti, V, Cr, and Z.
a step of mixing at least one of powders of r, Nb, Mo, Hf, Ta, and W, and a powder of C; a step of molding the mixed powder;
A step of sintering at a temperature of ℃ or less, for forming a ferromagnetic alloy thin film, characterized in that particles of group IVa, Va, VIa and C are independently present in the magnetic metal matrix. Method for manufacturing sputter target.