JPS60230903A - Production of alloy target - Google Patents

Abstract

PURPOSE:To produce a transition metal-rare earth alloy target having high density in the stage of producing the alloy target for forming a thin transition metal-rare earth film by making the powder of a raw material mixture contg. the transition metal in the smaller amt. than the amt. of the target component then mixing the powder with the remaining transition metal powder and molding and sintering the mixture. CONSTITUTION:The transition metal such as Co or Fe is first mixed with the rare earth element such as Gd at a ratio smaller by about 1-10% than the prescribed target value in the stage of producing the target for forming the transition metal-rare earth alloy such as Co-Gd or Fe-Gd as the a thin magnetic film for an optomagnetic recording disk by a PVD method. Such mixture is melted in a non-contaminating atmosphere and is then cooled and crushed in an inert atmosphere consisting of Ar, etc. The remaining 1-10% transition metal such as Co or Fe which is deficient is added to such powder and the mixture composed thereof is sintered at a high temp. in an atmosphere consisting of He, Ar, etc. by which the target consisting of the transition metal-rare earth alloy having high density and high strength is produced.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is applicable to manufacturing an alloy target used when forming a magnetic thin film for a magneto-optical recording disk by a PVD method (physical vapor deposition method), for example. The present invention relates to a method of manufacturing an alloy target for thin film formation suitable for.

(Prior Art) Interest in high-density memory has increased significantly, and various memory media have been developed. Among these, a magneto-optical memory records information on a magnetic material using light (actually, in many cases, heat), and uses a disk surface with a magnetic thin film formed thereon. The magnetic thin film material includes transition metal-rare earth metal,
For example, alloys based on nigga such as Co-Gd and Fe-Gd, or ternary alloys such as Co-Gd-Tb and Fe-Gd-Tb are considered promising.

Conventionally, when manufacturing the above-mentioned magneto-optical recording disk, there has been a method of forming the above-mentioned magnetic thin film material on the surface of a circular base molded from synthetic resin or the like by the PVD method. In this method, for example, a sputtering device is used as the PVD method. In this sputtering apparatus, an alloy target having a composition approximately equal to that of the magnetic thin film is placed in a vacuum container, and a circular base on which the magnetic thin film is to be formed is placed facing the alloy target, and the sputtering device is placed in a vacuum container. 1O-2To of argon gas
rr and a high frequency of 1 to 2 KV at 10-odd MHz is applied to cause a discharge, and the argon ions in the plasma generated by the discharge collide with the alloy target, and the transition is driven out by the collision energy at that time. Metals and rare earth elements are attached to the base.

As described above, an alloy target is required when forming a magnetic thin film by the PVD method, but in the conventional case, manufacturing an alloyed transition metal-rare earth plate alloy target is This is difficult because the target becomes extremely brittle, and the shape of the target makes it impossible to use the above-mentioned transition metal-rare earth plate alloy target. In the conventional case, single transition metals and rare earths in the form of plates are arranged alternately and repeatedly in a predetermined blending ratio as targets, and when the respective transition metals and rare earths have evaporated during sputtering, the target In some cases, transition metals and rare earths were deposited together on a substrate. However, this method has the problem that it is difficult for the transition metal-rare earth magnetic thin film deposited on the substrate to be uniform, and therefore the characteristics tend to be non-uniform.

Therefore, it would be desirable if a transition metal-rare earth alloyed plate-like target could be obtained because the above-mentioned problems would be solved. Therefore, it is conceivable to manufacture a plate-shaped alloy target using a powder metallurgy body by forming and sintering a mixed powder of transition metal powder and rare earth powder in a blending ratio corresponding to the target component, but rare earth elements are extremely active. Therefore, when rare earth powder with a large surface area is handled, contamination becomes extremely large, making it impossible to obtain a good quality alloy target and, at the same time, making it impossible to obtain one with sufficient sintered density. .

(Purpose of the Invention) This invention has been made by focusing on the conventional problems as described above, and it is possible to manufacture plate-shaped alloy targets using powder metallurgy techniques, and it is possible to manufacture high-density alloy targets. The aim is to enable production without contamination.

(Structure of the Invention) When producing a transition metal-rare earth alloy target for forming a thin film, the present invention produces a transition metal-rare earth alloy powder having a smaller amount of transition metal than the target component by a melting and pulverizing method. The feature # is that the alloy powder and the transition metal powder remaining with respect to the target component are mixed and then molded and sintered.

As the transition metal constituting the alloy target of this invention, transition metals such as Co and Fe are used, and as rare earths, rare earths such as Gd and Tb are used. and,
When producing a transition metal-rare earth alloy powder with a smaller amount of transition metal than the target component, for example, the amount of transition metal and rare earth can be reduced by 1-10% less than the target value. and in a non-contaminated atmosphere, such as plasma skull melting (PSC) or vacuum induction melting (VIP).
After that, it is crushed in a non-oxidizing atmosphere such as an inert atmosphere such as Ar. In addition, methods for producing the alloy powder include a method of mechanically crushing the transition metal-rare earth solidified agglomerate, a method of pulverizing the transition metal-rare earth molten metal by an atomization method, a centrifugal spraying method, etc. be done.

Next, the transition metal-rare earth alloy powder and the remaining transition metal powder, for example, about 1-10% of the target component, are mixed and formed into a shape corresponding to the shape of the desired alloy target. . This molding can also be performed at high temperature in an atmosphere of helium, argon, etc. or in vacuum.

Thereafter, the target is sintered in a non-contaminated atmosphere such as vacuum or inert gas in the molding device or in a separate device to obtain a transition metal-rare earth alloy target having the target component. In the alloy target thus obtained, the transition metal powder acts as a binder for the transition metal-rare earth alloy powder, and the target becomes a strong sintered body whose shape can be reliably maintained.

(Example) First, an Fe-Gd alloy ingot was produced by melting in a plasma skull furnace in an argon atmosphere at a ratio of 57% by weight of Fe as a transition metal and 43% by weight of Gd as a rare element. . Next, the alloy ingot was mechanically crushed using a crusher to obtain Fe-Gd alloy powder. Next, the Fe-G
After mixing approximately 7.5% Fe powder with the d alloy powder and making it into a uniform mixed powder using a ball mill, it is placed in a mold that forms a molding space that matches the dimensions of the plate-shaped alloy target to be manufactured. The mixed powder was added and compacted to obtain a plate-shaped compact having a diameter of 250 mm and a thickness of 5 mm. Next, the plate-shaped molded body was sintered in an Ar atmosphere, and then finished by mechanical polishing so that the surface roughness was 10 to 15 ILm. The alloy target thus obtained is approximately 60 wt% Fe-40 wt% Gd, can maintain its shape well, and can be used in PV applications such as sputtering equipment.
It was strong enough to be used as a target for equipment.

Next, the alloy target is placed in a target holder of a sputtering device, a high frequency power source is connected, and a resin circular substrate is placed in the substrate holder, sputtering is performed in an Ar'9 atmosphere, and sputtering is performed on the substrate. Adhered Fe-
When the Gd alloy thin film was examined, it was confirmed that it was an extremely homogeneous magnetic thin film.

(Effects of the Invention) As explained above, in the present invention, when producing a transition metal-rare earth alloy target for forming a thin film,
A transition metal-rare earth alloy powder having a smaller amount of transition metal than the target component is produced by melting and crushing, and the alloy powder is mixed with the transition metal powder remaining for the target component, and then molded and sintered. Because of this, it is possible to manufacture plate-shaped alloy targets used in sputtering equipment, etc. using powder metallurgy techniques, and it is possible to sufficiently maintain a predetermined target shape, and it is also possible to use rare earth powder when manufacturing alloy targets. Since the transition metal powder is used as a binder between the powders, it is possible to significantly increase the purity of the alloy target, and at the same time, it is possible to obtain a highly dense target. This method has a very excellent effect in that it is possible to manufacture a high-strength alloy target without contamination.

Patent applicant: Daido Steel Co., Ltd. Representative Patent Attorney Yutaka Shio

Claims (1)

[Claims] (1) When producing a metal-local earth alloy target for bend forming, a transition metal-rare earth alloy powder having a smaller amount of transition metal than the target component is produced by melting and pulverizing, and A method for producing an alloy target for forming a thin film, comprising mixing the powder and the remaining transition metal powder with respect to the target components, and then molding and sintering the mixture.