JPS63171877A - Composit target material - Google Patents

Abstract

PURPOSE:To obtain a composite target material having excellent corrosion resistance for magneto-optical disks, by dispersing an intermetallic compd. or solid soln. of a corrosion resistance improving metal and metal for constituting a matrix consisting of a rare earth metal and transition metal uniformly into said matrix. CONSTITUTION:The matrix is constituted of the rare earth metal such as Nd, Gd, Tb, Dy, Ho, Er, or Tm and the transition metal such as Fe, Co or Ni. On the other hand, the intermetallic compd. or solid soln. is formed of the metal such as Ti, Cu, Zr, Ge, Si, Sn, Pb, In, Cr, Mo, W, Nb. Ta, Pt, Rh, or Re having an effect of improving the corrosion resistance and >= kinds of the metals constituting the above-mentioned matrix. The above-mentioned intermetallic compd. or solid soln. is then dispersed uniformly at about 1-20atom.% into the above-mentioned matrix, by which the composite target material is obtd. The matrix preferably constituted of the eutetic structure of the rare earth metal and the transition metal and the metal structure which is the same as or different from said constituting metal components.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composite target material suitable for producing a magneto-optical recording thin film by sputtering.

[Conventional technology]

A combination of rare earth metals and transition metals has been reported as a film composition for magneto-optical disks.

For example, τb-IF m, Tb-F e -Oo,
G d-T b -IP e,G(1-τb-7m-O
o, T b-Oo, T b-D y-F e -0
Examples include 0%I)7-F and %Q(1-'O).

Recently, studies have been made to improve the corrosion resistance of films for magneto-optical disks such as those described above. For example, T1
%OQ, Zr%Ge.

sl, sn%P'b, engineering! L, Cr, Mo, W,
Nb, Ta, Pt.

A method has been proposed in which nine metal chips selected from Rh and Re are placed and sputtered to form a film (
For example, JP-A-40-21/! (See Publication No. 140).

[Problem that the invention seeks to solve]

However, in such a sputtering method, the composition distribution within the disk surface becomes large, and when sputtering is performed for a long time, the composition of the film formed within the disk surface changes. As a result, it is difficult to improve corrosion resistance over the entire disk surface, and a better method has been sought.

cMeans for Solving the Problems] In view of the above problems, the inventors of the present invention have made extensive studies, and as a result, the present inventors have developed mr! The present invention was achieved based on the knowledge that uniformly dispersing one compound or a solid solution significantly improves the compositional distribution of a film formed within the disk surface after sputtering, and improves the corrosion resistance over the entire metal region of the disk surface.

]) 7% T in a matrix consisting of a rare earth metal selected from the group consisting of Ho, Ir and Tm and a transition metal selected from the group consisting of We, 00 and Ml.
i @ ' us Z r s G 8 s ' i
% B"% ' 6%In, Or, MO, W, M
The target material is a composite target material formed by uniformly dispersing an intermetallic compound and/or solid solution of one or more metals constituting a matrix and a metal selected from the group consisting of: b, Ta, Pt%Rh, and Re.

The present invention will be explained in detail below.

In the present invention, T1 is used as a metal that is effective in improving corrosion resistance.
．． 0u1Zr, Go, sl, 8n, Pb, Eng n10r
, Mo, W, Wb, Ta, Pt, Rh, and one or more metals selected from R11 (hereinafter referred to as
%'ri, Ou%Zr, Ge, and Eii are particularly preferred from the viewpoint of corrosion resistance.

The composite target material of the present invention has Md%G (1%Tt+).

Dy% One or more rare earth metals selected from the group consisting of Ha, Kr and Tm (hereinafter abbreviated as "rare earth metals") and one or more selected from the group consisting of re, Oo and Ml forming an intermetallic compound and/or solid solution of the corrosion resistance improving metal and one or more metals constituting the matrix in a matrix consisting of a transition metal (hereinafter abbreviated as "transition metal"); Disperse this uniformly. It is thought that this uniformly dispersed structure eliminates the directionality in the flight of metal elements during sputtering, so that there is almost no in-plane compositional distribution of the film formed on the disk, and the corrosion resistance is improved over the entire disk surface.

The amount of the intermetallic compound or solid solution to be uniformly dispersed varies depending on the type of metal selected, but is usually 7-λ〇N atoms in the target material. If it is too small, there will be no effect of improving corrosion resistance, and if it is too large, the properties of the disk such as Kerr angle and holding force will deteriorate. Preferably it is 3 to 10 at%.

On the other hand, as mentioned above, the matrix is composed of rare earth metals and transition metals, but the structure is usually an intermetallic compound structure, a eutectic structure, an elemental metal structure, or a mixture of these structures. After sputtering.

Considering the uniformity of the total metal composition distribution within the disk plane, the matrix is preferably composed of a eutectic structure of a rare earth metal and a transition metal, and a metal structure that is the same as or different from the metal components constituting the eutectic structure. This is because the eutectic structure of rare earth metals and transition metals has a uniform and fine structure, and this uniform and fine structure gives directionality to the flight of the film-forming elements during sputtering. Since the surface of the sputtered alloy target material is flat, there is almost no in-plane composition distribution of the disk, and the in-plane composition of the disk does not change even if sputtered for a long time.

In this case, it is preferable to have a eutectic composition where there is a large amount of eutectic structure, but it does not necessarily have to be a eutectic composition, and it can also be used as a hypoeutectic composition or a hypereutectic composition in consideration of grindability, etc. It is sufficient if a eutectic structure is obtained. The amount of eutectic structure is io
Weight X or more, preferably λj weight plate. Also,
In addition to the eutectic structure, it contains a metal structure that is the same as or different from the metal components constituting the eutectic structure, but in order to utilize the fine and uniform structure of the eutectic structure, the amount thereof is 20% by weight or less, preferably 75% by weight. % or less is better.

A general manufacturing method for obtaining the above composite target material of the present invention will be explained.

In the combination of each metal constituting the desired composite target material, intermetallic compounds and/or
Or select a system and its composition that form a solid solution. Cast with that composition to obtain a mass of intermetallic compound and/or solid solution.

On the other hand, the metal structure is not particularly limited as long as it is formed to have a desired composition from an IJ lux rare earth metal and a transition metal. For example, when the matrix structure is an intermetallic compound structure of rare earth metals and transition metals, a lump is obtained by casting and alloying to obtain the desired composition. If the matrix is to have a single metal structure, powders of each element may be separately prepared and mixed to obtain the desired composition. Furthermore, in the case of forming a structure containing one eutectic structure, the eutectic composition of the rare earth metal and the transition metal is investigated from the equilibrium phase diagram, and the composition is blended and cast to obtain the eutectic composition. In this case, in order to obtain a uniform and fine eutectic structure, the cooling rate during casting is 0.07
It is preferable to obtain the lump by an arc melter method at a temperature of 11CdO,l''07 seconds or more.

ζ The thus obtained metal lumps may be pulverized by a conventional mechanical pulverization method. If mechanical pulverization is difficult, it is also possible to obtain powder directly from the molten metal by gas atomization or the like.

Grind it to about 7 to 000 m with a cutter mill equipped with rolling blades, and if further pulverization is required, use a vibrating mill, jet mill, etc. A crusher with a set of hammers or a set of rollers may be used as the coarse pulverizer, and in addition to the cutter mill, a ball mill, stamp mill, rod mill, etc. may also be used.

Note that active materials such as rare earth metals or their alloys can be crushed in an inert gas atmosphere in the case of a dry process, or in an atmosphere of allium, acetone, benzene, or carbon tetrachloride that does not contain moisture or oxygen in the case of a wet process. It is preferable to use a solvent such as , Freon or the like.

And/or the solid solution is preferably 1004m or less in order to ensure uniform dispersion.

The obtained powders and the like are blended to a desired composition and mixed uniformly.

Next, the powder is sintered and shaped to obtain a composite target material, which may be done by a conventional method. As an example of the hot press method, the powder is filled into a die whose inner surface is coated with a release agent such as boron nitride (Bli) under an inert atmosphere such as argon gas. Pressure sintering is performed in an inert gas such as gas or a vacuum atmosphere. Although the temperature varies depending on the pressure, it is suitably below the melting point of the powder. The preferable pressure is 1. If it is too large, leakage of the liquid phase and damage to the die and punch may occur.
kg/lyt? is preferred. The material of the die and punch is usually graphite, but heat-resistant steel or ceramics may also be used.
.

When using hot isostatic pressing as a sintering forming method,
For example, the powder is placed in an inert atmosphere such as argon gas,
After filling carbon steel and stainless steel into glass containers,
It is sealed while being evacuated, and then sintered under pressure using a hip device. The temperature is suitably lower than the hot press temperature described above. However, in the case of a glass container, the temperature must be higher than the transition point of the glass. The pressure is not particularly limited as long as the deformation of the container can be followed at the temperature, but it is usually less than 000 Icg/cIII. If it is too small, the deformation will be insufficient and high density will not be obtained.
~l! 00 to 4/crI is preferred.

Furthermore, in the case of the sintering method, cough powder is preformed into a predetermined shape using a hydraulic press or the like under an inert atmosphere such as argon gas, and then sintered in a sintering furnace. Is the atmosphere an inert gas?
There's a vacuum. The higher the temperature, the better (if using a hot press).

The sputtering conditions for obtaining a magneto-optical recording thin film, etc. using the composite target material of the present invention manufactured as described above may be a general method. For example, in order to prevent property deterioration due to oxygen contamination during film formation, the desired degree of vacuum attainment is /o
-” torr or less. Then, inject an inert gas such as argon gas to the desired pressure. The gas pressure is / #
j 0711 torr range, gas flow rate is /NN10
A range of 0eaa is appropriate.

Sputter power sources are mainly DC and high frequency.

High-frequency power supplies are used for sputtering, and are effective in removing impurities such as oxygen introduced during film formation and preventing deterioration of properties.

The substrate on which the film is formed may be glass, polycarbonate, epoxy resin, or the like.

〔Example〕

The present invention will be explained in more detail below by way of examples.

Example 1 A composite target material of Tb:IFe:τ1=λj:gz=io (atom X) was manufactured. That is, first jl-IP
Tl:Fe; l:λ to form an intermetallic compound of e
(atomic ratio) was cast using the arc melter method to obtain a lump of intermetallic compound.

On the other hand, as a matrix, %71) Gold JL Fe metal was blended to a desired composition and a cast ingot was obtained by an arc melter method.

Each metal lump was crushed using a show crusher, cutter mill) in an argon gas atmosphere.

A powder of 1100 ta or less was obtained. Blend and mix each powder so that it has the above composition, fill it into a steel capsule, and then
Sintering was carried out using a hot isostatic press at 100 degrees Celsius and 1000 atmospheric pressures.

As a result of X-ray diffraction and KPMA observation, the structure of this sintered body showed that the Ti-Pa intermetallic compound was uniformly dispersed in the matrix.

This was processed into a diameter of 74.2 cm for sputtering and used as a target material. DC power supply using the target material, 300
Sputtering was carried out using a magnetron method at an argon gas pressure of 10 torr for W%j minutes. A glass disk with a diameter of 300 mm was used for the film formation. By analyzing the obtained large film composition at Jam intervals using the fluorescent xfiI method), the film composition distribution within the disk plane was investigated. The results are shown in Table/.

For comparison, a test was conducted under the same conditions as above except that a pure T1 metal chip 11 was placed on the surface of the g'r'b-Pa alloy target material and the area ratio was made to have the above composition. The results are shown in Table 7.

ff/ Disc in-plane film composition distribution (T1: atomic %
)Example Tb:? e:Qo:Ge=JO:40:10:10 (
fi.

%) to manufacture composite target materials. That is, first Go
-G.Nia 6w/ to form an intermetallic compound of Fe
:J (atomic ratio) was cast by an arc melter method to obtain a lump of an intermetallic compound.

On the other hand, to make the matrix a eutectic structure.

A eutectic structure mass with a composition of Tb:IFez72:al (atomic %) was obtained by an arc-melter method.

Each metal lump was crushed using a show crusher and a cutter mill in an argon gas atmosphere to obtain a powder of 100 μm or less. In addition, l1le powder below 1003 m, C
o powder was prepared.

After blending and mixing the above powders to obtain the desired composition and filling the powders into a graphite die, the intermetallic compound of Ge-Fe was uniformly dispersed in the matrix. This was processed to have a diameter of 76 mm for sputtering, and the target material was bound to 9.

Using the target material, sputtering was performed using a magnetron method using a DC power supply, 1 minute of argon gas pressure, and several mtorr of argon gas. The disk to be deposited has a diameter of JOOw.
All m glass was used.

The resulting composition was analyzed in the same manner as in Example 1. The results are shown in Table 2.

For comparison, sintering was performed under the same conditions as above, except that 06 metal powder was used instead of the Go-Fe intermetallic compound. The structure of this sintered body is determined by X-ray diffraction, EiPMA observation results,
M) Pure Ge gold jAll fabric was present in the ricks. The results of sputtering this sintered body in the same manner as above are shown in Table λ
Shown below.

Table 2 Disk in-plane film formation composition distribution (Gs: atom X) Example J Tb:ao:0r=J7:At:zO (Jjfi, child
) Composite target material yk is broken. That is, first 0r-
0r-00=j to form an intermetallic compound of 00
A lump of intermetallic compound was obtained by casting with an arc melter method with a composition of: J (i element ratio).

On the other hand, as a matrix, Tt) metal, G.

A cast ingot was obtained using an arc melter method so that the metal had the desired composition.

Each metal lump was crushed in an argon gas atmosphere using a show crusher and a cutter mill.

/00 tsm or less powder was obtained. The powders were blended and mixed to finally have the above composition, filled into a steel capsule, and then sintered in a hot isostatic press at 1000°C and 10DD atmospheric pressure.9.

The structure of this sintered body is determined by X-ray diffraction, IIIPM observation results,
Make sure that the KOr-Oo intermetallic compound in the matrix is uniformly dispersed.

Process the tore into a diameter of 76.2cm for sputtering.

It was used as a target material. Using the target material, DC power supply %10011%l1 minute, argon gas positive number + mtorr
, sputtering was performed using a magnetron method. A glass disk with a diameter of 300 square meters was used for film formation. The obtained film composition was analyzed in the same manner as in Example I. Results! ! Shown in 3.

For comparison, iJK shows the results of a test conducted under the same conditions as above, except that a pure Or metal chip was placed on the surface of a τ)-〇o alloy target material so that the 1 area ratio had the above composition.

! ! ! ! J Disk in-plane film formation composition distribution (□ r: atom X) Example HiroTb:Ga:Il'f:Zr=/J:/J:44:10
(atomic %) composite target material was manufactured. That is, first, Zr:F is used to form an intermetallic compound of Zr-IF@.
An intermetallic compound lump was obtained by casting using an arc melter method with a composition of .=Z:2 (atomic ratio).

On the other hand, to make the matrix a eutectic structure.

Each eutectic structure mass was obtained by the Arry-melter method with a composition of T he, ]Fe=72: J t (atom X) s Ga: ]Fs=j7:/J (atom X).

Each metal lump was crushed in an arbon gas atmosphere using a show crusher and a cutter mill to obtain powder of 100 μm or less. In addition, 1 powder of 1100 t1 or less was prepared.

Blend each powder to achieve the final desired composition.

After mixing and filling into a graphite die at 700°C, the intermetallic compound of KZr-y was uniformly dispersed in the matrix.

This was processed into a diameter of 76.2 cm for sputtering and used as a target material. Using the target material, a DC power supply zoo
Sputtering was performed using a magnetron method at v% 3 minutes, argon gas pressure, and torr. The disk on which the film was formed was made of glass with a diameter of JOO.

The film composition was analyzed in the same manner as in Example 1, and the results are shown in Table 1.

For comparison, sintering was performed under the same conditions as above except that Zr metal powder was used. The structure of this sintered body was determined by X-ray diffraction, II
As a result of iPMA observation, a pure Zr metal structure was present in the matrix. This sintered body was sputtered in the same manner as above, and the results are shown in Table μ.

Table ≠ Disk in-plane film composition distribution (Zr: i-S) Example! A composite target material of T1+:Fe:C1u=Jj:47:#) (atomic %) was manufactured. That is, - First, to form a solid solution of Ou-Fa, Ou:F@z/:/(atomic ratio)
A solid solution lump was obtained by casting using the arc melter method with the following composition.

On the other hand, in order to make the matrix a eutectic structure, τb−ν・
A eutectic structure mass was produced by an arc melter method with a composition of =7 co:cot (atomic %).

Each metal lump was crushed in an argon gas atmosphere using a show crusher and a cutter mill to obtain a powder of 1005 m or less. In addition, ν powder of 100 μm or less was prepared.

Each powder was blended and mixed to have the above composition, filled into a steel capsule, and then sintered in a hot isostatic press at 600° C. and 10 DD atmospheric pressure.

The structure of this sintered body is the result of xm diffraction, IltPM observation,
w) Ωu-? e The solid solution structure was uniformly dispersed.

This was processed into a diameter of 76.2 cm for sputtering and used as a target material. Using the target material, a DC power source, 30
Sputtering was performed using a magnetron method at θW for 3 minutes, argon gas positive number 5 tories. A glass disk having a diameter of 3θθ■ was used for film formation. The obtained large film composition was analyzed in the same manner as in Example 1, and the results are shown in NZ.

For comparison, holes were sintered under the same conditions as above, except that KOU metal powder (instead of Ou-Fe solid solution) was used. The structure of this sintered body is the result of X-ray diffraction, )lm observation,! A pure Ou metal structure was present in the trix. This sintered body was sputtered in the same manner as above, and the results are shown in Table 7.

table! Disk in-plane film formation composition distribution (Ou: atomic ratio) [Effects of the invention] As described above, when the composite target material of the present invention is used, the uniformity of the composition distribution of the thin film obtained by sputtering is extremely improved, and therefore the thin film Since the corrosion resistance can be improved throughout, the present invention provides an industrially excellent target material.

Claims (2)

[Claims] (1) In the composite target material for magneto-optical disks, N
Ti, Cu, Zr, Ge
, Si, Sn, Pb, In, Cr, Mo, W, Nb, T
A composite target material formed by uniformly dispersing an intermetallic compound and/or solid solution of a metal selected from the group consisting of a, Pt, Rh, and Re and one or more metals constituting a matrix. (2) The matrix is composed of a eutectic structure of a rare earth metal and a transition metal, and a metal structure that is the same as or different from the metal components constituting the eutectic structure. composite target material.