JPH05247641A - Target member and manufacture therefor - Google Patents

Abstract

PURPOSE:To manufacture a magnetic film with uniform magnetic characteristics, in a target member used for manufacturing the magnetic film for magnetic recording by a sputtering method. CONSTITUTION:The target member is formed to a sintered compact whose composition is uniform and relative density is >=98%, from the alloy which consists of 4-18% by atomic % of at least >= one kind among Cr, Mo and W, 0.1-8% of >= one kind among V, Nb, Ta, Ti, Zr, Hf and Ru and the balance Co. In the case that the target member is produced, <=32 mesh alloy powder in the particle size which is produced by a rapid solidification method is filled in a metallic container and sealed and then sintered under pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a target member for forming a magnetic film mainly composed of Co for magnetic recording by a sputtering method, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Co-Ni,
Co-Cr or Co-Ni-Cr has been conventionally used industrially. In recent years, Co-Ni, Co-Cr, or Co-Ni-C has been demanded due to the demand for reducing noise caused by the magnetic film and increasing the coercive force of the sputtered film (magnetic film).
Alloys obtained by adding Ta or Pt to r have come to be used for magnetic films, and are now the mainstream of recording media (see Japanese Patent Laid-Open No. 1-133217). On the other hand, the amount of Ta contained was 1 atom% in the initial stage, but recently, it has been increasing to 2 atom% or more to increase the coercive force. Also, the Pt amount is
It is contained in an amount of 5 to 15 atom% for increasing the coercive force. The target member used for forming this sputtered film is conventionally
After melting and casting, it was formed as it is, or hot or cold worked into a thin plate, and then processed and sampled.

[0003]

[Problems to be Solved by the Invention] Industrial melting of alloys,
In casting, there is a difference in composition between the outer peripheral portion and the central portion of the steel ingot which is solidified by contacting the mold. CoCr
In the Co-Cr-Ta ternary alloy in which Ta is added to Ta, Ta is enriched in the central portion of the ingot from the average value of the entire alloy, and Co ₂ T
a segregates microscopically. Further, when the Cr concentration increases, the segregation of Cr proceeds, and a Cr-enriched CoCr layer is formed on the outer peripheral portion of the steel ingot. In a Co-Cr-Pt-B quaternary alloy, CoP
Different phases such as t and CoB will occur. Co-Cr-Mo
-Ta-Pt-B6 ternary alloy further has TaB and CrMo.
And so on. As described above, since various different phases occur in the multi-component alloy, uniform rolling may be difficult or warpage may occur in the rolled thin plate during hot working such as rolling of these steel ingots. It was In addition, since the composition of the prepared target members is also non-uniform, there is a problem that the sputtered film obtained by using these target members does not have uniform magnetic characteristics. An object of the present invention is to provide a target member that produces a sputtered film having uniform magnetic properties and a method for manufacturing the target member.

[0004]

The target member of the present invention is mainly composed of Co and contains 4 to 18% of at least one of Cr, Mo and W, and among V, Nb, Ta, Ti, Zr, Hf and Ru. At least one of them is 0.1 to 8%, the balance is an alloy consisting essentially of Co and unavoidable impurities, and is composed of a sintered body having a uniform composition and a relative density of 98% or more. Further, Co is the main component and Pt is 0.5 to 16%,
4-18% of one or more of Cr, Mo and W, V,
0.1 to 8% of at least one or more of Nb, Ta, Ti, Zr, Hf, and Ru, the balance substantially consisting of Co and unavoidable impurities, or 0.5 to 16 Pt containing Co as a main component. %, One or more of Cr, Mo and W is 4 to 18%, V, Nb, Ta, Ti, Zr, Hf
And at least one or more of Ru is 0.1 to 8%,
0.1 to 10 of one or more of B, C, Si and Al
%, The balance consisting essentially of Co and inevitable impurities, and composed of a sintered body having a uniform composition and a relative density of 98% or more. The manufacturing method of the target member of the present invention,
An alloy powder having a particle size of 32 mesh or less, which is composed of the alloy composition described above, is filled in a metal container and then pressure-sintered to have a uniform composition and a relative density of 98.
A target member having a percentage of at least 100% is manufactured.

The target member of the present invention is mainly composed of Co, and at least 1% or more of Cr, Mo and W is 4 to 4 in atomic%.
18%, V, Nb, Ta, Ti, Zr, Hf, and R
At least one or more of u is 0.1 to 8%, Pt is 0.5 to 16%, and one or more of B, C, Si and Al is 0.1 to 10%. This is because if the total amount of Mo and W exceeds 18%, the alloy steel ingot is easily cracked during hot working and is not suitable for manufacturing a target member. Further, the total amount of Cr, Mo and W is 4
This is because the prepared sputtered film does not have sufficient magnetic characteristics when the content is less than%. V, Nb, Ta, Ti, Zr, Hf
If the total amount of Ru and Ru exceeds 8%, a different phase will precipitate during rolling of the steel ingot. This is because when the amount of Pt exceeds 16%, warpage occurs in the target member in the grinding process for finishing the surface of the target member. This is because when the amount of Pt is 0.5% or less, the effect of addition on the magnetic properties is not recognized. This is because if the total amount of B, C, Si and Al exceeds 10%, the steel ingot is likely to crack during processing.

A feature of the above manufacturing method is to use an alloy powder having a predetermined composition manufactured by a rapid solidification method such as a gas atomizing method. That is, since this powder has a high cooling rate for solidification, it has a uniform composition with suppressed segregation. Therefore, the target member obtained by using this has a uniform composition on both the surface of the target member and the central portion of the plate thickness, unlike those obtained by the conventional melting or casting method.
As the rapid solidification method, a known powder manufacturing method such as a vacuum atomizing method, a rotating roll method, and a rotating electrode method can be applied in addition to the above-described gas atomizing method. In the rotating roll method, the rotating electrode method, etc., it is desirable that the atmosphere is a vacuum or an inert gas atmosphere in order to prevent the alloy from being oxidized. Among the rapid solidification methods, the gas atomization method is preferable because it is easy to form a spherical powder that can obtain a high tap density and is advantageous in production cost. Among the alloy powders obtained by the above rapid solidification method, those having a particle size of 32 mesh or less are used. The reason why the particle size of the powder is 32 mesh or less is that the homogeneity of the composition of the supersaturated solid solution becomes poor at the time of sintering. Next, this alloy powder is pressure-sintered to obtain a sintered body having a relative density of 98% or more. The relative density of 98% or more is
This is because if bubbles are present at a density lower than this, abnormal discharge will occur during the sputtering operation.

As a method of pressure sintering, hot isostatic pressing (HIP), hot pressing, hot pack rolling, forging, etc. can be applied, but in order to obtain a high density of 98% or more, H
IP is most desirable. This HIP has a temperature of 1000 to 1
It must be carried out under the conditions of 250 ° C. and a pressure of 500 atm or more. Here, the upper limit of the temperature is 1250 ° C.
This is because the Co—Pt eutectic temperature is 1276 ° C., and a melt is generated in the Pt-rich portion in the powder microscopically. On the other hand, the lower limit of the temperature is set to 1000 ° C., because the sintered density does not rise to 98% or more below this. Also,
The pressure is set to 500 atm or more because if the pressure is less than 500 atm, it is difficult to set the relative density of the sintered body to 98% or more. Furthermore, when hot working is performed after pressure sintering by hot isostatic pressing or the like, the relative density is improved, and a target member with more stable sputtering characteristics can be obtained.

[0008]

【Example】

(Example 1) 12Cr-4Pt-2V-3B in atomic%,
A synthetic powder with the balance Co composition was produced by gas atomization.
Then, this powder is classified to obtain powder of 32 mesh or less.
kg was weighed. This powder was filled in a mild steel can and degassed,
After sealing, hot isostatic press at 1200 ° C, 500a
Sintering was performed at tm. Next, this box was finished by hot rolling to have a thickness of 8 mm, and iron sheets on both sides were peeled off to collect a 6 mm plate material. On the other hand, in atomic%, 12Cr-4Pt-2
After vacuum melting V-3B and the balance Co alloy, 30
6 kg of steel ingot is produced by hammer slab and hot rolling
When a plate material of m was produced, it cracked, and 200 × 2
It was not possible to obtain a plate material having a size of 00 mm or more. Next, a target member having a thickness of 5 mm and a diameter of 102 mm was sampled from each of the plate materials manufactured by the powder method and the conventional melting method. Using this target member, a pure Cr underlayer on soft glass substrate on which the 0.1μm deposited, high-frequency output 300w, Ar operating pressure ³ × 10 ^- 3 t
A film having a thickness of 50 nm was formed under the condition of orr, and the coercive force of the film was measured with a vibration magnetometer.

Table 1 shows E of the target member surface layer and the central portion.
The analysis value (at%) of the composition by PMA and the magnetic value of the sputtered film corresponding to the position of the target member are shown. Table 1
As can be seen, the target member produced by the powder method has no change in composition on the surface and the center of the plate thickness, and the magnetic value of the film formed by sputtering shows almost no change. On the other hand, the target member manufactured by the conventional melting method has a composition in which the surface layer contains slightly more Cr and less Pt than the average value. Further, there is a portion where the different phase of CoPt extends linearly in the rolling direction due to hot working. It was also known that the coercive force of the sputtered film was different between the surface of the target member and the center of the plate thickness.

[0010]

[Table 1]

(Example 2) CoCrPtVB was further added as a material alloy for the target produced in Example 1 above.
When a target to which 2% of o was added was prepared in the same manner as in the above-described example and the same measurement as in Table 1 was performed, the result was almost the same as that in the example of the present invention. Cr12at%, V
Table 2 shows a target made of 2 at% of at least one of Nb and 2 at%, and the balance of Co being substantially the same as in the above-mentioned Example and measured in the same manner as in Example 1. From Table 2, it can be seen that the target member manufactured by the powder method has no change in composition on the surface and in the center of plate thickness, and there is little change in the characteristics of the magnetic film formed by sputtering.

[0012]

[Table 2]

[0013]

As described above, Co is the main constituent, and at least one of Cr, Mo and W is 4 to 4 atomic%.
18%, V, Nb, Ta, Ti, Zr, Hf and Ru
0.1 to 8% of at least one of them, the remaining Co target member, and a target member of 0.5 to 16% of Pt, and 0.1 to 0.1% of B, C, Si and Al. When the target member containing 10% of the powder is manufactured by the powder method, the composition change in the target member is smaller than that of the target member manufactured by the conventional melting method, and the fluctuation of the magnetic characteristics of the sputter-produced film is small. Was given. It is extremely advantageous for a magnetic recording medium to obtain a sputtered film having a constant magnetic characteristic, and the target member of the present invention by the powder method and the manufacturing method thereof have a remarkable industrial effect.

Claims (4)

[Claims] 1. A target member for sputtering, the composition of which is at.
4-18% of one or more of o and W, V, Nb, T
0.1% to 8% of at least one of a, Ti, Zr, Hf, and Ru, the balance being an alloy essentially consisting of Co and inevitable impurities, having a uniform composition and a relative density of 98%.
A target member, which is a sintered body as described above. 2. In a sputtering target member, the composition is atomic%, Co is the main component, Pt is 0.5 to 16%, one or more of Cr, Mo and W is 4 to 18%, V and Nb. , Ta, Ti, Zr, Hf and Ru of 0.1 to 8%, and the balance consisting essentially of Co and inevitable impurities, and having a uniform composition and a relative density of 98% or more. A target member, which is a united body. 3. A target member for sputtering, the composition of which is atomic%, 0.5 to 16% of Pt with Co as a main component, 4 to 18% of one or more of Cr, Mo and W, V and Nb. , Ta, Ti, Zr, Hf, and Ru, 0.1 to 8%, B,
0.1-10% of one or more of C, Si and Al,
A target member, characterized in that the balance is an alloy substantially composed of Co and inevitable impurities, and is a sintered body having a uniform composition and a relative density of 98% or more. 4. A method for manufacturing a target member according to claim 1, claim 2 or claim 3, wherein the alloy according to claim 1, claim 2 or claim 3 has a grain size of 3
A method for producing a target member, comprising using an alloy powder produced by a rapid solidification method of 2 mesh or less, filling the alloy powder in a metal container, and encapsulating the alloy powder, followed by pressure sintering.