JPH0790565A - Composite target for magnetron sputtering and its production - Google Patents

Abstract

PURPOSE:To minimize the consumption of the element of noble metal such as platinum and to reduce a film forming cost with respect to a target to be used in magnetron sputtering by forming a thin film (Pt-contg. Co alloy thin film of magnetic recording medium, etc.) contg. the expansive element. CONSTITUTION:This composite target consists of a sintered alloy layer 11 (CoCr alloy, CoCrNiTa alloy, etc.) having a specified chemical composition and a rod member 12 (Pt, etc.) embedded in the sintered alloy layer and having a specified chemical composition. The rod material 3 is positioned in a sputtering discharge concentrated region E' and dispersedly arranged in its peripheral direction in the sintered alloy layer 11 at regular intervals, and the sintered alloy layer 11 and the rod material 12 are joined and integrated by solid-phase welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces the cost of depositing an alloy thin film containing an expensive element such as Pt as a target for magnetron sputtering, especially as a magnetic recording film (magnetic film) of a metal thin film type magnetic recording medium. And a manufacturing method thereof.

[0002]

2. Description of the Related Art In a magnetic recording medium such as a magnetic disk, a magnetic drum, a magnetic sheet, a magnetic tape, etc., a magnetic recording film (magnetic film) is made of CoCr, CoN in order to meet the demand for high density recording.
Metal thin film magnetic recording media formed of Co-based ferromagnetic alloys such as i, CoCrNi, and CoCrTa have become the mainstream in place of the conventional coating type magnetic recording media. The demand for high-density recording in the magnetic recording field is increasing, and in recent years, in response to this demand, Pt and the like have been added to the above Co alloy as a magnetic film material for improving coercive force, squareness, noise characteristics and the like. Added CoCrPt, CoNiPt, CoCrTaPt
Have been developed, and their practical application has been attempted. As a method for forming various thin films such as the above magnetic film, magnetron sputtering is capable of forming alloy thin films having a complicated composition with good reproducibility, suppressing the temperature rise of the substrate during the sputtering process, and performing sputtering. It is carried out as an industrial film forming method that can increase the speed and is excellent in mass productivity.

Targets used in magnetron sputtering are roughly classified into coaxial type and planar type. In both cases, the magnetic field of a magnet arranged on the back surface of the target and the voltage applied to the target cause the vicinity of the target surface. An orthogonal electromagnetic field is formed in the area, Ar ions in the plasma are trapped in the area orthogonal to the electromagnetic field, and sputter discharge is concentrated and generated there. The concentrated area of the sputter discharge due to the orthogonal electromagnetic field is the target 10 'as shown in FIG.
A ring-shaped locus surrounding the center of the plate surface is drawn along the surface of the target, and the target is excavated in a groove shape in the area E ′, and erosion E occurs as shown in FIG. The recess depth of the erosion E increases as the sputtering time elapses ((1) to (3) in the same figure). If the surface of the target 10 ′ has a non-uniform shape due to an increase in erosion E accompanying the progress of sputtering, it may cause a decrease in sputtering efficiency and a decrease in the homogeneity of the thin film formed on the substrate. When the erosion E progresses to a certain extent, the residual material of the target is discarded and replaced with a new target.

[0004]

In the magnetron sputtering target, sputter discharge is concentrated in the region orthogonal to the electromagnetic field and the erosion E progresses as described above, so that it is effectively used for forming a thin film. It is limited to a small part, and most of it is unused and must be discarded as a residual material, so its effective utilization rate is extremely low. In the coaxial type target, the magnet in the target is driven to shift the orthogonal region of the electromagnetic field to expand the erosion range and reduce the amount of residual material. No measures can be adopted. As described above, in the field of metal thin film magnetic recording media, attempts have been made to put a Co alloy target containing Pt or the like as a magnetic film material into practical use, and the platinum alloy target is extremely expensive. However, the extremely low effective utilization rate of the target as described above increases the film formation cost and is a major factor that hinders the practical use of the magnetic recording medium. In view of the above, the present invention provides a target for magnetron sputtering capable of economically forming a thin film having a desired chemical composition while minimizing the amount of expensive elements used, and a method for producing the same. It is a thing.

[0005]

A magnetron sputtering target of the present invention comprises a sintered alloy layer having a predetermined chemical composition and a rod material containing a platinum group element embedded in the sintered alloy layer. The rods are located in the sputter discharge concentration region and dispersed in the sintered alloy layer at regular intervals in the circumferential direction, and the rods and the sintered alloy layer are bonded and integrated by solid-phase bonding. It is characterized by becoming. The target for magnetron sputtering of the present invention is to fix a plurality of rods containing a noble metal element such as platinum in a predetermined position in a metal capsule, fill a metal powder having a predetermined chemical composition, and degas and hermetically seal. In addition, it is manufactured by hot isostatic pressing under hydrostatic pressure.

[0006]

In the magnetron sputtering of the target of the present invention, a thin film is formed by sputter evaporation of the sintered alloy layer and the bar material. The chemical composition of the thin film to be formed is controlled arbitrarily and accurately by the chemical composition of each of the sintered alloy layer of the target and the bar, and the area ratio of the two in the sputter discharge region. Pt-containing C on the substrate of the magnetic recording medium
In sputter film formation for forming an o alloy thin film, it is not necessary to use an expensive Pt-containing alloy for the entire target,
With the t-containing composition, a Pt-containing Co alloy thin film having a desired composition is formed by using the minimum necessary amount of Pt.

The present invention will be described in detail below. FIG. 1 shows an example of the target of the present invention [FIG.
Is an external perspective view and (2) is its II cross-section). Reference numeral 11 is a sintered alloy layer, and 12 is a bar. The rods 12 are located in an annular region E ′ where sputter discharge is concentrated and embedded in the sintered alloy layer 11 at regular intervals in the circumferential direction. The bar 12 is a cast product, a plastically processed product by rolling, forging, or the like, or a sintered product.

The chemical composition of the sintered alloy layer 11 and the bar 12 is appropriately set according to the chemical composition of the thin film to be sputter-deposited. The magnetic film of the magnetic recording medium is made of Pt-containing C
As a target formed of an o alloy, for example, the rod 12 is Pt, and the sintered alloy 11 is an alloy of other elements (CoCr, CoNi, CoTa, CoCrTa, C).
oCrNiTa or the like). The rod may be an alloy of Pt and other elements (for example, PtCo alloy, PtNi alloy, PtCrTa alloy, etc.), and the distribution of the constituent elements of the rod and the sintered alloy and the design of the composition thereof are arbitrary. .

By magnetron sputtering using the target 10 composed of the rod 12 and the sintered alloy layer 11, for example, Cr is 6 to 17% and Pt is 1 to 15 in atomic%.
%, CoCrPt alloy thin film consisting of the balance Co, 1 or 2 to 1 to 38% of Ni or Ta (total amount in the case of two kinds composite), Pt 1 to 15%, CoN consisting of the balance Co
i (Ta) Pt alloy thin film, Cr 6 to 17%, Ni or Ta 1 type to 2 type 1 to 38% (total amount in the case of Ni and Ta composite), Pt 1 to 15%, balance CoCrNi (composed of Co) Ta) Pt alloy thin film, etc. can be formed. Of course, the composition of the thin film formed is not limited to that illustrated above, and the chemical composition of the sintered alloy layer 11 and the rod 12 and the cross-sectional diameter and the number of embedded rods 12 embedded in the sintered alloy layer 11 (sputtering). The volume ratio of the sintered alloy layer 11 and the rod 12 in the discharge region E ′ can be controlled arbitrarily and accurately.

The distribution of elements to the sintered alloy layer 11 and the bar 12 and the chemical composition thereof are not limited to the example in which an expensive element such as a noble metal element such as platinum is used as a constituent element of the bar 12. For example, it is disadvantageous in the manufacturing process to manufacture the target 10 containing all the elements constituting the thin film as one alloy, for example, the process is complicated, and it is difficult to secure the target quality (contamination of constituent elements, deterioration of yield). Etc.), the constituent elements are divided into the sintered alloy layer 11 and the bar 12, and the two members are combined to obtain a predetermined composition while avoiding a disadvantage in the manufacturing process. A target having can be configured.

The target 10 of the present invention is preferably manufactured by a hot isostatic pressing method (HIP sintering method). H
According to the IP sintering method, the sintered alloy layer 11 is highly densified, and the interface between the sintered alloy layer 11 and the rod 12 is brought into a surely bonded state by solid-phase bonding, and the rod 12 is targeted. It can be configured to be accurately arranged and fixed at a predetermined position in the sputter discharge concentration region.

FIG. 2 shows an example of manufacturing the target of the present invention by the HIP sintering method. C is a capsule (a container of mild steel, stainless steel, etc.), 11 'is a sintered alloy powder,
Rods (Pt rods or the like) are dispersed and fixed at predetermined positions in the capsule C and fixed (welding or the like), and the sintering raw material powder 11 ′ is filled around the rods 12. The rod 12 is a member obtained by machining a cast material having a predetermined chemical composition, a plastically worked material such as rolling or forging, or a sintered material to a predetermined size by machining. The sintering raw material powder may be a mixed powder in which a plurality of kinds of metal powders are mixed and kneaded in a ratio of a predetermined component composition, but in order to avoid non-uniformity due to a difference in specific gravity of the mixed powders. It is preferable that the powder is an alloy powder containing predetermined constituent elements. Further, as the powder, a rapidly solidified fine powder (for example, a particle size of 22 mesh or less) obtained by subjecting a molten alloy to an atomizing treatment is
Segregation of B, Ta, etc., which has a low solid solubility limit, is also slight, and it is suitably used as a powder with good homogeneity.

A capsule 12 has a rod 12 and a sintering raw material powder 1
After filling 1 ', the inside of the capsule C is vacuum-sealed via the deaeration pipe D. In this case, if vacuum degassing is insufficient,
In the sputtering process of the obtained target, gas such as nitrogen and oxygen remaining in the target causes abnormal discharge, so that the vacuum sealing is preferably about 0.1 mmHg or less. The hot isostatic pressing process after vacuum sealing has a temperature of 800.
~ 1250 ° C, pressure: 500-2000Kgf / cm
^2. Holding time: Achieved successfully under the condition of 0.5 to 4 Hr, high density with relative density of about 98% or more can be ensured, and the interface between the sintered alloy layer 11 and the rod-shaped body 12 to be formed. Enhancing the joint is ensured. The capsule C is removed by machining the sintered product obtained through the above process by machining.
The target 10 is obtained by finishing to a predetermined shape size.

[0014]

【Example】

[1] Production of Target: Capsule C as shown in FIG.
Weld the bar 12 to (made of mild steel) by welding,
After the sintering raw material powder 11 'is filled, it is degassed and hermetically sealed, subjected to hot isostatic pressing (HIP processing), and subjected to machining after sintering to prepare a target. (1) Raw material powder: Co alloy atomized powder (particle size 22 mesh under) Component composition (Wt%) Cr 8, Ni 4, Ta 10, C
o Bal. (2) Bar material: Pt bar (purity 99.99%), diameter 10 m
m. (3) Vacuum sealed: 0.08 mmHg. (4) Sintering conditions: temperature 1000 ° C, pressure 1000 kgf /
cm ² , holding time ² Hr.

(5) Test target shape / size: HIP
After the treatment, the capsules are removed by machining to remove the capsules and form a composite sintered body composed of the sintered alloy layer 12 and a rod (plate-shaped body, plate thickness 40 m
m) is taken out and subjected to machining to obtain a plurality of rectangular plate type targets shown in FIG. Size (mm): 130 × 500 × 10. Distribution of rods: distributed along the center line of the substantially rectangular annular region, which is the sputter discharge concentration region, at equal intervals of 20 mm.
The area ratio of the bar material in the sputter discharge concentrated region (bar material / sintered alloy) is 7%.

[2] Sputter deposition test of magnetic film of magnetic recording medium Using the above target as a target for forming a magnetic film of a magnetic recording medium (in-plane anisotropic magnetic disk), an aluminum alloy plate (nonmagnetic) was formed by magnetron sputtering. Film thickness as a film
20 μm Ni-P electroless plating film and a Cr film with a film thickness of 1000 Å are laminated to form a base film for the magnetic layer).
A NiTaPt alloy thin film (film thickness 600Å) was formed. Sputtering conditions: atmosphere 1 × 10 ⁻² Torr Ar gas, substrate temperature 250 ° C., substrate bias voltage −150V.

FIG. 3 shows the occurrence of erosion E in the sputter discharge concentrated region of the target. As the sputtering progresses, the erosion E becomes deeper with the bar 12 as the center, and the bar 12 is effectively used for sputtering film formation. FIG. 4 shows a magnetic film (CoCrNiTaP) formed on the substrate by the above sputtering.
With respect to the composition of (t alloy), the temporal change of the Pt content is shown. From the figure, from the beginning of using the target,
Until the end of its life, the composition of the magnetic film to be formed hardly changes, and the magnetic film having a predetermined alloy composition is stably formed as in the case of using a target made of a Pt-containing Co alloy. I understand.

[0018]

Since the target of the present invention has a composite structure of a sintered alloy layer and a bar, it can be formed into a thin film containing an expensive element such as a platinum group element by sputtering, for example, the magnetic property of a magnetic recording medium. When a Co alloy thin film containing Pt or the like is formed as a film, the target has a composite structure of a rod material such as Pt and a sintered alloy layer, so that the amount of expensive elements used can be minimized. It is possible to economically form a magnetic thin film having a predetermined chemical composition while suppressing the amount to the limit, and to enhance the practical value of the magnetic recording medium. Further, the present invention is not limited to a target for forming a thin film containing an expensive element by sputtering, and for example, a target may be manufactured as an alloy containing all of the elements necessary for forming a thin film. When the process is complicated or it is difficult to secure the target quality (contamination of alloy components, prevention of yield reduction, etc.), the constituent elements are divided into a sintered alloy layer and a bar, and both are combined. With this configuration, the target manufacturing process can be simplified, the cost can be reduced, the target quality can be improved, and the target quality can be improved by improving the quality of the sputtered thin film. To do.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a target of the present invention (FIG. 1 (1): external perspective view, FIG. 2 (2) II sectional view).

FIG. 2 is a cross-sectional explanatory view of a method for manufacturing a target of the present invention by a hot isostatic pressing method.

FIG. 3 is a cross-sectional view showing the generation state of erosion of the target of the present invention in magnetron sputtering.

FIG. 4 is a graph showing an example of composition variation of a thin film formed using the target of the present invention.

FIG. 5 is a perspective explanatory view showing a sputter discharge concentrated region on a target surface in magnetron sputtering.

FIG. 6 is a cross-sectional explanatory view showing erosion of a conventional target in magnetron sputtering.

[Explanation of symbols]

10, 10 ': Target, 11: Sintered alloy layer, 12:
Bar material, E ': Sputter discharge concentrated area, E: Erosion. C: Capsule, 11 ': Sintering raw material powder.

[Procedure amendment]

[Submission date] December 21, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

In the magnetron sputtering target, sputter discharge is concentrated in the region orthogonal to the electromagnetic field and the erosion E progresses as described above, so that it is effectively used for forming a thin film. limited Ku portion, remains largely unused, it is inevitable to waste as surplus material, thus its effective utilization have markedly low. In the field of metal thin film type magnetic recording medium as before mentioned, practical application of the Co alloy target containing Pt such as a magnetic film material also been attempted, the platinum-based alloy target are very expensive. However, the extremely low effective utilization rate of the target as described above increases the film formation cost and is a major factor that hinders the practical use of the magnetic recording medium. In view of the above, the present invention provides a target for magnetron sputtering capable of economically forming a thin film having a desired chemical composition while minimizing the amount of expensive elements used, and a method for producing the same. It is a thing.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C23C 14/35 Z 8414-4K G11B 5/85 C 7303-5D H01F 41/18 (72) Inventor Masahiko Yasui 1-247 Shikitsuhigashi Naniwa-ku Osaka City Kubota Co., Ltd.

Claims (2)

[Claims] 1. A sintered alloy layer having a predetermined chemical composition for forming a magnetic recording layer of a magnetic recording medium by sputtering.
It consists of a rod material containing a precious metal element such as platinum embedded in the sintered alloy layer, and the rod material is located in the spatter discharge concentrated region and is a sintered alloy with a certain interval in the circumferential direction. A composite target for magnetron sputtering, wherein the bar and the sintered alloy layer are dispersed and arranged in a layer, and the rod and the sintered alloy layer are bonded and integrated by solid phase bonding. 2. A plurality of rods containing a precious metal element such as platinum are fixed at predetermined positions in a metal capsule, and
The method for producing a composite target for magnetron sputtering according to claim 1, wherein a metal powder having a predetermined chemical composition is filled, degassed and hermetically sealed, and hot isostatic pressing is performed.