Sputtering target and sputtering target assembly

Abstract

A sputtering target having: (1) Fe; (2) Pt; (3) one or more elements selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; in the sputtering target, the atomic ratio of (1) Fe and (2) Pt is 34-55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the total content of elements in (3) is 0.5-15 mol%, the remainder of (4) is an oxide, impurities are optionally and selectively included, the volume fraction of the oxide is 40 vol.% or more, and an SEM image having a field-of-view magnification of 3000 is used. And the average particle size of the oxide phase, which is calculated using ImageJ, is 4.0 [mu] m2 or less.

Description

Technical Field

[0001] The present invention relates to a sputtering target and a sputtering target assembly, and particularly to a sputtering target suitable for manufacturing a film for a HDD. Background Art

[0002] In the layers constituting a hard disk drive (HDD) using a perpendicular magnetic recording method, for example, materials based on ferromagnetic metals such as Co, Fe, and Ni are used, and composite materials consisting of ferromagnetic alloys such as Co-Cr, Co-Pt, Co-Cr-Pt, and Fe-Pt with Co and Fe as main components and non-magnetic inorganic materials are often used in the recording layer. From the viewpoint of high productivity, thin films of magnetic recording media such as hard disk drives are often produced by sputtering a sputtering target composed of the above materials.

[0003] In the manufacture of a sputtering target, generally, first, powders of raw materials are crushed and mixed to obtain a mixture, and the mixture is hot pressed to obtain a sintered body. Then, in order to increase the density of the sintered body, HIP (Hot Isostatic Pressing) processing is sometimes performed. The sintered body thus obtained is processed using a lathe to manufacture a target of a predetermined shape (Patent Documents 1, 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6030271

[0007] Patent Document 2: Japanese Patent No. 6305881 Summary of the invention

[0008] Problems to be solved by the invention

[0009] As mentioned above, a composite material composed of a ferromagnetic alloy such as Fe-Pt and a non-magnetic inorganic material is useful as a recording layer of an HDD. However, in order to produce such a recording layer, when a sintered body having a structure in which oxides are dispersed in a parent metal containing Fe and Pt is manufactured as a sputtering target, there is a problem that the sintered body having such a composition is brittle and cracks and breaks occur during the manufacturing process.

[0010] Therefore, an object of an embodiment of the present invention is to provide a sputtering target and a sputtering target assembly, wherein the sputtering target can satisfactorily suppress the occurrence of cracks and breakages in the manufacturing process.

[0011] Solutions for solving problems

[0012] The above-mentioned technical problems are solved by the present invention defined as described below.

[0013] 1. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the total content of the elements in (3) is 0.5 to 15 mol%, and the remainder of (4) is an oxide, optionally selectively containing impurities, the volume fraction of the oxide is 40 vol.% or more, and in the sputtering target, the average particle size of the oxide phase calculated by ImageJ using a SEM image with a field magnification of 3000 times is 4.0 μm 2 the following.

[0014] 2. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the total content of the elements in (3) is 0.5 to 15 mol%, and the remainder of (4) is an oxide, optionally selectively containing impurities, the volume fraction of the oxide is 40 vol.% or more, and in the sputtering target, the average perimeter of the oxide phase calculated using ImageJ using a SEM image with a field of view magnification of 3000 times is 11.7 μm or less.

[0015] 3. A sputtering target comprising: (1) Fe; (2) Pt; (3) one or more elements selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the total content of the elements in (3) is 0.5 to 15 mol%, and the remainder of (4) is an oxide, optionally selectively containing impurities, the volume fraction of the oxide is 40 vol.% or more, and the bending strength of the sputtering target is 300 MPa or more.

[0016] 4. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the total content of the elements in (3) is 0.5 to 15 mol%, and the remainder of (4) is an oxide, optionally selectively containing impurities, the volume fraction of the oxide is 40 vol.% or more, and in the sputtering target, an oxide phase is calculated using ImageJ using a SEM image with a field magnification of 3000 times, and the number average diameter of the equivalent circle diameter calculated by assuming the shape of the oxide of the oxide phase to be a circle is 1.3 μm or less.

[0017] 5. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the content of the elements of (3) is 0.5 to 15 mol% in total, and the remainder of (4) is an oxide, optionally containing impurities, the volume fraction of the oxide is 40 vol.% or more, and in the sputtering target, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measured area of ​​1261 μm 2 The number of particles having a circle-converted oxide diameter of 1 μm or less is 100 or more.

[0018] 6. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the content of the elements of (3) is 0.5 to 15 mol% in total, and the remainder of (4) is an oxide, optionally selectively containing impurities, the volume fraction of the oxide is 40 vol.% or more, and in the sputtering target, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measured area of ​​1261 μm 2 The number of particles having a circle-converted oxide diameter of 2 μm or less is 120 or more.

[0019] 7. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the content of the elements of (3) is 0.5 to 15 mol% in total, and the remainder of (4) is an oxide, optionally selectively containing impurities, the volume fraction of the oxide is 40 vol.% or more, and in the sputtering target, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measured area of ​​1261 μm 2 The number ratio of particles having a circle-converted diameter of the oxide of 1 μm or less is 60% or more.

[0020] 8. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from the group consisting of Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the content of the elements of (3) is 0.5 to 15 mol% in total, and the remainder of (4) is an oxide, optionally selectively containing impurities, the volume fraction of the oxide is 40 vol.% or more, and in the sputtering target, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measured area of ​​1261 μm 2 The number ratio of particles having a circle-converted diameter of the oxide of 2 μm or less is 90% or more.

[0021] 9. The sputtering target according to any one of 1 to 8 above, wherein the oxide contains an oxide of Si.

[0022] 10. A sputtering target according to claim 9, wherein the oxide further contains oxides of any one or more of the following elements, and the elements are selected from Al, B, Ba, Be, Ca, Ce, Cr, Dy, Er, Eu, Ga, Gd, Ho, Li, Mg, Mn, Nb, Nd, Pr, Sc, Sm, Sr, Ta, Tb, Ti, V, Y, Zn, and Zr.

[0023] 11. A sputtering target assembly comprising: the sputtering target according to any one of 1 to 10 above; and a backing plate joined to the sputtering target.

[0024] Effects of the Invention

[0025] According to the embodiments of the present invention, it is possible to provide a sputtering target and a sputtering target assembly in which the occurrence of cracks and breakages in the manufacturing process can be satisfactorily suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This figure shows an example of a binarized image and an original image in image analysis using ImageJ.

[0027] Figure 2 This is a screenshot of the setting conditions for binarization processing using ImageJ. DETAILED DESCRIPTION

[0028] Next, the specific embodiments of the present invention are described in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments, and it should be understood that, within the scope of the gist of the present invention, based on the common knowledge of those skilled in the art, appropriate changes, improvements, etc. in design can be made. The multiple constituent elements disclosed in each embodiment can form various inventions by appropriate combination. For example, several constituent elements can be deleted from all the constituent elements shown in each embodiment, and the constituent elements of different embodiments can also be appropriately combined.

[0029] <Sputtering target>

[0030] The shape of the sputtering target according to the embodiment of the present invention is not particularly limited, and may be a flat plate shape (including a disk shape and a rectangular plate shape), a cylindrical shape, or any other shape.

[0031] The sputtering target of the embodiment of the present invention comprises: (1) Fe; (2) Pt; (3) any one or more elements selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder. The remainder of (4) is an oxide, and may selectively contain impurities. The sputtering target of the embodiment of the present invention comprises a metal phase containing Fe and Pt as ferromagnetic materials and a phase containing oxides other than the metal phase, and can provide a function as a magnetic thin film.

[0032] The atomic ratio of Fe to Pt in the sputtering target according to the embodiment of the present invention is 34 to 55 at%. That is, the atomic ratio of Fe to Pt in the sputtering target is 34 to 55 at%. 100－X Pt X Where X satisfies 34≤X≤55. When Fe and Pt in the sputtering target satisfy such an atomic ratio, the function of the magnetic thin film is improved. The atomic ratio of Fe to Pt is preferably 40≤X≤53, and more preferably 44≤X≤51.

[0033] The total concentration of Fe and Pt in the sputtering target of the embodiment of the present invention is 50 mol% or more. When the total concentration of Fe and Pt in the sputtering target is 50 mol% or more, the magnetic properties are improved. The upper limit of the total concentration of Fe and Pt is not particularly limited, but is preferably 80 mol% or less from the viewpoint of ensuring the grain boundary material. In addition, the total concentration of Fe and Pt is more preferably 50 to 75 mol%, and further preferably 50 to 70 mol%.

[0034] The sputtering target of the embodiment of the present invention contains at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn, which is 0.5 to 15 mol% in total. These elements are components of the metal phase together with Fe and Pt, and by containing 0.5 to 15 mol% of these elements, the magnetic properties of the sputtering target with Fe and Pt as basic components are further improved. The content of the elements is more preferably 2 to 13 mol%, and more preferably 4 to 11 mol%.

[0035] The remainder of the sputtering target of the embodiment of the present invention is an oxide, which may selectively contain impurities. 2 When the oxide contains SiO 2 In addition, in order to further improve the magnetic properties, it may also contain oxides of any one or more of the following elements, wherein the elements are selected from Al, B, Ba, Be, Ca, Ce, Cr, Dy, Er, Eu, Ga, Gd, Ho, Li, Mg, Mn, Nb, Nd, Pr, Sc, Sm, Sr, Ta, Tb, Ti, V, Y, Zn, and Zr.

[0036] The volume fraction of the oxide of the sputtering target of the embodiment of the present invention is 40 vol.% or more. When the volume fraction of the oxide of the sputtering target is 40 vol.% or more, the magnetic properties are further improved. The upper limit of the volume fraction of the oxide of the sputtering target is not particularly limited, but from the viewpoint that the magnetic properties will deteriorate when there are too many oxides, it is preferably 60 vol.% or less. In addition, the volume fraction of the oxide of the sputtering target is more preferably 40 to 55 vol.%, and further preferably 40 to 50 vol.%. The volume fraction of the oxide can be calculated based on the composition of the target by (the content of each material: mol) × (the molecular weight of each material: g / mol) × (the inverse of the density of each material: cm 3 / g) to calculate and find the volume of each component contained in the target. Next, the volume fraction of the oxides can be calculated by dividing the total volume of only the oxides among the components by the total volume of all the components.

[0037] Impurities selectively included in the remainder of the sputtering target according to an embodiment of the present invention include: metal elements not included in the elements (1) to (3) above, and simple substances or compounds of elements such as C or N derived from gas components such as carbon dioxide and nitrogen in the atmosphere. The content of impurities selectively included in the remainder of the sputtering target according to an embodiment of the present invention may be less than 0.5 mol%, or less than 0.15 mol%. In addition, impurities may be analyzed by taking an analysis sample from the sputtering target and analyzing it using an infrared absorption method, an ICP emission spectrometer, or a GDMS (glow discharge mass spectrometer). The amount and shape of the analysis sample vary depending on the analysis method used, and the optimal amount and shape for each method may be selected.

[0038] In one aspect, the average particle area (Average size) of the oxide phase calculated using ImageJ (image processing software) using a scanning electron microscope (SEM) image with a field magnification of 3000 times is 4.0 μm. 2 When the average particle area of ​​the oxide phase of the sputtering target calculated by ImageJ is 4.0 μm 2 When the oxide structure is refined and the sputtering target has good strength. It is speculated that the oxide structure is refined and exists in a dispersed manner, so that the oxide phase and the phase containing Fe and Pt form a complex structure. Even if a tiny defect that may develop into a crack is generated, the boundary between the oxide phase and the phase containing Fe and Pt will become a barrier, and the defect will not develop, thereby suppressing the defect from becoming a crack or break. Therefore, in the manufacturing process of the sputtering target, the generation of cracks and breakages can be well suppressed in the hot pressing of the mixture obtained by crushing and mixing the powder of the raw materials, and the subsequent HIP processing for increasing the density of the sintered body. The average particle area of ​​the oxide phase of the sputtering target calculated using ImageJ is preferably 3.0μm 2 Below, more preferably 2.6 μm 2 Below, more preferably 2.5 μm 2 Below, more preferably 2.0 μm 2 Below, more preferably 1.7 μm 2 Below, more preferably 1.5 μm 2 Below, more preferably 1.0 μm 2 The lower limit of the average particle area of ​​the oxide phase of the sputtering target calculated using ImageJ does not need to be particularly limited, and may be, for example, 0.1 μm 2 Above, for example, 0.2 μm 2 Above, for example, 0.3 μm 2 Above, for example, 0.4 μm 2 Above, for example, 0.5 μm2 Above, for example, 0.6 μm 2 above.

[0039] The sputtering target of the embodiment of the present invention, on the other hand, uses a scanning electron microscope (SEM) image with a field of view magnification of 3000 times, and the average perimeter of the oxide phase calculated using ImageJ (image processing software) is less than 11.7 μm. When the average perimeter of the oxide phase of the sputtering target calculated using ImageJ is less than 11.7 μm, the structure of the oxide is refined, and the sputtering target has good strength. It is speculated that: the structure of the oxide is refined, and it exists in a dispersed manner, so that the oxide phase and the phase containing Fe and Pt become a complex structure, even if it is assumed that a tiny defect that may develop into a crack is generated, the boundary between the oxide phase and the phase containing Fe and Pt will also become a barrier, and the defect will not develop, and the defect is suppressed from becoming a crack or a rupture. Therefore, in the manufacturing process of the sputtering target, in the hot pressing of the mixture obtained by crushing and mixing the powder of the raw material, and in the subsequent HIP processing for increasing the density of the sintered body, etc., cracks and ruptures can be well suppressed. The average perimeter of the oxide phase of the sputtering target calculated using ImageJ is preferably 11.5 μm or less, more preferably 11.25 μm or less, more preferably 11.0 μm or less, more preferably 10.75 μm or less, more preferably 10.5 μm or less, more preferably 10.25 μm or less, more preferably 10.0 μm or less. The lower limit of the average perimeter of the oxide phase of the sputtering target calculated using ImageJ does not need to be particularly limited, for example, it may be 4.05 μm or more, for example, it may be 4.3 μm or more, for example, it may be 4.55 μm or more, for example, it may be 4.8 μm or more, for example, it may be 5.05 μm or more, for example, it may be 5.3 μm or more.

[0040] The method for measuring the average particle area (Average size) of the oxide phase and the average perimeter length of the oxide phase of the sputtering target according to the embodiment of the present invention will be described in detail.

[0041] First, the sputtering target is cut and its cross section is mirror-polished to prepare a SEM observation sample. Next, the SEM observation sample is observed using, for example, SEM (S-3700N, manufactured by Hitachi High Technologies). The setting during observation is as follows.

[0042] Image taken: secondary electron image, field of view magnification: 3000 times, acceleration voltage: 10~15kV.

[0043] The average particle area of ​​the oxide phase and the average perimeter of the oxide phase can be evaluated by binarizing the secondary electron image obtained in the above-mentioned imaging according to the following procedures (1) to (7) using ImageJ as image analysis software.

[0044] (1) Select File→Open in the ImageJ toolbar to load a 3000x magnification SEM image.

[0045] (2) Select 8-bit from Image → Type. Draw a straight line according to the scale and select Analyze → Set scale to set the scale.

[0046] (3) Select the area other than the scale bar of the image and select Image → Crop to extract the scale bar area.

[0047] (4) Select Process→Filters→Gaussian Blur, enter 2 for Sigma, and click OK.

[0048] (5) Select Process→Binary→Make Binary. The image is now binarized.

[0049] (6) Select Analyze → Set measurement and check Area.

[0050] (7) Select Analyze → Analyze Particle, set the analysis conditions to Size: 0-infinity, Circularity: 0.00-1.00, Show: nothing, check Summarize, and select OK. The results are displayed, and the Average Size and the average circumference of the oxide phase are read here.

[0051] As described above, the SEM image taken in is binarized using ImageJ, and the black particle portion is converted to black on the SEM image, and the black particles are taken as particles of the oxide phase, and the average particle area thereof is calculated. In addition, by binarization, the portion classified as black and darker than the surrounding color is converted to black, and the black portion is taken as the oxide phase, and the average perimeter thereof is calculated. It should be noted that the threshold of the binarization is automatically set according to the color histogram in the image. Figure 1 An example of the image after the binarization process and the original image is shown in FIG.

[0052] In yet another aspect, for the sputtering target according to an embodiment of the present invention, using a scanning electron microscope (SEM) image with a magnification of 3000 times, the oxide phase is calculated using ImageJ (image processing software), and the number average diameter of the equivalent circle diameters calculated by assuming the shape of the oxides in the oxide phase to be circular is 1.3 μm or less. When the number average diameter of the equivalent circle diameters calculated by assuming the shape of the oxides in the oxide phase of the sputtering target to be circular using ImageJ is 1.3 μm or less, the structure of the oxides is refined, and the sputtering target has good strength. It is speculated that: the structure of the oxides is refined and exists dispersedly, whereby the oxide phase and the phase containing Fe and Pt form a complex structure. Even if a minute defect that may develop into a crack occurs, the boundary between the oxide phase and the phase containing Fe and Pt will become a barrier, and the defect will not develop, suppressing the defect from becoming a crack or fracture. Therefore, in the manufacturing process of the sputtering target, in hot pressing of the mixture obtained by pulverizing and mixing raw material powders, and HIP processing and the like for improving the density of the sintered body thereafter, generation of cracks and fractures can be well suppressed. The number average diameter of the equivalent circle diameters calculated by assuming the shape of the oxides in the oxide phase of the sputtering target to be circular using ImageJ is preferably 1.25 μm or less, more preferably 1.20 μm or less, more preferably 1.15 μm or less, more preferably 1.10 μm or less, more preferably 1.05 μm or less, more preferably 1.00 μm or less, and more preferably 0.95 μm or less. The lower limit of the number average diameter of the equivalent circle diameters calculated by assuming the shape of the oxides in the oxide phase of the sputtering target to be circular using ImageJ is not particularly limited. For example, it can be 0.55 μm or more, for example, it can be 0.60 μm or more, for example, it can be 0.65 μm or more, for example, it can be 0.70 μm or more, for example, it can be 0.75 μm or more, for example, it can be 0.80 μm or more.

[0053] In yet another aspect, for the sputtering target according to an embodiment of the present invention, in the measurement area of a scanning electron microscope (SEM) photograph taken at a magnification of 3000 times, for every 1261 μm 2 the number of particles with a circle-converted diameter of 1 μm or less of the oxides is 100 or more. When for every 1261 μm of the measurement area 2When the number of particles of the oxide with a circular converted diameter of less than 1 μm is more than 100, the structure of the oxide is refined and the sputtering target has good strength. It is speculated that the structure of the oxide is refined and exists in a dispersed manner, so that the oxide phase and the phase containing Fe and Pt form a complex structure. Even if a tiny defect that may develop into a crack is generated, the boundary between the oxide phase and the phase containing Fe and Pt will become a barrier, and the defect will not develop, thereby suppressing the defect from becoming a crack or break. Therefore, in the manufacturing process of the sputtering target, the generation of cracks and breakage can be well suppressed in the hot pressing of the mixture obtained by crushing and mixing the powder of the raw materials, and the subsequent HIP processing for increasing the density of the sintered body. The measurement area is 1261 μm 2 The number of particles having a circle-converted diameter of the oxide of 1 μm or less is preferably 120 or more, more preferably 140 or more, more preferably 160 or more, more preferably 180 or more, more preferably 200 or more, and more preferably 220 or more. 2 The upper limit of the number of particles having a circle-converted oxide diameter of less than 1 μm does not need to be particularly limited, and may be, for example, 600 or less, 580 or less, 560 or less, 540 or less, 520 or less, or 500 or less.

[0054] In another aspect of the sputtering target according to the embodiment of the present invention, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number of particles having a circle-converted diameter of 2 μm or less of the oxide is 120 or more. 2 When the number of particles of the oxide with a circular converted diameter of less than 2 μm is 120 or more, the structure of the oxide is refined and the sputtering target has good strength. It is speculated that the structure of the oxide is refined and exists in a dispersed manner, so that the oxide phase and the phase containing Fe and Pt form a complex structure. Even if a tiny defect that may develop into a crack is generated, the boundary between the oxide phase and the phase containing Fe and Pt will become a barrier, and the defect will not develop, thereby suppressing the defect from becoming a crack or break. Therefore, in the manufacturing process of the sputtering target, the generation of cracks and breakage can be well suppressed in the hot pressing of the mixture obtained by crushing and mixing the powder of the raw materials, and the subsequent HIP processing for increasing the density of the sintered body. The measurement area is 1261 μm 2 The number of particles having a circle-converted diameter of the oxide of 2 μm or less is preferably 140 or more, more preferably 160 or more, more preferably 180 or more, more preferably 200 or more, more preferably 220 or more, and more preferably 240 or more.2 The upper limit of the number of particles having a circle-converted oxide diameter of 2 μm or less does not need to be particularly limited, and may be, for example, 640 or less, 620 or less, 600 or less, 580 or less, or 560 or less.

[0055] A method for measuring the number average diameter of the equivalent circle diameter calculated by assuming that the shape of the oxide of the oxide phase of the sputtering target according to the embodiment of the present invention is a circle, and a scanning electron microscope (SEM) photograph of the sputtering target according to the embodiment of the present invention taken at a field magnification of 3000 times, and a measurement area of ​​1261 μm 2 A method for measuring the number of particles having a circle-converted oxide diameter of 1 μm or less and 2 μm or less is described in detail.

[0056] First, the sputtering target is cut and its cross section is mirror-polished to prepare a SEM observation sample. Next, the SEM observation sample is observed using, for example, SEM (S-3700N, manufactured by Hitachi High Technologies). The setting during observation is as follows.

[0057] Image taken: secondary electron image, field of view magnification: 3000 times, acceleration voltage: 10~15kV.

[0058] In the secondary electron image, the metal matrix phase appears as a brighter portion than the surrounding area, and the oxide appears as a darker portion than the surrounding area.

[0059] Next, the image processing software (ImageJ made by National Institutes of Health) is used to binarize the photographed SEM image by the pattern method, and the Analyze Particles function of the image processing software is used to measure the area of ​​each oxide. For the area S of each oxide of the oxide phase thus obtained, the diameter D of each oxide is calculated by the following formula (1). The diameter D is divided by the number of oxides, thereby calculating the number average diameter of the equivalent circle diameter calculated by assuming the shape of the oxide of the oxide phase to be a circle. In addition, the diameter D is used as the circle conversion diameter of the oxide, and the number of particles with the circle conversion diameter of less than 1 μm and less than 2 μm is measured.

[0060]

[0061] The binarization using ImageJ is performed in the same manner as the method for measuring the average particle area (Average size) of the oxide phase and the average perimeter of the oxide phase described above, in the order shown in (1) to (7).

[0062] Thus, the results are shown, and here the area S of each oxide in the oxide phase is measured.

[0063] As described above, by the binarization process, the portion classified as black and darker than the surrounding area is converted to black, and the black portion is regarded as oxide.

[0064] It should be noted that the threshold of the binarization process is automatically set according to the color histogram in the image. Figure 1 An example of the image after the binarization process and the original image is shown in FIG.

[0065] In another aspect of the sputtering target according to the embodiment of the present invention, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number ratio of particles with a circle-converted diameter of the oxide of 1 μm or less is 60% or more. 2 When the number ratio of the particles with a circular converted diameter of the oxide of less than 1 μm is more than 60%, the structure of the oxide is refined and the sputtering target has good strength. It is speculated that the structure of the oxide is refined and exists in a dispersed manner, so that the oxide phase and the phase containing Fe and Pt form a complex structure. Even if a tiny defect that may develop into a crack is generated, the boundary between the oxide phase and the phase containing Fe and Pt will become a barrier, and the defect will not develop, thereby suppressing the defect from becoming a crack or break. Therefore, in the manufacturing process of the sputtering target, the generation of cracks and breakage can be well suppressed in the hot pressing of the mixture obtained by crushing and mixing the powder of the raw materials, and the subsequent HIP processing for increasing the density of the sintered body. The measurement area is 1261 μm 2 The number ratio of particles having a circle-converted diameter of the oxide of 1 μm or less is preferably 61.5% or more, more preferably 63% or more, more preferably 65% ​​or more, more preferably 67% or more, more preferably 68% or more, and more preferably 69% or more. 2 The upper limit of the number ratio of particles with a circle-converted diameter of the oxide of less than 1 μm does not need to be particularly limited, and may be, for example, less than 89.8%, less than 87.5%, less than 86%, less than 85%, less than 84%, or less than 83.4%.

[0066] In another aspect of the sputtering target according to the embodiment of the present invention, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number ratio of particles with a circle-converted diameter of the oxide of 2 μm or less is 90% or more. 2When the number ratio of particles with a circular converted diameter of the oxide of less than 2 μm is 90% or more, the structure of the oxide is refined and the sputtering target has good strength. It is speculated that the structure of the oxide is refined and exists in a dispersed manner, so that the oxide phase and the phase containing Fe and Pt form a complex structure. Even if a tiny defect that may develop into a crack is generated, the boundary between the oxide phase and the phase containing Fe and Pt will become a barrier, and the defect will not develop, thereby suppressing the defect from becoming a crack or break. Therefore, in the manufacturing process of the sputtering target, the generation of cracks and breakage can be well suppressed in the hot pressing of the mixture obtained by crushing and mixing the powder of the raw materials, and the subsequent HIP processing for increasing the density of the sintered body. The measurement area is 1261 μm 2 The number ratio of particles having a circle-converted diameter of the oxide of 2 μm or less is preferably 90.5% or more, more preferably 91% or more, more preferably 91.5% or more, more preferably 92% or more, more preferably 92.5% or more, and more preferably 93% or more. 2 The upper limit of the number ratio of particles having a circle-converted oxide diameter of less than 2 μm does not need to be particularly limited, and may be, for example, less than 98%, less than 97%, less than 96%, less than 95%, or less than 94%.

[0067] The scanning electron microscope (SEM) photograph of the sputtering target according to the embodiment of the present invention taken at a field magnification of 3000 times was used for every 1261 μm 2 The method for measuring the number ratio of particles having circle-converted oxide diameters of 1 μm or less and 2 μm or less is described in detail.

[0068] First, the measurement area of ​​the SEM photograph above is 1261 μm 2 The number of particles with a circle-converted diameter of 1 μm or less and 2 μm or less of the oxide is calculated in the same manner as the method for measuring the number of particles with a circle-converted diameter of 1 μm or less and 2 μm or less. Next, the number of particles with a circle-converted diameter of 1 μm or less and 2 μm or less of the oxide is calculated for each 1261 μm area of ​​the SEM photograph. 2 Evaluation is performed by measuring the ratio (%) of the number of particles having the circle-converted diameter of 1 μm or less and 2 μm or less to the number of all particles.

[0069] In another aspect, the sputtering target of the embodiment of the present invention has a bending strength of 300MPa or more. When the bending strength is 300MPa or more, cracks and fractures can be well suppressed in the manufacturing process. The bending strength is obtained by preparing 7 test pieces as described later, measuring the three-point bending strength, and calculating the average value thereof. Here, the three-point bending strength represents the maximum bending stress when the sample is broken by applying a load to the sample by a prescribed method. The sample breaks because the crack develops from one surface of the sample to another surface. That is, it means that when the maximum bending stress is high, the sample will not break before the high maximum bending stress. Therefore, it can be considered that when the maximum bending stress is high, cracks are not easy to develop from one surface to another surface. That is, it can be considered that by improving the bending strength, a target that is not easy to develop cracks and fractures can be made, and even if stress such as bending is applied in the manufacturing process, cracks and fractures are not easy to develop, so the generation of cracks and fractures can be well suppressed. The bending strength of the sputtering target according to the embodiment of the present invention is preferably 350 MPa or more, more preferably 400 MPa or more, further preferably 450 MPa or more, further preferably 500 MPa or more.

[0070] The bending strength of the sputtering target according to the embodiment of the present invention can be measured as follows.

[0071] First, the sputtering target was cut to prepare 7 test pieces. As a specific example of the cutting method, the sputtering target was processed to a thickness of 3 mm by lathe processing, and then cut into a size of 4 mm × 35 mm by discharge wire processing. Since the surface was oxidized, the surface was polished with #120 abrasive paper to remove the oxide film and prepare the sample.

[0072] Next, the three-point bending strength of the test piece was measured under the following measurement conditions, and the average value thereof was defined as the bending strength of the sputtering target.

[0073] <Measurement conditions>

[0074] A table material testing machine (STB-1225S) manufactured by A&D Corporation can be used as a measuring device. The bending strength of the sputtering target according to the embodiment of the present invention can be measured with reference to JIS R 1601:2008 "Test method for bending strength of refined ceramics". Table 1 shows the measurement conditions of the bending strength of the sputtering target according to the embodiment of the present invention and the measurement conditions of the bending strength described in JIS R 1601:2008. As shown in Table 1, the measurement conditions of the bending strength of the sputtering target according to the embodiment of the present invention are different from the measurement conditions of the bending strength described in JIS R 1601:2008 only in terms of "radius of curvature of the support", "length of the test piece", "parallelism", "edge of the test piece", "roughness Ra of the test piece", and "number of test pieces".

[0075] [Table 1]

[0076] JIS R 1601 Recording Conditions Measurement conditions of this embodiment Way Three-point bending method Three-point bending method Fixture shape Fixed three-point bending test fixture Fixed three-point bending test fixture Test piece shape Standard test piece I Standard test piece I Distance between pivot points (mm) 30±0.1 30 Curvature radius of support mm 2～3 5 Width of test piece mm 4.0±0.1 4.0±0.1 Test piece thickness mm 3.0±0.1 3.0±0.1 Test piece length mm 36-45 35±0.1 Parallelism mm ＜0.02 ＜0.04 The edge of the test piece Rounding or chamfering with r or c of 0.1-0.3mm Not implemented (no rounding / chamfering) Roughness of test piece Ra um ＜0.20 ＜0.4 Number of test pieces ＞10 7 Test crosshead speed mm / min 0.5 0.5

[0077] The sputtering target according to the embodiment of the present invention may be the following sputtering target.

[0078] A sputtering target comprising: (1) Fe; (2) Pt; (3) one or more elements selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, wherein the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the content of the elements of (3) is 0.5 to 15 mol% in total, and the remainder of (4) is oxide, optionally selectively containing impurities, the volume fraction of the oxide is 40 vol.% or more, and satisfies one or two or three or four or five or six or seven or eight or less items A to H.

[0079] A: The average particle size of the oxide phase calculated by ImageJ using a SEM image with a field magnification of 3000 times is 4.0 μm. 2 the following.

[0080] B: The average perimeter of the oxide phase calculated by ImageJ using a SEM image with a field magnification of 3000 times was 11.7 μm or less.

[0081] C: Flexural strength is 300 MPa or more.

[0082] D: The oxide phase was calculated using ImageJ using a SEM image with a field magnification of 3000 times, and the number average diameter of the equivalent circle diameter calculated by assuming that the shape of the oxide of the oxide phase was a circle was 1.3 μm or less.

[0083] E: Scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times, measuring area per 1261 μm 2 The number of particles having a circle-converted oxide diameter of 1 μm or less is 100 or more.

[0084] F: Scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times, per 1261 μm of measurement area 2 The number of particles having a circle-converted oxide diameter of 2 μm or less is 120 or more.

[0085] G: Scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times, measuring area per 1261 μm2 The number ratio of particles having a circle-converted diameter of the oxide of 1 μm or less is 60% or more.

[0086] H: Scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times, per 1261 μm of measurement area 2 The number ratio of particles having a circle-converted diameter of the oxide of 2 μm or less is 90% or more.

[0087] <Sputtering target assembly>

[0088] The sputtering target of the embodiment of the present invention can also be joined to a backing plate as needed to form a sputtering target assembly. The sputtering target assembly can be attached to a sputtering device for use. Indium and indium tin can be used as brazing materials. It should be noted that the sputtering target of the embodiment of the present invention can also be attached to a sputtering device as it is without using a backing plate. The material of the backing plate is not particularly limited, and examples thereof include: Cu, Ti, Mo, and alloys containing at least one of them (for example, Cu-Ni-Si alloys (for example, C18000, etc.), CuZn alloys, CuCr alloys), etc. The material of the backing plate preferably has high thermal conductivity, and from this point of view, Cu is preferred.

[0089] <Method for producing sputtering target>

[0090] Hereinafter, a method for producing a sputtering target according to an embodiment of the present invention will be described in detail.

[0091] The sputtering target of the embodiment of the present invention can be produced by a powder sintering method. First, powders of each metal element are prepared. In addition, alloy powders of these metals (for example, Fe-Pt powder) can also be used instead of the powders of each metal element. The purity of these raw materials can generally be 2N (99 mass %) or more, preferably 3N (99.9 mass %) or more, and more preferably 4N (99.99 mass %) or more. If the purity is lower than 2N, a large amount of impurities will be contained in the sintered body, so there may be a problem that the desired physical properties cannot be obtained (for example, particles are generated along with arcing). These raw materials can be appropriately prepared according to the composition and purity of the desired sintered body.

[0092] Then, these metal powders are weighed in a manner to form a desired composition, and a mixing device is used for both crushing and mixing. In addition, non-magnetic particles can also be mixed with metal powders at this stage. As a mixing device, a ball mill, a mortar, etc. can be used, and it is ideal to use a powerful mixing method such as a ball mill. In addition, if the problem of oxidation during mixing is considered, it is preferably mixed in an inert gas atmosphere or in a vacuum. In addition, the mixing time is set to 0.1 to 48 hours.

[0093] By extending the mixing time of the raw materials, the average particle area of ​​the oxide phase can be reduced. On the other hand, by shortening the mixing time of the raw materials, the average particle area of ​​the oxide phase can be increased. From such a point of view, the average particle area of ​​the oxide phase is controlled by adjusting the mixing time of the raw materials.

[0094] In addition, by extending the mixing time of the raw materials, the average perimeter of the oxide phase can be reduced. On the other hand, by shortening the mixing time of the raw materials, the average perimeter of the oxide phase can be increased. From such a viewpoint, the average perimeter of the oxide phase is controlled by adjusting the mixing time of the raw materials.

[0095] In addition, by extending the mixing time of the raw materials, the oxides in the oxide phase can be reduced, thereby increasing the bending strength of the sputtering target. It is known that oxides have lower toughness than metals. In a sintered body having a structure in which oxides are dispersed in a parent metal, the starting point of the crack is mostly the oxide phase with low toughness. By making the oxide particles finer and finely dispersing them, the proportion of coarser oxides in the sintered body is reduced, and the generation of cracks is suppressed, thereby expecting an increase in bending strength. On the other hand, by shortening the mixing time of the raw materials, the oxides in the oxide phase can be increased. From this point of view, the bending strength of the sputtering target is controlled by adjusting the mixing time of the raw materials.

[0096] In addition, by extending the mixing time of the raw materials, the number average diameter of the equivalent circle diameter calculated by assuming the shape of the oxide of the oxide phase as a circle can be reduced. On the other hand, by shortening the mixing time of the raw materials, the number average diameter of the equivalent circle diameter calculated by assuming the shape of the oxide of the oxide phase as a circle can be increased. From such a viewpoint, the number average diameter of the equivalent circle diameter calculated by assuming the shape of the oxide of the oxide phase as a circle is controlled by adjusting the mixing time of the raw materials.

[0097] In addition, by extending the mixing time of the raw materials, the measurement area of ​​the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times can be increased by 1261 μm 2 On the other hand, by shortening the mixing time of the raw materials, the measurement area of ​​the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times can be reduced by 1261 μm 2 The number or ratio of particles having a circle-converted diameter of 1 μm or less or 2 μm or less of the oxide is determined. From this point of view, the mixing time of the raw materials is adjusted to control the number of particles per 1261 μm of the measurement area of ​​the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times. 2 The number or number ratio of particles having a circle-converted diameter of the oxide of 1 μm or less or 2 μm or less.

[0098] The mixed powder thus obtained is molded and sintered using a hot press apparatus to produce a sintered body. Molding and sintering are not limited to hot pressing, and plasma discharge sintering or hot isostatic pressing sintering may also be used. The sintering conditions are set at 650 to 1400° C. for 0.5 to 12 hours.

[0099] If the sintering temperature is increased and / or the sintering time is extended, the average particle area of ​​the oxide phase can be increased. On the other hand, if the sintering temperature is reduced and / or the sintering time is shortened, the average particle area of ​​the oxide phase can be reduced. From such a viewpoint, the average particle area of ​​the oxide phase can be controlled by adjusting the sintering temperature and the sintering time.

[0100] In addition, if the sintering temperature is increased and / or the sintering time is extended, the average perimeter of the oxide phase can be increased. On the other hand, if the sintering temperature is reduced and / or the sintering time is shortened, the average perimeter of the oxide phase can be reduced. From such a viewpoint, the average perimeter of the oxide phase is controlled by adjusting the sintering temperature and the sintering time.

[0101] In addition, if the sintering temperature is increased and / or the sintering time is extended, the oxide of the oxide phase can be increased. On the other hand, if the sintering temperature is reduced and / or the sintering time is shortened, the oxide of the oxide phase can be reduced. From such a viewpoint, the size of the oxide of the oxide phase is controlled by adjusting the sintering temperature and the sintering time, thereby controlling the bending strength of the sputtering target.

[0102] In addition, if the sintering temperature is increased and / or the sintering time is extended, the number average diameter of the equivalent circular diameter calculated by assuming the shape of the oxide of the oxide phase as a circle can be increased. On the other hand, if the sintering temperature is reduced and / or the sintering time is shortened, the number average diameter of the equivalent circular diameter calculated by assuming the shape of the oxide of the oxide phase as a circle can be reduced. From such a viewpoint, the number average diameter of the equivalent circular diameter calculated by assuming the shape of the oxide of the oxide phase as a circle can be controlled by adjusting the sintering temperature and the sintering time.

[0103] In addition, if the sintering temperature is increased and / or the sintering time is prolonged, the measured area of ​​the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times can be increased by 1261 μm 2 On the other hand, if the sintering temperature is lowered and / or the sintering time is shortened, the number of particles or the ratio of particles having a circle-converted diameter of the oxide of 1 μm or less or 2 μm or less can be reduced by reducing the measurement area of ​​the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times per 1261 μm 2The number or ratio of particles having a circle-converted diameter of 1 μm or less or 2 μm or less of the oxide is determined. From this point of view, the sintering temperature and sintering time are adjusted to control the number of particles per 1261 μm of the measurement area of ​​the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times. 2 The number or number ratio of particles having a circle-converted diameter of the oxide of 1 μm or less or 2 μm or less.

[0104] Then, the sintered body taken out from the hot pressing device is subjected to HIP (Hot Isostatic Pressing). HIP processing is an effective method for increasing the density of the sintered body. The holding temperature during HIP processing is set to 650-1100°C, the holding time is set to 0.5-12 hours, and the pressure is set to 100 MPa or more. Then, the sintered body obtained in this way is processed into the desired shape using a lathe, thereby making a sputtering target.

[0105] <Film formation method using sputtering target>

[0106] The sputtering target of the embodiment of the present invention can mainly form a thin film constituting a magnetic recording medium. Specifically, a sputtering device is used to sputter the surface of the sputtering target by accelerated argon ions, so that particles (sputtered particles) are released from the sputtering target, and the sputtered particles are deposited on the surface of a substrate pre-configured at an opposing position, thereby forming a thin film on the surface of the substrate. The sputtering conditions can be appropriately set according to the desired film thickness, composition, etc.

[0107] Example

[0108] Examples of the present invention are shown below. However, these examples are provided for better understanding of the present invention and its advantages and are not intended to limit the present invention.

[0109] <Example 1>

[0110] The sputtering target of Example 1 was manufactured by the following manufacturing method.

[0111] As raw material powders, Fe powder, Pt powder, Ag powder, SiO 2 Powder, with a composition of (30~45)Fe-(30~45)Pt-(5~15)Ag-(5~25)SiO 2 The raw material powder was weighed in such a way that the total composition was 100 mol%. 2 Amorphous powder was used as the powder. Next, the weighed Fe powder, Pt powder, Ag powder, SiO 2 The powder and zirconium oxide balls were placed in a 5 L ball mill and mixed for 4 hours.

[0112] Next, the mixed powder taken out from the ball mill tank is filled into a carbon mold and hot pressed. The conditions for hot pressing are set as vacuum atmosphere, heating rate of 300°C / hour, holding temperature (sintering temperature) of 900°C, holding time (sintering time) of 2 hours, and pressurization at 30MPa from the start of heating to the end of holding. After the holding is completed, the state is maintained in the chamber for natural cooling. Then, the sintered body taken out from the hot pressing mold is subjected to HIP processing. The conditions for HIP processing are set as heating rate of 300°C / hour, holding temperature of 850°C, and holding time of 2 hours. The gas pressure of Ar gas is slowly increased from the start of heating, and pressurization is applied at 150MPa during holding. After the holding is completed, the state is maintained in the furnace for natural cooling. Thus, the sputtering target of Example 1 is produced.

[0113] <Examples 2 to 8, Comparative Example 1>

[0114] Sputtering targets of Examples 2 to 8 and Comparative Example 1 were produced in the same manner as in Example 1. The mixing time of the raw material powders, the hot pressing temperature, and the HIP holding temperature were carried out under the conditions shown in Table 2, respectively.

[0115] Average particle area of ​​oxide phase, average perimeter of oxide phase

[0116] First, the sputtering target was cut and the cross section was mirror-polished to prepare a SEM observation sample. Next, the SEM observation sample was observed using a SEM (S-3700N, manufactured by Hitachi High Technologies). The settings during observation were as follows.

[0117] Image taken: secondary electron image, field of view magnification: 3000 times, acceleration voltage: 10~15kV.

[0118] The average particle area of ​​the oxide phase and the average perimeter of the oxide phase were evaluated by binarizing the secondary electron image obtained in the above-mentioned imaging according to the following procedures (1) to (7) using ImageJ as image analysis software.

[0119] (1) Select File→Open in the ImageJ toolbar to load a 3000x magnification SEM image.

[0120] (2) Select 8-bit from Image → Type. Draw a straight line according to the scale and select Analyze → Set scale to set the scale.

[0121] (3) Select the area other than the scale bar of the image and select Image → Crop to extract the scale bar area.

[0122] (4) Select Process→Filters→Gaussian Blur, enter 2 for Sigma, and click OK.

[0123] (5) Select Process→Binary→Make Binary. The image is now binarized.

[0124] In addition, a screenshot of the setting conditions is provided in Figure 2 .

[0125] (6) Select Analyze → Set measurement and check Area.

[0126] (7) Select Analyze → Analyze Particle, set the analysis conditions to Size: 0-infinity, Circularity: 0.00-1.00, Show: nothing, check Summarize, and select OK. The results are displayed, and the value of Average Size is read here.

[0127] As described above, after the SEM image is taken in by ImageJ, a binarization process is performed, and the black particle part is converted into black on the SEM image, and the black particles are used as particles of the oxide phase, and the average particle area thereof is calculated. In addition, by the binarization process, the part that is classified as black and darker than the surrounding color is converted into black, and the black part is used as the oxide phase, and the average perimeter thereof is calculated. It should be noted that the threshold value of the binarization process is automatically set according to the color histogram in the image.

[0128] The number average diameter of the equivalent circle diameter calculated by assuming that the shape of the oxide phase is a circle and the measured area of ​​1261 μm of the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times 2 The number of particles with a circle-converted diameter of 1 μm or less or 2 μm or less of the oxide

[0129] First, the sputtering target was cut and the cross section was mirror-polished to prepare a SEM observation sample. Next, the SEM observation sample was observed using a SEM (S-3700N, manufactured by Hitachi High Technologies). The settings during observation were as follows.

[0130] Image taken: secondary electron image, field of view magnification: 3000 times, acceleration voltage: 10~15kV.

[0131] In the secondary electron image, the metal matrix phase appears as a brighter portion than the surrounding area, and the oxide appears as a darker portion than the surrounding area.

[0132] Next, using image processing software (ImageJ made by the National Institutes of Health), the captured SEM images were binarized by the thresholding method, and the area of each oxide was measured using the Analyze Particles function of the image processing software. For the area S of each oxide in the oxide phase obtained thereby, the diameter D of each oxide was calculated by the following formula (1). By dividing the diameter D by the number of oxides, the number-average diameter of the equivalent circle diameters calculated assuming the shape of the oxides in the oxide phase to be circular was calculated. In addition, the diameter D was used as the circle-converted diameter of the oxide, and the number of particles with a circle-converted diameter of 1 μm or less or 2 μm or less was measured.

[0133]

[0134] It should be noted that the binarization of the above ImageJ was performed in the order shown in the above (1) to (7).

[0135] Thus, the results were displayed, and the area S of each oxide in the oxide phase was measured here.

[0136] As described above, through the binarization process, the portion with a darker color than the surroundings that was divided into black was converted to black, and the black portion was regarded as an oxide.

[0137] It should be noted that the threshold value for the binarization process was automatically set according to the color histogram in the image.

[0138] · The number ratio of particles with a circle-converted diameter of 1 μm or less or 2 μm or less per 1261 μm of the measurement area of a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times 2 of the oxides

[0139] First, in the same manner as the method for measuring the number of particles with a circle-converted diameter of 1 μm or less or 2 μm or less per 1261 μm of the measurement area of the above SEM photograph, the number of particles with a circle-converted diameter of 1 μm or less or 2 μm or less was calculated separately. Next, the ratios (%) of the number of the above particles with a circle-converted diameter of 1 μm or less and 2 μm or less measured per 1261 μm of the measurement area of the SEM photograph to the total number of particles were calculated separately, and evaluation was performed thereby. 2 2 2 2

[0140] · Volume fraction of oxides

[0141] Regarding the evaluation of the volume fraction of oxides, by (content of each material: mol) × (molecular weight of each material: g / mol) × (reciprocal of the density of each material: cm3 Next, the volume ratio of the oxides is calculated by dividing the total volume of only the oxides among the components by the total volume of all the components.

[0142] Bending strength

[0143] The sputtering target samples were cut to prepare 7 test pieces. As the cutting method, the sputtering target was processed to a thickness of 3 mm by lathe processing, and then cut into a size of 4 mm × 35 mm by discharge wire processing. Next, since the surface was oxidized, the surface was polished with #120 abrasive paper to remove the oxide film and prepare the sample.

[0144] Next, the three-point bending strength was measured under the following measurement conditions, and the average value thereof was defined as the bending strength of the sputtering target. In addition, the bending strength test for Examples 3 to 8 was not performed.

[0145] <Measurement conditions>

[0146] A table material testing machine (STB-1225S) manufactured by A&D Co., Ltd. was used as a measuring device. The bending strength of the sputtering target of this test example was measured with reference to JIS R 1601:2008 "Bending Strength Test Method for Refined Ceramics", and was implemented by the "Measurement Conditions of the Present Embodiment" shown in the above Table 1. That is, as shown in the above Table 1, the measurement conditions of the bending strength of the sputtering target of this test example are different from the measurement conditions of the bending strength described in JIS R 1601:2008 only in terms of "curvature radius of support", "test piece length", "parallelism", "edge of test piece", "roughness Ra of test piece", and "number of test pieces".

[0147] ·rupture

[0148] The surface of each of the sputtering targets of the examples and comparative examples was visually checked to evaluate whether cracks occurred at least a little or not. The evaluation determined whether cracks and cracks were suppressed during the manufacturing process.

[0149] The evaluation results are shown in Tables 2 and 3.

[0150] [Table 2]

[0151]

[0152] [Table 3]

[0153]

[0154] <Investigation>

[0155] According to Tables 2 and 3, the sputtering targets of Examples 1 to 8 each have: (1) Fe; (2) Pt; (3) any one or more elements selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, the atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, the total concentration of (1) Fe and (2) Pt is 50 mol% or more, the content of the elements in (3) is 0.5 to 15 mol% in total, and the remainder of (4) is oxide, and the volume fraction of the oxide is 40 vol.% or more.

[0156] In addition, the average particle area (Average size) of the oxide phase calculated using ImageJ using the SEM image with a field magnification of 3000 times for each of the sputtering targets of Examples 1 to 8 was 4.0 μm. 2 Therefore, the bending strength is good, and the occurrence of cracks and breakages during the manufacturing process is suppressed.

[0157] Furthermore, the bending strength of each of the sputtering targets of Examples 1 and 2 was 300 MPa or more. Therefore, the occurrence of cracks and breakages in the production process was suppressed.

[0158] In addition, the average perimeter of the oxide phase calculated using ImageJ using a SEM image with a field magnification of 3000 times in each of the sputtering targets of Examples 1 to 8 was 11.7 μm or less. Therefore, the bending strength was good, and the occurrence of cracks and breakages during the manufacturing process was suppressed.

[0159] In addition, the oxide phase of each of the sputtering targets of Examples 1 to 8 was calculated using ImageJ using a SEM image with a field magnification of 3000 times, and the number average diameter of the equivalent circle diameter calculated by assuming the shape of the oxide of the oxide phase to be a circle was 1.3 μm or less. Therefore, the bending strength was good, and cracks and breakages were suppressed during the manufacturing process.

[0160] In addition, the scanning electron microscope (SEM) photographs of the sputtering targets of Examples 1 to 8 taken at a field magnification of 3000 times showed that the measured area was 1261 μm 2 The number of particles with a circle-converted diameter of 1 μm or less of the oxide is at least 100. In addition, the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number of particles having a circle-converted diameter of 2 μm or less of the oxide was 120 or more. In addition, the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times had a measured area of ​​1261 μm 2The number ratio of particles with a circle-converted diameter of 1 μm or less of the oxide is 60% or more. In addition, the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number ratio of particles having a circle-converted diameter of the oxide of 2 μm or less is 90% or more. Therefore, the bending strength is good, and the occurrence of cracks and breakages in the manufacturing process is suppressed.

[0161] In contrast, the average particle size of the oxide phase calculated by ImageJ using the SEM image with a field magnification of 3000 times in Comparative Example 1 was greater than 4.0 μm. 2 Therefore, the bending strength is poor, and cracks and breakages occur during the manufacturing process.

[0162] In addition, the average perimeter of the oxide phase calculated by ImageJ using a SEM image with a field magnification of 3000 times in Comparative Example 1 was greater than 11.7 μm. Therefore, the bending strength was poor, and cracks and breakage occurred during the manufacturing process.

[0163] Furthermore, the bending strength of Comparative Example 1 was less than 300 MPa, so cracks and breakages occurred during the manufacturing process.

[0164] In addition, the oxide phase of Comparative Example 1 was calculated using ImageJ using a SEM image with a field magnification of 3000 times, and the number average diameter of the equivalent circle diameter calculated by assuming the shape of the oxide of the oxide phase to be a circle was greater than 1.3 μm. Therefore, the bending strength was poor, and cracks and breakages occurred during the manufacturing process.

[0165] In addition, the scanning electron microscope (SEM) photograph of Comparative Example 1 taken at a field magnification of 3000 times showed that the measured area was 1261 μm 2 The number of particles with a circle-converted diameter of 1 μm or less of the oxide is less than 100, and the measured area of ​​the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 2 The number of particles with a circle-converted diameter of 2 μm or less of the oxide is less than 120, and the ... 2 The number of particles with a circle-converted diameter of 1 μm or less of the oxide is less than 60%, and the measured area of ​​the scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 2 The number ratio of particles having a circle-converted diameter of the oxide of 2 μm or less is less than 90%. Therefore, the bending strength is poor, and cracks and breakages occur during the manufacturing process.

[0166] According to one embodiment of the present invention, a sputtering target and a sputtering target assembly can be obtained, wherein the sputtering target can effectively suppress cracks and breakages in the manufacturing process, and thus may contribute to the advancement of thin film forming technology using sputtering for the manufacture of hard disk media, etc. Therefore, one embodiment of the present invention may contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Striving to build resilient infrastructure, promote inclusive and sustainable industrialization, and advance innovation."

Claims

1. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder. The atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, The total concentration of (1) Fe and (2) Pt is 50 mol% or more, The total content of the elements in (3) is 0.5 to 15 mol%. The remainder of (4) is oxides, which may selectively contain impurities, and the volume fraction of the oxides is 40 vol.% or more, In the sputtering target, the average particle area of ​​the oxide phase, i.e., the average size, was calculated by using ImageJ using a SEM image with a field magnification of 3000 times, and was 4.0 μm. 2 the following.

2. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder, The atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, The total concentration of (1) Fe and (2) Pt is 50 mol% or more, The total content of the elements in (3) is 0.5 to 15 mol%. The remainder of (4) is oxides, which may selectively contain impurities, and the volume fraction of the oxides is 40 vol.% or more, In the sputtering target, the average perimeter of the oxide phase calculated by using ImageJ using a SEM image with a field magnification of 3000 times was 11.7 μm or less.

3. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder. The atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, The total concentration of (1) Fe and (2) Pt is 50 mol% or more, The total content of the elements in (3) is 0.5 to 15 mol%. The remainder of (4) is oxides, which may selectively contain impurities, and the volume fraction of the oxides is 40 vol.% or more, The sputtering target has a bending strength of 300 MPa or more.

4. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder. The atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, The total concentration of (1) Fe and (2) Pt is 50 mol% or more, The total content of the elements in (3) is 0.5 to 15 mol%. The remainder of (4) is oxides, which may selectively contain impurities, and the volume fraction of the oxides is 40 vol.% or more, In the sputtering target, the oxide phase was calculated using ImageJ using a SEM image with a field magnification of 3000 times, and the number average diameter of the equivalent circle diameter calculated by assuming that the shape of the oxide in the oxide phase was a circle was 1.3 μm or less.

5. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder. The atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, The total concentration of (1) Fe and (2) Pt is 50 mol% or more, The total content of the elements in (3) is 0.5 to 15 mol%. The remainder of (4) is oxides, which may selectively contain impurities, and the volume fraction of the oxides is 40 vol.% or more, In the sputtering target, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number of particles having a circle-converted oxide diameter of 1 μm or less is 100 or more.

6. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder. The atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, The total concentration of (1) Fe and (2) Pt is 50 mol% or more, The total content of the elements in (3) is 0.5 to 15 mol%. The remainder of (4) is oxides, which may selectively contain impurities, and the volume fraction of the oxides is 40 vol.% or more, In the sputtering target, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number of particles having a circle-converted oxide diameter of 2 μm or less is 120 or more.

7. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder. The atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, The total concentration of (1) Fe and (2) Pt is 50 mol% or more, The total content of the elements in (3) is 0.5 to 15 mol%. The remainder of (4) is oxides, which may selectively contain impurities, and the volume fraction of the oxides is 40 vol.% or more, In the sputtering target, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number ratio of particles having a circle-converted diameter of the oxide of 1 μm or less is 60% or more.

8. A sputtering target comprising: (1) Fe; (2) Pt; (3) at least one element selected from Ag, Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Si, Sn, Ta, W, V, and Zn; and (4) the remainder. The atomic ratio of (1) Fe to (2) Pt is 34 to 55 at%, The total concentration of (1) Fe and (2) Pt is 50 mol% or more, The total content of the elements in (3) is 0.5 to 15 mol%. The remainder of (4) is oxides, which may selectively contain impurities, and the volume fraction of the oxides is 40 vol.% or more, In the sputtering target, a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times has a measurement area of ​​1261 μm 2 The number ratio of particles having a circle-converted diameter of the oxide of 2 μm or less is 90% or more.

9. The sputtering target according to any one of claims 1 to 8, wherein The oxide includes an oxide of Si.

10. The sputtering target according to claim 9, wherein The oxide also contains oxides of any one or more of the following elements, and the elements are selected from Al, B, Ba, Be, Ca, Ce, Cr, Dy, Er, Eu, Ga, Gd, Ho, Li, Mg, Mn, Nb, Nd, Pr, Sc, Sm, Sr, Ta, Tb, Ti, V, Y, Zn, and Zr.

11. A sputtering target assembly, comprising: The sputtering target according to any one of claims 1 to 8; and A backing plate is bonded to the sputtering target.

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