Sputtering target and sputtering target assembly

Abstract

This sputtering target has (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. The atomic ratio between (1) Fe and (2) Pt is 34-55 at%. The total concentration of (1) Fe and (2) Pt is 50 mol% or above, and total amount of the elements (3) is 0.5-15 mol%. The (4) remainder is an oxide, and may selectively include impurities. The volume ratio of the oxide is 40 vol% or more. The average particle area (average size) of the oxide phase calculated using ImageJ using an SEM image having a visual field magnification of 3000 is 4.0 μm2 or less.

Description

Sputtering targets and sputtering target assemblies

[0001] The present invention relates to a sputtering target and a sputtering target assembly, and primarily to a sputtering target for the production of films for HDDs.

[0002] The layers constituting hard disk drives (HDDs) that employ perpendicular magnetic recording systems are made of materials based on ferromagnetic metals such as Co, Fe, and Ni, and the recording layers are often made of composite materials composed of ferromagnetic alloys, such as Co—Cr, Co—Pt, Co—Cr—Pt, and Fe—Pt, which are primarily composed of Co or Fe, and non-magnetic inorganic materials. Thin films for magnetic recording media such as hard disk drives are often produced by sputtering targets containing the above-mentioned materials, due to their high productivity.

[0003] In general, sputtering targets are manufactured by first crushing and mixing raw material powders, and then hot-pressing the resulting mixture to obtain a sintered body. To increase the density of the sintered body, HIP (Hot Isostatic Pressing) processing may then be performed. The sintered body thus obtained is then machined on a lathe to produce a target of a desired shape (see Patent Documents 1 and 2).

[0004] Patent No. 6030271 Patent No. 6305881

[0005] As described above, a composite material composed of a ferromagnetic alloy such as an Fe—Pt alloy and a nonmagnetic inorganic material is useful as a recording layer for a HDD. However, when a sintered body having a structure in which oxides are dispersed in a base metal containing Fe and Pt is produced as a sputtering target for producing such a recording layer, the sintered body having this composition is relatively brittle, and there is a problem in that cracks and breakage occur during the production process.

[0006] Therefore, an object of an embodiment of the present invention is to provide a sputtering target and a sputtering target assembly that can effectively suppress the occurrence of cracks and breakage during the manufacturing process.

[0007] The above problems are solved by the present invention, which is specified as follows: 1. The present invention relates to a ferroelectric material having (1) Fe, (2) Pt, and (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, and the average particle area (Average size) is 4.0 μm 2A sputtering target that is:2. 1. 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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the total content of the (3) element is 0.5 to 15 mol %, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, and the average perimeter of the oxide phase calculated using ImageJ on an SEM image with a field magnification of 3000 times is 11.7 μm or less. 3. 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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance (4) is an oxide which may selectively contain impurities, the volume fraction of the oxide is 40 vol. % or more, and the bending strength is 300 MPa or more.4. A ceramic material 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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, 4. A sputtering target in which the number average diameter of the equivalent circle diameter calculated using ImageJ on an SEM image at a field magnification of 3000 times and assuming that the shape of the oxides in the oxide phase is circular is 1.3 μm or less. %と50mol%。 The composition of claim 1, wherein the composition of claim 1 is a crystalline silicon alloy, and the composition of claim 2 is a crystalline silicon alloy. The composition of claim 1 is a crystalline silicon alloy, and the composition of claim 2 is a crystalline silicon alloy. The composition of claim 2 is a crystalline silicon alloy, and the composition of claim 2 is a crystalline silicon alloy. The composition of claim 2 is a crystalline silicon alloy, and the composition of claim 2 is a crystalline silicon alloy. 25. A sputtering target having 100 or more oxide particles each having an equivalent circular diameter of 1 μm or less. (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 2 6. A sputtering target having 120 or more oxide particles each having an equivalent circular diameter of 2 μm or less. (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 27. A sputtering target in which the proportion of particles having an equivalent circular diameter of 1 μm or less per oxide is 60% or more. (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 2 8. A sputtering target in which the proportion of particles having an equivalent circular diameter of 2 μm or less per particle is 90% or more. 9. The sputtering target according to any one of 1 to 8 above, wherein the oxide contains an oxide of Si. 10. The sputtering target according to 9 above, wherein the oxide further contains one or more oxides of elements 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 1 to 10 above; and a backing plate bonded to the sputtering target.

[0008] According to the embodiments of the present invention, it is possible to provide a sputtering target and a sputtering target assembly that can effectively suppress the occurrence of cracks and breakage during the manufacturing process.

[0009] 1 shows an example of a binarized image and an original image in image analysis using ImageJ. 2 is a screenshot of the setting conditions for binarization processing using ImageJ.

[0010] Next, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that appropriate design changes, improvements, etc. may be made based on the common knowledge of those skilled in the art without departing from the spirit of the present invention. The multiple components disclosed in each embodiment can be appropriately combined to form various inventions. For example, some components may be omitted from all the components shown in each embodiment, or components from different embodiments may be appropriately combined.

[0011] <Sputtering Target> The shape of the sputtering target according to the embodiment of the present invention is not particularly limited, and may be a flat plate (including a disk or rectangular plate), a cylindrical shape, or any other shape.

[0012] A sputtering target according to an embodiment of the present invention comprises (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 balance. The balance in (4) is an oxide and may selectively contain impurities. The sputtering target according to an embodiment of the present invention comprises a metal phase containing ferromagnetic materials Fe and Pt, and a phase other than the metal phase containing an oxide, and can be provided with the function of a magnetic thin film.

[0013] In the sputtering target according to the embodiment of the present invention, the atomic ratio of Fe to Pt is 34 to 55 at %. That is, the atomic ratio of Fe to Pt in the sputtering target is as follows: 100-X Pt X In the sputtering target, X satisfies the atomic ratio of 34≦X≦55. When the Fe and Pt in the sputtering target satisfy this atomic ratio, the function as a magnetic thin film is improved. The atomic ratio of Fe and Pt is preferably 40≦X≦53, and more preferably 44≦X≦51.

[0014] The sputtering target according to an embodiment of the present invention has a total concentration of Fe and Pt of 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. There is no particular upper limit to the total concentration of Fe and Pt, but from the viewpoint of ensuring grain boundary material, it is preferably 80 mol% or less. Furthermore, the total concentration of Fe and Pt is more preferably 50 to 75 mol%, and even more preferably 50 to 70 mol%.

[0015] A sputtering target according to an embodiment of the present invention contains 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 in a total content of 0.5 to 15 mol%. These elements, along with Fe and Pt, are components of the metal phase, and by containing 0.5 to 15 mol%, the magnetic properties of a sputtering target based on Fe and Pt are further improved. The content of these elements is more preferably 2 to 13 mol%, and even more preferably 4 to 11 mol%.

[0016] The sputtering target according to an embodiment of the present invention may contain, as the remainder, an oxide and may selectively contain impurities. A particularly preferable magnetic thin film can be obtained by using SiO2 as the oxide. Furthermore, in addition to SiO2, the oxide may further contain one or more oxides of elements 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 to further improve magnetic properties.

[0017] In the sputtering target according to the embodiment of the present invention, the volume fraction of oxide is 40 vol.% or more. When the volume fraction of oxide in the sputtering target is 40 vol.% or more, the magnetic properties are further improved. There is no particular upper limit to the volume fraction of oxide in the sputtering target, but from the viewpoint that if the amount of oxide is too large, the magnetic properties deteriorate, it is preferably 60 vol.% or less. Furthermore, the volume fraction of oxide in the sputtering target is more preferably 40 to 55 vol.%, and even more preferably 40 to 50 vol.%. The volume fraction of oxide can be calculated from the composition of the target, and the volume of each component contained in the target is calculated by multiplying the volume of each component by (content of each material: mol) x (molecular weight of each material: g / mol) x (reciprocal of density of each material: cm 3 Next, the volume fraction of oxides can be calculated by dividing the total volume of only oxides among the components by the total volume of all components.

[0018] Impurities selectively contained in the remainder of the sputtering target according to the 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 from gas components such as carbon dioxide and nitrogen in the atmosphere. The content of impurities selectively contained in the remainder of the sputtering target according to the embodiment of the present invention may be 0.5 mol% or less, or may be 0.15 mol% or less. Furthermore, impurities can be analyzed by collecting an analytical sample from the sputtering target and using infrared absorption spectroscopy, an ICP optical emission spectrometer, GDMS (glow discharge mass spectrometry), or the like. The amount and shape of the analytical sample vary depending on the analytical method used, and the optimal amount and shape for each method can be selected.

[0019] In one aspect, the sputtering target according to the embodiment of the present invention has an oxide phase average particle area (average size) of 4.0 μm calculated using a scanning electron microscope (SEM) image with a field magnification of 3000 times and ImageJ (image processing software). 2 The average grain area of ​​the oxide phase of the sputtering target calculated using ImageJ is 4.0 μm or less.2 If the oxide structure is below this range, the oxide structure is finer and the sputtering target has good strength. The oxide structure is finer and dispersed, resulting in a complex structure of the oxide phase and the phase containing Fe and Pt. Even if minute defects that could develop into cracks occur, the boundary between the oxide phase and the phase containing Fe and Pt acts as a barrier to prevent the defects from developing, thereby preventing the defects from becoming cracks or fractures. Therefore, in the manufacturing process of the sputtering target, the occurrence of cracks or fractures can be effectively prevented during hot pressing of the mixture obtained by pulverizing and mixing the raw material powders, and further during subsequent HIP processing to increase the density of the sintered body. The average particle area of ​​the oxide phase of the sputtering target calculated using ImageJ was 3.0 μm 2 Preferably, it is 2.6 μm or less. 2 More preferably, it is 2.5 μm or less. 2 More preferably, it is 2.0 μm or less. 2 More preferably, it is 1.7 μm or less. 2 More preferably, it is 1.5 μm or less. 2 More preferably, it is 1.0 μm or less. 2 The lower limit of the average grain area of ​​the oxide phase of the sputtering target calculated using ImageJ does not need to be particularly limited, but it is preferably 0.1 μm or less, for example. 2 It may be 0.2 μm or more, for example. 2 It may be 0.3 μm or more, for example. 2 It may be 0.4 μm or more, for example. 2 It may be 0.5 μm or more, for example. 2 It may be 0.6 μm or more, for example. 2 It may be more than that.

[0020] In another aspect, the sputtering target according to an embodiment of the present invention has an oxide phase with an average circumferential length of 11.7 μm or less, calculated using ImageJ (image processing software) from a scanning electron microscope (SEM) image with a field magnification of 3000 times. When the oxide phase of the sputtering target has an average circumferential length of 11.7 μm or less, calculated using ImageJ, the oxide structure is refined, and the sputtering target has good strength. It is believed that the refined and dispersed oxide structure results in an intricate structure of the oxide phase and the phase containing Fe and Pt. Even if minute defects that could develop into cracks occur, the boundary between the oxide phase and the phase containing Fe and Pt acts as a barrier to prevent the defects from developing, thereby preventing the defects from developing into cracks or fractures. Therefore, during the manufacturing process of the sputtering target, cracks and fractures can be effectively prevented from occurring during hot pressing of the mixture obtained by pulverizing and mixing powders of raw materials, and subsequent HIP processing to increase the density of the sintered body. The average circumferential length 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, and more preferably 10.0 μm or less. The lower limit of the average circumferential length of the oxide phase of the sputtering target calculated using ImageJ does not need to be particularly limited, but may be, for example, 4.05 μm or more, for example, 4.3 μm or more, for example, 4.55 μm or more, for example, 4.8 μm or more, for example, 5.05 μm or more, or for example, 5.3 μm or more.

[0021] A method for measuring the average particle area (average size) and average circumferential length of the oxide phase of a sputtering target according to an embodiment of the present invention will be described in detail. First, a sputtering target is cut and the cross section is mirror-polished to prepare an SEM observation sample. Next, the SEM observation sample is observed using, for example, an SEM (S-3700N, manufactured by Hitachi High-Technologies Corporation). The observation settings are as follows: Image: secondary electron image, field of view magnification: 3000x, acceleration voltage: 10 to 15 kV. The average particle area and average circumferential length of the oxide phase can be evaluated by binarizing the secondary electron image obtained by the above-mentioned capture using the image analysis software ImageJ according to the following steps (1) to (7): (1) Load the SEM image with a field of view magnification of 3000x from File → Open on the ImageJ toolbar. (2) Select 8-bit from Image → Type. Draw a straight line along the scale bar, select Analyze → Set scale, and set the scale size. (3) Select the part of the image excluding the scale, and cut out the scale part with Image → Crop. (4) Select Process → Filters → Gaussian Blur, enter 2 in Sigma, and click OK. (5) Select Process → Binary → Make Binary. This completes the binarization of the image. (6) Select Analyze → Set measurement, and check Area. (7) Select Analyze → Analyze Particle, set the displayed analysis conditions to Size: 0-infinity, Circularity: 0.00-1.00, Show: nothing, check Summarize, and select OK. This will display the results, from which you can read the Average Size and the average perimeter of the oxide phase. As described above, ImageJ performs a binarization process on the imported SEM image to convert black particle portions on the SEM image to black, and the black particles are considered to be oxide phase particles, and their average particle area is calculated. In addition, areas that are darker than the surrounding area and classified as black by the binarization process are converted to black, and the black portions are considered to be oxide phase particles, and their average perimeter is calculated.The threshold value for the binarization process is automatically set based on the color histogram in the image. Figure 1 shows an example of the binarized image and the original image.

[0022] In yet another aspect, the sputtering target according to an embodiment of the present invention has a number-average equivalent circle diameter calculated using ImageJ (image processing software) on a scanning electron microscope (SEM) image with a field magnification of 3000x, assuming that the shape of the oxides in the oxide phase is circular, of 1.3 μm or less. When the number-average equivalent circle diameter calculated using ImageJ on the assumption that the shape of the oxides in the oxide phase of the sputtering target is circular is 1.3 μm or less, the oxide structure is refined, and the sputtering target has good strength. It is presumed that the refined and dispersed oxide structure results in a complex structure in which the oxide phase and the phase containing Fe and Pt are intertwined, and even if minute defects that could develop into cracks are generated, the boundary between the oxide phase and the phase containing Fe and Pt acts as a barrier to prevent the defects from developing, thereby suppressing the defects from becoming cracks or fractures. Therefore, in the manufacturing process of the sputtering target, the occurrence of cracks and breakage can be effectively suppressed during hot pressing of the mixture obtained by pulverizing and mixing the raw material powders, and further during the subsequent HIP processing for increasing the density of the sintered body, etc. The number-average diameter of the circle-equivalent diameter calculated using ImageJ assuming that the shape of the oxides in the oxide phase of the sputtering target is circular 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 circle equivalent diameter calculated using ImageJ assuming that the shape of the oxides in the oxide phase of the sputtering target is circular does not need to be particularly limited, but may be, for example, 0.55 μm or more, for example, 0.60 μm or more, for example, 0.65 μm or more, for example, 0.70 μm or more, for example, 0.75 μm or more, or for example, 0.80 μm or more.

[0023] In yet another aspect, the sputtering target according to the present invention has a measured area of ​​1261 μm in a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times. 2 The number of particles with an equivalent circular diameter of 1 μm or less per measurement area is 100 or more. 2 When the number of oxide particles having an equivalent circle diameter of 1 μm or less per target is 100 or more, the oxide structure is fine, and the sputtering target has good strength. The fine oxide structure and its dispersed presence result in a complex structure of the oxide phase and the phase containing Fe and Pt. Even if minute defects that could develop into cracks occur, the boundary between the oxide phase and the phase containing Fe and Pt acts as a barrier to prevent the defects from developing, thereby preventing the defects from becoming cracks or fractures. Therefore, in the manufacturing process of a sputtering target, the occurrence of cracks or fractures can be effectively prevented during hot pressing of the mixture obtained by pulverizing and mixing the raw material powders, and further during subsequent HIP processing to increase the density of the sintered body. The measurement area is 1261 μm. 2 The number of particles having an equivalent circular diameter of 1 μm or less per measurement area 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 There is no particular need to limit the upper limit of the number of particles having an oxide equivalent circle diameter of 1 μm or less per particle, but it may be, for example, 600 or less, for example, 580 or less, for example, 560 or less, for example, 540 or less, for example, 520 or less, or for example, 500 or less.

[0024] In yet another aspect, the sputtering target according to the present invention has a measured area of ​​1261 μm in a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times. 2The number of particles with an equivalent circular diameter of 2 μm or less per measurement area is 120 or more. 2 When the number of oxide particles having an equivalent circle diameter of 2 μm or less per target is 120 or more, the oxide structure is fine, and the sputtering target has good strength. The fine and dispersed oxide structure results in a complex structure of the oxide phase and the phase containing Fe and Pt. Even if minute defects that could develop into cracks occur, the boundary between the oxide phase and the phase containing Fe and Pt acts as a barrier to prevent the defects from developing, thereby preventing the defects from becoming cracks or fractures. Therefore, during the manufacturing process of a sputtering target, the occurrence of cracks or fractures can be effectively prevented during hot pressing of the mixture obtained by pulverizing and mixing the raw material powders, and further during subsequent HIP processing to increase the density of the sintered body. The measurement area is 1261 μm. 2 The number of particles having an equivalent circular diameter of 2 μm or less per measurement area of ​​1261 μm 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 There is no particular need to limit the upper limit of the number of particles having an oxide equivalent circle diameter of 2 μm or less per particle, but it may be, for example, 640 or less, for example, 620 or less, for example, 600 or less, for example, 580 or less, or for example, 560 or less.

[0025] A method for measuring the number-average diameter of the circle-equivalent diameter calculated assuming that the shape of the oxide in the oxide phase of the sputtering target according to the embodiment of the present invention is a circle, and a method for measuring the measurement area of ​​1261 μm in a scanning electron microscope (SEM) photograph of the sputtering target according to the embodiment of the present invention taken at a visual field magnification of 3000 times. 2The method for measuring the number of oxide particles having a circular equivalent diameter of 1 μm or less and 2 μm or less per particle is described in detail below. First, the sputtering target is cut and the cross section is mirror-polished to prepare an SEM observation sample. Next, the SEM observation sample is observed using, for example, an SEM (S-3700N, manufactured by Hitachi High-Technologies Corporation). The observation settings are as follows: Photographed image: secondary electron image, field of view magnification: 3000x, acceleration voltage: 10 to 15 kV. In the secondary electron image, the metal matrix phase appears as a brighter area than the surrounding area, and the oxide appears as a darker area than the surrounding area. Next, the photographed SEM image is binarized by the mode method using image processing software (ImageJ manufactured by the National Institutes of Health), and the area of ​​each oxide is measured using the AnalyzeParticles function of the image processing software. The area S of each oxide in the oxide phase thus obtained is used to calculate the diameter D of each oxide by the following formula (1). The diameter D is divided by the number of oxides to calculate the number-average diameter of the equivalent circle diameter, which is calculated assuming that the shape of the oxides in the oxide phase is circular. Furthermore, the diameter D is taken as the equivalent circle diameter of the oxide, and the number of particles having the equivalent circle diameter of 1 μm or less and 2 μm or less is measured.

[0026]

[0027] The binarization of ImageJ is performed in the same manner as the method for measuring the average particle area (average size) and average perimeter of the oxide phase described above, following the steps (1) to (7) above. The results are then displayed, and the area S of each oxide in the oxide phase is measured. As described above, areas that are darker than the surrounding area and are classified as black by the binarization process are converted to black, and the black areas are considered to be oxides. The threshold value for the binarization process is automatically set from the color histogram in the image. Figure 1 shows an example of the binarized image and the original image.

[0028] In yet another aspect, the sputtering target according to the present invention has a measured area of ​​1261 μm in a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times. 2The percentage of particles with an equivalent circular diameter of 1 μm or less per measurement area is 60% or more. 2 When the proportion of particles having an equivalent circular diameter of 1 μm or less per particle is 60% or more, the oxide structure is refined, and the sputtering target has good strength. The refined and dispersed oxide structure results in a complex structure of the oxide phase and the phase containing Fe and Pt. Even if minute defects that could develop into cracks occur, the boundary between the oxide phase and the phase containing Fe and Pt acts as a barrier to prevent the defects from developing, thereby preventing the defects from becoming cracks or fractures. Therefore, during the manufacturing process of a sputtering target, the occurrence of cracks or fractures can be effectively prevented during hot pressing of the mixture obtained by pulverizing and mixing raw material powders, and further during subsequent HIP processing to increase the density of the sintered body. The measurement area is 1261 μm. 2 The percentage of particles having an oxide equivalent circular diameter of 1 μm or less per measurement area of ​​1261 μm 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 having an oxide equivalent circular diameter of 1 μm or less per particle does not need to be particularly limited, but may be, for example, 89.8% or less, for example, 87.5% or less, for example, 86% or less, for example, 85% or less, for example, 84% or less, or for example, 83.4% or less.

[0029] In yet another aspect, the sputtering target according to the present invention has a measured area of ​​1261 μm in a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times. 2 The percentage of particles with an equivalent circular diameter of 2 μm or less per measurement area of ​​1261 μm is 90% or more. 2When the proportion of oxide particles having an equivalent circular diameter of 2 μm or less per particle is 90% or more, the oxide structure is refined, and the sputtering target has good strength. The refined and dispersed oxide structure results in a complex structure of the oxide phase and the phase containing Fe and Pt. Even if minute defects that could develop into cracks occur, the boundary between the oxide phase and the phase containing Fe and Pt acts as a barrier to prevent the defects from developing, thereby preventing the defects from becoming cracks or fractures. Therefore, in the manufacturing process of a sputtering target, the occurrence of cracks or fractures can be effectively prevented during hot pressing of the mixture obtained by pulverizing and mixing raw material powders, and further during subsequent HIP processing to increase the density of the sintered body. The measurement area is 1261 μm. 2 The percentage of particles having an oxide equivalent circular diameter of 2 μm or less per measurement area of ​​1261 μm 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 an oxide equivalent circle diameter of 2 μm or less per particle does not need to be particularly limited, but may be, for example, 98% or less, for example, 97% or less, for example, 96% or less, for example, 95% or less, or for example, 94% or less.

[0030] A scanning electron microscope (SEM) photograph of the sputtering target according to the embodiment of the present invention taken at a magnification of 3000 times shows a measured area of ​​1261 μm 2 The method for measuring the proportion of particles having an equivalent circular diameter of 1 μm or less and 2 μm or less per 1261 μm area of ​​the SEM photograph is described in detail below. 2 The number of particles having an equivalent circle diameter of 1 μm or less and 2 μm or less per 1261 μm area of ​​the SEM photograph is calculated in the same manner as in the measurement of the number of particles having an equivalent circle diameter of 1 μm or less and 2 μm or less per 1261 μm area of ​​the SEM photograph. 2The particle diameter is evaluated by calculating the ratio (%) of the number of particles having the above-mentioned equivalent circle diameter of 1 μm or less and the number of particles having the above-mentioned equivalent circle diameter of 2 μm or less to the total number of particles measured in the above.

[0031] In yet another aspect, the sputtering target according to an embodiment of the present invention has a bending strength of 300 MPa or more. A bending strength of 300 MPa or more can effectively suppress the occurrence of cracks and breakage during the manufacturing process. The bending strength was measured by preparing seven test specimens, measuring their three-point bending strength, and calculating the average value, as described below. Here, the three-point bending strength indicates the maximum bending stress when a load is applied to a sample by a predetermined method and the sample breaks. Breaking of a sample occurs when a crack propagates from one surface of the sample to the other surface. In other words, a high maximum bending stress means that the sample will not break even up to a high maximum bending stress. Therefore, it is believed that a high maximum bending stress makes it difficult for a crack to propagate from one surface to the other surface. In other words, by increasing the bending strength, a target can be obtained that is less susceptible to crack and breakage propagation, and cracks and breakage are less likely to propagate even when stress such as bending is applied during the manufacturing process, which is thought to effectively suppress the occurrence of cracks and breakage. The sputtering target according to the embodiment of the present invention preferably has a bending strength of 350 MPa or more, more preferably 400 MPa or more, even more preferably 450 MPa or more, and even more preferably 500 MPa or more.

[0032] The bending strength of the sputtering target according to the embodiment of the present invention can be measured as follows. First, seven test pieces are prepared by cutting the sputtering target. As a specific example of the cutting method, the sputtering target is machined to a thickness of 3 mm by lathe machining, and then cut into a size of 4 mm x 35 mm by wire discharge machining. Since the surface is oxidized, the surface is polished with #120 abrasive paper to remove the oxide film, and a sample is prepared. Next, the three-point bending strength of the test piece is measured under the following measurement conditions, and the average value is taken as the bending strength of the sputtering target. <Measurement Conditions> An A&D benchtop materials testing machine (STB-1225S) can be used as the 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 Fine Ceramics." Table 1 shows the measurement conditions for the bending strength of the sputtering target according to the embodiment of the present invention and the measurement conditions for bending strength described in JIS R 1601:2008. As shown in Table 1, the conditions for measuring the bending strength of the sputtering target according to the embodiment of the present invention are different from the conditions for measuring the bending strength described in JIS R 1601:2008 only for the "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."

[0033]

[0034] A sputtering target according to an embodiment of the present invention may be: 1. 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 balance; 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 element (3) is 0.5 to 15 mol %, the balance of (4) is an oxide which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, and the target satisfies one, two, three, four, five, six, seven, or eight of the following items A to H. A: The average particle area (average size) of the oxide phase calculated using ImageJ using an SEM image with a field magnification of 3000 times is 4.0 μm 2 B: The average perimeter of the oxide phase calculated using ImageJ from an SEM image at a magnification of 3000x is 11.7 μm or less. C: The bending strength is 300 MPa or more. D: The number-average diameter of the equivalent circle diameter calculated using ImageJ from an SEM image at a magnification of 3000x, assuming that the shape of the oxide in the oxide phase is circular, is 1.3 μm or less. E: The measured area of ​​a scanning electron microscope (SEM) photograph taken at a magnification of 3000x is 1261 μm 2 F: The number of particles having an equivalent circle diameter of 1 μm or less per unit area is 100 or more. F: The measured area of ​​a scanning electron microscope (SEM) photograph taken at a magnification of 3000 times is 1261 μm. 2 G: The number of particles having an equivalent circle diameter of 2 μm or less per unit area is 120 or more. G: The measured area of ​​a scanning electron microscope (SEM) photograph taken at a magnification of 3000 times is 1261 μm. 2 The percentage of particles having an equivalent circular diameter of 1 μm or less per unit area is 60% or more. H: A scanning electron microscope (SEM) photograph taken at a magnification of 3000 times has a measured area of ​​1261 μm. 2 The proportion of particles having an equivalent circle diameter of 2 μm or less per oxide is 90% or more.

[0035] <Sputtering Target Assembly> The sputtering target according to the embodiment of the present invention may be bonded to a backing plate as needed to form a sputtering target assembly. The sputtering target assembly can be mounted in a sputtering apparatus for use. Indium or indium tin can be used as the brazing material. The sputtering target according to the embodiment of the present invention may be mounted directly in a sputtering apparatus for use 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 these (e.g., Cu-Ni-Si alloys (e.g., C18000, etc.), CuZn alloys, and CuCr alloys). It is preferable that the material of the backing plate has high thermal conductivity, and from this perspective, Cu is suitable.

[0036] <Method for Manufacturing a Sputtering Target> A method for manufacturing a sputtering target according to an embodiment of the present invention will be described in detail below. Sputtering targets according to an embodiment of the present invention can be manufactured by a powder sintering method. First, powders of the respective metal elements are prepared. Alternatively, alloy powders of these metals (e.g., Fe—Pt powder) may be used instead of the powders of the respective metal elements. The purity of these raw materials is typically 2N (99% by mass) or higher, preferably 3N (99.9% by mass) or higher, and more preferably 4N (99.99% by mass) or higher. If the purity is lower than 2N, the sintered compact will contain a large amount of impurities, which can lead to problems such as an inability to obtain the desired physical properties (e.g., particle generation due to arcing). These raw materials can be appropriately prepared based on the composition and purity of the desired sintered compact.

[0037] These metal powders are then weighed to achieve the desired composition and mixed using a mixing device that also serves as a mill. Non-magnetic particles may also be mixed with the metal powder at this stage. Mixing devices such as a ball mill or mortar can be used, but a powerful mixing method such as a ball mill is preferable. Considering the problem of oxidation during mixing, mixing is preferably performed in an inert gas atmosphere or vacuum. The mixing time is set to 0.1 to 48 hours. Increasing the raw material mixing time can reduce the average particle area of ​​the oxide phase. On the other hand, shortening the raw material mixing time can increase the average particle area of ​​the oxide phase. From this perspective, the average particle area of ​​the oxide phase is controlled by adjusting the raw material mixing time. Increasing the raw material mixing time can reduce the average circumferential length of the oxide phase. On the other hand, shortening the raw material mixing time can increase the average circumferential length of the oxide phase. From this perspective, the average circumferential length of the oxide phase is controlled by adjusting the raw material mixing time. Increasing the raw material mixing time can reduce the oxide size of the oxide phase, thereby increasing the bending strength of the sputtering target. Oxides are known to have lower toughness than metals. In sintered bodies having a structure in which oxides are dispersed in the base metal, cracks often originate from the oxide phase, which has low toughness. By dispersing these oxide particles more finely, the proportion of relatively coarse oxides in the sintered body is reduced, and crack generation is suppressed, which is expected to improve bending strength. On the other hand, shortening the mixing time of the raw materials can increase the size of the oxides in the oxide phase. From this perspective, the bending strength of the sputtering target can be controlled by adjusting the mixing time of the raw materials. Furthermore, by increasing the mixing time of the raw materials, the number-average circle-equivalent diameter calculated assuming that the shape of the oxide in the oxide phase is circular can be reduced. On the other hand, by shortening the mixing time of the raw materials, the number-average circle-equivalent diameter calculated assuming that the shape of the oxide in the oxide phase is circular can be increased. From this perspective, adjusting the mixing time of the raw materials can control the number-average circle-equivalent diameter calculated assuming that the shape of the oxide in the oxide phase is circular.In addition, by increasing the mixing time of the raw materials, the measured area of ​​the scanning electron microscope (SEM) photograph taken at a magnification of 3000 times was 1261 μm. 2 On the other hand, by shortening the mixing time of the raw materials, it is possible to increase the number or proportion of particles having an oxide equivalent circle diameter of 1 μm or less or 2 μm or less per unit area. 2 From this perspective, by adjusting the mixing time of the raw materials, it is possible to reduce the number or the proportion of particles having an oxide equivalent circle diameter of 1 μm or less or 2 μm or less per unit area. 2 The number or proportion of particles having an oxide equivalent circle diameter of 1 μm or less or 2 μm or less per unit area is controlled.

[0038] The mixed powder thus obtained is molded and sintered using a hot press to produce a sintered body. The molding and sintering method is not limited to hot pressing; plasma discharge sintering and hot isostatic sintering can also be used. The sintering conditions are 650 to 1400°C and 0.5 to 12 hours. Increasing the sintering temperature and / or lengthening the sintering time can increase the average particle area of ​​the oxide phase. On the other hand, decreasing the sintering temperature and / or shortening the sintering time can decrease the average particle area of ​​the oxide phase. From this perspective, the average particle area of ​​the oxide phase is controlled by adjusting the sintering temperature and sintering time. Furthermore, increasing the sintering temperature and / or lengthening the sintering time can increase the average circumferential length of the oxide phase. On the other hand, decreasing the sintering temperature and / or shortening the sintering time can decrease the average circumferential length of the oxide phase. From this perspective, the average circumferential length of the oxide phase is controlled by adjusting the sintering temperature and sintering time. Furthermore, increasing the sintering temperature and / or lengthening the sintering time can increase the oxide size of the oxide phase. On the other hand, by lowering the sintering temperature and / or shortening the sintering time, the oxides in the oxide phase can be made smaller. From this perspective, by adjusting the sintering temperature and sintering time, the size of the oxides in the oxide phase can be controlled, thereby controlling the bending strength of the sputtering target. Furthermore, by increasing the sintering temperature and / or lengthening the sintering time, the number-average circle-equivalent diameter calculated assuming that the shape of the oxides in the oxide phase is circular can be increased. On the other hand, by lowering the sintering temperature and / or shortening the sintering time, the number-average circle-equivalent diameter calculated assuming that the shape of the oxides in the oxide phase is circular can be decreased. From this perspective, by adjusting the sintering temperature and sintering time, the number-average circle-equivalent diameter calculated assuming that the shape of the oxides in the oxide phase is circular can be controlled. Furthermore, by increasing the sintering temperature and / or lengthening the ... measured area of ​​1261 μm in a scanning electron microscope (SEM) photograph taken at a field magnification of 3000x can be reduced. 2On the other hand, if the sintering temperature is lowered and / or the sintering time is shortened, the number or proportion of particles having an oxide equivalent circle diameter of 1 μm or less per unit area can be increased. 2 From this viewpoint, by adjusting the sintering temperature and sintering time, it is possible to reduce the number or the proportion of particles having an equivalent circle diameter of 1 μm or less per unit area of ​​1261 μm in a scanning electron microscope (SEM) photograph taken at a magnification of 3000 times. 2 The number or proportion of particles having an oxide equivalent circle diameter of 1 μm or less or 2 μm or less per unit area is controlled.

[0039] The sintered body is then removed from the hot press and subjected to HIP (Hot Isostatic Pressing). HIP is an effective method for improving the density of the sintered body. The holding temperature during HIP is 650-1100°C, the holding time is 0.5-12 hours, and the pressure is 100 MPa or more. The sintered body thus obtained is then machined into the desired shape on a lathe to produce a sputtering target.

[0040] <Film formation method using a sputtering target> Using the sputtering target according to the embodiment of the present invention, it is possible to form a thin film that mainly constitutes a magnetic recording medium. Specifically, using a sputtering device, the surface of the sputtering target is sputtered with accelerated argon ions, particles (sputtered particles) are emitted from the sputtering target, and the sputtered particles are deposited on the surface of a substrate that has been placed in a position opposite the sputtering target, thereby forming a thin film on the surface of the substrate. Sputtering conditions can be set appropriately depending on the desired film thickness, composition, etc.

[0041] Examples of the present invention are given below, but these examples are provided for a better understanding of the present invention and its advantages, and are not intended to limit the invention.

[0042] Example 1 A sputtering target according to Example 1 was manufactured by the following manufacturing method. Fe powder, Pt powder, Ag powder, and SiO2 powder were prepared as raw material powders and weighed out to have a composition of (30-45)Fe-(30-45)Pt-(5-15)Ag-(5-25)SiO2 (mol %). The raw material powders were adjusted so that the total composition was 100 mol %. Amorphous powder was used for the SiO2 powder. Next, the weighed Fe powder, Pt powder, Ag powder, and SiO2 powder were placed in a 5 L ball mill pot together with zirconia balls and mixed for 4 hours.

[0043] Next, the mixed powder removed from the ball mill pot was filled into a carbon mold and hot-pressed. The hot-pressing conditions were a vacuum atmosphere, a heating rate of 300°C / hour, a holding temperature (sintering temperature) of 900°C, and a holding time (sintering time) of 2 hours. A pressure of 30 MPa was applied from the start of heating to the end of the holding period. After the holding period, the sintered body was allowed to cool naturally in the chamber. The sintered body removed from the hot-pressing mold was then subjected to HIP processing. The HIP processing conditions were a heating rate of 300°C / hour, a holding temperature of 850°C, and a holding time of 2 hours. The Ar gas pressure was gradually increased from the start of heating, and the sintered body was pressurized at 150 MPa during the holding period. After the holding period, the sintered body was allowed to cool naturally in the furnace. In this way, a sputtering target according to Example 1 was produced.

[0044] <Examples 2 to 8, Comparative Example 1> Sputtering targets according to 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 set under the conditions shown in Table 2.

[0045] Average particle area and average perimeter of the oxide phase: First, the sputtering target was cut and the cross section was mirror-polished to prepare an SEM observation sample. Next, the SEM observation sample was observed using an SEM (S-3700N, manufactured by Hitachi High-Technologies Corporation). The observation settings were as follows: Image: secondary electron image, field of view magnification: 3000x, acceleration voltage: 10-15 kV. The average particle area and average perimeter of the oxide phase were evaluated by binarizing the secondary electron image obtained by the above-mentioned capture using the image analysis software ImageJ according to the following steps (1) to (7). (1) Load the SEM image with a field of view magnification of 3000x from File → Open on the ImageJ toolbar. (2) Select 8-bit from Image → Type. Draw a line along the scale bar, select Analyze → Set scale, and set the scale size. (3) Select the portion of the image excluding the scale, and crop the scale portion using Image → Crop. (4) Select Process → Filters → Gaussian Blur, enter 2 for Sigma, and click OK. (5) Select Process → Binary → Make Binary. This completes the binarization of the image. A screenshot of the setting conditions is shown in Figure 2. (6) Select Analyze → Set measurement and check Area. (7) Select Analyze → Analyze Particle, and set the displayed analysis conditions to Size: 0-infinity, Circularity: 0.00-1.00, Show: nothing, check Summarize, and select OK. The results are then displayed, and the Average Size value is read from the display. After capturing the SEM image using ImageJ as described above, a binarization process was performed to convert black particle areas in the SEM image to black, and the black particles were considered to be oxide phase particles, and their average particle area was calculated. Furthermore, areas that were classified as black by the binarization process and were darker than their surroundings were converted to black, and the black areas were considered to be oxide phase particles, and their average perimeter was calculated. The threshold value for the binarization process was automatically set from the color histogram in the image.

[0046] The number-average diameter of the circle-equivalent diameter calculated assuming that the shape of the oxide in the oxide phase is circular, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a visual field magnification of 3000 times is 1261 μm 2 First, the sputtering target was cut and the cross section was mirror-polished to prepare an SEM observation sample. Next, the SEM observation sample was observed using an SEM (S-3700N, manufactured by Hitachi High-Technologies Corporation). The observation settings were as follows: Image: secondary electron image, field of view magnification: 3000x, acceleration voltage: 10-15 kV. In the secondary electron image, the metal matrix phase appeared as a brighter area than the surrounding area, and the oxide appeared as a darker area than the surrounding area. Next, the captured SEM image was binarized by the mode method using image processing software (ImageJ manufactured by the National Institutes of Health), and the area of ​​each oxide was measured using the AnalyzeParticles function of the image processing software. From the area S of each oxide in the oxide phase obtained in this way, the diameter D of each oxide was calculated using the following formula (1): The diameter D was divided by the number of oxides to calculate the number-average equivalent circle diameter, which was calculated assuming that the shape of the oxides in the oxide phase was circular. The diameter D was also taken as the equivalent circle diameter of the oxide, and the number of particles having an equivalent circle diameter of 1 μm or less or 2 μm or less was measured.

[0047]

[0048] The ImageJ was binarized according to the procedures (1) to (7) above. The results were displayed, and the area S of each oxide in the oxide phase was measured. As described above, areas that were darker than the surrounding areas and classified as black by the binarization process were converted to black, and the black areas were considered to be oxides. The threshold value for the binarization process was automatically set based on the color histogram in the image.

[0049] ・Measurement area of ​​scanning electron microscope (SEM) photograph taken at 3000x magnification: 1261 μm 2First, the ratio of the number of particles having an oxide equivalent circle diameter of 1 μm or less or 2 μm or less per 1261 μm area of ​​the SEM photograph 2 The number of particles having an equivalent circle diameter of 1 μm or less or 2 μm or less per 1261 μm area was calculated in the same manner as in the measurement of the number of particles having an equivalent circle diameter of 1 μm or less or 2 μm or less per 1261 μm area. 2 The evaluation was carried out by calculating the ratio (%) of the number of particles having the above-mentioned equivalent circular diameter of 1 μm or less and the number of particles having the above-mentioned equivalent circular diameter of 2 μm or less to the total number of particles measured in the above.

[0050] The oxide volume ratio was evaluated by calculating the volume of each component contained in the target as follows: (content of each material: mol) x (molecular weight of each material: g / mol) x (reciprocal of density of each material: cm 3 Next, the volume fraction of oxide was calculated by dividing the total volume of only oxides among the components by the total volume of all components.

[0051] Bending Strength Seven test pieces were prepared by cutting out samples of the sputtering target. The sputtering target was machined to a thickness of 3 mm by lathe machining, and then cut into a size of 4 mm x 35 mm by wire discharge machining. Subsequently, since the surface was oxidized, the surface was polished with #120 abrasive paper to remove the oxide film, and a sample was prepared. Next, three-point bending strength was measured under the following measurement conditions, and the average value was taken as the bending strength of the sputtering target. Bending strength tests were not conducted for Examples 3 to 8. <Measurement Conditions> A benchtop materials testing machine (STB-1225S) manufactured by A&D Co., Ltd. was used as the measuring device. The bending strength of the sputtering target according to this test example was measured with reference to JIS R 1601:2008 "Test Method for Bending Strength of Fine Ceramics," and was performed under the "Measurement Conditions for this Embodiment" shown in Table 1 above. That is, as shown in Table 1 above, the conditions for measuring the bending strength of the sputtering target according to this test example differ from the conditions for measuring bending strength described in JIS R 1601:2008 only with respect to the "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."

[0052] Cracks The surface of each sputtering target of each example and comparative example was visually inspected to determine whether or not any cracks were present. This evaluation was used to determine whether or not the occurrence of cracks or breakage during the manufacturing process was suppressed. The evaluation results are shown in Tables 2 and 3.

[0053]

[0054]

[0055] <Discussion> According to Tables 2 and 3, the sputtering targets according to Examples 1 to 8 each contained (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 balance, in which the atomic ratio of (1) Fe to (2) Pt was 34 to 55 at %, the total concentration of (1) Fe and (2) Pt was 50 mol % or more, the content of the element (3) was 0.5 to 15 mol % in total, and the balance of (4) was an oxide, and the volume fraction of the oxide was 40 vol. % or more. In addition, the sputtering targets according to Examples 1 to 8 each had an average particle area (average size) of 4.0 μm , calculated using ImageJ on an SEM image with a visual field magnification of 3000 times. 2 or less. Therefore, the bending strength was good, and the occurrence of cracks and breakage during the manufacturing process was suppressed. Furthermore, the sputtering targets according to Examples 1 and 2 each had a bending strength of 300 MPa or more. Therefore, the occurrence of cracks and breakage during the manufacturing process was suppressed. Furthermore, the sputtering targets according to Examples 1 to 8 each had an average circumferential length of the oxide phase calculated using ImageJ with an SEM image at a visual field magnification of 3000 times, of 11.7 μm or less. Therefore, the bending strength was good, and the occurrence of cracks and breakage during the manufacturing process was suppressed. Furthermore, the sputtering targets according to Examples 1 to 8 each had a number-average diameter of equivalent circle calculated using ImageJ with an SEM image at a visual field magnification of 3000 times, assuming that the shape of the oxide in the oxide phase is circular, of 1.3 μm or less. Therefore, the bending strength was good, and the occurrence of cracks and breakage during the manufacturing process was suppressed. The sputtering targets according to Examples 1 to 8 each had a measured area of ​​1261 μm in a scanning electron microscope (SEM) photograph taken at a visual field magnification of 3000 times. 2 The number of particles having an equivalent circle diameter of 1 μm or less per unit area was 100 or more. 2The number of particles having an equivalent circle diameter of 2 μm or less per unit area was 120 or more. 2 The percentage of particles having an oxide equivalent circle diameter of 1 μm or less per unit area was 60% or more. 2 The proportion of particles having an equivalent circular diameter of 2 μm or less per particle was 90% or more, which resulted in good bending strength and suppressed the occurrence of cracks and breakage during the manufacturing process.

[0056] In contrast, in Comparative Example 1, the average particle area (average size) of the oxide phase calculated using ImageJ using an SEM image with a visual field magnification of 3000 times was 4.0 μm 2 . Therefore, the bending strength was poor, and cracks and breakage occurred during the manufacturing process. Furthermore, in Comparative Example 1, the average perimeter of the oxide phase calculated using ImageJ with an SEM image at a magnification of 3000x exceeded 11.7 μm. Therefore, the bending strength was poor, and cracks and breakage occurred during the manufacturing process. Furthermore, in Comparative Example 1, the bending strength was less than 300 MPa. Therefore, cracks and breakage occurred during the manufacturing process. Furthermore, in Comparative Example 1, the number-average diameter of the circle-equivalent diameter calculated using ImageJ with an SEM image at a magnification of 3000x, assuming that the shape of the oxide in the oxide phase is circular, exceeded 1.3 μm. Therefore, the bending strength was poor, and cracks and breakage occurred during the manufacturing process. Furthermore, in Comparative Example 1, the number-average diameter of the circle-equivalent diameter calculated using ImageJ with an SEM image at a magnification of 3000x ... 2 The number of particles with an equivalent circular diameter of 1 μm or less per unit area is less than 100, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a magnification of 3000 times is 1261 μm. 2 The number of particles with an equivalent circular diameter of 2 μm or less per unit area is less than 120, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a magnification of 3000 times is 1261 μm. 2The percentage of particles with an equivalent circular diameter of 1 μm or less per oxide is less than 60%, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a magnification of 3000 times is 1261 μm 2 The proportion of particles having an equivalent circular diameter of 2 μm or less per particle was less than 90%, resulting in poor bending strength and the occurrence of cracks and breakage during the manufacturing process.

[0057] According to one embodiment of the present invention, a sputtering target and a sputtering target assembly that can effectively suppress the occurrence of cracks and breakages during the manufacturing process can be obtained, which may contribute to the advancement of thin film formation technologies by sputtering used in 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, which is to "Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation."

Claims

1. A ferroelectric material having (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at%, the total concentration of the (1) Fe and the (2) Pt is 50 mol% or more, the content of the (3) element is 0.5 to 15 mol% in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol.% or more, and the average grain area (Average grain area) of the oxide phase calculated using ImageJ using a SEM image with a field magnification of 3000 times. size) is 4.0 μm 2 The sputtering target is as follows:

2. A composite material having (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, A sputtering target having an average perimeter of an oxide phase of 11.7 μm or less, calculated using ImageJ on an SEM image with a field magnification of 3000 times.

3. A sputtering target having (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance of the (4) is an oxide which may selectively contain impurities, the volume fraction of the oxide is 40 vol. % or more, and the bending strength is 300 MPa or more.

4. A composite material having (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at %, the total concentration of the (1) Fe and the (2) Pt is 50 mol % or more, the content of the (3) element is 0.5 to 15 mol % in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol. % or more, A sputtering target having a number-average circle-equivalent diameter of 1.3 μm or less, calculated using ImageJ on an SEM image with a visual field magnification of 3000 times and assuming that the shape of oxides in an oxide phase is circular.

5. A composite material having (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at%, the total concentration of the (1) Fe and the (2) Pt is 50 mol% or more, the content of the (3) element is 0.5 to 15 mol% in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol.% or more, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 2 The sputtering target has 100 or more oxide particles each having a circular equivalent diameter of 1 μm or less.

6. A composite material having (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at%, the total concentration of the (1) Fe and the (2) Pt is 50 mol% or more, the content of the (3) element is 0.5 to 15 mol% in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol.% or more, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 2 The sputtering target has 120 or more particles each having an oxide equivalent circle diameter of 2 μm or less.

7. A composite material having (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at%, the total concentration of the (1) Fe and the (2) Pt is 50 mol% or more, the content of the (3) element is 0.5 to 15 mol% in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol.% or more, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 2 The sputtering target according to claim 1, wherein the percentage of particles having an oxide equivalent circle diameter of 1 μm or less per unit area is 60% or more.

8. A composite material having (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 balance, wherein the atomic ratio of the (1) Fe to the (2) Pt is 34 to 55 at%, the total concentration of the (1) Fe and the (2) Pt is 50 mol% or more, the content of the (3) element is 0.5 to 15 mol% in total, the balance of the (4) is an oxide, which may selectively contain impurities, and the volume fraction of the oxide is 40 vol.% or more, and the measured area of ​​a scanning electron microscope (SEM) photograph taken at a field magnification of 3000 times is 1261 μm 2 The sputtering target according to claim 1, wherein the percentage of particles having an oxide equivalent circle diameter of 2 μm or less per unit area is 90% or more.

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

10. The sputtering target according to claim 9, wherein the oxide further contains one or more oxides of elements 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: a sputtering target according to any one of claims 1 to 8; and a backing plate bonded to the sputtering target.

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