Sputtering target for magnetic material, sputtering target assembly for magnetic material, and manufacturing method for sputtering target for magnetic material

Abstract

Provided are: a sputtering target for a magnetic material in which re-deposition film peeling can be effectively suppressed; a sputtering target assembly for a magnetic material; and a manufacturing method for a sputtering target for a magnetic material. The sputtering target for a magnetic material has a sputtering region and a non-sputtering region, wherein the arithmetic mean peak curvature Spc of the surface of the non-sputtering region is at least 3200 mm-1.

Description

Sputtering target for magnetic material, sputtering target assembly for magnetic material, and method for manufacturing sputtering target for magnetic material

[0001] The present invention relates to a sputtering target for a magnetic material, a sputtering target assembly for a magnetic material, and a method for manufacturing a sputtering target for a magnetic material, and mainly relates to a sputtering target for manufacturing films for HDDs.

[0002] For example, the layers of hard disks 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 consisting of ferromagnetic alloys, such as Co-Cr, Co-Pt, Co-Cr-Pt, and Fe-Pt, which have Co or Fe as their main components, and non-magnetic inorganic materials. Thin films for magnetic recording media such as hard disks are often produced by sputtering targets containing the above materials, due to their high productivity.

[0003] Sputtering is a technique for forming a thin film on the surface of a substrate by sputtering the surface of a sputtering target, which serves as the sputtering source, with accelerated argon ions, releasing particles (sputter particles) from the sputtering target and depositing the sputter particles on the surface of a substrate that has been placed in an opposing position.

[0004] Some of the sputtered particles may redeposit at specific locations on the sputtering target to form a laminate (also called a redeposited film). If this redeposited film peels off from the sputtering target, it can cause arcing (abnormal discharge) during sputtering, increase the number of particles during sputtering, and cause problems such as contamination of the thin film, resulting in a lower product yield.

[0005] To address this problem, Patent Document 1 discloses that the region of the sputtering target where the redeposition film is formed is roughened by blasting with glass beads. It also discloses that this makes it possible to prevent the redeposition film from peeling off from the roughened surface. Patent Document 2 also discloses roughening the sputtering target. Patent Document 2 also discloses that the region to be roughened is within a range from the outer periphery (0%) of the sputtering target to a position 2 to 13% in the center direction, and / or within a range from the center (0%) to a position 12 to 33% in the outer periphery direction.

[0006] Japanese Patent Laid-Open No. 4-301074 Japanese Patent Laid-Open No. 2018-141202

[0007] Both Patent Documents 1 and 2 merely mention controlling the arithmetic mean roughness Ra, and there is room for improvement in terms of suppressing peeling of the redeposition film.

[0008] Therefore, an object of an embodiment of the present invention is to provide a sputtering target for magnetic materials, a sputtering target assembly for magnetic materials, and a method for manufacturing a sputtering target for magnetic materials that can effectively suppress peeling of a redeposition film.

[0009] The above-mentioned problems are solved by the present invention, which is specified as follows: (1) A sputtering target for magnetic materials having a sputtering region and a non-sputtering region, wherein the arithmetic mean curvature Spc of peaks on the surface of the non-sputtering region is 3200 mm -1(2) A sputtering target for a magnetic material according to (1), wherein the developed area ratio Sdr of the surface of the non-sputtering region is 4.5 or more. (3) A sputtering target for a magnetic material according to (1) or (2), wherein the surface roughness Sa of the non-sputtering region is 10 to 40 μm. (4) A sputtering target for a magnetic material according to any one of (1) to (3), wherein the maximum height Sz of the non-sputtering region is 100 to 250 μm. (5) A sputtering target for a magnetic material according to any one of (1) to (4), wherein the root mean square height Sq of the non-sputtering region is 3 to 45 μm. (6) A sputtering target for a magnetic material according to any one of (1) to (5), which contains at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, O, Mg, Zn, Ag, Cu, Ni, Ta, Nb, V, W, Mn, Bi, Ge, and Ir in its composition. (7) A sputtering target assembly for a magnetic material, comprising: the sputtering target for a magnetic material according to any one of (1) to (6); and a backing plate bonded to the sputtering target for a magnetic material. (8) A method for manufacturing a sputtering target for a magnetic material having a sputtering region and a non-sputtering region, wherein the non-sputtering region has a peak arithmetic mean curvature Spc of 3200 mm -1 A method for producing a sputtering target for a magnetic material, comprising the step of forming the surface as described above.

[0010] According to the embodiments of the present invention, it is possible to provide a sputtering target for a magnetic material, a sputtering target assembly for a magnetic material, and a method for manufacturing a sputtering target for a magnetic material, which are capable of effectively suppressing peeling of a redeposition film.

[0011] Figures 1(A) and 1(B) are plan views each showing a schematic representation of a disk-shaped sputtering target. Figure 2 is an optical microscope photograph of the surface of the non-sputtering region of Example 3. (A) is a photograph of the appearance of the sample surface after lacquer spray application in Example 3. (B) is a photograph of the appearance of the sample surface after cutting out a 1 mm square lattice in Example 3. (C) is a photograph of the appearance of the sample surface after a peel test in Example 3. (D) is a photograph of the appearance of the sample surface after a peel test in Comparative Example 7.

[0012] Next, embodiments of the present invention will be described in detail with reference to the drawings. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes and improvements may be made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0013] <Sputtering target for magnetic material> The shape of the sputtering target for magnetic material 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. In this specification, the sputtering target for magnetic material may also be simply referred to as a sputtering target.

[0014] The sputtering target according to this embodiment is used, for example, to form magnetic recording layers and thin films in HDDs. The material of the sputtering target according to this embodiment is not particularly limited, but may include at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, O, Mg, Zn, Ag, Cu, Ni, Ta, Nb, V, W, Mn, Bi, Ge, and Ir. Alternatively, the sputtering target may include an alloy containing at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, Mg, Zn, Ag, Cu, Ni, Ta, Nb, V, W, Mn, Bi, Ge, and Ir. The sputtering target may also be made of a material containing an alloy particle phase and a non-magnetic material. The non-magnetic material may be one or more selected from carbon, oxides, nitrides, and carbides.

[0015] The sputtering target according to the embodiment of the present invention mainly has a front surface, a back surface, and a side surface. The front surface is subjected to a roughening treatment described below. Therefore, the front surface has a sputtering region and a non-sputtering region. The sputtering region is a region on the surface of the sputtering target that is sputtered by bombarding accelerated argon ions, and the non-sputtering region is a region on the surface of the sputtering target other than the sputtering region. This non-sputtering region is a region where some of the sputtered particles redeposit to form a redeposited film, and in order to effectively suppress peeling of the redeposited film, the sputtering target according to the embodiment of the present invention is subjected to a very distinctive roughening treatment.

[0016] Specific examples of the sputtering region and the non-sputtering region of the sputtering target according to the embodiment of the present invention are shown in Figures 1(A) and 1(B), which are plan views schematically showing sputtering targets 10a and 10b formed in a disk shape, respectively.

[0017] In the sputtering target 10a shown in FIG. 1A, only the peripheral portion of the surface of the sputtering target 10a, where the redeposition film is formed, is a non-sputtering region 12a, while the remaining regions, including the central portion, are sputtering regions 11a. The peripheral non-sputtering region 12a is preferably formed with a uniform width of a predetermined size along the circumferential direction of the surface of the sputtering target 10a. The area ratio of the peripheral non-sputtering region 12a is not particularly limited as long as it covers at least the position where the redeposition film is formed. Furthermore, the sputtering target 10a may have a non-sputtering region that is roughened not only on the peripheral portion of the surface as described above, but also on the entire or part of the side surface. Even in this case, the entire or part of the side surface non-sputtering region has the same characteristics as the non-sputtering region described below.

[0018] In the sputtering target 10b shown in FIG. 1B, the peripheral portion of the surface of the sputtering target 10b where the redeposition film is formed is a non-sputtering region 12b, and the central portion of the surface is also a non-sputtering region 13b. The area other than these non-sputtering regions 12b and 13b is a sputtering region 11b. The peripheral non-sputtering region 12b is preferably formed with a uniform width of a predetermined size along the circumferential direction of the surface of the sputtering target 10b. The area ratios of the central non-sputtering region 13b and the peripheral non-sputtering region 12b are not particularly limited as long as they cover at least the position where the redeposition film is formed. Furthermore, only the central portion of the surface of the sputtering target 10b may be roughened. Furthermore, the sputtering target 10b may have a non-sputtering region where the entire surface or a portion of the side surface is roughened, in addition to the peripheral and central portions of the surface as described above. In this case, the entire surface or a portion of the side surface has the same characteristics as the non-sputtering region described below.

[0019] The non-sputtering region 12a of the sputtering target according to the embodiment of the present invention has a surface peak arithmetic mean curvature Spc of 3200 mm -1 The arithmetic mean curvature Spc of the peaks on the surface is controlled to 3200 mm or more. If the arithmetic mean curvature Spc of the peaks on the surface is small, it indicates that the points that come into contact with other objects are rounded, and if the arithmetic mean curvature Spc is large, it indicates that the points that come into contact with other objects are sharp. -1 If the surface roughness of the non-sputtered region 12a is higher, the adhesion of the redeposited film formed in the non-sputtered region is improved, and peeling of the redeposited film can be effectively suppressed. As a result, the incorporation of particles during sputtering is suppressed, and the product yield can be improved. In addition, the arithmetic mean curvature Spc of the peaks on the surface of the non-sputtered region 12a is 6000 mm. -1 If the thickness exceeds 1000 nm, the convex portions will be too sharp, which may easily induce arcing. Therefore, the arithmetic mean curvature Spc of the peaks on the surface of the non-sputtering region 12a is set to 3200 to 6000 mm. -1The arithmetic mean curvature Spc of the peaks on the surface of the non-sputtered region 12a is preferably 3500 to 5500 mm -1 More preferably, it is 3700 to 5100 mm -1 The arithmetic mean curvature Spc of the peaks on the surface of the non-sputtered region 12a can be measured using a laser microscope in accordance with ISO-25178.

[0020] The developed area ratio Sdr of the surface of the non-sputtered region 12a is preferably 4.5 or greater. The developed area ratio Sdr represents the degree to which the developed area (surface area) of a given region has increased relative to the area of ​​that given region; for example, the developed area ratio Sdr of a completely flat surface is 0. If the developed area ratio Sdr of the surface of the non-sputtered region 12a is 4.5 or greater, the roughness of the non-sputtered region 12a is further increased, thereby increasing the contact area with the redeposited film and improving the adhesion of the redeposited film. The developed area ratio Sdr of the surface of the non-sputtered region 12a is more preferably 5.0 or greater. There is no particular upper limit to the developed area ratio Sdr of the surface of the non-sputtered region 12a, but it may be 10.0 or less, or even 9.0 or less. The developed area ratio Sdr of the surface of the non-sputtered region 12a can be measured using a laser microscope in accordance with ISO-25178.

[0021] The surface roughness Sa of the non-sputtering region 12a is preferably 10 to 40 μm. When the surface roughness Sa of the non-sputtering region 12a is 10 μm or more, the roughness of the non-sputtering region 12a is further increased, thereby improving the adhesion of the redeposited film. When the surface roughness Sa of the non-sputtering region 12a exceeds 40 μm, this means that there are too many protruding portions, which are portions that protrude away from the surface of the sputtering target. The increased number of protruding portions may induce arcing. The surface roughness Sa of the non-sputtering region 12a is more preferably 15 to 35 μm, and even more preferably 18 to 33 μm. The surface roughness Sa of the non-sputtering region 12a can be measured using a laser microscope in accordance with ISO-25178. Furthermore, while the average surface roughness Ra is evaluated using a "line," the surface roughness Sa is evaluated using a "plane." When measuring average roughness Ra, the measurement results vary depending on which part is set as the measurement target. For example, if the measurement target is set along a predetermined area and Ra is measured, Ra will be smaller than when the measurement target is set across the predetermined area. Therefore, by using surface roughness Sa, the variation in Sa depending on the setting position of the measurement target is reduced, thereby improving the accuracy of control of the surface shape of the sputtering target. As a result, the quality stability of the sputtering target can be improved.

[0022] The maximum height Sz of the non-sputtered region 12a is preferably 100 to 250 μm. If the maximum height Sz of the non-sputtered region 12a is 100 μm or more, the difference in elevation of the non-sputtered region 12a becomes large, and when a redeposited film is formed in the non-sputtered region 12a, the redeposited film is more likely to be secured at high and low positions in the non-sputtered region 12a. Therefore, the redeposited film is less likely to peel off from the non-sputtered region. If the maximum height Sz of the non-sputtered region 12a exceeds 250 μm, there is a high possibility that very large convex portions will be present. This may therefore be a factor in inducing arcing during sputtering. The maximum height Sz of the non-sputtered region 12a is more preferably 110 to 210 μm, and even more preferably 120 to 200 μm. The maximum height Sz of the non-sputtered region 12a can be measured using a laser microscope in accordance with ISO-25178.

[0023] The root-mean-square height Sq of the non-sputtered region 12a is preferably 3 to 45 μm. Since Sq represents the standard deviation of roughness, a small Sq indicates small roughness itself. Therefore, it is preferable that the root-mean-square height Sq of the non-sputtered region 12a be 3 μm or more. If the root-mean-square height Sq of the non-sputtered region 12a is 45 μm or less, it indicates a small standard deviation of surface roughness, indicating uniform unevenness, and is advantageous in terms of preventing arcing. If the root-mean-square height Sq of the non-sputtered region 12a exceeds 45 μm, it indicates large variation in surface height, making it more likely that specifically high positions will exist. This increases the likelihood of arcing. The root-mean-square height Sq of the non-sputtered region 12a is more preferably 15 to 40 μm, and even more preferably 18 to 39 μm. The root mean square height Sq of the non-sputtered region 12a can be measured using a laser microscope in accordance with ISO-25178.

[0024] The above-mentioned Spc, Sdr, Sa, Sz, and Sq can be measured using a laser microscope (Keyence VK-X3000). The procedure is as follows. With the VK-X3000, a 10x objective lens, 1.5x digital zoom, and 24x screen magnification are used to acquire a 360x (10x x 1.5x x 24x) image. The analysis software used is the multi-file analysis application version 3.3.1.85 included with the VK-X3000. First, select surface roughness measurement as the measurement mode, and then select the desired roughness parameters and area. When selecting the area, specify a range (896 μm x 672 μm) from the acquired image (360x image). Note that the above-mentioned area is determined by performing this range specification operation on the laser microscope. Next, the analysis is performed using the following filter settings. When setting the surface shape correction, use "plane tilt correction." Note that "plane tilt correction" is used when measuring either the non-sputtered area on the surface or side of the sputtering target. <Filter settings> Filter type: Gaussian S-filter: None F-operation: Enabled L-filter: None End effect correction: Checked Note that the surface area is measured using a function called volumetric area measurement under the following conditions. <Surface area measurement conditions> Measurement mode: Convexity Height threshold setting: Set so that all unevenness in the measurement field is included in the measurement. Select the height threshold setting button, which is one of the operation screens of the Keyence VK-X3000, and drag the bar on the displayed screen upwards so that it covers all the spectrum shown in black, to set so that all unevenness in the measurement field is included in the measurement. Ignore minute unevenness: None Ignore minute areas: Enabled Include top and bottom surfaces in surface area calculation: None

[0025] The configuration of the non-sputtering region described above has been described for non-sputtering region 12a of sputtering target 10a shown in FIG. 1(A), but is not limited to this and may also be included in non-sputtering regions 12b and 13b of sputtering target 10b shown in FIG. 1(B), or in non-sputtering regions of sputtering targets according to other embodiments of the present invention.

[0026] <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.

[0027] <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. In the method for manufacturing a sputtering target according to an embodiment of the present invention, first, raw materials for forming a sintered body are prepared. The raw materials for the sintered body may be a powder containing at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, O, Mg, Zn, Ag, Cu, Ni, Ta, Nb, V, W, Mn, Bi, Ge, and Ir, or may be a powder containing an alloy or ceramic containing at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, Mg, Zn, Ag, Cu, Ni, Ta, Nb, V, W, Mn, Bi, Ge, and Ir. Alternatively, the raw materials for the sintered body may be a powder containing an alloy particle phase and a nonmagnetic material. The purity of these raw materials is usually 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 cause problems such as the desired physical properties not being obtained (for example, a decrease in the transmittance of the formed thin film, an increase in resistance, and the generation of particles due to arcing). These raw materials can be appropriately prepared based on the composition and purity of the desired sintered compact.

[0028] Next, the powders of these raw materials are pulverized and mixed. The pulverization and mixing of the powders of the raw materials can be performed using a ball mill using ceramic balls.

[0029] The mixture obtained by mixing and pulverizing as described above is then hot-pressed to obtain a sintered body. Sintering conditions can be appropriately selected depending on the composition of the sintered body.

[0030] The sintered body is then machined on a lathe to obtain a target of a desired shape. The surface roughness after lathe machining is preferably set to 1 μm or less (Ra) so as not to affect laser machining.

[0031] Next, under atmospheric pressure, a surface in which the above-mentioned Spc, Sdr, Sa, Sz, and Sq are controlled can be formed in the non-sputtering region of the sintered body by laser processing. The values ​​of Spc, Sdr, Sa, Sz, and Sq can be appropriately adjusted by the laser irradiation output, the laser light scanning speed, and multiple scanning of the same location. More specifically, by appropriately adjusting each condition in the following laser processing conditions, the Spc, Sdr, Sa, Sz, and Sq of the non-sputtering region of the sputtering target according to an embodiment of the present invention can be controlled to within the desired numerical range.

[0032] In this embodiment, the sintered body is not heated using a separate heating device during the roughening treatment (laser irradiation). This is because the roughening treatment is performed under atmospheric pressure, and heating would facilitate oxidation of the sputtering target. Furthermore, it is not anticipated that any particular treatment will be performed to remove residual stress in the sputtering target before, after, or during the roughening treatment. Furthermore, the back surface of the sputtering target is not roughened. This is because performing the roughening treatment on the back surface could reduce the strength of the sputtering target.

[0033] (Laser Processing Conditions) Laser processing power: 15 to 25 W Scanning speed: 150 to 1000 mm / s Number of scans at the same location: 1 to 10 times Frequency: 140 to 400 kHz Scanning pitch: 0.05 to 0.18 mm Based on the above conditions, laser processing may be performed by first drawing a cross pattern (angle 0°) as "Layer 1," and then drawing a cross pattern (layer 2) without rotation (0° rotation) or rotated by a predetermined angle, overlapping the cross pattern with the laser, thereby drawing a linear pattern at 0° or a predetermined angle. Further, laser processing may be performed a desired number of times. As described above, sputtering targets according to embodiments of the present invention can be manufactured. However, because the above conditions basically depend on the target composition (due to differences in thermal conductivity and melting point), it is necessary to find the conditions through trial and error for the composition.

[0034] In this embodiment, further roughening of the non-sputtered region after roughening treatment is not contemplated. For example, physical roughening methods such as bead blasting or chemical roughening methods such as chemical etching are not contemplated. For example, if the non-sputtered region is further bead blasted after roughening treatment, the blasting media would remain. Note that the non-sputtered region may be roughened by other methods than laser irradiation, as long as the desired surface condition can be achieved. However, roughening the non-sputtered region 12a by laser irradiation can achieve a surface free of ZrO2 and SiC. The presence of ZrO2 and SiC on the surface of the non-sputtered region 12a means, for example, that elements of the blasting media are present on the surface of the non-sputtered region 12a. The absence of ZrO2 and SiC on the surface of the non-sputtered region 12a prevents elements of the blasting media from being mixed into the thin film and suppresses arcing during sputtering. Furthermore, if the composition of the sputtering target does not contain Al2O3, Al2O3 is not present. The presence of Al2O3 on the surface of the non-sputtering region 12a even when the composition of the sputtering target does not contain Al2O3 means, for example, that elements of the blasting media are present on the surface of the non-sputtering region 12a. The absence of Al2O3 on the surface of the non-sputtering region 12a can prevent elements of the blasting media from being mixed into the thin film and can also suppress arcing during sputtering.

[0035] <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.

[0036] A portion of the sputtered particles re-adhere to the non-sputtered region of the sputtering target to form a redeposited film. In the sputtering target according to the embodiment of the present invention, the arithmetic mean curvature Spc of the peaks on the surface of the non-sputtered region is 3200 mm. -1 Because of the above control, the adhesion of the redeposited film formed in the non-sputtered region is improved, and peeling of the redeposited film is effectively suppressed.

[0037] 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.

[0038] Examples 1 to 7 - Manufacturing of Sputtering Targets Sputtering targets according to Examples 1 to 7 were manufactured using the following manufacturing method. First, raw materials for the sintered body were prepared. The raw materials for the sintered body were powders containing Co, Cr, Pt, B, O, Ti, and Si (Examples 1 to 5), powders containing Co, Pt, B, O, Ti, and Si (Example 6), and powders containing Co, Pt, Ru, Ti, O, and Si (Example 7). The purity of each of these raw materials was 3N (99.9% by mass). Next, these raw material powders were pulverized using a ball mill with beads, and the resulting mixture was hot-pressed to obtain a sintered body. Next, the sintered body was machined using a lathe to obtain a disk-shaped target. Next, under atmospheric pressure, a surface with controlled Spc, Sdr, Sa, Sz, and Sq was formed in the non-sputtered region of the sintered body by laser processing. For the laser processing, first, a cross pattern was drawn with a laser (angle 0°) as "Layer 1," and then, as "Layer 2," a cross pattern was drawn with the laser either without rotation (0° rotation) or rotated 45°, overlapping the cross pattern, thereby drawing a linear pattern at 0° or 45° intervals. Note that in Example 4, only Layer 1 was laser processed. The laser processing conditions for Layer 1 and Layer 2 are shown below. Tables 1 and 2 also show the laser processing conditions for each Example.

[0039] (Laser processing conditions for layer 1) Laser processing output: 20 W Scanning speed: 200 to 400 mm / s Number of scans at the same location: 1 Frequency: 140 to 220 kHz Scanning pitch: 0.1 mm

[0040] (Laser processing conditions for layer 2) Laser processing power: 20 W Scanning speed: 200 to 800 mm / s Number of scans at the same location: 1 Frequency: 140 to 220 kHz Scanning pitch: 0.1 to 0.131 mm

[0041] <Comparative Examples 1 to 7> - Manufacturing of Sputtering Targets Sputtering targets according to Comparative Examples 1 to 7 were manufactured using the following manufacturing method. First, raw materials for the sintered body were prepared. The raw materials for the sintered body were powder containing Co, Cr, Si, and O (Comparative Examples 1 to 4), powder containing Co, Fe, B, and N (Comparative Example 5), powder containing Co, Pt, B, O, Ti, and Si (Comparative Example 6), and powder containing Co, Cr, Pt, B, O, Ti, and Si (Comparative Example 7). The purity of each of these raw materials was 3N (99.9% by mass). Next, these raw material powders were pulverized using a media-agitation mill with beads, and the resulting mixture was hot-pressed to obtain a sintered body. Next, the sintered body was machined using a lathe to obtain a disk-shaped target. Next, under atmospheric pressure, a surface with controlled Spc, Sdr, Sa, Sz, and Sq was formed in the non-sputtered region of the sintered body by laser processing. For the laser processing, first, a cross pattern was drawn with a laser (angle 0°) as "Layer 1," and then, as "Layer 2," a cross pattern rotated by 45° or 120° was drawn with the laser, overlapping the cross pattern, thereby drawing a straight line pattern every 45° or 120°. Note that for Comparative Examples 1 and 2, only Layer 1 was laser processed. For Comparative Example 7, only the lathe processing described above was performed, and no laser processing was performed. The laser processing conditions for Layer 1 and Layer 2 are shown below. Tables 1 and 2 also show the laser processing conditions for each Comparative Example. (Laser processing conditions for Layer 1) Laser processing output: 4.8 to 20 W Scanning speed: 100 to 1000 mm / s Number of scans at the same location: 1 to 6 times Frequency: 50 to 140 kHz Scanning pitch: 0.2 mm

[0042] (Laser processing conditions for layer 2) Laser processing power: 4.8 to 20 W Scanning speed: 100 to 500 mm / s Number of scans at the same location: 1 to 3 times Frequency: 50 to 140 kHz Scanning pitch: 0.2 mm

[0043] Optical Microscope Photograph An optical microscope photograph was taken using a laser microscope VK-X3000 of the non-sputtered region of Example 3. The optical microscope photograph (magnification: 360 times) of Example 3 is shown in FIG.

[0044] Spc, Sdr, Sa, Sz, Sq For the sputtering targets of Examples 1 to 7 and Comparative Examples 1 to 7, the arithmetic mean curvature Spc of the peaks of the non-sputtered regions, the developed area ratio Sdr, the surface roughness Sa, the maximum height Sz, and the root mean square height Sq were measured using a laser microscope (Keyence VK-X3000). The measurement procedures were as described above.

[0045] Peel Test A peel test was conducted on Examples 1 to 5 to confirm the adhesion of the redeposited film. The peel test was conducted in accordance with JIS-K5400 (checkerboard tape method). A commercially available lacquer spray was applied to each non-sputtered area and allowed to dry for at least 6 hours. Subsequently, a cutter was used to cut the coating film formed by the application of the lacquer spray, creating 100 1 mm square grids (square grids). Furthermore, cellophane tape was applied to the surface of the cut coating film, and when the cellophane tape was peeled off, the degree of grid peeling was evaluated on a scale of 0 to 10 as specified in JIS-K5400. In all of Examples 1 to 5, each cut was fine and smooth on both sides, and no peeling was observed between the intersections of the cuts and each of the squares. Therefore, a score of 10 was given. A similar test was conducted on Comparative Example 7, and the peeling area was between 35 and 65%, resulting in a score of 2. From these results, it was confirmed that peeling of the redeposition film was successfully suppressed in Examples 1 to 5. As examples of the peel test method, FIG. 3(A) shows a photograph of the appearance of the sample surface after lacquer spray application in Example 3, FIG. 3(B) shows a photograph of the appearance of the sample surface after cutting out a 1 mm square grid in Example 3, and FIG. 3(C) shows a photograph of the appearance of the sample surface after the peel test in Example 3. FIG. 3(D) shows a photograph of the appearance of the sample surface after the peel test in Comparative Example 7. Table 2 shows the evaluation results.

[0046]

[0047]

[0048] <Discussion> In all of the sputtering targets of Examples 1 to 5, the arithmetic mean curvature Spc of the peaks on the surface of the non-sputtering region was 3200 mm -1 As a result, the adhesion of the coating film formed in the non-sputtered region was improved, and peeling of the coating film was effectively suppressed. In addition, in Examples 6 and 7, as in Examples 1 to 5, the arithmetic mean curvature Spc of the peaks on the surface of the non-sputtered region was 3200 mm -1 Therefore, it is considered that peeling of the coating film can be effectively suppressed in the same way. From this result, it is considered that peeling of the redeposited film can be effectively suppressed even during sputtering. In addition, the sputtering target of Comparative Example 7 has an arithmetic mean curvature Spc of the peaks on the surface of the non-sputtered region of 3200 mm -1 In addition, the sputtering targets of Comparative Examples 1 to 6, like Comparative Example 7, all had an arithmetic mean curvature Spc of the peaks on the surface of the non-sputtered region of 3200 mm -1 Therefore, it is considered that large peeling of the coating film was observed in the peel test, similar to Comparative Example 7. From this result, it is considered that the adhesion of the redeposited film formed in the non-sputtered region is reduced, and peeling of the redeposited film during sputtering cannot be effectively suppressed.

[0049] 10a, 10b: sputtering targets; 11a, 11b: sputtering regions; 12a, 12b, 13b: non-sputtering regions

Claims

1. A sputtering target for magnetic materials having a sputtering region and a non-sputtering region, wherein the arithmetic mean curvature Spc of the peaks on the surface of the non-sputtering region is 3200 mm -1 This is the above sputtering target for magnetic material.

2. A sputtering target for magnetic material according to claim 1, wherein the developed surface area ratio Sdr of the non-sputtering region is 4.5 or more.

3. A sputtering target for a magnetic material according to claim 1 or 2, wherein the surface roughness Sa of the non-sputtered region is 10 to 40 μm.

4. A sputtering target for a magnetic material according to claim 1 or 2, wherein the maximum height Sz of the non-sputtering region is 100 to 250 μm.

5. The sputtering target for magnetic material according to claim 1 or 2, wherein the root mean square height Sq of the non-sputtered region is 3 to 45 μm.

6. The sputtering target for magnetic material according to claim 1 or 2, comprising at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, O, Mg, Zn, Ag, Cu, Ni, Ta, Nb, V, W, Mn, Bi, Ge and Ir in its composition.

7. A sputtering target assembly for a magnetic material, comprising: a sputtering target for a magnetic material according to claim 1 or 2; and a backing plate joined to the sputtering target for a magnetic material.

8. A method for manufacturing a sputtering target for a magnetic material having a sputtering region and a non-sputtering region, wherein the non-sputtering region has an arithmetic mean curvature Spc of the peak of 3200 mm -1 A method for producing a sputtering target for a magnetic material, comprising the above-described step of forming a surface.

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