Sputtering targets for magnetic materials and sputtering target assemblies for magnetic materials

Abstract

To provide a sputtering target for a magnetic material that can preferably suppress redeposition film detachment, and to provide a sputtering target assembly for a magnetic material and a method for manufacturing a sputtering target for a magnetic material.SOLUTION: A sputtering target includes a sputter region and a non-sputter region and is used for a magnetic material. In the sputtering target for a magnetic material, the non-sputter region includes: a groove part arrayed into a plurality of lines; a part to be sectioned that is sectioned by a plurality of groove parts; and a swell part provided in a boundary between the groove part and the part to be sectioned.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[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. [Background technology]

[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 are primarily composed of Co or Fe, 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 opposite the sputtering target.

[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 these problems, Patent Document 1 discloses that the area of ​​the sputtering target where the redeposited film is to be formed is roughened by blasting with glass beads. It also discloses that this makes it possible to prevent the redeposited film from peeling off from the roughened surface. Patent Document 2 also discloses that the sputtering target is roughened. Patent Document 2 also discloses that the area 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. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 4-301074 [Patent Document 2] Japanese Patent Application Publication No. 2018-141202 Summary of the Invention [Problem to be solved by the invention]

[0007] Both Patent Documents 1 and 2 only 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. [Means for solving the problem]

[0009] The above 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, The non-sputtering region is A plurality of arranged grooves; a partitioned portion partitioned by the plurality of groove portions; a raised portion provided at the boundary between the groove portion and the partitioned portion; A sputtering target for a magnetic material, comprising: (2) A sputtering target for magnetic materials according to (1), wherein the raised portion is provided so as to extend along the boundary between the groove portion and the partitioned portion, and has a plurality of granular portions in the top region. (3) The sputtering target for a magnetic material according to (2), wherein the granular portion is provided on the surface of the groove portion. (4) The sputtering target for a magnetic material according to (2), wherein the granular portion is provided on the surface of the partitioned portion. (5) A sputtering target for magnetic materials according to any one of (1) to (4), wherein the ratio of the projected area of ​​a predetermined region in the non-sputtering region as the denominator to the surface area of ​​the predetermined region as the numerator is 1.4 or more. (6) The sputtering target for a magnetic material according to any one of (1) to (5), wherein the sputtering target has granular portions having a longest diameter of 5 μm or more in an SEM photograph of the non-sputtered region obtained by observing the non-sputtered region with a scanning electron microscope at a magnification of 100 times. (7) The sputtering target for a magnetic material according to any one of (1) to (6), wherein the non-sputtering region has a surface roughness Sa of 2 to 35 μm. (8) The sputtering target for a magnetic material according to any one of (1) to (7), wherein the non-sputtering region has a maximum height Sz of 20 to 300 μm. (9) The sputtering target for a magnetic material according to any one of (1) to (8), wherein the root mean square height Sq of the non-sputtered region is 2 to 40 μm. (10) The sputtering target for a magnetic material according to any one of (1) to (9), wherein the interval between the plurality of arranged adjacent grooves is 50 to 300 μm. (11) The sputtering target for a magnetic material according to any one of (1) to (10), wherein the groove has a width of 10 to 200 μm. (12) The sputtering target for a magnetic material according to any one of (1) to (11), wherein the partitioned portion is substantially polygonal. (13) The number density of the partitioned portions in the non-sputtering region is 10 to 200 / mm 2 The sputtering target for a magnetic material according to any one of (1) to (12), (14) A sputtering target for a magnetic material according to any one of (1) to (13), which contains Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, and O in its composition. (15) A sputtering target for a magnetic material according to any one of (1) to (14), a backing plate bonded to the sputtering target for magnetic material; 1. A sputtering target assembly for a magnetic material, comprising: (16) A method for manufacturing a sputtering target for a magnetic material having a sputtering region and a non-sputtering region, comprising: In the non-sputtering region, A plurality of arranged grooves; a partitioned portion partitioned by the plurality of groove portions; a raised portion provided at the boundary between the groove portion and the partitioned portion; A method for manufacturing a sputtering target for a magnetic material, comprising the step of forming a [Effects of the Invention]

[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. [Brief explanation of the drawings]

[0011] [Figure 1]1(A) and 1(B) are plan views each showing a schematic diagram of a sputtering target formed in a disk shape. [Figure 2] 2 is a schematic plan view showing an enlarged view of a part of a non-sputtering region formed on the peripheral portion of the surface of the sputtering target shown in FIG. 1(A). [Figure 3] 3 is a cross-sectional view of a non-sputtered region taken along line LL in FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view of a non-sputtered region corresponding to line LL in FIG. 2, according to another embodiment different from that of FIG. 3. FIG. [Figure 5] FIG. 5 is a diagram for explaining the concept of measuring the longest diameter of the granular portion. [Figure 6] 6(A) and (B) are operation screens of the Keyence VK-X3000. [Figure 7] 1 is a SEM photograph of a non-sputtered region of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, embodiments for carrying out 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 targets for magnetic materials> The shape of the sputtering target for a 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 a 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 Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, or O, or may include an alloy containing at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, and Al. The sputtering target may also be made of a material containing an alloy particle phase and a nonmagnetic material. The nonmagnetic 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 sputtering regions and non-sputtering regions of a sputtering target according to an embodiment of the present invention are shown in FIGS. 1A and 1B. FIGS. 1A and 1B are plan views each showing a disk-shaped sputtering target 10a, 10b, respectively. In this embodiment, a right-handed Cartesian coordinate system (X, Y, Z) is used for the following description. In the following description, the direction parallel to the thickness direction of the sputtering target and extending from the rear surface to the front surface is referred to as the positive Z-axis direction, and the direction from the front surface to the rear surface is referred to as the negative Z-axis direction. Two axes perpendicular to the Z-axis and parallel to each other are referred to as the X-axis and Y-axis, respectively. The positive X-axis, negative X-axis, positive Y-axis, and negative Y-axis directions are defined based on the right-handed system. The terms "high position," "low position," and "height difference" may be used to describe the surface condition. A high position refers to a position located relatively on the positive side in the Z-axis direction, and a low position refers to a position located relatively on the negative side in the Z-axis direction. The "height difference" refers to the difference in position between two predetermined positions in the Z-axis direction.

[0017] In the sputtering target 10a shown in FIG. 1(A), 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 area, including the central portion, is a sputtering region 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. In this case, the non-sputtering region on the entire or part of the side surface has the same characteristics as the non-sputtering region described below.

[0018] In the sputtering target 10b shown in FIG. 1(B), 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 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 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 or a portion of the side surface non-sputtering region has the same characteristics as the non-sputtering region described below.

[0019] The non-sputtering region of the sputtering target according to an embodiment of the present invention has a plurality of arranged grooves, a partitioned region partitioned by the plurality of grooves, and a raised portion provided at the boundary between the grooves and the partitioned region. This configuration allows for the formation of somewhat periodic irregularities, and the presence of the raised portion ensures a sufficient surface area. This improves the adhesion of the redeposited film formed in the non-sputtering region, effectively preventing peeling of the redeposited film. As a result, particle contamination during sputtering is suppressed, improving the product yield.

[0020] 2 is a schematic plan view showing an enlarged view of a portion of the non-sputtering region 12a formed on the peripheral portion of the surface of the sputtering target 10a shown in FIG. 1(A). As shown in FIG. 2, the non-sputtering region 12a has a grid pattern in which multiple grooves 30 are arranged vertically and horizontally and intersect. The partitioned portion 31 is partitioned into a rectangular shape by the grooves 30. In addition, a raised portion 32 is provided at the boundary between the grooves 30 and the partitioned portion 31. While it is sufficient for the raised portion 32 to be provided at a portion of the boundary between the grooves 30 and the partitioned portion 31, it is more preferable for the raised portion 32 to be provided at the entire boundary in order to further increase the roughness of the non-sputtering region 12a and improve the adhesion of the redeposited film.

[0021] In FIG. 2, non-sputtering region 12a has multiple grooves 30 arranged vertically and horizontally to form a grid pattern. However, the configuration pattern of non-sputtering region 12a is not limited to this and may be a pattern consisting of other polygons. For example, non-sputtering region 12a may have a pattern in which three grooves 30 define triangular partitioned regions 31, or a pattern in which five or more grooves 30 define polygonal partitioned regions 31 having pentagonal or higher polygonal shapes. In particular, eight grooves 30 may define octagonal partitioned regions 31. Furthermore, the multiple partitioned regions 31 defined by grooves 30 may have the same size or different sizes. While non-sputtering region 12a may have a polygonal configuration as described above, this polygon may have a rounded shape (also referred to as a substantially polygonal shape) with at least one corner crushed. That is, the partitioned portion 31 may be substantially polygonal when viewed along the normal direction of the non-sputtering region 12a.

[0022] The non-sputtered region 12a may have the above-mentioned polygonal pattern in a portion thereof, but it is preferable that the entire non-sputtered region 12a have the above-mentioned polygonal pattern in order to further increase the roughness of the non-sputtered region 12a and improve the adhesion of the redeposition film.

[0023] FIG. 3 shows a cross-sectional schematic diagram of the non-sputtering region 12a taken along line LL in FIG. 2. The grooves 30 are arranged at a lower position than the partitioned region 31. The raised portion 32 at the boundary between the grooves 30 and the partitioned region 31 extends along the boundary between the grooves 30 and the partitioned region 31 and has a plurality of granular portions 34 at its apex region. In other words, in the embodiment shown in FIG. 3, the raised portion 32 in the non-sputtering region 12a has a plurality of granular portions 34 at its apex region that form the boundary between the grooves 30 and the partitioned region 31. In this case, the plurality of granular portions 34 may be arranged in a single row to form the boundary between the grooves 30 and the partitioned region 31, or in two or more rows to form the boundary between the grooves 30 and the partitioned region 31, or the plurality of granular portions 34 may be arranged randomly to form the boundary between the grooves 30 and the partitioned region 31. The multiple granular portions 34 may be of approximately the same size as each other, or may be of different sizes. By having multiple granular portions 34 in the top region of the raised portion 32, the surface area is further increased. Furthermore, gaps are formed between the granular portions 34 and the partitioned portion 31. When the redeposited film enters these gaps, the granular portions 34 function as catches, making it possible to more effectively prevent the redeposited film from peeling off.

[0024] The raised portion 32 has a base portion 33 configured to extend to the top region with the surface position of the partitioned portion 31 as the bottom position and support the granular portion 34. The shape of the base portion 33 is not particularly limited, and the cross section may be polygonal such as rectangular, circular, elliptical, or the like. Furthermore, similar to the above-mentioned multiple granular portions 34, multiple base portions 33 may be connected together to form the boundary between the groove portion 30 and the partitioned portion 31. Furthermore, the raised portion 32 may be composed only of the granular portions 34 without the base portion 33.

[0025] FIG. 4 shows a cross-sectional schematic diagram of the non-sputtering region 12a corresponding to line LL in FIG. 2, which relates to an embodiment different from that shown in FIG. 3. In the embodiment shown in FIG. 4, granular portions 35 are provided on the surface of the grooves 30. This configuration further increases the roughness of the non-sputtering region 12a, thereby improving the adhesion of the redeposited film. Furthermore, since the surface area of ​​the non-sputtering region 12a can be increased without forming the grooves 30 deeper, the adhesion of the redeposited film can be improved while maintaining the strength of the sputtering target compared to when the grooves 30 are formed deeper. Multiple granular portions 35 may be provided on the surface of the grooves 30, spaced apart from each other, or may be provided in close contact with each other. In an SEM photograph of the non-sputtering region 12a obtained by observing the non-sputtering region 12a with a scanning electron microscope (S-3700N, manufactured by Hitachi High-Technologies Corporation) at 100x magnification, it is preferable that granular portions with a longest diameter of 5 μm or more are present. The longest diameter can be defined as the length of the longest line passing through the granular portion 35 when a line is drawn through the granular portion 35 on the SEM photograph. It is assumed that this SEM photograph is obtained by observing the non-sputtered region 12a on the surface of the sputtering target from the relatively positive Z-axis direction. When obtaining an SEM photograph of the non-sputtered region on the side of the sputtering target, the non-sputtered region on the side is observed from a position away from the Z-axis toward the Z-axis. When measuring with a scanning electron microscope, the accelerating voltage, current value (irradiation current value), brightness, and contrast can be adjusted to ensure a clear image. This configuration increases the contact area between the granular portion and the base, thereby more firmly connecting the granular portion to the base and reducing the likelihood of the granular portion peeling off from the base. Therefore, the redeposited film has a larger contact area with the non-sputtered region. Therefore, adhesion between the redeposited film and the granular portions is ensured, and the redeposited film can be more effectively held on the surface of the sputtering target. It is more preferable that granular portions having a longest diameter of 10 μm or more are present in an SEM photograph of the non-sputtered region 12 a obtained by observing the non-sputtered region 12 a with a scanning electron microscope at a magnification of 100 times.When the granular portions 35 are independent but overlap and appear as double circles, the longest diameter is measured at the outermost outline in the SEM photograph. When the granular portions 35 are in contact with each other, the longest diameter is measured for each of them after separating them at the boundary. The multiple granular portions 35 may be of similar size or may be of different sizes. The granular portions 35 may be formed separately from the groove portions 30, but from the viewpoint of strength and manufacturing efficiency, it is more preferable that they be formed integrally with the groove portions 30. When observing an SEM photograph of the non-sputtered region 12a, if multiple granular portions 34 are independent but overlap each other, and multiple outlines are visible, the longest diameter is measured at the outermost outline of these. Also, if multiple granular portions 35 are in contact with each other, they are separated at their boundaries and then considered to be independent granular portions, and the longest diameter is measured accordingly. The concept of measuring the longest diameter of the granular portion 34 will be explained in detail below with reference to Figures 5(A) to 5(C). Figure 5(A) is an example of an SEM photograph of the non-sputtered region 12a. Figure 5(B) is a schematic diagram illustrating the concept of measuring the longest diameter of the granular portion 34 in part F1 of the SEM photograph of Figure 5(A). In part F1 of Figure 5(A), as shown in Figure 5(B), it appears that there is an outer contour 341 and an inner contour 342 for each granular portion 34. Alternatively, it may appear that multiple granular portions 34 overlap. In this case, it is assumed that there is one granular portion 34, and the contour 341 is used as the contour of that granular portion 34, and the longest diameter is measured based on the contour 341. In part F2 of the SEM photograph of Figure 5(A), it appears that there are two granular portions 34 that are in contact with each other, as shown in Figure 5(C). Furthermore, it appears that there is a boundary line at the contact point between the two granular portions 34. The dashed lines in Figure 5(C) indicate the boundary lines between the granular portions 34. In this case, the granular portions 34 are separated by the boundary line and considered to be two independent granular portions 34, and the longest diameter of each granular portion 34 is measured. Note that, although not shown, the same applies when there are three granular portions 34 that are in contact with each other; they are separated by each boundary line and considered to be three independent granular portions 34, and the longest diameter of each granular portion 34 is measured.

[0026] In the embodiment shown in FIG. 4 , granular portions 36 are provided on the surface of the partitioned portion 31. In this manner, the granular portions 36 may be provided on the surface of the partitioned portion 31. This configuration further increases the roughness of the non-sputtered region 12a and the surface area of ​​the non-sputtered region 12a, thereby further improving the adhesion of the redeposited film. Multiple granular portions 36 may be provided on the surface of the partitioned portion 31, spaced apart from one another, or may be provided in close contact with one another. The multiple granular portions 36 may have approximately the same size as one another, or may have different sizes from one another. The granular portions 36 may be formed separately from the partitioned portion 31, but are preferably formed integrally with the partitioned portion 31 from the standpoints of strength and manufacturing efficiency.

[0027] The number density of the partitioned portions 31 in the non-sputtering region 12a is 10 to 200 pieces / mm 2 It is preferable that the number density of the partitioned portions 31 in the non-sputtering region 12a is 10 / mm 2 If the number density of the partitioned portions 31 in the non-sputtered region 12a is set to 200 / mm, the ratio of the protruding portions 32 in the non-sputtered region 12a can be increased, and the surface area of ​​the non-sputtered region 12a in contact with the redeposited film can be increased, thereby improving the adhesion of the redeposited film. 2 If the number density of the partitioned portions 31 in the non-sputtering region 12a is increased beyond 200 / mm, the partitioned portions 31 become too small, and as a result, the partitioned portions 31 cannot be formed. 2 By doing so, the partitioned portions 31 can be reliably formed in the non-sputtering region 12a, and periodic unevenness can be formed to some extent. The number density of the partitioned portions 31 in the non-sputtering region 12a is 20 to 100 pieces / mm 2 It is more preferable that:

[0028] In the multiple arranged grooves 30, the grooves 30 preferably extend substantially parallel to one another, and the spacing between adjacent grooves 30 is preferably 50 to 300 μm. If the spacing between adjacent grooves 30 is 50 μm or more, a sufficiently large protrusion 32 can be formed. If the spacing between adjacent grooves 30 exceeds 300 μm, the ratio of the protrusion 32 in the non-sputtered region 12a becomes too small, and the surface area of ​​the non-sputtered region cannot be secured at a certain level, which may result in a decrease in the adhesion of the redeposited film. In the multiple arranged grooves 30, the spacing between adjacent grooves 30 is more preferably 100 to 200 μm.

[0029] The width of the grooves 30 is preferably 10 to 200 μm. If the width of the grooves 30 is less than 10 μm, the redeposited film may not easily enter the grooves 30, making it difficult to secure the redeposited film. If the width of the grooves 30 exceeds 200 μm, the ratio of the protruding portions 32 in the non-sputtered regions 12 a may become too small, reducing the adhesion of the redeposited film. This also results in a relative decrease in the number of grooves per unit area, i.e., the density of the grooves. Because the grooves serve to retain the redeposited film, a decrease in the density of the grooves may reduce the adhesion of the redeposited film. The width of the grooves 30 is more preferably 30 to 100 μm in order to secure the redeposited film and improve adhesion with the redeposited film.

[0030] In the non-sputtered region 12a, the ratio (hereinafter referred to as the "surface area ratio") of the projected area of ​​a predetermined region in the non-sputtered region 12a as the denominator to the surface area S of the predetermined region as the numerator is preferably 1.4 or greater. Here, the "projected area of ​​a predetermined region in the non-sputtered region 12a" refers to the two-dimensional surface area of ​​the predetermined region, and the "surface area S of the predetermined region" refers to the three-dimensional surface area. In other words, the surface area ratio refers to the ratio of the surface area S (three-dimensional surface area) to the projected area (two-dimensional surface area) of the predetermined region in the non-sputtered region 12a. In the non-sputtered region 12a, a surface area ratio of 1.4 or greater increases the roughness of the non-sputtered region 12a, thereby improving the adhesion of the redeposited film. The projected area of ​​the predetermined region is determined by a specified range designation operation during measurement with a laser microscope and is output along with the measurement data. In the non-sputtered region 12a, the surface area ratio is more preferably 1.6 or greater. In the non-sputtering region 12a, the upper limit of the surface area ratio is not particularly limited, but may be 3.0 or less, or may be 2.5 or less.

[0031] The surface roughness Sa of the non-sputtering region 12a is preferably 2 to 35 μm. When the surface roughness Sa of the non-sputtering region 12a is 2 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 35 μm, the number of protruding portions, which are portions that protrude away from the surface of the sputtering target, becomes too large. The increased number of protruding portions may induce arcing. The surface roughness Sa of the non-sputtering region 12a is more preferably 4 to 30 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 roughness Ra of the surface is evaluated using a line, the surface roughness Sa is evaluated using a surface. The measurement results for the average roughness Ra vary depending on the portion selected for measurement. For example, if the measurement target is set along the groove portion 30 and Ra is measured, Ra will be smaller than if the measurement target is set across the partitioned portion. Therefore, by using the surface roughness Sa, the variation in Sa depending on the setting position of the measurement target is reduced, 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.

[0032] The maximum height Sz of the non-sputtered region 12a is preferably 20 to 300 μm. If the maximum height Sz of the non-sputtered region 12a is 20 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 easily secured at high and low positions of 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 300 μm, this means that there are too many protruding portions. Therefore, the tops of the protruding portions may peel off, resulting in a small maximum height Sz. The maximum height Sz of the non-sputtered region 12a is more preferably 25 to 250 μm. The maximum height Sz of the non-sputtered region 12a can be measured using a laser microscope in accordance with ISO-25178.

[0033] The root-mean-square height Sq of the non-sputtered region 12a is preferably 2 to 40 μm. If the root-mean-square height Sq of the non-sputtered region 12a is 2 μm or more, high and low portions from the average surface are dispersed, resulting in a large difference in elevation within the non-sputtered region 12a. 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 within the non-sputtered region 12a. This makes it difficult for the redeposited film to peel off from the non-sputtered region. If the root-mean-square height Sq of the non-sputtered region 12a exceeds 40 μm, this indicates a 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 5 to 36 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.

[0034] The above surface areas S, Sa, Sz, and Sq can be measured using a laser microscope (Keyence VK-X3000) as follows: In the case of the VK-X3000, a 10x objective lens, 1.5x digital zoom, and 24x screen magnification are used to obtain a 360x (10x x 1.5x x 24x) image. The analysis software used was the multi-file analysis application ver. 3.3.1.85 included with the VK-X3000. First, select surface roughness measurement as the measurement mode, and select the desired roughness parameters and region area. When selecting the region area, specify a range of (896 μm x 672 μm) from the acquired image (360x image). Note that the region area mentioned above is determined by performing this range specification operation on the laser microscope. Next, the analysis is performed with the filter settings set to the following conditions. When setting the surface shape correction, use "plane tilt correction." Note that "plane tilt correction" is used whether the non-sputtered region of the surface or side of the sputtering target is the measurement target. <Filter settings> Filter type: Gaussian S-filter: None F-Operation: Enabled L-filter: None End effect correction: Check The surface area is measured under the following conditions using a function called volume area measurement. <Surface area measurement conditions> Measurement mode: Convex part Setting the height threshold: Set this so that all irregularities in the measurement field are included in the measurement. Selecting the height threshold setting button in Figure 6(A), one of the operation screens of the Keyence VK-X3000, displays the screen shown in Figure 6(B). By dragging the bar on this screen upwards so that it covers all the spectra shown in black, it is possible to set it so that all irregularities in the measurement field are included in the measurement. Ignore small irregularities: None (Do not check the "Ignore small irregularities" checkbox in Figure 6(A)) Ignore small areas: Enable (check the "Ignore small areas" checkbox in Figure 6(A)) Include top and bottom surfaces in surface area calculation: No (Do not check the "Include top and bottom surfaces in surface area calculation" checkbox in Figure 6(A)) The surface area ratio (S / A) can be calculated by dividing the measured surface area S by the area A (corresponding to the "projected area of ​​a specified area"), which is determined by the range specification operation after the image acquisition described above and output together with the measurement data.

[0035] The configuration of the non-sputtering region described above has been described for non-sputtering region 12a of sputtering target 10a shown in Figure 1(A), but is not limited to this and may also be present in non-sputtering regions 12b, 13b of sputtering target 10b shown in Figure 1(B), or in non-sputtering regions of sputtering targets according to other embodiments of the present invention.

[0036] <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). The material of the backing plate preferably has high thermal conductivity, and from this perspective, Cu is suitable.

[0037] <Method for manufacturing sputtering targets> 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 powders containing Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, and O, or powders containing an alloy or ceramic containing at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, and O. The raw materials for the sintered body may also be powders containing an alloy particle phase and a nonmagnetic material. 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. Purity levels lower than 2N result in the sintered body containing a large number of impurities, which can lead to problems such as an inability to obtain the desired physical properties (e.g., reduced transmittance of the formed thin film, increased resistance, and particle generation due to arcing). These raw materials can be appropriately prepared based on the desired composition and purity of the sintered body.

[0038] Next, the raw material powders are pulverized and mixed. The pulverization and mixing of the raw material powders can be performed using a ball mill using ceramic balls.

[0039] 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.

[0040] The sintered body is then machined on a lathe to obtain a target of the desired shape. The surface roughness after lathe machining is preferably set to 1 μm or less, Ra, so as not to affect laser machining.

[0041] Next, under atmospheric pressure, laser processing is performed on the non-sputtered region of the sintered body to form multiple arranged grooves, partitioned regions defined by the multiple grooves, and raised regions at the boundaries between the grooves and the partitioned regions. Based on the desired configuration pattern of the non-sputtered region, multiple grooves are formed and arranged in the non-sputtered region by scanning and irradiating the laser beam. By forming the grooves in a crossing pattern vertically and horizontally, rectangular partitioned regions are created. Furthermore, by intersecting three grooves to define a partitioned region, triangular partitioned regions are created. In this way, by appropriately patterning the grooves by scanning and irradiating the laser beam, the desired configuration pattern can be formed in the non-sputtered region. Furthermore, depending on the output of the laser irradiation, raised regions can be created at the boundaries between the grooves and the partitioned regions.

[0042] Furthermore, the shape and size of the above-mentioned raised portion, the width of the groove portion, the shape and size of the granular portion of the groove portion, and the shape and size of the partitioned portion can be appropriately adjusted by the output of the laser irradiation, the scanning speed of the laser light, multiple scanning of the same location, etc. More specifically, by appropriately adjusting each condition in the following laser processing conditions, it is possible to control the multiple arranged groove portions in the non-sputtering region of the sputtering target according to an embodiment of the present invention, the partitioned portion partitioned by the multiple groove portions, and the raised portion at the boundary between the groove portion and the partitioned portion to a desired configuration.

[0043] 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.

[0044] (Laser processing conditions) Laser processing power: 3~25W Scanning speed: 100~2000mm / s Scanning the same spot: 1 to 10 times Frequency: 40-200kHz Scanning pitch: 100~400μm In this manner, the sputtering target according to the embodiment of the present invention can be manufactured. However, since the above conditions basically depend on the target composition (because the thermal conductivity and melting point are different), it is necessary to find the conditions by trial and error for the composition.

[0045] In this embodiment, further roughening of the non-sputtered region after roughening treatment is not anticipated. For example, physical roughening methods such as bead blasting or chemical roughening methods such as chemical etching are not anticipated. 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 besides 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 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 non-sputtering region 12a. The absence of Al2O3 on the surface of 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.

[0046] <Film formation method using sputtering targets> The sputtering target according to the embodiment of the present invention can be used to form a thin film that mainly constitutes a magnetic recording medium. Specifically, a sputtering device is used to sputter the surface of the sputtering target with accelerated argon ions, releasing particles (sputtered particles) from the sputtering target, and depositing the sputtered particles on the surface of a substrate previously positioned opposite the sputtering target, thereby forming a thin film on the surface of the substrate. Sputtering conditions can be appropriately set depending on the desired film thickness, composition, etc.

[0047] A portion of the sputtered particles redeposits on the non-sputtering region of the sputtering target to form a redeposited film. In the sputtering target according to the embodiment of the present invention, the non-sputtering region has a plurality of arranged grooves, a partitioned portion partitioned by the plurality of grooves, and a raised portion at the boundary between the grooves and the partitioned portion, as described above, so that the adhesion of the redeposited film formed on the non-sputtering region is improved and peeling of the redeposited film is effectively suppressed. [Example]

[0048] 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.

[0049] <Examples 1 to 6> · Sputtering target manufacturing The sputtering targets according to Examples 1 to 6 were produced by the following production method. First, raw materials for the sintered body were prepared. The raw materials for the sintered body were powder containing Co, Cr, and Si (Examples 1 to 4), powder containing Co, Fe, B, and N (Example 5), and powder containing Co, Pt, B, Ti, and Si (Example 6). The purity of these raw materials was 3N (99.9% by mass). Next, the powders of these raw materials were pulverized in a media agitation mill using beads, and the mixture obtained by mixing 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 plurality of arranged grooves, a partitioned area partitioned by the plurality of grooves, and a raised area at the boundary between the grooves and the partitioned area were formed in the non-sputtered area of ​​the sintered body by laser processing. Based on the desired configuration pattern of the non-sputtered area, a plurality of grooves were formed and arranged in the non-sputtered area by scanning and irradiating with laser light. In Examples 1 and 2, a pattern (90° grating pattern) in which multiple grooves intersect with each other at 90° to form a grating was formed in the non-sputtering region by laser processing. For example, a 90° grating pattern can be formed by forming multiple grooves along the X-axis and then forming multiple grooves along the Y-axis. In Example 3, a pattern (60° grating pattern) in which multiple grooves intersect with each other at 60° to form a grating was formed in the non-sputtering region. For example, a 60° grating pattern was formed by forming multiple grooves along the X-axis, then forming multiple grooves along a direction tilted 60° from the X-axis, and then forming multiple grooves along a direction tilted further 60° (120° from the X-axis). In Examples 4 to 6, a pattern (45° grating pattern) in which multiple grooves intersect with each other at 45° to form a grating was formed in the non-sputtering region. For example, a 45° grating pattern is formed by forming multiple grooves along the X axis, forming multiple grooves along the Y axis, forming multiple grooves along a direction tilted 45° from the X axis, and then forming multiple grooves along a direction tilted 45° from the Y axis. The laser processing conditions at this time are shown below: Table 1 also shows the laser processing conditions for each example. (Laser processing conditions) Laser processing power: 4.8~20W Scanning speed: 100~1000mm / s Number of scans of the same area: 1 to 6 times Frequency: 50-140kHz Scanning pitch: 200μm

[0050] SEM photographs SEM photographs were taken of the non-sputtered regions of Examples 1 to 6. Fig. 7 shows an SEM photograph (magnification: 100x) of Example 1. When taking the SEM photograph of Fig. 7, the acceleration voltage was set to 15 kV and the current value (irradiation current value) was set to 84000 nA. Note that, according to Fig. 7, in Example 1, the number density was 25 particles / mm 2 This can be estimated as a rough value. Groove areas, raised areas, partitioned areas, granular areas The SEM photographs obtained confirmed that grooves, protruding portions, and partitioned portions were formed in the non-sputtered regions of Examples 1 to 6. Granular portions were also confirmed to have formed at the tops of the protruding portions. Furthermore, it was confirmed that granular portions also formed in some of the partitioned portions and some of the grooves. It can also be seen that the longest diameter of the granular portions indicated by the arrows in Figure 7 is 5 μm or more.

[0051] ·Surface area S, Sa, Sz, Sq The surface area S, surface roughness Sa, maximum height Sz, and root mean square height Sq of the non-sputtered region were measured using a laser microscope (Keyence VK-X3000) according to the above-mentioned procedure.

[0052] Projected area of ​​a given area in the non-sputtered region, surface area S In the non-sputtering region, the ratio (S / A) was calculated by using the projected area of ​​a specified region in the non-sputtering region relative to a plane perpendicular to the thickness direction of the sputtering target (the region area A determined by a specified range designation operation during laser microscope measurement and output together with the measurement data) as the denominator and the surface area of ​​the specified region (the surface area S of the specified region) as the numerator.

[0053] Groove width Measurements were taken from 3D images taken with a laser microscope. Note that a 3D image can also be obtained when using a laser microscope (VK-X3000) with a 10x objective lens, 1.5x digital zoom, and 24x screen magnification to obtain a 360x (10x x 1.5x x 24x) image. Based on the 3D images, the approximate values ​​of the number density in Examples 1 to 6 were 25 particles / mm2 , 25 pieces / mm 2 , 50 pieces / mm 2 , 60 pieces / mm 2 , 80 pieces / mm 2 , 80 pieces / mm 2 was required.

[0054] [Table 1]

[0055] <Consideration> The sputtering targets of Examples 1 to 6 all had grooves in which a plurality of non-sputtering regions were arranged, partitioned regions partitioned by the plurality of grooves, and raised portions provided at the boundaries between the grooves and the partitioned regions. This allows for the formation of somewhat periodic irregularities, and the presence of raised portions ensures a sufficient surface area, which is thought to improve the adhesion of the redeposited film formed in the non-sputtering regions and effectively suppress peeling of the redeposited film. [Explanation of symbols]

[0056] 10a, 10b Sputtering target 11a, 11b Sputtering area 12a, 12b, 13b Non-sputtered area 30 Groove 31 Partitioned area 32 Prominent section 33 Base 34, 35, 36 Granular part 341, 342 Contour

Claims

1. A sputtering target for magnetic materials having a sputtering region and a non-sputtering region, The non-sputtering region is A plurality of arranged groove portions; a partitioned portion partitioned by the plurality of groove portions; a raised portion extending along the boundary between the groove portion and the partitioned portion and having a plurality of granular portions in a top region; A sputtering target for a magnetic material, comprising:

2. The sputtering target for a magnetic material according to claim 1 , wherein the granular portion is provided on the surface of the groove portion.

3. The sputtering target for a magnetic material according to claim 1 , wherein the granular portion is provided on a surface of the partitioned portion.

4. 4. The sputtering target for a magnetic material according to claim 1, wherein a ratio of a projected area of ​​a predetermined region in the non-sputtering region as a denominator to a surface area of ​​the predetermined region as a numerator is 1.4 or more.

5. 4. The sputtering target for a magnetic material according to claim 1, wherein the target has granular portions having a longest diameter of 5 μm or more in an SEM photograph of the non-sputtered region obtained by observing the non-sputtered region with a scanning electron microscope at a magnification of 100 times.

6. 4. The sputtering target for a magnetic material according to claim 1, wherein the non-sputtering region has a surface roughness Sa of 2 to 35 μm.

7. 4. The sputtering target for a magnetic material according to claim 1, wherein the non-sputtering region has a maximum height Sz of 20 to 300 μm.

8. 4. The sputtering target for a magnetic material according to claim 1, wherein the root mean square height Sq of the non-sputtered region is 2 to 40 μm.

9. 4. The sputtering target for a magnetic material according to claim 1, wherein the distance between the plurality of arranged adjacent grooves is 50 to 300 μm.

10. 4. The sputtering target for a magnetic material according to claim 1, wherein the groove has a width of 10 to 200 μm.

11. The sputtering target for a magnetic material according to claim 1 , wherein the partitioned portion is substantially polygonal.

12. The number density of the partitioned portions in the non-sputtering region is 10 to 200 pieces / mm 2 The sputtering target for a magnetic material according to claim 1 , wherein

13. 4. The sputtering target for a magnetic material according to claim 1, which has a composition containing at least one of Co, Pt, Fe, Ru, Cr, Ti, Si, Zr, B, C, N, Al, and O.

14. The sputtering target for a magnetic material according to any one of claims 1 to 3, a backing plate bonded to the sputtering target for magnetic material; 1. A sputtering target assembly for a magnetic material, comprising:

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