JP4673779B2 - Magnetic recording medium manufacturing method and film forming apparatus - Google Patents

Description

  The present invention relates to a method for manufacturing a magnetic recording medium and a film forming apparatus. In particular, the present invention relates to a method for manufacturing a magnetic recording medium mounted on a perpendicular magnetic recording type hard disk drive and a film forming apparatus.

  A magnetic recording medium mounted on a hard disk drive is manufactured by forming a laminated film on a substrate (disk substrate). This laminated film is formed by, for example, a sputtering method or a CVD method after a substrate mounted on a substrate adapter is placed in a film formation chamber and evacuated.

  Each layer in the laminated film of the magnetic recording medium is formed, for example, by repeatedly transporting the substrate to a plurality of film forming chambers. Further, at least a part of the laminated film is formed by a single-wafer type film forming apparatus, for example, by a magnetron sputtering method. For example, the single-wafer type film forming apparatus forms each layer on each of the substrates installed in front of the disk-shaped target.

  In the magnetron sputtering method, plasma generation efficiency is increased by a leakage magnetic field from an electromagnet or permanent magnet installed on the back side of a target, the film formation rate is increased, and mass productivity is improved. In addition, the current flowing through the electromagnet or the magnet is rotated in a plane parallel to the target, and the leakage magnetic field on the target surface is moved with time, so that the erosion part of the target surface is made uniform, and the use efficiency of the target is improved. It is increasing. A film forming method using a magnetron sputtering method is disclosed in Patent Documents 1 and 2, for example. As a generation source of the leakage magnetic field, it is more common to use a permanent magnet.

  In recent years, a perpendicular magnetic recording system has been researched and developed as a next-generation high-density recording system. As a magnetic recording medium used in the perpendicular magnetic recording system, use of a perpendicular double-layer medium in which a soft magnetic layer is formed under a perpendicular magnetic recording layer has been studied (see, for example, Patent Documents 3, 4, and 5). .) In the perpendicular double-layer medium, the writing ability of the head can be improved by causing the soft magnetic layer to function as a part of the head.

In such a perpendicular magnetic recording system, there is a problem of reducing noise caused by the soft magnetic layer. Conventionally, the configuration in which the easy magnetization axis of the soft magnetic layer is aligned radially from the center of the substrate and the hard magnetization axis is aligned in the circumferential direction is a desirable configuration that does not generate spike noise caused by the domain wall of the soft magnetic layer. It has been known. For example, the easy axis of magnetization of the soft magnetic layer is aligned in the radial direction of the substrate using a leakage magnetic field during film formation by magnetron sputtering.
JP 63-100180 A Japanese Patent No. 3116279 JP 2002-358618 A JP 2003-187413 A JP 2004-118894 A

  In recent years, with the miniaturization of hard disk drives, a small-diameter substrate of about 1 inch or the like is sometimes used as a substrate on which a laminated film is formed. Such film formation on a small-diameter substrate may be performed with a plurality of small-diameter substrates attached to one substrate adapter, for example, for the purpose of improving mass productivity. However, when a soft magnetic layer is simultaneously formed on a plurality of small-diameter substrates by magnetron sputtering, it is difficult to align the easy magnetization axes of the substrates in the respective substrate radial directions.

  7 and 8 are diagrams for explaining this problem. FIG. 7 illustrates an example of a configuration of a film formation apparatus 800 that performs film formation on a plurality of substrates simultaneously. FIG. 7A is a cross-sectional view of the film forming apparatus 800. The film forming apparatus 800 is a DC magnetron sputtering apparatus, and includes a substrate adapter 802, a target 804, and a magnet unit 806.

  The substrate adapter 802 has a plurality of through-hole-shaped substrate accommodating portions, and accommodates each substrate 812 in each substrate accommodating portion. Accordingly, the substrate adapter 802 holds the plurality of substrates 812 side by side in a state where the film formation surface of each substrate 812 faces the target 804. In this state, the film forming apparatus 800 forms a soft magnetic layer or the like on the substrate 812, for example. The target 804 supplies a film material of a film formed on the substrate 812. The magnet unit 806 is a source for generating a leakage magnetic field necessary for the DC magnetron sputtering method.

  FIG. 7B is a plan view showing the magnet unit 806. The magnet unit 806 includes a magnetic field generation unit 810 and a stage 808. The magnetic field generation unit 810 is a magnet array rotatably held on the stage 808, and includes permanent magnets 908 and 910 that are disposed asymmetrically with respect to the rotation center. The permanent magnet 908 is provided in the vicinity of the center of the magnetic field generation unit 810 with the N pole facing the target 804, for example. The permanent magnet 910 faces in the opposite direction to the permanent magnet 908, and is provided so as to surround the permanent magnet 908 with the south pole facing the target 804, for example.

  The stage 808 is a driving device for rotationally driving the magnetic field generation unit 810, and rotates the magnetic field generation unit 810 with respect to a predetermined rotation axis. In accordance with this rotation, the leakage magnetic field changes over time in a range indicated by an arrow 912 in FIG. The stage 808 rotates the magnetic field generator 810 in the direction indicated by the arrow 914 in FIG. 7B, for example.

  Here, the same or similar configuration as the magnetic field generation unit 810 and the stage 808 is also used in a single-wafer type film forming apparatus that forms a film on each substrate. In a single wafer deposition apparatus, a deposition target substrate is held with its center aligned with the rotation center of a stage 808. Accordingly, the center of the substrate also overlaps with the rotation center of the magnetic field generator 806 held on the stage 808. Therefore, when a soft magnetic layer is formed by a single-wafer type film forming apparatus, by rotating the magnetic field generator 810, the easy magnetic axis of the soft magnetic layer is radiused from the center of the substrate by utilizing a leakage magnetic field. It was possible to align the direction radial.

  However, when film formation is performed simultaneously on a plurality of substrates, it is impossible to make the centers of all the substrates coincide with the center of the magnetic field generation unit 810. Therefore, it is impossible to align the easy axis of magnetization of the soft magnetic layer radially from the center of the substrate by using the leakage magnetic field generated by the magnetic field generator 810.

  FIG. 8 shows the direction in which the easy magnetization axis of the soft magnetic layer is controlled in each substrate 812. When the soft magnetic layer is formed on the substrate 812, the easy axis of magnetization of the soft magnetic layer is determined by the arrangement of the permanent magnets 908 and 910 described with reference to FIG. 7B and the rotational motion of the magnetic field generation unit 810. As indicated by the arrows inside, the board adapters 802 are aligned in the radial direction. In this case, in each substrate 812, the easy axis of magnetization crosses the surface of the substrate 812. Therefore, a region where easy axes of magnetization are aligned in the circumferential direction of the substrate 812 is created, and a problem arises that spike noise is generated due to a domain wall surrounding this region.

Here, in order to suppress noise caused by the soft magnetic layer, for example, the following method may be used.
Method (1): A method in which the substrate 812 whose center is aligned with the target is formed for each one without using the substrate adapter 802 that holds the plurality of substrates 812.
Method (2): A method of adding a step of aligning the easy magnetization axis in the radial direction after forming the soft magnetic layer. In this step, for example, the substrate 812 is heated while applying external magnetization that is point-symmetric with respect to the center of the substrate 812. The heating magnetic field application process is performed in the film forming apparatus 800 while the substrate 812 is held by the substrate adapter 802.
Method (3): A method of removing each substrate 812 from the substrate adapter 802 and performing the heating magnetic field application process similar to the method (2). In this case, the substrate adapter 802 is once taken out from the film forming apparatus 800 to the atmosphere after the soft magnetic layer is formed. Then, after the heating magnetic field application process is performed on the substrate 812 removed from the substrate adapter 802, the substrate 812 is mounted on the substrate adapter 802, and the process proceeds to the film forming process of the second half perpendicular magnetic recording layer and the like.

  However, in the case of the method (1), there is a problem that mass productivity is significantly impaired due to a decrease in throughput of the film forming process. Further, in the case of the methods (2) and (3), the addition of the step of aligning the easy axis of magnetization in the radial direction also increases the total time required for forming the soft magnetic layer. However, the mass productivity is further reduced. Therefore, in the case of the methods (2) and (3), the effect of increasing the mass productivity by attaching the plurality of substrates 812 to the substrate adapter 802 is completely lost.

  Thus, conventionally, it has been difficult to achieve both reduction in noise caused by the soft magnetic layer and high mass productivity. Accordingly, an object of the present invention is to provide a method for manufacturing a magnetic recording medium and a film forming apparatus that can solve the above-described problems.

  The inventor of the present application has intensively studied to solve the above problems. Then, a magnet array of magnetron cathodes used in the magnetron sputtering method was individually provided for each substrate, and it was studied to form a soft magnetic layer.

  However, when this method is used for a small-diameter substrate of, for example, about 1 inch, a small magnet arrangement is required according to the size of each substrate. As a result of intensive studies by the present inventors, it has been found that when such a small magnet arrangement is used, the strength of the magnetic field for generating magnetron discharge (sputtering discharge) may be insufficient. If the strength of the magnetic field is insufficient, the generation and maintenance of plasma by magnetron discharge cannot be sufficiently performed. For this reason, there arises a problem that the magnetron discharge becomes unstable.

In order to solve the above problems, the present invention has the following configuration.
(Configuration 1) A method of manufacturing a magnetic recording medium mounted on a hard disk drive, comprising: a preparation step of preparing a plurality of disk-shaped substrates; and a soft magnetic layer formation for simultaneously forming a soft magnetic layer on the plurality of substrates. And a magnetic recording layer film forming step for forming a perpendicular magnetic recording layer on the soft magnetic layer. The soft magnetic layer film forming step is performed using a film forming apparatus that forms a film by a magnetron sputtering method. A magnetic layer is formed, and a film formation apparatus is provided corresponding to each substrate, a substrate adapter for holding a plurality of substrates side by side, a target for supplying a film material of the soft magnetic layer, and a target A plurality of substrate-corresponding magnetic field generators respectively facing the corresponding substrates, and an auxiliary magnetic field generator disposed on the same side as the substrate-corresponding magnetic field generator with respect to the target, at a position different from the substrate-corresponding magnetic field generators The substrate-corresponding magnetic field generator generates a magnetic field for generating a magnetron discharge while aligning the easy magnetization axis of the soft magnetic layer formed on the corresponding substrate in the radial direction of the substrate, and the auxiliary magnetic field generator is A magnetic field for generating a magnetron discharge is generated.

  In this way, the easy axis of each substrate can be properly aligned in the radial direction of the substrate. Therefore, noise caused by the soft magnetic layer can be reduced. In addition, since the easy magnetization axis can be aligned in the radial direction of the substrate during the formation of the soft magnetic layer, it is not necessary to add a separate step of aligning the easy magnetization axis in the radial direction. Therefore, it is possible to achieve both reduction of noise such as spike noise caused by the soft magnetic layer and high mass productivity. Furthermore, by using the auxiliary magnetic field generation unit, it is possible to supplement the magnetic field generated by the substrate-corresponding magnetic field generation unit and generate a sufficient magnetic field to appropriately generate the magnetron discharge.

  A board | substrate corresponding | compatible magnetic field generation | occurrence | production part is a magnet arrangement provided corresponding to each board | substrate. The substrate-corresponding magnetic field generator generates a magnetic field that is symmetric with respect to the center of the corresponding substrate, for example. In this case, the substrate-corresponding magnetic field generator is provided at a position fixed with respect to the substrate adapter, for example. Further, the substrate-corresponding magnetic field generator may generate a magnetic field that is asymmetric with respect to the center of the corresponding substrate. In this case, in the soft magnetic layer forming step, for example, the soft magnetic layer is formed while rotating the magnetic field generating unit corresponding to the substrate about an axis that passes through the center of each substrate and is perpendicular to the target.

  Each substrate-corresponding magnetic field generator preferably generates a magnetic field having a strength that does not substantially affect the easy axis of magnetization of the soft magnetic layer formed on a substrate other than the corresponding substrate. The auxiliary magnetic field generator preferably generates a magnetic field having a strength that does not substantially affect the easy magnetization axis of the soft magnetic layer formed on each substrate.

  In order to generate magnetron discharge without using the auxiliary magnetic field generator, it is conceivable to increase the gas pressure of the sputtering gas. However, raising the gas pressure is not preferable because the film quality of the soft magnetic layer may be lowered. In order to reduce noise caused by the soft magnetic layer, a method in which the domain wall does not exist by orienting the easy axis of magnetization of the soft magnetic layer randomly in the plane can be considered. However, with the configuration 1, noise caused by the soft magnetic layer can be more appropriately reduced by aligning the easy axis of magnetization of the soft magnetic layer in the radial direction of each substrate.

  (Configuration 2) The auxiliary magnetic field generator generates a magnetic field for generating a magnetron discharge by magnetic interaction with the substrate-corresponding magnetic field generator. In this way, the erosion portion can be appropriately set in the vicinity of each substrate by linking the substrate-corresponding magnetic field generator and the auxiliary magnetic field generator. Further, for example, the installation space of the auxiliary magnetic field generation unit can be reduced as compared with the case where the auxiliary magnetic field generation unit magnetically independent from the substrate-corresponding magnetic field generation unit is provided.

  (Configuration 3) Each substrate-corresponding magnetic field generator has a first magnetic pole portion provided at a position near the center of the corresponding substrate with the first magnetic pole facing the target, and a second opposite to the first magnetic pole. And the second magnetic pole portion provided so as to surround the outer periphery of the first magnetic pole portion, and the auxiliary magnetic field generation portion faces the first magnetic pole toward the target and corresponds to each substrate. It is provided so as to surround the outer periphery of the second magnetic pole part of the magnetic field generation part, and generates a magnetic field for generating a magnetron discharge by magnetic interaction with the second magnetic pole part of each substrate corresponding magnetic field generation part. It has the 1st magnetic pole part for auxiliary magnetic fields.

  If it does in this way, the magnetization easy axis | shaft of a soft-magnetic layer can be appropriately aligned in the radial direction of each board | substrate by the board | substrate corresponding magnetic field generation | occurrence | production part. In addition, a magnetic field for generating a magnetron discharge can be appropriately generated in the auxiliary magnetic field generation unit in the vicinity of each substrate. In addition, surrounding the outer periphery of the first magnetic pole portion or the like means, for example, surrounding the outer side of the first magnetic pole portion or the like in a plane parallel to the target.

  (Configuration 4) The first auxiliary magnetic field magnetic pole portion has a plurality of through holes, and by accommodating a plurality of substrate corresponding magnetic field generating portions in the plurality of through holes, each substrate corresponding magnetic field generating portion. The auxiliary magnetic field generation unit includes a second auxiliary magnetic field magnetic pole portion provided so as to surround the outer periphery of the first auxiliary magnetic field magnetic pole portion with the second magnetic pole facing the target. Also have.

  In this case, a circular orbit of a cyclotron motion in which electrons orbit around each substrate is formed by the second magnetic pole portion and the first auxiliary magnetic pole portion of the substrate corresponding magnetic field generating portion. Further, the magnetic interaction between the first auxiliary magnetic field magnetic pole part and the second auxiliary magnetic field magnetic pole part forms a circular orbit of cyclotron motion in which electrons orbit around a wider area surrounding all the substrates. . Therefore, in this way, a wide range of the target surface can be set as the erosion portion.

  (Structure 5) A film forming apparatus for forming a soft magnetic layer of a magnetic recording medium mounted on a hard disk drive by a magnetron sputtering method, and a substrate for holding a plurality of substrates on which soft magnetic layers are formed side by side An adapter, a target for supplying the film material of the soft magnetic layer, a plurality of substrate-corresponding magnetic field generators respectively provided corresponding to the respective substrates and facing the corresponding substrates across the target, and the target On the same side as the substrate-corresponding magnetic field generation unit, an auxiliary magnetic field generation unit provided at a position different from the substrate-corresponding magnetic field generation unit is provided. The easy magnetization axis is aligned with the radial direction of the substrate and a magnetic field for generating a magnetron discharge is generated. The auxiliary magnetic field generator generates a magnetron discharge. To generate a magnetic field. If comprised in this way, the effect similar to the structure 1 can be acquired.

  According to the present invention, it is possible to achieve both reduction of noise caused by the soft magnetic layer and high mass productivity.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of the configuration of a perpendicular magnetic recording medium 10 manufactured by a method for manufacturing a magnetic recording medium according to an embodiment of the present invention. The perpendicular magnetic recording medium 10 is a magnetic disk mounted on a perpendicular magnetic recording type hard disk drive, and includes a substrate 12, a soft magnetic layer 14, an underlayer 15, a perpendicular magnetic recording layer 16, a protective layer 18, and a lubricating layer 20. Prepare in this order. The substrate 12 is a disk-shaped glass substrate, and is formed of aluminosilicate glass, aluminoborosilicate glass, soda lime glass, or the like. Moreover, the board | substrate 12 is a small diameter disk shaped body, such as 1 inch or 2.5 inches or less, for example. The substrate 12 may be a donut-shaped disk.

  The soft magnetic layer 14 is a layer for adjusting the magnetic circuit of the perpendicular magnetic recording layer 16, and is formed on the substrate 12 so as to face the head of the hard disk drive with the perpendicular magnetic recording layer 16 interposed therebetween. The soft magnetic layer 14 is not particularly limited as long as it is formed of a magnetic material (SUL) exhibiting soft magnetic characteristics, but has a coercive force (Hc) of, for example, 0.01 to 80 Oersted, more preferably 0.01. Has magnetic properties of ~ 50 oersted. The saturation magnetic flux density (Bs) preferably has a magnetic characteristic of 500 emu / cc to 1920 emu / cc. Examples of the material of the soft magnetic layer 14 include Fe-based and Co-based materials. For example, Fe-based soft magnetic materials such as FeTaC-based alloy, FeTaN-based alloy, FeNi-based alloy, FeCoB-based alloy and FeCo-based alloy, Co-based soft magnetic materials such as CoTaZr-based alloy and CoNbZr-based alloy, or FeCo-based alloy soft magnetic Materials and the like can be used.

  The film thickness of the soft magnetic layer 14 is, for example, 30 nm to 1000 nm, and more desirably 50 nm to 200 nm. If it is less than 30 nm, it may be difficult to form a suitable magnetic circuit between the head-perpendicular magnetic recording layer 16 and the soft magnetic layer 14, and if it exceeds 1000 nm, the surface roughness may increase. Moreover, when it exceeds 1000 nm, sputtering film formation may become difficult.

  The underlayer 15 is a layer for controlling the crystal direction of the perpendicular magnetic recording layer 16. As a material for the underlayer 15, for example, a Cr alloy or Ru can be used. The perpendicular magnetic recording layer 16 is a magnetic recording layer having an easy axis of magnetization in a direction perpendicular to the surface. The perpendicular magnetic recording layer 16 is made of, for example, a Co alloy such as CoCrPt, and is formed on the soft magnetic layer 14 with the underlayer 15 interposed therebetween. The protective layer 18 is a layer for protecting the perpendicular magnetic recording layer 16 from the impact of the head. The protective layer 18 protects the perpendicular magnetic recording layer 16 from the atmosphere. The lubrication layer 20 is a layer for improving lubricity between the head and the perpendicular magnetic recording medium 10.

  Each layer of the perpendicular magnetic recording medium 10 is preferably formed by sputtering. In particular, it is preferable to form a film by a DC magnetron sputtering method because uniform film formation is possible. The perpendicular magnetic recording medium 10 may further include layers other than those described above. For example, an adhesion layer formed of metal may be further provided between the substrate 12 and the soft magnetic layer 14. A seed layer may be further provided between the underlayer 15 and the perpendicular magnetic recording layer 16. The soft magnetic layer 14 may be a single layer or a laminated film of two or more layers that are antiferromagnetically coupled. When the soft magnetic layer 14 is a laminated film, the perpendicular magnetic recording medium 10 includes, for example, a plurality of soft magnetic layers that are antiferromagnetically coupled to each other with a Ru layer, an Ir layer, a Rh layer, or the like interposed therebetween. 14.

  Hereinafter, an example of a method for manufacturing the perpendicular magnetic recording medium 10 will be described in more detail. Except as described below, each layer of the perpendicular magnetic recording medium 10 is formed by, for example, the same or similar method as a conventionally known method. In this example, the perpendicular magnetic recording medium 10 is manufactured by a manufacturing method including a preparation process and a laminated film forming process. The preparation step is a step of preparing a plurality of substrates 12.

  The laminated film forming step is a step of sequentially forming each layer on the substrate 12, and a soft magnetic layer forming step, an under layer forming step, and a magnetic recording layer forming, which are individual film forming steps corresponding to each layer. It is divided into a process, a protective layer film forming process, and a lubricating layer film forming process.

  In the soft magnetic layer film forming step, the soft magnetic layer 14 is formed on the plurality of substrates 12 simultaneously using a film forming apparatus that performs film formation by magnetron sputtering. In addition, the underlayer film forming step, the magnetic recording layer forming step, and the protective layer forming step are performed on each substrate 12 using the same or similar film forming apparatus as the soft magnetic layer forming step, for example. 15, the perpendicular magnetic recording layer 16 and the protective layer 18 are sequentially formed. In the lubricating layer forming step, the lubricating layer 20 is formed by applying, for example, a fluorine-based liquid lubricant. The lubrication layer 20 may be formed in a film formation chamber that maintains the vacuum state when the protective layer 18 is formed after the protective layer 18 is formed.

  FIG. 2 shows an example of the configuration of a film forming apparatus 100 for forming the soft magnetic layer 14. FIG. 2A is a cross-sectional view of the film forming apparatus 100. The film forming apparatus 100 is a flat plate (planar) type DC magnetron sputtering apparatus, and includes a substrate adapter 102, a target 104, and a magnet unit 106.

  The board adapter 102 is a plate-like member for holding a plurality of boards 12. In this example, the board adapter 102 holds four boards 12. The substrate adapter 102 is transported to the film formation chamber of the film formation apparatus 100 while holding the substrates 12, and holds the plurality of substrates 12 side by side with the film formation surface of each substrate 12 facing the target 104. The target 104 and the magnet unit 106 constitute a magnetron cathode, and are provided in the film forming chamber of the film forming apparatus 100. The target 104 supplies the film material of the soft magnetic layer 14. The magnet unit 106 generates a magnetic field (leakage magnetic field) for generating a magnetron discharge necessary for the DC magnetron sputtering method. The leakage magnetic field is used to align the easy magnetization axis of the soft magnetic layer 14 formed on each substrate 12 in the radial direction of the substrate.

  FIG. 2B is a front view showing an example of the configuration of the board adapter 102. In this example, the substrate 12 has a plurality of substrate accommodating portions 202 corresponding to the plurality of substrates 12 to be held. The substrate housing portion 202 is a through hole having an outer peripheral chucking member 204 on the wall surface for pressing and fixing the substrate 12. By using such a substrate adapter 102, the film forming apparatus 100 simultaneously forms the soft magnetic layer 14 on the plurality of substrates 12.

  In this example, only one set of the target 104 and the magnet unit 106 are shown for the sake of simplicity. The film forming apparatus 100 may include a target 104 and a magnet unit 106 on both surfaces of the substrate adapter 102, respectively. With this configuration, the soft magnetic layer 14 can be simultaneously formed on both surfaces of each substrate 12.

  FIG. 3 shows a first example of the configuration of the magnet unit 106. FIG. 3A is a front view showing the configuration of the magnet unit 106. FIG. 3B is a cross-sectional view showing a state of a leakage magnetic field during film formation. In addition, the board | substrate 12 shown with the dotted line in the figure has shown the position of the board | substrate 12 hold | maintained at the board | substrate adapter 102 (refer FIG. 2). In this example, the magnet unit 106 includes a stage 306, a plurality of substrate-corresponding magnetic field generation units 302, and an auxiliary magnetic field generation unit 304. The stage 306 is a table provided in parallel with the target 104, and holds the substrate-corresponding magnetic field generation unit 302 and the auxiliary magnetic field generation unit 304 toward the target 104.

  Each of the plurality of substrate-corresponding magnetic field generators 302 has a dedicated magnet array for each substrate 12 and is provided at a position facing the corresponding substrate 12 with the target 104 interposed therebetween. In this example, each substrate-corresponding magnetic field generator 302 has a point-symmetric shape with respect to the center of the substrate 12, and includes a first magnetic pole part 402, a second magnetic pole part 404, a yoke part 406, and a base part 408.

  The first magnetic pole portion 402 is a permanent magnet having a first magnetic pole (for example, N pole) directed toward the target 104, and is provided at a position near the center of the corresponding substrate 12. In this example, the top magnetic pole portion 402 has a circular shape when viewed from above. The second magnetic pole portion 404 is a permanent magnet having a second magnetic pole (for example, an S pole) opposite to the first magnetic pole directed toward the target 104, and is closer to the outer peripheral side of the substrate 12 than the center portion. It is provided so as to surround the outer periphery. In this example, the top view shape of the second magnetic pole portion 404 is a donut shape. In addition, regarding the constituent elements of the magnet unit 106 such as the first magnetic pole unit 402 and the second magnetic pole unit 404, the top view shape is a shape when these are viewed from the target 104.

  The yoke part 406 is a soft iron plate provided between the first magnetic pole part 402 and the second magnetic pole part 404 and the stage 306. The base 408 is a base for attaching the yoke part 406 to the stage 306. By using the substrate-corresponding magnetic field generator 302 having the above-described shape, the magnetic field applied to each substrate 12 is directed in the radial direction of the substrate 12. Therefore, the easy magnetization axes of the soft magnetic layers formed on the respective substrates 12 are aligned in the radial direction.

  The auxiliary magnetic field generation unit 304 includes an auxiliary magnetic field magnetic pole part 410 (first auxiliary magnetic field magnetic pole part) and an auxiliary magnetic field magnetic pole part 412 (second auxiliary magnetic field magnetic pole part). In this example, the auxiliary magnetic field magnetic pole portion 410 is provided with each substrate-corresponding magnetic field generating portion 302 in the region excluding the outer peripheral portion on the stage 306 with the first magnetic pole (for example, the N pole) directed toward the target 104. It is provided in the part except the position where it is. The auxiliary magnetic field magnetic pole portion 410 has a through hole at a position where each substrate corresponding magnetic field generation unit 302 is provided, and each substrate corresponding magnetic field generation unit 302 is accommodated in this through hole. Thus, the auxiliary magnetic field magnetic pole part 410 surrounds the outer periphery of the second magnetic pole part 404 of each substrate-corresponding magnetic field generation part 302. Then, due to the magnetic interaction with the second magnetic pole portion 404 of each substrate-corresponding magnetic field generation unit 302, the auxiliary magnetic field magnetic pole portion 410 forms a trajectory that circulates electrons that make cyclotron motion in the vicinity of each substrate 12. .

  The auxiliary magnetic field magnetic pole part 412 is provided so as to surround the outer periphery of the auxiliary magnetic field magnetic pole part 410 along the outer periphery of the stage 306 with the second magnetic pole (for example, the S pole) facing the target 104. The top-view shape of the auxiliary magnetic field magnetic pole portion 412 is a donut shape. The auxiliary magnetic field magnetic pole portion 412 forms a trajectory for circulating electrons that make cyclotron motion in a wider area surrounding all the substrates 12 by magnetic interaction with the auxiliary magnetic field magnetic pole portion 410. In addition, it is preferable that the auxiliary magnetic field magnetic pole part 410 and the auxiliary magnetic field magnetic pole part 412 generate a magnetic field having such an intensity that electrons can make at least one round of each orbit when there is no collision with the sputtering gas.

  With the above configuration, the substrate-corresponding magnetic field generation unit 302 and the auxiliary magnetic field generation unit 304 generate a leakage magnetic field as indicated by a dotted arrow in FIG. Thereby, the substrate-corresponding magnetic field generator 302 generates a magnetic field for aligning the easy magnetization axis of the soft magnetic layer 14 formed on the corresponding substrate 12 in the radial direction of the substrate 12. Therefore, according to this example, noise such as spike noise caused by the soft magnetic layer 14 can be reduced. In this example, the auxiliary magnetic field magnetic pole portion 410 surrounds the outer periphery of the substrate-corresponding magnetic field generating portion 302 symmetrically. Therefore, it is possible to prevent the magnetic field generated by the auxiliary magnetic field generation unit 304 from affecting the control of the easy magnetization axis of the soft magnetic layer 14.

  Further, the magnetic field generated by the substrate-corresponding magnetic field generator 302 also functions as a magnetic field for generating magnetron discharge. In addition to this magnetic field, the auxiliary magnetic field generation unit 304 includes the magnetic interaction between the second magnetic pole portion 404 and the auxiliary magnetic field magnetic pole portion 410 of each substrate corresponding magnetic field generation unit 302, and the auxiliary magnetic field magnetic pole portion 410. A magnetic field for generating a magnetron discharge is generated by the magnetic interaction between the magnetic field portion 412 and the auxiliary magnetic field magnetic pole portion 412. Thereby, the magnetic field for generating the magnetron discharge which is insufficient only by the substrate corresponding magnetic field generation unit 302 can be supplemented. Therefore, according to this example, even when the substrate-corresponding magnetic field generator 302 corresponding to the small substrate 12 is used, a stable magnetron discharge is generated on the surface of the target 104 and the soft magnetic layer 14 is formed. Can be performed appropriately. In addition, this makes it possible to achieve both noise reduction due to the soft magnetic layer 14 and high mass productivity.

  When the soft magnetic layer 14 is formed, the target 104 consumes an erosion portion that receives a leakage magnetic field from the substrate-corresponding magnetic field generation unit 302 and the auxiliary magnetic field generation unit 304. For this reason, it is preferable to rotate the target 104 after the film formation of the soft magnetic layer 14 is finished and the magnetron discharge is finished and before the substrate adapter 102 holding the next substrate 12 is transferred to the film formation chamber. In this way, the area consumed in the target 104 can be made wide and uniform. This also increases the usage efficiency of the target 104, extends the life, and further improves mass productivity.

  FIG. 4 shows a second example of the configuration of the magnet unit 106. FIG. 4A is a front view showing the configuration of the magnet unit 106. FIG. 4B is a cross-sectional view showing a state of a leakage magnetic field during film formation. Except for the points described below, the same or similar components in FIG. 4 as those in FIG. 3 are denoted by the same reference numerals as those in FIG.

  In the present example, the first magnetic pole part 402 and the second magnetic pole part 404 are asymmetrical with respect to the center of the substrate 12. The first magnetic pole portion 402 has a substantially quadrangular shape when viewed from the top, and is provided at a position where the centers of the first magnetic pole portion 402 and the center of the substrate 12 are overlapped with each other with respect to the substrate 12. The second magnetic pole portion 404 has a shape obtained by deforming a donut shape into a substantially square shape, and is provided at a position surrounding the first magnetic pole portion 402 with the first magnetic pole portion 402 as a center.

  In this example, the substrate-corresponding magnetic field generation unit 302 further includes a rotation driving unit 414 between the yoke unit 406 and the base unit 408. The rotation driving unit 414 rotates the first magnetic pole part 402, the second magnetic pole part 404, and the yoke part 406 with respect to the center of the substrate 12 in the direction indicated by the arrow in the drawing, for example. With this configuration, the range of the applied magnetic field on the surface of the target 104 can be widened, and the usage efficiency of the target 104 can be improved.

  In addition, the magnetic fields generated by the first magnetic pole part 402 and the second magnetic pole part 404 are averaged by this rotational motion and are point-symmetric with respect to the center of the substrate 12. Thereby, also in this example, the magnetic field applied to each substrate 12 is directed in the radial direction, and the easy magnetization axes of the soft magnetic layers formed on the respective substrates 12 are aligned in the radial direction. Therefore, also in this example, it is possible to achieve both reduction of noise caused by the soft magnetic layer 14 and high mass productivity.

  In addition, the shape of the 1st magnetic pole part 402 and the 2nd magnetic pole part 404 is not limited to the shape shown in figure. For example, the top view shape of the first magnetic pole portion 402 may be a substantially horseshoe shape, as in FIG. In this case, the second magnetic pole portion 404 surrounds the first magnetic pole portion 402 along the outer periphery of the first magnetic pole portion 402, for example, as in FIG.

  FIG. 5 shows a further modification of the configuration of the magnet unit 106. FIG. 5A shows a third example of the configuration of the magnet unit 106. FIG. 5B shows a fourth example of the configuration of the magnet unit 106. In these modifications, the board adapter 102 (see FIG. 2) holds five boards 12. In response to this, the magnet unit 106 includes five substrate-corresponding magnetic field generation units 302. In the case shown in FIG. 5A, each substrate-corresponding magnetic field generator 302 has the same or similar configuration as the substrate-corresponding magnetic field generator 302 described with reference to FIG. 5B, each substrate-corresponding magnetic field generator 302 has the same or similar configuration as the substrate-corresponding magnetic field generator 302 described with reference to FIG. In these cases as well, both noise reduction due to the soft magnetic layer 14 and high mass productivity can be achieved.

  FIG. 6 shows a fifth example of the configuration of the magnet unit 106. In this example, the 1st magnetic pole part 402 and the 2nd magnetic pole part 404 are comprised by the magnetic pole of an electromagnet. The substrate-corresponding magnetic field generation unit 302 generates a magnetic field that is point-symmetric with respect to the center of the substrate 12, for example. The substrate-corresponding magnetic field generator 302 preferably generates the same or similar magnetic field as the substrate-corresponding magnetic field generator 302 described with reference to FIG. Also in this case, both noise reduction due to the soft magnetic layer 14 and high mass productivity can be achieved.

  Note that the substrate-corresponding magnetic field generation unit 302 may generate a magnetic field that is asymmetric with respect to the center of the substrate 12, such as the same or similar magnetic field as the substrate-corresponding magnetic field generation unit 302 described with reference to FIG. In this case, the substrate-corresponding magnetic field generation unit 302 further includes, for example, a rotation drive unit 414 (see FIG. 4). Moreover, you may comprise the auxiliary magnetic field generation part 304 with an electromagnet.

Example 1
A soft magnetic layer was formed on the substrate by using the film forming apparatus described with reference to FIGS. The sputtering gas was Ar, and the gas pressure was less than 1 Pa (about 0.7 Pa). In Example 1, stable magnetron discharge was generated, and the soft magnetic layer could be appropriately formed. The easy magnetization axes of the soft magnetic layers were aligned in the radial direction of the substrate.

(Comparative Example 1)
A soft magnetic layer was formed on the substrate in the same manner as in Example 1 except that the auxiliary magnetic field generator was not provided. However, stable magnetron discharge could not be generated and the soft magnetic layer could not be formed properly.

(Comparative Example 2)
A soft magnetic layer was formed on the substrate in the same manner as in Example 1 except that the auxiliary magnetic field generator was not provided and the gas pressure of the sputtering gas was 3 Pa. In Comparative Example 2, a stable magnetron discharge could be generated. However, since the gas pressure was too high, a large number of micro defects were generated in the soft magnetic layer, and an appropriate soft magnetic layer could not be formed.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The present invention can be suitably used for, for example, a magnetic recording medium mounted on a hard disk drive.

1 is a schematic diagram showing an example of a configuration of a perpendicular magnetic recording medium 10 manufactured by a magnetic recording medium manufacturing method according to an embodiment of the present invention. 1 is a diagram illustrating an example of a configuration of a film forming apparatus 100 for forming a soft magnetic layer 14. FIG. 2A is a cross-sectional view of the film forming apparatus 100. FIG. 2B is a front view showing an example of the configuration of the board adapter 102. 3 is a diagram illustrating a first example of a configuration of a magnet unit 106. FIG. FIG. 3A is a front view showing the configuration of the magnet unit 106. FIG. 3B is a cross-sectional view showing a state of a leakage magnetic field during film formation. 6 is a diagram illustrating a second example of a configuration of a magnet unit 106. FIG. FIG. 4A is a front view showing the configuration of the magnet unit 106. FIG. 4B is a cross-sectional view showing a state of a leakage magnetic field during film formation. The further modification of the structure of the magnet part 106 is shown. FIG. 5A shows a third example of the configuration of the magnet unit 106. FIG. 5B shows a fourth example of the configuration of the magnet unit 106. It is a figure which shows the 5th example of a structure of the magnet part. An example of a structure of a film formation apparatus 800 that performs film formation on a plurality of substrates simultaneously is shown. FIG. 7A is a cross-sectional view of the film forming apparatus 800. FIG. 7B is a plan view showing the magnet unit 806. It is a figure which shows the direction where the easy axis of a soft magnetic layer is controlled in each board | substrate 12. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Perpendicular magnetic recording medium, 12 ... Substrate, 14 ... Soft magnetic layer, 15 ... Underlayer, 16 ... Perpendicular magnetic recording layer, 18 ... Protective layer, 20 ... Lubricating layer, 100 ... Film forming apparatus, 102 ... Substrate adapter, 104 ... Target, 106 ... Magnet part, 202 ... Substrate housing part, 204 ... Peripheral chucking member, 302 ..Substrate-corresponding magnetic field generator, 304 ... auxiliary magnetic field generator, 306 ... stage, 402 ... first magnetic pole, 404 ... second magnetic pole, 406 ... yoke, 408 ···, 410 ··· Magnetic pole portion for auxiliary magnetic field, 412 ··· Magnetic pole portion for auxiliary magnetic field, 414 ··· Rotation drive portion, 800 ··· Film forming device, 802 ··· Substrate adapter, 804 · ..Target, 806 ... Magnet part, 808 ... Stage, 81 ... field generating unit, 812 ... substrate, 906 ... leakage magnetic field, 908 ... permanent magnet, 910 ... permanent magnet, 912 ... arrow

Claims (1)

A method of manufacturing a magnetic recording medium mounted on a hard disk drive,
A preparation step of preparing a plurality of disk-shaped substrates;
A soft magnetic layer forming step of simultaneously forming a soft magnetic layer on a plurality of the substrates;
A magnetic recording layer forming step of forming a perpendicular magnetic recording layer on the soft magnetic layer;
With
In the soft magnetic layer film forming step, the soft magnetic layer is formed using a film forming apparatus that forms a film by a magnetron sputtering method.
The film forming apparatus includes:
A board adapter for holding the plurality of boards side by side;
A target for supplying the film material of the soft magnetic layer;
A plurality of substrate-corresponding magnetic field generators respectively provided corresponding to the respective substrates and facing the corresponding substrates across the target;
An auxiliary magnetic field generator provided on the same side as the substrate-corresponding magnetic field generator with respect to the target, at a position different from the substrate-corresponding magnetic field generator;
With
The substrate-corresponding magnetic field generator generates a magnetic field for generating a magnetron discharge while aligning the easy magnetization axis of the soft magnetic layer formed on the corresponding substrate with the radial direction of the substrate.
,
The auxiliary magnetic field generator generates a magnetic field for generating a magnetron discharge,
The auxiliary magnetic field generator generates a magnetic field for generating a magnetron discharge by magnetic interaction with the substrate-corresponding magnetic field generator.
Each substrate-corresponding magnetic field generator is
A first magnetic pole portion provided at a position near the center of the corresponding substrate with the first magnetic pole directed toward the target;
A second magnetic pole portion provided to surround an outer periphery of the first magnetic pole portion with a second magnetic pole opposite to the first magnetic pole facing the target;
Have
The auxiliary magnetic field generation unit is provided so as to surround the outer periphery of the second magnetic pole part of each of the substrate-corresponding magnetic field generation parts with the first magnetic pole facing the target, and each of the substrate-corresponding magnetic fields A first auxiliary magnetic pole portion for generating a magnetic field for generating a magnetron discharge by magnetic interaction with the second magnetic pole portion of the generating portion;
The first auxiliary magnetic field magnetic pole portion has a plurality of through holes, and the plurality of substrate-corresponding magnetic field generators are accommodated in the plurality of through-holes, whereby the substrate-corresponding magnetic field generators Surrounding the second magnetic pole,
The auxiliary magnetic field generation unit further includes a second auxiliary magnetic field magnetic pole portion provided so as to surround the outer periphery of the first auxiliary magnetic field magnetic pole portion with the second magnetic pole directed toward the target. A method for manufacturing a magnetic recording medium.

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