Heating device and magnetic recording medium production method

Abstract

To provide a heating device which can heat a surface of a workpiece having a disk-shape in whose center part a hole is formed, with high productivity and at high uniformity.SOLUTION: A heating device for heating a workpiece by radiating light to the workpiece is provided. The heating device comprises a radiating part facing at least one main surface of a pair of main surfaces, and radiating light to the workpiece. The radiating part has multiple light emission elements on the surface facing the at least one main surface of the workpiece. The surface of the radiating part facing the workpiece has: a first area including the position corresponding to the center of the workpiece; a second area surrounding the first area from outside; and a third area surrounding the second area from outside and including the position corresponding to the outer periphery of the workpiece. A light emission amount per unit area in the third area is greater than those of the first area and the second area.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a heating device and a method for manufacturing a magnetic recording medium. [Background technology]

[0002] Magnetic recording media are widely used as recording media for recording and storing various data. For example, a magnetic recording medium is configured such that a magnetic layer is formed on a soft magnetic layer and an underlayer formed on a substrate.

[0003] In response to the demand for improved recording density, the structure of the magnetic layer is being refined. In addition, in order to improve recording quality, materials with high thermal fluctuation resistance, such as FePt alloys, are used for the magnetic layer. When using such materials, in the manufacturing process of the magnetic recording medium, after the magnetic layer is formed, a heat treatment is often performed to regularize the magnetic layer.

[0004] For example, Patent Document 1 describes a film formation apparatus in which one or more substrate holders for holding substrates, a thin film material source, and a shutter arranged in a film formation chamber so as to be retractable between the substrate holder and the thin film material source are arranged, and in which one or more surface heaters for heating the substrate are installed on the shutter in correspondence with the substrate.

[0005] For example, Patent Document 2 discloses a heating light source device in which a plurality of heating light source modules, each of which includes a plurality of light emitting elements and a cooling member, are arranged. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-129326 A [Patent Document 2] JP 2022-172776 A Summary of the Invention [Problem to be solved by the invention]

[0007] There is a demand for reducing the manufacturing cost of magnetic recording media. In addition, disk-shaped magnetic recording media with a hole in the center are widely used. Therefore, the workpieces in the manufacturing process often have a similar shape.

[0008] Patent Document 1 describes a planar heater in which resistors such as pyrolytic graphite (PG) are formed in a predetermined pattern on an insulating substrate such as pyrolytic boron nitride (PBN). Such heaters are very expensive, which leads to increased manufacturing costs for magnetic recording media. In addition, it is difficult to control the distribution of the amount of heat within the surface. As a result, defective products may be produced due to excessive heating. In addition, when a workpiece with a hole formed in the center is heated, the components inside the device are easily heated due to the amount of infrared rays passing through the hole, which requires effort to protect the device and increases costs.

[0009] Patent Document 2 describes a configuration in which LED elements are used as light-emitting elements. However, since heat escapes from the outer peripheral edge of the substrate during heating, the arrangement of the light-emitting elements disclosed in Patent Document 2 results in a lower temperature near the outer periphery of the substrate compared to the inside.

[0010] Therefore, an object of one embodiment of the present invention is to provide a heating device that can heat the surface of a disk-shaped workpiece with a hole formed in the center with high productivity and high uniformity. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention has the following configuration.

[0012] One embodiment of the present invention is a heating device that heats a workpiece by irradiating light onto a workpiece having a disk shape with a hole formed in the center and a pair of opposing main surfaces, the heating device having an irradiation unit that faces at least one of the pair of main surfaces and irradiates the light onto the workpiece, the irradiation unit having a plurality of light-emitting elements on a surface facing at least one of the main surfaces of the workpiece, the surface of the irradiation unit facing the workpiece including a first region including a position corresponding to the center of the workpiece, a second region that surrounds the first region from the outside, and a third region that surrounds the second region from the outside and includes a position corresponding to the outer periphery of the workpiece, the amount of light emitted per unit area in the third region being greater than the amount of light emitted per unit area in the first region and the amount of light emitted per unit area in the second region. Effect of the Invention

[0013] According to one embodiment of the present invention, it is possible to provide a heating device capable of heating the surface of a disk-shaped workpiece having a hole formed in the center with high productivity and high uniformity. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing an example of the configuration of a magnetic recording medium obtained by a method for producing a magnetic recording medium according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a flow diagram showing an example of a method for manufacturing a magnetic recording medium according to a first embodiment of the present invention. [Diagram 3] FIG. 1 is a diagram showing a schematic diagram of an example of a magnetic recording medium manufacturing apparatus according to a first embodiment of the present invention. [Figure 4] FIG. 1 is a schematic plan view showing an example of the configuration of a heating device according to a first embodiment of the present invention. [Diagram 5] 1 is a schematic diagram showing an example of the configuration of an irradiation unit of a heating device according to a first embodiment of the present invention, as viewed from the workpiece side in a direction perpendicular to a main surface of the workpiece. [Figure 6]FIG. 4 is a schematic diagram showing another example of the configuration of the irradiation unit of the heating device according to the first embodiment of the present invention, as viewed from the workpiece side in a direction perpendicular to the main surface of the workpiece. [Figure 7] 7 is a conceptual diagram showing an example of a configuration for controlling an irradiating unit shown in FIG. 6. [Figure 8] 7 is a conceptual diagram showing another example of the configuration for controlling the irradiating unit shown in FIG. 6. FIG. [Figure 9] FIG. 11 is a diagram showing an example of the distribution of the amount of light irradiated onto a main surface of a workpiece by an irradiating unit of a heating device according to a second embodiment of the present invention. [Figure 10] 13 is a diagram showing a modified example of the distribution of the amount of light irradiated onto the main surface of the workpiece by the irradiating unit of the heating device according to the second embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the configuration described below. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as the actual ones.

[0016] The term "workpiece" refers collectively to the state of materials from substrate 11 (described later) until they become magnetic recording medium 1, and both the substrate 11 state and the magnetic recording medium 1 state may be called a workpiece.

[0017] [First embodiment] <Configuration of magnetic recording medium> 1 is a schematic cross-sectional view showing an example of the layer structure of a magnetic recording medium obtained by the method for producing a magnetic recording medium according to the present embodiment. The magnetic recording medium described below is preferably suitable for a perpendicular magnetic recording method, but may be suitable for other magnetic recording methods.

[0018] The magnetic recording medium 1 according to this example has a substrate 11, and a soft magnetic layer 12, an underlayer 13, a magnetic layer 14, and a protective layer 15, which are formed on the substrate 11 in this order from the substrate 11 side. Each of these layers may be formed on one or both of the main surfaces of the substrate 11.

[0019] The configuration of the magnetic recording medium 1 obtained by the manufacturing method of this embodiment is not limited to this configuration, and layers other than the magnetic layer 14 and the underlayer 13 do not have to be formed if they are not required, and layers other than the layers listed above may be formed if necessary.

[0020] In addition, in FIG. 1, for convenience of explanation, the protective layer 15 side is sometimes referred to as the upper side or the front side, and the substrate 11 side is sometimes referred to as the lower side or the inner side.

[0021] The substrate 11 is preferably in the shape of a disk with a hole formed in the center. The material constituting the substrate 11 is preferably a non-magnetic material. Examples of the material constituting the substrate 11 include an Al alloy, crystallized glass, and amorphous glass. The substrate 11 may also be configured such that a coating layer such as plating is formed on a base material.

[0022] The soft magnetic layer 12 is provided on the substrate 11, and when recording a signal on the magnetic recording medium 1, has the function of guiding the recording magnetic field from the magnetic head and efficiently applying the perpendicular component of the recording magnetic field to the magnetic layer 14. Examples of materials constituting the soft magnetic layer 12 include soft magnetic alloys such as FeCo-based alloys, CoZrNb-based alloys, and CoTaZr-based alloys.

[0023] The soft magnetic layer 12 preferably has an amorphous structure, which enhances the soft magnetic properties of the soft magnetic layer 12 and improves the surface smoothness, thereby reducing the flying height of the magnetic head and further improving the recording density of the magnetic recording medium 1.

[0024] The soft magnetic layer 12 may be composed of one layer or may have a configuration including multiple layers. When the soft magnetic layer 12 includes multiple layers forming an antiferromagnetic exchange coupling (AFC) film, it is preferable that a nonmagnetic layer such as a Ru film is formed between each layer.

[0025] The total thickness of the soft magnetic layer 12 is appropriately determined depending on the electromagnetic conversion characteristics of the magnetic recording medium 1, but is preferably, for example, 20 nm to 120 nm.

[0026] The underlayer 13 promotes the orientation of the magnetic grains contained in the magnetic layer 14. When the magnetic layer 14 contains magnetic grains having an L10 structure, the underlayer 13 is preferably capable of (001) orienting the magnetic grains.

[0027] Examples of materials contained in the underlayer 13 include NaCl type compounds and bcc alloys. Examples of NaCl type compounds include MgO. Examples of bcc alloys include Cr alloys, W alloys, and Mo alloys.

[0028] Underlayer 13 may be composed of one layer or may have a configuration including multiple layers. When underlayer 13 includes multiple layers, it is preferable, but not limited to, that the lower layer contains a bcc alloy and the uppermost layer contains a NaCl-type compound.

[0029] The magnetic layer 14 is a layer that contains magnetic particles and in which information is recorded. The magnetic particles preferably have an L10 structure. Examples of magnetic particles having an L10 structure include FePt-based alloy particles containing an FePt-based alloy, and CoPt-based alloy particles containing a CoPt-based alloy. In the magnetic layer 14, a granular structure is preferably formed.

[0030] The magnetic layer 14 may be composed of one layer, or may have a configuration including multiple layers. When the magnetic layer 14 includes multiple layers, each layer may be formed using the same type of material, or may be formed using different types of materials. In addition, a non-magnetic layer may be included between each of the multiple magnetic layers 14. The non-magnetic layer may be formed using a general material used in magnetic recording media.

[0031] The protective layer 15 protects layers underneath, such as the magnetic layer 14, from contact between components, such as a magnetic head, and the magnetic recording medium 1. Examples of materials for forming the protective layer 15 include carbon materials, such as diamond-like carbon (DLC).

[0032] The magnetic recording medium 1 may include a lubricant layer (not shown) on the protective layer 15. The lubricant layer may be formed from a material such as a resin such as perfluoropolyether.

[0033] <Method of manufacturing magnetic recording medium> 2 is a flow diagram showing an example of a method for manufacturing the magnetic recording medium 1 according to the first embodiment of the present invention. The method for manufacturing the magnetic recording medium 1 according to this example of the present embodiment includes a soft magnetic layer forming step S101, an underlayer forming step S102, a magnetic layer forming step S103, a heating step S104, and a protective layer forming step S105.

[0034] The method for manufacturing the magnetic recording medium 1 according to this embodiment may include other steps as necessary. Furthermore, the method for manufacturing the magnetic recording medium 1 according to this embodiment may not require at least one of the steps other than the magnetic layer step S103 and the heating step S104, depending on the specifications of the magnetic recording medium, etc. Furthermore, the treatment performed in the heating step S104 (described in detail below) may be performed after a step other than the magnetic layer forming step S103.

[0035] In the soft magnetic layer forming step S101, the soft magnetic layer 12 is formed on the main surface of the substrate 11. The configurations of the substrate 11 and the soft magnetic layer 12 are as described above.

[0036] The method for forming the soft magnetic layer 12 includes, but is not limited to, DC (Direct Current) sputtering. When the soft magnetic layer 12 includes multiple layers, the methods for forming the layers may be the same or different. In order to improve the adhesion of the soft magnetic layer to the substrate 11 (workpiece W), an adhesion layer may be formed before the soft magnetic layer forming step S101.

[0037] In the underlayer forming step S102, the underlayer 13 is formed on the workpiece W on which the soft magnetic layer 12 has been formed. The configuration of the underlayer 13 is as described above.

[0038] The method for forming the underlayer 13 includes, but is not limited to, DC sputtering. When the underlayer 13 includes a plurality of layers, the respective layers may be formed by the same method or different methods.

[0039] In the magnetic layer forming step S103, the magnetic layer 14 is formed on the workpiece W on which the underlayer 13 has been formed. The configuration of the magnetic layer 14 is as described above.

[0040] Methods for forming the magnetic layer 14 include, but are not limited to, DC sputtering. When the magnetic layer 14 includes multiple layers, the methods for forming the layers may be the same or different.

[0041] 2, the heating step S104 is performed by irradiating the workpiece W on which the magnetic layer 14 is formed with light to heat the workpiece W. The heating step S104 enhances the crystal orientation of the magnetic layer 14. The heating method will be described in detail later. After the heating step S104, the workpiece W may be cooled as necessary.

[0042] When multiple layers are formed as the magnetic layer 14, the heat treatment according to the method performed in the heating step S104 is preferably performed after the formation of at least one of the layers, and is preferably performed after the formation of at least the lowermost layer. Also, the heat treatment according to the method performed in the heating step S104 may be performed each time one magnetic layer 14 is formed.

[0043] In the protective layer forming step S105, a protective layer 15 is formed on the workpiece W that has been subjected to the heating step S104. The configuration of the protective layer 15 is as described above. Methods for forming the protective layer 15 include, but are not limited to, chemical vapor deposition (CVD) and the like.

[0044] The workpiece W on which the protective layer S105 has been formed may be further subjected to a surface treatment, a lubricating layer may be formed, or other treatments may be performed.

[0045] <Magnetic recording medium manufacturing equipment> 3 is a diagram showing a schematic diagram of an example of a manufacturing apparatus for the magnetic recording medium 1 according to the first embodiment of the present invention. The manufacturing apparatus 3 for the magnetic recording medium 1 according to this embodiment (hereinafter, sometimes referred to as the manufacturing apparatus 3) includes a work input section 31, a soft magnetic layer forming section 32, a base layer forming section 33, a magnetic layer forming section 34, a heating section 35, a protective layer forming section 36, and a work removal section 37.

[0046] The manufacturing apparatus 3 according to this example is an in-line type manufacturing apparatus in which all processes performed on the workpiece W are performed in a chamber. In FIG. 3, the arrow indicates the direction in which the workpiece W moves in the manufacturing apparatus 3. The workpiece input section 31, the soft magnetic layer forming section 32, the underlayer forming section 33, the magnetic layer forming section 34, the heating section 35, the protective layer forming section 36, and the workpiece removal section 37 may each have a chamber in which a film formation process is performed on the workpiece W. In the manufacturing apparatus 3, the workpiece W input from the workpiece input section 31 passes through each chamber of the manufacturing apparatus 3 while being held by the carrier C, and is removed from the manufacturing apparatus 3 from the workpiece removal section 37 to the outside. Note that this configuration is merely an example, and the manufacturing apparatus 3 for the magnetic recording medium 1 according to this embodiment is not limited to this in-line type.

[0047] The workpiece W according to this embodiment has a disk shape with a hole H formed in the center. The hole H is preferably circular, and it is more preferable that the center of the hole H and the center of the workpiece W coincide with each other.

[0048] The radius of the workpiece W is preferably 25 mm or more, more preferably 40 mm or more, and even more preferably 45 mm or more. The radius of the workpiece W is preferably 80 mm or less, more preferably 60 mm or less, and even more preferably 50 mm or less.

[0049] The radius of the hole H is preferably 6.0 mm or more, more preferably 8.0 mm or more, and even more preferably 10 mm or more. The radius of the hole H is preferably 20 mm or less, more preferably 17 mm or less, and even more preferably 14 mm or less.

[0050] The workpiece input section 31 has an opening / closing mechanism, and the opening / closing mechanism is opened when the workpiece W (substrate 11) is input into the manufacturing apparatus 3. One example of a specific configuration of the workpiece input section 31 is a configuration including a load chamber (not shown).

[0051] When the workpiece W is loaded into the load chamber, the load chamber is opened so as to be in communication with the outside of the manufacturing apparatus 3. When the workpiece W is loaded into the load chamber, the inside of the load chamber is closed and the pressure inside the load chamber is reduced. The pressure is reduced by a pressure reducing device such as a pump. When the pressure inside the load chamber has sufficiently decreased, the load chamber is opened so as to be in communication with the inside of the manufacturing apparatus 3, in the example shown in this figure, the soft magnetic layer forming section 32, and the workpiece W is transported to the soft magnetic layer forming section 32.

[0052] This configuration maintains a reduced pressure state inside the manufacturing apparatus 3. The configuration and operation of the workpiece input unit 31 described here are merely examples and are not limited thereto. In order to further increase the airtightness inside the manufacturing apparatus 3, the workpiece input unit 31 may include a plurality of chambers connected in series, for example, a load chamber and a load sub-chamber.

[0053] The soft magnetic layer forming section 32 performs a soft magnetic layer forming step S101, the underlayer forming section 33 performs an underlayer forming step S102, and the magnetic layer forming section 34 performs a magnetic layer forming step S103, each step being as described above.

[0054] Each of the soft magnetic layer forming section 32, the underlayer forming section 33, and the magnetic layer forming section 34 may be configured to form only one layer, or may be configured to form two or more layers. The lamination process of each layer in the soft magnetic layer forming section 32, the underlayer forming section 33, and the magnetic layer forming section 34 is preferably performed in a chamber. In each of these sections, in which multiple layers are formed, the formation of each layer is preferably performed in a separate chamber. That is, each section is preferably provided with a number of chambers corresponding to the number of layers formed therein. Each chamber may be independently provided with a pressure reducing device. The pressure reducing device is not particularly limited, but may be a pump or the like.

[0055] The heating step S104 is performed in the heating section 35. The heating step S104 is as described above. The heating section 35 includes a heating device. The configuration of the heating device will be described in detail later.

[0056] In the protective layer forming section 36, the protective layer forming step S105 is performed. The protective layer forming step S105 is as described above. The lamination process in the protective layer forming section 36 is preferably performed in a chamber. When a plurality of layers are formed as the protective layer 15, it is preferable that each layer is formed in a separate chamber. That is, it is preferable that the protective layer forming section 36 includes a number of chambers corresponding to the number of layers to be formed therein. Each chamber may be independently provided with a pressure reducing device. The pressure reducing device is not particularly limited, but may be a pump or the like.

[0057] The workpiece unloading section 37 has an opening / closing mechanism, and the opening / closing mechanism is opened when the workpiece W is unloaded from the manufacturing apparatus 3. One example of a specific configuration of the workpiece unloading section 37 is a configuration including an unload chamber (not shown).

[0058] The unload chamber is opened when the workpiece W is transported from the protective layer forming section 36 to the workpiece removal section 37. When the workpiece W is carried into the unload chamber, the opening and closing mechanism between the unload chamber and the protective layer forming section 36 is closed, and then the pressure in the unload chamber is increased. When the pressure in the unload chamber has increased sufficiently, the unload chamber becomes capable of communicating with the outside, and the workpiece W is removed outside the manufacturing apparatus 3. The pressure in the unload chamber when it becomes capable of communicating with the outside is not limited, but it is preferable that it has increased to atmospheric pressure.

[0059] <Heating device> Fig. 4 is a schematic diagram in a plan view showing an example of the configuration of the heating device according to the first embodiment of the present invention. The heating device 4 according to this embodiment has a disk-like shape with a hole formed in the center, and heats the workpiece W by irradiating light onto the workpiece W having a pair of main surfaces facing each other. In the example of Fig. 3, the heating device 4 is provided in a heating section 35. The heating device 4 is an example of a device used to carry out the above heating method (heating step), but there is no need for a corresponding relationship between the heating device 4 and the above heating method.

[0060] 4 includes a chamber 40, a workpiece loading section 41, a workpiece unloading section 42, a workpiece holding section 43, an irradiation section 44, and a controller 45. Note that the configuration described below is merely an example, and the heating device 4 according to this embodiment is not limited to this configuration.

[0061] It is preferable that the interior of the chamber 40 is kept in a reduced pressure state lower than atmospheric pressure when the workpiece W is heated. The chamber 40 is connected to a pressure reducing device (not shown). An example of the pressure reducing device is a pump. Note that this configuration is merely one example, and the chamber 40 does not need to be connected to a pressure reducing device in cases where it is not necessary to perform heating in a reduced pressure environment, or where the entire path of the workpiece W in the manufacturing apparatus 3 for the magnetic recording medium 1 is generally reduced pressure, etc.

[0062] The air pressure inside the chamber 40 in the reduced pressure state is not limited, but is preferably 10 Pa or less. This is to suppress heat loss caused by the gas inside the chamber 40 being heated. Also, this is to suppress heating of the walls of the chamber 40 and the components inside the chamber 40 due to heat conduction by the gas inside the chamber 40. Furthermore, this is to suppress an increase in air pressure inside the front and rear chambers when the workpiece W is moved if the front and rear chambers are kept in a reduced pressure state.

[0063] The chamber 40 includes an irradiation window 401 between the irradiation unit 44 and the workpiece W, and the irradiation window 401 is a part of a partition wall that separates the inside and outside of the chamber 40. That is, in the configuration of this example, the workpiece W is inside the chamber 40, and the irradiation unit 44 is outside the chamber 40. The irradiation window 401 transmits light from the irradiation unit 44. The irradiation window 401 can be made of, for example, quartz.

[0064] This configuration makes it possible to prevent an increase in pressure within the chamber 40 due to gas or the like generated when the light emitting element 44L (details of which will be described later) provided in the irradiation section 44 emits light, or to prevent the chamber 40 from being contaminated.

[0065] The workpiece loading section 41 is opened when the workpiece W is loaded into the chamber 40, and is closed when the workpiece W is loaded into the chamber 40. The workpiece unloading section 42 is closed while the workpiece W is being heated, and is opened when the workpiece W is unloaded from the chamber 40. That is, in the heating process of the workpiece W, the workpiece loading section 41 and the workpiece unloading section 42 are closed. In the heating process, in order to maintain a predetermined air pressure inside the chamber 40, the pressure inside the chamber 40 may be reduced by a pressure reducing device or the like with the workpiece loading section 41 and the workpiece unloading section 42 closed.

[0066] The workpiece holding unit 43 holds the workpiece W at a predetermined position so that the main surface of the workpiece W faces the irradiation unit 44 described below. In the configuration shown in Fig. 4, the workpiece holding unit 43 holds two workpieces W, but the number of workpieces W held by the workpiece holding unit 43 is not limited.

[0067] In this example, as an example, the workpiece W is configured to move between each chamber while being held by a carrier C. That is, in this example, the carrier C corresponds to the workpiece holding unit 43. In the heating process, the carrier C stops at a position where the main surface of each workpiece W faces the corresponding irradiation unit 44.

[0068] The irradiation unit 44 faces at least one of the pair of main surfaces of the workpiece W and irradiates light onto the workpiece W. In this example, a pair of irradiation units 44 are provided facing each of the pair of main surfaces (both main surfaces) of the workpiece W, and each has the same configuration. Each irradiation unit 44 irradiates light onto the corresponding main surface (opposing main surface) of the workpiece W. However, this configuration is merely an example, and for example, the irradiation unit 44 may be provided only on one main surface side of the workpiece W. For example, when a pair of irradiation units 44 are provided facing each of the pair of main surfaces of the workpiece W, the irradiation unit 44 facing one main surface (front surface) of the workpiece W and the irradiation unit 44 facing the other main surface (rear surface) may have different configurations. Details of the configuration of the irradiation unit 44 will be described later.

[0069] The controller 45 issues commands to control the emission (on and off) of the light-emitting element 44L included in the irradiation unit 44. The controller 45 includes a storage unit, a calculation unit, and an interface, which are not shown here. The controller 45 may include other components.

[0070] The storage unit includes, for example, a ROM or a RAM, and may include multiple devices. The calculation unit includes, for example, a CPU or an MPU, and may include multiple devices. The interface transmits and receives signals between the inside of the controller 45 and external devices. Multiple interfaces may be provided depending on the type and number of external devices.

[0071] In the controller 45, for example, a calculation unit executes a program stored in a storage unit while referring to various information, thereby generating a signal for operating each part of the heating device 4. Examples of the various information include user input, signals from sensors provided in each part of the heating device 4, and data stored in the storage unit. The signal generated in the controller 45 is transmitted to a driver, which will be described later, through an interface, for example. In addition, the signal generated in the controller 45 may be transmitted to each part of the heating device 4 through an interface or the like.

[0072] For example, when a sensor detects that the work loading section 41 and the work unloading section 42 are closed and that the work W is in a predetermined position for performing the heating process, the controller 45 controls the pressure reducing device based on a signal from the sensor to reduce the pressure in the chamber 40.

[0073] Also, for example, if the chamber 40 is equipped with a pressure sensor, when the pressure sensor detects that the air pressure inside the chamber 40 has fallen below a predetermined value, the controller 45 generates and transmits a signal for causing the light-emitting element 44L described later to emit light based on the signal from the pressure sensor.

[0074] <Configuration of the irradiation unit> 5 is a schematic diagram showing an example of the configuration of the irradiation unit 44 of the heating device 4 according to the first embodiment of the present invention, viewed from the workpiece side in a direction perpendicular to the main surface of the workpiece. The irradiation unit 44 includes a plurality of light-emitting elements 44L, a first driver D1, a second driver D2, a third driver D3, and a fourth driver D4.

[0075] The light-emitting element 44L is provided on a surface of the irradiation unit 44 facing at least one of the main surfaces of the workpiece W. Here, the relationship of facing the main surface of the workpiece W includes a relationship of facing a plane that is an extension of the main surface of the workpiece W, even if it is on the outside of the workpiece W or on the hole H in a projection perpendicular to the main surface of the workpiece W. In addition, in the following description, the position of the light-emitting element 44L means the center position of the light-emitting portion of the light-emitting element 44L. This is the same for each embodiment and modified example described later. Note that FIG. 5 shows one of the irradiation units 44 shown in FIG. 4. In the following description, the irradiation unit 44 means one irradiation unit 44 unless otherwise specified, and the main surface of a pair of main surfaces of the workpiece W that faces the irradiation unit 44 is referred to as the "main surface of the workpiece W".

[0076] The light emitting element 44L is preferably, but not limited to, an LED. The light emitting elements 44L are preferably all spaced at equal distances from a plane including the main surface of the workpiece W. In this example, the light emitting elements 44L are mounted on a plane parallel to the main surface of the workpiece W.

[0077] The distance D of the light emitting element 44L from the plane including the main surface of the work W is the radius R of the outer periphery of the work W. W It is preferable that the light emitting element 44L is 2.0 times or less, more preferably 1.5 times or less, and further preferably 1.0 times or less, in order to efficiently irradiate the workpiece W with light relative to the amount of light emitted by the light emitting element 44L.

[0078] The distance D of the light emitting element 44L from the plane including the main surface of the work W is the radius R of the outer periphery of the work W. WIt is preferable that the light irradiation amount is 0.050 times or more, more preferably 0.10 times or more, and further preferably 0.20 times or more, in order to suppress unevenness in the amount of light irradiation on the surface of the workpiece W.

[0079] When the light emitting element 44L is a directional light source, the direction in which the light emission intensity is highest is preferably perpendicular to a plane including the main surface of the workpiece W. In this specification, when a configuration or position overlaps with a certain configuration or position in a projection in a direction perpendicular to the main surface of the workpiece W, these configurations or positions are considered to have a corresponding relationship.

[0080] In a projection in a direction perpendicular to the main surface of the workpiece W, the irradiation unit 44 preferably includes a light-emitting element 44L at a position corresponding to the end of the workpiece W and / or at a position corresponding to the outside of the workpiece W. This is to ensure that the end of the workpiece W is also sufficiently irradiated with light.

[0081] The surface of the irradiation unit 44 facing the main surface of the workpiece W includes a first area A1 including a position corresponding to the center of the workpiece W, a second area A2 surrounding the first area A1 from the outside, and a third area A3 surrounding the second area A2 from the outside and including a position corresponding to the outer periphery of the workpiece W, and the amount of light emitted per unit area in the third area A3 is greater than the amount of light emitted per unit area in the first area A1 and the amount of light emitted per unit area in the second area A2. This is because the outer peripheral end of the workpiece W is prone to heat loss and needs to be heated sufficiently. Here, the amount of light emitted per unit area in a certain area is a value obtained by dividing the total amount of light emitted by the light-emitting elements 44L arranged in that area by the area of ​​that area.

[0082] In addition to the above configuration, it is preferable that the amount of light emitted per unit area in the second region A2 is greater than the amount of light emitted per unit area in the first region A1.

[0083] Here, the amount of light emitted per unit area in the first region A1 is L1, the amount of light emitted per unit area in the second region A2 is L2, and the amount of light emitted per unit area in the third region A3 is L3.

[0084] L1 / L2 is preferably 0.70 or less, more preferably 0.50 or less, and even more preferably 0.30 or less. This is to suppress an excessive temperature rise in the portion close to the hole H of the workpiece W which is easily heated, and to suppress heating of components in the chamber 40, which will be described later, by the light passing through the hole H. Note that L1 / L2 may be 0. In other words, the light-emitting element 44L may not be provided in the first region A1.

[0085] L2 / L3 is preferably 0.80 or less, more preferably 0.60 or less, and even more preferably 0.40 or less. This is because heat is easily lost from the outer peripheral end of the workpiece W, and by increasing the amount of light emitted in the third area A3 compared to the second area A2, the vicinity of the outer periphery of the workpiece W is heated more efficiently. L2 / L3 is preferably 0.050 or more, more preferably 0.10 or more, and even more preferably 0.20 or more. This is to prevent the outside of the workpiece W from being excessively heated. The upper limit and lower limit values ​​of L2 / L3 can be combined arbitrarily. The same applies to combinations of upper limit values ​​and lower limit values ​​of other constituent elements in this specification.

[0086] To achieve this, for example, the number of light-emitting elements 44L provided per unit area in the third region A3 is made greater than the number of light-emitting elements 44L provided per unit area in the first region A1 and the number of light-emitting elements 44L provided per unit area in the second region A2.

[0087] To achieve this, for example, as shown in FIG. 5, the number of light-emitting elements 44L provided per unit area in the second region A2 is made greater than the number of light-emitting elements 44L provided per unit area in the first region A1.

[0088] The number of light-emitting elements 44L provided in the second area A2 is preferably 80 or more, more preferably 160 or more, and even more preferably 240 or more. This is to suppress unevenness in the amount of light irradiated onto the workpiece W.

[0089] The number of light emitting elements 44L provided in the third area A3 is preferably 240 or more, more preferably 480 or more, and even more preferably 720 or more. This is to suppress unevenness in the amount of light irradiated onto the workpiece W.

[0090] Here, the number of light-emitting elements 44L provided per unit area in each region is a value obtained by dividing the total number of light-emitting elements 44L provided in each region by the area of ​​each region. In addition, in Fig. 5, the light-emitting elements 44L are provided at equal intervals in each region, but this is not limited thereto and a pattern or the like may be formed.

[0091] The number of light-emitting elements 44L provided per unit area in the first region A1 is N1, the number of light-emitting elements 44L provided per unit area in the second region A2 is N2, and the number of light-emitting elements 44L provided per unit area in the third region A3 is N3.

[0092] N1 / N2 is preferably 0.70 or less, more preferably 0.50 or less, and even more preferably 0.30 or less. This is to suppress an excessive temperature rise in the portion close to the hole H of the workpiece W which is easily heated, and to suppress heating of components in the chamber 40, which will be described later, by the light passing through the hole H. Note that N1 / N2 may be 0. In other words, the light-emitting element 44L may not be provided in the first region A1.

[0093] N2 / N3 is preferably 0.80 or less, more preferably 0.60 or less, and even more preferably 0.40 or less. This is because heat is easily lost from the outer peripheral end of the workpiece W, and by increasing the amount of light emitted from the third area A3 compared to the second area A2, the vicinity of the outer periphery of the workpiece W is heated more efficiently. N2 / N3 is preferably 0.050 or more, more preferably 0.10 or more, and even more preferably 0.20 or more. This is to prevent the outside of the workpiece W from being heated excessively.

[0094] In the m-th region Am (where m is 2, 3, or other (for example, m is 21, 22, etc.; details will be described later)) other than the first region A1, the number of light-emitting elements 44L provided per unit area is N m (Unit: pcs / cm 2 ), then 1 / N m (Unit: cm 2 In this embodiment, the area that fits within the m-th region Am is 25 / N m In the circle, that is, 1 / N m It is preferable that at least one light emitting element 44L is present within a circle having an area 25 times that of the m-th region Am, and the area contained within the m-th region Am is 12 / N m It is more preferable that at least one light emitting element 44L is present in the circle, and the area contained in the m-th region Am is 8.0 / N m It is more preferable that at least one light emitting element 44L is present within the circle. This is to suppress unevenness in the amount of light irradiated onto the workpiece W.

[0095] In a vertical projection onto the main surface of the workpiece W, the outer periphery of the first region A1, the outer periphery of the second region A2, the outer periphery of the third region A3, the outer periphery of the workpiece W, and the shape of the hole H (the inner periphery of the workpiece W) are preferably concentric circles when viewed from a direction perpendicular to the main surface of the workpiece W. In the following description, unless otherwise specified, the lengths and shapes refer to the lengths and shapes in the vertical projection onto the main surface of the workpiece W.

[0096] The radius of the outer periphery of the first area A1 is R A1, the radius of the outer periphery of the second region A2 is R A2 , the radius of the periphery of the third area A3 is R A3 , the radius of the workpiece W is R W , the radius of the hole H is R H Then, the radius R of the outer periphery of the first area A1 is A1 is 0.50R H The radius R of the outer periphery of the first region A1 is preferably equal to or larger than the radius R of the outer periphery of the first region A1. A1 is 0.43R H +0.57R W It is preferable that the R is less than 0.56. H +0.44R W It is more preferable that the radius R of the outer periphery of the first region A1 is equal to or smaller than the radius R of the outer periphery of the first region A1. A1 is 0.70R H +0.30R W It is most preferable that:

[0097] In this case, the radius R of the outer periphery of the second region A2 A2 is 0.40R H +0.60R W It is preferable that the value is 0.33R or more. H +0.67R W It is more preferable that the radius R of the outer periphery of the second region A2 is equal to or larger than the radius R of the outer periphery of the second region A2. A2 is 0.03R H +0.97R W It is preferable that the R is less than 0.10. H +0.90R W It is more preferable that the radius R of the outer periphery of the second region A2 is equal to or smaller than the radius R of the outer periphery of the second region A2. A2 is 0.17R H +0.83R W It is most preferable that:

[0098] In this case, the radius R of the outer periphery of the third region A3 A3 is R W The radius R of the outer periphery of the third region A3 is preferably equal to or larger than the radius R of the outer periphery of the third region A3. A3 is 1.5R W It is preferable that the ratio is less than 1.3R. W It is more preferable that the radius R of the outer periphery of the second region A2 is equal to or smaller than the radius R of the outer periphery of the second region A2. A2 is 1.2R WIt is most preferable that:

[0099] The first driver D1, the second driver D2, the third driver D3, and the fourth driver D4 control the light emission of the light-emitting element 44L of each corresponding part in the irradiation unit 44 based on, for example, an instruction from the controller 45. That is, the controller 45 issues an instruction to each of the first driver D1, the second driver D2, the third driver D3, and the fourth driver D4 to control the light emission of the light-emitting element 44L. Here, when the first driver D1, the second driver D2, the third driver D3, and the fourth driver D4 are described without distinction, they may be referred to as drivers.

[0100] The controller 45 may perform control to select the light emitting element 44L to be caused to emit light in each of the first region A1, the second region A2, and the third region A3 from among the plurality of light emitting elements 44L. This makes it possible to adjust the amount of light emitted per unit area of ​​each of the first region A1, the second region A2, and the third region A3.

[0101] The controller 45 may control the amount of light emitted by the light-emitting element 44L in each of the first region A1, the second region A2, and the third region A3, thereby adjusting the amount of light emitted per unit area of ​​each of the first region A1, the second region A2, and the third region A3.

[0102] The light emission of the light-emitting element 44L is controlled by a current supplied from a driver. In this example, the driver is provided in the irradiation unit 44. However, this configuration is not limited, and the driver may be provided outside the irradiation unit 44, such as the controller 45.

[0103] In this example, the surface on which the light-emitting elements 44L of the irradiation unit 44 are mounted has four divided parts by two straight lines that pass through a position corresponding to the center of the workpiece W and are perpendicular to each other on the surface. If a set of multiple light-emitting elements 44L included in each divided part is considered as one control system, each of the first driver D1, the second driver D2, the third driver D3, and the fourth driver D4 collectively controls the light emission of the light-emitting elements 44L belonging to the corresponding system. The control system of the light-emitting elements 44L may be divided into three or less, or five or more. In addition, the division method does not require each part to have the same shape.

[0104] Also, the control systems corresponding to the drivers may be divided by a circle centered at a position corresponding to the center of the work W. Such a division method may be a division corresponding to the first area A1, the second area A2, and the third area A3 described above. This division method may be combined with the division method of Fig. 5. In this case, each part divided in Fig. 5 is further divided corresponding to the first area A1, the second area A2, and the third area A3, so that the number of control systems for the light emitting element 44L becomes 12 (the number of drivers is also 12).

[0105] <Modification of the configuration of the irradiation unit> Fig. 6 is a schematic diagram showing another example of the configuration of the irradiation unit 44 of the heating device 4 according to the first embodiment of the present invention, viewed from the workpiece W side in a direction perpendicular to the main surface of the workpiece W. In the following description, the description of the same configuration as that shown in Fig. 5 may be omitted. In addition, although a driver is not shown in Fig. 6, an example of the configuration of a driver applicable to this modified example will be described later with reference to Figs. 7 and 8.

[0106] In this example configuration, the light emitting elements 44L are disposed at equal intervals throughout the first region A1, the second region A2, and the third region A3. Note that, if an effect similar to that of this modified example can be obtained, the light emitting elements 44L do not need to be disposed at equal intervals.

[0107] Below, examples of a configuration for controlling the light emitting element 44L in this modified example will be described, but the invention is not limited to these examples.

[0108] Fig. 7 is a conceptual diagram showing an example of a configuration for controlling the irradiation unit 44 shown in Fig. 6. That is, in this diagram, the number and arrangement of the light-emitting elements 44L are merely conceptually shown as a concept of a control system, and do not match the actual number and arrangement of the light-emitting elements 44L. In this example, the light-emitting elements 44L in the first area A1 are composed of three sets of control systems, the light-emitting elements 44L in the second area A2 are composed of two sets of control systems, and the light-emitting elements in the third area A3 are composed of one set of control systems.

[0109] In this example, in the first region A1, the 1a driver D1a, the 1b driver D1b, and the 1c driver D1c each control the emission of a different light-emitting element 44L, in the second region A2, the 2a driver D2a and the 2b driver D2b each control the emission of a different light-emitting element 44L, and in the third region, the third driver D3 controls the emission of the light-emitting element 44L.

[0110] The control of the light emission amount of the light-emitting element 44L by each of the drivers D1a, D1b, D1c, D2a, D2b, and D3 is performed, for example, based on a command from the controller 45. That is, in this example, the controller 45 issues a command to control the light emission of the light-emitting element 44L corresponding to each of the drivers.

[0111] According to the configuration of this example, the light emitting elements 44L can be selectively made to emit light. Therefore, the number of light emitting elements 44L to be emitted per unit area in each region can be adjusted. In addition, by selectively using each control system in the region, the frequency of use of each light emitting element 44L is reduced, and the cost can be reduced by reducing the frequency of maintenance.

[0112] The number of control systems in each area is not limited to the number described here. Also, the light emitting element 44L provided in the third area A3 may be divided into two or more control systems.

[0113] In one preferred example, the light-emitting elements 44L in the first region A1 and the second region A2 are periodically arranged so that the nearest adjacent light-emitting elements 44L belong to different control systems, but this is not limiting. As another example, the light-emitting elements 44L controlled by the 2a driver D2a and the light-emitting elements 44L controlled by the 2b driver D2b may be arranged in a pattern.

[0114] In this control method, the number of light-emitting elements 44L that emit light per unit area in the third region A3 is greater than the number of light-emitting elements 44L that emit light per unit area in the first region A1 and the number of light-emitting elements 44L that emit light per unit area in the second region A2.

[0115] In this control method, more preferably, the number of light-emitting elements 44L that are caused to emit light per unit area in the second region A2 is greater than the number of light-emitting elements 44L that are caused to emit light per unit area in the first region A1.

[0116] The number of light-emitting elements 44L that emit light per unit area in the first region A1 is N1, the number of light-emitting elements 44L that emit light per unit area in the second region A2 is N2, and the number of light-emitting elements 44L that emit light per unit area in the third region A3 is N3.

[0117] N1 / N2 is preferably 0.70 or less, more preferably 0.50 or less, and even more preferably 0.30 or less. This is to suppress an excessive temperature rise in the portion close to the hole H of the workpiece W which is easily heated, and to suppress heating of components in the chamber 40 by light passing through the hole H. Note that N1 / N2 may be 0. In other words, the light-emitting element 44L does not need to be caused to emit light in the first region A1, and the light-emitting element 44L and a driver therefor may not be provided in the first region A1.

[0118] N2 / N3 is preferably 0.80 or less, more preferably 0.60 or less, and even more preferably 0.40 or less. This is because heat is easily lost from the outer peripheral end of the workpiece W, and by increasing the amount of light emitted from the third area A3 compared to the second area A2, the vicinity of the outer periphery of the workpiece W is heated more efficiently. N2 / N3 is preferably 0.050 or more, more preferably 0.10 or more, and even more preferably 0.20 or more. This is to prevent the outside of the workpiece W from being heated excessively.

[0119] In the m-th region Am (m is 2, 3, or other) other than the first region A1, the number of light-emitting elements 44L that emit light per unit area is set to N m Then, the area that fits within the mth region Am is 25 / N m It is preferable that at least one light emitting element 44L is caused to emit light within the circle, and the area contained within the m-th region Am is 12 / N m It is more preferable that at least one light emitting element 44L is made to emit light within the circle, and the area contained within the m-th region Am is 8.0 / N m It is more preferable that at least one light emitting element 44L is caused to emit light within the circle. This is to suppress unevenness in the amount of light irradiated onto the workpiece W.

[0120] Fig. 8 is a conceptual diagram showing another example of the configuration for controlling the irradiation unit 44 shown in Fig. 6. That is, in this diagram, the number and arrangement of the light-emitting elements 44L merely conceptually show the idea of ​​the control system, and do not match the number and arrangement of the actual light-emitting elements 44L.

[0121] As another example of a control method in the configuration shown in Fig. 8, the amount of light emitted per unit area in each region is adjusted by controlling the amount of light emitted by the light-emitting element 44L. Here, the amount of light emitted by the light-emitting element 44L is controlled by, for example, the magnitude of the current supplied to the light-emitting element 44L. Also, for example, a pulse wave current may be supplied to the light-emitting element 44L, and in this case, for example, it is preferable to control the amount of light emitted by the light-emitting element 44L by a duty ratio (PWM control). The method of controlling the amount of light emitted by the light-emitting element 44L is not limited to these, and other methods such as voltage, frequency, etc. may be used for control.

[0122] In this example, the first driver D1 controls the light emission amount of the light-emitting element 44L provided in the first area A1, the second driver D2 controls the light emission amount of the light-emitting element 44L provided in the second area A2, and the third driver D3 controls the light emission amount of the light-emitting element 44L provided in the third area A3. The control of the light emission amount of the light-emitting element 44L by each of the drivers D1, D2, and D3 is performed based on, for example, a command from the controller 45. That is, in this example, the controller 45 issues a command to adjust the light emission amount of the light-emitting element 44L in each of the first area A1, the second area A2, and the third area A3.

[0123] In this example, the light emission amount of each light-emitting element 44L increases in the order of the first region A1, the second region A2, and the third region A3. In this example, the light emission amount of each light-emitting element 44L in each region is a numerical average value obtained by dividing the total light emission amount in each region by the number of light-emitting elements 44L provided in each region. Also, in this example, the light emission amounts of the light-emitting elements 44L in each region may all be the same, or the light emission amounts of at least some of the light-emitting elements 44L may differ.

[0124] The amount of light emitted by each light-emitting element 44L in the first region A1 is I L1 The amount of light emitted by each light-emitting element 44L in the second region A2 is I L2 The light emission amount of each light-emitting element 44L in the third region A3 is I L3 Let us assume that.

[0125] I L1 / I L2 is preferably 0.70 or less, more preferably 0.50 or less, and even more preferably 0.30 or less. This is to prevent an excessive temperature rise in the portion close to the hole H of the work W which is easily heated, and to prevent the components in the chamber 40, which will be described later, from being heated by the light passing through the hole H. L1 / I L2 = 0. In other words, the light emitting element 44L does not have to emit light in the first region A1.

[0126] I L2 / I L3 is preferably 0.80 or less, more preferably 0.60 or less, and even more preferably 0.40 or less. This is because heat is easily lost from the outer peripheral end of the workpiece W, and it is necessary to make the amount of light emitted in the third area A3 greater than that in the second area A2. L2 / I L3 is preferably 0.050 or more, more preferably 0.10 or more, and even more preferably 0.20 or more, in order to suppress the temperature difference between the inside and outside of the workpiece W.

[0127] The heating device 4 in this embodiment has a disk shape with a hole H formed in the center, and is a heating device that heats the workpiece W by irradiating light onto the workpiece W having a pair of main surfaces facing each other. The heating device 4 has an irradiation unit 44 that faces at least one of the pair of main surfaces and irradiates light onto the workpiece W. The irradiation unit 44 has a plurality of light-emitting elements 44L on a surface facing the main surfaces of the workpiece W. The surface of the irradiation unit 44 facing the workpiece W includes a first region A1 including a position corresponding to the center of the workpiece W, a second region A2 that surrounds the first region A1 from the outside, and a third region A3 that surrounds the second region A2 from the outside and includes a position corresponding to the outer periphery of the workpiece W. The amount of light emitted per unit area in the third region A3 is greater than the amount of light emitted per unit area in the first region A1 and the amount of light emitted per unit area in the second region A2.

[0128] When the workpiece W is heated, heat is easily lost from the outer peripheral end of the workpiece W, and the temperature does not rise as easily near the outer periphery of the workpiece W compared to the inside. In contrast, according to the configuration of this embodiment, the amount of light emitted per unit area of ​​the third region A3 corresponding to the outside of the workpiece W is greater than the first region A1 and the second region A2, so it is possible to reduce the difference in temperature between the outer peripheral region of the workpiece W, from which heat is easily lost, and the temperature inside the workpiece W. Furthermore, in this configuration, the inside of the workpiece W does not need to be heated more than necessary, so it is possible to reduce the power used and reduce the occurrence of defective products due to excessive heating, leading to improved process productivity.

[0129] As described above, according to this embodiment, a heating device 4 can be provided that can heat the surface of a workpiece W having a disk shape with a hole formed in the center with high productivity and high uniformity.

[0130] Furthermore, in this embodiment, the amount of light emitted per unit area in the second area A2 can be greater than the amount of light emitted per unit area in the first area A1. By reducing the amount of light emitted in the first area A1 including the position corresponding to the center of the workpiece W, it is possible to prevent the heating device 4 itself from being heated by light passing through the hole H in the workpiece W in which the hole H is formed, which leads to protection of the heating device 4.

[0131] In addition, the manufacturing method of the magnetic recording medium 1 according to this embodiment includes a magnetic layer formation step S103 in which a magnetic layer 14 is formed on a workpiece W having a disk shape with a hole H formed in the center and a pair of main surfaces facing each other, and includes a heating step S104 in which the workpiece W is heated by irradiating light onto the workpiece W after the magnetic layer formation step S103. The heating step S104 is performed by irradiating light onto at least one of the main surfaces of the workpiece W by an irradiation unit 44 having a plurality of light-emitting elements 44L on a surface facing at least one of the pair of main surfaces of the workpiece W. The surface of the irradiation unit 44 facing the workpiece W includes a first region A1 including a position corresponding to the center of the workpiece W, a second region A2 surrounding the first region from the outside, and a third region A3 surrounding the second region from the outside and including a position corresponding to the outer periphery of the workpiece W. The amount of light emitted per unit area in the third region A3 is greater than the amount of light emitted per unit area in the first region A1 and the amount of light emitted per unit area in the second region A2.

[0132] According to this embodiment, it is possible to provide a manufacturing method for a magnetic recording medium 1 that can heat the surface of a disk-shaped workpiece W with a hole H formed in the center with high productivity and high uniformity. That is, according to this embodiment, it is possible to provide a manufacturing method for a magnetic recording medium 1 that can manufacture a disk-shaped magnetic recording medium 1 with a hole H formed in the center with high productivity and high quality.

[0133] [Second embodiment] FIG. 9 is a diagram showing an example of the distribution of the amount of light irradiated onto the main surface of the workpiece W by the irradiation unit 44 of the heating device 4 according to the second embodiment of the present invention. In this embodiment, the description may be omitted for configurations that may be the same as those of the above-mentioned embodiments. For example, in this embodiment, the configurations of the magnetic recording medium 1, the manufacturing method for the magnetic recording medium 1, the manufacturing device 3 for the magnetic recording medium 1, and the heating device 4 may be the same as those of the first embodiment. Also, in this embodiment, the configuration of the irradiation unit 44 may partially apply to the configuration of the irradiation unit 44 according to the first embodiment, and for example, the configuration of the irradiation unit 44 shown in FIG. 6 may be applied.

[0134] If a plane including the main surface of the workpiece W is the irradiated surface, the heating device 4 of this embodiment controls the amount of light irradiated onto the irradiated surface as described below.

[0135] The irradiated surface includes a first region W1, which is a region where the hole H of the workpiece W is formed, a second region W2 which surrounds the first region W1 from the outside, and a third region W3 which surrounds the second region W2 from the outside and extends from the outer periphery of the second region W2 to the outer periphery of the workpiece W. Here, the radius of the hole H is R H , the radius of the outer periphery of the workpiece W is R W The radius of the outer periphery of the second region W2 (the boundary between the second region and the third region) is 0.30R H +0.70R W , the radius of the periphery of the third region W3 is R W Let us assume that.

[0136] In this case, the average amount of light irradiation to the first region W1 is I1, the average amount of light irradiation to the second region W2 is I2, and the average amount of light irradiation to the third region W3 is I3. The average amount of light irradiation to each region is the total amount of light irradiation from the light-emitting element to each region on the irradiated surface divided by the area of ​​each region.

[0137] I1 / I2 is 1.00 or less, preferably 0.96 or less, and more preferably 0.94 or less. This is to suppress an excessive temperature rise in the portion of the workpiece W close to the hole H which is easily heated, and to suppress heating of components and the like in the chamber 40 by the light passing through the hole H. Moreover, I1 / I2 is preferably 0.85 or more, and more preferably 0.90 or more. This is to sufficiently heat the vicinity of the hole H of the workpiece W.

[0138] I3 / I2 is 1.50 or less, preferably 1.20 or less, and more preferably 1.00 or less. This is to suppress the amount of light irradiated from the outside of the workpiece W and more reliably protect the heating device 4. I3 / I2 is 0.90 or more, preferably 0.93 or more, and more preferably 0.96 or more. This is because heat is easily lost from the outer peripheral end of the workpiece W, and by increasing the amount of light irradiated to the third region W3 compared to the second region W2, the vicinity of the outer periphery of the workpiece W can be heated more efficiently.

[0139] The minimum value of the light irradiation intensity in each of the second region W2 and the third region W3 (within each region) is preferably 0.80 times or more, more preferably 0.85 times or more, and even more preferably 0.90 times or more of the average light irradiation amount in that region, in order to prevent localized insufficient heating of the workpiece W.

[0140] The maximum value of the light irradiation intensity in each of the second region W2 and the third region W3 is preferably 1.50 times or less, more preferably 1.30 times or less, and even more preferably 1.10 times or less of the average light irradiation amount in that region in order to prevent local overheating of the workpiece W.

[0141] Figure 9 illustrates the configuration of an area on one main surface of the workpiece W, but light may be irradiated onto both main surfaces of the workpiece W, in which case the configuration and shape of each area on both main surfaces may be the same (they are the same when projected in a direction perpendicular to the main surfaces) or they may be different.

[0142] 10 is a diagram showing a modified example of the distribution of the amount of light irradiated onto the main surface of the workpiece W by the irradiation unit 44 of the heating device 4 according to the second embodiment of the present invention. In this example, the second region W2 includes two regions: a 21st region W21 adjacent to the first region W1, and a 22nd region W22 located outside the 21st region W21.

[0143] Here, the outer periphery of the 21st region W21 is set to be intermediate between the inner periphery of the second region W2 (the outer periphery of the first region W1) and the outer periphery of the second region W2 (the inner periphery of the third region W3). W1 , the radius of the outer periphery of the second region W2 is R W2 Then, the radius R of the periphery of the 21st region W21 W21 is 0.50R W1 +0.50R W2 In other words, in the second region W2, from the center of the workpiece W, a radius of 0.50R W1 +0.50R W2 The circle and its interior are designated as the 21st region W21, and the area outside the circle is designated as the 22nd region.

[0144] In this case, the average amount of light irradiation in the 21st region W21 is I 21 , and the average light irradiation amount in the 22nd region W22 is I 22 Then, I 21 / I 22 is preferably 0.70 or more and 1.50 or less, more preferably 0.85 or more and 1.20 or less, and even more preferably 0.95 or more and 1.05 or less. This is to suppress uneven heating between the inside and outside of the workpiece W.

[0145] In addition, the definition of the average light irradiation amount in the modified example shown in Fig. 10 may be combined with the definition of the average light irradiation amount in the embodiment shown in Fig. 9. In this case, the radius R W2 is 0.30R H +0.70R W In the example shown in FIG. 9 and FIG. H =R W1 However, a hole H may be formed inside the first region W1 (R H <R W1 The first region W1 may be disposed inside the hole H (R H >R W1 (This is the state in which the

[0146] The heating device 4 according to the present embodiment is a heating device that heats the workpiece W by irradiating light onto the workpiece W having a pair of main surfaces facing each other and having a disk shape with a hole H formed in the center, and has an irradiation unit 44 that faces at least one of the pair of main surfaces of the workpiece W and irradiates light onto the workpiece W, and the irradiation unit 44 is provided with a plurality of light-emitting elements 44L on a surface facing the main surface of the workpiece W. If a plane including the main surface of the workpiece W is taken as an irradiated surface, the irradiated surface includes a first region W1 in which the hole H of the workpiece W is formed, a second region W2 that surrounds the first region W1 from the outside, and a third region W3 that extends from the outer periphery of the second region W2 to the outer periphery of the workpiece W, and the radius of the hole H is R. H , the radius of the outer periphery of the workpiece W is R W , the radius of the outer periphery of the second region W2 is 0.30R H +0.70R W , the radius of the periphery of the third region W3 is R W Let the average amount of light irradiated to the first region W1 be I1, the average amount of light irradiated to the second region W2 be I2, and the average amount of light irradiated to the third region W3 be I3, then I1 / I2 is 1.00 or less, and I3 / I2 is 0.90 or more and 1.50 or less.

[0147] When the workpiece W is heated, heat is easily lost from the outer peripheral end of the workpiece W, and the temperature is less likely to rise near the outer periphery of the workpiece W than the inside. In contrast, according to the heating device 4 of this embodiment, the average amount of light irradiated to the third region W3 corresponding to the outside of the workpiece W is set to a certain amount or more relative to the second region W2, that is, I3 / I2 is set to 0.90 or more. This configuration makes it possible to reduce the difference in temperature between the outer peripheral part of the workpiece W, from which heat is easily lost, and the inside temperature of the workpiece W. Furthermore, in this configuration, the inside of the workpiece W does not need to be heated more than necessary, so that the power used can be reduced and the occurrence of defective products due to excessive heating can be reduced, leading to improved process productivity. In addition, by setting I3 / I2 to 1.50 or less, excessive temperature rise near the outer peripheral end of the workpiece W can be suppressed.

[0148] Furthermore, by making I1 / I2 1.00 or less, i.e., by making the amount of light irradiated in the first region W1 including the center of the workpiece W less than that in the second region W2, it is possible to prevent the heating device 4 itself from being heated by light passing through the hole H in the workpiece W in which the hole H is formed, and thus it is possible to protect the heating device 4.

[0149] According to the manufacturing method of the magnetic recording medium 1 of the present embodiment, the manufacturing method includes a magnetic layer forming step S103 in which a magnetic layer 14 is formed on a workpiece W having a disk shape with a hole H formed in the center and a pair of main surfaces facing each other, and includes a heating step S104 in which the workpiece W is heated by irradiating light onto the workpiece W after the magnetic layer forming step S103. The heating step S104 is performed by irradiating light onto the main surface of the workpiece W by an irradiation unit having a plurality of light emitting elements on a surface facing at least one of the pair of main surfaces of the workpiece W. If a plane including at least one of the main surfaces of the workpiece W is taken as an irradiated surface, the irradiated surface includes a first region W1 in which the hole H of the workpiece W is formed, a second region W2 surrounding the first region W1 from the outside, and a third region W3 extending from the outside of the second region W2 to the outer circumferential end of the workpiece W, and the radius of the hole H is R. H , the radius of the outer periphery of the workpiece W is R W , the radius of the outer periphery of the second region W2 is 0.30R H +0.70R W , the radius of the periphery of the third region W3 is R W Let the average amount of light irradiated to the first region W1 be I1, the average amount of light irradiated to the second region W2 be I2, and the average amount of light irradiated to the third region W3 be I3, then I1 / I2 is 1.00 or less, and I3 / I2 is 0.90 or more and 1.50 or less.

[0150] According to the manufacturing method of the magnetic recording medium 1 of this embodiment, it is possible to reduce the difference in temperature between the outer periphery of the work W, where heat is easily lost, and the inside of the work W. Furthermore, in this configuration, it is not necessary to heat the inside of the work W more than necessary, so it is possible to reduce the amount of power used and reduce the occurrence of defective products due to excessive heating, which also leads to improved productivity of the process. In addition, it is possible to prevent the heating device 4 itself from being heated by the light passing through the hole H, and therefore the heating device 4 can be protected.

[0151] Although the embodiment has been described above, the above embodiment is presented as an example, and the present invention is not limited to the above embodiment. The above embodiment can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0152] 1 magnetic recording medium, W work, H hole, C carrier, 35 heating section, 4 heating device, 41 work loading section, 42 work unloading section, 43 work holding section, C carrier, 44 irradiation section, 44L light emitting element, 45 controller, 401 irradiation window, A1 first area (irradiation section), A2 second area (irradiation section), A3 third area (irradiation section), W1 first area (work), W2 second area (work), W21 second area (work), W22 second area (work), W3 third area (work)

Claims

1. A heating device that heats a workpiece by irradiating light onto the workpiece, the workpiece having a disk shape with a hole formed in the center and a pair of main surfaces facing each other, comprising: An irradiation unit that faces at least one of the pair of main surfaces and irradiates the workpiece with the light, The irradiation unit includes a plurality of light-emitting elements on a surface facing at least one of the main surfaces of the workpiece, The surface of the irradiation unit facing the workpiece includes a first region including a position corresponding to the center of the workpiece, a second region surrounding the first region from the outside, and a third region surrounding the second region from the outside and including a position corresponding to the outer periphery of the workpiece, A heating device, characterized in that the amount of light emitted per unit area in the third region is greater than the amount of light emitted per unit area in the first region and the amount of light emitted per unit area in the second region.

2. The heating device according to claim 1 , further comprising a pair of the irradiation units facing the pair of main surfaces of the workpiece, respectively.

3. the outer periphery of the first region, the outer periphery of the second region, the outer periphery of the workpiece, and the shape of the hole are concentric circles when viewed from a direction perpendicular to the main surface of the workpiece; The radius of the workpiece is R Ｗ , the radius of the hole is R Ｈ Then, The radius of the outer periphery of the first region is 0.50R Ｈ That's it, 0.43R Ｈ +0.57R Ｗ is as follows: The radius of the outer periphery of the second region is 0.40R Ｈ +0.60R Ｗ That's it, 0.03R Ｈ +0.97R Ｗ is as follows: The radius of the outer periphery of the third region is R Ｗ That's it, 1.5R Ｗ 2. The heating device according to claim 1, wherein:

4. The heating device according to claim 1 or 2, wherein the number of light-emitting elements provided per unit area in the third region is greater than the number of light-emitting elements provided per unit area in the first region and the number of light-emitting elements provided per unit area in the second region.

5. A controller for controlling the emission of the light emitting element, The heating device according to any one of claims 1 to 3, wherein the controller performs control to select the light-emitting elements to be caused to emit light from among the plurality of light-emitting elements in each of the first to third regions.

6. A controller for controlling the emission of the light emitting element, 4. The heating device according to claim 1, wherein the controller controls the amount of light emitted by the light-emitting elements in each of the first to third regions.

7. the controller issues a command to adjust the amount of light emitted by the light-emitting element in each of the first to third regions; a first driver that controls the amount of light emitted by the light-emitting element provided in the first region based on a command from the controller; a second driver that controls the amount of light emitted by the light-emitting element provided in the second region based on a command from the controller; The heating device according to claim 6 , further comprising: a third driver that controls an amount of light emitted by the light-emitting element provided in the third region based on a command from the controller.

8. 4. The heating device according to claim 1, wherein an amount of light emitted per unit area in the second region is greater than an amount of light emitted per unit area in the first region.

9. The amount of light emitted per unit area in the first region is L １ , the amount of light emitted per unit area in the second region is L ２ , the amount of light emitted per unit area in the third region L ３ Then, L １ / L ２ is 0.70 or less, and L ２ / L ３ The heating device according to claim 8 , wherein the ratio of the y-axis of the heating force to the y-axis of the

10. The heating device according to claim 8 , wherein the number of the light-emitting elements provided per unit area in the second region is greater than the number of the light-emitting elements provided per unit area in the first region.

11. The number of the light emitting elements provided per unit area in the first region is N １ The number of the light-emitting elements provided per unit area in the second region is N ２ The number of the light-emitting elements provided per unit area in the third region is N ３ Then, N １ / N ２ is 0.70 or less, and N ２ / N ３ The heating device according to claim 10, wherein is equal to or greater than 0.050 and equal to or less than 0.

80.

12. A controller for controlling the emission of the light emitting element, The heating device according to claim 8 , wherein the controller performs control to select the light emitting elements to be caused to emit light from among the plurality of light emitting elements in each of the first to third regions.

13. A controller for controlling the emission of the light emitting element, The heating device according to claim 8 , wherein the controller controls the amount of light emitted by the light-emitting elements in each of the first to third regions.

14. A method for manufacturing a magnetic recording medium, comprising the steps of: forming a magnetic layer on a workpiece having a disk shape with a hole formed in the center and a pair of main surfaces facing each other, the method comprising the steps of: A heating step of heating the workpiece by irradiating the workpiece with light after the magnetic layer forming step, The heating step is performed by irradiating light onto at least one of the pair of main surfaces of the workpiece using an irradiation unit having a plurality of light-emitting elements on a surface facing at least one of the pair of main surfaces of the workpiece, The surface of the irradiation unit facing the workpiece includes a first region including a position corresponding to the center of the workpiece, a second region surrounding the first region from the outside, and a third region surrounding the second region from the outside and including a position corresponding to the outer periphery of the workpiece, A method for manufacturing a magnetic recording medium, characterized in that the amount of light emitted per unit area in the third region is greater than the amount of light emitted per unit area in the first region and the amount of light emitted per unit area in the second region.

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