Heating device and method for manufacturing magnetic recording medium

Abstract

The purpose of the present invention is to provide a heating device capable of heating, with high productivity and high uniformity, the surface of a disc-shaped workpiece having a hole formed in the center thereof. A heating device that heats a workpiece by irradiating the workpiece with light includes an irradiation portion that faces at least one of a pair of main surfaces and irradiates the workpiece with the light, the irradiation portion including a plurality of light emitting elements on a surface facing the 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, the light emission amount per unit area in the third region is greater than the light emission amount per unit area in the first region and the light emission amount per unit area in the second region.

Description

Technical Field

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

[0002] Magnetic recording media are widely used as recording media for recording and storing various data. As a structure of a magnetic recording medium, for example, a magnetic layer is formed on a soft magnetic layer and a foundation layer formed on a substrate.

[0003] In order to meet the demand for increasing recording density, the miniaturization of the magnetic layer structure has been studied. In addition, in order to improve the recording quality, the magnetic layer uses a material that is resistant to thermal fluctuations, such as FePt alloy. When such a material is used, 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 records a film forming device, wherein one or more substrate holders for holding a substrate, a thin film material source, and a shielding component (shutter) arranged between the substrate holder and the thin film material source in a retractable manner are arranged in a film forming chamber, and one or more planar heaters for heating the substrate are arranged in the shielding component corresponding to the substrate.

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

[0006] Patent Document 1: Japanese Patent Application Publication No. 2002-129326

[0007] Patent Document 2: Japanese Patent Application Publication No. 2022-172776 Summary of the invention

[0008] <Problems to be Solved by the Invention>

[0009] There is a need to reduce the manufacturing cost of magnetic recording media. In addition, magnetic recording media having a disk shape with a hole formed in the center are widely used. Therefore, most of the workpieces in the manufacturing process also have the same shape.

[0010] Patent document 1 describes a structure in which a resistor such as pyrolytic graphite (PG) is formed in a predetermined pattern on an insulating substrate such as pyrolytic boron nitride (PBN) as a planar heater. The cost of this heater is very high, resulting in an increase in the manufacturing cost of the magnetic recording medium. In addition, it is difficult to control the distribution of the amount of heat within the surface. Therefore, defective products are sometimes produced due to overheating. In addition, when heating a workpiece with a hole formed in the center, the components in the device are easily heated due to the amount of infrared rays passing through the hole, and the process for protecting the device is cumbersome and the cost is also increased.

[0011] Patent Document 2 discloses a structure using LED elements as light emitting elements. However, during heating, heat escapes from the outer peripheral edge of the substrate, so in the configuration of the light emitting element disclosed in Patent Document 2, the temperature near the outer periphery of the substrate is lower than the inner side.

[0012] Therefore, an object of one embodiment of the present invention is to provide a heating device capable of heating the surface of a workpiece having a disk shape with a hole formed in the center thereof with high productivity and high uniformity.

[0013] <Methods used to solve problems>

[0014] In order to achieve the above object, the present invention has the following structure.

[0015] One embodiment of the present invention is a heating device, 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 portion and having a pair of main surfaces opposite to each other, wherein the heating device includes an irradiation portion that is opposite to at least one of the pair of main surfaces and irradiates the workpiece with the light, the irradiation portion having a plurality of light-emitting elements arranged on a surface opposite to at least one of the main surfaces of the workpiece, the surface of the irradiation portion opposite to the workpiece including: 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 periphery of the workpiece, the light emission per unit area of ​​the third region being greater than both the light emission per unit area of ​​the first region and the light emission per unit area of ​​the second region.

[0016] <Effects of the Invention>

[0017] According to one embodiment of the present invention, it is possible to provide a heating device capable of heating the surface of a workpiece having a disk shape with a hole formed in the center thereof with high productivity and high uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic cross-sectional view showing an example of the structure of a magnetic recording medium obtained by the method for producing a magnetic recording medium according to the first embodiment of the present invention.

[0019] Figure 2 This is a flowchart showing an example of a method for manufacturing a magnetic recording medium according to the first embodiment of the present invention.

[0020] Figure 3 This is a diagram schematically showing an example of a manufacturing apparatus for a magnetic recording medium according to the first embodiment of the present invention.

[0021] Figure 4 It is a schematic diagram in a plan view showing an example of the structure of the heating device according to the first embodiment of the present invention.

[0022] Figure 5 This is a schematic diagram of an example of the structure of the irradiation portion 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.

[0023] Figure 6 This is a schematic diagram of another example of the structure of the irradiation portion of the heating device according to the first embodiment of the present invention, viewed from the workpiece side in the direction perpendicular to the main surface of the workpiece.

[0024] Figure 7 It is used to control Figure 6 A conceptual diagram of an example of the structure of the irradiation unit shown.

[0025] Figure 8 It is used to control Figure 6 A conceptual diagram of another example of the structure of the irradiation unit shown.

[0026] Fig. 9 This is a diagram showing an example of the distribution of the irradiation amount of light irradiated onto the main surface of the workpiece by the irradiation section of the heating device according to the second embodiment of the present invention.

[0027] Fig.10 It is a diagram showing a modified example of the distribution of the irradiation amount of light irradiated onto the main surface of the workpiece by the irradiation section of the heating device according to the second embodiment of the present invention.

[0028] Description of Reference Numerals

[0029] 1 magnetic recording medium; W workpiece; H hole; C carrier; 35 heating section; 4 heating device; 41 workpiece carrying-in section; 42 workpiece carrying-out section; 43 workpiece 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 (workpiece); W2 second area (workpiece); W21 21st area (workpiece); W22 22nd area (workpiece); W3 third area (workpiece). DETAILED DESCRIPTION

[0030] Hereinafter, the mode for implementing the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the structure described below. It should be noted that the drawings used in the following description sometimes enlarge the features for convenience in order to facilitate understanding of the features, and the size ratios of the components are not necessarily the same as the actual ones.

[0031] The “workpiece” is a general term for the state of materials from the substrate 11 to the magnetic recording medium 1 described later, and both the state of the substrate 11 and the state of the magnetic recording medium 1 may be referred to as the workpiece.

[0032] [First embodiment]

[0033] <Structure of Magnetic Recording Medium>

[0034] Figure 1 1 is a schematic cross-sectional view showing an example of the layer structure of the magnetic recording medium obtained by the method for producing the magnetic recording medium according to the present embodiment. The magnetic recording medium described below is preferably applicable to a perpendicular magnetic recording system, but may also be applicable to other magnetic recording systems.

[0035] The magnetic recording medium 1 of this embodiment includes a substrate 11, and a soft magnetic layer 12, a foundation layer 13, a magnetic layer 14, and a protective layer 15 formed on the substrate 11 in order from the substrate 11 side. These layers may be formed on one main surface of the substrate 11 or on both main surfaces.

[0036] The structure of the magnetic recording medium 1 obtained by the manufacturing method of this embodiment is not limited to this structure, and layers other than the magnetic layer 14 and the foundation layer 13 may not be formed if not necessary, and layers other than the above-listed layers may be formed as needed.

[0037] It should be noted that in Figure 1 In the drawings, for convenience of explanation, the protective layer 15 may be referred to as an upper side or a surface side, and the substrate 11 may be referred to as a lower side or an inner side.

[0038] The shape of the substrate 11 is preferably a disk shape with a hole formed in the center. The material constituting the substrate 11 is preferably a non-magnetic material. The material constituting the substrate 11 may be an aluminum alloy, crystallized glass, amorphous glass, etc. In addition, the substrate 11 may be a structure in which a coating layer such as a plating layer is formed on a base material.

[0039] The soft magnetic layer 12 is provided on the substrate 11, and has the function of guiding the recording magnetic field from the magnetic head when a signal is recorded on the magnetic recording medium 1 and effectively applying the perpendicular component of the recording magnetic field to the magnetic layer 14. The material constituting the soft magnetic layer 12 may be a soft magnetic alloy such as FeCo alloy, CoZrNb alloy, and CoTaZr alloy.

[0040] The soft magnetic layer 12 preferably has an amorphous structure. This can improve the soft magnetic properties of the soft magnetic layer 12 and improve surface smoothness, thereby reducing the amount of magnetic head flying and further improving the recording density of the magnetic recording medium 1.

[0041] It should be noted that the soft magnetic layer 12 may be composed of one layer or may have a structure including multiple layers. When the soft magnetic layer 12 includes multiple layers forming an antiferromagnetic exchange coupling (AFC) film, a nonmagnetic layer such as a Ru film is preferably formed between the layers.

[0042] The total thickness of the soft magnetic layer 12 is appropriately determined according to the electromagnetic conversion characteristics of the magnetic recording medium 1 , but is preferably, for example, 20 nm to 120 nm.

[0043] The foundation layer 13 promotes the orientation of magnetic grains included in the magnetic layer 14. When the magnetic layer 14 includes magnetic grains having an L10 structure, the foundation layer 13 preferably enables the magnetic grains to be oriented to (001).

[0044] Examples of the material contained in the foundation layer 13 include NaCl type compounds, bcc alloys, etc. Examples of the NaCl type compounds include MgO. Examples of the bcc alloys include Cr alloys, W alloys, Mo alloys, and the like.

[0045] The base layer 13 may be composed of one layer or may have a structure including multiple layers. When the base layer 13 includes multiple layers, it is preferred, but not limited to, that the lower layer includes a bcc alloy and the uppermost layer includes a NaCl-based compound.

[0046] The magnetic layer 14 includes magnetic particles and is a layer for recording information. The magnetic particles preferably have an L10 structure. Examples of magnetic particles having an L10 structure include FePt alloy particles including FePt alloys, CoPt alloy particles including CoPt alloys, and the like. The magnetic layer 14 preferably has a granular structure.

[0047] The magnetic layer 14 may be composed of one layer or may have a structure including a plurality of layers. When the magnetic layer 14 includes a plurality of layers, each layer may be formed using the same type of material or using a different type of material. In addition, a non-magnetic layer may be included between each of the plurality of magnetic layers 14. The non-magnetic layer may be formed using a common material used in a magnetic recording medium.

[0048] The protective layer 15 prevents components such as a magnetic head from contacting the magnetic recording medium 1, thereby protecting the underlying layers such as the magnetic layer 14. The material forming the protective layer 15 is, for example, a carbon material such as diamond like carbon (DLC).

[0049] The magnetic recording medium 1 may include a lubricant layer (not shown) on the protective layer 15. The material forming the lubricant layer may be, for example, a resin such as perfluoropolyether.

[0050] <Method for Manufacturing Magnetic Recording Medium>

[0051] Figure 2 The flowchart shows an example of a method for manufacturing a magnetic recording medium 1 according to the first embodiment of the present invention. The method for manufacturing a magnetic recording medium 1 according to the present embodiment includes a soft magnetic layer forming step S101, a base layer forming step S102, a magnetic layer forming step S103, a heating step S104, and a protective layer forming step S105.

[0052] The manufacturing method of the magnetic recording medium 1 of the present embodiment may include other processes as needed. In addition, depending on the specifications of the magnetic recording medium, etc., the manufacturing method of the magnetic recording medium 1 of the present embodiment may not perform at least one of the processes other than the magnetic layer forming process S103 and the heating process S104. In addition, the treatment performed in the heating process S104 (described in detail later) may be performed after the process other than the magnetic layer forming process S103.

[0053] In the soft magnetic layer forming step S101, the soft magnetic layer 12 is formed on the main surface of the substrate 11. The structures of the substrate 11 and the soft magnetic layer 12 are as described above.

[0054] The method for forming the soft magnetic layer 12 may include DC (Direct Current) sputtering, etc., but is not limited to these methods. When the soft magnetic layer 12 includes a plurality of layers, the formation methods of the layers may be the same or different. In addition, 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.

[0055] In the foundation layer forming step S102, a foundation layer 13 is formed on the workpiece W on which the soft magnetic layer 12 is formed. The structure of the foundation layer 13 is as described above.

[0056] The formation method of the base layer 13 may include DC sputtering, etc., but is not limited to these methods. When the base layer 13 includes a plurality of layers, the method of forming each layer may be the same or different.

[0057] In the magnetic layer forming step S103 , the magnetic layer 14 is formed on the workpiece W having the foundation layer 13 formed thereon. The structure of the magnetic layer 14 is as described above.

[0058] The formation method of the magnetic layer 14 may include DC sputtering, etc., but is not limited to these methods. When the magnetic layer 14 includes a plurality of layers, the formation methods of the layers may be the same or different.

[0059] exist Figure 2In the example of FIG. 1 , the heating step S104 heats the workpiece W by irradiating light to the workpiece W having the magnetic layer 14 formed thereon. The heating step S104 improves 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 needed.

[0060] When forming a plurality of layers as the magnetic layer 14, it is preferable to perform the heating treatment according to the method performed in the heating step S104 after forming at least one layer, and it is preferable to perform the heating treatment after forming at least the layer on the lowermost side. In addition, the heating treatment according to the method performed in the heating step S104 may be performed each time one magnetic layer 14 is formed.

[0061] The protective layer forming step S105 forms a protective layer 15 on the workpiece W after the heating step S104. The structure of the protective layer 15 is as described above. The method of forming the protective layer 15 may include but is not limited to chemical vapor deposition (CVD) and the like.

[0062] The workpiece W on which the protective layer 15 has been formed may be further subjected to surface treatment, such as forming a lubricating layer or performing other treatments.

[0063] <Magnetic Recording Medium Manufacturing Apparatus>

[0064] Figure 3 1 is a diagram schematically showing an example of a manufacturing device for a magnetic recording medium 1 according to a first embodiment of the present invention. The manufacturing device 3 for a magnetic recording medium 1 according to the present embodiment (hereinafter also referred to as the manufacturing device 3) includes a workpiece input portion 31, a soft magnetic layer forming portion 32, a base layer forming portion 33, a magnetic layer forming portion 34, a heating portion 35, a protective layer forming portion 36, and a workpiece removal portion 37.

[0065] The manufacturing apparatus 3 of this example is an in-line manufacturing apparatus in which all processes for processing the workpiece W are performed in a chamber. Figure 3 In the figure, the arrow indicates the direction in which the workpiece W moves in the manufacturing device 3. The workpiece input part 31, the soft magnetic layer forming part 32, the base layer forming part 33, the magnetic layer forming part 34, the heating part 35, the protective layer forming part 36 and the workpiece taking-out part 37 may each be provided with a chamber for performing film forming treatment on the workpiece W. In the manufacturing device 3, the workpiece W input from the workpiece input part 31 is held in a carrier C and is taken out from the workpiece taking-out part 37 to the outside of the manufacturing device 3 through each chamber of the manufacturing device 3. It should be noted that this structure is only an example, and the manufacturing device 3 of the magnetic recording medium 1 of the present embodiment is not limited to the in-line type.

[0066] The workpiece W of the present embodiment is in the shape of a disk with a hole H formed in the center. The hole H is preferably circular, and the center of the hole H and the center of the workpiece W are preferably coincident.

[0067] The radius of the workpiece W is preferably 25 mm or more, preferably 40 mm or more, and more preferably 45 mm or more. In addition, the radius of the workpiece W is preferably 80 mm or less, preferably 60 mm or less, and more preferably 50 mm or less.

[0068] The radius of the hole H is preferably 6.0 mm or more, preferably 8.0 mm or more, and more preferably 10 mm or more. The radius of the hole H is preferably 20 mm or less, preferably 17 mm or less, and more preferably 14 mm or less.

[0069] The workpiece input part 31 has an opening and closing mechanism, and the opening and closing mechanism is opened when the workpiece W (substrate 11) is input into the manufacturing apparatus 3. As an example of a specific structure of the workpiece input part 31, a structure including a loading chamber (not shown) can be cited.

[0070] When the workpiece W is put in, the loading chamber is opened in a communicable manner relative to the outside of the manufacturing device 3. After the workpiece W is put into the loading chamber, the inside of the loading chamber is closed and decompressed. The decompression is performed, for example, by a decompression device such as a pump. When the pressure in the loading chamber is sufficiently low, in the example of the figure, the loading chamber is opened in a communicable manner relative to the inside of the manufacturing device 3 (that is, the soft magnetic layer forming section 32), and the workpiece W is transferred to the soft magnetic layer forming section 32.

[0071] This structure maintains the decompression state inside the manufacturing device 3. The structure and operation of the workpiece input part 31 described here are only an example and are not limited thereto. In addition, in order to further improve the airtightness inside the manufacturing device 3, the workpiece input part 31 may include a plurality of chambers connected in series, such as a loading chamber and a loading sub-chamber.

[0072] The soft magnetic layer forming step S101 is performed in the soft magnetic layer forming section 32 , the foundation layer forming step S102 is performed in the foundation layer forming section 33 , and the magnetic layer forming step S103 is performed in the magnetic layer forming section 34 .

[0073] The soft magnetic layer forming part 32, the base layer forming part 33, and the magnetic layer forming part 34 may be a structure in which only one layer is formed, or a structure in which more than two layers are formed. The lamination process of each layer in the soft magnetic layer forming part 32, the base layer forming part 33, and the magnetic layer forming part 34 is preferably performed in a chamber. For the parts in which multiple layers are formed in these parts, the formation of each layer is preferably performed in a different chamber. That is, each part preferably has a number of chambers corresponding to the number of layers formed there. Each chamber may independently include a decompression device. The decompression device may include a pump, etc., but is not particularly limited.

[0074] In the heating unit 35, a heating step S104 is performed. The heating step S104 is as described above. The heating unit 35 includes a heating device. The structure of the heating device will be described in detail later.

[0075] The protective layer forming unit 36 ​​performs the protective layer forming step S105. The protective layer forming step S105 is as described above. The lamination process in the protective layer forming unit 36 ​​is preferably performed in a cavity. In the case of forming a plurality of layers as the protective layer 15, each layer is preferably formed in a different cavity. That is, the protective layer forming unit 36 ​​preferably has a number of chambers corresponding to the number of layers formed thereon. Each chamber may independently include a decompression device. The decompression device may include a pump, etc., but is not particularly limited.

[0076] The workpiece taking-out portion 37 has an opening and closing mechanism, and the opening and closing mechanism is opened when the workpiece W is taken out from the manufacturing device 3. As an example of a specific structure of the workpiece taking-out portion 37, a structure including an unloading chamber (not shown) can be cited.

[0077] When the workpiece W is transferred from the protective layer forming part 36 to the workpiece taking-out part 37, the unloading chamber is opened. When the workpiece W is transferred to the unloading chamber, the opening and closing mechanism between the unloading chamber and the protective layer forming part 36 is closed, and then the pressure in the unloading chamber is increased. When the pressure in the unloading chamber is sufficiently increased, the unloading chamber can be communicated with the outside, and the workpiece W is taken out from the manufacturing device 3. The pressure in the unloading chamber is not limited when it is possible to communicate with the outside, but it is preferably increased to atmospheric pressure.

[0078] <Heating device>

[0079] Figure 4 1 is a schematic diagram showing an example of a structure of a heating device according to a first embodiment of the present invention when viewed from above. The heating device 4 of this embodiment heats a workpiece W by irradiating the workpiece W with light. The workpiece W has a disk shape with a hole formed in the center and has a pair of main surfaces facing each other. Figure 3 In one example, the heating device 4 is included in the heating section 35. Although the heating device 4 is an example of a device for implementing the above-mentioned heating method (heating step), the heating device 4 and the above-mentioned heating method do not necessarily have a corresponding relationship.

[0080] Figure 4 The heating device 4 of the example shown includes a chamber 40, a workpiece loading unit 41, a workpiece unloading unit 42, a workpiece holding unit 43, an irradiation unit 44, and a controller 45. It should be noted that the structure described below is only an example, and the heating device 4 of this embodiment is not limited to this structure.

[0081] When heating the workpiece W, the chamber 40 is preferably maintained in a reduced pressure state below atmospheric pressure. The chamber 40 is connected to a decompression device (not shown). The decompression device includes a pump, etc. It should be noted that this structure is only an example, and the chamber 40 may not be connected to the decompression device when heating is not required in a reduced pressure environment, when the entire path of the workpiece W of the manufacturing device 3 of the magnetic recording medium 1 is generally decompressed, etc.

[0082] The gas pressure in the chamber 40 in the reduced pressure state is not limited, but is preferably 10 Pa or less. This is to suppress heat loss due to heating of the gas in the chamber 40. In addition, this is to suppress the wall of the chamber 40 and the components in the chamber 40 from being heated by the heat conduction of the gas in the chamber 40. In addition, this is to suppress the increase in the gas pressure in the front and rear chambers when the workpiece W moves when the front and rear chambers are kept in the reduced pressure state.

[0083] The chamber 40 has an irradiation window 401 between the irradiation section 44 and the workpiece W, and the irradiation window 401 is a part of a partition that separates the inside and the outside of the chamber 40. That is, in the structure of this example, the workpiece W is inside the chamber 40, and the irradiation section 44 is outside the chamber 40. The irradiation window 401 transmits light from the irradiation section 44. The material of the irradiation window 401 is, for example, quartz.

[0084] According to this structure, it is possible to prevent pressure rise in the chamber 40 or contamination of the chamber 40 caused by gas or the like generated when the light emitting element 44L (described later in detail) provided in the irradiation portion 44 emits light.

[0085] The workpiece loading section 41 is opened when loading the workpiece W into the chamber 40, and is closed when loading of the workpiece W into the chamber 40 is completed. The workpiece unloading section 42 is closed during heating of the workpiece W, and is opened when unloading the workpiece W out of the chamber 40. That is, during the heating process of the workpiece W, the workpiece loading section 41 and the workpiece unloading section 42 are closed. During the heating process, in order to maintain a predetermined air pressure in the chamber 40, the pressure in the chamber 40 may be reduced by a decompression device or the like while the workpiece loading section 41 and the workpiece unloading section 42 are closed.

[0086] The workpiece holding portion 43 holds the workpiece W at a predetermined position so that the main surface of the workpiece W faces an irradiation portion 44 described later. Figure 4 In the illustrated structure, the workpiece holding portion 43 holds two workpieces W, but the number of workpieces W held by the workpiece holding portion 43 is not limited.

[0087] It should be noted that, in this example, as an example, the workpiece W is configured to move between each chamber while being held by the carrier C. That is, in this example, the carrier C corresponds to the workpiece holding portion 43. In the heating process, the carrier C stops at a position where the main surface of each workpiece W faces the corresponding irradiation portion 44.

[0088] The irradiation part 44 is opposite to at least one of a pair of main surfaces of the workpiece W, and irradiates the workpiece W with light. In this example, the irradiation parts 44 are respectively arranged in a pair opposite to a pair of main surfaces (two main surfaces) of the workpiece W, and have the same structure. Each irradiation part 44 irradiates the corresponding main surface (opposite main surface) of the workpiece W with light. However, this structure is only an example, for example, the irradiation part 44 can also be arranged only on one main surface side of the workpiece W. For example, in the case where the irradiation parts 44 are respectively arranged in a pair opposite to a pair of main surfaces of the workpiece W, the irradiation part 44 opposite to one main surface (front) of the workpiece W and the irradiation part 44 opposite to the other main surface (back) can have different structures. The structure of the irradiation part 44 will be described in detail later.

[0089] The controller 45 executes instructions for controlling the light emission (lighting and extinguishing) of the light emitting element 44L provided in the irradiation section 44, etc. The controller 45 includes a storage section, a calculation section, and an interface, which are not shown in the figure. The controller 45 may include other configurations.

[0090] The storage unit may include, for example, a ROM or a RAM, or may include multiple devices. The computing unit may include, for example, a CPU or an MPU, or may include multiple devices. The interface transmits signals between the internal and external devices of the controller 45. Depending on the type and number of external devices, multiple interfaces may be provided.

[0091] In the controller 45, for example, the operation unit executes the program stored in the storage unit while referring to various information, thereby generating a signal for operating each part of the heating device 4. The various information includes, for example, 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 sent to a driver described later, for example, through an interface. In addition, the signal generated in the controller 45 can also be sent to each part of the heating device 4 through an interface or the like.

[0092] For example, when the sensor detects that the workpiece loading unit 41 and the workpiece unloading unit 42 are closed and the workpiece W is located at a predetermined position for the heating process, the controller 45 controls the decompression device based on the signal from the sensor to decompress the chamber 40 .

[0093] In addition, for example, when the chamber 40 is provided with a pressure sensor, when the pressure sensor detects that the air pressure in the chamber 40 is lower than a predetermined value, the controller 45 generates and sends a signal for making the light emitting element 44L emit light based on the signal from the pressure sensor, which will be described later.

[0094] <Structure of irradiation unit>

[0095] Figure 5 1 is a schematic diagram showing an example of the structure of the irradiation unit 44 of the heating device 4 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. 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.

[0096] The light emitting element 44L is disposed on a surface of the irradiation portion 44 that is opposite to at least one main surface of the workpiece W. Here, the relationship relative to the main surface of the workpiece W also includes the relationship relative to the planes on the outside of the workpiece W or the hole H that are extensions of the main surface of the workpiece W in the projection in the direction 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 also the same for each embodiment and modified example described later. It should be noted that in Figure 5 In the Figure 4 In the following description, the irradiation portion 44 refers to one irradiation portion 44 unless otherwise specified. The main surface of the pair of main surfaces of the workpiece W, which is opposite to the irradiation portion 44, is referred to as the "main surface of the workpiece W".

[0097] The light emitting element 44L is preferably an LED, but is not limited thereto. Preferably, the light emitting element 44L is equidistant from a plane including the main surface of the workpiece W. In this example, the light emitting element 44L is mounted on a plane parallel to the main surface of the workpiece W.

[0098] The distance D between the light emitting element 44L and the plane including the main surface of the workpiece W is preferably equal to the outer radius R of the workpiece W. W The workpiece W is irradiated with light efficiently with respect to the light emission amount of the light emitting element 44L.

[0099] The distance D between the light emitting element 44L and the plane including the main surface of the workpiece W is preferably equal to the outer radius R of the workpiece W. W The amount of light irradiation on the surface of the workpiece W is preferably 0.050 times or more, more preferably 0.10 times or more, and further preferably 0.20 times or more. This is to suppress the unevenness of the amount of light irradiation on the surface of the workpiece W.

[0100] When the light emitting element 44L is a directional light source, the direction of the highest light intensity is preferably orthogonal to the plane including the main surface of the workpiece W. In this specification, regarding a structure or position overlapping with a certain structure or position in the projection in the direction perpendicular to the main surface of the workpiece W, it is assumed that these structures or positions have a corresponding relationship.

[0101] The irradiation unit 44 preferably includes a light emitting element 44L at least one of a position corresponding to the end of the workpiece W and a position corresponding to the outside of the workpiece W in projection in a direction perpendicular to the main surface of the workpiece W. This is to sufficiently irradiate the end of the workpiece W with light.

[0102] The surface of the irradiation portion 44 opposite to the main surface of the workpiece W includes: a first area A1, which includes a position corresponding to the center of the workpiece W; a second area A2, which surrounds the first area A1 from the outside; and a third area A3, which includes a position corresponding to the periphery of the workpiece W, wherein 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 peripheral end of the workpiece W is easy to dissipate heat and needs to be fully heated. Here, the amount of light emitted per unit area in a region refers to the value obtained by dividing the total amount of light emitted by the light-emitting elements 44L arranged in the region by the area of ​​the region.

[0103] In addition to the above structure, preferably, the light emission amount per unit area in the second area A2 is greater than the light emission amount per unit area in the first area A1.

[0104] Here, it is assumed that 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.

[0105] L1 / L2 is preferably 0.70 or less, more preferably 0.50 or less, and even more preferably 0.30 or less. This is because the portion of the workpiece W near the hole H is easily heated, so it is necessary to suppress the excessive temperature rise of this portion, and to suppress the components in the chamber 40 described later from being heated by the light passing through the hole H. It should be noted that L1 / L2=0 may also be possible. That is, the first area A1 may not include the light emitting element 44L.

[0106] L2 / L3 is preferably less than 0.80, more preferably less than 0.60, and further more preferably less than 0.40. This is because the peripheral end of the workpiece W is easy to dissipate heat, and by making the light emission of the third area A3 greater than the light emission of the second area A2, the periphery of the workpiece W is heated more efficiently. L2 / L3 is preferably greater than 0.050, more preferably greater than 0.10, and further more preferably greater than 0.20. This is to prevent the outer side of the workpiece W from being overheated. It should be noted that the upper limit and lower limit of L2 / L3 can be arbitrarily combined. In this specification, the same applies to the combination of upper limit and lower limit values ​​between other structural elements.

[0107] Therefore, for example, the number of light emitting elements 44L provided per unit area in the third area A3 is made larger than the number of light emitting elements 44L provided per unit area in the first area A1 and the number of light emitting elements 44L provided per unit area in the second area A2.

[0108] So, for example, Figure 5 As shown, the number of light emitting elements 44L provided per unit area in the second area A2 is made larger than the number of light emitting elements 44L provided per unit area in the first area A1.

[0109] 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 the variation in the amount of light irradiated to the workpiece W.

[0110] 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 the variation in the amount of light irradiated to the workpiece W.

[0111] 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. Figure 5 In the embodiment, the light emitting elements 44L are arranged at equal intervals in each region, but the present invention is not limited to this and a pattern or the like may be formed.

[0112] Assume that the number of light emitting elements 44L per unit area in the first region A1 is N1, the number of light emitting elements 44L per unit area in the second region A2 is N2, and the number of light emitting elements 44L per unit area in the third region A3 is N3.

[0113] N1 / N2 is preferably 0.70 or less, more preferably 0.50 or less, and even more preferably 0.30 or less. This is because the portion of the workpiece W near the hole H is easily heated, so it is necessary to suppress the excessive temperature rise of this portion, and to suppress the components in the chamber 40 described later from being heated by the light passing through the hole H. It should be noted that N1 / N2 may also be 0. That is, the light emitting element 44L may not be provided in the first area A1.

[0114] 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 the outer peripheral end of the workpiece W is easy to dissipate heat, and by making the light emission of the third area A3 greater than that of the second area A2, the 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 outer side of the workpiece W from being excessively heated.

[0115] In the m-th region Am (m represents 2, 3 or others (for example, m is 21 and 22, etc., the details will be described later)) other than the first region A1, if the number of light emitting elements 44L per unit area is set to N m (Unit: pieces / cm 2 ), then 1 / N m (Unit: cm 2 / pcs) represents the occupied area of ​​each light emitting element 44L. However, in this embodiment, it is preferred that the area accommodated in the mth region Am is 25 / N m of the circle (i.e., 1 / N m There is at least one light emitting element 44L in a circle with an area 25 times that of the mth region Am, and more preferably in a circle with an area 12 / N m There is at least one light emitting element 44L in the circle, and more preferably, the area contained in the mth region Am is 8.0 / N m There is at least one light emitting element 44L in the circle. This is to suppress the unevenness of the amount of light irradiated to the workpiece W.

[0116] In the projection in the direction perpendicular to the main surface of the workpiece W, when viewed from the direction perpendicular to the main surface of the workpiece W, the outer periphery of the first area A1, the outer periphery of the second area A2, the outer periphery of the third area 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. In the following description, the length and shape refer to the length and shape in the projection in the direction perpendicular to the main surface of the workpiece W unless otherwise specified.

[0117] If the radius of the outer circumference of the first area A1 is R A1 The radius of the outer periphery of the second area A2 is R A2The radius of the outer periphery of the third area A3 is R A3 , the radius of the workpiece W is R W , the radius of hole H is R H , then the radius R of the outer periphery of the first area A1 is A1 Preferably 0.50R H The radius R of the outer periphery of the first area A1 is A1 Preferably 0.43R H +0.57R W Below, more preferably 0.56R H +0.44R W The radius R of the outer periphery of the first area A1 is A1 Preferably 0.70R H +0.30R W .

[0118] In this case, the radius R of the outer periphery of the second area A2 is A2 Preferably 0.40R H +0.60R W More preferably 0.33R H +0.67R W The radius R of the outer periphery of the second area A2 is A2 Preferably 0.03R H +0.97R W Below, more preferably 0.10R H +0.90R W The radius R of the outer periphery of the second area A2 is A2 Preferably 0.17R H +0.83R W .

[0119] In this case, the radius R of the outer periphery of the third area A3 is A3 Preferably R W The radius R of the outer periphery of the third area A3 is A3 Preferably 1.5R W Below, more preferably 1.3R W The radius R of the outer periphery of the second area A2 is A2 Preferably 1.2R W .

[0120] For example, the first driver D1, the second driver D2, the third driver D3, and the fourth driver D4 control the light emission of the corresponding light emitting element 44L in each portion of the irradiation section 44 based on the command from the controller 45. That is, the controller 45 issues a command for controlling the light emission of the light emitting element 44L to each of the first driver D1, the second driver D2, the third driver D3, and the fourth driver D4. Here, when the first driver D1, the second driver D2, the third driver D3, and the fourth driver D4 are described without distinction, they are sometimes also referred to as drivers.

[0121] The controller 45 can perform control to select the light emitting element 44L to emit light from among the plurality of light emitting elements 44L in each of the first area A1, the second area A2, and the third area A3. Thus, the light emission per unit area of ​​each of the first area A1, the second area A2, and the third area A3 can be adjusted.

[0122] The controller 45 can control the light emission of the light emitting element 44L in each of the first area A1, the second area A2, and the third area A3. Thus, the light emission per unit area of ​​each of the first area A1, the second area A2, and the third area A3 can be adjusted.

[0123] The light emission of the light emitting element 44L is controlled by the current supplied from the driver. In this example, the driver is provided on the irradiation unit 44. It should be noted that the configuration is not limited to this, and the driver may be provided outside the irradiation unit 44 such as the controller 45.

[0124] In this example, the surface of the irradiation section 44 on which the light emitting element 44L is mounted has four parts, and the four parts are divided by two straight lines that are orthogonal to each other on the surface and pass through the position corresponding to the center of the workpiece W. When the group of multiple light emitting elements 44L included in each divided part is set as one control system, each of the first driver D1, the second driver D2, the third driver D3 and the fourth driver D4 uniformly controls the light emission of the light emitting element 44L belonging to the corresponding system. The control system of the light emitting element 44L can be divided into three or less, or can be divided into five or more. In addition, regarding the division method, the parts may not have the same shape.

[0125] In addition, the control system corresponding to each driver can be divided by a circle centered at a position corresponding to the center of the workpiece W. As such a division method, there is a division method corresponding to the first area A1, the second area A2, and the third area A3 described above. In addition, this division method can also be used in conjunction with Figure 5 In this case, Figure 5The divided parts are further divided corresponding to the first area A1, the second area A2 and the third area A3, so the control system of the light emitting element 44L is 12 (the number of drivers is also 12).

[0126] <Modification of the structure of the irradiation unit>

[0127] Figure 6 FIG. 4 is a schematic diagram showing another example of the structure of the irradiation portion 44 of the heating device 4 according to the first embodiment of the present invention as viewed from the workpiece W side in a direction perpendicular to the main surface of the workpiece W. Figure 5 In addition, although the structure is similar to the structure shown in the description Figure 6 The driver is not shown here, but will be referenced later. Figure 7 and Figure 8 An example of the structure of a driver applicable to this modification is described.

[0128] In the structure according to this example, the light emitting elements 44L are arranged at equal intervals throughout the first area A1, the second area A2, and the third area A3. It should be noted that the light emitting elements 44L do not need to be arranged at equal intervals if the same effect as that according to this modification is obtained.

[0129] Hereinafter, examples of the configuration for controlling the light emitting element 44L according to this modification are described, but the present invention is not limited to these examples.

[0130] Figure 7 It is used to control Figure 6 1 is a conceptual diagram of an example of the structure of the irradiation unit 44 shown in FIG. That is, in this figure, the number and arrangement of the light emitting elements 44L only conceptually represent the concept of the control system, and do not correspond to the actual number and arrangement of the light emitting elements 44L. In this example, the light emitting elements 44L in the first area A1 include three control systems, the light emitting elements 44L in the second area A2 include two control systems, and the light emitting elements in the third area A3 include one control system.

[0131] In this example, in the first area A1, the 1a driver D1a, the 1b driver D1b and the 1c driver D1c respectively control the light emission of different light-emitting elements 44L, in the second area A2, the 2a driver D2a and the 2b driver D2b respectively control the light emission of different light-emitting elements 44L, and in the third area, the third driver D3 controls the light emission of the light-emitting element 44L.

[0132] For example, the control of the light emission amount of the light emitting element 44L by each driver D1a, D1b, D1c, D2a, D2b, D3 is performed based on the instruction from the controller 45. That is, in this example, the controller 45 issues an instruction for controlling the light emission of the light emitting element 44L corresponding to each of the above-mentioned drivers.

[0133] According to the structure of this example, the light emitting element 44L can be selectively made to emit light. Therefore, the number of light emitting elements 44L that emit light per unit area in each region can be adjusted. In addition, by selecting each control system in the region for use, the frequency of use of each light emitting element 44L becomes low, thereby reducing the cost by reducing the maintenance frequency.

[0134] It should be noted that the number of control systems in each area is not limited to the number described here. In addition, the light emitting element 44L included in the third area A3 may be divided into two or more control systems.

[0135] As a preferred example, the light emitting elements 44L that are closest to each other in the first area A1 and the second area A2 are periodically arranged to belong to different control systems, but the present invention is not limited thereto. As another example, the light emitting elements 44L controlled by the 2a-th driver D2a and the light emitting elements 44L controlled by the 2b-th driver D2b may be arranged in a pattern.

[0136] In this control method, the number of light emitting elements 44L emitting light per unit area in the third area A3 is greater than the number of light emitting elements 44L emitting light per unit area in the first area A1 and the number of light emitting elements 44L emitting light per unit area in the second area A2.

[0137] In this control method, it is preferable that the number of light emitting elements 44L emitting light per unit area in the second area A2 is greater than the number of light emitting elements 44L emitting light per unit area in the first area A1.

[0138] Assume that the number of light emitting elements 44L emitting light per unit area in the first area A1 is N1, the number of light emitting elements 44L emitting light per unit area in the second area A2 is N2, and the number of light emitting elements 44L emitting light per unit area in the third area A3 is N3.

[0139] N1 / N2 is preferably 0.70 or less, more preferably 0.50 or less, and even more preferably 0.30 or less. This is because the portion of the workpiece W near the hole H is easily heated, so it is necessary to suppress the excessive temperature rise of this portion, and to suppress the heating of the components in the chamber 40 by the light passing through the hole H. It should be noted that N1 / N2=0 may also be possible. That is, the light emitting element 44L does not need to emit light in the first area A1, and the light emitting element 44L and the driver for the light emitting element 44L may not be included in the first area A1.

[0140] 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 the outer peripheral end of the workpiece W is easy to dissipate heat, and by making the light emission of the third area A3 larger than the light emission of the second area A2, the 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 outer side of the workpiece W from being overheated.

[0141] In the m-th region Am (m represents 2, 3 or other) other than the first region A1, if the number of light emitting elements 44L to emit light per unit area is N m , it is preferred that at least one light emitting element 44L emit light in a circle with an area of ​​25 / Nm contained in the m-th region Am, and more preferably in a circle with an area of ​​12 / Nm contained in the m-th region Am. m At least one light emitting element 44L emits light in a circle of 8.0 / N, and more preferably, the area contained in the m-th region Am is 8.0 / N. m At least one light emitting element 44L emits light in the circle. This is to suppress the unevenness of the irradiation amount of light irradiated to the workpiece W.

[0142] Figure 8 It is used to control Figure 6 1 is a conceptual diagram of another example of the structure of the irradiation unit 44. That is, in this figure, the number and arrangement of the light emitting elements 44L only conceptually represent the concept of the control system and do not correspond to the actual number and arrangement of the light emitting elements 44L.

[0143] As Figure 8Another example of the control method in the structure shown is to adjust the light emission per unit area in each region by controlling the light emission of the light emitting element 44L. Here, the light emission of the light emitting element 44L is controlled, for example, by the magnitude of the current supplied to the light emitting element 44L. In addition, for example, a pulse wave current may be supplied to the light emitting element 44L. In this case, for example, it is preferable to control the light emission of the light emitting element 44L by a duty cycle (PWM control). The method for controlling the light emission of the light emitting element 44L is not limited to the above method, and may also be controlled by other methods such as voltage and frequency.

[0144] In this example, the first driver D1 controls the light emission of the light emitting element 44L provided in the first area A1, the second driver D2 controls the light emission of the light emitting element 44L provided in the second area A2, and the third driver D3 controls the light emission of the light emitting element 44L provided in the third area A3. The control of the light emission of the light emitting element 44L by each of the drivers D1, D2, and D3 is performed, for example, based on an instruction from the controller 45. That is, in this example, the controller 45 issues an instruction for adjusting the light emission of the light emitting element 44L in each of the first area A1, the second area A2, and the third area A3.

[0145] In this example, the light emission of each light emitting element 44L increases in the order of the first area A1, the second area A2, and the third area A3. In this example, the light emission of each light emitting element 44L in each area is an average value obtained by dividing the total light emission in each area by the number of light emitting elements 44L provided in each area. In addition, in this example, the light emission of the light emitting elements 44L in each area may be the same, or the light emission of at least some of the light emitting elements 44L may be different.

[0146] The light emission amount of each light emitting element 44L in the first area A1 is represented as I L1 , the light emission of each light emitting element 44L in the second area A2 is represented as I L2 , the light emission of each light emitting element 44L in the third area A3 is represented as I L3 .

[0147] I L1 / I L2 It is preferably 0.70 or less, more preferably 0.50 or less, and even more preferably 0.30 or less. This is because the portion of the workpiece W near the hole H is easily heated, so it is necessary to suppress the excessive temperature rise of this portion, and to suppress the components in the chamber 40 described later from being heated by the light passing through the hole H. It should be noted that it may also be I L1 / I L2 = 0. That is, the light emitting element 44L may not emit light in the first area A1.

[0148] I L2 / I L3 It is preferably 0.80 or less, more preferably 0.60 or less, and even more preferably 0.40 or less. This is because the outer peripheral end of the workpiece W is easy to dissipate heat, and the light emission of the third area A3 needs to be greater than that of the second area A2. L2 / I L3 It is preferably 0.050 or more, more preferably 0.10 or more, and even more preferably 0.20 or more. This is to suppress the temperature difference between the inside and the outside of the workpiece W.

[0149] The heating device 4 of the present embodiment is a heating device for heating the workpiece W by irradiating light to the workpiece W, wherein the workpiece W has a disk shape with a hole H formed in the center portion and has a pair of main surfaces opposite to each other, wherein the heating device 4 has an irradiation portion 44, the irradiation portion 44 is opposite to at least one of the pair of main surfaces, and irradiates light to the workpiece W, the irradiation portion 44 has a plurality of light-emitting elements 44L on the surface opposite to the main surface of the workpiece W, and the surface of the irradiation portion 44 opposite to the workpiece W includes: a first area A1, which includes a position corresponding to the center of the workpiece W; a second area A2, which surrounds the first area A1 from the outside; and a third area A3, which surrounds the second area A2 from the outside and includes a position corresponding to the 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.

[0150] When the workpiece W is heated, the outer peripheral end of the workpiece W is easy to dissipate heat, and the temperature near the outer periphery of the workpiece W is less likely to rise than the inner side. In contrast, according to the structure of this embodiment, the light emission per unit area of ​​the third area A3 corresponding to the outer side of the workpiece W is greater than that of the first area A1 and the second area A2, so the difference between the temperature of the outer peripheral part of the workpiece W that is easy to dissipate heat and the temperature of the inner side of the workpiece W can be reduced. Furthermore, in this structure, it is not necessary to heat the inner side of the workpiece W too much, so it is possible to reduce the power used and reduce the defective products caused by excessive heating, thereby improving the productivity of the process.

[0151] As described above, according to the present embodiment, it is possible to provide a heating device 4 capable of heating the surface of a disk-shaped workpiece W having a hole formed in the center thereof with high productivity and high uniformity.

[0152] Furthermore, in the present embodiment, the amount of light emitted per unit area in the second region A2 may be greater than the amount of light emitted per unit area in the first region A1. By reducing the amount of light emitted in the first region A1 including the position corresponding to the center portion of the workpiece W, in the workpiece W having the hole H formed therein, the heating device 4 itself can be prevented from being heated by the light of the portion passing through the hole H, thereby protecting the heating device 4.

[0153] Furthermore, in the manufacturing method of the magnetic recording medium 1 of the present embodiment, a magnetic layer forming step S103 is included for forming a magnetic layer 14 on a workpiece W having a disk shape with a hole H formed in the center and having a pair of main surfaces facing each other, and after the magnetic layer forming step S103, a heating step S104 is included for heating the workpiece W by irradiating light to the workpiece W, wherein the heating step S104 is performed by irradiating light to at least one of the pair of main surfaces of the workpiece W using an irradiation unit 44, and the irradiation unit 44 is in contact with the workpiece W. A plurality of light-emitting elements 44L are provided on a surface opposite to at least one main surface of the workpiece W, and the surface of the irradiation portion 44 opposite to the workpiece W includes: a first area A1, which includes a position corresponding to the center of the workpiece W; a second area A2, which surrounds the first area A1 from the outside; and a third area A3, which surrounds the second area A2 from the outside and includes a position corresponding to the 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.

[0154] According to the present embodiment, a method for manufacturing a magnetic recording medium 1 can be provided, which can heat the surface of a disk-shaped workpiece W having a hole H formed in the center with high productivity and high uniformity. That is, according to the present embodiment, a method for manufacturing a magnetic recording medium 1 can be provided, which can manufacture a disk-shaped magnetic recording medium 1 having a hole H formed in the center with high productivity and high quality.

[0155] [Second embodiment]

[0156] Fig. 9 This is a diagram showing an example of the distribution of the irradiation amount of light irradiated to 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 of the structure that may be the same as the above-mentioned embodiment may be omitted. For example, in this embodiment, the structure of the magnetic recording medium 1, the manufacturing method of the magnetic recording medium 1, the manufacturing device 3 of the magnetic recording medium 1, and the heating device 4 may be the same as the structure in the first embodiment. In addition, in this embodiment, the structure of the irradiation unit 44 may partially adopt the structure of the irradiation unit 44 of the first embodiment, for example, Figure 6 The structure of the irradiation unit 44 is shown.

[0157] Assuming that a plane including the main surface of the workpiece W is an irradiated surface, the heating device 4 of the present embodiment controls the irradiation amount of light irradiated to the irradiated surface as follows.

[0158] The irradiated surface includes: a first area W1, which is an area where the hole H of the workpiece W is formed; a second area W2, which surrounds the first area W1 from the outside; and a third area W3, which surrounds the second area W2 from the outside, from the outer periphery of the second area W2 to the outer periphery of the workpiece W. Here, the radius of the hole H is set to R H , the radius of the outer circumference of the workpiece W is set to R W The radius of the outer periphery of the second region W2 (the boundary between the second region and the third region) is set to 0.30R H +0.70R W The radius of the outer periphery of the third region W3 is set to R W .

[0159] At this time, the average irradiation amount of light irradiated to the first area W1 is set to I1, the average irradiation amount of light irradiated to the second area W2 is set to I2, and the average irradiation amount of light irradiated to the third area W3 is set to I3. It should be noted that the average irradiation amount of light in each area is the value obtained by dividing the total irradiation amount of light from the light-emitting element in each area of ​​the irradiated surface by the area of ​​each area.

[0160] I1 / I2 is 1.00 or less, preferably 0.96 or less, and more preferably 0.94 or less. This is because the portion of the workpiece W near the hole H is easily heated, so it is necessary to suppress the excessive temperature rise of this portion and suppress the heating of the components in the chamber 40 by the light passing through the hole H. In addition, 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.

[0161] I3 / I2 is preferably 1.50 or less, more preferably 1.20 or less, and even more preferably 1.00 or less. This is to suppress the amount of light escaping from the outside of the workpiece W and more reliably protect the heating device 4. I3 / I2 is preferably 0.90 or more, more preferably 0.93 or more, and even more preferably 0.96 or more. This is because the outer peripheral end of the workpiece W is easy to dissipate heat, and by making the amount of light irradiated to the third area W3 larger than that of the second area W2, the periphery of the workpiece W can be heated more efficiently.

[0162] The minimum value of the irradiation intensity of light in each of the second region W2 and the third region W3 (in 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 irradiation amount of light in the region. This is to suppress insufficient local heating of the workpiece W.

[0163] The maximum value of the irradiation intensity of light 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 irradiation intensity of light in the region. This is to suppress local overheating of the workpiece W.

[0164] Although Fig. 9 The middle figure shows the structure of an area on one main surface of the workpiece W, but light can also be irradiated onto the two main surfaces of the workpiece W. In this case, the structures and shapes of the areas on the two main surfaces can be consistent (consistent in the projection in the direction perpendicular to the main surface) or different.

[0165] Fig.10 This is a diagram showing a modified example of the distribution of the irradiation amount of light irradiated to 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 area W2 includes two areas: a 21st area W21 adjacent to the first area W1 and a 22nd area W22 located outside the 21st area W21.

[0166] Here, the outer periphery of the 21st region W21 is set to be the middle 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). That is, if the radius of the outer periphery of the first region W1 is set to R W1 The radius of the outer periphery of the second region W2 is set to R W2 , then the radius R of the outer periphery of the 21st region W21 is W21 Set to 0.50R W1 +0.50R W2 In other words, in the second area W2, the radius from the center of the workpiece W is 0.50R W1 +0.50R W2 The circle and its inner side are set as the 21st area W21, and the outer side of the circle is set as the 22nd area.

[0167] In this case, if the average irradiation amount of light in the 21st area W21 is I 21 The average irradiation amount of light in the 22nd area W22 is I 22 , then I 21 / I 22 It is preferably 0.70 to 1.50, more preferably 0.85 to 1.20, and even more preferably 0.95 to 1.05. This is to suppress the variation in heating conditions inside and outside the workpiece W.

[0168] It should be noted that it is also possible to use Fig.10 The average irradiation amount of light in the modified example shown is defined in the same manner as described above. Fig. 9In the embodiment shown in the figure, the average irradiation amount of light is determined by the combination of the prescribed values. In this case, the radius R of the outer periphery of the second region W2 is W2 0.30R H +0.70R W .exist Fig. 9 and Fig.10 In the example shown, although R H =R W1 , but the hole H may be formed inside the first region W1 (R H <R W1 The first region W1 may be provided inside the hole H (R H >R W1 status).

[0169] The heating device 4 of the present embodiment is a heating device that heats the workpiece W by irradiating light to the workpiece W having a disk shape with a hole H formed in the center and a pair of main surfaces facing each other. The heating device 4 includes an irradiation portion 44, which is opposite to at least one of the pair of main surfaces of the workpiece W and irradiates light to the workpiece W, wherein the irradiation portion 44 has a plurality of light-emitting elements 44L on the surface opposite to the main surface of the workpiece W. If the plane including the main surface of the workpiece W is set as the irradiated surface, the irradiated surface includes: a first area W1, in which the hole H of the workpiece W is formed; a second area W2, which surrounds the first area W1 from the outside; and a third area W3, which extends from the outer periphery of the second area W2 to the outer periphery of the workpiece W. If the radius of the hole H is set as R H , the radius of the outer circumference of the workpiece W is set to R W The radius of the outer periphery of the second region W2 is set to 0.30R H +0.70R W The radius of the outer periphery of the third region W3 is set to R W , the average irradiation amount of light irradiated to the first area W1 is set to I1, the average irradiation amount of light irradiated to the second area W2 is set to I2, and the average irradiation amount of light irradiated to the third area W3 is set to I3, then I1 / I2 is less than 1.00, and I3 / I2 is greater than 0.90 and less than 1.50.

[0170] When the workpiece W is heated, the outer peripheral end of the workpiece W is easy to dissipate heat, and the temperature near the outer periphery of the workpiece W is less likely to rise than the inner side. In contrast, according to the heating device 4 of this embodiment, the average irradiation amount of light irradiated to the third area W3 corresponding to the outer side of the workpiece W is made to be greater than a certain amount relative to the second area W2, that is, I3 / I2 is greater than 0.90. According to this structure, the difference between the temperature of the outer periphery of the workpiece W from which heat easily escapes and the temperature of the inner side of the workpiece W can be reduced. Furthermore, in this structure, since there is no need to heat the inner side of the workpiece W too much, the power used can be reduced and the defective products caused by excessive heating can be reduced, thereby improving the productivity of the process. It should be noted that by setting I3 / I2 to less than 1.50, the excessive temperature rise near the outer peripheral end of the workpiece W can be suppressed.

[0171] In addition, by making I1 / I2 less than 1.00, that is, the amount of light irradiation in the first area W1 including the center portion of the workpiece W is less than that in the second area W2, in the workpiece W having a hole H formed therein, it is possible to prevent the heating device 4 itself from being heated by the light passing through the hole H, thereby protecting the heating device 4.

[0172] The method for manufacturing the magnetic recording medium 1 according to the present embodiment includes a magnetic layer forming step S103 for forming a magnetic layer 14 on a workpiece W having a disk shape with a hole H formed in the center and having a pair of main surfaces facing each other, and after the magnetic layer forming step S103, a heating step S104 for heating the workpiece W by irradiating light to the workpiece W, wherein the heating step S104 is performed by irradiating light to at least one of the pair of main surfaces of the workpiece W using an irradiation unit, the irradiation unit having a plurality of light emitting elements on a surface opposite to at least one main surface of the workpiece W, and if a plane including the main surface of the workpiece W is set 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, which surrounds the first region W1 from the outside; and a third region W3, which extends from the outside of the second region W2 to the outer peripheral end of the workpiece W, and if the radius of the hole H is set as R H , the radius of the outer circumference of the workpiece W is set to R W The radius of the outer periphery of the second region W2 is set to 0.30R H +0.70R W The radius of the outer periphery of the third region W3 is set to R W , the average irradiation amount of light irradiated to the first area W1 is set to I1, the average irradiation amount of light irradiated to the second area W2 is set to I2, and the average irradiation amount of light irradiated to the third area W3 is set to I3, then I1 / I2 is less than 1.00, and I3 / I2 is greater than 0.90 and less than 1.50.

[0173] According to the manufacturing method of the magnetic recording medium 1 of the present embodiment, the difference between the temperature of the outer peripheral portion of the workpiece W from which heat easily escapes and the temperature of the inner side of the workpiece W can be reduced. Furthermore, in this structure, since it is not necessary to heat the inner side of the workpiece W too much, it is possible to reduce the power used and reduce the defective products caused by excessive heating, thereby improving the productivity of the process. It should be noted that it is possible to suppress the heating device 4 itself from being heated by the light passing through the portion of the hole H, thereby protecting the heating device 4.

[0174] As described above, the embodiments are described, but the embodiments are presented as examples and do not limit the present invention. The embodiments can be implemented in various other ways, and various combinations, omissions, substitutions, changes, etc. can be made without departing from the scope of the invention. These embodiments and their variations are included in the scope and spirit of the invention, and are included in the invention described in the claims and the scope equivalent thereto.

Claims

1. A heating device for heating a workpiece by irradiating light onto the workpiece, the workpiece having a disk shape with a hole formed in the center and having a pair of main surfaces facing each other, wherein: The heating device includes an irradiation portion, which is opposite to at least one of the pair of main surfaces and irradiates the light toward the workpiece. The irradiation unit is provided with a plurality of light emitting elements on a surface opposite to at least one of the main surfaces of the workpiece. The surface of the irradiation portion opposite to the workpiece includes: a first area including a position corresponding to the center of the workpiece; a second area surrounding the first area from the outside; and a third area surrounding the second area from the outside and including a position corresponding to the periphery of the workpiece, The light emission amount per unit area of ​​the third region is larger than both the light emission amount per unit area of ​​the first region and the light emission amount per unit area of ​​the second region.

2. The heating device according to claim 1, wherein: The heating device includes a pair of irradiation portions respectively facing each of the pair of main surfaces of the workpiece.

3. The heating device according to claim 1, wherein: When viewed from a direction perpendicular to the main surface of the workpiece, the outer periphery of the first region, the outer periphery of the second region, the outer periphery of the third region, the outer periphery of the workpiece, and the shape of the hole are concentric circles, If the radius of the workpiece is R W , the radius of the hole is R H ,but The radius of the outer periphery of the first region is 0.50R H Above and 0.43R H +0.57R W the following, The radius of the outer periphery of the second region is 0.40R H +0.60R W Above and 0.03R H +0.97R W the following, The radius of the outer periphery of the third region is R W Above and 1.5R W the following.

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

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

6. The heating device according to any one of claims 1 to 3, wherein: The heating device comprises: a controller for controlling the light emission of the light emitting element, The controller controls the light emission amount of the light emitting element in each of the first to third regions.

7. The heating device according to claim 6, wherein: The controller issues a command for adjusting the light emission amount of the light emitting element in each of the first to third areas, The heating device comprises: a first driver that controls the light emission amount of the light emitting element provided in the first area based on a command from the controller; a second driver that controls the light emission amount of the light emitting element provided in the second area based on a command from the controller; and The third driver controls the light emission amount of the light emitting element provided in the third area based on the command from the controller.

8. The heating device according to any one of claims 1 to 3, wherein: The amount of light emitted per unit area in the second region is greater than the amount of light emitted per unit area in the first region.

9. The heating device according to claim 8, wherein: If the amount of light emitted per unit area in the first region is L1, the amount of light emitted per unit area in the second region is L2, and the amount of light emitted per unit area in the third region is L3, then L1 / L2 is less than 0.70, and L2 / L3 is greater than 0.050 and less than 0.

80.

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

11. The heating device according to claim 10, wherein: If the number of the light-emitting elements per unit area in the first region is N1, the number of the light-emitting elements per unit area in the second region is N2, and the number of the light-emitting elements per unit area in the third region is N3, then N1 / N2 is less than 0.70, and N2 / N3 is greater than 0.050 and less than 0.

80.

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

13. The heating device according to claim 8, wherein: The heating device comprises: a controller for controlling the light emission of the light emitting element, The controller controls the light emission amount of the light emitting element in each of the first to third regions.

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

Images