Production apparatus for magnetic recording media, production method for magnetic recording media, burnishing apparatus

Abstract

The present invention provides a magnetic recording medium production apparatus, a magnetic recording medium production method, and a burnishing apparatus that enable early detection or prediction of defective products during the production of magnetic recording media, thereby improving the productivity of magnetic recording media. [Solution] A production apparatus for a magnetic recording medium 1, comprising: a film deposition apparatus that deposits at least a magnetic recording layer 112 and a protective layer 113 on a substrate 111 in that order; a lubricant application apparatus that applies a lubricant onto the protective layer 113 deposited by the film deposition apparatus to form a lubricating layer 12; and a burnishing apparatus that burns the surface of the lubricating layer 12 applied by the lubricating apparatus with an abrasive, further comprising: a collection unit that collects load amount data during burnishing; a storage unit that stores the collected load amount data; a calculation unit that performs calculations using the stored load amount data; and a setting unit that sets the manufacturing conditions of the film deposition apparatus or the lubricating apparatus based on the calculation results from the calculation unit.

Description

Technical Field

[0001] The present invention relates to a production apparatus for a magnetic recording medium, a production method for a magnetic recording medium, and a burnishing apparatus.

Background Art

[0002] In recent years, magnetic storage devices have been mounted on various products such as personal computers, video recorders, and data servers, and their importance has been increasing. A magnetic storage device is a device having a magnetic recording medium for storing electronic data by magnetic recording. For example, there is a hard disk drive (HDD).

[0003] A general magnetic recording medium is produced through a film forming process in which a base layer, an intermediate layer, a magnetic recording layer, and a protective layer are formed in this order on a non-magnetic substrate using a film forming apparatus, then a lubricant coating process in which a lubricating layer is applied to the surface of the protective layer using a lubricant coating apparatus, then a burnishing process in which the surface is polished using a burnishing apparatus to remove foreign substances and protrusions on the surface of the lubricating layer, and then an inspection process in which inspection is performed using an inspection apparatus.

[0004] Patent Document 1 discloses a tape burnishing apparatus used in the production of a magnetic recording medium.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As mentioned above, magnetic recording media are produced through a long process, so even if defective products are detected during the inspection process, there may be many defective products already present in the production line at that point. In conventional magnetic recording media production equipment with a burnishing device, even if defective products occur in the process prior to the burnishing process, the burnishing device polishes the surface of all lubricating layers that have been sent after completing the processes prior to the burnishing process. Therefore, in order to reduce the number of defective products generated in magnetic recording media production equipment, it is necessary to detect the occurrence of defective products as early as possible, predict the occurrence of defective products, and thereby manage the production equipment in an optimal state.

[0007] One aspect of the present invention aims to provide a magnetic recording medium production apparatus, a magnetic recording medium production method, and a burnishing apparatus that can detect the occurrence of defective products at an early stage or predict the occurrence of defective products during the production of magnetic recording media, thereby increasing the productivity of magnetic recording media. [Means for solving the problem]

[0008] One aspect of the present invention is a production apparatus for a magnetic recording medium, comprising: a film deposition apparatus for depositing at least a magnetic recording layer and a protective layer on a substrate in that order; a lubricant application apparatus for applying a lubricant to the protective layer deposited by the film deposition apparatus to form a lubricating layer; and a burnishing apparatus for burning the surface of the lubricating layer applied by the lubricant application apparatus with an abrasive, wherein the apparatus includes: a collection unit for collecting load amount data during the burnishing process; a storage unit for storing the collected load amount data; a calculation unit for performing calculations using the stored load amount data; and a setting unit for setting the manufacturing conditions of the film deposition apparatus or the lubricant application apparatus based on the calculation results from the calculation unit.

[0009] One aspect of the present invention is a production apparatus for a magnetic recording medium, comprising: a film deposition apparatus for depositing at least a magnetic recording layer and a protective layer on a substrate in that order; a lubricant application apparatus for applying a lubricant to the protective layer deposited by the film deposition apparatus to form a lubricating layer; and a burnishing apparatus for burnishing the surface of the lubricating layer applied by the lubricant application apparatus with an abrasive, wherein the apparatus includes: a collection unit for collecting load amount data during the burnishing process; a storage unit for storing the collected load amount data; a calculation unit for performing calculations using the stored load amount data; and an alarm unit for alarming abnormalities in the film deposition apparatus or the lubricant application apparatus based on the calculation results from the calculation unit.

[0010] One aspect of the present invention is a method for producing a magnetic recording medium, comprising: a film formation step of forming at least a magnetic recording layer and a protective layer on a substrate in that order; a lubricant application step of applying a lubricant to the protective layer formed in the film formation step to form a lubricant layer; and a burnishing step of burning the surface of the lubricant layer applied in the lubricant application step with an abrasive, wherein the manufacturing conditions for the film formation step or the lubricant application step are set based on the load during the burnishing process.

[0011] One aspect of the present invention is a burnishing apparatus used in the production of magnetic recording media, which has an output unit that outputs data on the amount of load when burnishing a surface to be polished with an abrasive material to an external source. [Effects of the Invention]

[0012] According to one aspect of the present invention, it is possible to provide a magnetic recording medium production apparatus, a magnetic recording medium production method, and a burnishing apparatus that can detect the occurrence of defective products at an early stage or predict the occurrence of defective products during the production of magnetic recording media, thereby increasing the productivity of magnetic recording media. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows the configuration of a production apparatus for magnetic recording media according to one embodiment. [Figure 2]It is a cross-sectional view showing an example of a magnetic recording medium manufactured by a production apparatus for a magnetic recording medium according to an embodiment. [Figure 3] It is a diagram showing the relationship between the load amount during burnishing and the film thickness of the lubricating layer. [Figure 4] It is a diagram showing the relationship between the load amount during burnishing and the surface roughness of the workpiece. [Figure 5] It is a plan view of a film forming apparatus according to an embodiment. [Figure 6] It is a side view of a chamber of a film forming apparatus according to an embodiment. [Figure 7] It is a schematic configuration diagram of a lubricant coating apparatus by the dip method. [Figure 8] It is a schematic configuration diagram of a lubricant coating apparatus by the spin coating method. [Figure 9] It is a schematic configuration diagram of a lubricant coating apparatus by the vapor method. [Figure 10] It is a schematic configuration diagram of a burnishing apparatus according to an embodiment. [Figure 11] It is an enlarged cross-sectional view showing an example of a polishing tape used during burnishing. [Figure 12] It is a diagram for explaining the burnishing process.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For ease of understanding the description, the same reference numerals are given to the same components in each drawing, and duplicate descriptions are omitted as appropriate. Also, the scales of the members in the drawings may be different from the actual ones. In this specification, "~" indicating a numerical range means including the numerical values described before and after it as the lower limit value and the upper limit value, unless otherwise specified.

[0015] <Production Apparatus for Magnetic Recording Medium> FIG. 1 is a diagram showing the configuration of a production apparatus for a magnetic recording medium according to an embodiment. The production apparatus for the magnetic recording medium of this embodiment will be described with reference to FIG. 1. The production apparatus 60 for the magnetic recording medium of this embodiment includes a film forming apparatus 61, a lubricant coating apparatus 62, and a burnishing apparatus 63.

[0016] Further, the production apparatus 60 for the magnetic recording medium includes a collection unit 64 that collects data on the load amount during burnishing, a storage unit 65 that stores the collected load amount data, a calculation unit 66 that performs calculations using the stored load amount data, and a setting unit 67 that sets the manufacturing conditions of the film forming apparatus 61 or the lubricant coating apparatus 62 based on the calculation result by the calculation unit 66. In the example shown in FIG. 1, the production apparatus 60 for the magnetic recording medium further includes an alarm unit 68 that alarms an abnormality of the film forming apparatus 61 or the lubricant coating apparatus 62 based on the calculation result by the calculation unit 66.

[0017] The production apparatus 60 for the magnetic recording medium may not have the setting unit 67 and may include the film forming apparatus 61, the lubricant coating apparatus 62, the burnishing apparatus 63, the collection unit 64, the storage unit 65, the calculation unit 66, and the alarm unit 68.

[0018] The setting unit 67 may include a setting unit 67a that sets the manufacturing conditions of the film forming apparatus 61 and a setting unit 67b that sets the manufacturing conditions of the lubricant coating apparatus 62, or a single setting unit 67 may set the manufacturing conditions of the film forming apparatus 61 or the lubricant coating apparatus 62.

[0019] The alarm unit 68 may generate a sound, may turn on or flash a lamp, or may send an email to the person in charge. The alarm unit 68 may include an alarm unit 68a that alarms an abnormality of the film forming apparatus 61 and an alarm unit 68b that alarms an abnormality of the lubricant coating apparatus 62, or a single alarm unit 68a may alarm an abnormality of the film forming apparatus 61 or the lubricant coating apparatus 62.

[0020] In Figure 1, the collection unit 64 is located within the burnishing device 63. In this case, the burnishing device 63 has an output unit 69 that outputs data on the load amount during burnishing to the outside. The output unit 69 may output the data on the load amount during burnishing to the storage unit 65.

[0021] In an embodiment different from that shown in Figure 1, the collection unit 64 may be provided in another device outside the burnishing apparatus 63. The storage unit 65 and the calculation unit 66 may be provided inside the burnishing apparatus 63, the film deposition apparatus 61, or the lubricant application apparatus 62. Furthermore, an alarm unit 68a for warning of abnormalities in the film deposition apparatus 61 may be provided inside the film deposition apparatus 61, and an alarm unit 68b for warning of abnormalities in the lubricant application apparatus 62 may be provided inside the lubricant application apparatus 62.

[0022] In Figure 1, the setting unit 67a for setting the manufacturing conditions of the film deposition apparatus 61 is preferably performed automatically based on the calculation results of the calculation unit 66, but the manufacturing conditions of the film deposition apparatus 61 may also be set manually.

[0023] Furthermore, in Figure 1, the setting unit 67b for setting the manufacturing conditions of the lubricant application device 62 is preferably performed automatically based on the calculation results of the calculation unit 66, but the manufacturing conditions of the lubricant application device 62 may also be set manually.

[0024] Figure 2 is a cross-sectional view showing an example of a magnetic recording medium manufactured by a magnetic recording medium production apparatus according to one embodiment. As shown in Figure 2, the magnetic recording medium 1 manufactured by the magnetic recording medium production apparatus 60 has a lubricating layer 12 on both sides of a laminate (also referred to as a laminated body) 11.

[0025] The laminate 11 is provided with a magnetic recording layer 112 and a protective layer 113 laminated on both sides of the substrate 111 in that order, starting from the substrate 111 side.

[0026] The substrate 111 is made of a non-magnetic material. The substrate 111 may be a metal substrate made of a metallic material such as an aluminum alloy, or a non-metallic substrate made of a non-metallic material such as glass. Furthermore, an NiP alloy layer may be formed on the surface of these metal or non-metallic substrates using methods such as plating or sputtering.

[0027] The magnetic recording layer 112 is a layer provided for recording and reproducing information. For example, it is provided for storing data by reversing the direction of magnetization using magnetic energy supplied from the magnetic head of the HDD and maintaining that magnetization state.

[0028] The magnetic recording layer 112 uses FePt alloys having an L10 structure, CoPt alloys having an L10 structure, and CoCrPt alloys having an HCP (hexagonal close-packed) structure, among others.

[0029] For forming the magnetic recording layer 112, known methods such as sputtering and ion beam deposition can be used.

[0030] The protective layer 113 is provided to suppress corrosion of the magnetic recording layer 112, to prevent and protect the surface of the magnetic recording medium 1 from damage when the magnetic head comes into contact with the magnetic recording medium 1, and to improve the corrosion resistance of the magnetic recording medium 1.

[0031] The protective layer 113 can be formed from well-known materials, such as hard carbon films or diamond-like carbon (DLC).

[0032] For forming the protective layer 113, known methods such as sputtering and ion beam deposition can be used.

[0033] The protective layer 113 may have its surface hydrogenated or nitrogenated. By hydrogenating or nitrogenating its surface, the protective layer 113 can increase its bonding strength with the lubricating layer 12 formed on top of it. That is, since the first lubricant applied on the protective layer 113 has polarity, it forms a strong bond with the hydrogen and nitrogen atoms on the surface of the protective layer 113. In particular, it is preferable that the surface of the protective layer 113 be nitrogenized.

[0034] The lubricating layer 12 is provided to suppress wear on the surface of the magnetic head and the magnetic recording medium 1 when the magnetic head comes into contact with the magnetic recording medium 1, thereby improving the corrosion resistance of the magnetic recording medium 1.

[0035] The thickness of the lubricating layer 12 is preferably 5 Å to 10 Å. By setting the thickness of the lubricating layer 12 to 5 Å to 10 Å, wear on the surface of the magnetic recording medium 1 is suppressed, the corrosion resistance of the magnetic recording medium 1 is improved, and the distance between the magnetic head and the magnetic recording medium 1 in the HDD can be shortened to achieve high recording density.

[0036] The inventors of this application conducted a detailed analysis of the load during burnishing and found a correlation between the load during burnishing, the surface roughness of the workpiece, and the film thickness of the lubricating layer 12. By using this result to reset the manufacturing conditions of the film deposition apparatus 61 or the lubricant application apparatus 62 in the magnetic recording medium production apparatus 60, the occurrence of defective products in that apparatus can be prevented. In this specification, surface roughness refers to the arithmetic mean roughness (Ra), which can be measured, for example, in a 10 μm square area using an AFM (atomic force microscope).

[0037] Furthermore, if the magnetic recording medium production apparatus 60 cannot be addressed by resetting the manufacturing conditions, or if the conditions are not reset, it will issue an alarm, thereby stopping the film deposition apparatus 61 or the lubricant application apparatus 62, thereby preventing the occurrence of defective products in that apparatus.

[0038] Figure 3 shows the relationship between the load during burnishing and the film thickness of the lubricating layer. In Figure 3, the horizontal axis represents the peripheral speed (cm / sec) of the workpiece surface (surface of the lubricating layer 12) relative to the abrasive tape (tape containing abrasive) 40, which will be described later, and the pressure (gf / cm) applied by the abrasive tape 40 to the workpiece surface. 2 The values ​​shown are obtained by dividing by ). The vertical axis represents the tension (gf) applied to the polishing tape 40 during the burnishing process, and the relationship between the two was investigated by changing the film thickness of the lubricating layer 12 on the workpiece surface to 4.1 Å, 5.3 Å, and 8.0 Å.

[0039] As shown in Figure 3, changing the film thickness of the lubrication layer 12 changes the tension applied to the polishing tape 40, i.e., the load during the burning process. This change becomes more pronounced as the peripheral speed of the polishing tape 40 decreases or as the load increases.

[0040] Figure 4 shows the relationship between the load during burnishing and the surface roughness of the workpiece. Here, the workpiece is a laminate 11 with lubricating layers 12 formed on both sides. In Figure 4, the horizontal axis represents the peripheral speed (cm / sec) of the workpiece surface relative to the abrasive tape 40, and the pressure (gf / cm) applied by the abrasive tape 40 to the workpiece surface. 2 The values ​​shown are obtained by dividing by (). The vertical axis represents the tension (gf) applied to the abrasive tape 40 during processing, and the relationship between the two was investigated by changing the surface roughness of the workpiece to 2.14 nm and 1.55 nm.

[0041] As shown in Figure 4, changing the surface roughness of the workpiece changes the tension applied to the abrasive tape 40, i.e., the load during burnishing. This change becomes more pronounced as the peripheral speed of the abrasive tape 40 decreases or as the load increases.

[0042] From the above results, it can be seen that by collecting and storing the load during burnishing, and then using the stored information (load during burnishing, peripheral speed of the workpiece surface relative to the abrasive tape 40, pressure applied by the abrasive tape to the workpiece surface, tension applied to the abrasive tape 40 during burnishing, etc.) to perform calculations, it is possible to detect changes in the film thickness of the lubricating layer 12 on the workpiece surface and changes in the surface roughness of the workpiece. Therefore, by detecting changes in the film thickness of the lubricating layer 12 on the workpiece surface or changes in the surface roughness of the workpiece, it is possible to detect the occurrence of defective products early and to predict the occurrence of defective products. Furthermore, it becomes possible to reset (change) the manufacturing conditions of the film deposition apparatus 61 and the lubricant application apparatus 62 in accordance with changes in the film thickness of the lubricating layer 12 on the workpiece surface or changes in the surface roughness of the workpiece, and it becomes possible to detect abnormalities in the film deposition apparatus 61 and the lubricant application apparatus 62 and issue an alarm.

[0043] In other words, by using the magnetic recording medium production apparatus 60, it is possible to detect or predict the occurrence of defective products during the production of magnetic recording mediums at an early stage, thereby increasing the productivity of magnetic recording mediums.

[0044] Specifically, the calculation unit 66 can use the load data stored in the storage unit to calculate, for example, the change in the thickness of the lubricating layer 12 during the burning process in the burning apparatus 63, or the change in the surface roughness of the workpiece, based on the correlation shown in Figure 3 or Figure 4. In this case, the calculation result by the calculation unit 66 refers to the change in the thickness of the lubricating layer 12 or the change in the surface roughness of the workpiece.

[0045] [Film forming equipment] Figure 5 is a plan view of a film deposition apparatus according to one embodiment, and Figure 6 is a side view of the chamber of the film deposition apparatus according to one embodiment. In this embodiment, the case in which the film deposition apparatus 61 is an in-line film deposition apparatus will be described as an example. The film deposition apparatus 61 deposits at least a magnetic recording layer 112 and a protective layer 113 on the substrate 111 in this order.

[0046] Generally, methods such as sputtering, CVD, and PVD are used to deposit each layer of magnetic recording media. Often, the deposition process is carried out by first creating a vacuum inside the deposition apparatus and then introducing a processing gas. In such production methods, it is preferable to carry out the process continuously using as few deposition apparatuses as possible.

[0047] In-line film deposition equipment can improve the efficiency of the manufacturing process and the yield of products by continuously performing film deposition, thereby suppressing substrate contamination during handling or reducing handling steps, and increasing the productivity of magnetic recording media.

[0048] As shown in Figure 5, the film deposition apparatus 61 comprises a robot table 8, a substrate transfer robot 3 mounted on the robot table 8, a substrate attachment / detachment robot 2 adjacent to the robot table 8, and a plurality of corner chambers 4 for rotating the carrier 7. Furthermore, as shown in Figures 5 and 6, the film deposition apparatus 61 comprises a plurality of chambers 5 arranged between the corner chambers 4 for performing film deposition on the substrate 111, a plurality of carriers 7 that hold the substrate 111 and are sequentially transported through the plurality of corner chambers 4 and the plurality of chambers 5, and a processing mechanism 20 for processing both surfaces of the substrate 111. Note that in Figure 5, the processing mechanism 20 is provided in all of the chambers 5, but the notation of reference numeral 20 is partially omitted.

[0049] The film deposition apparatus 61 further includes a vacuum pump P for reducing the pressure inside multiple chambers 5 and a gate valve 6 for creating a sealed space inside each chamber 5. In Figure 5, vacuum pumps P are provided in all of the chambers 5, but the notation of the symbol P is partially omitted. In the example shown in Figure 5, gate valves 6 are provided at the connection points of each chamber 5, and when each gate valve 6 is closed, the inside of each chamber 5 becomes an independent sealed space. Each chamber 5 may also be connected to a vacuum pump P, and the operation of the vacuum pump P reduces the pressure inside each chamber 5. At least one of the multiple chambers 5 has a heating mechanism for the substrate 111 as a processing mechanism 20.

[0050] The film deposition apparatus 61 sequentially transports carriers 7 into each chamber 5 using a transport mechanism 13 (described later), and within each chamber 5, uses a processing mechanism 20 to sequentially deposit, for example, a soft magnetic layer, an intermediate layer, a magnetic recording layer 112, and a protective layer 113 onto both sides of the substrate 111 held by the carrier 7. After depositing the protective layer 113 onto the substrate 111, the substrate 111 is removed from the film deposition apparatus 61, and a lubricating layer 12 is deposited on both sides of the substrate 111 to finally obtain the magnetic recording medium 1 shown in Figure 2.

[0051] Each corner chamber 4 is a chamber that changes the direction of movement of the carrier 7, and a mechanism is provided inside each corner chamber 4 to rotate the carrier 7 and move it to the next chamber 5.

[0052] As shown in Figure 6, the film deposition apparatus 61 includes a transport mechanism 13 for transporting the carrier 7 into the gate valve 6 and the chamber 5. The transport mechanism 13 includes, for example, a linear motor drive mechanism that operates in a non-contact manner. The carrier 7 is provided with substrate holders 10 for holding the substrate 111 in a vertical position. Vertical positioning means that the main surface (front or back surface) of the substrate 111 is parallel to the vertical direction Z. In this embodiment, two substrate holders 10 are arranged on the carrier 7, but the number of substrate holders 10 provided on the carrier 7 is not limited.

[0053] The linear motor drive mechanism has multiple magnets arranged alternately with north and south poles at the bottom of the carrier 7, and below these magnets, separated by a partition, a rotating magnet with alternating north and south poles arranged in a spiral pattern is placed along the transport path. The linear motor drive mechanism transports the carrier 7 by rotating the rotating magnet around its axis while magnetically coupling the magnets on the carrier 7 side with the rotating magnet in a non-contact manner.

[0054] In the sputtering method, a target containing the material for forming the magnetic recording layer 112 can be used.

[0055] As a target containing the material for forming the magnetic recording layer 112, for example, an FePt-based alloy having an L10 structure, a CoPt-based alloy having an L10 structure, or a CoCrPt-based alloy having an HCP structure can be used.

[0056] Sputtering methods that can be used include DC sputtering, DC magnetron sputtering, and RF sputtering.

[0057] When forming the magnetic recording layer 112, RF (Radio Frequency) bias, DC bias, pulsed DC, and pulsed DC bias may be used as needed.

[0058] O2 gas, H2O gas, N2 gas, etc., may be used as the reactive gas.

[0059] The sputtering gas pressure is adjusted as needed to optimize the characteristics of each layer, but it is usually within the range of 0.1 Pa to 30 Pa.

[0060] The method for forming the protective layer 113 is not particularly limited, but general deposition methods such as RF-CVD (Radio Frequency-Chemical Vapor Deposition), which decomposes a hydrocarbon source gas with a high-frequency plasma to form a film; IBD (Ion Beam Deposition), which ionizes the source gas with electrons emitted from a filament to form a film; and FCVA (Filtered Cathodic Vacuum Arc), which uses a solid carbon target to form a film without using a source gas, can be used.

[0061] The film deposition process for each layer of the magnetic recording medium, particularly the deposition process for the protective layer 113, strongly affects the surface roughness of the magnetic recording medium. Therefore, if an abnormality is detected from the load during the varnishing process, the deposition conditions can be reset. If the issue cannot be resolved by resetting the deposition conditions, an alarm can be issued and the deposition equipment can be stopped to prevent the occurrence of defective products.

[0062] Specifically, the setting unit 67 may set the film deposition conditions of the film deposition apparatus 61, such as the film deposition time and film deposition speed, based on the calculation results from the calculation unit 66. This allows the setting unit 67 to readjust the manufacturing conditions of the film deposition apparatus 61 based on the calculation results from the calculation unit 66 to prevent the occurrence of defective products. As a result, the magnetic recording medium production apparatus 60 can suppress the occurrence of defective products at a stage before the burnishing process and increase the productivity of magnetic recording media.

[0063] The setting unit 67 may set the film deposition conditions of the film deposition apparatus 61, such as the film deposition time and film deposition speed, if it determines that the amount of change in the surface roughness of the workpiece, which is the result of calculation by the calculation unit 66, is greater than or equal to a predetermined threshold.

[0064] The alarm unit 68 may, based on the calculation results of the calculation unit 66, alarm the film deposition apparatus 61 if it determines that the change in the surface roughness of the workpiece is greater than or equal to a predetermined threshold. This allows the user to recognize the abnormality of the film deposition apparatus 61, thereby enabling the magnetic recording medium production apparatus 60 to suppress the occurrence of defective products at a stage before the burnishing process and increase the productivity of magnetic recording media. The alarm unit 68 may also alarm the film deposition apparatus 61 and stop the film deposition apparatus 61 if it determines, based on the calculation results of the calculation unit 66, that the change in the surface roughness of the workpiece is greater than or equal to a predetermined threshold.

[0065] [Lubricant application device] The lubricant application apparatus 62 applies lubricant onto the protective layer 113 formed by the film formation apparatus 61 to form a lubricating layer 12. Examples of the lubricant application apparatus 62 include lubricant application apparatuses using the dip method, spin coating method, vapor coating method, etc.

[0066] Figure 7 illustrates the operation of a lubricant application apparatus using the dip method. In Figure 7, the sequence of operations is shown in the order of (a) and (b). In the example shown in Figure 7, the lubricant application apparatus 30 includes a solution tank 330 containing a liquid 340 containing lubricant, an arm 310 that holds a substrate 111 (laminated body 11) formed by a film deposition apparatus 61, and a support column 320 that supports the arm 310 so that it can move vertically. That is, the arm 310 is mounted so that it can move vertically relative to the support column 320.

[0067] As shown in Figure 7(a), a liquid 340 containing a lubricant is placed in the solution tank 330, and the arm 310 to which the laminate 11 is fixed is lowered vertically at a constant speed into the liquid 340, immersing the laminate 11 in the liquid 340. Then, the arm 310 is raised vertically at a constant speed to the state shown in Figure 7(b), thereby forming a lubricating layer 12 on the surface of the laminate 11. Here, the laminate 11 is held by the arm 310 so that its inner circumference is caught in a V-shaped groove provided on the arm 310. The arm 310 is mounted so that it can move vertically relative to the support column 320.

[0068] The thickness of the lubrication layer 12 can be controlled by the lifting speed of the arm 310 or the lubricant concentration in the liquid 340. Therefore, if an abnormality in the thickness of the lubrication layer 12 is detected from the load during the burnishing process, the lifting speed of the arm 310 or the lubricant concentration in the liquid 340 can be readjusted. If the issue cannot be resolved by readjusting the lifting speed of the arm 310 or the lubricant concentration in the liquid 340, an alarm will be issued and the lubricant application device will be stopped to prevent the occurrence of defective products.

[0069] Specifically, the setting unit 67 may set the lifting speed of the arm 310 of the lubricant application device 30, or the concentration of the lubricant in the liquid 340, based on the calculation results from the calculation unit 66. This allows the setting unit 67 to readjust the manufacturing conditions of the lubricant application device 30 based on the calculation results from the calculation unit 66 to prevent the occurrence of defective products. As a result, the magnetic recording medium production apparatus 60 can suppress the occurrence of defective products at a stage before the burnishing process, thereby increasing the productivity of magnetic recording media.

[0070] If the setting unit 67 determines that the amount of change in the film thickness of the lubricating layer 12, which is the result of calculation by the calculation unit 66, is equal to or greater than a predetermined threshold, it may set one or more of the following: the setting of the lifting speed of the arm 310 of the lubricant application device 30, and the setting of the concentration of the lubricant in the liquid 340.

[0071] The alarm unit 68 may, based on the calculation results of the calculation unit 66, alarm the lubricant application device 62 if it determines that the change in the film thickness of the lubricant layer 12 is greater than or equal to a predetermined threshold. This allows the user to recognize the abnormality of the lubricant application device 62, thereby enabling the magnetic recording medium production device 60 to suppress the occurrence of defective products at a stage before the burnishing process and increase the productivity of the magnetic recording medium. The alarm unit 68 may also alarm the lubricant application device 62 and stop the lubricant application device 62 if it determines, based on the calculation results of the calculation unit 66, that the change in the film thickness of the lubricant layer 12 is greater than or equal to a predetermined threshold.

[0072] Figure 8 is a schematic diagram of a lubricant application apparatus using the spin coating method. As shown in Figure 8, the spin coating lubricant application apparatus 70 prepares a liquid 76 containing lubricant in a tank 71. After spraying this liquid 76 from nozzles 73 onto both surfaces of a laminate 11 chucked on a spindle 72, the laminate 11 is rotated at high speed for a certain period of time by a motor 74, forming a lubricating layer 12 on the laminate 11 by centrifugal force. Excess liquid 76 is discharged outside the apparatus from a drain port 75. The thickness of the lubricating layer 12 can be controlled by the rotation speed of the spindle 72 and the lubricant concentration in the liquid 76. Therefore, if an abnormality in the thickness of the lubricating layer 12 is detected from the load during burnishing, the rotation speed of the spindle 72 and the lubricant concentration in the liquid 76 are reset. If the problem cannot be resolved by resetting the rotation speed of the spindle 72 and the lubricant concentration in the liquid 76, an alarm is issued and the lubricating application apparatus 70 is stopped, preventing the occurrence of defective products.

[0073] Specifically, the setting unit 67 may set the rotation speed of the spindle 72 of the lubricant application device 70 or the concentration of the lubricant in the liquid 76 based on the calculation results from the calculation unit 66. This allows the setting unit 67 to readjust the manufacturing conditions of the lubricant application device 70 based on the calculation results from the calculation unit 66 to prevent the occurrence of defective products. As a result, the magnetic recording medium production device 60 can suppress the occurrence of defective products at a stage before the burnishing process and increase the productivity of magnetic recording media.

[0074] If the setting unit 67 determines that the amount of change in the film thickness of the lubricating layer 12, which is the result of calculation by the calculation unit 66, is equal to or greater than a predetermined threshold, it may set one or more of the following: the rotation speed of the spindle 72 of the lubricant application device 70, and the concentration of the lubricant in the liquid 76.

[0075] The alarm unit 68 may, based on the calculation results of the calculation unit 66, alarm the lubricant application device 70 if it determines that the change in the film thickness of the lubricant layer 12 is greater than or equal to a predetermined threshold. This allows the user to recognize the abnormality of the lubricant application device 70, thereby enabling the magnetic recording medium production device 60 to suppress the occurrence of defective products at a stage before the burnishing process and increase the productivity of the magnetic recording medium. The alarm unit 68 may also alarm the lubricant application device 70 and stop the device if it determines, based on the calculation results of the calculation unit 66, that the change in the film thickness of the lubricant layer 12 is greater than or equal to a predetermined threshold.

[0076] Figure 9 is a schematic diagram of a vapor-processing lubricant application apparatus. As shown in Figure 9, the vapor-processing lubricant application apparatus 80 places the laminate 11 on the mounting base 82 in the processing chamber 81, and then evacuates the processing chamber 81 with a vacuum pump 83. After this, a lubricant layer 12 is formed on the laminate 11 by introducing a lubricant 84 that has been gasified by heating into the processing chamber 81. After that, the processing chamber 81 is evacuated by vacuum, then the pressure inside the processing chamber 81 is returned to atmospheric pressure, and the processed substrate is removed from the processing chamber 81. The thickness of the lubricant layer 12 can be controlled by the amount of gasified lubricant introduced. Therefore, if an abnormality in the thickness of the lubricant layer 12 is detected from the load during burnishing, the amount of lubricant introduced is readjusted, and if the issue cannot be resolved by readjusting the amount of lubricant introduced, an alarm is issued and the lubricant application apparatus 80 is stopped, preventing the occurrence of defective products.

[0077] Specifically, the setting unit 67 may set the amount of lubricant introduced into the lubricant application device 80 based on the calculation results from the calculation unit 66. This allows the setting unit 67 to readjust the manufacturing conditions of the lubricant application device 80 based on the calculation results from the calculation unit 66 to prevent the generation of defective products. As a result, the magnetic recording medium production device 60 can suppress the generation of defective products at a stage before the burnishing process and increase the productivity of magnetic recording media.

[0078] The setting unit 67 may set the amount of lubricant introduced into the lubricant application device 80 to increase or decrease if it determines that the amount of change in the film thickness of the lubricant layer 12, which is the result of calculation by the calculation unit 66, is greater than or equal to a predetermined threshold.

[0079] The alarm unit 68 may, based on the calculation results of the calculation unit 66, alarm the lubricant application device 80 if it determines that the change in the film thickness of the lubricant layer 12 is greater than or equal to a predetermined threshold. This allows the user to recognize the abnormality of the lubricant application device 80, thereby enabling the magnetic recording medium production device 60 to suppress the occurrence of defective products at a stage before the burnishing process and increase the productivity of the magnetic recording medium. The alarm unit 68 may also alarm the lubricant application device 80 and stop it if it determines, based on the calculation results of the calculation unit 66, that the change in the film thickness of the lubricant layer 12 is greater than or equal to a predetermined threshold.

[0080] Organic compounds used as lubricants preferably contain functional groups such as hydroxyl groups, amino groups, amide groups, carbonyl groups, carboxyl groups, cyano groups, phenyl groups, and methyl groups, and among these, it is particularly preferable that they contain polar functional groups (polar groups) such as hydroxyl groups, amino groups, amide groups, carbonyl groups, carboxyl groups, and cyano groups.

[0081] The weight-average molecular weight (Mw) of the compounds constituting the lubricant is preferably 900 to 3000, and the structural formula of the lubricant preferably contains 4 to 8 of the aforementioned polar groups. In this specification, weight-average molecular weight refers to the value measured by gel permeation chromatography (GPC).

[0082] [Burning device] Figure 10 shows an example of a burnishing apparatus according to this embodiment. The burnishing apparatus 63 burns the surface of the lubricating layer 12 applied by the lubricant application apparatus 30 using an abrasive material. As shown in Figure 10, the burnishing apparatus 63 has a pair of abrasive tapes 40 arranged opposite each other so as to sandwich a laminate 11 on both sides, a rotation support means 51 (dashed line in the figure) that rotates the laminate 11 on both sides in the direction of arrow A, and a tape moving means 52 that moves the abrasive tape 40 in the direction of arrow B. The tape moving means 52 includes an abrasive tape supply reel 53, a number of guide rolls 523, and an abrasive tape winding reel 54.

[0083] Each set of abrasive tape 40 is supplied from the abrasive tape supply reel 53 in a roll-like state, and moves in the direction of arrow B while being guided by a number of guide rolls 523, and is then wound into a roll by the abrasive tape take-up reel 54 (some of the guide rolls, indicated by reference numeral 523, are omitted in the figure).

[0084] In the burnishing apparatus 63, polishing tapes 40 are positioned opposite each other so as to sandwich the laminate 11, which has lubricating layers 12 formed on both sides, allowing for efficient burnishing of both sides of the lubricating layer 12 simultaneously.

[0085] Figure 11 is an enlarged cross-sectional view showing an example of an abrasive tape 40 used during varnishing. As shown in Figure 11, the abrasive tape 40 polishes the lubricating layer 12 by sliding its polishing surface S against the surface of the lubricating layer 12.

[0086] The polishing tape 40 has an abrasive layer 42 on a support 41. The abrasive layer 42 has abrasive grains 421 and a binder 422 that binds the abrasive grains 421 together and also binds the abrasive grains 421 to the support 41, thereby fixing the abrasive grains 421 to the abrasive layer 42.

[0087] The material constituting the support 41 is not particularly limited, and various resins such as polyethylene terephthalate can be used.

[0088] Examples of abrasive particles 421 include particles containing chromium oxide, α-alumina, silicon carbide, nonmagnetic iron oxide, diamond, γ-alumina, α,γ-alumina, fused alumina, corundum, and artificial diamond. Two or more of these types may be appropriately combined to form the abrasive particles 421.

[0089] The binder 422 is not particularly limited, and for example, thermosetting resins, thermoplastic resins, photosensitive resins, etc., can be used. The resin used as the binder 422 may be used alone or in combination of two or more types.

[0090] Since the abrasive tape 40 is long, it is supplied in a rolled state, and in this state, it is set on the abrasive tape supply reel 53 of the burnishing device 63 for use.

[0091] The rotational support means 51 supports the central opening of the laminate 11, which has lubricating layers 12 formed on both sides, and rotates the laminate 11 in the circumferential direction (direction of arrow A). The direction of arrow A may be reversed.

[0092] The tape moving means 52 presses the abrasive tape 40 against both surfaces of the laminate 11, which has lubricating layers 12 formed on both sides, in the direction of arrow F, and moves the abrasive tape 40 relative to the laminate 11 in the radial direction as needed. The abrasive tape pressing means 521 is sometimes called a contact roll.

[0093] In the burnishing device 63, a tape tension sensor 55 and a tape tension controller 56 are provided in the abrasive tape travel system. The tape tension sensor 55 detects the tensile force (tape tension) applied to the abrasive tape and outputs it. The tape tension controller 56 eliminates the tensile force and deflection applied to the abrasive tape 40 when the abrasive tape pressing means 521 moves, and during burnishing, it keeps the tensile force applied to the abrasive tape 40 downstream from the abrasive tape pressing means 521 within a predetermined range. That is, when the abrasive tape pressing means 521 moves in the direction of arrow F, the abrasive tape 40 is pulled, and when it moves in the opposite direction of arrow F, the abrasive tape 40 deflects, but the tape tension controller 56 displaces in the direction of arrow C to eliminate this. In addition, during burnishing, the tape tension controller 56 applies a constant tension to the abrasive tape 40 downstream from the abrasive tape pressing means 521 to prevent the abrasive tape 40 from loosening.

[0094] In the burnishing device 63, the tensile force applied to the abrasive tape 40 can be controlled by the rotational force of the abrasive tape winding reel 54 and the abrasive tape supply reel 53. That is, by controlling the rotational force of the abrasive tape winding reel 54 and the abrasive tape supply reel 53 based on the tensile force of the abrasive tape 40 detected by the tape tension sensor 55, the tensile force applied to the abrasive tape 40 can be set to a predetermined value.

[0095] In the burnishing device 63, the tensile force applied to the abrasive tape 40 can be detected as a load in the direction of arrow D using the tape tension sensor 55. This can then be used as the load amount during the burnishing process. Specifically, the tensile force of the abrasive tape 40 is measured before the abrasive tape pressing means 521 presses the abrasive tape 40 against the lubrication layer 12 and the burnishing process is performed. Then, the tensile force of the abrasive tape 40 is measured during the burnishing process, and the load amount during the burnishing process can be calculated from the difference between the two.

[0096] Furthermore, the load during the burnishing process can also be calculated by considering the fluctuations in the load on the polishing tape pressing means 521 in the direction of arrow F, the fluctuations in the rotational force of the polishing tape winding reel 54, and the fluctuations in the rotational force of the polishing tape supply reel 53, both immediately before and during the burnishing process.

[0097] Specifically, the collection unit 64 collects data on the tensile force of the polishing tape 40 before pressing it against the lubricating layer 12 and performing burnishing, and the tensile force of the polishing tape 40 during burnishing, as load data. The output unit 69 outputs this data to the storage unit 65, and the storage unit 65 may store this data. The calculation unit 66 may then calculate the difference between the tensile force of the polishing tape 40 before pressing it against the lubricating layer 12 and performing burnishing, and the tensile force of the polishing tape 40 during burnishing. The calculation unit 66 may further use the result of this difference calculation to calculate the change in the film thickness of the lubricating layer 12 during burnishing in the burnishing apparatus 63, or the change in the surface roughness of the workpiece.

[0098] The collection unit 64 may collect data on load amounts, specifically the amount of load fluctuation in the direction of arrow F of the polishing tape pressing means 521, the amount of rotational force fluctuation of the polishing tape winding reel 54, or the amount of rotational force fluctuation of the polishing tape supply reel 53, immediately before and during the burnishing process. The output unit 69 may output this data to the storage unit 65, which may store this data. The calculation unit 66 may then use this data to calculate the change in the film thickness of the lubricating layer 12 or the change in the surface roughness of the workpiece during the burnishing process in the burnishing apparatus 63.

[0099] If the burnishing device 63 has an output unit 69 that outputs data on the amount of load when burnishing the surface to be polished with an abrasive, it becomes possible to detect the occurrence of defective products at an early stage during the production of magnetic recording media, and also to predict the occurrence of defective products.

[0100] <Production method for magnetic recording media> An example of a production method for a magnetic recording medium according to this embodiment will be described. The components used in each step are the same as those used in the magnetic recording medium production apparatus 60 described above, so their description will be omitted here. Also, the magnetic recording medium 1 manufactured by the production method for a magnetic recording medium according to this embodiment is the same as the magnetic recording medium 1 manufactured by the magnetic recording medium production apparatus 60 described above, so its description will be omitted here. The production method for a magnetic recording medium according to this embodiment includes a film formation step, a lubricant application step, and a varnish step.

[0101] [Film forming process] The production method for a magnetic recording medium includes a film deposition step of depositing at least a magnetic recording layer 112 and a protective layer 113 on a substrate 111 in that order. The film deposition step may be carried out using a film deposition apparatus 61.

[0102] [Lubricant application process] The production method for magnetic recording media includes a lubricant application step in which a lubricant is applied to a protective layer 113 formed by a film deposition step to form a lubricating layer 12.

[0103] Known methods such as the dipping method, spin coating method, and vapor coating method can be used to form the lubricating layer 12. The dipping method is a method in which the laminate 11 is immersed in a liquid containing dissolved lubricant, and then the laminate 11 is pulled up at a constant speed to form the lubricating layer 12 on the surface of the laminate 11. The spin coating method is a method in which the liquid containing dissolved lubricant is applied to the surface of the laminate 11, and then the laminate 11 is rotated at high speed for a certain period of time to form the lubricating layer 12 on the laminate 11. The vapor coating method is a method in which the laminate 11 is placed in a vacuum chamber, and a lubricant that has been gasified by heating is introduced into the vacuum chamber to form the lubricating layer 12 on the laminate 11. The lubricating application process may be carried out using a lubricating application device 30, a lubricating application device 70, or a lubricating application device 80.

[0104] [Burning process] The method for producing a magnetic recording medium includes a burning step in which the surface of the lubricant layer applied in the lubricant application step is burnished with an abrasive.

[0105] In the burning process, a method can be used in which an abrasive tape 40 is pressed against the surface of a laminate 11 on which a lubricating layer 12 is formed on both sides and rubbed. The burning method and burning apparatus will be described in detail with reference to the figures.

[0106] Figure 12 illustrates the burnishing process, where (a) is a partial cross-sectional view of the laminate 11 with the lubricating layer 12 formed on it before burnishing, and (b) is a diagram showing the state during burnishing. As shown in Figure 12(a), after applying lubricant to the laminate 11, a burnishing process is performed in which the surface of the laminate 11 with the lubricating layer 12 formed on both sides is burnished with polishing tape 40, as shown in Figure 12(b).

[0107] In the burning process, the laminate 11, on which lubricating layers 12 are formed on both sides, is rotated, and a tape containing abrasive material 21 is pressed against the surface of the lubricating layers 12 and rubbed. The rotation speed of the substrate in the burning process is, for example, within the range of 500 rpm to 3000 rpm. In Figure 12(b), the substrate is rotated clockwise, but it may also be rotated in the opposite direction. The burning process may be carried out using a burning apparatus 63.

[0108] The magnetic recording medium production method sets the manufacturing conditions for the film formation process or the lubricant application process based on the load during the burnishing process. The load during the burnishing process can be the same as that in the magnetic recording medium production apparatus 60 described above. As a result, the magnetic recording medium production method makes it possible to detect the occurrence of defective products at an early stage and to predict the occurrence of defective products during the production of magnetic recording media.

[0109] The magnetic recording medium production method detects abnormalities in the film formation process or lubricant application process based on the load during the burnishing process. The load during the burnishing process can be the same as that in the magnetic recording medium production apparatus 60 described above. As a result, the magnetic recording medium production method makes it possible to detect the occurrence of defective products at an early stage and to predict the occurrence of defective products during the production of magnetic recording media.

[0110] As described above, embodiments have been explained, but these embodiments are presented as examples only, and the present invention is not limited by these embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, and modifications are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0111] 1 Magnetic recording medium 11 Laminate 111 circuit board 112 Magnetic recording layer 113 Protective layer 2. Circuit board mounting / removal robot 3. Circuit board transfer robot 4 Corner Room 5 Chambers 6 Gate valve 7 Carriers 8 Robot stand 10. PCB holder 11 Laminated body (laminated body) 12 Lubricating layer 13. Conveying mechanism 20 Processing mechanism 30. Lubricant application device using the dip method 40 Abrasive Tapes 41 Support 42 Abrasive layer 51 Rotating support means 52 Tape transport means 53. Polishing tape supply reel 54. Abrasive tape winding reel 60 Production equipment for magnetic recording media 61 Film deposition equipment 62 Lubricant application device 63 Burnishing device 64 Collection Department 65 Storage Unit 66 Arithmetic section 67 Settings Section 68 Alarm section 69 Output section 70 Lubricant application apparatus using spin coating method 71 tanks 72 spindles 73 nozzles 74 Motor 80. Lubricant application apparatus using the vapor method 81 Processing Room 82 Installation stand 83 Vacuum pump 84 Lubricant 310 Arm 320 Post 330 Solution tank 340 liquid 421 abrasive grains 422 Binder 521 Abrasive tape pressing means (contact roll) 523 Guide Roll S polished surface P Vacuum pump Z vertical direction

Claims

1. A film deposition apparatus for depositing at least a magnetic recording layer and a protective layer on a substrate in this order, A lubricant application apparatus that applies a lubricant onto the protective layer formed by the aforementioned film-forming apparatus to form a lubricating layer, A production apparatus for magnetic recording media, comprising a burnishing apparatus for burning the surface of the lubricating layer applied by the lubricant application apparatus with an abrasive, A data collection unit for collecting data on the load during the burnishing process, A storage unit for storing the collected load data, A calculation unit that performs calculations using the stored load data, A magnetic recording medium production apparatus having a setting unit that sets the manufacturing conditions of the film-forming apparatus or the lubricant coating apparatus based on the calculation results of the calculation unit.

2. The production apparatus for a magnetic recording medium according to claim 1, wherein the calculation unit uses the stored load amount data to calculate the amount of change in the film thickness of the lubricating layer during the burnishing process, or the amount of change in the surface roughness of the workpiece during the burnishing process.

3. The lubricant application apparatus comprises a solution tank containing a liquid containing the lubricant, an arm for holding a substrate that has been film-formed by the film-forming apparatus, and a support column that supports the arm so that it can move vertically. The magnetic recording medium production apparatus according to claim 1 or 2, wherein the setting unit sets the lifting speed of the arm of the lubricant application apparatus or the concentration of the lubricant in the liquid based on the calculation result of the calculation unit.

4. A film deposition apparatus for depositing at least a magnetic recording layer and a protective layer on a substrate in this order, A lubricant application apparatus that applies a lubricant onto the protective layer formed by the aforementioned film-forming apparatus to form a lubricating layer, A production apparatus for magnetic recording media, comprising a burnishing apparatus for burnishing the surface of the lubricating layer applied by the lubricant application apparatus with an abrasive, A data collection unit for collecting data on the load during the burnishing process, A storage unit for storing the collected load data, A calculation unit that performs calculations using the stored load data, A magnetic recording medium production apparatus having an alarm unit that alerts for an abnormality in the film-forming apparatus or the lubricant coating apparatus based on the calculation results of the calculation unit.

5. The production apparatus for a magnetic recording medium according to claim 4, wherein the calculation unit uses the stored load amount data to calculate the amount of change in the thickness of the lubricating layer during the burnishing process, or the amount of change in the surface roughness of the workpiece during the burnishing process.

6. The production apparatus for magnetic recording media, according to claim 5, which, based on the calculation results of the calculation unit, determines that the amount of change in the film thickness of the lubricant layer is greater than or equal to a predetermined threshold, and then alerts the lubricant coating apparatus to an abnormality.

7. A film deposition step in which at least a magnetic recording layer and a protective layer are deposited on a substrate in this order, A lubricant application step involves applying a lubricant onto the protective layer formed by the aforementioned film formation step to form a lubricating layer, A method for producing a magnetic recording medium, comprising a burning step of burning the surface of the lubricant layer applied by the lubricant application step with an abrasive, A method for producing a magnetic recording medium, wherein the manufacturing conditions for the film formation process or the lubricant application process are set based on the load during the burnishing process.

8. A film deposition step in which at least a magnetic recording layer and a protective layer are deposited on a substrate in this order, A lubricant application step involves applying a lubricant onto the protective layer formed by the aforementioned film formation step to form a lubricating layer, A method for producing a magnetic recording medium, comprising a burning step of burning the surface of the lubricant layer applied by the lubricant application step with an abrasive, A method for producing a magnetic recording medium, which detects an abnormality in the film formation process or the lubricant application process based on the load during the burnishing process.

9. A burnishing apparatus for the production of magnetic recording media, comprising an output unit that outputs data on the amount of load when burnishing a surface to be polished with an abrasive material.

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