JP2011227966A - Method of manufacturing magnetic recording medium and method of controlling orientation of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress remaining of wrong information on a magnetic recording medium after magnetic transfer.SOLUTION: After the magnetic recording medium 1 having a vertical recording layer 150 formed on each side of a substrate is applied with an AC magnetic field first to demagnetize the vertical recording layers 150, a DC magnetic field is applied in one direction to put the magnetism of the vertical recording layer 150 orderly in the one direction. Then a master information recording body which has unevenness formed in conformity with a servo pattern is brought into contact with the magnetic recording medium 1 whose vertical recording layers 150 have their magnetism put orderly in the one direction, and a DC magnetic field is applied in the opposite direction from the one direction to locally invert the direction of the magnetism of the vertical recording layers 150, thereby forming the servo pattern comprising an array in the direction of the magnetism on the magnetic recording medium 1.

Description

  The present invention relates to a method for manufacturing a magnetic recording medium and a method for controlling the orientation of a magnetic recording medium.

In a magnetic recording apparatus typified by a hard disk drive or the like, data is written to and read from a rotating magnetic recording medium using a magnetic head.
In this type of magnetic recording apparatus, the magnetic head is positioned in order to move the magnetic head to a target position on the magnetic recording medium and to write and read data at that position. For this reason, positioning data that is read by the magnetic head and used for positioning the magnetic head is recorded on the magnetic recording medium in advance.

  As a prior art described in the publication, it has been proposed to record positioning data and the like on a magnetic recording medium by a so-called magnetic transfer system. In the magnetic transfer method, first, a direct current magnetic field is applied to the magnetic transfer medium to perform initial magnetization that aligns the magnetization direction of the magnetic layer of the magnetic transfer medium in one direction, and then magnetic transfer of the pattern to the magnetic recording medium is performed. I do. In magnetic transfer, a magnetic recording medium is superimposed on a pattern forming body on which a pattern corresponding to data to be recorded is formed, and the initial magnetization is reversed with the pattern forming body and the magnetic medium interposed therebetween. By applying a DC magnetic field, the pattern is magnetically transferred to the magnetic recording medium (see Patent Document 1).

JP 2009-295250 A

  By the way, when the initial magnetization on the magnetic recording medium is insufficient, in addition to the data to be recorded magnetically transferred from the pattern forming body on the magnetic recording medium after magnetic transfer, there is data that should not be recorded. It will exist. When a magnetic recording apparatus is configured using such a magnetic recording medium, the magnetic head may become inaccurate as the magnetic head reads data that should not be recorded. there were.

  An object of the present invention is to suppress erroneous information from remaining on a magnetic recording medium after magnetic transfer.

  The method of manufacturing a magnetic recording medium according to the present invention includes a step of applying an alternating magnetic field to a magnetic recording medium having a magnetic layer laminated on a substrate, and a direct-current magnetic field in a first direction to the magnetic recording medium to which the alternating magnetic field is applied. In a state where the pattern forming body in which the pattern is formed is brought into contact with the magnetic recording medium to which the direct current magnetic field in the first direction is applied, the direct current in the second direction opposite to the first direction is applied. Applying a magnetic field.

In such a manufacturing method, in the step of applying an alternating magnetic field, an alternating magnetic field is applied in a non-contact manner to the magnetic recording medium, and in a step of applying a direct current magnetic field in the first direction, the magnetic recording medium is brought into non-contact. A DC magnetic field can be applied.
The magnetic layer is formed by recording information by a perpendicular magnetic recording method. In the step of applying an alternating magnetic field, the alternating magnetic field is applied in a direction perpendicular to the surface of the magnetic layer, and the first direction In the step of applying a direct current magnetic field, a direct current magnetic field in a first direction is applied in a direction perpendicular to the surface of the magnetic layer, and in a step of applying a direct current magnetic field in the second direction, the surface perpendicular to the surface of the magnetic layer is applied. A direct-current magnetic field having a second direction can be applied in the direction.

  The method for producing a magnetic recording medium of the present invention includes a step of demagnetizing a magnetic layer in a magnetic recording medium having a magnetic layer laminated on a substrate, and a direction of magnetization of the magnetic layer in the magnetic recording medium having the magnetic layer demagnetized. And a step of locally orienting the direction of magnetization of the magnetic layer in the magnetic recording medium in which the magnetic layer is oriented in one direction opposite to the one direction.

  In such a manufacturing method, the magnetic layer is formed by recording information by a perpendicular magnetic recording method. In the step of orienting the magnetization direction of the magnetic layer in one direction, one direction is set to the surface of the magnetic layer. It can be characterized by a vertical direction.

  Furthermore, the method for controlling the orientation of a magnetic recording medium according to the present invention includes a step of demagnetizing a magnetic layer in a magnetic recording medium having a magnetic layer laminated on a substrate, and a magnetization of the magnetic layer in the magnetic recording medium demagnetized. And orienting the direction in one direction.

  According to the present invention, it is possible to suppress erroneous information from remaining on a magnetic recording medium after magnetic transfer.

It is the figure which showed an example of the structure of the magnetic recording / reproducing apparatus provided with the magnetic recording medium with which this Embodiment is applied. It is a figure which shows an example of the cross-sectional structure of a magnetic recording medium. It is a top view of a magnetic recording medium. 3 is a flowchart showing an example of a method for manufacturing a magnetic recording medium in the present embodiment. It is a figure which shows an example of a structure of the initial stage magnetization apparatus used at an initial stage magnetization process. It is a flowchart which shows an example of the initial stage magnetization process which an initial stage magnetization apparatus performs. It is the figure which showed typically the state of the perpendicular recording layer of the magnetic recording medium in each process of an initial stage magnetization process. It is sectional drawing which shows an example of a structure of the magnetic transfer apparatus used at a magnetic transfer process. It is a perspective view which shows the outline of a structure of a magnetic transfer apparatus. It is a figure which shows an example of a structure of the master information recording body used with a magnetic transfer apparatus. It is the figure which showed typically the state of the perpendicular recording layer of the magnetic recording medium before and after passage of the 1st magnet and the 2nd magnet.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing an example of the configuration of a magnetic recording / reproducing apparatus including a magnetic recording medium 1 to which the present embodiment is applied.
This magnetic recording / reproducing apparatus includes a magnetic recording medium 1 that magnetically records data, a rotation drive unit 2 that rotationally drives the magnetic recording medium 1, and data that is written to the magnetic recording medium 1 and recorded on the magnetic recording medium 1. A magnetic head 3 for reading data, a carriage 4 on which the magnetic head 3 is mounted, a head drive unit 5 for moving the magnetic head 3 relative to the magnetic recording medium 1 via the carriage 4, and information input from the outside And a signal processing unit 6 that outputs a recording signal obtained by processing the above to the magnetic head 3 and outputs information obtained by processing the reproduction signal from the magnetic head 3 to the outside.
Here, in the present embodiment, the magnetic recording medium 1 has a disk shape, and recording layers for recording data are formed on both sides thereof as will be described later. In the example shown in FIG. 1, a plurality (three in this case) of magnetic recording media 1 are attached to one magnetic recording / reproducing apparatus.

FIG. 2 is a diagram showing an example of a cross-sectional configuration of the magnetic recording medium 1 shown in FIG. In addition, although there are an in-plane recording method and a perpendicular recording method as a data recording method for the magnetic recording medium 1, in this embodiment, the magnetic recording medium 1 used in the perpendicular recording method will be described.
The magnetic recording medium 1 is formed on a substrate 100, an adhesion layer 110 formed on the substrate 100, a soft magnetic underlayer 120 formed on the adhesion layer 110, and a soft magnetic underlayer 120. The orientation control layer 130, the nonmagnetic underlayer 140 formed on the orientation control layer 130, the perpendicular recording layer 150 formed on the nonmagnetic underlayer 140, and the perpendicular recording layer 150 are formed. The protective layer 160 and the lubricating layer 170 formed on the protective layer 160 are provided. In this embodiment, the adhesion layer 110, the soft magnetic underlayer 120, the orientation control layer 130, the nonmagnetic underlayer 140, the perpendicular recording layer 150, the protective layer 160, and the lubricating layer 170 are formed on both surfaces of the substrate 100, respectively. Is to be formed. In the following description, a laminate substrate in which the adhesive layer 110 to the protective layer 160 are laminated on both surfaces of the substrate 100 as necessary, in other words, a laminate substrate other than the lubrication layer 170 is formed. Sometimes referred to as 180.

  In this embodiment, a non-magnetic material is used as the substrate 100, and a metal substrate made of a metal material such as aluminum or an aluminum alloy may be used. For example, glass, ceramic, silicon, silicon carbide, carbon, etc. You may use the nonmetallic board | substrate which consists of these nonmetallic materials. In addition, it is also possible to use a substrate in which a NiP layer or a NiP alloy layer is formed on the surface of the metal substrate or nonmetal substrate by using, for example, a plating method or a sputtering method.

  Among these, as a glass substrate, normal glass, crystallized glass, etc. can be used, for example, General-purpose soda-lime glass, aluminosilicate glass, etc. can be used as normal glass, for example. In addition, as the crystallized glass, for example, lithium-based crystallized glass can be used. As the ceramic substrate, for example, a general-purpose aluminum oxide, a sintered body mainly composed of aluminum nitride, silicon nitride, or the like, or a fiber reinforced material thereof can be used.

  Further, as described later, when the substrate 100 is in contact with the soft magnetic underlayer 120 containing Co or Fe as a main component, corrosion can proceed due to surface adsorption gas, influence of moisture, diffusion of substrate components, and the like. There is sex. For this reason, it is preferable to provide the adhesion layer 110 between the substrate 100 and the soft magnetic underlayer 120. In addition, as a material of the adhesion layer 110, for example, Cr, Cr alloy, Ti, Ti alloy, or the like can be appropriately selected. The thickness of the adhesion layer 110 is preferably 2 nm (20 mm) or more.

The soft magnetic underlayer 120 is provided in order to reduce noise during recording and reproduction when the perpendicular recording method is employed.
In the present embodiment, the soft magnetic underlayer 120 includes a first soft magnetic layer 121 formed on the adhesion layer 110, a spacer layer 122 formed on the first soft magnetic layer 121, and a spacer layer 122. And a second soft magnetic layer 123 formed thereon. That is, the soft magnetic underlayer 120 has a configuration in which the spacer layer 122 is sandwiched between the first soft magnetic layer 121 and the second soft magnetic layer 123.
Of these, the first soft magnetic layer 121 and the second soft magnetic layer 123 are preferably made of a material containing Fe: Co in the range of 40:60 to 70:30 (atomic ratio). In order to enhance the corrosion resistance, it is preferable to contain any one selected from the group consisting of Ta, Nb, Zr, and Cr in the range of 1 atomic% to 8 atomic%.
As the spacer layer 122, Ru, Re, Cu, or the like can be used. Among these, it is particularly preferable to use Ru.

The orientation control layer 130 is provided in order to refine the crystal grains of the perpendicular recording layer 150 laminated thereon via the nonmagnetic underlayer 140 to improve the recording / reproducing characteristics.
The material constituting the orientation control layer 130 is not particularly limited, but a material having an hcp structure, an fcc structure, or an amorphous structure is preferable. In particular, a Ru-based alloy, a Ni-based alloy, a Co-based alloy, a Pt-based alloy, and a Cu-based alloy are preferable, and those obtained by multilayering these alloys may be used. For example, it is preferable to adopt a multilayer structure of Ni-based alloy and Ru-based alloy, a multilayer structure of Co-based alloy and Ru-based alloy, or a multilayer structure of Pt-based alloy and Ru-based alloy from the substrate 100 side.

The nonmagnetic underlayer 140 is provided in order to suppress disorder of crystal growth in the initial layered portion of the perpendicular recording layer 150 stacked thereon, and to suppress generation of noise during recording and reproduction. However, the nonmagnetic underlayer 140 is not necessarily provided.
In the present embodiment, the nonmagnetic underlayer 140 is preferably made of a material containing an oxide in addition to a metal containing Co as a main component. The Cr content in the nonmagnetic underlayer 140 is preferably 25 atomic% to 50 atomic%. As the oxide in the nonmagnetic underlayer 140, for example, an oxide such as Cr, Si, Ta, Al, Ti, Mg, and Co is preferably used, and among them, TiO ₂ , Cr ₂ O ₃ , SiO _{2 and the} like are particularly preferable. Can be suitably used. The content of the oxide in the nonmagnetic underlayer 140 is 3 mol% or more and 18 mol% or less with respect to the total mol of the magnetic particles, for example, an alloy such as Co, Cr, and Pt calculated as one compound. It is preferable.

  In the present embodiment, the perpendicular recording layer 150 includes a first magnetic layer 151 formed on the nonmagnetic underlayer 140, a first nonmagnetic layer 152 formed on the first magnetic layer 151, and a first A second magnetic layer 153 formed on the nonmagnetic layer 152, a second nonmagnetic layer 154 formed on the second magnetic layer 153, and a third formed on the second nonmagnetic layer 154 And a magnetic layer 155. That is, in the perpendicular recording layer 150, the first nonmagnetic layer 152 is sandwiched between the first magnetic layer 151 and the second magnetic layer 153, and the second nonmagnetic layer 154 is formed between the second magnetic layer 153 and the third magnetic layer 155. It has a sandwiched configuration.

Among these, the first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155 as examples of the magnetic layer are magnetized in the thickness direction of the perpendicular recording layer 150 by the magnetic energy supplied from the magnetic head 3. It is provided for storing data by reversing the direction and maintaining the state.
The first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155 include magnetic particles made of a metal containing Co as a main component and a nonmagnetic oxide, and the magnetic particles are surrounded by an oxide. Those having a mold structure are preferably used.

Here, as the oxide constituting the first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155, for example, an oxide such as Cr, Si, Ta, Al, Ti, Mg, Co is used. preferable. Among _{them, TiO 2, Cr 2 O 3} , SiO ₂ or the like can be suitably used. Further, the first magnetic layer 151 which is the lowest layer in the perpendicular recording layer 150 preferably contains a composite oxide composed of two or more kinds of oxides. Among these, Cr ₂ O ₃ —SiO ₂ , Cr ₂ O ₃ —TiO ₂ , Cr ₂ O ₃ —SiO ₂ —TiO _{2 and the} like can be preferably used.

In addition, as a material suitable for the magnetic particles constituting the first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155, for example, 90 (Co14Cr18Pt) -10 (SiO ₂ ) {Cr content 14 atomic% , Pt content of 18 atomic%, the molar concentration calculated as a single compound of magnetic particles composed of the remaining Co is 90 mol%, the oxide composition composed of SiO ₂ is 10 mol%}, 92 (Co 10 Cr 16 Pt) -8 (SiO ₂ ), other _{94 (Co8Cr14Pt4Nb) -6 (Cr 2} O 3), (CoCrPt) - (Ta 2 O 5), (CoCrPt) - (Cr 2 O 3) - (TiO 2), (CoCrPt) - (Cr 2 O _{3) - (SiO 2),} (CoCrPt) - (Cr 2 O 3) - (SiO 2) - (TiO 2), (CoCrPtMo) - (Ti _{), (CoCrPtW) - (TiO} 2), (CoCrPtB) - (Al 2 O 3), (CoCrPtTaNd) - (MgO), (CoCrPtBCu) - (Y 2 O 3), (CoCrPtRu) - (SiO 2) , etc. Can be mentioned.

Further, the first nonmagnetic layer 152 and the second nonmagnetic layer 154 facilitate the magnetization reversal of the first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155 constituting the perpendicular recording layer 150. It is provided to reduce noise by reducing dispersion of magnetization reversal in the entire magnetic particles.
In the present embodiment, it is preferable that the first nonmagnetic layer 152 and the second nonmagnetic layer 154 include, for example, Ru and Co.

  In this example, the magnetic layers constituting the perpendicular recording layer 150 are three layers (the first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155). However, the present invention is not limited to this. It is also possible to have a configuration including more than one magnetic layer. In this example, the nonmagnetic layer (the first nonmagnetic layer 152 and the first magnetic layer 152) is interposed between the magnetic layers (the first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155) constituting the perpendicular recording layer 150. However, the present invention is not limited to this. For example, two magnetic layers having different compositions may be arranged in an overlapping manner.

The protective layer 160 is provided to suppress corrosion of the perpendicular recording layer 150 and to prevent and protect the surface of the magnetic recording medium 1 from being damaged when the magnetic head 3 comes into contact with the magnetic recording medium 1.
As the protective layer 160, a conventionally known material can be used. For example, a material containing C, SiO ₂ , or ZrO ₂ can be used. The thickness of the protective layer 160 is preferably 1 to 10 nm because the distance between the magnetic head 3 and the magnetic recording medium 1 can be reduced in the magnetic recording / reproducing apparatus shown in FIG.

The lubricating layer 170 is provided to suppress wear of the surfaces of the magnetic head 3 and the magnetic recording medium 1 when the magnetic head 3 comes into contact with the magnetic recording medium 1.
As the lubricating layer 170, a conventionally known material can be used. For example, it is preferable to use a lubricant such as perfluoropolyether, fluorinated alcohol, or fluorinated carboxylic acid. The thickness of the lubrication layer 170 is preferably 1 to 2 nm because the distance between the magnetic head 3 and the magnetic recording medium 1 can be reduced in the magnetic recording / reproducing apparatus shown in FIG.

FIG. 3 is a top view of the magnetic recording medium 1 shown in FIG. FIG. 3 schematically shows a plurality of data areas provided on the surface of the magnetic recording medium 1.
The magnetic recording medium 1 in the present embodiment has a disk shape as described above, and a circular hole penetrating the front and back of the magnetic recording medium 1 is formed at the center thereof. In the following description, the edge of the circular hole in the magnetic recording medium 1 is referred to as an inner end 1a, and the outer peripheral edge in the magnetic recording medium 1 is referred to as an outer end 1b.

  On the surface of the magnetic recording medium 1 shown in FIG. 3, a read / write data storage area A1 for reading and writing data using the magnetic head 3 (see FIG. 1), and a magnetic head for reading and writing data using the magnetic head 3 And a positioning data storage area A2 for storing data used for positioning (referred to as positioning data). In this example, a plurality of positioning data storage areas A <b> 2 are provided radially on the surface of the magnetic recording medium 1. A plurality of tracks T are provided concentrically on the surface of the magnetic recording medium 1. Although not shown, a read / write data storage area A1 and a positioning data storage area A2 are similarly provided on the back surface of the magnetic recording medium 1 shown in FIG. However, the positioning data storage areas A2 provided on the front and back surfaces of the magnetic recording medium 1 may not be aligned on the front and back surfaces.

  In the positioning data storage area A2 of the magnetic recording medium 1, as positioning data, for example, an AGC (Auto Gain Control) pattern used for gain adjustment of a detection signal at the time of reading by the magnetic head 3, a detection used for detection of a servo signal Pattern, address pattern used for detecting cylinder information or sector information of servo track, and moving the magnetic head 3 to the target track T and then making the magnetic head 3 follow the track T Servo patterns including burst patterns (none of which are shown) are stored. The servo pattern is configured by appropriately reversing the magnetization direction in the thickness direction of the perpendicular recording layer 150 provided on the magnetic recording medium 1 in accordance with the positioning data.

  FIG. 4 is a flowchart showing an example of a method for manufacturing the magnetic recording medium 1 in the present embodiment. In the present embodiment, in the manufacturing process of the magnetic recording medium 1, the servo pattern is written in the positioning data storage area A2, and more specifically, a master information recording body 200 (FIG. 8) described later. The servo pattern is magnetically transferred to the magnetic recording medium 1 using the reference

  Prior to the manufacture of the magnetic recording medium 1, a substrate 100 is prepared which is previously formed in a disc shape and has a circular hole penetrating the front and back at the center, and after pre-cleaning, the substrate 100 is polished. (Step 101). The polishing of the substrate 100 in step 101 is desirably performed by, for example, mechanical polishing using diamond slurry.

  The polished substrate 100 has an average surface roughness (Ra) of 1 nm (10 cm) or less, preferably 0.5 nm or less, which is a high flying height of the magnetic head 3 (see FIG. 1). This is preferable because it is suitable for recording density recording. Further, the fine waviness (Wa) on the surface of the substrate 100 after polishing is 0.3 nm or less (more preferably 0.25 nm or less), which is suitable for high recording density recording with the magnetic head 3 flying low. This is preferable. In addition, a surface average roughness (Ra) of at least one of the chamfered portion of the chamfer portion on the end surface of the substrate 100 after polishing and the side surface portion should be 10 nm or less (more preferably 9.5 nm or less). Is preferable for the flight stability of the magnetic head 3. In addition, microwaviness (Wa) can be measured as surface average roughness in a measuring range of 80 μm, for example, using a surface roughness measuring device P-12 (manufactured by KLM-Tencor).

  Next, pre-cleaning is performed on the polished substrate 100 (step 102). It is preferable to perform the pre-cleaning of the substrate 100 in step 102 while immersing the polished substrate 100 in pure water or ultrapure water and applying ultrasonic vibration. The substrate 100 that has been pre-cleaned is preferably quickly dried by a spin method or the like.

  Subsequently, a film forming process in which the adhesion layer 110, the soft magnetic underlayer 120, the orientation control layer 130, the nonmagnetic underlayer 140, the perpendicular recording layer 150, and the protective layer 160 are sequentially stacked on the substrate 100 that has been pre-cleaned. (Step 103). Here, from the viewpoint of improving productivity, the formation of each layer in step 103 is preferably performed, for example, with an in-line film forming apparatus in which a plurality of chambers each having a film forming function are connected in series. Also, from the viewpoint of improving productivity, it is desirable to form each layer formed in the film formation step by a sputtering method. However, from the viewpoint of reducing the thickness of the protective layer 160 while ensuring the strength, it is preferable that the adhesive layer 110 to the perpendicular recording layer 150 are formed by sputtering, while the protective layer 160 is formed by CVD. . In this manner, by performing the film forming process on the substrate 100 that has been subjected to the pre-cleaning, the laminated substrate 180 (see FIG. 2) is obtained.

  Then, post-cleaning is performed on the laminated substrate 180 obtained by the film forming process (step 104). Hydrogen water can be used for the post-cleaning of the laminated substrate 180 in step 104. Here, the hydrogen water is water in which high-purity hydrogen gas is dissolved in pure water or ultrapure water, and the water capacity is reduced to increase the cleaning ability.

  The post-cleaning process of the present embodiment is performed for the purpose of removing contaminants on the surface of the laminated substrate 180 that cannot be removed by the wiping process (step 107) and the burnishing process (step 108) described later. These contaminants may be difficult to wash and remove with hydrogen water after the lubricant application step (step 105) described later, the wiping step, and the burnishing step. The reason for this is speculated that if the contaminants are covered with the lubricating layer 170, the water repellency makes it difficult to remove the contaminants, and the contaminants are applied to the surface of the laminated substrate 180 after the wiping process and the burnishing process. It may be difficult to remove. Note that although it is possible to remove powdery substances such as sputter dust to some extent also by a post-cleaning process using hydrogen water, the surface of the multilayer substrate 180 is scrubbed as in the wiping process and the burnishing process, Since the effect of wiping or shaving is low, it is difficult to remove the powdery substance that is firmly attached to the surface of the multilayer substrate 180. Therefore, the post-cleaning step using hydrogen water is preferably used in combination with the wiping step or the burnishing step.

  In the post-cleaning step, it is preferable that the laminated substrate 180 on which the protective layer 160 is formed is immersed in a cleaning tank containing hydrogen water. In particular, in the production of the magnetic recording medium 1, by providing a post-cleaning process, it cannot be removed in the wiping process or the burnishing process, and is transferred and accumulated in the master information recording body 200 in the magnetic transfer process (step 111) described later. This has the effect of effectively removing contaminants and making the laminated substrate 180 less likely to corrode during the post-cleaning step.

Here, the post-cleaning step in the present embodiment will be described with a specific example. Depending on the number of laminated substrates 180 to be introduced, for example, when processing 100 laminated substrates 180 having an outer diameter of 2.5 inches in a batch system, a resin or stainless alloy immersion layer having a volume of about 30 liters is used. Hydrogen water having a dissolved hydrogen concentration in pure water in the range of 0.1 ppm to 5 ppm is put in, the oxidation-reduction potential of this hydrogen water is in the range of -200 mV to -800 mV, and the amount of KOH or NH ₄ OH In the range of 0.05 ppm to 5 ppm, if necessary, a slight amount of weakly alkaline surfactant is added, an ultrasonic vibration of about 1 kW is applied to the immersion layer, and the laminated substrate 180 is placed on the immersion layer for 10 seconds to 10 seconds. Immerse and wash within minutes. In the post-cleaning step, cleaning is preferably performed a plurality of times. In the initial cleaning, cleaning is performed under the above-described conditions. In the final cleaning, pure water and KOH, NH ₄ OH, or a surfactant are not added. Cleaning may be performed while applying ultrasonic vibration using hydrogen water containing only dissolved hydrogen. The laminated substrate 180 that has been post-cleaned is preferably quickly dried by a spin method or the like.

  Next, a lubricant is applied to the laminated substrate 180 that has been post-cleaned (step 105), and the lubricating layer 170 is formed on the laminated substrate 180. Subsequently, the laminated substrate 180 coated with the lubricating layer 170 is baked by heating at about 100 ° C. for several minutes (step 106). Thereby, moisture contained in the lubricating layer 170 is volatilized, and adhesion between the protective layer 160 provided on the outermost surface side of the laminated substrate 180 and the lubricating layer 170 in contact with the protective layer 160 is increased. Thus, the magnetic recording medium 1 is obtained.

  Next, the surface of the baked magnetic recording medium 1 is wiped (step 107). The wiping process is performed in order to wipe off spatter dust and the like adhering to the surface of the magnetic recording medium 1. As described above, this is because the post-cleaning process in step 104 is performed by immersing in hydrogen water, and it is difficult to remove the powdery substance firmly attached to the surface of the magnetic recording medium 1 by itself. Because.

  The wiping step is performed using, for example, a cloth wiping tape, and the surface of the wiping tape is moved on the surface of the magnetic recording medium 1 by a rubber contact roll or pad while the wiping tape is moved relative to the surface of the magnetic recording medium 1. The surface of the magnetic recording medium 1 is lightly wiped by being pressed against the surface. By performing such processing, sputter dust and the like adhering to the surface of the magnetic recording medium 1 are removed. As a result, when the obtained magnetic recording medium 1 is incorporated in the magnetic recording / reproducing apparatus shown in FIG. 1, the flying height of the magnetic head 3 with respect to the magnetic recording medium 1 can be further reduced.

  Here, as the wiping tape used in the wiping step, a wiping tape obtained by slitting a cloth made of ultrafine fibers into a strip shape, a woven or knitted fabric of ultrafine fiber multifilament yarn, or the like is used.

  Moreover, the wiping method of the magnetic recording medium 1 using such a wiping tape is specifically the surface of the wiping tape (on the magnetic layer side of the magnetic recording medium 1 while rotating the magnetic recording medium 1). This is done by pressing the wiping surface. Thereby, the sputter dust etc. on the surface of the magnetic recording medium 1 are wiped off, and the surface is cleaned. Here, the wiping tape is stretched between the supply reel and the take-up reel, is sequentially supplied from the supply reel, and is taken up by the take-up reel. In the middle of running from the supply reel side to the take-up reel side, the wiping tape is pressed against the wiping surface (back surface) by a backing roll such as rubber or felt, and the wiping surface is magnetically recorded. It is pressed against the surface of the medium 1.

Then, the wiping is performed on the surface of the magnetic recording medium 1 (step 108).
The burnishing step is a step of polishing the surface using a polishing tape in order to remove protrusions formed or attached to the surface of the magnetic recording medium 1. By performing such processing, the flying height of the magnetic head 3 with respect to the magnetic recording medium 1 can be further reduced when the obtained magnetic recording medium 1 is incorporated in the magnetic recording / reproducing apparatus shown in FIG. Further, in the magnetic transfer process described later, a gap is generated between the magnetic recording medium 1 and the master information recording body 200, the transfer pattern becomes unclear, and the master information recording body 200 can be prevented from being damaged.

  The burnishing process is performed using a polishing tape or the like coated with alumina abrasive grains, and the surface of the magnetic recording medium 1 is lightened by pressing the polishing tape against the surface of the magnetic recording medium 1 with a rubber contact roll. This is done by polishing. By performing such processing, abnormal protrusions and the like on the surface of the magnetic recording medium 1 are removed.

  As a polishing tape (burnish tape) used in the burnishing process, a tape formed by forming an abrasive layer on a polyester base film is usually used. Then, when this abrasive layer slides in contact with the magnetic layer side surface of the magnetic recording medium 1, minute dust adhering to the surface of the magnetic recording medium 1 is removed and exists on the surface. Abnormal protrusions and the like are polished and removed, and the surface is smoothed. As an abrasive, chromium oxide, α-alumina, silicon carbide, nonmagnetic iron oxide, diamond, γ-alumina, α, γ-alumina, fused alumina, corundum, artificial, having an average particle size of about 0.05 μm to 50 μm Diamond or the like is used.

  Further, the burnishing of the magnetic recording medium 1 using such a polishing tape is specifically performed by rotating the magnetic recording medium 1 and grinding the polishing tape on the surface of the magnetic recording medium 1 on the magnetic layer side. This is done by pressing the grain surface. Thereby, the protrusions on the surface of the magnetic recording medium 1 are removed by polishing and smoothed. Here, the polishing tape is stretched between the supply reel and the take-up reel, is sequentially supplied from the supply reel, and is taken up by the take-up reel. In the course of running from the supply reel side to the take-up reel side, the polishing tape has its surface (back surface) opposite to the abrasive grain surface pressed by a backing roll such as rubber or felt, and the polishing surface of the polishing tape. Is pressed against the surface of the magnetic recording medium 1.

Next, initial magnetization is performed on the burnished magnetic recording medium 1 (step 109). In this example, since the target is the magnetic recording medium 1 used in the perpendicular recording method, the initial magnetization step is performed by applying an initial DC magnetic field in one direction perpendicular to the surface of the magnetic recording medium 1.
The details of the initial magnetization process will be described later.

Thereafter, a surface inspection is performed on the magnetic recording medium 1 on which the initial magnetization has been performed (step 110). In the surface inspection step, the presence or absence of dust adhesion or abnormal protrusion on the surface of the magnetic recording medium 1 after the initial magnetization is inspected.
Then, magnetic transfer is performed on the magnetic recording medium 1 whose surface inspection has been completed (step 111), and a positioning data storage area A2 (see FIG. 3) in which the servo pattern is stored in the magnetic recording medium 1 is provided.

  Subsequently, a glide inspection is performed on the magnetic recording medium 1 on which the magnetic transfer has been performed (step 112). In the glide inspection process, the head is actually lifted and inspected for the presence of protrusions on the surface of the magnetic recording medium 1 that has been magnetically transferred. When writing (recording) and reading (reproducing) data on the magnetic recording medium 1 using the magnetic head 3, the flying height (the distance between the magnetic recording medium 1 and the magnetic head 3) or more is increased on the surface of the magnetic recording medium 1. If there is a protrusion having a height, the magnetic head 3 may collide with the protrusion and damage the magnetic head 3 or cause a defect in the magnetic recording medium 1. For this reason, in the glide inspection, the presence or absence of such a high protrusion is inspected.

Next, a certification test is performed on the magnetic recording medium 1 that has passed the glide test (step 113). In the certification inspection step, as in a normal magnetic recording / reproducing apparatus, after a predetermined signal is recorded on the magnetic recording medium 1 by the magnetic head 3, the recorded signal is reproduced, and the obtained reproduced signal is used for magnetic recording. The recording failure of the recording medium 1 is detected, and the quality of the magnetic recording medium 1 such as the electrical characteristics of the magnetic recording medium 1 and the presence or absence of defects is confirmed. Since the servo pattern has already been written on the magnetic recording medium 1 manufactured by the above-described method, it is difficult to perform a certifying test by a conventional method that does not use servo information. For this reason, in the present embodiment, the magnetic head 3 is positioned at a specific location using a servo pattern (positioning data) magnetically transferred to the magnetic recording medium 1, and a test for reading and writing data is performed.
Then, the magnetic recording medium 1 that has passed the certification inspection is shipped as a product.

Now, the initial magnetization process in step 109 described above will be described in more detail.
FIG. 5 is a diagram showing an example of the configuration of the initial magnetization apparatus 80 used in the initial magnetization process.
The initial magnetizing device 80 is inserted into the inner end 1a of the burnished magnetic recording medium 1, and a spindle 81 that rotatably supports the magnetic recording medium 1, and the magnetic recording medium 1 via the spindle 81 in the direction of the arrow. And a spindle motor 82 for rotationally driving. Here, the magnetic recording medium 1 is detachable from the spindle 81, and is fixed to the spindle 81 when mounted on the spindle 81.

The initial magnetizing device 80 has a concave section and a core 83 disposed so as to face one surface and the other surface of the magnetic recording medium 1 supported by the spindle 81, and the core 83 is wound around the core 83. A turned coil 84, an AC power supply 85 that supplies an AC current, a DC power supply 86 that supplies a DC current, and a switching unit 87 that switches between supplying AC current, supplying DC current, and whether to supply power to the coil 84. Further prepare. The initial magnetization device 80 further includes a controller 88 that controls the spindle motor 82 and the switching unit 87 described above.
Here, the coercive force Hc of the perpendicular recording layer 150 (the first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155) in the magnetic recording medium 1 is usually 320 kA / m (about 4000 Oe) or more. Yes. Therefore, in the initial magnetization device 80, it is necessary to generate a saturation magnetic flux density of about 3 Tesla capable of direct current magnetization or alternating current magnetization of each magnetic layer of the perpendicular recording layer 150. In addition, it is preferable that the processing speed of the initial magnetization apparatus 80 is about several seconds per sheet from the viewpoint of securing the productivity of the magnetic recording medium 1.

  Of these, the core 83 is made of a magnetically permeable material such as iron. The core 83 includes an upper base 83a located above the magnetic recording medium 1 in the figure, a lower base 83b located below the magnetic recording medium 1 in the figure, and the magnetic recording medium 1 in the figure. It has a connection base material 83c which is located outside the outer end 1b and connects the upper base material 83a and the lower base material 83b. The upper base 83a and the lower base 83b both extend along the radial direction of the magnetic recording medium 1 attached to the spindle 81, and are opposed to each other with the magnetic recording medium 1 in between. The coil 84 described above is wound around the connection base material 83 c of the core 83.

FIG. 6 is a flowchart showing an example of the initial magnetization process performed by the initial magnetization apparatus 80.
First, the inner end 1a of the magnetic recording medium 1 subjected to varnishing is fitted and fixed to the spindle 81 provided in the initial magnetization device 80. Then, both surfaces of the magnetic recording medium 1 are sandwiched between the upper base material 83a and the lower base material 83b of the core 83 provided in the initial magnetization device 80, and the state shown in FIG. 5 is obtained.

  When the attachment of the magnetic recording medium 1 to the spindle 81 and the positioning of the core 83 with respect to the magnetic recording medium 1 after the attachment are completed, the controller 88 starts driving the spindle motor 82 (step 201). Subsequently, the controller 88 starts power supply to the coil 84 by the AC power supply 85 via the switching unit 87 (step 202). Thereafter, the controller 88 determines whether or not the magnetic recording medium 1 has rotated a predetermined number of times after the start of the supply of alternating current (step 203). If a negative determination (N) is made in step 203, the controller 88 returns to step 203 and continues processing. On the other hand, when an affirmative determination (Y) is made in step 203, the controller 88 ends the power supply to the coil 84 by the AC power supply 85 via the switching unit 87 (step 204). In the following description, steps 202 to 204 are referred to as “alternating current magnetization process”.

Next, the controller 88 starts power supply to the coil 84 by the DC power supply 86 via the switching unit 87 (step 205). Thereafter, the controller 88 determines whether or not the magnetic recording medium 1 has rotated a predetermined number of times after the start of the supply of the direct current (step 206). If a negative determination (N) is made in step 206, the controller 88 returns to step 206 and continues processing. On the other hand, when an affirmative determination (Y) is made in step 206, the controller 88 ends the power supply to the coil 84 by the DC power source 86 via the switching unit 87 (step 207). Then, the controller 88 ends the driving of the spindle motor 82 after the end of the supply of the direct current (step 208), and the initial magnetization process for one magnetic recording medium 1 is completed. In the following description, steps 205 to 207 are referred to as “DC magnetization process”.
Here, the coercive force Hc of the perpendicular recording layer 150 (the first magnetic layer 151, the second magnetic layer 153, and the third magnetic layer 155) in the magnetic recording medium 1 of the present embodiment is typically 320 kA / m (about 4000 Oe). ) That's it. Therefore, in the direct current magnetization process, it is preferable to select a direct current value to be supplied to the coil 84 so that each magnetic layer of the perpendicular recording layer 150 can be subjected to direct current magnetization.

Then, the magnetic recording medium 1 that has undergone the initial magnetization process including the AC magnetization process and the DC magnetization process is removed from the spindle 81 and sent to the next process (surface inspection process).
Note that the number of times that is a criterion for determination in step 203 and step 206 is not limited as long as it is at least one rotation or more. Further, the specified number of times in step 203 and the specified number of times in step 206 may be different from each other. The rotational speed of the magnetic recording medium 1 is preferably 50 to 800 rpm, and the polarity reversal period of the core 83 in the AC magnetization process is preferably 50 to 1000 Hz. This polarity reversal period is much lower than the frequency of AC magnetization (AC erase) by the conventional magnetic head.

  FIG. 7 is a diagram schematically showing the state of the perpendicular recording layer 150 of the magnetic recording medium 1 in each process of the initial magnetization process. Here, FIG. 7A illustrates a state before the AC magnetization process is executed, and FIG. 7B is a state after the AC magnetization process is executed and the DC magnetization process is executed. The previous state is illustrated, and FIG. 7C illustrates the state after the AC magnetization process and the DC magnetization process are executed.

  In the film forming process of step 103 described above, the state of the perpendicular recording layer 150 to be formed varies with variations in various conditions. In particular, in the state immediately after film formation (so-called as-depo), the magnetization direction in the perpendicular recording layer 150 may be biased in a specific region. In the example shown in FIG. 7A, in the perpendicular recording layers 150 formed on both sides of the magnetic recording medium 1, the in-plane distribution of the respective magnetization directions is biased.

  In the present embodiment, an AC magnetization process (step 202 to step 204) is performed on the magnetic recording medium 1 that has undergone the burnish process as an example of a demagnetization process that applies an AC magnetic field for one or more rounds. Then, in the magnetic recording medium 1, the direction of magnetization in the perpendicular recording layer 150 is sequentially changed by the applied AC magnetic field, and for example, as shown in FIG. The bias is eliminated, and a random orientation state is brought about with demagnetization.

  In the present embodiment, a DC magnetization process (steps 205 to 207) in which a DC magnetic field is applied over one or more rounds is performed on the magnetic recording medium 1 that has undergone the AC magnetization process. Then, in the magnetic recording medium 1, the direction of magnetization in the perpendicular recording layer 150 is directed in one direction by the DC magnetic field applied in the first direction. For example, as shown in FIG. , The respective magnetization directions are aligned in one direction.

  In the conventional demagnetization process (DC magnetization process), as shown in FIG. 7A, DC magnetization is performed in a state where the magnetization bias is large. However, the direct current magnetization process needs to be completed in a short time of about several seconds in order to increase the productivity of the magnetic recording medium 1, and the direct current magnetization process shown in FIG. In some cases, the magnetization state could not be completely achieved on the entire magnetic recording surface of the magnetic recording medium 1. In the present invention, as described above, since the magnetization state of the magnetic recording medium 1 is first set to a random state as shown in FIG. 7B, direct current magnetization is performed, so that the magnetization of FIG. It becomes possible to be in a state.

  Next, the magnetic transfer process of step 111 performed after the above-described initial magnetization process will be described in detail.

  FIG. 8 is a cross-sectional view showing an example of the configuration of the magnetic transfer device 14 used in the magnetic transfer process, and FIG. 9 is a perspective view schematically showing the configuration of the magnetic transfer device 14. FIG. 10 is a diagram showing an example of the configuration of the master information recording body 200 used in the magnetic transfer device 14. Here, FIG. 10A shows a top view of the master information recording body 200, and FIG. 10B shows an XB-XB sectional view of FIG. 10A.

  As shown in FIGS. 8 and 9, the magnetic transfer device 14 is mounted in a fixed state on a base (not shown), and a master information recording body 200 on which a servo pattern is magnetically recorded is fixed. The fixed holder 30 to be held and the fixed holder 30 are arranged so as to be opposed to the fixed holder 30 and can be moved to the side approaching the fixed holder 30 and the side away from the fixed holder 30, and the servo pattern is magnetically recorded in advance. And a movable holder 40 that holds the master information recording body 200 in a fixed state. Note that the master information recording body 200 attached to the fixed holder 30 and the master information recording body 200 attached to the movable holder 40 are arranged in a state of facing each other.

  A first magnet member 50 including a first magnet 51 is disposed on the back side of the fixed holder 30 that holds the master information recording body 200. The first magnet member 50 includes a first magnet 51 disposed opposite to the fixed holder 30, a first magnet holding part 52 that holds the first magnet 51, and a first magnet that extends from the back side of the first magnet holding part 52. And a support portion 53. The first magnet support portion 53 is supported in a state of being fixed in the horizontal direction in the drawing and is rotatably supported in the arrow direction in the drawing. Thereby, the 1st magnet 51 hold | maintained at the 1st magnet holding | maintenance part 52 rotates with the rotation of the 1st magnet support part 53. As shown in FIG.

  On the other hand, a second magnet member 60 including a second magnet 61 is disposed on the back side of the movable holder 40 holding the master information recording body 200. The second magnet member 60 includes a second magnet 61 disposed to face the movable holder 40, a second magnet holding part 62 that holds the second magnet 61, and a second magnet that extends from the back side of the second magnet holding part 62. And a support part 63. The second magnet support portion 63 is supported so as to be able to advance and retreat in the horizontal direction in the figure, and is supported so as to be rotatable in the arrow direction in the figure. As a result, the second magnet 61 held by the second magnet holding part 62 advances and retreats as the second magnet support part 63 advances and retreats, and the second magnet holding part 62 changes as the second magnet support part 63 rotates. The second magnet 61 held by the motor rotates.

In the first magnet member 50, the first magnet 51 is attached to the first magnet holding portion 52 in a radial direction at a position deviated from the rotation center of the first magnet support portion 53. Further, the first magnet 51 is held by the first magnet holding portion 52 so that the side facing the fixed holder 30 is a magnetic pole of one polarity (for example, N pole).
On the other hand, in the second magnet member 60, the second magnet 61 is attached to the second magnet holding portion 62 in a radial direction at a position deviated from the rotation center of the second magnet support portion 63. The second magnet 61 is held by the second magnet holding unit 62 so that the side facing the movable holder 40 is a magnetic pole of the other polarity (for example, S pole).

  And in this Embodiment, the 1st magnet 51 and the 2nd magnet 61 are arrange | positioned so that the fixed holder 30 and the movable holder 40 may be pinched | interposed. Moreover, the 1st magnet member 50 and the 2nd magnet member 60 are comprised so that it may rotate together, maintaining the state which made the 1st magnet 51 and the 2nd magnet 61 oppose.

  A master information recording body 200 shown in FIG. 10 has a disk shape whose diameter is larger than that of the magnetic recording medium 1. Also, a servo pattern formation region SP in which fine irregularities corresponding to the servo pattern are formed is provided on one surface of the master information recording body 200. In this example, a plurality of servo pattern formation regions SP are provided radially on one surface of the master information recording body 200 except for the central portion and the outer edge portion. When the master information recording body 200 is attached to the fixed holder 30 or the movable holder 40 shown in FIG. 8, the surfaces provided with the servo pattern formation regions SP face each other in an exposed state.

  In addition, a first through hole 200a and a second through hole 200b penetrating the front and back are provided in the central portion of the master information recording body 200 attached to the fixed holder 30. The first through hole 200a and the second through hole 200b are provided on the inner side (center side) of the servo pattern formation region SP in the master information recording body 200. Note that the first through hole 200 a and the second through hole 200 b are not necessary for the master information recording body 200 attached to the movable holder 40. The reason for this will be described later.

  Next, the structure of the master information recording body 200 as an example of the pattern forming body will be described. The master information recording body 200 includes a disc-shaped base 201 and a master magnetic layer 202 formed on one surface of the base 201. And a master protective layer 203 formed on the master magnetic layer 202. Here, FIG. 10B shows a cross-sectional configuration of the master information recording body 200 in the servo pattern formation region SP, and there are convex portions 204 and concave portions 205 corresponding to the servo pattern at this portion. ing. Of the one surface of the master information recording body 200, an area other than the servo pattern formation area SP is a recess in the servo pattern formation area SP in order to prevent the master information recording body 200 and the magnetic recording medium 1 from being attracted. It is the same height as 205.

  The master information recording body 200 can be manufactured by a known method. For example, the following manufacturing method can be listed. First, an electron beam resist is applied to the surface of a silicon wafer by a spin coat method. After coating, the resist is exposed by irradiating the resist with an electron beam modulated in accordance with the servo pattern using an electron beam exposure apparatus. Thereafter, the resist is developed, unexposed portions are removed, and a resist pattern is formed on the silicon wafer.

  Next, using this resist pattern as a mask, a reactive etching process is performed on the silicon wafer to dig up portions not masked with the resist. After this etching process, the resist remaining on the silicon wafer is removed by washing with a solvent. Thereafter, the silicon wafer is dried to obtain a master for producing the master information recording body 200.

  On this master, a conductive layer made of Ni is formed to a thickness of about 10 nm by sputtering. Thereafter, a Ni layer having a thickness of several μm is formed on the master by electroforming using the master on which the conductive layer is formed as a mother die. Thereafter, the Ni layer is removed from the master, and this Ni layer is washed to obtain the base body 201 having the convex portions on the surface.

Next, a master magnetic layer 202 is formed on the surface of the substrate 201. As the master magnetic layer 202, the same magnetic layer (first magnetic layer 151 and the like) used in the magnetic recording medium 1 can be used. A master protective layer 203 is formed on the master magnetic layer 202 in the same manner as the magnetic recording medium 1. The master protective layer 203 increases the abrasion resistance of the master information recording body 200, that is, the transfer durability of the master information recording body 200, and a hard carbon film having a thickness of about several nm can be used. The master information recording body 200 can be obtained by the above manufacturing process.
The master information recording body 200 thus obtained is repeatedly used for manufacturing (magnetic transfer) of, for example, 100,000 or more magnetic recording media 1.

  Further, as shown in FIG. 8, the fixed holder 30 penetrates the holding surface of the master information recording body 200 and the facing surface of the first magnet member 50, and master information recording is performed on the holding surface of the master information recording body 200. The master information recording body 200 passes through the two first suction paths 31 provided with an opening at the center of the attachment position of the body 200, the holding surface of the master information recording body 200, and the facing surface of the first magnet member 50. And two second suction paths 32 having openings provided outside the attachment position of the master information recording body 200 on the holding surface. Further, the fixed holder 30 includes an O-ring 33 attached along the circumferential direction on the holding surface of the master information recording body 200 outside the opening of the second suction path 32. In addition, when the master information recording body 200 is attached to the fixed holder 30 in the two openings of the first suction path 31 on the holding surface of the master information recording body 200 of the fixed holder 30, The first through hole 200a and the second through hole 200b are overlapped.

  On the other hand, the movable holder 40 holds the master information recording body 200 on the surface facing the fixed holder 30, and the recording body holding portion 40a provided with the second magnet member 60 on the back side thereof, And a cylindrical body 40b provided so as to cover the periphery of the recording body holding portion 40a. In addition, the movable holder 40 includes an O-ring 41 that is attached along the circumferential direction to the inner circumferential surface of the cylindrical body 40b and that contacts the outer circumferential surface of the recording body holding portion 40a over the circumferential direction. Here, the recording body holding portion 40a and the cylindrical body 40b constituting the movable holder 40 are attached to the fixed holder 30 so as to be able to advance and retract independently of each other. Further, the end of the cylindrical body 40b on the side facing the fixed holder 30 faces and contacts the O-ring 33 provided on the fixed holder 30 over one circumference. Note that the recording member holding portion 40 a of the movable holder 40 is not provided with a suction path like the fixed holder 30. For this reason, it is not necessary to provide the first through hole 200a and the second through hole 200b in the master information recording body 200 attached to the recording body holding portion 40a.

  Now, the magnetic transfer process by the magnetic transfer device 14 will be described with reference to FIGS. The magnetic transfer device 14 is supplied with the magnetic recording medium 1 that has been subjected to the initial magnetization through the initial magnetization process in step 109 and subjected to the surface inspection in the surface inspection process in step 110. To do. In the following description, the magnetic recording medium 1 before execution of the magnetic transfer process is referred to as “pre-transfer medium”, and the magnetic recording medium 1 after execution of the magnetic transfer process is referred to as “transferred medium”.

  As the operation starts, the pre-transfer medium is transported by a transport mechanism (not shown) to an area sandwiched between the master information recording body 200 attached to the fixed holder 30 and the master information recording body 200 attached to the movable holder 40. Come. Then, the pre-transfer medium is stopped in a state where it is conveyed to a position facing the master information recording body 200 held by the fixed holder 30, and positioning with respect to the master information recording body 200 is performed.

  After the pre-transfer medium stops, suction through the first suction path 31 is started, and the pre-transfer medium is chucked on the fixed holder 30 side. At this time, one surface of the pre-transfer medium comes into contact with the master information recording body 200 attached to the fixed holder 30. Thereafter, the holding of the pre-transfer medium by the transport mechanism is released, and the transport mechanism is retracted.

  Subsequently, the movable holder 40 (recording body holding part 40a, cylindrical body 40b) and the second magnet member 60 start moving toward the fixed holder 30 side. Along with this, first, the peripheral end surface of the cylindrical body 40 b stops after abutting against the O-ring 33 provided in the fixed holder 30. Further, the recording body holding part 40a and the second magnet member 60 continue to move toward the fixed holder 30 side even after the cylindrical body 40b stops, and the master information recording body 200 provided in the fixed holder 30 The recording medium holding unit 40a of the movable holder 40 is stopped after the pre-transfer medium is sandwiched between the master information recording body 200 and the master information recording body 200. The stop position of the recording body holding unit 40a is determined in advance, and as a result, a preset light load is applied to the two master information recording bodies 200 and one pre-transfer medium. At this time, an O-ring 33 provided on the fixed holder 30 and an O-ring 41 provided on the cylindrical body 40b are used between the fixed holder 30, the recording body holding portion 40a, and the cylindrical body 40b. Thus, a closed space is formed. Subsequently, when the suction through the second suction path 32 is started, a gap existing between the two master information recording bodies 200 existing in the closed space and the one pre-transfer medium is evacuated. Then, due to the differential pressure inside and outside the closed space, the formation surface of each servo pattern formation region SP of the two master information recording bodies 200 and the both surfaces of one pre-transfer medium are brought into close contact with each other.

  Next, the first magnet member 50 and the second magnet member 60 have the first magnet support portion 53 and the second magnet support portion 63 as axes, and the two master information recording bodies 200 and one pre-transfer medium. At least one rotation is performed while maintaining the state where the first magnet 51 and the second magnet 61 are opposed to each other. While the first magnet 51 and the second magnet 61 make one rotation, in the pre-transfer medium sandwiched between the two master information recording bodies 200, the direct current magnetization process in the initial magnetization process is performed by the first magnet 51 and the second magnet 61. A direct-current magnetic field in the second direction, which is opposite to the first, is sequentially applied in the circumferential direction.

  FIG. 11 is a diagram schematically showing the state of the perpendicular recording layer 150 of the magnetic recording medium 1 before and after passing through the first magnet 51 and the second magnet 61. 11A shows a state before passing through the first magnet 51 and the second magnet 61, that is, after initial magnetization, and FIG. 11B shows a state after passing through the first magnet 51 and the second magnet 61, that is, magnetic transfer. Each subsequent state is illustrated.

  As shown in FIG. 11, on the side of the pre-transfer medium that is in contact with the master information recording body 200 on the fixed holder 30 side, the magnetization of the perpendicular recording layer 150 at a portion facing the concave portion 205 of the master information recording body 200. Although the orientation maintains the state after the initial magnetization process, the orientation of magnetization of the perpendicular recording layer 150 at the portion in contact with the convex portion 204 is reversed. In addition, on the side of the pre-transfer medium that is in contact with the master information recording body 200 on the movable holder 40 side, the magnetization direction of the perpendicular recording layer 150 at the portion facing the recess 205 of the master information recording body 200 is the initial magnetization step. Although the later state is maintained, the magnetization direction of the perpendicular recording layer 150 at the portion in contact with the convex portion 204 is reversed. In this way, the servo patterns made up of the concave / convex arrangement provided on the master information recording body 200 are transferred onto both surfaces of the pre-transfer medium as servo patterns made up of the magnetization orientation arrays. As a result, the pre-transfer medium is a transferred medium having the servo pattern stored in the positioning data storage area A2.

  When the magnetic transfer is completed in this way, first, the suction through the second suction path 32 is stopped to make the inside of the closed space atmospheric pressure, and then the movable holder 40 (recording body holding portion 40a, cylindrical body 40b). Then, the second magnet member 60 starts to retract to the original position. As a result, the transferred medium held by the fixed holder 30 is exposed to the outside. Thereafter, after the transferred medium is held by a transport mechanism (not shown), the suction through the first suction path 31 is stopped, and the transferred medium is moved outside the area where the fixed holder 30 and the movable holder 40 are opposed to each other by the transport mechanism. It is conveyed to.

  As described above, in the present embodiment, in the initial magnetization process, since direct current magnetization is performed on the magnetic recording medium 1 after performing alternating current magnetization, direct current magnetization is performed (initial magnetization is performed). In the magnetic recording medium 1, it is possible to reduce the region where the magnetization is reversed with respect to the target direction. In the present embodiment, servo pattern recording is performed on the magnetic recording medium 1 subjected to such initial magnetization by performing magnetic transfer using the master information recording body 200. It is possible to suppress erroneous information from remaining in the pattern formation region SP.

  In this embodiment, AC magnetization and DC magnetization in the initial magnetization process are performed in a non-contact manner with the target magnetic recording medium 1. Thereby, the cleanliness of the surface of the magnetic recording medium 1 in the initial magnetization process can be maintained, and the occurrence of a situation in which the magnetic recording medium 1 is rubbed and damaged in the initial magnetization process can be avoided.

In the present embodiment, AC magnetization and DC magnetization are performed on the magnetic recording medium 1 by using one initial magnetizing device 80, but the present invention is not limited to this. The magnetization process may be performed by separate devices.
In the present embodiment, both AC magnetization and DC magnetization for the magnetic recording medium 1 are performed using an electromagnet. However, the present invention is not limited to this. For example, for DC magnetization, a permanent magnet is used. You can do it.

(Manufacture of magnetic recording media)
A cleaned glass substrate 100 (manufactured by Konica Minolta, 2.5 inch outer diameter) is housed in a film forming chamber of a DC magnetron sputtering apparatus (C-3040 manufactured by Anelva), and the ultimate vacuum is 1 × 10 ^−3. After the inside of the deposition chamber was evacuated to ⁵ Pa, an adhesion layer 110 having a layer thickness of 10 nm was deposited on the substrate 100 using a 60Cr-40Ti target. Further, on this adhesion layer 110, a target of 46Fe-46Co-5Zr-3B {Fe content 46 atomic%, Co content 46 atomic%, Zr content 5 atomic%, B content 3 atomic%} is used. Then, a first soft magnetic layer 121 having a layer thickness of 34 nm is formed at a substrate temperature of 100 ° C. or lower, and a spacer layer 122 made of Ru is formed thereon with a layer thickness of 0.76 nm, and then 46Fe-46Co is further formed. A −5Zr-3B second soft magnetic layer 123 was formed to a thickness of 34 nm to obtain a soft magnetic underlayer 120.

  Next, on the soft magnetic underlayer 120, Ni-6W {W content 6 atom%, remaining Ni} target and Ru target were sequentially formed with a layer thickness of 5 nm and 20 nm, respectively. The orientation control layer 130 was obtained.

Then, on the orientation control layer 130, as the perpendicular recording layer 150 of the multilayer structure, 84 (Co12Cr16Pt) -16TiO ₂ (film thickness _{3nm), 91 (Co5Cr22Pt) -4SiO} 2 -3Cr 2 O 3 -2TiO 2 ( film 3 nm thick), Ru47.5Co (film thickness 0.5 nm), and Co15Cr16Pt6B (film thickness 3 nm) were stacked.
Next, a protective layer 160 made of carbon having a layer thickness of 2.5 nm was formed by a CVD method to obtain a laminated substrate 180.

The laminated substrate 180 manufactured by the above method was washed with hydrogen water. Washing is composed of three stages of washing processes. The washing tank used in each washing process is made of SUS, has a volume of 20 liters, and 500 W ultrasonic vibration is applied to the inside. In each washing tank, 15 liters of hydrogen water having a dissolved hydrogen concentration of 1.5 ppm and an oxidation-reduction potential of −550 mV produced using ultrapure water is added. Further, 0.1 ppm of KOH is added to the first washing tank. did. The laminated substrate 180 was immersed in this three-stage cleaning tank in order and cleaned for 30 seconds in each cleaning tank. The laminated substrate 180 after cleaning was quickly pulled up using dry air and dried.
A lubricating layer 170 made of perfluoropolyether was formed to a thickness of 15 angstroms on the surface of the laminated substrate 180 by dipping, whereby the magnetic recording medium 1 was obtained.

  A wiping process was performed on the magnetic recording medium 1 coated with the lubricant. As the wiping tape, a peelable composite fiber having a wire diameter of 2 μm made of nylon resin and polyester resin was used. In the wiping process, the rotational speed of the magnetic recording medium 1 was 300 rpm, the feeding speed of the wiping tape was 10 mm / second, the pressing force when pressing the wiping tape against the magnetic recording medium 1 was 98 mN, and the processing time was 5 seconds. In the wiping treatment, perfluoropolyether was sprayed on the wiping tape to form a lubricant layer of about 0.01 μm on the tape surface.

  The magnetic recording medium 1 subjected to the wiping process was burnished. The burnish tape used was a polyethylene terephthalate film on which crystal growth type alumina particles having an average particle size of 0.5 μm were fixed with an epoxy resin. In the burnishing, the rotational speed of the magnetic recording medium 1 was 300 rpm, the polishing tape feed speed was 10 mm / second, the pressing force when pressing the polishing tape against the magnetic recording medium 1 was 98 mN, and the processing time was 5 seconds.

  The magnetic recording medium 1 subjected to burnish processing was subjected to alternating current magnetization, and then subjected to initial magnetization by direct current magnetization. Specifically, it was performed on both data surfaces of the magnetic recording medium 1 by the process shown in FIG. 6 using the apparatus used in FIG. The alternating current magnetization step is 100 rpm, the polarity reversal period of the electromagnet is 200 Hz, the magnetic field penetrating the magnetic recording medium 1 is 10 kOe, the alternating magnetization time is 3 seconds, and the direct current magnetization step is the magnetic recording medium. The rotational speed of 1 was 100 rpm, the magnetic field penetrating the magnetic recording medium 1 was 10 kOe, and the DC magnetization time was 3 seconds.

(Preparation of master information recording medium)
The master information recording body 200 is formed with a pattern such as a servo signal of 271 k tracks / inch, the track T has a width of 120 nm, the width between the tracks T is 60 nm, and the step of the pattern is 45 nm. In the master information recording body 200, a Ru film having a thickness of 10 nm is formed on a Ni substrate 201 constituting a convex portion by using a DC sputtering method, and a 70Co-5Cr-15Pt having a thickness of 20 nm as a master magnetic layer 202. A −10 SiO ₂ alloy film, an 80Co-5Cr-15Pt alloy film with a layer thickness of 15 nm, and a CVD carbon film with a layer thickness of 20 nm as the master protective layer 203 were laminated in this order.

(Magnetic transfer process)
Magnetic transfer was performed on the magnetic recording medium 1 subjected to initial magnetization using the master information recording body 200 and the magnetic transfer device 14 having the structure shown in FIG. During magnetic transfer, the master information recording body 200 was brought into close contact with both data surfaces of the magnetic recording medium 1 with a pressure of 98 mN, and a DC magnetic field for transfer was applied from the back surface of the master information recording body 200. The intensity of the DC magnetic field at this time was 4 kOe, and the transfer time was 3 seconds.

  The servo signal reproduction characteristics of the magnetic recording medium 1 manufactured by the above method were measured using a read / write analyzer (model number: RWA1632; manufactured by GUZIK, USA) and a spin stand (model number: S1701MP). In this apparatus, a servo signal or the like recorded on the magnetic recording medium 1 is read, and the magnetic head can be positioned using this signal. At this time, a magnetic head using TuMR (Tunneling Magneto-Resistive) was used as the magnetic head for evaluation, and the S / N ratio at the time of servo signal reading was evaluated. For servo signal reading, 20 tracks were evaluated at equal intervals from the innermost track T to the outermost track T of the magnetic recording medium 1, and the average value was obtained. As a result, the S / N ratio of the magnetic recording medium 1 of the example was 16.5 dB.

<Comparative example>
The magnetic recording medium 1 was manufactured and magnetic transfer was performed in the same manner as in the example, but AC magnetization was not performed in the initial magnetization process, and only DC magnetization was performed. The magnetic recording medium 1 was read and evaluated in the same manner as in the example. The S / N ratio was 16.1 dB.

DESCRIPTION OF SYMBOLS 1 ... Magnetic recording medium, 14 ... Magnetic transfer apparatus, 80 ... Initial magnetization apparatus, 81 ... Spindle, 82 ... Spindle motor, 83 ... Core, 84 ... Coil, 85 ... AC power supply, 86 ... DC power supply, 87 ... Switching part, DESCRIPTION OF SYMBOLS 88 ... Controller, 100 ... Board | substrate, 110 ... Adhesion layer, 120 ... Soft magnetic underlayer, 130 ... Orientation control layer, 140 ... Nonmagnetic underlayer, 150 ... Perpendicular recording layer, 160 ... Protective layer, 170 ... Lubrication layer, 180 DESCRIPTION OF SYMBOLS ... Laminated substrate 200 ... Master information recording body 201 ... Base | substrate 202 ... Master magnetic layer 203 ... Master protective layer 204 ... Convex part 205 ... Concave part

Claims (6)

Applying an alternating magnetic field to a magnetic recording medium having a magnetic layer laminated on a substrate;
Applying a DC magnetic field in a first direction to the magnetic recording medium to which the AC magnetic field is applied;
A DC magnetic field in a second direction opposite to the first direction is applied to the magnetic recording medium to which the DC magnetic field in the first direction is applied in contact with a pattern forming body on which a pattern is formed. And a step of applying the magnetic recording medium. In the step of applying the alternating magnetic field, the alternating magnetic field is applied to the magnetic recording medium in a non-contact manner,
2. The method of manufacturing a magnetic recording medium according to claim 1, wherein, in the step of applying a DC magnetic field in the first direction, a DC magnetic field is applied to the magnetic recording medium in a non-contact manner. The magnetic layer is composed of information recorded by a perpendicular recording method,
In the step of applying the alternating magnetic field, the alternating magnetic field is applied in a direction perpendicular to the surface of the magnetic layer,
In the step of applying the direct current magnetic field in the first direction, the direct current magnetic field in the first direction is applied in a direction perpendicular to the surface of the magnetic layer,
3. The magnetic recording according to claim 1, wherein in the step of applying the DC magnetic field in the second direction, the DC magnetic field in the second direction is applied in a direction perpendicular to the surface of the magnetic layer. A method for manufacturing a medium. Demagnetizing the magnetic layer in the magnetic recording medium having the magnetic layer laminated on the substrate;
Orienting the magnetization direction of the magnetic layer in the magnetic recording medium demagnetized in one direction,
And a step of locally orienting the magnetization direction of the magnetic layer in the magnetic recording medium in which the magnetic layer is oriented in the one direction in a direction opposite to the one direction. The magnetic layer is composed of information recorded by a perpendicular recording method,
5. The method of manufacturing a magnetic recording medium according to claim 4, wherein in the step of orienting the magnetization direction of the magnetic layer in the one direction, the one direction is a direction perpendicular to the surface of the magnetic layer. Demagnetizing the magnetic layer in the magnetic recording medium having the magnetic layer laminated on the substrate;
Aligning the magnetization direction of the magnetic layer in the magnetic recording medium with the magnetic layer demagnetized in one direction.

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