JP2010272191A - Method for manufacturing magnetic recording medium and device for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that incident ions are concentrated in an acute angle part such as an end surface of a magnetic disk substrate to be worked, abnormal discharge called arcing is generated and breakage of a magnetic film is generated in a separation region formation working of a discrete track medium by an ion injection molding. <P>SOLUTION: A high voltage pulse 32 is applied to an electrode structure wherein a grid 30 having a potential equal to that of a magnetic disk substrate to be worked (substrate to be worked) 20 is provided on an upper surface of an electrode plate 44 on which the substrate to be worked is held. Thereby, a high voltage sheath 41 is formed only on the surface of the grid and no sheath is formed on the surface of the substrate to be worked enclosed by the grid to suppress arcing. The area of the electrode plate except a part covered by the substrate to be worked is made to be equal to or larger than the area of the substrate to be worked disposed on the electrode plate exposed to ions radiated through the grid and to positively utilize secondary electrons and thus non-damaged ion injection working is performed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a pattern medium typified by a discrete track medium and a bit pattern medium suitable for high recording density, and more particularly to a method and an apparatus for forming a track guide separation area.

  In recent years, the increase in capacity and performance of magnetic recording / reproducing apparatuses have been accelerated rapidly due to the increase in the amount of information used in personal computers and the expansion of applications to video recording equipment, car navigation systems, and the like. In the background, the adoption of a perpendicular magnetic recording system that has no thermal fluctuation in a high recording density region and has a stable reproduction output, and the use of a tunnel magnetoresistive element greatly contribute. Here, in the perpendicular magnetic recording system, small unit magnets arranged vertically on the surface of the magnetic recording medium have a structure in which they are separated in advance by a nonmagnetic material contained in the magnetic film.

  Currently, as a proposal to more actively control this separation area and improve the magnetic recording density, a discrete track medium in which separation processing is performed between the disk tracks, and a bit pattern medium in which separation processing is also performed in the recording bit direction. In both cases, the separation zone forming technique is an important point for increasing the recording density. For example, in a discrete track medium, a substrate processing type in which a concave and convex shape is formed in advance on a substrate as a separation region forming processing technique, and a magnetic film is formed thereon, thereby forming a concave and convex magnetic film. In addition, a magnetic film processing mold has been proposed in which a concave and convex shape is formed by applying a resist to a magnetic film and etching a portion to be a concave portion. However, in these techniques, the recess is backfilled with a nonmagnetic material, and the surface thereof is flattened according to the height of the magnetic film to be the protrusion, and a protective film is formed on the flattened surface. By having process steps, new problems such as increased foreign matter and surface roughness on the surface of the magnetic film and the protective film occur, and a magnetic head that is another point for increasing the recording density Narrowing the gap (nano spacing) of the magnetic disk is hindered.

  As a means for solving these problems, a processing method that can obtain the same effect magnetically without forming an uneven shape has been attempted. As described in Patent Document 1 and Patent Document 2, a nonmagnetic or soft magnetized region is formed by applying a resist to a magnetic film formed as usual and performing ion implantation in a portion to be a recess. Is an ion implantation type. If this method is used, it is said that none of the concave portion formation, the concave portion backfilling, and the surface flattening are required, and good flying characteristics and magnetic characteristics can be obtained as a magnetic disk device.

  Patent Document 3 discloses that when an inorganic film forming material is deposited on a glass substrate by arc discharge while moving the glass substrate in a vacuum chamber in the horizontal direction, ions are accelerated with respect to an insulating substrate such as a glass substrate. In order to prevent charge-up that would be a problem when performed, it is described that a grid made of fine metal wires or the like is provided on the arc source side of the glass substrate.

Japanese Patent Laying-Open No. 2004-164692 (see paragraphs 0138-0142 and FIG. 10) JP 2002-288813 A JP-A 63-203760

  The problem to be solved by the present invention relates to an ion implantation type which is one of the prior arts. In the ion implantation type processing method, it is necessary to perform ion implantation having an energy of about several keV to several tens keV in order to form a non-magnetic or soft magnetic region. In this case, as clarified by experiments by the inventors, for example, when ion implantation is performed on a magnetic disk substrate to be processed in which a magnetic film having a film thickness of several tens of nanometers is formed on a glass substrate, incident ions are changed. There is a problem that it concentrates on an acute angle portion such as the end surface of the magnetic disk substrate to be processed, an abnormal discharge called arcing occurs, and the magnetic film of the magnetic disk substrate to be processed is broken. This phenomenon occurs because the electric field due to the potential gradient (sheath) generated on the surface of the magnetic disk substrate to be processed during ion implantation is concentrated on an acute angle surface such as the end surface of the magnetic disk substrate to be processed. Occurs and causes substrate damage. The probability of occurrence of this arcing phenomenon increases when a sufficient current path cross-sectional area cannot be secured as the ion current path on the magnetic disk substrate to be processed, or as the ions have higher energy.

  As another cause of arcing, there is a case where the charge is locally increased due to charge-up on the surface of the insulator and reaches the breakdown voltage. Therefore, it may occur even on the resist film surface having a pattern made of an insulator.

The feature of the present invention is the electrode structure and process as means for preventing arcing, which is the above problem.
That is, a representative method of manufacturing a magnetic recording medium according to the present invention includes a step of forming at least a magnetic film on at least one surface of a substrate, and forming a substrate to be processed by forming a resist film having an uneven pattern on the magnetic film. And a method of irradiating ions from the direction of the resist film and demagnetizing or softening a portion of the magnetic film corresponding to the concave portion of the resist film. The ions are supplied to an equipotential space formed between an electrode plate on which the substrate to be processed having the same potential is disposed and a grid disposed to face the electrode plate and the substrate to be processed. It is characterized by that.

  In the method for manufacturing the magnetic recording medium, it is preferable that the ions supplied to the equipotential space are directly supplied from plasma formed on the upstream side of the grid.

  In the method for manufacturing the magnetic recording medium, a portion covered by the substrate to be processed is excluded with respect to an area of the substrate to be processed which is disposed on an electrode plate exposed to ions irradiated through the grid. It is desirable that the area of the electrode plate is at least equal to or larger.

  In particular, the area of the electrode plate excluding the portion covered with the substrate to be processed is preferably 1 to 6 times the area of the substrate to be processed.

  In the method of manufacturing the magnetic recording medium, it is preferable that the grid is composed of a plurality of sheets.

  In the method of manufacturing the magnetic recording medium, the step of demagnetizing or softening the magnetic film may be performed by applying a pulse voltage that changes between a negative voltage and a ground or between a positive voltage and a ground according to the type of the ions. It is desirable that the process be performed while applied to both the substrate to be processed and the grid.

  In the method for manufacturing the magnetic recording medium, when a metal atom is used as the ion species, it is preferably a metal atom selected from Cr, Mn, or V.

In the method for manufacturing the magnetic recording medium, when the ionic species is generated as a gas, it is desirable that the gas used includes at least one atom or molecule of Ar, N ₂ , Ne, O ₂ or F.

  In the method for manufacturing the magnetic recording medium, the substrate is preferably made of glass or silicon.

  In the method of manufacturing the magnetic recording medium, it is preferable that the magnetic film forming step includes a step of forming a laminated film of a base film and a soft magnetic film on the substrate prior to the formation of the magnetic film.

  In the method of manufacturing the magnetic recording medium, after the step of demagnetizing or softening the magnetic film, further removing the resist film, forming a protective film on the magnetic film, It is desirable to include a step of forming a lubricating film on the protective film.

The following two apparatuses can be given as typical apparatus for producing a magnetic recording medium of the present invention.
The first includes a plasma generation source for generating plasma by arc discharge, a processing chamber, and a plasma transport section for guiding the plasma of the plasma generation source into the processing chamber, and at least a magnetic film on both surfaces of the substrate. A magnetic recording medium in which a substrate to be processed in which a resist film having a concavo-convex pattern is formed on the magnetic film is installed in the processing chamber, and both surfaces of the substrate to be processed are irradiated with ions in the plasma A substrate holder for holding the substrate to be processed is disposed in the processing chamber at a position facing the plasma transport portion, and the substrate is interposed between the plasma transport portion and the substrate holder. A grid having the same potential as the holder is arranged, and a pulse voltage generator for applying a pulse voltage to the substrate holder and the grid is connected.

  In the magnetic recording medium manufacturing apparatus, the area of the substrate holder that is irradiated with the ions through the grid is equal to or larger than the area of the substrate to be processed that is also irradiated with the ions. Is desirable.

  In particular, the area of the substrate holder irradiated with the ions is preferably 1 to 6 times the area of the substrate to be processed.

  In the magnetic recording medium manufacturing apparatus, the grid is preferably composed of a plurality of sheets.

  Second, a vacuum chamber, a gas introduction section for introducing gas into the vacuum chamber, plasma is generated by glow discharge in the vacuum chamber, and is disposed on both surfaces of the substrate disposed in the vacuum chamber. An apparatus for manufacturing a magnetic recording medium, wherein both surfaces of a magnetic film and a substrate to be processed on which a resist film having a concavo-convex pattern is formed are irradiated with ions in the plasma and processed. A substrate holder for holding the substrate to be processed is disposed at a position facing the plasma in the vacuum chamber, and a grid having the same potential as the substrate holder is disposed between the plasma and the substrate holder, A pulse voltage generator for applying a pulse voltage to the substrate holder and the grid is connected.

  In the magnetic recording medium manufacturing apparatus, after the glow discharge is generated in a pulsed manner by high-frequency power applied to the substrate to be processed and the grid, before the ions in the glow discharge disappear, It is desirable to have means for applying a pulse voltage to the substrate and the grid.

  In the magnetic recording medium manufacturing apparatus, the area of the substrate holder that is irradiated with the ions through the grid is equal to or larger than the area of the substrate to be processed that is also irradiated with the ions. Is desirable.

  In particular, the area of the substrate holder irradiated with the ions is preferably 1 to 6 times the area of the substrate to be processed.

  In the magnetic recording medium manufacturing apparatus, the grid is preferably composed of a plurality of sheets.

  According to the present invention, when a discrete track medium and a bit pattern medium are patterned by an ion implantation method, arcing that occurs on the magnetic disk substrate to be processed can be suppressed, and an undamaged ion implantation process can be performed.

FIG. 5 is a process diagram of a method for manufacturing a magnetic recording medium according to Example 1. 1 is a conceptual diagram of an apparatus for irradiating a metal ion on one side of a magnetic disk substrate to be processed according to Embodiment 1. FIG. It is a conceptual diagram about components, such as a grid of a metal ion irradiation apparatus shown in FIG. 2, and a to-be-processed magnetic disk board | substrate. FIG. 3 is a conceptual diagram simulating shapes of a grid, a processed magnetic disk substrate, and an electrode plate of the metal ion irradiation apparatus shown in FIG. 2. It is a figure which shows the measurement result of the ion implantation amount based on Example 1, and magnetic write width Mww (Magnetic write width). It is a figure which shows the measurement result of the ion implantation amount based on Example 1, and the retention strength Hc. It is a figure which shows the measurement result of the ion implantation amount based on Example 1, and the magnetization amount Ms. 6 is a conceptual diagram of a device for irradiating metal ions to both surfaces of a magnetic disk substrate to be processed according to Embodiment 3. FIG. It is the conceptual diagram which simulated the shape of the grid of the metal ion irradiation apparatus shown in FIG. 8, a to-be-processed magnetic disk substrate, and a substrate holder. FIG. 10 is a conceptual diagram of a gas ion irradiation apparatus for one surface of a magnetic disk substrate to be processed according to a fourth embodiment. It is a figure which shows the measurement result of the ion implantation amount based on Example 4, and the magnetic write width Mww. It is a figure which shows the measurement result of the ion implantation amount based on Example 4, and the retention strength Hc. It is a figure which shows the measurement result of the ion implantation amount based on Example 4, and the magnetization amount Ms. FIG. 10 is a conceptual diagram of a gas ion irradiation device for both surfaces of a magnetic disk substrate to be processed according to Example 6; FIG. 10 is a conceptual diagram of a gas ion irradiation apparatus on both surfaces of a magnetic disk substrate to be processed according to a modification of Example 6; It is a figure which shows the measurement result of the ratio of the area of a to-be-processed magnetic disk substrate, the area of an electrode plate except the part covered with the to-be-processed magnetic disk substrate, and the generation probability of arcing. It is the photograph figure which performed MFM measurement after magnetizing to a magnetic disk medium. It is a conceptual diagram about electrode components, such as a three grid by Example 8, and a to-be-processed magnetic disk board | substrate. It is a conceptual diagram about the electrode component of the to-be-processed magnetic disk board | substrate of the comparative example 1 which does not apply this invention. It is an optical microscope photograph figure of the to-be-processed magnetic disk board | substrate damaged by arcing.

  The first feature of the present invention is that the magnetic disk substrate to be processed is disposed on the electrode plate, the grid is disposed opposite to the electrode plate and the magnetic disk substrate to be processed, and the electrode plate and the grid have the same potential. In contrast, by applying a high voltage pulse, a high voltage sheath is formed only on the grid surface, and a sheath is formed on the surface of the magnetic disk substrate to be processed surrounded by the grid and the electrode plate having the same potential as the grid. Not to suppress arcing. The second feature is that the electrode excluding the portion covered by the magnetic disk substrate to be processed with respect to the area of the magnetic disk substrate to be processed disposed on the electrode plate exposed to the ions irradiated through the grid. By making the area of the plate equal to or greater than that, the secondary electrons are actively used to perform an undamaged ion implantation process. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a process diagram showing a method of manufacturing a magnetic recording medium according to the first embodiment.
Referring to FIG. 1 (a), a substrate obtained by chemically strengthening the surface of borosilicate glass or aluminosilicate glass was used as the substrate 1 after being washed and dried. Instead of a chemically strengthened glass substrate, a substrate that has been surface-polished after Ni-P plating on an aluminum alloy substrate or a rigid substrate made of Si or Ti alloy can also be used.

  A 50 at.% Al-50 at.% Ti alloy layer as the adhesion layer 2 is 5 nm and the first soft magnetic layer 3 is 51 at.% Fe-34 at.% Co-10 at.% Ta-5 at. % Zr alloy layer 15 nm, antiferromagnetic coupling layer 4 Ru layer 0.5 nm, second soft magnetic layer 5 51 at.% Fe-34 at.% Co-10 at.% Ta-5 at.% Zr alloy layer 15 nm The under layer 6 has a 50 at.% Cr-50 at.% Ti alloy layer of 2 nm, the first orientation control layer 7 has a 94 at.% Ni-6 at.% W alloy layer of 7 nm, and the second orientation control layer 8 has a Ru layer. 17 nm, 59 mol.% Co-16 mol.% Cr-17 mol.% Pt-8 mol.% SiO2 alloy layer 9 nm as the first magnetic layer 9, 63 at.% Co-15 at.% Cr-14 at. % Pt-8at.% B alloy layers were sequentially laminated to 2 nm.

  The film formation of each of the above layers was carried out using a sheet-type sputtering apparatus capable of transporting the substrate in a vacuum and continuously forming a plurality of layers as described above. An alloy target having the same composition as the desired film composition was prepared and sputtered to form the alloy layer as described above. The Ar gas pressure at the time of film formation was set to 1 Pa when layers other than the second orientation control layer 8 and the first magnetic layer 9 were formed. The Ar gas pressure for forming the second orientation control layer 8 was such that the lower side 9 nm of the second orientation control layer 8 was formed at 1 Pa and the upper side 8 nm was formed at 5 Pa. During film formation of the first magnetic layer 9, oxygen was added to Ar. Each partial pressure was set to 4 Pa for Ar and 0.2 Pa for oxygen.

  After applying the resist to the medium formed through the above steps, the concave / convex pattern is transferred to the resist by pressing a stamper on which the concave / convex pattern similar to the shape of the recording track and servo area is formed, and the track pitch is 120 nm. A resist film 11 having a width of 60 nm and a height of 150 nm was formed. Note that the resist residue 12 is also present in the track separation region 13 by about 20 nm. The entire substrate on which the resist film 11 having the concavo-convex pattern has been formed is referred to as a processed magnetic disk substrate (processed substrate) 20.

After the resist film is formed, the medium is irradiated with Cr ions as the nonmagnetic element ions 14, and as shown in FIG. 1B, the first magnetic layer 9 and the second magnetic layer 10 are partially non-tracked as a track separation region 15. A portion having a high content of the magnetic element Cr was formed. In this example, as described above, Cr ions having the strongest effect of reducing the magnetization of the Co-based alloy serving as the magnetic layer were used. This is because the Co and d band energy orders are close to each other, so that electronic transition is likely to occur, and the Co upspin band is effectively filled. Similar effects can be obtained with V ions and Mn ions in addition to Cr ions. Here, the acceleration voltage for ion irradiation needs to be a condition that at least the resist residue 12 has a thickness of 20 nm and can be easily penetrated, and the resist film 11 has a thickness of 150 nm and ions cannot penetrate. In this embodiment, since all are positive ions, a negative acceleration voltage must be applied. However, in the case of negative ions, it is needless to say that a positive acceleration voltage must be applied. As an element that generates negative ions, there is a gas containing O ₂ or F.

FIG. 2 shows a conceptual diagram of an ion irradiation apparatus for performing the process of FIG. In this embodiment, a plasma beam 31 generated by the arc discharge unit 21 is used as an ion source. Details will be described below. The plasma beam 31 is generated from an arc discharge unit 21 arranged so as to be processed on one side of the magnetic disk substrate 20 to be processed. Specifically, a voltage is applied between the cathode 22 and the anode 23 made of Cr to generate an arc discharge 25 in a high vacuum atmosphere. The cathode 22 is in a very high temperature state, similar to arc welding, and generates plasma from the cathode surface. The term “plasma” as used herein refers to a state in which Cr ions 14 and electrons 26 are generated in a vacuum with a gas pressure of 10 ⁻⁴ Pa or less. Further, an arc current of about 100 A was introduced into the cathode 22 to generate an arc discharge with an arc voltage of about -20V. The generated Cr ions 14 and electrons 26 enter a processing chamber 28 that holds the magnetic disk substrate 20 to be processed through a curved magnetic duct 27 that removes droplets generated during arc discharge and transports plasma. The magnetic disk substrate 20 to be processed is uniformly irradiated by the scanning electromagnet 29. Since the plasma beam 31 is neutral as a whole, it is irradiated with Cr ions 14 and electrons 26, and is irradiated onto the grid 30 installed on the top of the magnetic disk substrate 20 to be processed.

  FIG. 3 is a conceptual diagram of the components of the electrode plate 44 on which the grid 30 and the magnetic disk substrate 20 to be processed in FIG. 2 are held. In this figure, with respect to an equipotential space 38 formed between the electrode plate 44 on which the magnetic disk substrate 20 to be processed is disposed and the grid 30 disposed above (upstream side), −20 kV, −5 A The negative voltage and the pulse voltage 32 that changes with the ground are applied at a duty ratio of 80% and a frequency of 40 kHz. Therefore, for a pulse width of 25 μs, intermittent acceleration voltage application is performed under the conditions of a pulse application time of 20 μs and a stop time of 5 μs. The high voltage pulse power supply 24 used was a maximum of -50 kV, -50 A. The frequency of the high-voltage pulse power supply 24 is 40 kHz, but in preliminary experiments, a study is conducted from 1 kHz to 50 kHz. Here, since the unit time per pulse changes if the frequency is different, it goes without saying that there is an optimum pulse duty ratio depending on each frequency. In addition, the pulse duty ratio is useful for reducing overheating associated with ion implantation, and is a design matter that also depends on the thickness of the magnetic layer constituting the magnetic disk substrate 20 to be processed. Furthermore, this pulse duty ratio also depends on the performance of the high voltage pulse power supply 24 used in the experiment. At least, when metal ions are used, if the pulse duty ratio is less than 50%, metal ions are not implanted. It should be noted that efficient ion implantation is not possible because it results in deposition on the surface of the magnetic layer that is the target.

  In addition, as shown in FIG. 4, the area of the electrode plate 44 excluding the portion covered with the magnetic disk substrate 20 to be processed is 1.5 times the area of the magnetic disk substrate 20 to be irradiated with ions. did. The grid 30 is made of a Mo material having a thickness of 1 mm, and is made up of a plurality of through holes 33. The diameter of the through hole 33 is 4 mm, and it is spaced from the adjacent through hole 33 by about 1 mm. The distance 34 between the grid 30 and the magnetic disk substrate 20 to be processed was 50 mm. Of course, the material of the grid 30 may be general W, C, or the like. Further, the hole diameter of the through-hole 33 is a design matter based on the relationship between the grid 30 and the distance 34 between the magnetic disk substrate 20 to be processed, and is most suitable for the magnetic disk substrate 20 to be processed while maintaining the object of the present invention. What is necessary is just to select the through-hole diameter which can perform a uniform process. Further, for example, there is no problem even if a mesh-structured grid 30 using a Mo wire having a diameter of about 100 μm is used. In addition, it is needless to say that the ion implantation process can be uniformly performed on the magnetic disk substrate 20 to be processed by adding the rotational motion mechanism to the grid 30 relative to the magnetic disk substrate 20 to be processed.

  3 shows a potential distribution 35 in the processing chamber 28. On the surface of the grid 30, a high-voltage sheath 41 is formed with a potential difference of about −20 kV between the plasma potential 36 and the pulse voltage 37. The ions 14 in the plasma beam 31 are accelerated by the sheath 41 and enter the equipotential space 38 surrounded by the electrode plate 44 on which the grid 30 and the magnetic disk substrate 20 to be processed are arranged. Since all the equipotential spaces 38 are equipotential surfaces, no electric field is basically generated. Therefore, electric field concentration on an acute angle portion such as the end surface of the magnetic disk substrate to be processed does not occur, and arcing can be prevented. However, on the surface of the grid 30 in contact with the plasma beam 31 side, the electric field concentrates on an acute angle portion such as the end face of the grid through hole 33, and the probability of occurrence of arcing 39 due to ion collision increases.

  In addition, the ions 14 incident on the magnetic disk substrate 20 to be processed have a charge of one or more valences, and the surface of the magnetic disk substrate 20 to be processed is covered with a resist material serving as an insulator. There was no arcing from dielectric breakdown. This will be described in detail with reference to Example 7, but the area of the electrode plate 44 excluding the portion covered with the magnetic disk substrate 20 to be processed with respect to the area of the magnetic disk substrate 20 to be processed irradiated with ions, This is considered to be the generation effect of the secondary electrons 42 obtained from the 1.5 times.

With the above electrode structure and process conditions, Cr ions 14 are irradiated onto the magnetic disk substrate 20 to be processed at about 1 × 10 ^{16 to} 12 × 10 ¹⁶ ions / cm ² , and mainly the first magnetic layer 9. Then, the track separation region 15 was produced by ion implantation into the second magnetic layer 10.

  During this irradiation process, arcing 39 was confirmed on the surface of the grid 30 at the initial stage of ion irradiation, but no arcing occurred on the surface of the magnetic disk substrate 20 to be processed, and no damage was confirmed. . That is, it was confirmed that the electrode structure of the present invention was effective.

  Now, after forming the track separation region 15 by ion implantation (FIG. 1B), as shown in FIG. 1C, the resist film 11 and the resist residue 12 are formed by RIE (Reactive ion etching) using oxygen. As shown in FIG. 1 (d), a DLC (Diamond-like Carbon) protective film 16 having a thickness of 2 nm is formed by CVD, and a lubricant mainly composed of perfluoroalkyl polyether is applied to the thickness. A 1 nm lubricating film 17 was formed. As the DLC protective film, a carbon protective film by sputtering or CVD, or ta-C (tetrahedral amorphous carbon) formed using a cathodic arc method having an ion transport mechanism by a magnetic field filter can be used.

  Next, the magnetic write width Mww (Magnetic write width) of the created discrete track medium 18 was evaluated using a spin stand. A magnetic head having a reproducing track width Twr (Track width of reader) of 50 nm and a writing width Tww (Track width of writer) of 70 nm was used.

The results are shown in FIG. 5. In FIG. 5, the horizontal axis represents the Cr injection amount, and the vertical axis represents the write width Tww. The Mww was about 90 nm when the amount of Cr injected was 1.3 × 10 ¹⁶ ion / cm ² , whereas the Mww was greatly reduced to about 70 nm in the region where the amount injected was 6.5 × 10 ¹⁶ ion / cm ² or more, almost constant. As a result, it was confirmed that the track width can be narrowed and the track density can be greatly improved.

In order to confirm the cause of the change in Mww, a sample not subjected to resist patterning was prepared in the above process, and the holding force Hc and the magnetization amount Ms were measured with a vibrating sample magnetometer. The results are shown in FIGS. 6 and 7, respectively. According to this result, the holding force Hc rapidly decreases with the amount of ion implantation, and is nearly zero at 3.9 × 10 ¹⁶ ions / cm ² . On the other hand, the magnetization amount Ms is almost 0 at 6.5 × 10 ¹⁶ ions / cm ² , and it can be seen that the relationship between the implantation amount and Mww in FIG. That is, the result of FIG. 5 shows that when the composition ratio of Cr, which is a nonmagnetic atom implanted into the track separation region 15, is a certain ion implantation amount (9.1 × 10 ¹⁶ ions / cm ^{2 in} this embodiment) or more. This indicates that the amount of magnetization is almost 0, and the magnetic coupling between the tracks forms a region where the tracks can be sufficiently separated.

  Discrete track medium 18 was prepared in the same manner as in Example 1 except that the ions 14 to be irradiated in Example 1 were changed from Cr ions, which are nonmagnetic elements, to other metal elements. As nonmagnetic elements, Mn and V were studied. The experiment was conducted using the electrode structure shown in FIGS. 2, 3, and 4 as in Example 1.

  By the way, the ions 14 irradiated to the magnetic layer of the magnetic disk substrate 20 to be processed are intermittently implanted into the magnetic film at the acceleration voltage and pulse frequency applied by the high voltage pulse power source 24. The penetration depth is determined by the type and energy of ions, the relationship with the magnetic film (here, the first magnetic layer 9 and the second magnetic layer 10) that is the target to be irradiated, that is, the nuclear stopping power.

  In this embodiment, the target to be irradiated is the same, and it is necessary to consider the acceleration voltage depending on the atomic number of the ion 14 (the number of protons in the nucleus) and the atomic mass. Therefore, prior to this example, the ion penetration depth itself has an ideal distribution for the alloy layer 9 nm of the first magnetic layer 9 and the alloy layer 2 nm of the second magnetic layer 10 in consideration of the distribution in the depth direction. Preliminary study was conducted to perform ion implantation that can be made non-magnetic or soft magnetic.

  As a result, it has been found that having the maximum value of the distribution in the vicinity of the intermediate depth position of the first magnetic layer 9 from the intermediate depth position of the second magnetic layer 10 is most effective for demagnetization or soft magnetism. . In this experiment, the depth analysis by micro-Auger electron spectroscopy of each sample and the energy dispersive X-ray spectroscopic analysis of cross-sectional transmission electron images and the holding force Hc and magnetization amount Ms obtained by a vibrating sample magnetometer Derived from the measurement results. In order to implant ions most efficiently at this ideal penetration depth, it was found that both Mn and V, including Cr, were -20 kV in terms of acceleration voltage. The reason why it did not depend on the metal species is that all samples had the same atomic number and atomic mass. However, this optimum acceleration voltage depends on the thickness of the magnetic film layer as a target and the components on the magnetic film.

  As a result of the above-mentioned preliminary examination, both Mn and V including Cr are equipotentials formed between the electrode plate 44 and the magnetic disk substrate 20 to be processed and the grid 30 disposed thereabove. An experiment was performed by applying a negative voltage of −20 kV and a pulse voltage 32 changing with the ground at a duty ratio of 80% and a frequency of 40 kHz to the space. However, as in Example 1, the area of the electrode plate 44 excluding the portion covered with the magnetic disk substrate 20 to be processed was 1.5 times the area of the magnetic disk substrate 20 to be processed with ions. .

As a result, no arcing occurred on the surface of the magnetic disk substrate 20 to be processed and no damage was observed at an injection amount of about 1 × 10 ^{16 to} 12 × 10 ¹⁶ ions / cm ² . That is, it was confirmed that the electrode structure of the present invention was effective. However, some arcing was confirmed only on the surface of the grid 30 in the initial stage of ion irradiation.

Next, Mww was evaluated using the same head as in Example 1. Although there was some variation, each element had an Mww of about 90 nm at 1.3 × 10 ¹⁶ ions / cm ² , whereas the injection amount However, in the region of 6.5 × 10 ¹⁶ ions / cm ² or more, the Mww was greatly reduced to about 70 nm. Thus, it was confirmed that the track density can be greatly improved by narrowing the track width. As described above, it was confirmed that the track density equivalent to that in Example 1 was obtained by setting the implantation amount of each element to 6.5 × 10 ¹⁶ ions / cm ² or more.

  Incidentally, in order to increase the recording density, it is necessary to reduce the thickness of the magnetic films (here, the first magnetic layer 9 and the second magnetic layer 10). On the other hand, there is a limit to reducing the thickness of the magnetic film. As a magnetic film capable of at least obtaining the current characteristics, when the first magnetic layer 9 is Xnm, the second magnetic layer 10 is Ynm, and the total film thickness is Znm, (X, Y, Z) = (9, 2 , 11), (8, 2, 10), (7, 2, 9), (6, 2, 8), (5, 2, 7), (4, 2, 6), (3, 2, 5 ), (2, 2, 4), (9, 1, 10), (8, 1, 9), (7, 1, 8), (6, 1, 7), (5, 1, 6), For the combination of (4, 1, 5), (3, 1, 4), (2, 1, 3), the result is an effective film configuration as a magnetic film. Among these film thickness configurations, the minimum film thickness was 3 nm, and the lower limit of the acceleration voltage for performing the treatment targeted by the present invention by metal ion irradiation was −3 kV.

  Therefore, the acceleration voltage for performing the treatment intended by the present invention on the magnetic film having a total film thickness of 3 to 11 nm by metal ion irradiation is preferably in the range of −3 kV to −20 kV.

  FIG. 2 is a model intended for processing on one side of the magnetic disk substrate 20 to be processed, but FIG. 8 shows an ion irradiation apparatus for performing the process of the present invention on both surfaces of the magnetic disk substrate 20 to be processed. A conceptual diagram is shown. FIG. 9 is a conceptual diagram showing components of the metallic substrate holder 47 on which the grid 30 and the magnetic disk substrate 20 to be processed are held. The magnetic disk substrate 20 to be processed is a substrate holder attached to the substrate holder 47. The member 48 holds the processed magnetic disk substrate 20 at three positions on the end surface. Here, since the resist is not attached to the end surface of the magnetic disk substrate 20 to be processed, the metal substrate holder 47 and the metal film formed on the magnetic disk substrate 20 to be processed sufficiently obtain electrical continuity. Can do. Further, the gap generated between the substrate holder 47 and the magnetic disk substrate 20 to be processed is about 1 mm. It is desirable that this gap be as narrow as possible to prevent mutual interference of ions 14 irradiated on both surfaces of the magnetic disk substrate 20 to be processed and for stable ion implantation. Furthermore, the area of the opposite surface of the substrate holder 47 exposed to the ions 14 through the grid 30 on both sides is 1.5 times the area of the opposite surface of the magnetic disk substrate 20 to be processed exposed to the ions 14. It is said. Since the magnetic disk substrate 20 to be processed has an opening at the center portion, an insulating cap is provided by a cap support member 46 connected to the center of the grid 30 in order to prevent interference on both sides through this portion. 45 is arranged on both sides. The gap between the insulator cap 45 and the opening end face of the central portion of the magnetic disk substrate 20 to be processed is about 1 mm.

  As a result of performing double-sided simultaneous processing using the same process conditions as in Example 1 using this electrode structure, the discrete track medium 18 created on both sides of the magnetic disk substrate 20 to be processed was implemented on both sides. The same result as that of the single-side treated product shown in Example 1 could be obtained.

  A discrete track medium 18 was prepared in the same manner as in Example 1 by changing the irradiated ions 14 in FIG. Unlike the case where Cr, Mn, V, which are non-magnetic metal ions, obtain demagnetization characteristics from the modification of the crystal structure, in the case of gas elements, the magnetic film crystal structure is destroyed to make it amorphous, thereby making it soft magnetic. Furthermore, it can be made almost non-magnetic by optimizing the medium structure and film thickness (thinning) and chemical reaction with the medium.

In this example, the results when N ₂ gas is used will be described. FIG. 10 shows a conceptual diagram of a gas ion irradiation apparatus for performing the process of FIG. Here, 100 W of electric power is supplied from a high frequency (RF) power source 72 to the parallel plate electrode 71 in the vacuum chamber 70, and a glow discharge 74 is generated from the mass flow meter 73 with N ₂ at 10 sccm and a gas pressure of 0.6 Pa. was a N ₂ ⁺ and N ⁺ ions 14 consisting of an ion source. The detailed mechanism around the electrode plate 44 holding the grid 30 and the magnetic disk substrate 20 to be processed in FIG. 10 is basically the same as in the first embodiment, and the ion generation is performed in the arc discharge unit in the first embodiment. It can be considered that the plasma beam 31 generated by 21 is a glow discharge 74 and is changed from Cr ⁺ to N ₂ ⁺ and N ⁺ . However, with regard to the accelerating voltage, the experiment was conducted at -15 kV in consideration of the fact that the implantation depth increases because the mass of the ion species is different from Cr ⁺ . That is, a negative voltage of −15 kV and a pulse voltage that changes depending on the ground are applied to an equipotential space 38 formed between the magnetic disk substrate 20 to be processed and the grid 30 and electrode plate 44 disposed above it, with a duty ratio of 80%, An experiment was conducted by applying at 40 kHz. Further, the area of the electrode plate 44 excluding the portion covered by the magnetic disk substrate 20 to be processed was 1.5 times the area of the magnetic disk substrate 20 to be processed irradiated with ions.

According to the experimental results, at the implantation amount of about 1 × 10 ^{16 to} 5 × 10 ¹⁶ ions / cm ² , no arcing occurred on the surface of the magnetic disk substrate 20 to be processed, and no damage was confirmed. That is, it was confirmed that the electrode structure of the present invention was effective. Also on the surface of the grid 30, arcing was confirmed only about 1/10 of the frequency when using metal atoms. This is considered to be caused by a difference in kinetic energy due to the small atomic mass of gas ions compared to metal ions.

Next, Mww was evaluated using the same head as in Example 1. As shown in FIG. 11, Mww of about 70 nm was achieved at about 5 × 10 ¹⁶ ions / cm ² .

Next, a sample not subjected to resist patterning in the above process was prepared, and the holding force Hc and the magnetization amount Ms were measured with a vibrating sample magnetometer. The results are shown in FIGS. 12 and 13, respectively. According to this result, both the coercive force Hc and the magnetization amount Ms decrease almost linearly as the ion implantation amount increases, and the coercive force Hc and the magnetization amount Ms are both nearly zero at about 5 × 10 ¹⁶ ions / cm ² . showed that.

  From the above results, it was confirmed that even when the gas element was used, the magnetic coupling between the tracks formed a region where the tracks were sufficiently separated.

A discrete track medium 18 was similarly produced by changing N ₂ of Example 4 to another gas element using the experimental apparatus of FIG. Specifically, Ar, Ne, O ₂ , and CF ₄ gases were studied.

  The process conditions in this embodiment are that all gases are supplied with 100 W of high frequency (RF) power 72 to the parallel plate electrode 71 in the vacuum chamber 70, and each gas is supplied from the mass flow meter 73 to 10 sccm. A glow discharge 74 was generated at a pressure of 0.6 Pa to provide an ion source. Further, the area of the electrode plate 44 excluding the portion covered by the magnetic disk substrate 20 to be processed was 1.5 times the area of the magnetic disk substrate 20 to be processed irradiated with ions.

  In the present embodiment, it is necessary to consider the ion acceleration voltage depending on the atomic number and atomic mass of the irradiated ion element. Therefore, prior to the experiment, while considering that the injection amount itself has a distribution in the depth direction, the ideal soft magnetism or alloying for the alloy layer 9 nm of the first magnetic layer 9 and the alloy layer 2 nm of the second magnetic layer 10 is considered. Preliminary studies were conducted to perform gas ion implantation that can be made non-magnetic.

As a result, having the maximum value of the distribution in the vicinity of the intermediate depth position of the first magnetic layer 9 from around the intermediate depth position of the second magnetic layer 10 can be most effectively non-magnetic or soft magnetic. It was derived from the depth analysis of the sample by micro-Auger electron spectroscopy, energy dispersive X-ray spectroscopic analysis of cross-sectional transmission electron images, and measurement results of coercive force Hc and magnetization Ms obtained with a vibrating sample magnetometer. Then, it was found that for the most efficient injection to this ideal depth, Ne, O ₂ and CF ₄ including N ₂ were all -15 kV. The reason for having the same acceleration voltage is considered to be that the mass was almost the same in the state where these gas elements were ionized. On the other hand, Ar was -18 kV.

Based on the results of the above preliminary studies, the negative voltage of -15kV and -3.8A for Ne, O ₂ and CF _{4 and} -18kV and -4.5A for Ar and the pulse voltage 32 that changes with the ground with a duty ratio of 80%, frequency The experiment was performed by applying at 40 kHz. The high voltage pulse power supply 24 used was a maximum of -50 kV, -50 A.

As a result, no arcing occurs on the surface of the magnetic disk substrate 20 to be processed and any damage is confirmed when any gas is used at an injection amount of about 1 × 10 ^{16 to} 5 × 10 ¹⁶ ions / cm ² . There wasn't. That is, it was confirmed that the electrode structure of the present invention was effective. However, on the surface of the grid 30, the occurrence of a slight arcing was confirmed as in the other examples, and the arcing occurrence rate on the surface of the grid 30 was relatively high particularly when Ar was used.

Next, Mww was evaluated using the same head as in Example 1. With any gas, the Mww was 90 nm or more at 1 × 10 ¹⁶ ion / cm ² , but the injection amount increased. It was confirmed that it decreased with time. However, at an injection amount of 5 × 10 ¹⁶ ions / cm ² , the Mww was 75 nm, and the effect as much as using N ₂ shown in Example 3 was not achieved. In this experiment, each gas atom was used alone, but two gases of Ar, N ₂ , Ne, O ₂ , CF ₄ were used in order to take advantage of each gas element. It is also possible to supply and optimize at the same time.

Incidentally, in order to increase the recording density, it is necessary to reduce the thickness of the magnetic films (here, the first magnetic layer 9 and the second magnetic layer 10). On the other hand, there is a limit to reducing the thickness of the magnetic film. As a magnetic film capable of at least obtaining the current characteristics, when the first magnetic layer 9 is Xnm, the second magnetic layer 10 is Ynm, and the total film thickness is Znm, (X, Y, Z) = (9, 2 , 11), (8, 2, 10), (7, 2, 9), (6, 2, 8), (5, 2, 7), (4, 2, 6), (3, 2, 5 ), (2, 2, 4), (9, 1, 10), (8, 1, 9), (7, 1, 8), (6, 1, 7), (5, 1, 6), For the combination of (4, 1, 5), (3, 1, 4), (2, 1, 3), the result is an effective film configuration as a magnetic film. Among these film thickness configurations, the minimum film thickness is 3 nm, and the lower limit of acceleration voltage in Ne, O ₂ , CF ₄ gas ion implantation including N ₂ is at least an acceleration that can be implanted into the magnetic film 3 nm. We have experimentally determined that a voltage of -1kV is necessary. For Ar, it was −3 kV.

Therefore, for a magnetic film having a total film thickness of 3 to 11 nm, the acceleration voltage for performing the treatment targeted by the present invention by gas ion irradiation using Ar, N ₂ , Ne, O ₂ , CF ₄ is as follows: Preferably, it is in the range of -1 kV to -18 kV.

  As shown in FIG. 10, the experimental apparatus of Examples 4 and 5 was a model intended for processing on one side of the magnetic disk substrate 20 to be processed, but in FIG. 14, the process of the present invention is processed. The conceptual diagram of the gas ion irradiation apparatus for performing on both surfaces of the magnetic disc board | substrate 20 is shown. In this figure, the magnetic disk substrate 20 to be processed is held by a substrate holder 47. The components of the substrate holder 47 on which the grid 30 and the magnetic disk substrate 20 to be processed are held are as shown in the conceptual diagram of FIG. 9, and the magnetic disk substrate 20 to be processed is attached to the substrate holder 47. Are held at three positions on the end surface of the magnetic disk substrate 20 to be processed. Here, since the resist is not attached to the end face of the magnetic disk substrate 20 to be processed, the metal film formed on the substrate holder 47 and the magnetic disk substrate 20 to be processed can sufficiently obtain electrical continuity. Further, the gap generated between the substrate holder 47 and the magnetic disk substrate 20 to be processed is about 1 mm. This gap is preferably as narrow as possible for stable ion implantation. Furthermore, the area of the opposite surface of the substrate holder 47 exposed to the ions 14 through the grid 30 on both sides is 1.5 times the area of the opposite surface of the magnetic disk substrate 20 to be processed exposed to the ions 14. It is said. Since the magnetic disk substrate 20 to be processed has an opening at the center portion, an insulating cap is provided by a cap support member 46 connected to the center of the grid 30 in order to prevent interference on both sides through this portion. 45 is arranged on both surfaces, and the gap between the insulator cap 45 and the opening end face of the magnetic disk substrate 20 to be processed is 1 mm.

  As a result of performing double-sided simultaneous processing under the same process conditions as in Examples 4 and 5, the created discrete track medium 18 was able to obtain the same results as the single-sided processed products shown in Examples 4 and 5. .

  10 and 14, the high voltage pulse source 24 and the ion source are configured as separate electrodes (here, a parallel plate type electrode 71 connected with a high frequency (RF) power source 72). As shown in FIG. 15, a high voltage pulse power source 24 and a high frequency (RF) power source 72 may be connected to the magnetic disk substrate 20 to be processed, the substrate holder 47 and the grid 30. In this case, for example, the power application by the high frequency (RF) power source 72 and the high voltage pulse power source 24 is alternately applied by the switching element 110 or the like. In the experiment, a pulsed RF glow discharge is generated only for 50 μs, and after 2 μs, a negative pulse voltage of −15 kV is applied to the magnetic disk substrate 20 to be processed and the grid 30 disposed thereabove for 20 μs, thereby generating ions generated by the glow discharge. Is introduced into the magnetic disk substrate 20 to be processed before disappearing. And it was set as the repetition conditions of generating pulsed RF glow discharge again after 5 microseconds. Accordingly, assuming that the pulse RF glow discharge and the pulse bias application are one cycle, the repetition frequency is about 13 kHz.

As a result of performing the same experiment as that of Example 4 using the apparatus shown in FIG. 15 in the above procedure, the surface of the magnetic disk substrate 20 to be processed was implanted at an injection amount of about 1 × 10 ^{16 to} 5 × 10 ¹⁶ ions / cm ² No arcing occurred and no damage was observed. That is, it was confirmed that the electrode structure of the present invention was effective. For Mww evaluation, coercive force Hc evaluation, and magnetization amount Ms evaluation, the same results as in Example 4 could be obtained. An advantage of using this electrode structure is simplification of the electrode structure in the vacuum chamber 70.

  In the first to sixth embodiments, the area of the electrode plate 44 excluding the portion covered by the magnetic disk substrate 20 to be processed with respect to the area of the magnetic disk substrate 20 to be processed exposed to ions as shown in FIG. The experiment was conducted with the substrate holder 47 having an area of 1.5 times. In the present embodiment, the results of examining the probability of occurrence of arcing in the magnetic disk substrate 20 to be processed by changing the area ratio will be described.

The electrode structure used in the experiment was the same as that of Example 1 shown in FIG. 2 and FIG. The process condition is that a negative voltage of −20 kV and a ground are used with respect to an equipotential space 38 formed between the electrode plate 44 and the magnetic disk substrate 20 to be processed and the grid 30 disposed above the Cr ions 14. The changing pulse voltage 32 was applied at a duty ratio of 80% and a frequency of 40 kHz, so that the ion implantation amount was about 9.1 × 10 ¹⁶ ions / cm ² .

  FIG. 16 shows the result, and the horizontal axis represents B / when the area of the magnetic disk substrate 20 to be processed is A and the area B of the electrode plate 44 excluding the portion covered by the magnetic disk substrate 20 to be processed. A is shown. According to this result, when B / A is 0, 0.25, 0.5, the electric field concentrates near the end face of the magnetic disk substrate 20 to be processed, and the crack 150 that can be found at the optical microscope level as shown in FIG. 20 occurs. It was. Due to the crack 150, both the metal film and the resist film constituting the magnetic disk substrate 20 to be processed were destroyed.

  When B / A was 0.75, minute arcing was confirmed during the process, but after completion of the process, the occurrence of arcing as shown in FIG. Therefore, in order to observe further details, FIG. 17 shows a photograph of MFM measurement after the sample was magnetized. In the photograph, a physically damaged portion 122 considered to be the influence of arcing occurs in the non-magnetized region 121 in which ions corresponding to the track separation region 13 are implanted with respect to the magnetic film 120 protected by the resist film. I was able to confirm that. That is, it has been found that an undamaged discrete track medium 18 cannot be obtained even if minute arcing occurs.

  On the other hand, B / A is 1 or more (1, 1.5, 3, 6), that is, the area A of the magnetic disk substrate 20 to be processed disposed on the electrode plate 44 exposed to the ions irradiated through the grid 30. On the other hand, when the area B of the electrode plate facing surface excluding the portion covered with the magnetic disk substrate 20 to be processed is equal to or larger than the same, arcing on the surface of the magnetic disk substrate 20 to be processed does not occur, The physically damaged portion 122 did not occur in the non-magnetized region 121 as shown in FIG. However, when B / A was 8 or more (8, 10), minute arcing occurred again. Based on the above results, in Examples 1 to 6, B / A was 1.5 and the experiment was performed.

  By the way, the physical cause of the above result is presumed as follows. That is, the ions 14 incident on the magnetic disk substrate 20 to be processed have a charge of one or more charges, while the surface of the magnetic disk substrate 20 to be processed is covered with a resist material that becomes an insulator. An arcing generation mechanism from dielectric breakdown due to charge-up can be considered. However, when B / A increases, the area of the electrode plate 44 not covered with the resist material increases, and secondary electrons 42 are generated by irradiating the ions 14 there. The secondary electrons 42 perform charge exchange with the ions 14 irradiated to the magnetic disk substrate 20 to be processed, thereby reducing the charge-up on the surface of the resist material on the surface of the magnetic disk substrate 20 to be processed and arcing from dielectric breakdown. It is thought that it is not generated.

  However, when B / A increases extremely (in this embodiment, B / A is 8 or more), the generated secondary electrons 42 become excessive, and there are more electrons that exchange charges with the irradiated ions 14. Thus, it is considered that there is a high possibility that arcing is induced by creating a potential gradient (sheath) in the equipotential space 38.

  By the way, if B / A increases, the total area to be irradiated increases, and the injection amount per unit time decreases in proportion to the total area of (A + B). It should be noted that the problem can be solved by increasing the output current of the voltage pulse power supply 24. Considering the above results, B / A is preferably 1-6.

In order to perform the process of FIG. 1 of Example 1, an electrode having three grids as shown in FIG. 18 was examined under the same conditions as in Example 1. Here, the distance between the (first) grid 30, the second grid 130, and the third grid 131 is 15 mm, and the distance between the third grid 131 and the magnetic disk substrate 20 to be processed is 50 mm. However, the same grid is used for all the grids, and the arrangement of the through holes 33 is the same. When an experiment was performed using this electrode structure, the amount of implantation with respect to the ion irradiation time did not change much compared to the case of the single grid in FIG. 2, but the number of foreign matters adhering to the magnetic disk substrate 20 to be processed was small. It was confirmed to be about 1/10. The foreign matter is considered to be caused by arcing particularly generated on the surface of the grid 30 (first). Therefore, the reduction in the number of foreign matters is caused by the scattering path until the foreign matter generated by arcing reaches the magnetic disk substrate 20 to be processed. This can be understood as being blocked by the second grid 130 and the third grid 131.
[Comparative Example 1]

  A discrete track medium 18 was produced in the same manner as in Example 1 using an electrode structure as shown in FIG. 19 to which the present invention was not applied. Specifically, in order to perform the process of FIG. 1, in the ion irradiation apparatus shown in FIG. 2, the holding portion of the magnetic disk substrate 20 to be processed was tested using an electrode structure as shown in FIG. 19 to which the present invention is not applied. The process conditions were the same as in Example 1 except for the electrode structure.

  As a result, cracks that can be found at the optical microscope level as shown in FIG. 20 occurred on the entire surface of the magnetic disk substrate 20 to be processed. Due to this crack, both the metal film and the resist film constituting the treated magnetic disk substrate 20 were destroyed, and ion irradiation without damaging the substrate could not be performed.

  The present invention provides a discrete track medium in which separation processing is performed between disk tracks, and a bit pattern medium in which separation processing is also performed in the recording bit direction, and a manufacturing method thereof. It can be used.

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Adhesion layer, 3 ... First soft magnetic layer, 4 ... Antiferromagnetic coupling layer, 5 ... Second soft magnetic layer, 6 ... Underlayer, 7 ... First orientation control layer, 8 ... Second Orientation control layer, 9 ... first magnetic layer, 10 ... second magnetic layer, 11 ... resist film, 12 ... resist residue, 13 ... track guide separation region (non-magnetization region), 14 ... ion, 15 ... track separation region , 16 ... Protective film, 17 ... Lubricating film, 18 ... Discrete track medium, 20 ... Magnetic disk substrate to be processed, 21 ... Arc discharge unit, 22 ... Cathode, 23 ... Anode, 24 ... High voltage pulse power supply, 25 ... Arc discharge , 26 ... electrons, 27 ... magnetic duct, 28 ... processing chamber, 29 ... scanning magnet, 30 ... grid, 31 ... plasma beam, 32 ... pulse voltage, 33 ... through hole, 34 ... distance between grid and substrate, 35 ... potential distribution, 36 ... plasma plasma 37, pulse voltage, 38 ... equipotential space, 39 ... arcing, 40 ... plasma flow direction, 41 ... sheath, 42 ... secondary electrons, 44 ... electrode plate, 45 ... insulator cap, 46 ... cap support member, 47 ... Substrate holder, 48 ... Substrate holding member, 70 ... Vacuum chamber, 71 ... Parallel plate electrode, 72 ... Radio frequency (RF) power source, 73 ... Mass flow meter, 74 ... Glow discharge, 75 ... Blocking capacitor, 120 ... By resist Protected magnetic layer, 121 ... non-magnetized region implanted with ions, 122 ... physically damaged portion of non-magnetized region, 130 ... second grid, 131 ... third grid, 150 ... damaged portion of substrate due to arcing ( crack).

Claims (20)

A step of forming at least a magnetic film on at least one surface of the substrate, a step of forming a resist film having a concavo-convex pattern on the magnetic film to form a substrate to be processed, and irradiating ions from the direction of the resist film, A step of demagnetizing or softening a portion of the magnetic film corresponding to the concave portion of the resist film,
The ions are supplied to an equipotential space formed between an electrode plate on which the substrate to be processed having the same potential is disposed and a grid disposed to face the electrode plate and the substrate to be processed. A method of manufacturing a magnetic recording medium.   2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the ions supplied to the equipotential space are directly supplied from plasma formed on the upstream side of the grid.   The area of the electrode plate excluding the portion covered by the substrate to be processed is at least the area of the substrate to be processed disposed on the electrode plate exposed to the ions irradiated through the grid. The method of manufacturing a magnetic recording medium according to claim 1, wherein the magnetic recording medium is equal in size or greater.   4. The method of manufacturing a magnetic recording medium according to claim 3, wherein an area of the electrode plate excluding a portion covered with the substrate to be processed is 1 to 6 times an area of the substrate to be processed.   The method of manufacturing a magnetic recording medium according to claim 1, wherein the grid is composed of a plurality of sheets.   The step of demagnetizing or softening the magnetic film is performed by applying a pulse voltage that changes between a negative voltage and a ground or between a positive voltage and a ground to both the substrate to be processed and the grid according to the type of the ions. 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the method is performed in an applied state.   2. The method of manufacturing a magnetic recording medium according to claim 1, wherein when a metal atom is used as the ion species, the metal atom is selected from Cr, Mn, or V. _2. The magnetic recording medium according to claim 1, wherein when the ion species is generated as a gas, the gas used includes at least one kind of atoms or molecules of Ar, N ₂ , Ne, O _2, or F. Manufacturing method.   The method of manufacturing a magnetic recording medium according to claim 1, wherein the substrate is made of glass or silicon.   The magnetic recording medium manufacturing method according to claim 1, wherein the magnetic film forming step includes a step of forming a laminated film of a base film and a soft magnetic film on the substrate prior to the formation of the magnetic film. Method.   After the step of demagnetizing or softening the magnetic film, further removing the resist film, forming a protective film on the magnetic film, and forming a lubricating film on the protective film The method of manufacturing a magnetic recording medium according to claim 1, further comprising:   A plasma generation source for generating plasma by arc discharge, a processing chamber, and a plasma transport part for guiding the plasma of the plasma generation source into the processing chamber, and at least a magnetic film on both sides of the substrate, An apparatus for manufacturing a magnetic recording medium, in which a substrate to be processed having a resist film having a concavo-convex pattern formed thereon is installed in the processing chamber, and both surfaces of the substrate to be processed are irradiated with ions in the plasma. A substrate holder for holding the substrate to be processed is disposed in the processing chamber at a position facing the plasma transport unit, and the substrate holder has the same potential as the substrate holder between the plasma transport unit and the substrate holder. A magnetic recording medium characterized in that a grid is disposed and a pulse voltage generator for applying a pulse voltage to the grid is connected to the substrate holder. Forming apparatus.   The area of the substrate holder that is irradiated with the ions through the grid is equal to or greater than the area of the substrate to be processed that is also irradiated with the ions. Manufacturing apparatus for magnetic recording media.   14. The apparatus for manufacturing a magnetic recording medium according to claim 13, wherein an area of the substrate holder irradiated with the ions is 1 to 6 times an area of the substrate to be processed.   13. The apparatus for manufacturing a magnetic recording medium according to claim 12, wherein the grid is composed of a plurality of sheets.   A vacuum chamber; a gas introduction portion for introducing gas into the vacuum chamber; plasma is generated by glow discharge in the vacuum chamber; and at least a magnetic film on both surfaces of the substrate disposed in the vacuum chamber; An apparatus for manufacturing a magnetic recording medium for performing treatment by irradiating ions in the plasma on both surfaces of a substrate to be processed on which a resist film having a concavo-convex pattern is formed on the film, wherein the plasma is contained in the plasma chamber A substrate holder for holding the substrate to be processed is disposed at a position facing the substrate, and a grid having the same potential as the substrate holder is disposed between the plasma and the substrate holder, and the substrate holder and the grid An apparatus for manufacturing a magnetic recording medium, wherein a pulse voltage generator for applying a pulse voltage is connected.   After the glow discharge is generated in pulses by the high frequency power applied to the substrate to be processed and the grid, a pulse voltage is applied to the substrate to be processed and the grid before the ions in the glow discharge disappear. 17. The apparatus for manufacturing a magnetic recording medium according to claim 16, further comprising:   The area of the substrate holder that is irradiated with the ions through the grid is equal to or larger than the area of the substrate to be processed that is also irradiated with the ions. Manufacturing apparatus for magnetic recording media.   19. The apparatus for manufacturing a magnetic recording medium according to claim 18, wherein an area of the substrate holder irradiated with the ions is 1 to 6 times an area of the substrate to be processed.   17. The apparatus for manufacturing a magnetic recording medium according to claim 16, wherein the grid is composed of a plurality of sheets.

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