JP2001297431A - Method for forming magnetization pattern of magnetic recording medium, device for forming magnetization pattern, magnetic recording medium and magnetic recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and forming device capable of efficiently forming a pattern having good accuracy with few dimensional error, and for forming a magnetization pattern without damaging either a medium or a mask and with few occurrence of deficiency, namely, to provide a magnetic recording medium capable of high-density recording and a magnetic recorder for a short time and at a low cost. SOLUTION: The magnetization pattern is formed according to a process in which a magnetic recording medium provided with at least one layer of magnetic thin film on a substrate is irradiated with a pulsed energy line through a mask means, and a process in which an external magnetic field is applied. The method is for forming the magnetization pattern of the magnetic recording medium for cooling the mask means, when irradiating the energy line, and further, the device for forming the magnetization pattern, the magnetic recording medium on which the magnetization pattern is formed, and the magnetic recorder using the medium are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a magnetic pattern of a magnetic recording medium such as a magnetic disk used in a magnetic recording apparatus, a magnetic pattern forming apparatus, a magnetic recording medium, and a magnetic recording apparatus.

[0002]

2. Description of the Related Art A magnetic recording device represented by a magnetic disk device is widely used as an external storage device of an information processing device such as a computer, and has recently been used as a recording device for a moving image or a recording device for a set-top box. Is being done. A magnetic disk device generally includes a shaft for fixing one or more magnetic disks in a skewered manner, a motor for rotating a magnetic disk joined to the shaft via bearings, and a magnetic disk used for recording and / or reproduction. A head, an arm to which the head is attached, and an actuator capable of moving the head to an arbitrary position on the magnetic recording medium via the head arm. It is moving at a flying height.

A magnetic recording medium mounted on a magnetic disk device generally has a NiP layer formed on the surface of a substrate made of an aluminum alloy or the like, performs a required smoothing process, texturing process, and the like, and then forms a NiP layer on the NiP layer. It is manufactured by sequentially forming a nonmagnetic metal underlayer, a magnetic layer, a protective layer, a lubricating layer, and the like. Alternatively, it is manufactured by sequentially forming a nonmagnetic metal base layer, a magnetic layer (information recording layer), a protective layer, a lubricating layer, and the like on the surface of a nonmagnetic substrate made of glass or the like. Magnetic recording media include in-plane magnetic recording media and perpendicular magnetic recording media.

In the longitudinal magnetic recording medium, longitudinal recording is usually performed. The density of magnetic recording media has been increasing year by year, and in recent years, the density has been increasing at an annual rate of 60% or more. There are various techniques for realizing this high density, such as reducing the flying height of the magnetic head, employing a GMR head as the magnetic head,
Also, improvement of the magnetic material used for the recording layer of the magnetic disk,
Attempts have been made to reduce the distance between information recording tracks on a magnetic disk.

When the interval between information recording tracks is reduced to increase the number of tracks, a signal used for controlling the position of a data writing / reproducing head (hereinafter, may be referred to as a "servo signal") is adjusted accordingly. It must be denser, ie more, in the radial direction to allow precise control.

[0006]

Several methods have been proposed for servo signals. A widely used method is to make a hole near the head actuator of a drive (magnetic recording device), insert a pin with an encoder into the hole, engage the actuator with the pin, and move the head to the correct position. To write a servo signal.

As another method, the head is mechanically positioned at the outermost or innermost circumference, a first servo signal (or a reference signal for writing a servo signal) is written, and a next servo signal (or a servo signal) is written. Is a reference signal for writing a servo signal (or a reference signal for writing a servo signal).
Such as writing to a position where the output decreases by a certain percentage,
A method of writing a servo signal by the drive itself has also been proposed.

A master disk having an uneven surface corresponding to a servo signal is brought into close contact with a magnetic recording medium, and a magnetic field is further applied to magnetically transfer the unevenness of the master disk to the magnetic recording medium. A writing technique has also been proposed (JP-A-10-269566). Alternatively, a technique has been proposed in which a magnetic recording medium is locally irradiated with a laser beam to locally deform the medium to form physical unevenness, thereby forming an unevenness servo signal.

The recording density of a magnetic recording medium is several tens Gbit.
/ Inch ² years later, 100Gbit / inc
and try to reach h ² or more. 100Gbit / in
To achieve ch ^2, the track density 100ktpi
However, the conventional method has a problem that it is difficult to efficiently and accurately form a magnetization pattern.

For example, taking the writing of servo signals as an example, in the method using the above-mentioned external pins, since the center of gravity of the positioning mechanism and the center of gravity of the actuator are located at different positions, the track position cannot be controlled with high accuracy, and It was difficult to record the signal accurately. In the method of writing a servo signal by the drive itself, although there is no problem due to the shift of the center of gravity, the servo signal (or a reference signal for writing the servo signal) written before is used for the next writing. Are sequentially accumulated, errors accumulate.

In the method of statically writing servo signals by magnetic transfer, there are no problems of accumulated error and center of gravity, but it is very difficult to completely adhere the master disk to the magnetic recording medium to be magnetically transferred. In addition, dust may be trapped during transfer and the traces of the dust may be transferred to the magnetic recording medium, causing not only the medium to be defective, but also damaging the expensive master disk. The difficult problem I said remains.

Further, when this method is applied to a magnetic recording medium composed of a hard substrate made of glass, the adhesion becomes insufficient due to pinching of fine dust or the like, so that magnetic transfer cannot be performed or magnetic recording cannot be performed. It is very difficult to apply this method to a magnetic recording medium using a glass substrate, since cracks occur in the medium. Therefore, the present inventors have made Japanese Patent Application Nos. 2000-25854 and 2000-4
No. 8721 proposes a method of forming a magnetization pattern by irradiating energy rays through a mask means and applying an external magnetic field. According to this, a pattern can be efficiently and accurately formed, and the occurrence of defects is small without damaging the medium or the mask. However, in the present method, when a general magnet having a uniform magnetic field strength is used as the external magnetic field applying means, there is a possibility that the magnetization pattern of the magnetic recording medium may not be formed uniformly.

In this case, since the energy rays are also absorbed by the mask means, the temperature of the mask means rises, causing thermal expansion and realizing a very high density magnetization pattern.
There is a problem that an error is increased with respect to a desired dimension. Further, depending on the configuration of the magnetic pattern forming apparatus, the energy ray may be absorbed also in the portion for holding the magnetic recording medium, and the holding means also undergoes thermal expansion, causing eccentricity of the formed magnetic pattern and reducing dimensional errors. There was a risk of waking up.

The present invention solves these problems and provides a method and apparatus for forming a magnetic pattern which can efficiently form a high-precision pattern with a small dimensional error, and which does not damage a medium or a mask and has few defects. It is another object of the present invention to provide a magnetic recording medium and a magnetic recording device capable of high-density recording in a short time and at low cost.

[0015]

SUMMARY OF THE INVENTION The gist of the present invention is to irradiate a magnetic recording medium having at least one layer of a magnetic thin film on a substrate with a pulsed energy beam through a mask means, A method of forming a magnetic pattern by a step of applying a magnetic field, the method comprising forming a magnetic pattern on a magnetic recording medium, wherein the mask means is cooled when irradiating with energy rays. That is, a desired magnetization pattern can be formed with a small dimensional error and with high accuracy.

The gist of the present invention is to irradiate a magnetic recording medium having at least one magnetic thin film on a substrate with a pulsed energy beam through a mask means and to apply an external magnetic field. Forming a magnetization pattern by using a magnetic recording medium, wherein the medium holding means is cooled when the magnetic recording medium is held by the medium holding means and irradiated with energy rays. Exists. That is, thereby, eccentricity is suppressed, and a desired magnetization pattern can be formed with a small dimensional error and with high accuracy.

[0017] Preferably, cooling both the mask means and the medium holding means increases the accuracy. Preferably, if the whole or a part of the magnetic thin film of the magnetic recording medium is uniformly magnetized in advance in a desired direction by an external magnetic field, the resolution of the magnetization pattern can be increased. More preferably, when an external magnetic field is applied simultaneously with the irradiation of the energy ray, the resolution can be improved. When the external magnetic field to be applied in advance and the external magnetic field to be applied simultaneously with the irradiation of the energy beam are used in opposite directions, magnetic domains opposite to each other are clearly formed, which is a more preferable form. In addition, it is also possible to demagnetize by locally heating with an energy ray to form a magnetization pattern. It is preferable to irradiate the energy ray in a pulse shape because heat is hardly accumulated.

The wavelength of the energy ray is preferably 1100 nm or less. If the wavelength is shorter than this, the diffraction effect is small and the resolution is increased, so that a fine magnetization pattern is easily formed. The pulse width of the energy beam is desirably 1 μsec or less. If the pulse width is wider than this, heat generated by the energy given to the magnetic recording medium by the pulsed energy beam is dispersed, and the resolution tends to be reduced. The power per pulse of the pulse energy beam is 1000m
J / cm ² or less is preferable. If a power higher than this is applied, the surface of the magnetic recording medium may be damaged and deformed by the pulsed energy rays.

As the mask means, a photomask having a transparent portion and a non-transmissive portion according to a pattern, a porogram mask, or the like can be used. The energy beam is preferably a laser beam from the viewpoint of easy design of the optical system. It is preferable that the substrate of the magnetic recording medium is made of glass because the amount of heat provided by the energy rays is dispersed by thermal diffusion and energy can be used efficiently. In addition, there is an effect that the resolution of the magnetization pattern is increased due to the small heat diffusion.

When forming a magnetized pattern, the energy beam is partially applied to a region between the light source of the energy beam and the mask unit or between the mask unit and the medium and where the irradiation of the energy beam is not desired. It is preferable to provide a light-shielding plate capable of light-shielding, because it is possible to prevent energy rays from being applied repeatedly. As described above, this method is difficult to write as the density is increased, and is a main cause of an increase in the cost of the magnetic recording medium. The servo pattern for tracking the write / read head on the data track,
It is more effective when used for forming a reference pattern used for writing a servo pattern.

In the longitudinal magnetic recording medium, the track width has been narrowed due to the recent increase in density, and the influence of magnetic bleeding due to writing by a head has been relatively increasing. In particular, if the magnetic bleeding is large in a positioning signal such as a servo signal, the accuracy of the head position cannot be maintained, and the error rate may increase. According to the writing method of the present invention, since writing is selectively performed only on a spot where the temperature is rapidly increased in a spot manner, magnetic bleeding hardly occurs, and higher density recording can be performed.

Another aspect of the present invention is a step of irradiating a magnetic recording medium having at least one layer of a magnetic thin film on a substrate with a pulsed energy beam through a mask means and applying an external magnetic field. An apparatus for forming a magnetic pattern by a process, comprising: a mask unit, an external magnetic field applying unit, and a cooling unit for the mask unit. That is, a desired magnetization pattern can be formed with a small dimensional error and with high accuracy.

Alternatively, a magnetization pattern is formed by a step of irradiating a pulse-like energy beam through a mask means and a step of applying an external magnetic field to a magnetic recording medium having at least one magnetic thin film provided on a substrate. An apparatus for forming, a medium holding means for holding a magnetic recording medium,
An apparatus for forming a magnetic pattern of a magnetic recording medium, comprising: a mask unit; an external magnetic field applying unit; and a cooling unit for cooling the medium holding unit. That is, thereby, eccentricity is suppressed, and a desired magnetization pattern can be formed with a small dimensional error and with high accuracy.

[0024] Preferably, if both cooling means for the mask means and the medium holding means are provided, the accuracy is further improved. Another important aspect of the present invention is a magnetic recording medium characterized in that a magnetic pattern is formed by the above-described method of forming a magnetic pattern. Especially when the magnetic recording medium is a perpendicular magnetic recording medium, since it is used for high-density recording, not only is it difficult to write a servo signal, but also servo writing is a major cause of cost increase and application of a magnetic field is easy. ,
The effect is great when the present invention is applied.

Another important aspect of the present invention is a magnetic recording apparatus, which includes a magnetic recording medium, a driving unit for driving the magnetic recording medium in a recording direction, a magnetic head including a recording unit and a reproducing unit, and a magnetic recording medium. A magnetic recording apparatus comprising: means for moving a head relative to a magnetic recording medium; and recording / reproducing signal processing means for inputting a recording signal to the magnetic head and outputting a reproducing signal from the magnetic head. Is the magnetic recording medium according to any of the above.

Preferably, it is preferable that the magnetization pattern is reproduced by a magnetization head to obtain a signal, and a servo burst signal is recorded by the magnetic head based on the signal, since a signal with higher tracking accuracy can be written.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. When forming a magnetization pattern by a step of irradiating a pulsed energy beam through a mask means and a step of applying an external magnetic field to a magnetic recording medium having at least one magnetic thin film provided on a substrate, a mask is used. When the medium is irradiated with energy rays through the means, the energy rays are also absorbed by the mask means, so that the temperature of the mask means rises and causes thermal expansion, resulting in a large error in desired dimensions. This makes it difficult to form a magnetic pattern with high density and high accuracy.

Therefore, in the present invention, when irradiating the medium with an energy ray through the mask means, the mask means is cooled to prevent thermal expansion, so that a desired magnetization pattern can be formed with a small dimensional error and with high accuracy. The mask means may be any as long as it forms the density of the energy beam on the surface of the magnetic disk corresponding to the magnetization pattern to be formed. For example, a photomask having a transmission portion that transmits an energy ray according to a pattern, or a hologram mask on which a hologram that forms a specific pattern on a medium is recorded. Thereby, a plurality of or large-area magnetized patterns can be formed at a time, so that the magnetized pattern forming step is short and simple. A hologram mask is preferable because a sharp and clear pattern can be easily formed, but a photomask is preferable because it can be easily and inexpensively formed.

As a cooling means of the mask means, a method of applying an air flow to the mask (air cooling method), a method of circulating cooling water (water cooling method), a method of using other refrigerants, or the like, is used. Any material that can sufficiently remove generated heat may be used. For example, an air gun or the like may be arranged near the mask, and the air may be sent out such that the air hits the energy irradiation surface of the mask. Alternatively, a pipe may be provided around the mask so that cooling water circulates around the mask.

The mask may be cooled from the energy-irradiated surface of the mask, the back surface, or any of its side surfaces, and the cooling portion is not limited. However, the region directly irradiated with the energy beam and its vicinity (adjacent portion) are particularly heated. Because the rise is large, cooling is effective. Since the energy beam is irradiated in a pulsed manner, the irradiation period and the non-irradiation period are alternately repeated. However, cooling may be performed only during the irradiation period, only during the non-irradiation period, or through both periods as necessary. In the case of cooling during the irradiation period, a means that does not hinder the function of the mask to form the density of the energy beam is used. However, when cooling only during the non-irradiation period, this point need not be considered.

Alternatively, while monitoring the temperature of the mask with a temperature sensor or the like, the cooling condition may be controlled according to the temperature to keep the temperature constant. For example, in the case of water cooling, the cooling time, water temperature, and the like can be controlled, and in the case of air cooling, the cooling time, air volume, temperature, and the like can be controlled. The gas used for air cooling may be any gas that does not damage the mask,
For example, nitrogen, an inert gas such as Ar, air, or the like can be used, but air is preferred from the viewpoint of cost. More preferably, from the viewpoint of reducing errors during transfer, clean air, that is, air from which fine particles and dust in the air have been removed by a filter or the like is used.

In the case of water cooling, it is preferable to bring the temperature-controlled water into contact with the entire area or a part of the mask means via a water bag or a metal having good heat conductivity. In the case where water cooling or another refrigerant is used, it is preferable that the mask does not dew in order to transmit energy rays without impairing the function of the mask. For this reason, it is preferable to reduce the ambient humidity.

By keeping the temperature of the mask within a certain range by such a cooling means, the thermal expansion of the mask can be prevented and the magnetization pattern can be generated more precisely. The temperature of the mask is set to 0 ° C. or higher, and is preferably maintained at 30 ° C. or lower. However, when a pulsed energy beam having a high head value is irradiated, the temperature rises sharply at that moment, so that the temperature range may not always be maintained during the energy beam irradiation period.

This method is preferably carried out in an environment in which fine particles and dust, temperature and humidity are controlled, such as in a clean room. It is preferable that the environmental temperature be 0 ° C or higher and 30 ° C or lower. Alternatively, according to the present invention, when the magnetic recording medium is held by the medium holding unit and irradiated with the energy beam, the medium holding unit such as the spindle, the guide, and the pressing plate is also irradiated with the energy beam depending on the shape.
Energy rays are absorbed, the temperature rises, and thermal expansion occurs, resulting in a large error with respect to desired dimensions. For example, when the spindle, the holding plate, and the like thermally expand, the eccentricity of the medium increases. Therefore, it is difficult to form a high-density and high-precision magnetization pattern.

In the present invention, eccentricity is suppressed by cooling at least the medium holding means, and a desired magnetization pattern can be formed with a small dimensional error and with high accuracy. Preferably, removing heat generated by both the mask means and the medium holding means will increase the accuracy. The means for holding the magnetic recording medium refers to all mechanisms for holding the medium, and specifically includes a spindle, a guide, a holding plate, a spacer, a turntable, and the like. The region to be cooled may be all or a part of the holding means, and includes a region to be irradiated with energy rays or a region to be affected by the heat.

As the material used for the holding means, any material can be used as long as it can hold the magnetic recording medium in terms of strength and the like, but a material having thermally stable dimensions is preferred. Metal, alloy,
A resin, ceramic, glass, or the like can be used, but a metal or an alloy is preferable from the viewpoint that heat received by an energy ray can be diffused in a short time, and a metal or an alloy having high heat diffusion is particularly preferable.

The means for cooling the holding means and the cooling conditions are as follows:
This is the same as the means for cooling the mask described above. However,
The mask cooling unit and the medium holding unit cooling unit may have different cooling methods and conditions. It suffices if the part to which the energy beam is directly irradiated can be directly cooled, or the part in the vicinity thereof can be cooled via heat conduction. This method for forming a magnetic pattern
A servo pattern for tracking a write / read head on a data track, which has a relatively simple pattern and is more difficult to write as the density and accuracy are increased, and is a major cause of increased costs for magnetic recording media. Alternatively, the effect is great when used for forming a servo pattern writing reference pattern.

The magnetic recording medium on which the magnetization pattern is formed by the present method is inexpensive and enables high-density recording.
In the longitudinal magnetic recording medium, the track width has been narrowed due to the recent increase in density, and the influence of magnetic bleeding due to writing by a head has been relatively increasing. In particular, if the magnetic bleeding is large in a positioning signal such as a servo signal, the accuracy of the head position cannot be maintained, and the error rate may increase. According to the writing method of the present invention, since writing is selectively performed only on a spot where the temperature is rapidly increased in a spot manner, magnetic bleeding hardly occurs, and higher density recording can be performed.

Next, another configuration of the present invention will be described. In the present invention, the application of a magnetic field and local heating are combined, and at the time of heating, a mask means is arranged on the medium, and an energy beam or the like is irradiated therethrough, whereby a magnetization pattern can be generated in a short time and simply. it can. The mask means may be any as long as it forms the density of the energy beam on the surface of the magnetic disk corresponding to the magnetization pattern to be formed.
For example, a photomask having a transmission portion that transmits an energy ray according to a pattern, or a hologram mask on which a hologram that forms a specific pattern on a medium is recorded. Thereby, a plurality of or large-area magnetized patterns can be formed at a time, so that the magnetized pattern forming step is short and simple. A hologram mask is preferable because a sharp and clear pattern can be easily formed, but a photomask is preferable because it can be easily and inexpensively formed.

When an external magnetic field is applied simultaneously with heating,
By applying an external magnetic field over the heated large area, a plurality of magnetization patterns can be formed at once. Furthermore, once a mask is formed, a magnetized pattern of any shape can be formed on a medium, so that a complicated pattern or a special pattern that has been difficult to produce by a conventional method can be easily formed.

For example, in the phase servo method of a magnetic disk, a magnetization pattern extending linearly obliquely to the radius from the inner circumference to the outer circumference is used. Such a continuous pattern or a diagonal pattern in the radial direction is difficult to produce by a conventional servo pattern forming method of recording a servo signal one track at a time while rotating a disk, and requires a complicated calculation and configuration.

However, according to the present invention, once a mask corresponding to the shape is created, the pattern can be easily formed only by exposing the mask at a desired position on the disk. A mask in which a plurality of transmission portions are formed in accordance with the magnetization pattern to be formed is prepared, and the magnetic thin film is irradiated with a laser beam through the mask. If the beam diameter is set to a large diameter or an elongated elliptical shape and the like, and a magnetization pattern for a plurality of tracks or a plurality of sectors is collectively irradiated, the writing efficiency is further increased, and the servo writing time increases as the capacity increases. The problem is also improved and is very favorable.

This will be described in detail with reference to the drawings. First, a method of forming a magnetization pattern using a photomask will be described. FIG. 2 is a diagram illustrating an example of a method for forming a magnetization pattern using a photomask. The magnetic disk 101 is uniformly magnetized in advance in one circumferential direction by an external magnetic field. After that, the magnetic disk 101 is mounted on the spindle 120. That is, it is arranged on the turntable 121, the photomask 102 is attached via the spacer 122, the pressing plate 123 is further placed thereon, and is fixed by a not-shown fixing screw. That is, the magnetic disk 101 and the photomask 102
A space S is provided between. Here, pulsed laser light 103 is irradiated. At the same time, an external magnetic field 104 is applied. This external magnetic field is in the opposite direction to the external magnetic field when magnetized uniformly previously.

At this time, the air guns 130, 13
Blow clean air from 0 '
2 and the entire disk holding means are cooled. The photomask may be a mask provided with a transmission part and a non-transmission part corresponding to a desired magnetization pattern, and a metal such as Cr, a soft magnetic material such as NiFe is formed on a master such as quartz glass or soda lime glass. Is formed by sputtering, a photoresist is applied thereon, and desired transmissive portions and non-transmissive portions can be formed by etching or the like.

Next, a method of forming a magnetization pattern using a hologram mask will be described. FIG. 3 is an explanatory diagram of an example of a method for forming a magnetization pattern using a hologram mask. As shown in FIG. 3A, the object light 107 is passed through a photomask 106 having a transmission portion / non-transmission portion formed according to a magnetization pattern to be formed on a magnetic disk.
The upper photopolymer 105 is irradiated. Here, reference light 109 is irradiated through a prism, and a hologram due to interference between the object light 107 and the reference light 109 is formed on the photopolymer 10.
Record on 5

Note that a pattern to be exposed may be obtained by calculation without using a photomask, and a hologram mask may be created accordingly. When this is irradiated with reference light 109 through a prism as shown in FIG. 3B, a holographic pattern is formed at a predetermined distance from the photopolymer. Using this principle, as shown in FIG. 3C, a laser beam (reference light) 109 is irradiated from a laser light source 110 to a photopolymer 105 through a prism 108, and a magnetic disk 1 is formed on a surface on which a pattern corresponding to a holographic image is formed.
01, the reflector 111 is moved to scan the reference light 109 over the photopolymer 105, and at the same time, an external magnetic field 104 is applied to form a magnetization pattern.

At this time, at the same time, clean air is blown out from the air gun 130 "to cool the photomask 102. The magnetic recording medium and the mask means may be in close contact or may have a gap, but preferably a gap is provided. The spacing in the case of providing the gap is preferably 1 μm or more.Dust that easily adheres to the medium and cannot be easily removed by air blow or the like is usually used.
Most are less than 1 μm. The interval is 1μ.
If it is less than m, the undulation of the medium surface may cause an unexpected contact of the magnetic pattern forming portion with the mask means, which may damage the mask or the magnetic recording medium. More preferably, it is 5 μm or more.
The spacing is set to 1 mm or less. If it is larger than this, the diffraction of the energy ray is large and the magnetization pattern is apt to be blurred. However, when an imaging optical system is used, the distance may be 1 mm or more.

When a photomask is used, it is preferable to keep the distance from the medium as short as possible within the range of the above conditions. This is because the longer the distance, the more easily the magnetic pattern is blurred due to the wraparound of the irradiated energy beam. In order to improve this and obtain a clearer pattern, by forming a thin transmission part that functions as a diffraction grating outside the transmission part of the mask, or by providing a means that functions as a half-wave plate The wraparound light can be canceled by interference.

On the other hand, when a hologram mask is used,
Since the distance of the pattern corresponding to the holography to the image plane is determined in advance, the distance from the medium is adjusted to the distance. By using a prism as shown in FIG. 3, the mask and the medium can be brought close to each other. When forming a magnetized pattern, a light-shielding plate capable of partially shielding energy rays is provided between the light source of the energy rays and the mask means, or in an area where irradiation between the mask means and the medium is not desired. It is preferable to provide a structure for preventing re-irradiation of energy rays.

The light-shielding plate only needs to be one that does not transmit the wavelength of the energy beam to be used, and may reflect or absorb the energy beam. However, if the heat of the energy ray is absorbed, it is heated and easily affects the magnetization pattern.
Those having good thermal conductivity and high reflectivity are preferred. For example,
It is a metal plate of Cr, Al, Fe, or the like. It is preferable that the substrate of the magnetic recording medium of the present invention be made of glass because the amount of heat given by the energy rays dispersed by heat diffusion is small and energy can be used efficiently. In addition, there is an effect that the resolution of the magnetization pattern is increased due to the small heat diffusion. In the case of a glass substrate, it is preferable to provide a gap between the mask means and the substrate, since the substrate is resistant to entrapment of dust and the like and the hardness of the substrate surface does not cause cracks in the magnetic recording medium or damage to the master.

It is preferable to provide a protective layer having a thickness of 50 nm or less on the magnetic thin film in order to prevent the medium from being damaged by the magnetization pattern forming process. When there are a plurality of magnetic thin films, a protective layer may be provided on the magnetic thin film near the outermost surface. More preferably, a lubricating layer having a thickness of 10 nm or less is provided on the protective layer. As a method for maintaining the gap between the magnetic pattern forming region of the magnetic recording medium and the masking means, any method can be used as long as both can be maintained at a constant distance. For example, the mask and the medium may be held by a specific device to keep a certain distance. Further, a spacer may be inserted between the two at a place other than the magnetization pattern forming region. A spacer may be integrally formed with the mask itself.

Between the mask means and the magnetic recording medium,
Providing a spacer on the outer peripheral portion and / or inner peripheral portion of the magnetic pattern forming region of the medium has the effect of correcting the undulation on the surface of the magnetic recording medium, so that the accuracy of forming the magnetic pattern can be improved. Any means for locally heating the magnetic thin film may be used as long as it can partially heat the surface of the recording layer, but a laser is preferable because it can prevent irradiation of unnecessary portions with energy rays. Pulsed energy rays which are difficult to apply are preferred. Specifically, an excimer laser (248 nm), a Q switch laser (10
64 nm), a second harmonic (523 nm), and a third harmonic (355 n).
m) or fourth harmonic (266 nm), Ar laser (4
88 nm, 514 nm), ruby laser (694 n)
m).

It is preferable that the wavelength of the energy ray is 1100 nm or less. If the wavelength is shorter than this, the diffraction effect is small and the resolution is increased, so that a fine magnetization pattern is easily formed. More preferably, the wavelength is 600 nm or less. In addition to the high resolution, the small diffraction means that the gap between the mask means and the magnetic recording medium by the gap can be widened, handling is easy, and the magnetic transfer device can be easily configured. The wavelength is 150
It is preferably at least nm. If it is less than 150 nm, the absorption of the synthetic quartz used for the mask becomes large, and the heating tends to be insufficient. If the wavelength is 350 nm or more, optical glass can be used as a mask.

When the wavelength is 1100 nm or less, the energy ray absorptivity of the mask means is increased and the mask is easily heated, so that the effect of the present invention is great. Wavelength 600nm
The effect is higher when used below. The power per pulse of the pulsed energy beam is preferably 1000 mJ / cm ² or less. If a power higher than this is applied, the surface of the magnetic recording medium may be damaged and deformed by the pulsed energy rays. More preferably, it is 500 mJ / cm ² or less, and still more preferably, 100 mJ / cm ² or less. In this region, a magnetization pattern with high resolution is easily formed even when a substrate having relatively large thermal diffusion is used. The power is 10mJ /
cm ² or more. If it is smaller than this, the temperature of the magnetic thin film does not easily rise and magnetic transfer hardly occurs.

The pulse width of the pulse energy beam is 1 μm.
sec or less is desirable. If the pulse width is wider than this, the heat generated by the energy given to the magnetic recording medium by the pulsed energy beam is dispersed, and the resolution tends to decrease. If it is 1 μsec or less, the cooling effect of the cooling means of the present invention can be sufficiently exhibited. In addition, when the power per pulse is the same, the shorter the pulse width and the stronger the energy at once, the smaller the thermal diffusion and the higher the resolution of the magnetization pattern. More preferably 10
0 nsec or less. In this region, a magnetization pattern with high resolution is easily formed even when a substrate such as Al having a relatively large thermal diffusion of a metal is used. That is, if importance is placed on the resolution, the shorter the pulse width, the better. However, the pulse width is preferably at least 1 nsec. This is because it is preferable to maintain the heating until the magnetization reversal of the magnetic thin film is completed.

As one type of pulsed laser, there is a laser such as a mode-locked laser capable of generating a femtosecond level ultrashort pulse at a high frequency. During the period of irradiating the ultrashort pulse at a high frequency, the laser is not irradiated for a very short time between each ultrashort pulse, but the heating portion is hardly cooled because it is a very short time. That is, the region once heated to the Curie temperature or higher is maintained at the Curie temperature or higher.

Therefore, in such a case, the continuous irradiation period (the continuous irradiation period including the time during which the laser is not irradiated between the ultrashort pulses) is one pulse. In addition, the integral value of the irradiation energy amount during the continuous irradiation period is calculated as power per pulse (mJ /
cm ² ). Next, the principle of forming a magnetization pattern by local heating and application of a magnetic field will be described. In the present invention, the following aspects can be taken as a combination of the step of locally heating the magnetic thin film and the step of applying an external magnetic field to the magnetic thin film.

Embodiment 1: A method in which a magnetic thin film is uniformly magnetized in a desired direction by a strong external magnetic field before heating, and then a desired portion is heated and demagnetized to near the Curie point to form a magnetization pattern. According to this, the magnetization pattern can be formed most easily. In addition, since the magnetic thin film is uniformly magnetized, normal magnetic recording can be performed after forming a magnetization pattern by this method.

Mode 2: A magnetized pattern is formed by magnetizing a magnetic thin film uniformly in a desired direction with a strong external magnetic field before heating, and then heating a desired portion to near the Curie point and applying a weak magnetic field to demagnetize it. how to. According to this, since the demagnetization can be completely performed, a magnetization pattern having a large signal intensity can be obtained. Aspect 3: By applying a weak external magnetic field simultaneously with heating,
A method in which only the heating part is magnetized in the direction of the external magnetic field to form a magnetized pattern. According to this, the magnetization pattern can be formed most easily, and the external magnetic field may be weak.

Embodiment 4: Before heating, the magnetic thin film is uniformly magnetized in a desired direction with a strong external magnetic field, and then the desired portion is heated, and at the same time, a weak magnetic field is applied in the opposite direction to that before the heating to magnetize the magnetic pattern. How to form. According to this, a magnetization pattern having the highest signal intensity and good C / N and S / N can be obtained. Hereinafter, each embodiment will be described.

The direction of the external magnetic field in the first embodiment differs depending on the type of the magnetic thin film of the magnetic recording medium. In the case of a medium having an easy axis of magnetization in an in-plane direction, the magnetic thin film is applied so as to be magnetized in the same direction as or in the opposite direction to the traveling direction of the data writing / reproducing head (the relative movement direction of the medium and the head). . Further, when the magnetic recording medium has a disk shape, it is also possible to apply the magnetic recording medium so as to be magnetized in the radial direction. When the easy axis is perpendicular to the in-plane direction, the magnetic thin film
It is applied so as to be magnetized in any of the vertical directions.

The strength of the magnetic field depends on the characteristics of the magnetic thin film of the magnetic recording medium, and it is preferable that the magnetic thin film is magnetized by a magnetic field at least twice the coercive force at room temperature. If it is lower than this, the magnetization may be insufficient. However, the coercive force of the magnetic thin film at room temperature is preferably 5 times or less in view of the capability of the magnetizing device used for applying the magnetic field. In Embodiment 2, the direction and intensity of the external magnetic field before heating are exactly the same as in Embodiment 1.

The direction of the magnetic field applied simultaneously with the heating is set to a direction perpendicular to the in-plane direction when the medium has an easy axis in the in-plane direction, and to a direction perpendicular to the in-plane direction when the medium has the easy axis in the in-plane direction. Is the in-plane direction of the medium. Thus, the magnetic field is applied to erase the magnetization. The strength of the magnetic field depends on the characteristics of the magnetic thin film of the magnetic recording medium, but is smaller than the coercive force of the magnetic thin film at room temperature. Preferably, the magnetic field is at least 1/8 of the coercive force of the magnetic thin film at room temperature. If it is lower than this, the heating section may be magnetized again in the same direction as the surroundings under the influence of the magnetic field from the surrounding magnetic domains during cooling.

However, the coercive force of the magnetic thin film at room temperature was 2 /
It is preferable to make it three times or less. If it is larger than this, the magnetic domains around the heating section may be affected. More preferably, it is set to 1/2 times or less. As long as heating can be performed to a temperature at which the coercive force of the magnetic thin film is reduced,
For example, it is near the Curie temperature of the magnetic thin film. Preferably, it is heated to 100 ° C. or higher. Magnetic thin films that are affected by an external magnetic field below 100 ° C. tend to have low domain stability at room temperature. Further, the heating temperature is preferably 400 ° C. or lower. If it exceeds this, the magnetic thin film may be deformed.

The direction of the external magnetic field at the same time as the heating in the mode 3 is as follows.
It depends on the type of the magnetic thin film of the magnetic recording medium. In the case of a medium having an easy axis of magnetization in an in-plane direction, the magnetic thin film is applied so as to be magnetized in the same direction as or in the opposite direction to the traveling direction of the data writing / reproducing head (the relative movement direction of the medium and the head). . Further, when the magnetic recording medium has a disk shape, it is also possible to apply the magnetic recording medium so as to be magnetized in the radial direction. When the easy axis is perpendicular to the in-plane direction,
The application is performed so that the magnetic thin film is magnetized in any of the perpendicular directions.

The strength of the magnetic field is the same as the strength of the external magnetic field simultaneously with the heating in the second embodiment. The heating temperature is the same as in the second embodiment. In Embodiment 4, the direction and intensity of the external magnetic field before heating are exactly the same as those in Embodiment 1. The strength of the magnetic field applied simultaneously with the heating is the same as in the second embodiment, but the direction is applied in the opposite direction to the direction of the pre-heating magnetic field so that the magnetization is locally reversed. The heating temperature is the same as in the second embodiment.

In a field in which this method is particularly effective, the magnetization pattern is simple, but a servo signal or a reference signal for writing a servo signal, which has become more difficult to write with a head due to an increase in its recording density. Is the use of Writing of servo signal or reference signal for writing servo signal
Since writing is performed at a half pitch of the data track pitch, it is difficult to ensure the writing accuracy.
By applying this method, a servo signal for high density or a reference signal for writing a servo signal can be easily written.

Next, the configuration of the magnetic recording medium of the present invention will be described. As the substrate in the magnetic recording medium of the present invention, for example, Al such as an Al-Mg alloy containing Al as a main component is used.
It is possible to use alloy substrates, Zn-Mg alloys, ordinary soda glass, aluminosilicate glass, amorphous glass, crystallized glass, silicon, titanium, ceramics, various types of resin, or a combination of these. it can. Among them, the use of a glass substrate such as crystallized glass is preferable because the advantage that the mask means and the magnetic recording medium are not in contact is particularly utilized.

In the process of manufacturing a magnetic disk, it is usual to wash and dry the substrate first. In the present invention as well, from the viewpoint of ensuring the adhesion of each layer, it is necessary to wash and dry the substrate before its formation. Is desirable. In manufacturing the magnetic recording medium of the present invention, a nonmagnetic metal coating layer such as NiP may be formed on the surface of the nonmagnetic substrate.

When the nonmagnetic metal coating layer is formed, a method used for forming a thin film such as an electroless plating method, a sputtering method, a vacuum deposition method, or a CVD method can be used. In the case of a substrate made of a conductive material, it is possible to use electrolytic plating. The thickness of the nonmagnetic metal coating layer may be 50 nm or more. However, considering the productivity of the magnetic disk medium, etc., 50 n
It is preferably from m to 500 nm. More preferably, it is 50 nm or more and 300 nm or less.

The area where the non-magnetic metal coating layer is formed is desirably the entire area of the substrate surface, but the present invention can be applied to only a part of the area, for example, only the area to be textured. Alternatively, concentric texturing may be applied to the surface of the substrate or the surface of the substrate on which the nonmagnetic metal coating layer is formed. In the present invention, concentric texturing is, for example, mechanical texturing using loose abrasive grains and texture tape or texturing using a laser beam, or by using these together, by polishing in the circumferential direction. This refers to a state in which a large number of microgrooves are formed in the circumferential direction of the substrate.

The type of free abrasive grains for mechanical texturing is most preferably diamond abrasive grains, especially those whose surfaces are graphitized. Alumina abrasive grains are widely used as abrasive grains for mechanical texturing, but diamond abrasive grains are particularly considered from the viewpoint of the in-plane orientation medium that orients the axis of easy magnetization along the texturing grooves. Has extremely good performance. Although the cause is not clear at present, extremely reproducible results have been obtained.

The surface of the substrate has basically no effect on the effect of the present invention no matter what value the surface roughness (Ra) takes, but the fact that the flying height of the head is as small as possible is necessary for realizing high density magnetic recording. Is effective, and one of the features of these substrates is excellent surface smoothness.
a is preferably 2 nm or less, more preferably 1 nm or less, and particularly preferably 0.5 nm or less. However, the determination of Ra here is based on the case where measurement is performed using a stylus type surface roughness meter. At this time, the tip of the measuring needle has a radius of about 0.2 μm.

Next, an underlayer or the like may be formed between the substrate and the magnetic thin film layer. The underlayer is intended to refine the crystal and control the orientation of the crystal plane,
Those containing Cr as a main component are often used. As a material of the underlayer containing Cr as a main component, in addition to pure Cr, Cr, V, Ti, Mo, or Cr is used for the purpose of crystal matching with the recording layer.
Also includes those to which second and third elements such as Zr, Hf, Ta, W, Ge, Nb, Si, Cu, and B are added, and Cr oxide. Above all, pure Cr, Ti, Mo, W, V, Ta, S
Those having i, Nb, Zr and Hf are preferred. The content of the second and third elements varies depending on the respective elements, but is generally 1 atomic% to 50 atomic%, preferably 5 atomic% to 30 atomic%, more preferably 5 atomic% to 20 atomic%. Atomic% range.

The thickness of the underlayer may be sufficient if it can express this anisotropy, and is 0.1 to 50 nm.
Preferably 0.3 to 30 nm, more preferably 0.5
〜１０10 nm. The substrate may or may not be heated during the formation of the underlayer mainly composed of Cr. A soft magnetic layer may be provided on the underlayer in some cases. In particular, the effect is large and is often used for a keeper medium or a perpendicular recording medium having little magnetization transition noise.

The soft magnetic layer is not particularly limited as long as it has a relatively high magnetic permeability and a small loss, and is arbitrary. Typical examples thereof include NiFe and a material to which Mo or the like is added as a third element. Often used. The optimum magnetic permeability varies greatly depending on the characteristics of the head used for writing data and the characteristics of the recording layer, but generally, the maximum magnetic permeability is 10 to 1000.
It is preferably about 000 (H / m).

Next, a recording layer is formed. A layer of the same material as the underlayer or another non-magnetic material may be inserted between the recording layer and the soft magnetic layer. When forming the recording layer, the substrate may or may not be heated. As the recording layer,
A Co alloy magnetic film, a rare earth magnetic film represented by TbFeCo, a transition metal / noble metal laminated film represented by a laminated film of Co and Pd, and the like are used. The Co alloy magnetic layer is usually made of pure Co, CoNi, CoSm, CoCrT.
a, a Co alloy magnetic material generally used as a magnetic material such as CoNiCr and CoCrPt is used. An element such as Ni, Cr, Pt, Ta, W, or B or a compound such as SiO ₂ may be added to these Co alloys. For example, CoCrPtTa, CoCrPtB, CoNiPt,
CoNiCrPtB and the like. The thickness of the Co alloy magnetic layer is arbitrary, but is usually 5 to 50 nm, preferably 1 to 50 nm.
0 to 30 nm. The recording layer may be formed by laminating two or more layers via an appropriate non-magnetic intermediate layer or directly. At that time, the composition of the magnetic materials to be laminated may be the same or different.

The rare earth magnetic layer is usually made of TbFeC
o, rare earth magnetic materials generally used as magnetic materials such as GdFeCo, DyFeCo, and TbFe are used.
Tb, Dy, Ho, etc. are added to these rare earth alloys,
Ti or A for the purpose of preventing oxidation deterioration
1, Pt may be added. The thickness of the rare earth magnetic layer is arbitrary, but is usually about 5 to 100 nm.
The recording layer may be formed by laminating two or more layers via an appropriate non-magnetic intermediate layer or directly. At that time, the composition of the magnetic materials to be laminated may be the same or different. In particular, the rare earth magnetic layer is suitable for high recording density recording because the rare earth magnetic layer has an amorphous structure film and magnetization in a direction perpendicular to the media plane, and the recording of the present invention can be more easily applied.

Similarly, as a laminated film of a transition metal and a noble metal based material suitable for perpendicular magnetic recording, Co / Pd, Co / P
A laminated film material generally used as a magnetic material such as t, Fe / Pt, Fe / Au, and Fe / Ag is used. The transition metal and the noble metal of these laminated films need not be particularly pure, and may be an alloy mainly containing them. The thickness of the laminated film is arbitrary, but is usually about 5 to 1000 nm. The method of lamination is also arbitrary, and it is not always necessary to laminate two materials.

In the present invention, it is preferable to form a protective layer on the magnetic thin film. That is, the outermost surface of the medium is covered with the hard protective layer. The protective layer functions to prevent damage to the magnetic thin film due to collision with a head or a mask during formation of a magnetization pattern or pinching between the mask and dust or dirt. This is particularly important when the magnetization pattern forming process is performed in the normal atmosphere. When there are a plurality of magnetic thin films, a protective layer may be provided on the magnetic thin film near the outermost surface. The protective layer may be provided directly on the magnetic thin film, or may have another layer interposed therebetween as required.

As the protective layer, a carbonaceous layer such as carbon, hydrogenated carbon, nitrogenated carbon, amorphous carbon, or SiC, or a hard material such as SiO ₂ , Zr ₂ O ₃ , SiN, or TiN can be used. It may be transparent or opaque. Part of the energy beam is also absorbed by the protective layer, and acts to locally heat the magnetic thin film by heat conduction. For this reason, if the protective layer is too thick, the magnetization pattern may be blurred due to lateral heat conduction,
The thinner the film, the better. Further, it is preferable that the thickness be thin in order to reduce the distance between the magnetic thin film and the head during recording and reproduction. Therefore, the thickness is preferably 50 nm or less, particularly preferably 30 nm or less. However, in order to obtain sufficient durability, 1n
m or more is preferable.

Further, the protective layer may be composed of two or more layers. It is preferable to provide a protective layer immediately above the magnetic layer with a layer containing Cr as a main component, since the effect of preventing oxygen from permeating the magnetic layer is high. More preferably, a lubricating layer is formed on the protective layer. Examples of the lubricant used for the lubricating layer include a fluorine-based lubricant, a hydrocarbon-based lubricant and a mixture thereof. The lubricating layer is preferably thinner so as not to hinder the formation of the magnetic pattern. It is preferably 10 nm or less. In order to obtain sufficient lubrication performance, the thickness is preferably 1 nm or more.

The formation of the magnetization pattern on the magnetic recording medium is performed on the recording layer, and is usually performed by any of the conventional methods after forming the protective layer or the protective film and the lubricating layer. If there is no concern about oxidation of the recording layer, the treatment may be performed immediately after the formation of the recording layer. The method for forming each layer of the magnetic recording medium is arbitrary, and examples thereof include physical vapor deposition methods such as direct current (magnetron) sputtering, high frequency (magnetron) sputtering, ECR sputtering, and vacuum deposition.

The conditions for the film formation are not particularly limited, and the ultimate vacuum degree, the method of heating the substrate and the substrate temperature, the sputtering gas pressure, the bias voltage and the like may be appropriately determined by the film forming apparatus. For example, in the case of sputtering film formation, the ultimate degree of vacuum is usually 5 × 10 ⁻⁶ Torr or less, the substrate temperature is from room temperature to 400 ° C., and the sputtering gas pressure is 1 × 1.
0 ^{−3 to} 20 × 10 ⁻³ Torr, and the bias voltage is generally 0 to −500V.

In forming the film, the nonmagnetic substrate may be heated before the underlayer is formed, or when a transparent substrate having a low heat absorption is used, the heat absorption may be increased. A substrate may be heated after forming a seed layer containing Cr as a main component or an underlayer having a B2 crystal structure, and then a recording layer or the like may be formed. When the recording layer is a rare earth magnetic film, from the viewpoint of corrosion and oxidation prevention, the innermost and outermost portions of the disk are first masked, and the recording layer is formed.
A method of removing the mask at the time of the subsequent formation of the protective layer and completely covering the recording layer with the protective film, or, in the case of two protective layers, forming a film while masking the recording layer and the first protective layer. It is preferable to remove the mask when forming the second protective layer and completely cover the recording layer with the second protective film because corrosion and oxidation of the rare earth magnetic layer can be prevented.

The magnetic recording apparatus of the present invention comprises at least the magnetic recording medium described above, a driving unit for driving the magnetic recording medium in the recording direction, a magnetic head including a recording unit and a reproducing unit, and And a recording / reproducing signal processing means for inputting a signal to the magnetic head and reproducing an output signal from the magnetic head.

A magnetic disk device, which is a typical magnetic recording device, will be described as an example. A magnetic disk device generally includes a shaft for fixing one or more magnetic disks in a skewered manner, a motor for rotating a magnetic disk joined to the shaft via bearings, and a magnetic disk used for recording and / or reproduction. A head, an arm to which the head is attached, and an actuator capable of moving the head to an arbitrary position on the magnetic recording medium via the head arm. It is moving at a flying height. The recording information is converted into a recording signal via a signal processing means and recorded by a magnetic head. Further, the reproduction signal read by the magnetic head is inversely converted through the signal processing means to obtain reproduction information.

On the disk, information signals are recorded in sector units along concentric tracks. Servo patterns are usually recorded between sectors. The magnetic head reads a servo signal from the pattern, thereby accurately performing tracking at the center of the track, and reads an information signal of the sector. Tracking is also performed during recording.

As described above, a servo pattern for generating a servo signal is required to have a particularly high precision due to the property of being used for tracking when recording information. In addition, since the servo pattern which is often used at present is composed of two sets of patterns which are shifted from each other by ピ ッ チ pitch, it is necessary to form the servo pattern at every ピ ッ チ pitch of the information signal, and the accuracy is twice as high. Is required.

However, in the conventional servo pattern forming method, the write track width is 0.2 to 0.2 due to the influence of vibration caused by the difference between the center of gravity of the external pin and that of the actuator.
The limit is about 0.3 μm, and the accuracy of the servo pattern cannot keep up with the increase in the track density, which is preventing the improvement of the recording density and the cost reduction of the magnetic recording apparatus. According to the present invention, a highly accurate magnetization pattern can be formed efficiently and efficiently by using a mask exposure method, so that a servo pattern can be accurately formed in a much shorter time and a shorter time than a conventional servo pattern formation method. And the track density of the medium can be increased. Therefore, a magnetic recording device using this medium can perform high-density recording.

Further, if the phase servo method is used, a servo signal that changes continuously can be obtained, so that the track density can be further increased, and tracking with a width of 0.1 μm or less is possible, and higher density recording is possible. is there. As described above, in the phase servo method, for example, from the inner circumference to the outer circumference,
A magnetization pattern that extends linearly obliquely to the radius is used. Such a continuous pattern or an oblique pattern in the radial direction is difficult to produce by a conventional servo pattern forming method of recording a servo signal one track at a time while rotating a disk, and a complicated calculation and configuration are required.

However, according to the present invention, once a mask corresponding to the shape is once formed, the pattern can be easily formed only by exposing the mask at a desired position on the disk. It can be created easily, in a short time, at low cost. As a result, it is possible to provide a phase servo type magnetic recording device capable of high-density recording. In the conventional mainstream servo pattern forming method, a dedicated servo writer is used in a clean room after a medium is incorporated in a magnetic recording device (drive).

Each drive is mounted on a servo writer, and pins of the servo writer are inserted through holes in either the front or rear surface of the drive, and recording is performed one pattern at a time along a track while mechanically moving the magnetic head.
Therefore, it takes a very long time of about 15 to 20 minutes per drive. These operations had to be performed in a clean room because a dedicated servo writer was used and a hole was formed in the drive, which was complicated in the process and increased the cost.

According to the present invention, a servo pattern or a reference pattern for writing a servo pattern can be collectively recorded by irradiating an energy beam through a mask in which a pattern has been recorded in advance. Can be formed. A magnetic recording apparatus incorporating a medium on which a servo pattern is formed in this way eliminates the need for the servo pattern writing step.

Alternatively, in a magnetic recording apparatus incorporating a medium on which a servo pattern writing reference pattern is formed, a desired servo burst signal can be written in the apparatus based on the reference pattern. Is unnecessary, and there is no need to work in a clean room.
A magnetic recording device having a high-precision servo pattern can be obtained in a simple process at a low cost.

Further, it is not necessary to make a hole on the back side of the magnetic recording apparatus, which is preferable in terms of durability and safety. Further, by providing a gap between the mask and the medium, it is possible to prevent deformation and damage of the medium due to contact with the mask and damage to the medium due to pinching of fine dust or dust, thereby preventing generation of defects.

As described above, according to the present invention, a magnetic recording device capable of performing high-density recording with high reliability can be obtained in a simple process at low cost. Various magnetic heads such as a thin film head, an MR head, a GMR head, and a TMR head can be used. Set the reproducing part of the magnetic head to M
By using the R head, a sufficient signal intensity can be obtained even at a high recording density, and a magnetic storage device having a high recording density can be realized.

Further, the magnetic head was used with a flying height of 0.00.
When flying at a height lower than the conventional height of 1 μm or more and less than 0.05 μm, the output is improved and a high device S / N is obtained.
A large-capacity and highly reliable magnetic storage device can be provided. The recording density can be further improved by combining a signal processing circuit based on the maximum likelihood decoding method. For example, the track density is 10 kTPI or more, the linear recording density is 200 kFCI or more,
A sufficient S / N can be obtained even when recording / reproducing at a recording density of 2 Gbits / square inch or more.

Further, the reproducing portion of the magnetic head is disposed between a plurality of conductive magnetic layers which generate a large resistance change due to a relative change in their magnetization directions due to an external magnetic field, and the conductive magnetic layers. G consisting of a conductive non-magnetic layer
MR head or G using spin valve effect
By using an MR head, the signal strength can be further increased, and 3 gigabits or more per square inch can be achieved.
A highly reliable magnetic storage device having a linear recording density of 40 kFCI or more can be realized.

[0100]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The magnetic recording medium of the present invention will be described in detail below, but is not limited by the embodiments unless it goes beyond the scope of the gist. Example 1 A 2.5-inch-diameter aluminosilicate glass substrate was washed and dried, and a degree of vacuum reached on it was 1 × 10 ⁻⁷ Torr.
Substrate temperature: 350 ° C., bias voltage: -200 V, sputtering gas pressure: Ar 3 × 10 ⁻³ Torr, NiAl 600 °, Cr ₉₄ Mo ₆ 100 °, Co ₇₂ Cr ₁₈ Pt ₁₀ as a recording layer. At 220 °, sputtered carbon was deposited at 50 ° as a protective layer. As a lubricating layer, a 1.5-nm-thick fluorinated lubricant is applied thereon, baked at 100 ° C. for 40 minutes, and has a coercive force of 3000 at room temperature.
An Oe magnetic disk for in-plane magnetic recording was obtained.

In order to form a magnetization pattern, first, an electromagnet was configured so that the direction of a magnetic field was the same as the direction of rotation of the disk, and was applied at an intensity of about 10 kOe to uniformly magnetize the disk surface in the circumferential direction. . Then, as shown in FIG. 1, 15 mm in the radial direction (from a radius of 15 mm to a radius of 30 mm) and a width of 1 μm in the circumferential direction due to unevenness having a depth of about 20 nm.
Mask having a pattern in which the transmission pattern is repeated every 12 ° in the circumferential direction and extends radially in the radial direction (the projections are non-transmissive, the recesses are transmission portions, and the projection portions are more disc-shaped). The magnetic disk was allowed to stand still.

Then, the angle is set so that the position of the pattern is located at the center of the spot of the energy ray, and the wavelength λ = 2
An excimer laser having a pulse width of 48 nm and a pulse width of 25 nsec has an energy density of 80 mJ / cm ² and a beam diameter of 10 mm.
Irradiation was performed at * 30 mm (diameter at which 1 / e ^{2 of the} peak energy), and the site was heated to near the Curie temperature.

At the same time as the irradiation, an external magnetic field of about 1.5 kGauss was applied in the circumferential direction of the magnetic recording medium by a permanent magnet in a direction opposite to the initial magnetization direction to try to transfer a magnetization pattern. When irradiating with energy rays, clean air at a temperature of about 20 ° C. is directly applied to the back surface of the mask directly at 2 kgf / cm 2.
^The laser irradiation is performed by arranging the air gun so as to hit at ² and the laser irradiation is performed at the frequency of 10 Hz, 30 pulses and the required time of 3 seconds while performing the above-mentioned heat removal and setting the angle of the magnetic disk every 12 °. To form a magnetization pattern.

The precision of the formed magnetic pattern was determined by developing the magnetic pattern with a magnetic developer, and using an optical microscope at a magnification of 1600 times, the minimum width of 1 μm at the mask was actually what μm.
Was checked by observing any 10 points on the disk. Table 1 shows the measured values at each measurement point and the result of integrating the difference between the measured value and the target value at each measurement point. The smaller the integrated value, the closer to the target value, the more preferable.

[0105]

[Table 1]

Example 2 In the same manner as in Example 1 except that clean air was applied not to the back surface of the mask but to the portion of the magnetic recording medium holding means to which the energy beam was directly irradiated when irradiating the energy beam with the magnetic pattern. Attempted transcription. The accuracy of forming the magnetization pattern was evaluated in the same manner as in Example 1. Table 1 shows the results.
Shown in

Example 3 In the same manner as in Example 1, except that clean air was applied to both the back surface of the mask and the portion of the magnetic recording medium holding means to which the energy beam was directly irradiated when irradiating the energy beam. I tried to transfer the pattern. The accuracy of forming the magnetization pattern was evaluated in the same manner as in Example 1. Table-Results
It is shown in FIG.

Comparative Example 1 A transfer of a magnetic pattern to a magnetic disk was attempted in the same manner as in Example 1 except that cooling with clean air was not performed during irradiation with energy rays. The accuracy of forming the magnetization pattern was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0109]

As described above, according to the present invention,
Provided are a method and apparatus for forming a magnetized pattern that can efficiently form a highly accurate pattern with small dimensional errors, and that does not damage the medium or the mask, and that causes few defects.
As a result, a magnetic recording medium and a magnetic recording device capable of high-density recording can be provided in a short time and at low cost.

[Brief description of the drawings]

FIG. 1 is a plan view for explaining mask means used in Examples and Comparative Examples of the present invention.

FIG. 2 is a diagram illustrating an example of a method for forming a magnetic pattern according to the present invention.

FIG. 3 is a diagram for explaining another example of the method for forming a magnetic pattern according to the present invention.

[Explanation of symbols]

 Reference Signs List 101 magnetic disk 102 photomask 103 pulsed laser beam 104 external magnetic field 105 photopolymer 106 photomask 107 object beam 108 prism 109 reference beam 110 light source 111 reflector 120 spindle 121 turntable 122 spacer 123 presser plate 130, 130 ', 130 " Air gun 131, 131 ', 130 "clean air piping

Claims (13)

[Claims] 1. A method for irradiating a magnetic recording medium comprising at least one layer of a magnetic thin film on a substrate with a pulsed energy beam through a mask means and applying an external magnetic field to form a magnetization pattern. A method for forming a magnetic pattern on a magnetic recording medium, comprising: cooling a mask means when irradiating an energy beam. 2. A method for irradiating a magnetic recording medium having at least one layer of magnetic thin film on a substrate with a pulsed energy beam through a mask means and applying an external magnetic field to form a magnetization pattern. A method for forming a magnetic pattern of a magnetic recording medium, comprising: cooling a medium holding unit when irradiating an energy ray while holding the magnetic recording medium with the medium holding unit. 3. The method according to claim 1, wherein the magnetic thin film of the magnetic recording medium is previously uniformly magnetized by an external magnetic field. 4. The method for forming a magnetic pattern of a magnetic recording medium according to claim 1, wherein an external magnetic field is applied simultaneously with the irradiation of the pulsed energy beam. 5. A magnetic pattern is formed by irradiating a pulsed energy beam to locally demagnetize, thereby forming a magnetization pattern.
5. The method for forming a magnetic pattern of a magnetic recording medium according to any one of claims 4 to 4. 6. The wavelength of the pulsed energy beam is 1100.
The method for forming a magnetic pattern of a magnetic recording medium according to claim 1, wherein the thickness is not more than nm. 7. The method according to claim 1, wherein the pulsed energy beam is a laser beam. 8. The method according to claim 1, wherein the magnetization pattern is a servo pattern for tracking a write / read head on a data track on a magnetic recording medium, or a preparation pattern for writing a servo pattern. A method for forming a magnetization pattern of a magnetic recording medium. 9. A method of irradiating a magnetic recording medium having at least one layer of a magnetic thin film on a substrate with a pulsed energy beam through a mask means and applying an external magnetic field to form a magnetization pattern. An apparatus for forming a magnetic pattern, comprising: a mask unit; an external magnetic field applying unit; and a cooling unit for the mask unit. 10. A method for irradiating a magnetic recording medium having at least one layer of a magnetic thin film on a substrate with a pulsed energy beam through a mask means and applying an external magnetic field to form a magnetization pattern. A magnetic pattern for a magnetic recording medium, comprising: a medium holding unit for holding a magnetic recording medium; a mask unit; an external magnetic field applying unit; and a cooling unit for cooling the medium holding unit. Forming equipment. 11. A magnetic recording medium, wherein a magnetic pattern is formed by the method of forming a magnetic pattern according to claim 1. Description: 12. A magnetic recording medium, a driving unit for driving the magnetic recording medium in a recording direction, a magnetic head including a recording unit and a reproducing unit, means for moving the magnetic head relative to the magnetic recording medium, 9. A magnetic recording apparatus comprising a recording / reproducing signal processing means for inputting a recording signal to a head and outputting a reproducing signal from a magnetic head, wherein the magnetic recording medium is formed of a magnetic pattern according to claim 1. A magnetic recording device, wherein a magnetization pattern is formed by a method. 13. After assembling the magnetic recording medium into the device,
The magnetization pattern is reproduced by a magnetic head to obtain a signal,
13. The magnetic recording apparatus according to claim 12, wherein a servo burst signal is recorded by the magnetic head based on the signal.