JP2003272137A - Method of forming magnetization pattern of magnetic recording medium, magnetic recording medium, magnetic recorder, and mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetization pattern forming method which can precisely and efficiently form a fine magnetization pattern at low cost without using the energy ray of high power and to provide a mask used therefor, in the magnetization pattern forming technique which forms the magnetization pattern on a magnetic recording medium by using a combination of local heating and external magnetic field application, and to inexpensively provide the magnetic recording medium with less defects which makes high density recording possible and a magnetic recorder in a short period. <P>SOLUTION: The magnetization pattern consisting of a first magnetization region having an initial magnetization direction and a second magnetization region having a magnetization direction opposite to the initial magnetizing direction is obtained by: forming the initial magnetization region having the initial magnetizing direction on a magnetic recording medium with a magnetic layer by applying a first external magnetic field to magnetize the magnetic layer in a desired direction in advance; and applying thereafter a second external magnetic field while irradiating the initial magnetization region of the magnetic layer with an energy for local heating to reverse the magnetization of the heated part. The second magnetization region exceeds 50% of the initial magnetization region. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a magnetization pattern of a magnetic recording medium such as a magnetic disk used in a magnetic recording device, a magnetic recording medium produced by the method, and a magnetic recording device. It also relates to a mask used for forming a predetermined pattern.

[0002]

2. Description of the Related Art A magnetic recording device represented by a magnetic disk device (hard disk drive) is widely used as an external storage device of an information processing device such as a computer, and in recent years, it is a recording device for a moving image recording device or a set top box. It is also being used as a device.

A magnetic disk device usually has a shaft for fixing one or a plurality of magnetic disks in a skewered shape,
A motor for rotating a magnetic disk joined to the shaft through a bearing, a magnetic head used for recording and / or reproducing, an arm to which the head is attached, and a head for mounting the head on a magnetic recording medium. An actuator that can be moved to any position. The recording / reproducing head is usually a flying head, which moves on the magnetic recording medium with a constant flying height. In addition to the flying head, use of a contact head (contact head) has also been proposed in order to further reduce the distance to the medium.

In a magnetic recording medium mounted on a magnetic disk device, a NiP layer is generally formed on the surface of a substrate made of an aluminum alloy or the like, and after performing a required smoothing treatment, a texturing treatment, etc., a NiP layer is formed thereon. It is manufactured by sequentially forming a metal underlayer, a magnetic layer (information recording layer), a protective layer, a lubricating layer and the like. Alternatively, it is manufactured by sequentially forming a metal underlayer, a magnetic layer (information recording layer), a protective layer, a lubricating layer, etc. on the surface of a substrate made of glass or the like. The magnetic recording medium includes an in-plane magnetic recording medium and a perpendicular magnetic recording medium. Longitudinal recording is usually performed on the longitudinal magnetic recording medium.

The density of magnetic recording media has been increasing every year, and there are various techniques for realizing this. For example, improvements such as making the flying height of the magnetic head smaller, adopting a GMR head as the magnetic head, and increasing the coercive force of the magnetic material used for the recording layer of the magnetic disk, and the information recording track of the magnetic disk Attempts have been made to reduce the interval between. For example, 100 Gb
To achieve it / inch ² , the track density is 10
0 ktpi or more is required.

A control magnetization pattern for controlling the magnetic head is formed on each track. For example, it is a signal used for position control of the magnetic head or a signal used for synchronization control. When the distance between the information recording tracks is narrowed and the number of tracks is increased, the signal used for position control of the data recording / reproducing head (hereinafter, also referred to as “servo signal”) is also aligned in the radial direction of the disk. On the other hand, it must be densely provided, that is, more, so that precise control can be performed.

Further, it is desired to increase the data recording capacity by reducing the area other than the area used for data recording, that is, the area used for servo signals and the gap between the servo area and the data recording area to widen the data recording area. Is also a big request. For this purpose, it is necessary to increase the output of the servo signal and the accuracy of the synchronization signal. The method widely used in the past is to make a hole in the vicinity of the head actuator of a drive (magnetic recording device), insert a pin with an encoder in that part, and engage the actuator with the pin to make the head accurate. It drives to a position and records a servo signal.
However, since the center of gravity of the positioning mechanism and the center of gravity of the actuator are different from each other, highly accurate track position control cannot be performed, and it is difficult to accurately record the servo signal.

On the other hand, a technique has also been proposed in which a magnetic disk is irradiated with a laser beam to locally deform the disk surface to form physical unevenness, thereby forming an uneven servo signal. However, the flying head becomes unstable due to the unevenness, which adversely affects recording / reproduction. It is necessary to use a laser beam having a large power to form the unevenness, which is costly, and it takes time to form the unevenness one by one. There was such a problem.

Therefore, a new servo signal forming method has been proposed. One example is a method in which a servo pattern is formed on a master disk having a magnetic layer with high coercive force, the master disk is brought into close contact with a magnetic recording medium, and a magnetic field is transferred by applying an auxiliary magnetic field from the outside (USP.
5,991,104). Another example is a method in which the medium is magnetized in one direction in advance, a soft magnetic layer having a high magnetic permeability and a low coercive force is patterned on the master disk, and the master disk is brought into close contact with the medium and an external magnetic field is applied. . The soft magnetic layer acts as a shield, and the magnetization pattern is transferred to the unshielded region (Japanese Patent Laid-Open No. 50-6
0212 (USP 3,869,711), JP-A-10-40544 (EP915456), "R"
eadback Properties of Novel Magnetic Contact Dupli
cation Signals with High Recording Density FD "(Sug
ita, R et.al, Digest of InterMag 2000, GP-06, IEEE
Issue))).

The present technique uses a master disk to form a magnetization pattern on a medium by a strong magnetic field. Generally, the strength of the magnetic field depends on the distance, and therefore, when recording the magnetization pattern by the magnetic field, the pattern boundary is apt to be unclear due to the leakage magnetic field. Therefore, it is essential to bring the master disk and the medium into close contact with each other in order to minimize the leakage magnetic field. Further, as the pattern becomes finer, it is necessary to completely adhere to each other without a gap, and usually, both are pressure-bonded by vacuum suction or the like.

Further, the higher the coercive force of the medium, the larger the magnetic field used for transfer and the larger the leakage magnetic field.
Furthermore, it is necessary to make them adhere completely. Therefore, the above technology
It is easy to apply to a magnetic disk with low coercive force and a flexible disk that is easy to press-bond, but it is very suitable for a magnetic disk using a hard substrate and having a coercive force of 3000 Oe or more for high density recording. It's difficult.

That is, the magnetic disk of the hard substrate has a risk that a minute dust or the like may be sandwiched between the hard disk and the medium to cause a defect, or an expensive master disk may be damaged. In particular, in the case of a glass substrate, there are problems that the adhesion is insufficient due to the inclusion of dust, magnetic transfer cannot be performed, and cracks occur in the magnetic recording medium. Also, JP-A-50-60212 (USP 3,869,711)
The technique described in (No.) has a problem that a pattern having an oblique angle with respect to the track direction of the disk can be recorded but only a pattern having a weak signal strength can be formed. For a magnetic recording medium having a high coercive force of 2000 to 2500 Oe or more, in order to secure the magnetic field strength of transfer, the pattern ferromagnetic material (shield material) of the master disk is a saturated magnetic flux such as permalloy or sendust. There is no choice but to use a soft magnetic material with a high density.

However, in the oblique pattern, the magnetic field of the magnetization reversal is perpendicular to the gap formed by the ferromagnetic layer of the master disk, and the magnetization cannot be tilted in a desired direction. As a result, a part of the magnetic field escapes to the ferromagnetic layer, and it is difficult to apply a sufficient magnetic field to a desired portion during magnetic transfer, and it is difficult to form a sufficient magnetization reversal pattern and it is difficult to obtain high signal strength. Such an oblique magnetization pattern causes the reproduction output to be reduced more than azimuth loss with respect to the pattern perpendicular to the track.

On the other hand, Japanese Patent Application No. 2000-13460
The techniques described in the specifications of No. 8 and Japanese Patent Application No. 2000-134611 form a magnetization pattern on a magnetic recording medium by combining local heating and application of an external magnetic field. For example, the medium is magnetized in one direction in advance, and an energy ray or the like is irradiated through a patterned mask to locally heat the medium, and an external magnetic field is applied while lowering the coercive force of the heated region to Recording is performed by an external magnetic field to form a magnetization pattern.

According to the present technology, since the coercive force is lowered by heating and the external magnetic field is applied, the external magnetic field does not need to be higher than the coercive force of the medium, and recording can be performed with a weak magnetic field. Since the area to be recorded is limited to the heating area and the area other than the heating area is not recorded even when a magnetic field is applied, a clear magnetization pattern can be recorded without bringing a mask or the like into close contact with the medium.
Therefore, the medium and the mask are not damaged by the pressure bonding, and the defects of the medium are not increased.

Further, according to the present technique, a diagonal magnetization pattern can be formed well. This is because it is not necessary to shield the external magnetic field with the soft magnetic material of the master disk as in the conventional case.

[0017]

As described above, the above-mentioned magnetization pattern forming technique can efficiently form various fine magnetization patterns with high precision, and increase the defects of the medium without damaging the medium or the mask. It is an excellent technology that never happens. However, in the present technology, it is necessary to use a high-power laser source or the like in order to increase productivity, but on the other hand, if the laser output is too high, there is a conflicting problem that the medium is likely to be damaged. It was

The mask used in the present technology usually has a transparent portion and a non-transparent portion for energy rays. Generally, a metal such as chromium is formed by sputtering on a transparent master such as quartz glass or soda lime glass. Then, a photoresist is applied thereon, and desired transmissive portions and non-transmissive portions are formed by photolithography and etching. In this case, the portion having the chrome layer on the master is the energy ray non-transmissive portion and the portion only on the master is the transparent portion.

In the mask thus formed, most of the pattern area is a non-transmissive portion covered with a chrome layer, and a part thereof is a transmissive portion. The energy ray applied to the non-transmissive portion is shielded from light and is not used for heating the magnetic layer of the magnetic recording medium. As described above, since only a small part of the energy rays with which the mask is irradiated contributes to the formation of the magnetization pattern, an energy ray source having high output (high power, high intensity, high energy density) is required. If the output is too low, heating of the magnetic layer will be insufficient and the desired magnetization pattern may not be formed accurately.

Particularly in recent years, the pattern width to be formed is becoming narrower. Generally, the narrower the pattern width is, the more difficult it is for the energy rays to pass through. Therefore, in order to heat the magnetic layer to the same temperature, higher power is required. It's coming. However, high-power energy source is generally expensive. Further, there is a problem that the mask and the magnetic recording medium are more likely to be damaged as the energy beam becomes higher in power. For example, the chrome layer, which is a non-transmissive portion, absorbs energy rays and expands due to the generated heat, and is peeled off, so that the mask cannot be continuously used. Alternatively, the magnetic layer or the like of the magnetic recording medium is melted by the energy rays, and the surface of the medium is deformed to form irregularities, resulting in defects.

Further, according to the study by the present inventors, it was found that the medium is more likely to be damaged when the area irradiated with the energy rays is small and the periphery is shielded widely. It is considered that the reason for this is that if the energy beam irradiation area is small, the difference between the heat generated in the medium and the ambient temperature due to the irradiated energy becomes large and the thermal shock (thermal shock) becomes large. .

In view of the above-mentioned problems, the present invention is a technique for forming a magnetization pattern on a magnetic recording medium by combining local heating and application of an external magnetic field, whereby a fine magnetization pattern can be accurately formed without using a high power energy ray. An object of the present invention is to provide a magnetic pattern forming method that can be efficiently formed at low cost and a mask used therefor. Consequently, it is an object of the present invention to provide a magnetic recording medium and a magnetic recording device which have less defects and are capable of high density recording in a short time and at low cost.

[0023]

SUMMARY OF THE INVENTION The gist of the present invention is to apply a first external magnetic field to a magnetic recording medium having a magnetic layer to magnetize the magnetic layer in a desired direction in advance so that the initial magnetization direction. After the formation of the initial magnetization region having the magnetic field, the energy layer is irradiated to locally heat the initial magnetization region of the magnetic layer, and at the same time, the second external magnetic field is applied to reverse the magnetization of the heating portion, thereby A method of forming a magnetization pattern comprising a first magnetization region having a direction and a second magnetization region having a magnetization direction opposite to the initial magnetization direction, wherein the second magnetization region exceeds 50% of the initial magnetization region. It lies in a characteristic method of forming a magnetic pattern.

Another subject matter of the present invention resides in a magnetic recording medium characterized in that a magnetic pattern is formed by the above magnetic pattern forming method. Still another subject matter of the present invention is a magnetic recording medium in which a magnetic pattern is formed by the above magnetic pattern forming method, a drive unit for driving the magnetic recording medium in the recording direction, and a magnetic head including a recording unit and a reproducing unit. A magnetic recording device comprising means for moving the magnetic head relative to the 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. Exist in.

Still another subject matter of the present invention is to apply a first external magnetic field to a magnetic recording medium having a magnetic layer to magnetize the magnetic layer in a desired direction in advance so as to have an initial magnetization direction. After forming the magnetized region, an energy ray is irradiated through the mask to locally heat the initial magnetized region of the magnetic layer, and at the same time, a second external magnetic field is applied to reverse the magnetization of the heating portion, thereby initializing A mask used in a method of forming a magnetization pattern comprising a first magnetization region having a magnetization direction and a second magnetization region having a magnetization direction opposite to an initial magnetization direction, the mask being formed according to a magnetization pattern to be formed. A mask is characterized in that it has a pattern region consisting of an energy ray transmitting portion and a non-transmitting portion, and the area of the energy ray transmitting portion in the pattern area exceeds 50%.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. According to the present invention, after the initial magnetization region is formed on the magnetic recording medium by the first external magnetic field, the heating pattern is locally heated by the energy beam and a part of the magnetization is inverted by the second external magnetic field to form the magnetization pattern. It is characterized in that an area larger than 50% is locally heated to reverse the magnetization.

As described above, the mask which has been usually used conventionally has a non-transmissive portion in which most of the pattern area is covered with the chrome layer, and the transmissive portion is a very small portion. For example 40%
It is a degree. Therefore, in the conventional magnetization pattern forming method using this, only a small area corresponding to the transmissive portion in the initially magnetized region is locally heated and the magnetization is inverted.

On the other hand, according to the present invention, since the area to be locally heated by the energy rays is increased, the thermal stress generated in the medium by the applied energy can be suppressed to be small and the medium is less likely to be damaged. be able to. Such a magnetization pattern forming method can be easily realized by using a mask. A mask suitable for this method, which has a pattern region including an energy ray transmitting portion and an energy ray non-transmitting portion according to a magnetization pattern to be formed, and the area of the energy ray transmitting portion in the pattern area exceeds 50%. Can be used.

According to this, the number of energy rays shielded by the non-transmissive portion is reduced, and most of the energy rays applied to the mask can be used for heating the magnetic layer, and the energy rays can be used efficiently. An energy ray source with lower output than before can be applied. Therefore, the cost can be kept low. Particularly, it is highly effective when applied to a medium having a narrow pattern width for high density recording, which has conventionally required a higher power energy ray, for example, a medium having a minimum pattern width of 1 μm or less.

Further, conventionally, there has been a problem that the mask and the magnetic recording medium are more likely to be damaged as the energy beam becomes higher in power, but according to the present invention, the damage to the mask and the magnetic recording medium can be suppressed. Therefore, the present invention is a technique of forming a magnetization pattern on a magnetic recording medium by combining local heating and application of an external magnetic field, and accurately forms a fine magnetization pattern without using a high power energy ray.
It is possible to provide a method for forming a magnetic pattern that can be efficiently formed at low cost and a mask used for the method. As a result, it is possible to provide a magnetic recording medium and a magnetic recording device, which have less defects and enable high-density recording, in a short time and at low cost.

In the present invention, preferably, an area larger than 55% of the initial magnetization region is locally heated to reverse the magnetization. More preferably, the area is larger than 70%. Similarly, in the mask of the present invention, preferably, the area of the energy ray transmitting portion in the pattern region exceeds 55%. It is more preferably more than 70%.

A more detailed description will be given with reference to the drawings. Figure 5
FIG. 3 is a schematic diagram of a magnetic disk on which a control magnetization pattern such as a servo pattern is formed. The magnetic disk (magnetic recording medium) 1 shown in FIG. 5A includes an area (pattern area) 31 in which a magnetic pattern is formed and an area 32 in which no magnetic pattern is formed. In the pattern area 31, a curved control pattern (spokes) 33 that extends in a substantially radial pattern is usually repeatedly formed at predetermined intervals in the circumferential direction of the magnetic disk 1.

The control pattern (spoke) has control information for the recording / reproducing magnetic head. For example, it includes a servo pattern for controlling the position of the recording / reproducing magnetic head or a reference pattern for recording the servo pattern. An example of an enlarged view of a part of the control pattern (spoke) 33 is shown in FIG.
It shows in (b). In this example, the pattern is inclined at a predetermined angle with respect to the circumferential direction. In the present invention, the first magnetization region 41 and the second magnetization region 42 are formed.

That is, first, the first external magnetic field is applied to the magnetic disk, and the entire magnetization pattern forming region 31 is
It is initially magnetized uniformly in the direction of the first magnetized region 41 and becomes an initial magnetized region. Next, the region to be the second magnetized region 42 is irradiated with the energy rays and heated, and at the same time, the opposite second external magnetic field is applied. In this way, the second magnetization region 42 opposite to the initial magnetization is formed, and the remaining portion becomes the first magnetization region 41.

At this time, the area other than the control pattern (spoke) 33 which is the magnetization pattern forming area 31 is the second area.
It becomes the magnetized region 42. According to the present invention, as described above, it is possible to suppress damage to the medium due to thermal stress by heating a large number of regions exceeding 50% in the heating step. The pattern may have various shapes and numbers, but is not particularly limited in the present invention.

Next, a method for forming a magnetic pattern and a mask according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining an example of a magnetization pattern forming method according to the present invention. The in-plane magnetic disk 1 is magnetized in advance in one circumferential direction by an external magnetic field. After that, the mask 2 is placed on the magnetic disk 1 and fixed by a retaining screw (not shown). The mask 2 comprises a transparent substrate 6 made of quartz and a non-transmissive layer 7. Recesses are formed on the surface of the substrate 6 according to the magnetization pattern to be formed, and a non-transmissive layer 7 made of a metal such as chromium is formed in the recesses. Further, on the surface of the mask 2 for the magnetic disk 1, for example, Ti
A dielectric layer (non-reflection coating) 8 in which O ₂ and SiO ₂ are laminated is provided.

A laser beam 4 is irradiated onto this, and at the same time, an external magnetic field 3 is applied. The irradiated energy ray is blocked by the non-transmissive layer 6, and the energy ray transmitted through the transmissive portion forms a heating area on the magnetic disk. The laser beam 4 may be expanded / reduced through a mask having a transparent portion similar in shape to the region to be heated. A second external magnetic field is applied to this heating region to form a magnetization pattern. It should be noted that this external magnetic field has a direction opposite to that of the external magnetic field when magnetized uniformly in advance. In this way, a fine magnetization pattern can be formed efficiently and accurately.
At this time, the distance between the mask and the magnetic disk does not have to be constant over the entire surface, and the distance may be appropriately adjusted by a spacer or the like. Thereby, the transmission / non-transmission of the energy rays can be easily adjusted without finely adjusting the power of the energy rays or the pattern line width of the mask by the line width of the pattern, and a desired magnetization pattern can be obtained.

In the present invention, the so-called lift-off method is preferably used for mask production. According to the conventional general mask manufacturing method, in order to make the transmissive portion have a large area, it is necessary to uniformly remove the chromium layer by etching over the large area, which requires much cost and time. On the other hand, the lift-off method involves the following steps. Generally, a photoresist is applied on a transparent master such as quartz glass or soda lime glass, and then irregularities are formed by photolithography. Next, a metal such as chromium is formed by sputtering. After that, when the photoresist is removed, the chrome layer on the photoresist layer is also removed,
Only the chromium layer formed in the concave portion without the photoresist remains convex.

The method is first preferred in that it does not require etching of the chromium layer. Further, this method has an advantage that a pattern having a narrow minimum pattern width can be easily formed as compared with the conventional method. Further, it is particularly preferable to use a mask as shown in the drawing, in which a concave portion corresponding to the magnetization pattern to be formed is provided in the base and a non-transmissive layer is formed at least on the concave portion.

The present mask has an advantage that the non-transmissive layer is less likely to be peeled from the substrate. In the conventional mask, the non-transmissive layer is formed on the flat plate-shaped substrate, but according to this mask, the substrate has the concave portion and the non-transmissive layer is formed in the concave portion, so that the anchor effect works. It is considered that the adhesion between the non-transmissive layer and the substrate is increased and the non-transmissive layer is less likely to peel off. Therefore, there is an advantage that the non-transmissive layer can be prevented from peeling from the substrate even when irradiated with high-energy energy rays, and the energy ray durability is enhanced.

In FIG. 1, the recess formed in the substrate 6 may have any shape as long as it has the effect of making the non-transmissive layer 7 less likely to peel off, and may have a rectangular, trapezoidal, or circular cross-sectional shape. It is considered that the deeper the depth of the recesses is, the higher the peeling-preventing effect is. However, it is preferably 10 μm or less. This is because if it is too deep, it takes time to form and the effect of preventing peeling is not greatly improved. The width of the recess is usually determined according to the pattern to be formed.

The surface of the non-transmissive layer 7 does not necessarily have to have the same height as the surface of the substrate 6. That is, it is not necessary to fill all the recesses on the base, or conversely, the recesses may be formed so as to be raised. However, if the portion formed on the recess is too large compared to the depth of the recess, the effect of preventing separation of the non-transmissive layer 7 becomes small, so the surface height of the non-transmissive layer is It is preferable that it is equal to or lower than the surface height of 6.

In many cases, a fluorine-based lubricant is coated on the magnetic recording medium, and the lubricant is evaporated by irradiation with a high-power energy beam, and the fluorine-based compound contained therein forms a metal. The non-permeable layer may be corroded. In order to prevent such corrosion, the height of the surface of the non-transmissive layer is preferably low and is preferably equal to or lower than the surface height of the substrate 6.

The material of the mask is not particularly limited as long as it can obtain sufficient transparency with respect to the used wavelength of energy rays, and glass, resin or the like can be used, but the transmittance is preferably 80% or more. , And more preferably 90% or more of non-magnetic material. By using such a material having high transmittance, the energy rays can be efficiently used. However, even a material having a high permeability has some absorption of energy rays, and therefore, it is necessary to have some resistance to energy rays and heat.

The mask is preferably made of a non-magnetic material. A magnetized pattern can be formed with uniform clarity in any pattern shape, and a uniform and strong reproduction signal can be obtained. In the case of a mask containing a ferromagnetic material, magnetization may disturb the magnetic field distribution. Due to the property of ferromagnetism, in the radial direction of the magnetic disk or in the case of a pattern shape obliquely inclined from the arc-shaped pattern extending in the radial direction, the magnetic domains do not sufficiently oppose each other at the magnetization transition portion, and thus it is difficult to obtain a good signal.

From the above reasons, glass-based materials are preferable, and further, in order to form a fine pattern, it is preferable to use quartz glass which can efficiently handle short wavelength energy rays. Although quartz glass is relatively expensive, it has an advantage that energy rays of a short wavelength of 300 nm or less, which are particularly easy to perform microfabrication, can be used because they have high transparency to energy rays in the ultraviolet region. When using an energy ray having a wavelength longer than this, it is preferable to use an optical glass in terms of cost. Although the thickness of the substrate is not limited, it is usually preferably about 1 to 10 mm so that the substrate does not bend and a stable flatness is obtained.

Regarding flatness, the smaller the undulation, the more preferable from the viewpoint of correcting the distortion of the disk at the time of mounting, and the undulation is preferably 2 μm or less in order to obtain a pattern of submicron or less. The material of the non-transmissive layer may be any material and film thickness that does not substantially transmit the energy rays used, and inorganic compounds such as metals, semimetals, dielectrics, organic compounds, etc. can be used, but durability against energy rays It is preferable to use an inorganic compound because it has high properties and has good adhesion to a glass material. Here, the metal or the semimetal includes an alloy. In general, a metal is preferable in that a film formation speed is generally higher when a film is formed by a sputtering method or the like than a dielectric material and a mask manufacturing time can be shortened.

Examples of the metal or metalloid are Cr,
Al, Pt, Au, Ag, Cu, Pd, Ti, Ni, T
a, Mg, Se, Hf, V, Nb, Ru, W, Mn, R
e, Fe, Co, Rh, Ir, Zn, Cd, Ga, I
Examples thereof include n, Si, Ge, Te, Pb, Po, Sn, Bi and alloys containing these as the main components. The main component means a case where those elements occupy 50 atomic% or more in the alloy.

A material having a high reflectance is preferably used for the non-transmissive layer. For example, Cr, Al, Pt, Au, Ag, C
Examples thereof include u, Pd, Ti, Si, Ni, Ta, and alloys containing these as main components. Especially Si, Al, Pt, A
u, Ag, Cu, Cr and alloys containing these as main components are preferable. Pt and Pt alloys are preferable because they have high corrosion resistance and are less likely to be corroded by the fluorine compound generated by the decomposition of the lubricant. Cr and Cr alloys are preferable because they have particularly high adhesion to glass and high light-shielding properties.

Among them, Si compounds such as Si and MoSiN are particularly preferable because they have high reflectance, high adhesion to glass, and are chemically stable. In addition, the non-transmissive layer may be a plurality of layers of two or more layers if necessary. Alternatively, another layer may be provided on the non-transmissive layer. For example,
A layer of chromium oxide or the like may be provided to reduce the reflectance of the surface of the non-transmissive layer.

The film thickness of the non-transmissive layer may be such that sufficient non-transparency (energy ray shielding property) and desired reflectance and energy ray durability can be obtained. Although it depends on the method, it is preferably about 40 nm or more. When the durability against energy rays is emphasized, the thicker the thickness, the more preferable it is. However, if it is too thick, the film formation time becomes too long, so 500 nm or less is preferable.

When the surface of the non-transmissive layer is higher than the surface of the substrate, a material that transmits energy rays may be embedded between the plurality of non-transmissive layers to make the mask surface flatter. A dielectric layer is preferably formed on the outermost layer of the surface of the mask facing the magnetic recording medium. This is also commonly referred to as an antireflection coating. By performing such a treatment, the reflectance of the mask can be reduced, the formation of interference fringes can be weakened, and the energy rays can be effectively used.

However, even on the surface of the mask with respect to the magnetic recording medium, it is not always necessary to form the dielectric layer as the outermost layer except for the region corresponding to the magnetization pattern forming region.
Conventionally, the surface of the mask with respect to the magnetic recording medium usually has a concavo-convex structure in which a non-transmissive layer is formed on a light transmissive substrate, but stress is concentrated on the corners of the surface with such concavities and convexities. There is a problem that the dielectric layer is easily peeled off as compared with a flat surface. However, according to the present mask, since the mask surface can be made flat, there is no such problem,
There is an advantage that the dielectric layer is difficult to peel off.

A mask in which the outermost layer on the side opposite to the magnetic recording medium is also a dielectric layer is more preferable because it can further reduce reflection. The dielectric layer is different in type, thickness, laminating method, etc. depending on its target wavelength, but in general, it has high transparency to the wavelength of the energy rays used,
It is required to have an appropriate refractive index and a high melting point that can withstand irradiation of energy rays, and oxides and sulfides of metals and semiconductors,
Nitride or fluoride such as Ca, Mg, Al or Li is used. These oxides, sulfides, nitrides, and fluorides do not necessarily have to have a stoichiometric composition, and it is also effective to control the composition or mix them for controlling the refractive index and the like.

For example, MgF₂, ThOF₂, SiO₂,
SiO, TiO₂, Ta₂O_Five, ZrO ₂, CeO₂, Mo
O₂, Al₂O₃, La₂O₃, Cu₂O, WO₃, Si
₃N_Four, ZnS, ZnSe, CdS, CdSe, InS.
Any one layer or two or more layers may be formed. Especially MgF
₂, ThOF₂, SiO₂, TiO₂, CeO₂, Al
₂O₃, ZnS are used. This dielectric layer is
It may be a composite dielectric containing at least one kind, and its purity is also optional.
It means that you can choose it according to your purpose.

Further, the present mask is highly effective when applied to a method of irradiating the mask with pulsed energy rays, which generally has a higher power peak value than continuous energy rays and is apt to damage the mask. Particularly, it is a case where the power per pulse of the pulsed energy beam is 10 mJ / cm ² or more and 1000 mJ / cm ² or less. Next, a method for manufacturing the present mask will be described.

The recesses corresponding to the pattern on the mask substrate can be manufactured by subjecting the mask substrate to chemical etching or physical etching. Chemical etching is a method of performing etching by corroding the mask substrate by causing a chemical reaction, and physical etching is a method of physically scraping off the surface of the mask by using a machine or the like.

The method by chemical etching is preferable in that a fine pattern can be formed and the mask according to the present invention can be formed easily and inexpensively. The portion etched in this way becomes a recess. As a chemical etching procedure, prior to the etching treatment,
First, after forming a photoresist layer on a mask substrate, usually exposure and development processing (photolithography)
As a result, irregularities corresponding to the magnetization pattern are formed on the photoresist layer. After that, etching treatment is performed. There are roughly two types of etching treatments, one is wet etching and the other is dry etching.

The wet etching is carried out by immersing the mask substrate having a photoresist layer corresponding to the above-mentioned magnetization pattern in an aqueous solution containing acidic fluorine ions such as ammonium acid fluoride to corrode and dissolve the exposed portion of the mask substrate. Is. According to this method, corrosion proceeds isotropically,
Usually, the recess has a semicircular cross section. Dry etching is a method in which a mask substrate having a photoresist layer corresponding to the above-described magnetization pattern is caused to act on the exposed portion of the mask substrate with a plasma-containing fluoride-containing gas to gasify and remove the substrate. According to this method, the etching rate varies depending on the gas particle arrival direction, and usually the etching proceeds specifically in the depth direction. Therefore, the cross section of the recess is usually formed in a shape close to a rectangle.

In the manufacture of this mask, it is possible to more stably form a mask having a fine pattern.
Dry etching is preferably used because the roughness of the groove bottom can be controlled appropriately. Also,
In the present invention, when dry etching is performed using a gas containing a fluoride, it is possible to stably etch deep trenches by using a chromium layer as a shielding material instead of the photoresist. This is because the dry etching selectively etches the oxide and has an extremely low etching rate for metal.

In this method, first, a metallic chromium layer is formed on quartz glass, a photoresist is applied, and a desired pattern is formed using an electron beam drawing apparatus or a laser drawing apparatus. Next, the photoresist is developed to remove the photoresist in the drawing portion, and further the chromium in the drawing portion is removed by an etching solution for chromium containing cerium nitrate or the like. The etching process can also be performed by a dry etching method using reactive ion etching (RIE). Then, the photoresist layer is removed with an organic solvent such as acetone. The steps up to this point are the same as the conventional manufacturing steps. Next, by using the thus formed chromium pattern as a shielding material, further reactive ion etching (RIE) is performed to etch the mask substrate to form a recess. According to this method, it is possible to form a rectangular, V-shaped or trapezoidal groove.

As described above, according to the present mask, the non-transmissive layer can be prevented from peeling off from the substrate even when irradiated with a high power energy ray, and the energy ray durability is enhanced. Next, a method for forming a magnetic pattern according to the present invention will be described. First, a technique of forming a magnetization pattern on a magnetic recording medium by combining local heating and application of an external magnetic field according to the present invention will be described.

In the method for forming a magnetic pattern of the present invention, preferably, the first external magnetic field is applied to uniformly magnetize the magnetic layer in a desired direction in advance, and then the magnetic layer is locally heated and at the same time the second external magnetic field is applied. Is applied to magnetize the heating portion in a direction opposite to the desired direction to form a magnetization pattern. As a result, magnetic domains in opposite directions are clearly formed, so that a magnetic pattern having a high signal strength and a good C / N and S / N can be obtained.

First, a strong first external magnetic field is applied to the magnetic recording medium to uniformly magnetize the entire magnetic layer in a desired magnetization direction. A magnetic head may be used as the means for applying the first external magnetic field, or an electromagnet or a permanent magnet may be arranged so as to generate a magnetic field in a desired magnetization direction. Further, these means may be used in combination. In the case of a medium having an easy axis of magnetization in the in-plane direction, the desired magnetization direction is the same as or opposite to the running direction of the data recording / reproducing head (the relative movement direction of the medium and the head), When the easy axis of magnetization is perpendicular to the in-plane direction, it is either in the vertical direction (upward or downward). Therefore, the first external magnetic field is applied so as to be magnetized as such. When the medium has a disk shape, the application direction of the first external magnetic field is preferably the circumferential direction, the radial direction, or the direction perpendicular to the plate surface.

Further, to uniformly magnetize the entire magnetic layer in a desired direction means to magnetize all of the magnetic layer in substantially the same direction, but not exactly all, but at least the region where the magnetization pattern is to be formed. It only has to be magnetized in the same direction. The strength of the first external magnetic field may be set according to the coercive force of the magnetic layer, but it is preferable to magnetize the magnetic layer with a magnetic field that is at least twice the coercive force (static coercive force) of the magnetic layer at room temperature. If it is weaker than this, the magnetization may be insufficient.
However, it is usually about 5 times or less the coercive force of the magnetic layer at room temperature due to the capability of the magnetizing device used for applying the magnetic field. Room temperature is, for example, 25 ° C. The coercive force of the magnetic recording medium is almost the same as the coercive force of the magnetic layer (recording layer).

The magnetic layer generally has a static coercive force (sometimes simply referred to as a coercive force) and a dynamic coercive force. For local heating, at least up to a temperature at which the dynamic coercive force of the magnetic layer is lowered to some extent. It only needs to be heated. Of course, you may heat to the temperature which static coercive force falls. Preferably 10
Heat to above 0 ° C. A magnetic layer that is affected by an external magnetic field at a heating temperature of less than 100 ° C. tends to have low magnetic domain stability at room temperature.

However, it is desirable that the heating temperature is as low as possible within the range where the desired decrease in coercive force can be obtained. For example, up to near the magnetization disappearance temperature or the Curie temperature of the magnetic layer. If the heating temperature is too high, heat diffusion easily occurs in areas other than the area to be heated, and the pattern may be blurred. In addition, the magnetic layer may be deformed. Furthermore, a lubricating layer made of a lubricant is usually formed on the surface of the magnetic recording medium, and the lower heating temperature is more preferable in order to prevent adverse effects such as deterioration of the lubricant due to heating. The heating may cause deterioration such as decomposition of the lubricant, or may be vaporized and reduced, and particularly in the case of proximity exposure, the vaporized lubricant may adhere to a mask or the like. Therefore, it is desirable that the heating temperature is as low as possible in order to industrially apply the magnetic pattern forming method of the present invention to a magnetic recording medium having a lubricating layer.

For this reason, it is preferable that the heating temperature is not higher than the Curie temperature of the magnetic layer. For example, the temperature is preferably 300 ° C or lower, more preferably 250 ° C or lower, and further preferably 200 ° C or lower. Then, the direction of the second external magnetic field applied simultaneously with the heating is generally opposite to the direction of the first external magnetic field. When the medium has a disk shape, it is preferable that the second external magnetic field is applied in the circumferential direction, the radial direction, or the direction perpendicular to the plate surface.

When the pulsed energy ray is used for heating, the second external magnetic field may be applied continuously or in a pulsed manner. When the second external magnetic field is a pulsed magnetic field, it may be only the pulsed magnetic field component or a combination of the pulsed magnetic field component and the static magnetic field component. At this time, the sum of the pulsed magnetic field component and the static magnetic field component is the strength of the second external magnetic field.

The stronger the maximum intensity of the second external magnetic field, the easier the formation of the magnetization pattern. The optimum strength varies depending on the characteristics of the magnetic layer of the magnetic recording medium, but when the second external magnetic field is a static magnetic field, it is preferably 1/8 or more of the coercive force (static coercive force) at room temperature. If it is weaker than this, the heating part 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 layer at room temperature is preferably 2/3 or less.
It is more preferable to set it to / 2 times or less. If it is larger than this, the magnetic domains around the heating portion may be affected.

When the second external magnetic field is a pulsed magnetic field, it is preferable that the coercive force at room temperature (static coercive force) is 2/3 or more. If it is too weak, the heated region may not be magnetized well. More preferably, it is 3/4 or more of the static coercive force at room temperature. A magnetic field stronger than the static coercive force at room temperature may be applied. However, the magnetic field is smaller than the dynamic coercive force of the magnetic layer at room temperature. This is because if the second external magnetic field is larger than this, it will affect the magnetization of the non-heated region.

In the present invention, the magnetic field strength value H (O
The value e) can be directly substituted by the value B (Gauss) of the magnetic flux density. Generally, there is a relationship of B = μH (where μ represents magnetic permeability), but since the magnetization pattern is usually formed in air, the magnetic permeability is 1, and the relationship of B = H is established. is there. As the means for applying the second external magnetic field, a magnetic head may be used, or a plurality of electromagnets or permanent magnets may be arranged and used so that a magnetic field is generated in a desired magnetization direction. You may use it in combination. Permanent magnets such as ferrite magnets, neodymium-based rare earth magnets, and samarium-cobalt-based rare earth magnets are suitable for efficiently magnetizing a high-coercivity medium suitable for high-density recording.

When the second external magnetic field is a pulsed magnetic field, only the pulsed magnetic field applying means may be used, or a combination of the pulsed magnetic field applying means and the static magnetic field applying means may be used. For example, in the former case, only a pulsed magnetic field is generated by an electromagnet or the like. For example, in the latter case, a static magnetic field of a certain magnitude is given by a permanent magnet or an electromagnet, and a magnetic field higher than that is applied in a pulse form by the electromagnet. It is preferable to use an air-core coil having a small inductance because the pulse width can be narrowed and the magnetic field application time can be shortened. Also, instead of the permanent magnet, another yoke-type electromagnet or the like may be used.

When the static magnetic field and the pulsed magnetic field are combined,
The magnetic field applied in pulses can be reduced. Generally, it becomes more difficult for the electromagnet to shorten the pulse width as the magnetic field increases, so that the pulse width is likely to be shortened accordingly. Alternatively, the pulsed magnetic field can be applied by a method in which a magnet that constantly generates a magnetic field is brought close to the magnetic recording medium for a short time. For example, the medium may be rotated at a speed higher than a predetermined speed while applying a magnetic field to a part of the magnetic recording medium with a permanent magnet.

When the second external magnetic field is a combination of a static magnetic field and a pulsed magnetic field, the magnetic field strength of the static magnetic field is made smaller than the static coercive force of the magnetic layer at room temperature. The static coercive force is preferably 2/3 or less, more preferably 1/2 times or less. If it is too large, it affects the formed magnetization pattern, which not only reduces the output but also deteriorates the modulation. There is no particular lower limit, but if it is too weak, the meaning of using a static magnetic field becomes small. Therefore, for example, it is set to 1/8 or more of the static coercive force of the magnetic layer at room temperature.

Next, the pulse width when the second external magnetic field is a pulsed magnetic field will be described. In the present invention, the pulse width of the pulsed magnetic field component of the second external magnetic field is simply referred to as the pulse width of the second external magnetic field. Here, the pulse width of the magnetic field refers to the half width. The pulse width of the second external magnetic field is usually 100 ms
ec or less. It is preferably 10 msec or less.
The shorter the pulse width of the second external magnetic field, the larger the upper limit of the magnetic field that can be applied. This is because the value of the dynamic coercive force changes depending on the application time of the magnetic field, and the shorter the pulse width of the second external magnetic field, the greater the dynamic coercive force of the magnetic layer at room temperature. It is more preferably 1 msec or less.

However, it is preferably 10 nsec or more. If it is too short, the dynamic coercive force will increase, and the second external magnetic field required to magnetize the heating region will increase. Further, although it depends on the magnitude of the magnetic field, it takes time for the magnetic field to rise and fall due to the characteristics of the electromagnet, so there is a limit to shortening the pulse width. More preferably, it is 100 nsec or more. Here, the pulse width of the magnetic field refers to the full width at half maximum.

When a pulsed energy ray is used for local heating, the pulse width of the second external magnetic field is set to be larger than the pulse width of the pulsed energy ray. This is because if it is less than this value, the magnetic field will change during local heating, and the magnetization pattern will not be formed well. Further, it is preferable that the pulsed energy ray and the pulsed second external magnetic field are synchronized and applied simultaneously. Normally, the pulse width of the magnetic field is considered to be longer than the pulse width of the energy beam, but in this case, the second
It is preferable to apply a pulse of an external magnetic field and control so that the pulse of the energy ray is applied where the magnetic field becomes maximum.

Magnetic recording media and AFCs with enhanced dynamic coercive force
Applying a pulsed magnetic field as the second external magnetic field to the medium is particularly effective. For example, a magnetic recording medium having two magnetic layers, which has a magnetic layer for recording and a stabilizing magnetic layer for maintaining thermal stability, may be mentioned. Since the stabilizing magnetic layer acts to suppress the instantaneous magnetization reversal of the recording magnetic layer, the dynamic coercive force is high and it is difficult to form a magnetization pattern by the conventional method. An excellent magnetic pattern can be formed by applying an external magnetic field in the vicinity of a static coercive force or higher to such a medium in pulses.

The second external magnetic field can form a plurality of magnetization patterns at once by applying the external magnetic field also over the heated wide area. When local heating can be performed on the entire surface of the magnetic recording medium at one time, it is desirable to apply a second external magnetic field to the entire surface of the medium at the same time as heating to form a magnetization pattern. Thereby, the magnetization pattern can be formed in a shorter time, and the cost can be greatly reduced. Further, in order to apply the magnetic field to only a part of the medium, it is often the case that the magnet arrangement is devised or specific measures are taken so that the magnetic field does not reach the other areas, but it is necessary to apply it to the entire surface. Absent. Moreover, since the rotating mechanism or the moving mechanism is not necessary, the device configuration is simple and the magnetic recording medium can be obtained at a low cost.

For example, if the medium is a disk-shaped magnetic recording medium having a small diameter of 2.5 inches or less, it is preferable that the entire surface of the disk can be irradiated with energy rays and a magnetic field can be applied by a simple arrangement or means. More preferably, the diameter is 1 inch or less. Further, when it is desired to apply a magnetic field to the disk-shaped magnetic recording medium in the circumferential direction, a large vertical pulse current can be passed through the center of the medium to easily generate a magnetic field in the circumferential direction. This is especially the diameter 1
It is preferably applied to a disk-shaped magnetic recording medium having a small diameter of not more than inch.

The present invention is suitable for forming a magnetization pattern having control information for controlling the recording / reproducing magnetic head. For example, it is a pattern for generating a signal corresponding to the position of the head. The control information is for controlling the recording / reproducing means such as a magnetic head using the information. For example, the servo information for positioning the magnetic head on the data track and the position of the magnetic head on the medium are determined. The address information indicates the synchronization information for controlling the recording / reproducing speed of the magnetic head. Alternatively, reference information for later writing servo information is also included.

These control magnetization patterns need to be formed with high precision. Particularly, since the servo pattern is a data track position control pattern, if the servo pattern accuracy is poor, the head position control will also be rough. However, a data pattern having a higher positional accuracy than the servo pattern cannot be theoretically recorded. Therefore, the higher the recording density of the medium, the more accurately the servo pattern needs to be formed.

In the present invention, since a highly accurate servo pattern or reference pattern can be obtained, the track density is particularly 40.
It is highly effective when applied to a magnetic recording medium for high density recording having a kTPI or more. Next, a method for locally heating the magnetic layer in the present invention will be described. The heating means is
It suffices if it has the function of heating the magnetic layer surface partially, but in consideration of prevention of heat diffusion to unnecessary portions and controllability, power control, energy of laser etc. that can easily control the size of the heated portion Use lines.

Here, by using the mask in combination, it is possible to irradiate the energy beam through the mask to form a plurality of magnetization patterns at once, so that the magnetization pattern forming step is short and simple. It is preferable that the energy beam is pulsed rather than continuous irradiation to control the heating site and control the heating temperature. The use of a pulsed laser light source is particularly preferable. A pulsed laser light source oscillates a laser in a pulsed manner intermittently, and compared with a continuous laser that is intermittently pulsed by an optical component such as an acousto-optic device (AO) or an electro-optic device (EO), It is possible to irradiate a laser having a high power peak value in a very short time, and it is very preferable that heat is hardly accumulated.

When a continuous laser is pulsed by optical components, it has almost the same power within the pulse width within the pulse. On the other hand, the pulsed laser light source accumulates energy by resonance in the light source, for example, and emits the laser as a pulse at a time. Therefore, the power of the peak is very large in the pulse and then becomes small. In the present invention, it is preferable to use rapid heating in a very short time and then rapid cooling in order to form a highly precise and highly accurate magnetization pattern. Therefore, the use of a pulsed laser light source is suitable.

It is preferable that the medium surface on which the magnetization pattern is formed has a large temperature difference between the irradiation of the pulsed energy beam and the non-irradiation thereof in order to increase the contrast of the pattern or increase the recording density. Therefore, it is preferable that the temperature is about room temperature or lower when the pulsed energy beam is not irradiated. Room temperature is about 25 ° C. When using the pulsed energy beam, the external magnetic field may be continuously applied or pulsed.

The wavelength of the energy rays 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 it is easy to form a fine magnetization pattern. More preferably, the wavelength is 600 nm or less. Not only the resolution is high, but also the diffraction is small, so that the spacing between the mask and the magnetic recording medium can be widely taken due to the gap, and the handling is easy, and the magnetization pattern forming device can be easily configured. The wavelength is 1
It is preferably 50 nm or more. If it is less than 150 nm, the absorption of synthetic quartz used for the mask becomes large, and heating tends to be insufficient. If the wavelength is 350 nm or more, the optical glass can be used as a mask.

Specifically, the excimer laser (157, 1
93, 248, 308, 351 nm), a YAG Q-switched laser (1064 nm) second harmonic (532 nm),
3rd harmonic (355nm) or 4th harmonic (266nm),
Examples thereof include Ar laser (488 nm, 514 nm) and ruby laser (694 nm). The power of energy rays is
The optimum value may be selected depending on the magnitude of the external magnetic field, but the power per pulse of the pulsed energy beam is 100.
It is preferably 0 mJ / cm ² or less. If a power larger than this is applied, the surface of the magnetic recording medium may be damaged and deformed by the pulsed energy rays. If the roughness Ra of the medium increases to 3 nm or more and the waviness Wa increases to 5 nm or more due to the deformation, the running of the flying / contact type head may be hindered.

It is more preferably 500 mJ / cm ² or less, still more preferably 200 mJ / cm ² or less.
In this region, it is easy to form a magnetization pattern with high resolution even when a substrate having a relatively large thermal diffusion is used. The power is preferably 10 mJ / cm ² or more. If it is smaller than this, the temperature of the magnetic layer is hard to rise and magnetic transfer is hard to occur. In addition, since the influence of the diffraction of the energy beam changes depending on the pattern width, the optimum power also changes according to the pattern width. Also, the shorter the wavelength of the energy rays, the lower the upper limit of the power that can be applied tends to decrease.

When the magnetic layer, the protective layer, and the lubricating layer may be damaged by the energy rays, the power of the pulsed energy rays is reduced to increase the strength of the magnetic field applied simultaneously with the pulsed energy rays. You can also take such means. In addition, when irradiating the pulsed energy beam through the protective layer and the lubricating layer, it may be necessary to re-apply after irradiation in consideration of damage (decomposition, polymerization) to the lubricant.

The pulse width of the pulsed energy beam is 1 μm.
It is desirable that it is sec or less. If the pulse width is wider than this, the heat generated by the energy applied to the magnetic recording medium is dispersed, and the resolution is likely to decrease. When the power per pulse is the same, when the pulse width is shortened and strong energy is applied at one time, thermal diffusion tends to be small and the resolution of the magnetization pattern tends to be high. More preferably 100 nsec
It is the following. In this region, it is easy to form a magnetization pattern with high resolution even when a substrate such as Al having a relatively large thermal diffusion is used. When forming a pattern having a minimum width of 2 μm or less, the pulse width is preferably 25 nsec or less. That is, if the resolution is important, the shorter the pulse width, the better. The pulse width is preferably 1 nsec or more. This is because it is preferable to keep heating for the time until the magnetization reversal of the magnetic layer is completed.

In the present invention, the minimum width of the pattern means the narrowest length in the pattern. A square pattern has a short side, a circle has a diameter, and an ellipse has a short diameter. As a kind of pulsed laser, there is a laser capable of generating an ultrashort pulse of picosecond or femtosecond level at a high frequency like a mode-locked laser. During the period of irradiating the ultra-short pulse with a high frequency, the laser is not emitted for a very short time between the ultra-short pulses, but the heating portion is hardly cooled because it is a very short time. For example, a region once heated to 200 ° C. is maintained at about 200 ° C.

Therefore, in such a case, one pulse is set as the continuous irradiation period (the continuous irradiation period including the time during which the laser is not irradiated during the ultrashort pulse). In addition, the integrated value of the irradiation energy amount during the continuous irradiation period is calculated as the power per pulse (mJ /
cm ² ). In addition, energy rays such as laser,
Generally, the beam spot has an intensity distribution (energy density distribution), and a difference in temperature rise due to the energy density also occurs when local heating is performed by irradiating energy beams. Therefore, the unevenness of heating causes a local difference in transfer strength. Therefore, it is preferable that the energy rays are previously subjected to a uniform intensity distribution treatment. The distribution of the heating state of the irradiated region can be suppressed to a small value, and the distribution of the magnetic strength of the magnetization pattern can be suppressed to a small value. Therefore, when the signal intensity is read using the magnetic head, it is possible to form a magnetization pattern having high uniformity of the signal intensity.

Examples of the intensity distribution homogenizing process include the following processes. The homogenizer or condenser lens is used for homogenization, and a light-shielding plate, slit, or the like is used to transmit only a portion having a small intensity distribution of energy rays and enlarge it as necessary. The mask of the present invention is
This is a so-called photomask that has a transmission part and a non-transmission part of the energy ray, and changes the intensity distribution of the energy ray according to the magnetization pattern to be formed, and forms the intensity of the energy ray (intensity distribution) on the magnetic disk surface. To do. Thereby, a plurality of or a wide area of the magnetic pattern can be formed at one time, and the magnetic pattern forming process can be simplified in a short time.

The mask does not have to cover the entire surface of the magnetic disk. If there is a size including a repeating unit of the magnetization pattern, it can be moved and used. Although the material of the mask is not limited, it is preferable that the mask is made of a non-magnetic material in the present invention because a magnetized pattern can be formed in any pattern shape with uniform clarity and a uniform and strong reproduction signal can be obtained.

When a mask containing a ferromagnetic material is used,
The magnetic field may be disturbed by the magnetization. Due to the nature of ferromagnetism,
In the case of the radial direction of the magnetic disk or the pattern shape inclined from the arcuate pattern extending in the radial direction, the magnetic domains do not sufficiently oppose each other at the magnetization transition portion, and thus it is difficult to obtain a good signal. The mask is arranged between the light source of energy rays and the magnetic recording medium. If importance is placed on the accuracy of the magnetization pattern, it is preferable to bring all or part of the mask into contact with the medium. The influence of laser light diffraction can be minimized, and a magnetization pattern with high resolution can be formed. For example, when the mask is allowed to stand on the medium, undulations of several .mu.m on the surface of the medium may cause a portion that contacts the medium and a portion that does not contact the medium. However, the pressure applied to the mask and the medium is 100 g / cm ² so that the medium is not indented or damaged.
Below.

However, in order to reduce defects and scratches,
It is preferable to provide a gap between the mask and the medium at least in the region where the magnetization pattern of the medium is formed. It is possible to suppress scratches on the medium and the mask due to entrapment of dust and the like and generation of defects. Further, when the lubricating layer is provided before the formation of the magnetization pattern, it is particularly preferable to provide a gap between the mask and the medium. This is to minimize the adhesion of lubricant to the mask. Also, when a mask with a disk provided with a lubricating layer is contacted with a high-power energy beam, a rapid vaporization of the lubricant causes an explosive state, causing the lubricant to scatter or even damage the mask. This is because there is a risk of

As a method for maintaining the gap between the magnetic pattern forming region of the magnetic recording medium and the mask, any method may be used so long as the two can be kept 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 in a place other than the magnetic pattern forming region. A spacer may be integrally formed on the mask itself.

If a spacer is provided between the mask and the magnetic recording medium at the outer peripheral portion and / or the inner peripheral portion of the magnetic pattern forming region of the medium, an effect of correcting the waviness of the surface of the magnetic recording medium is produced, so that the magnetic pattern is formed. It is good because the accuracy increases. The spacer material is preferably hard. Further, since an external magnetic field is used for pattern formation, it is preferable that the pattern is not magnetized. Preferred are metals such as stainless steel and copper, and resins such as polyimide. Height is arbitrary, but usually several μ
m to several hundreds of μm.

The minimum gap between the mask and the magnetic recording medium is 0.1.
It is preferably μm or more, which can suppress damage and defect generation of the magnetic recording medium and the mask due to entrapment of dust and the like. That is, by setting the interval to 0.1 μm or more, it is possible to prevent the magnetized pattern forming portion from unexpectedly contacting the mask due to the waviness of the medium surface. Therefore, since the thermal conductivity of the medium changes at the contact portion, the susceptibility to magnetization changes specifically, and there is no problem that the magnetization pattern is not formed according to the desired pattern. More preferably, it is 0.2 μm or more. However, the interval is preferably 1 mm or less. As a result, there is no problem that the diffraction of energy rays is small and the magnetization pattern is blurred.

For example, by using an excimer laser (248 nm), a 2 × 2 μm pattern (2 μm) formed on the mask is formed.
pattern having alternating transparent portions of m and non-transparent portions of 2 μm)
In the case of transferring to the medium, it is necessary to keep the distance between the mask and the medium to about 25 to 45 μm or less. If the distance is larger than this, the bright and dark pattern of the laser light becomes unclear due to the diffraction phenomenon. 1 × 1μm pattern (1μm
In the case of a pattern having alternating transparent portions and non-transparent portions of 1 μm), the distance is about 10 to 15 μm or less.

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

A magnetic disk may have magnetic layers formed on both main surfaces of the disk. In this case, the magnetic pattern formation of the present invention may be carried out sequentially on each side, or a mask, an energy irradiation system and It is also possible to install means for applying an external magnetic field on both sides of the magnetic disk to form the magnetization pattern on both sides simultaneously. When two or more magnetic layers are formed on one surface and you want to form different patterns for each, you can individually heat each layer by focusing the energy beam to irradiate each layer and form an individual pattern. .

When forming the magnetization pattern, a light-shielding plate capable of partially shielding the energy rays between the light source of the energy rays and the mask or the area between the mask and the medium where irradiation is not desired. Is preferably provided to prevent re-irradiation of energy rays. The light shielding plate may be one that does not transmit the wavelength of the energy rays used, and may reflect or absorb the energy rays. However, it is preferable to use a material having a high thermal conductivity and a high reflectance, since it absorbs energy rays and is likely to be heated and affect the magnetization pattern.
For example, it is a metal plate of Cr, Al, Fe or the like.

Further, preferably, a reduction imaging technology (imaging optical system) is used for the optical system. A patterned energy ray having an intensity distribution according to the magnetization pattern to be formed is reduced and imaged on the medium surface. According to this, the accuracy of the magnetization pattern is not limited by the patterning accuracy and the alignment accuracy of the mask, as compared with the case of passing the energy beam through the mask after narrowing it down with the objective lens, that is, the case of proximity exposure. It is possible to accurately form a fine magnetization pattern. Further, since the mask and the medium are separated from each other, dust on the medium is less likely to be affected.

According to the present technique, the energy ray emitted from the light source is changed in intensity distribution through the mask, and reduced and imaged on the medium surface through the image forming means such as the image forming lens. The imaging lens may be referred to as a projection lens, and the reduced image may be referred to as reduced projection. Next, the structure of the magnetic recording medium of the present invention will be described.

As the substrate in the magnetic recording medium according to the present invention, it is necessary that it does not vibrate even when rotated at high speed during high-speed recording / reproduction, and a hard substrate is usually used. In order to obtain sufficient rigidity without vibration, the substrate thickness is generally preferably 0.3 mm or more. However, if the thickness is thick, it is disadvantageous in reducing the thickness of the magnetic recording device. For example, an Al alloy substrate containing Al as a main component, such as an Al-Mg alloy, or Mg
A Mg alloy substrate containing, for example, Mg-Zn alloy, a soda glass, an aluminosilicate glass, an amorphous glass, a substrate made of any of silicon, titanium, ceramics, and various resins, or a combination thereof. A substrate or the like can be used. Above all, it is preferable to use an Al alloy substrate, a glass substrate such as crystallized glass in terms of strength, and a resin substrate in terms of cost.

The present invention is highly effective when applied to a medium having a hard substrate. In the conventional magnetic transfer method, a medium having a hard substrate tends to have insufficient adhesion to a master (master disk) to cause scratches or defects, and the boundaries of the transferred magnetic domains are unclear, so that the PW50 tends to spread. However, in the present invention, since the mask and the medium are not pressure-bonded, there is no such problem. In particular, it is effective for a medium having a substrate that easily cracks such as a glass substrate.

In the manufacturing process of the magnetic recording medium, the substrate is usually washed and dried first, and in the present invention as well, from the viewpoint of ensuring the adhesiveness of each layer, the substrate is washed and dried before its formation. Is desirable. When manufacturing the magnetic recording medium of the present invention, a metal layer such as NiP or NiAl may be formed on the surface of the substrate.

When the metal layer is formed, the method includes electroless plating, sputtering, vacuum deposition,
A method used for forming a thin film such as a CVD method can be used. If the substrate is made of a conductive material, electrolytic plating can be used. The thickness of the metal layer is preferably 50 nm or more. However, it is preferably 20 μm or less in consideration of the productivity of the magnetic recording medium. More preferably, it is 10 μm or less.

Further, it is desirable that the region where the metal layer is formed is all over the surface of the substrate, but it is also possible to carry out only a part, for example, only the region to which texturing is applied. Further, concentric texturing may be applied to the surface of the substrate or the surface of the substrate on which the metal layer is formed. Concentric textured in the present invention, for example, mechanical texturing using free abrasive grains and texture tape or texturing using a laser beam, or by using them in combination, by polishing in the circumferential direction, The state in which a large number of minute grooves are formed in the circumferential direction of the substrate is referred to.

Generally, mechanical texturing is performed in order to obtain in-plane anisotropy of the magnetic layer. If it is desired to form an in-plane isotropic magnetic layer, this is not necessary. Further, generally, texturing using a laser beam or the like is performed in order to improve CSS (contact start and stop) characteristics. This need not be applied in the case where the magnetic recording device is of a system (load / unload system) in which the head is retracted outside the magnetic recording medium when not driven.

Alumina abrasive grains are widely used as the abrasive grains used for mechanical texturing. From the viewpoint of the in-plane orientation medium in which the easy axis of magnetization is oriented along the texturing groove, the diamond abrasive grain is used. The granules show extremely good performance. Among them, the one whose surface is graphitized is most preferable. It is effective for realizing high-density magnetic recording that the head flying height is as small as possible, and one of the features of these substrates is excellent surface smoothness. Therefore, the substrate surface roughness Ra is preferably 2 nm or less, More preferably, it is 1 nm or less. Particularly, 0.5 nm or less is preferable. The substrate surface roughness Ra
Is a value calculated according to JIS B0601 after measurement with a stylus type surface roughness meter at a measurement length of 400 μm. 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 on the substrate between it and the magnetic layer. The underlayer is preferably made of Cr as a main component for the purpose of refining the crystal and controlling the orientation of the crystal plane. As the material of the underlayer containing Cr as a main component, in addition to pure Cr, V, Ti, Mo, Z may be added to Cr for the purpose of crystal matching with the recording layer.
Alloys and Cr oxides containing one or more elements selected from r, Hf, Ta, W, Ge, Nb, Si, Cu and B
And so on.

Above all, pure Cr or Cr, Ti, Mo,
An alloy added with one or more elements selected from W, V, Ta, Si, Nb, Zr and Hf is preferable. Although the optimum amount of these second and third elements varies depending on the respective elements, it is generally preferably 1 atom% to 50 atom%, more preferably 5 atom% to 30 atom%, and further preferably 5 atom%. % To 20 atom%.

The thickness of the underlayer may be any thickness sufficient to exhibit this anisotropy, but is preferably 0.1 to 50.
nm, more preferably 0.3 to 30 nm, still more preferably 0.5 to 10 nm. The substrate may or may not be heated when the underlayer containing Cr as a main component is formed. A soft magnetic layer may be provided on the underlayer between the recording layer and the recording layer. In particular, it is suitable for use in a keeper medium with little magnetization transition noise or a perpendicular recording medium in which magnetic domains are perpendicular to the in-plane of the medium.

The soft magnetic layer may have a relatively high magnetic permeability and a small loss, but NiFe or an alloy in which Mo or the like is added as the third element is preferably used. The optimum magnetic permeability varies greatly depending on the characteristics of the head and recording layer used for recording data, but it is generally preferable that the maximum magnetic permeability is about 10 to 1,000,000 (H / m).

Alternatively, if necessary, an intermediate layer may be provided on the underlayer containing Cr as a main component. For example, it is preferable to provide a CoCr-based intermediate layer because the crystal orientation of the magnetic layer can be easily controlled. Next, a recording layer (magnetic layer) is formed. A layer made of the same material as the underlayer or another non-magnetic material may be inserted between the recording layer and the soft magnetic layer. The substrate may or may not be heated during the formation of the recording layer.

As the recording layer, a Co alloy magnetic layer, TbF
A rare earth-based magnetic layer typified by eCo, a transition metal / noble metal-based laminated film typified by a laminated film of Co and Pd, and the like are preferably used. The Co alloy magnetic layer is usually pure Co.
Or CoNi, CoSm, CoCrTa, CoNiCr,
C which is generally used as a magnetic material such as CoCrPt
o Alloy magnetic materials can be used. In addition to these Co alloys, N
It is also possible to add elements such as i, Cr, Pt, Ta, W and B or compounds such as SiO ₂ . For example CoCrPtT
a, CoCrPtB, CoNiPt, CoNiCrPt
B etc. are mentioned. The thickness of the Co alloy magnetic layer is arbitrary, but is preferably 5 nm or more, more preferably 10 nm or more. Further, it is preferably 50 nm or less, more preferably 30 nm or less. Further, the present recording layer may be directly laminated with two or more layers via a suitable non-magnetic intermediate layer. At that time, the compositions of the magnetic materials to be laminated may be the same or different.

As the rare earth magnetic layer, a general magnetic material can be used. For example, TbFeCo or Gd.
FeCo, DyFeCo, TbFe, etc. are mentioned.
You may add Tb, Dy, Ho, etc. to these rare earth alloys. Ti, Al, and Pt may be added for the purpose of preventing oxidative deterioration. The thickness of the rare earth magnetic layer is arbitrary, but is usually about 5 to 100 nm. Further, the present recording layer may be directly laminated with two or more layers via a suitable non-magnetic intermediate layer. At that time, the compositions of the magnetic materials to be laminated may be the same or different. In particular, the rare-earth magnetic layer is an amorphous structure film and has magnetization in the direction perpendicular to the medium surface. Therefore, the rare-earth magnetic layer is suitable for high-density recording, and the method of the present invention is capable of forming a high-density and highly-accurate magnetization pattern. It can be applied more effectively.

Similarly, as a laminated film of a transition metal and a noble metal, which can perform perpendicular magnetic recording, a general magnetic material can be used. For example, Co / Pd, Co / Pt, Fe.
/ Pt, Fe / Au, Fe / Ag, etc. are mentioned. The transition metal and the noble metal of these laminated film materials may not be particularly pure, and may be an alloy mainly of them. The film thickness of the laminated film is arbitrary, but is usually 5 to 1000.
It is about nm. Further, it may be a laminate of three or more kinds of materials, if necessary.

Recently, an AFC (Anti-Ferromagnetic coupled) medium has been proposed in order to enhance the thermal stability of magnetic domains. Two or more magnetic layers (main magnetic layer and subbing magnetic layer) are laminated through a Ru layer of several angstroms, etc., and magnetic coupling is performed above and below the Ru layer to improve the thermal stability of the main magnetic layer. It is an enhanced medium. This medium has a large apparent coercive force, and a large magnetic field is required for reversing the magnetization.

In the present invention, it is preferable that the recording layer is thin. This is because if the recording layer is thick, the heat transfer in the film thickness direction is poor when the recording layer is heated, and there is a possibility that the recording layer will not be magnetized well. Therefore, the thickness of the recording layer is preferably 200 nm or less. However, in order to maintain the magnetization, the film thickness of the recording layer is preferably 5 nm or more. In the present invention, the magnetic layer as the recording layer retains its magnetization at room temperature and is demagnetized by being applied with an external magnetic field at the same time as it is heated or magnetized in the opposite direction.

Coercive force of magnetic layer at room temperature (static coercive force)
Must retain its magnetization at room temperature and be uniformly magnetized by an appropriate external magnetic field. By setting the coercive force of the magnetic layer at room temperature to 2000 Oe or more, a small magnetic domain can be retained and a medium suitable for high density recording can be obtained.
More preferably, it is 3000 Oe or more. In the conventional magnetic transfer method, it was difficult to transfer to a medium having a very high coercive force, but in the present invention, since the magnetic layer is heated and the coercive force is sufficiently lowered to form the magnetization pattern, the coercive force is large. Application to media is preferred.

However, it is preferably 20 kOe or less. If it exceeds 20 kOe, a large external magnetic field is required for collective magnetization, and normal magnetic recording may be difficult. It is more preferably 15 kOe or less, and further preferably 10 kOe or less. The coercive force of the magnetic layer, the local heating temperature, and the second external magnetic field strength will be described.
For example, in a medium having a coercive force of 3500 to 4000 Oe at room temperature, the coercive force generally linearly decreases at a rate of 10 to 15 Oe / ° C as the temperature rises.
It will be about 0 Oe. If it is about 3000 Oe, it can be easily generated by the external magnetic field applying means.
A sufficient magnetization pattern can be formed even by heating at about ° C.

The dynamic coercive force of the magnetic layer is large in order to stably hold information recorded at high density. The dynamic coercive force is usually the coercive force measured when the magnetic field strength is changed in a short time of 1 sec or less, that is, the coercive force for a magnetic field having a pulse width of 1 sec or less. However, the value changes depending on the magnetic field and heat application time. Preferably, the dynamic coercive force at 1 sec is twice or more the static coercive force. However, if it is too large, a large magnetic field strength is required for magnetization by the second external magnetic field, so 20 kOe or less is preferable.

An example of the procedure for measuring the dynamic coercive force of the magnetic recording medium (coercive force of the magnetic layer as the recording layer) will be shown below. 1. The coercive force of the medium at the application time t = 10 sec is calculated. 1.1 Saturate the medium by applying a magnetic field up to the maximum magnetic field strength (20 kOe).

1.2 Negative direction (opposite to saturation direction)
A magnetic field H1 of a predetermined intensity is applied to the. 1.3 Hold for 10 seconds under the magnetic field. 1.4 Return the magnetic field to zero. The residual magnetization value M1 is obtained by reading the magnetization value at 1.5 1.4.

The same measurement (1.1 to 1.5) is repeated with the applied magnetic field strength slightly changed from 1.6 to 1.2. Remanent magnetization value M at magnetic field strengths H1, H2, H3, H4 at four points in total
1, M2, M3, M4 are obtained. 1.7 From these four points, the applied magnetic field strength H at which the residual magnetization M becomes 0 is obtained. This is the coercive force of the medium at the application time t = 10 sec.

2. Application time t is 60sec, 100se
The same measurement is performed for c and 600 seconds, and the coercive force at each application time is obtained. 3. 10 sec, 60 sec, 100 s obtained above
By extrapolating from the value of coercive force at ec, 600 sec, the coercive force in a shorter application time can be obtained.

For example, the dynamic coercive force at the application time of 1 nsec can also be obtained. The magnetic layer needs to be magnetized by a weak external magnetic field at an appropriate heating temperature while maintaining the magnetization at room temperature. Further, the larger the difference between the room temperature and the magnetization disappearance temperature, the easier it is for the magnetic domains of the magnetization pattern to be formed clearly. Therefore, the magnetization disappearance temperature is preferably high, preferably 100 ° C. or higher, more preferably 150 ° C. or higher. For example, the magnetization disappearance temperature is near the Curie temperature (slightly below the Curie temperature) or near the compensation temperature.

The Curie temperature is preferably 100 ° C. or higher. If it is less than 100 ° C, the stability of magnetic domains at room temperature tends to be low. It is more preferably 150 ° C. or higher. Further, it is preferably 700 ° C. or lower. This is because if the magnetic layer is heated to too high a temperature, it may be deformed. In the present invention, the AFC (Anti-Ferromagne
The Curie temperature of a tic coupled medium is not the Curie temperature of the main magnetic layer but the apparent Curie temperature of the entire medium.

When the magnetic recording medium is an in-plane magnetic recording medium, it is difficult to perform saturation recording by a conventional magnetic transfer method on a magnetic recording medium having a high coercive force for high density, and a magnetic pattern having a high magnetic field strength is obtained. It becomes difficult to generate, and the half-width also widens. Even in an in-plane recording medium suitable for such a high recording density, the present method enables good magnetization pattern formation. In particular, when the saturation magnetization of the magnetic layer is 50 emu / cc or more, the effect of the demagnetizing field is large and the effect of applying the present invention is great.

If it is 100 emu / cc or more, the effect is higher. However, if it is too large, it is difficult to form a magnetized pattern, so 500 emu / cc or less is preferable. When the magnetic recording medium is a perpendicular magnetic recording medium and the magnetization pattern is relatively large and the unit volume of one magnetic domain is large, the saturation magnetization becomes large and the magnetization reversal easily occurs due to the magnetic demagnetization action, which causes noise. Worsen the half-width. But,
In the present invention, good recording is possible on these media by using the underlayer which uses soft magnetism in combination.

Two or more recording layers may be provided to increase the recording capacity. At this time, it is preferable to interpose another layer between them. In the present invention, it is preferable to form a protective layer on the magnetic layer. That is, the outermost surface of the medium is covered with a hard protective layer. The protective layer serves to prevent the magnetic layer from being damaged by being caught in the head, a collision, or a mask such as dust or dust. When applying the magnetic pattern forming method using a mask as in the present invention, it also has a function of protecting the medium from contact with the mask.

In the present invention, the protective layer also has an effect of preventing the heated magnetic layer from being oxidized. The magnetic layer is generally easily oxidized, and further easily oxidized when heated. In the present invention, since the magnetic layer is locally heated by energy rays or the like, it is desirable to previously form a protective layer for preventing oxidation on the magnetic layer. When there are a plurality of magnetic layers, the protective layer may be provided on the magnetic layer close to the outermost surface. The protective layer may be provided directly on the magnetic layer, or may be provided with a layer having another function therebetween, if necessary.

Part of the energy rays are absorbed by the protective layer, and serve to locally heat the magnetic layer by heat conduction. Therefore, if the protective layer is too thick, the magnetization pattern may be blurred due to heat conduction in the lateral direction. Therefore, it is preferable that the film thickness is thin. Further, it is preferable that the thickness is thin in order to reduce the distance between the magnetic layer and the head during recording and reproduction. Therefore, it is preferably 50 nm or less, more preferably 30 nm.
Or less, more preferably 20 nm or less. However,
In order to obtain sufficient durability, the thickness is preferably 0.1 nm or more, more preferably 1 nm or more.

The protective layer may be hard and resistant to oxidation. Generally carbon, hydrogenated carbon,
Nitrogenated carbon, amorphous carbon, carbonaceous layers such as SiC, SiO ₂ , Zr ₂ O ₃ , SiN, TiN, etc. are used. The protective layer may be a magnetic material.
Particularly, in order to make the distance between the head and the magnetic layer as close as possible, it is preferable to provide a very hard protective layer thinly.
Therefore, in terms of impact resistance and lubricity, a carbonaceous protective film is preferable, and diamond-like carbon is particularly preferable. Not only does it play a role of preventing damage to the magnetic layer due to energy rays, but it also becomes extremely strong against damage to the magnetic layer by the head.
The magnetization pattern forming method of the present invention can be applied to an opaque protective layer such as a carbonaceous protective layer.

The protective layer may be composed of two or more layers. It is preferable to provide a layer containing Cr as a main component immediately above the magnetic layer because the effect of preventing oxygen permeation into the magnetic layer is high. Further, it is preferable to form a lubricating layer on the protective layer. It has the function of preventing damage from the media mask and magnetic head. Examples of the lubricant used in the lubricating layer include fluorine-based lubricants, hydrocarbon-based lubricants and mixtures thereof, which can be applied by a conventional method such as a dipping method or a spin coating method. You may form into a film by a vapor deposition method. The lubricating layer is preferably thin so that it does not hinder the formation of the magnetization pattern, and is preferably 10 nm or less. More preferably 4n
m or less. 0.5n to obtain sufficient lubrication performance
m or more is preferable. More preferably, it is 1 nm or more.

In the case of irradiating the energy beam from above the lubricating layer, recoating may be performed in consideration of damage (decomposition, polymerization) of the lubricant and the like. Further, other layers may be added to the above layer structure as needed. In order not to impair the running stability of the flying / contact type head, it is preferable to keep the surface roughness Ra of the medium after the formation of the magnetic pattern at 3 nm or less. The medium surface roughness Ra is the roughness of the medium surface that does not include a lubricating layer, and is a stylus surface roughness meter (model name: Tenc
or P-12 disk profiler (manufactured by KLA Tencor) with a measurement length of 400 μm, and then calculated according to JIS B0601. It is more preferably 1.5 nm or less.

Desirably, the surface waviness Wa of the medium after the formation of the magnetization pattern is kept at 5 nm or less. Wa is the waviness of the medium surface that does not include a lubricating layer, and is measured with a stylus surface roughness meter (model name: Tencor P-12 disk profiler (KLA Tencor)) at a measurement length of 2 mm, and then Ra It is a value calculated according to the calculation. It is more preferably 3 nm or less.

By the way, the formation of the magnetization pattern on the magnetic recording medium having such a structure is performed on the recording layer (magnetic layer). It is preferable to carry out by any of the methods described after forming a protective layer, a lubricating layer, etc. on the recording layer, but if there is no risk of oxidation of the recording layer, it may be carried out immediately after the recording layer is formed. Although various methods can be adopted as a film forming method for forming each layer of the magnetic recording medium, for example, a physical vapor deposition method such as a direct current (magnetron) sputtering method, a high frequency (magnetron) sputtering method, an ECR sputtering method, or a vacuum evaporation method is used. Can be mentioned.

As the conditions for film formation, the ultimate vacuum, the substrate heating method and substrate temperature, the sputtering gas pressure, the bias voltage, etc. are appropriately determined according to the characteristics of the medium to be obtained. For example, in sputtering film formation, the ultimate vacuum is usually 5 × 10 ⁻⁶ Torr or less, the substrate temperature is room temperature to 400 ° C., and the sputtering gas pressure is 1 × 10 ⁻³ to.
20 × 10 ^-3 Torr, bias voltage is 0 to -500V
Is preferred.

When the substrate is heated, it may be heated before the base layer is formed. Alternatively, when a transparent substrate having a low heat absorption rate is used, in order to increase the heat absorption rate, a seed layer containing Cr as a main component or a base layer having a B2 crystal structure is formed and then the substrate is heated. After that, a recording layer or the like may be formed. When the recording layer is a rare earth magnetic layer, from the viewpoint of corrosion / oxidation prevention, the innermost and outermost portions of the disk-shaped magnetic recording medium are first masked to form a film up to the recording layer,
During the subsequent formation of the protective layer, the mask is removed to completely cover the recording layer with the protective layer, or when the protective layer has two layers, the recording layer and the first protective layer are masked. Then, the mask is removed when the second protective layer is formed, and the recording layer is also changed to the second layer.
It is preferable to completely cover the protective layer with the above because the corrosion and oxidation of the rare earth magnetic layer can be prevented.

Next, the magnetic recording apparatus of the present invention will be described. A magnetic recording apparatus according to the present invention includes a magnetic recording medium having a magnetization pattern formed by the above-described method, a drive 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 head. It has means for moving it relative to the 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. As the magnetic head, a flying / contact type magnetic head is usually used for high density recording.

By using a magnetic recording medium on which a fine and highly precise magnetized pattern such as a servo pattern is formed by the method of the present invention, the magnetic recording apparatus can perform high density recording. Further, since the medium has no scratches and few defects, recording with few errors can be performed. In addition, after incorporating the magnetic recording medium into the device, the above-mentioned magnetization pattern is reproduced by a magnetic head to obtain a signal, and a servo burst signal is recorded by the magnetic head using the signal as a reference. It is possible to easily obtain a precise servo signal.

Further, even after the servo burst signal is recorded by the magnetic head, if the signal recorded as the magnetization pattern according to the present invention remains in the area not used as the user data area, the magnetic head is displaced due to some disturbance. Since it is easy to return to the desired position even when the magnetic recording device has a signal by both writing methods,
Highly reliable.

A magnetic disk device, which is a typical magnetic recording device, will be described as an example. A magnetic disk device usually includes a shaft for fixing one or more magnetic disks in a skewered shape, a motor for rotating the magnetic disk joined to the shaft through a bearing, and a magnetic disk used for recording and / or reproducing. The head includes 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 by the flying height. The recording information is converted into a recording signal through the signal processing means and recorded by the 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 disc, information signals are recorded in sector units along concentric tracks. Servo patterns are typically recorded between sectors. The magnetic head reads the servo signal from the pattern, thereby accurately tracks the center of the track, and reads the information signal of the sector. The same tracking is performed during recording.

As described above, the servo pattern for generating the servo signal is required to have a particularly high precision because of the property of being used for tracking when recording information. Further, since the servo pattern that is often used at present is composed of two sets of patterns which are displaced from each other by ½ pitch per track, it is necessary to form the servo pattern at every ½ pitch of the information signal, and the double precision is required. 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 in the center of gravity between the external pin and the actuator.
The limit is about 0.3 μm, and the accuracy of the servo pattern cannot keep up with the increase in track density, which is becoming an obstacle to improving the recording density and reducing the cost of the magnetic recording device. According to the present invention, since it is possible to efficiently form a highly accurate magnetization pattern, it is possible to form a servo pattern with high precision in a short time at a significantly lower cost as compared with a conventional servo pattern forming method. The track density of the medium can be increased. Therefore, the magnetic recording device using this medium can record at high density.

Further, when the phase servo method is used, a continuously varying servo signal can be obtained, so that the track density can be further increased, and tracking within a width of 0.1 μm or less is possible, and higher density recording is possible. is there. As mentioned above, in the phase servo system, for example, from the inner circumference to the outer circumference,
A magnetization pattern is used that extends linearly at an angle to the radius. Such a pattern continuous in the radial direction or an oblique pattern is difficult to form by the conventional servo pattern forming method in which the servo signal is recorded for each track while rotating the disk, and complicated calculation and configuration are required.

However, according to the present invention, once the mask corresponding to the shape is formed, the pattern can be easily formed by only irradiating the energy beam through the mask.
It is possible to easily and inexpensively produce a medium used for the phase servo method in a short time. 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 medium is incorporated into a magnetic recording device (drive) and then a dedicated servo writer is used in a clean room.

Each drive is mounted on a servo writer, and a pin of the servo writer is inserted through a hole on either the front surface or the back surface of the drive, and the magnetic head is mechanically moved to record one pattern at a time along a track.
Therefore, it takes a very long time of about 15 to 20 minutes per drive. It is necessary to perform these operations in a clean room because a dedicated servo writer is used and holes are formed in the drive, which is a complicated process and a cost factor.

According to the present invention, the servo pattern or the reference pattern for recording the servo pattern can be collectively recorded by irradiating the energy beam through the mask in which the pattern is recorded in advance. A pattern can be formed. The magnetic recording device incorporating the medium on which the servo pattern is formed in this manner does not require the servo pattern writing step.

Alternatively, a magnetic recording apparatus incorporating a medium on which a servo pattern recording reference pattern is formed can write a desired servo pattern in the apparatus based on the reference pattern, and the above servo writer is unnecessary. And
No work is required in a clean room. Further, it is not necessary to make a hole on the back side of the magnetic recording device, which is preferable in terms of durability and safety.

Further, in the present invention, since the mask and the medium do not have to be in close contact with each other, the damage due to the contact between the magnetic recording medium and the other constituent members and the damage due to the inclusion of minute dust or dust may occur. It can prevent the occurrence of defects. As described above, according to the present invention, a magnetic recording device capable of high-density recording can be obtained at a low cost through simple steps.

As the magnetic head, various types such as a thin film head, an MR head, a GMR head and a TMR head can be used. By configuring the reproducing unit of the magnetic head with the MR head, sufficient signal strength can be obtained even at high recording density, and a magnetic recording device with higher recording density can be realized. If the flying height of the magnetic head is as low as 0.001 μm or more and less than 0.05 μm, the output is improved and a high device S / N is obtained, and a large capacity and highly reliable magnetic recording is achieved. A 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 13 kTPI or more and the linear recording density is 250 kFCI.
As described above, sufficient S / N can be obtained even when recording / reproducing at a recording density of 3 Gbits per square inch or more. Further, in the reproducing portion of the magnetic head, a plurality of conductive magnetic layers that cause a large resistance change due to the mutual change of the magnetization directions by an external magnetic field, and a conductive non-magnetic layer disposed between the conductive magnetic layers. The signal strength can be further increased by using a GMR head composed of a magnetic layer or a GMR head utilizing the spin valve effect, and reliability with a linear recording density of 10 Gbits per square inch or more and 350 kFCI or more. It is possible to realize a high-performance magnetic recording device.

[0161]

EXAMPLES Examples of the present invention will be described below. However, the present invention is not limited to these examples unless the scope of the gist thereof is exceeded. (Example) First, a 127 mm × 127 mm square,
The substrate is made of quartz glass with a thickness of 2.3 mm, and the film thickness is 10
nm chromium layer and a photoresist layer having a film thickness of 20 nm were sequentially formed by spin coating. After that, exposure and development were performed to form an uneven pattern on the photoresist layer. Next, the chromium layer in the portion where the photoresist layer was removed was etched and removed by an etching solution for chromium containing cerium nitrate. Further, the photoresist layer was removed using acetone.

Next, using Plasmalab 80Plus manufactured by Oxford Instruments,
Reactive ion etching (RIE) was performed according to the following procedure. First, in order to remove organic deposits such as residual photoresist, etching with N ₂ O was performed for 2 minutes. The operating conditions are as follows: N ₂ O flow rate 100 sccm (25
Flow rate of 100 cc / min in terms of 1 atm), pressure 12.
5mTorr, RF output 100W, RF frequency 13.5
6 MHz. Then, the quartz glass was etched for 12 minutes using SF ₆ gas. The etching conditions are
SF ₆ flow rate 100sccm, pressure 30mTorr, RF
The output is 100W. After the RIE is completed, the chromium layer is removed using an etching solution for chromium, and a groove (recess) having a depth of 200 nm is formed in the pattern region on the surface side of the magnetic disk.
Thus, a quartz glass substrate on which was formed was obtained.

The depth of the groove (recess) was measured by AFM (atomic force microscope). More specifically, with Digital Instruments NanoScope IIIa D3100 manufactured by Digital Instruments, observation mode: tapping AFM, scan size:
The measurement was performed under the conditions of 10 μm and scan speed: 0.5 Hz. A standard needle was used for the device.

Then, Al is filled in the groove by a lift-off method.
A layer was formed to a thickness of 150 nm, and a mask was obtained in which the groove portion in which the Al layer was embedded was used as a non-transmissive portion and the other portions were used as a transmissive portion.
A pattern area having a radius of 20 to 46 mm and a pattern minimum line width of 0.7 μm (minimum width 0.7 μm; both line and space 0.7 μm) was provided. The minimum line width of the pattern at the innermost circumference is 0.7 μm, and the minimum line width of the pattern at the outermost circumference is about 1.2 μm.

The lift-off method was performed according to the following procedure. Photoresist is applied to a mask on which a pattern is formed in advance, and a separately prepared light-shielding member having a predetermined pattern is brought into close contact therewith. Then, the photoresist is exposed to light according to the pattern shape by irradiating ultraviolet rays through the light shielding member. After that, by developing,
A photoresist layer having recesses formed in the pattern formation portion is formed on the mask. An Al film having a thickness of 150 nm is formed thereon by a sputtering method or a vacuum evaporation method. A
The l-layer adheres to the recess of the quartz substrate and the photoresist layer, but by removing the photoresist layer with acetone or the like, the Al layer on the photoresist is also removed, and the Al layer remains only in the recess.

Thereafter, a spacer made of a Cr layer was provided again on the peripheral portion of the pattern region by the lift-off method. That is, a radius of about 47 to 48 m which is the outer peripheral portion outside the pattern area
Within the range of m, there are approximately circular projections (spacers) having a height of 2.5 μm and a diameter of 50 μm at 100 μm intervals, and a radius of 1
A mask having spacers formed in the range of 5 to 16 mm, which was the same as the spacers on the outer peripheral portion except that the height was 0.5 μm, was obtained. The lift-off method was performed in substantially the same manner as the above-mentioned Al layer formation.

The energy in the pattern area of the mask is
The area of the gee ray transmission part is at least 56% or more.
It was Next, 3.5 inch diameter NiP plated aluminum
Cleaning and drying the aluminum alloy substrate, and the degree of vacuum reached on it:
1 x 10^-7Torr, substrate temperature: 350 ° C., bias voltage
Pressure: -200V, sputtering gas: Ar, gas pressure:
3 x 10^-3NiAl 60nm under the condition of Torr,
Cr₉₀Mo_TenIs 10 nm, and Co is used as the recording layer. ₆₄Cr₁₆P
t₁₂B₈Of 12 nm and carbon (diamond
And dry carbon) was deposited to a thickness of 5 nm.

Fluorine-based lubricant was applied as a lubricating layer thereon to a thickness of 0.5 nm and baked at 100 ° C. for 40 minutes,
Room temperature static coercive force 3600 Oe, dynamic coercive force 8000
An in-plane recording magnetic disk having a degree of Oe and a saturation magnetization of 310 emu / cc was obtained. The Curie temperature of the recording layer was 250 ° C. This disk is constructed so that the magnetic field direction of the electromagnet is the same as the rotating direction of the disk, and the magnetic field direction is about 10 kOe
The disk surface was magnetized uniformly (uniformly) by applying an intensity of (about 10 k Gauss).

The mask and the magnetic disk are integrally formed,
It was rotated at a speed of 1 rotation for 3.2 seconds. Wavelength 2 here
48nm excimer pulse laser pulse width: 25ns
ec, power (energy density): 160 mJ / c
m ² , beam shape: 10 mm × 30 mm (diameter that becomes 1 / e ^{2 of} peak energy), and install a shading plate that shapes the beam shape into a fan shape with an angle of 12 ° at the laser irradiation port, and repeat frequency at 10 Hz 32 pulses were irradiated. When the heating temperature was calculated by simulation, it was about 17
It was 0 ° C to 200 ° C.

At the same time, a magnetic field is applied by the magnetic field applying means,
An attempt was made to transfer the magnetization pattern. 2A is a plan view and FIG. 2B is a sectional view taken along line BB of the magnetization applying means according to this embodiment. A mask 14 is placed on the magnetic disk 11 via a spacer 17, a light shielding plate 13 is arranged above the mask 14, and an energy ray 15 is irradiated through the opening 13a. The mask 14 has a transmissive part and a non-transmissive part according to the magnetization pattern to be formed as described above.

Permanent magnets 12a (N pole) and 12b (S pole) are attached to both sides of the opening 13a in the light shielding plate 13, and an air-core coil (electromagnet) 18a in which the coil is wound several dozen times is formed. , 18b are the permanent magnets 12a, 12
It is arranged along b. Further, permanent magnets 12c (N pole) and 12d (S pole) are attached to the opposite surface of the magnetic disk 11, and air-core coils (electromagnets) 18a and 18b in which the coil is wound in a loop form dozens of times are provided. Permanent magnet 1
It is arranged along 2c and 12d.

The air core coils 18a and 18b are connected to each other by a conductive wire, and both ends thereof are connected to the DC power source 2
1, the capacitor 22, and the thyristor 23. Further, the air-core coils 18a and 18b are bent in a dogleg shape so that the magnetic disk 11 can be easily attached and detached. Here, by the permanent magnets 12a to 12d, in the circumferential direction of the magnetic disk in the direction opposite to the uniform magnetization,
A magnetic field of about 1.7 kGauss is constantly applied in the inner area of the disk (position with a radius of 21 mm) and about 1.9 kGauss in the outer area of the disk (position with a radius of 46.5 mm).

In order to apply the pulsed external magnetic field, first, the DC power supply 21 causes the capacitor 22 to have a potential difference of 750V. Next, when a trigger signal is generated from the trigger device 24 according to the timing of applying the external magnetic field and input to the gate terminal of the thyristor 23, a current difference is generated in the air core coils 18a and 18b due to the potential difference accumulated in the capacitor 22. It flows at once. With this pulsed current, the pulse width is 200 μsec around the coil, and the pulse width is about 1.
A pulsed magnetic field with a maximum strength of about 2.0 kGauss is generated in the disk outer peripheral region (position with a radius of 46.5 mm) at 8 kGauss.

As shown in FIG. 2B, the air-core coil 18
Since the magnetic fields generated by a and 18b act to assist the magnetic fields generated by the permanent magnets 12a to 12d, a total of about 3.5 k gauss in the disk inner peripheral area (position of radius 21 mm) and disk outer peripheral area (radius of 46.5 mm). Maximum strength at position 3.
A pulsed magnetic field of about 9 kGauss is applied. On the other hand, the trigger signal from the trigger device 24 is input to an energy ray source 26 such as an excimer laser (wavelength 248 nm) via a delay device (delay) 25, and thereby pulsed energy rays are generated. The energy beam passes through a programmable shutter, a beam expander, a prism array, etc., which are not shown, and then, for example, has a pulse width of several tens of nanoseconds.
It is irradiated as a pulse-like energy beam 5 having an energy density of 100 to 200 mJ / cm ² .

Normally, it takes time for the magnetic field to rise and fall due to the characteristics of the electromagnet, so that the energy beam 15 is radiated by the delay device 25 so that the energy beam 15 is irradiated just when the magnetic field strength is maximized. Adjust the emission time of. As a result, a pulsed magnetic field of about 3000 Oe is applied at the same time as the irradiation of the energy beam 15. The dynamic coercive force of the heating region of the magnetic disk 11 is 300.
Since it has dropped to 0 Oe or less, only the heating region is reverse-magnetized by the pulsed magnetic field, and the magnetization pattern is formed. The pulsed current may be directly supplied from the DC power supply without using a capacitor or the like.

FIG. 3 shows the temporal relationship between the magnetic field pulse and the laser light trigger pulse in the first embodiment. In addition,
The excimer pulse laser was irradiated about 4 μsec after the laser light trigger pulse was emitted. As can be seen from FIG. 3, the timing was adjusted so that the pulse laser was exactly irradiated when the magnetic field strength reached the maximum. The configuration of the optical system for laser irradiation used here is as follows. The pulse laser emitted from the excimer pulse laser light source passes through the programmable shutter. The programmable shutter serves to extract only desired pulses from the light source.

The output power of the laser selected by the programmable shutter is adjusted to a desired power, and then the laser passes through a prism array for dividing the minor axis direction into three and a prism array for dividing the major axis direction into seven. , To the projection lens. The prism array has a function of dividing and overlapping lasers to make the energy intensity distribution uniform.
These may also be referred to as homogenizers. Further, the laser is made to have a desired beam shape through a light shielding plate as necessary, and the intensity distribution is changed by a mask according to the magnetization pattern, and then the laser is projected on the disk.

When the magnetization pattern was formed as described above, the area of the second magnetization region in the initial magnetization region was at least 56% or more. FIG. 4 shows a reproduction signal waveform (differential signal waveform) of the magnetic disk obtained in Example 1 when the magnetization pattern was reproduced by the GMR head for a hard disk having a reproduction element width of 0.4 μm. The horizontal scale is 0.2 μs / Div, and the vertical scale is 52 mV / Div. As can be seen from the figure, a good signal with little noise was obtained.

By applying the method of this embodiment to the servo pattern formation of a magnetic disk, a magnetic disk having a highly precise servo pattern can be obtained simply and in a short time. Further, a magnetic disk device using this magnetic disk does not need to write a servo pattern newly, can perform tracking with high accuracy, and can perform recording with high density.

[0180]

According to the present invention, in a technique of forming a magnetization pattern on a magnetic recording medium by combining local heating and application of an external magnetic field, a fine magnetization pattern can be accurately formed without using a high power energy ray. It is possible to provide a method for forming a magnetic pattern that can be efficiently formed at low cost and a mask used for the method. As a result, it is possible to provide a magnetic recording medium and a magnetic recording device, which have less defects and enable high-density recording, in a short time and at low cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining an example of a magnetization pattern forming method according to the present invention.

2A and 2B are a plan view and a cross-sectional view showing a method of forming a magnetization pattern according to an example of the present invention.

FIG. 3 is a diagram showing a temporal relationship between a magnetic field pulse and a laser light trigger pulse in the example of the present invention.

FIG. 4 is a reproduction signal waveform (differential signal waveform) when a magnetization pattern is reproduced in an example of the present invention.

FIG. 5 is a schematic diagram for explaining an example of a magnetization pattern according to the present invention.

[Explanation of symbols]

1 magnetic recording medium (magnetic disk) 2 mask 3 external magnetic field 4 incident light (laser beam) 5 spacer 6 transparent substrate (quartz) 7 non-transmissive layer (chrome) 8 dielectric layer 11 magnetic disks 12a, 12b, 12c, 12d permanent Magnet 13 Light-shielding plate 13a Opening 14 Mask 15 Energy ray 17 Spacer 18a, 18b, 19a, 19b, 19c, 19d
Air core coil (electromagnet) 21 DC power supply 22 Capacitor 23 Thyristor 24 Trigger generator 25 Delay device (delay) 26 Energy ray source 31 Magnetization pattern forming region 32 Non-magnetization pattern forming region 33 Control pattern 41 First magnetization region 42 Second Magnetized area

Continued front page    (72) Inventor Yuzo Seo             1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa             Within Mitsubishi Chemical Corporation F-term (reference) 5D006 DA03 FA00                 5D091 AA10 BB08 CC17 CC26 GG33                       JJ25                 5D096 WW03

Claims (12)

[Claims] 1. A first external magnetic field is applied to a magnetic recording medium having a magnetic layer to magnetize the magnetic layer in a desired direction in advance to form an initial magnetization region having an initial magnetization direction, At the same time as locally heating the initial magnetization region of the magnetic layer by irradiating an energy ray, by applying a second external magnetic field to reverse the magnetization of the heating portion, the first magnetization region having the initial magnetization direction and the initial magnetization region are reversed. A method of forming a magnetization pattern composed of a second magnetization region having a magnetization direction opposite to the direction, wherein the second magnetization region exceeds 50% of the initial magnetization region. 2. The method for forming a magnetic pattern according to claim 1, wherein the magnetic layer is irradiated with the energy rays through a mask having a transmissive portion and a non-transmissive portion. 3. The medium is a magnetic disk, and as the magnetization pattern, a predetermined control pattern having control information of a recording / reproducing magnetic head is repeatedly formed at predetermined intervals in the circumferential direction of the magnetic disk. And a region between the adjacent predetermined control patterns is the second magnetization region,
The method for forming a magnetic pattern according to claim 1. 4. The magnetization pattern forming method according to claim 3, wherein the control pattern includes a servo pattern for controlling the position of the recording / reproducing magnetic head or a reference pattern for servo pattern recording. 5. A magnetic recording medium having a magnetic pattern formed by the method for forming a magnetic pattern according to any one of claims 1 to 4. 6. A magnetic recording medium having a magnetic pattern formed by the method for forming a magnetic pattern according to claim 1, a drive unit for driving the magnetic recording medium in a recording direction, a recording unit and a reproducing unit. And a recording / reproducing signal processing means for inputting a recording signal to the magnetic head and outputting a reproducing signal from the magnetic head. Characteristic magnetic recording device. 7. After incorporating a magnetic recording medium into the device,
A signal is obtained by reproducing the magnetization pattern with a magnetic head,
The magnetic recording device according to claim 6, wherein a servo burst signal is recorded by the magnetic head with the signal as a reference. 8. A first external magnetic field is applied to a magnetic recording medium having a magnetic layer to magnetize the magnetic layer in a desired direction in advance to form an initial magnetization region having an initial magnetization direction, The first magnetization having the initial magnetization direction is obtained by irradiating an energy ray through the mask to locally heat the initial magnetization region of the magnetic layer, and at the same time, by applying a second external magnetic field to reverse the magnetization of the heating portion. A mask used in a method of forming a magnetization pattern composed of a region and a second magnetization region having a magnetization direction opposite to an initial magnetization direction, the mask being a non-transmission part of an energy ray and a non-transmission part depending on a magnetization pattern to be formed. A mask having a pattern region formed of a transparent portion, wherein the area of the energy ray transparent portion in the pattern region exceeds 50%. 9. The mask according to claim 8, wherein the mask is manufactured by a lift-off method. 10. The mask comprises a substrate transparent to the energy rays and a non-transmissive non-transmissive layer, and the substrate is provided with recesses corresponding to a magnetization pattern to be formed. A non-transmissive layer is formed on at least the recess,
The mask according to claim 8 or 9. 11. The medium is a magnetic disk, and as the magnetization pattern, a predetermined control pattern having control information of a recording / reproducing magnetic head is repeatedly formed at predetermined intervals in the circumferential direction of the magnetic disk. The mask according to any one of claims 8 to 10, wherein a region corresponding to a space between the adjacent predetermined control patterns is the transparent portion. 12. The mask according to claim 11, wherein the control pattern includes a servo pattern for controlling the position of the recording / reproducing magnetic head or a reference pattern for recording the servo pattern.