JP2002203315A - Magnetic recording method - Google Patents

Abstract

(57) [Problem] In a preformat recording technique using a master information carrier, the recording capacity of a future high coercive force medium is lacking, and the magnetic disk is brought into contact with the master information carrier by a foreign substance so that the Possibility of causing defects in the disk and lack of reliability. SOLUTION: A photomask 4 in which a mask pattern corresponding to an information signal array is formed on a surface of a non-magnetic substrate 5 on a surface of a magnetic recording medium 1 which has been DC-erased in a uniform direction in advance.
Are arranged to face each other in a non-contact state. By irradiating light through the photomask 4 and locally heating the irradiated portion of the surface of the magnetic recording medium 1 with the light energy according to the mask pattern corresponding to the information signal arrangement, A recording magnetization pattern corresponding to the information signal arrangement is thermomagnetically recorded on the surface of the recording medium 1. Since the photomask 4 and the magnetic recording medium 1 are not in contact, preformat recording with excellent reliability is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording method used to record digital information signals on a magnetic recording medium at low cost and with good productivity.

[0002]

2. Description of the Related Art At present, magnetic recording / reproducing apparatuses tend to have a high recording density in order to realize a small size and a large capacity.
In the field of hard disk drives, which are typical magnetic recording / reproducing devices, the areal recording density is already 20 Gbit / s.
More than ² devices have been commercialized, and a few years later,
The rapid technological progress is so great that practical application of 50 Gbit / in ² is discussed.

The technical background that has enabled such a high recording density is to improve the magnetic recording medium performance, the head-disk interface performance, and the linear recording density due to the emergence of new signal processing methods such as partial response. Is also a major factor.

[0004] In recent years, however, the trend of increasing the track density has greatly exceeded the trend of increasing the linear recording density, which is a major factor for improving the areal recording density. this is,
This is a contribution from the practical use of a magnetoresistive element type head which is much more excellent in reproduction output performance than a conventional induction type magnetic head.

At present, the practical use of a magnetoresistive element type head makes it possible to reproduce a track width signal of several μm or less with good S / N. On the other hand, it is expected that the track pitch will reach the submicron region in the near future with further improvement in head performance in the future.

For the head to accurately scan such a narrow track and reproduce a signal with good S / N, the tracking servo technique of the head plays an important role. With respect to such tracking servo technology, in a current hard disk drive, a tracking servo signal, an address information signal, a clock signal, and the like are recorded at a constant angular interval in one round of the disk, that is, within 360 degrees in angle. An area is provided (hereinafter, referred to as a preformat). By reproducing these signals at regular intervals, the magnetic head can accurately scan the track while confirming and correcting the position of the head.

The above-described tracking servo signal, address information signal, clock signal, and the like serve as reference signals for the head to accurately scan the track.
During the recording, accurate positioning accuracy is required.

In a current hard disk drive, after a disk is incorporated in the drive, preformat recording is performed by a magnetic head whose position is strictly controlled using a dedicated servo recording device.

Conventionally, there have been the following problems in preformat recording of a tracking servo signal, an address information signal, and a clock signal by a magnetic head using the above-described dedicated servo recording device.

First, recording by a magnetic head is basically linear recording based on the relative movement between the head and a magnetic recording medium. Therefore, in the above-described method of performing recording while strictly controlling the position of the magnetic head using a dedicated servo recording device, preformat recording requires a lot of time, and the dedicated servo recording device is considerably expensive. This results in a very high cost.

Second, the magnetic transition at the end of the track on which preformat recording is performed lacks sharpness due to the expansion of the recording magnetic field due to the spacing between the head and the magnetic recording medium and the pole shape of the recording head. The current tracking servo technology detects the position of the head based on the amount of change in the reproduction output when the head scans off the track. Therefore, the signal track on which the preformat recording is performed is not only excellent in S / N when the head accurately scans the track, such as when reproducing the data information signal recorded between the servo areas, but also in the head. Is required to have a steep reproduction output change amount when scanning off the track, that is, off-track characteristics.

The above problem is contrary to this requirement, and makes it difficult to realize an accurate tracking servo technique in future submicron track recording.

As means for solving the problem of preformat recording by a magnetic head as described above, the present inventors have disclosed in Japanese Patent Application Laid-Open No. 10-45544 a specification that corresponds to an information signal on the surface of a base. By bringing the surface of the master information carrier on which the ferromagnetic thin film pattern is formed into contact with the surface of the magnetic recording medium, the magnetization pattern corresponding to the ferromagnetic thin film pattern on the surface of the master information carrier can be batch-transfer-recorded onto the magnetic recording medium. The main pre-formatting technology is proposed.

In the configuration disclosed in Japanese Patent Application Laid-Open No. 10-45544, the magnetic recording medium generates a ferromagnetic thin film on the surface of the master information carrier which is magnetized in one direction, and the magnetic recording medium has a ferromagnetic material. A magnetization pattern corresponding to the thin film pattern is transferred and recorded. That is, a ferromagnetic thin film pattern corresponding to a tracking servo signal, an address information signal, a clock signal, etc. is formed on the surface of the master information carrier by a photolithography technique or the like, and a preformat corresponding to these is formed on a magnetic recording medium. Records can be made.

The recording by the conventional magnetic head is basically a dynamic linear recording based on the relative movement between the head and the magnetic recording medium. That is, it is a static surface record that does not involve relative movement in a state where it is in contact with each other. Due to such features, the technology disclosed in Japanese Patent Application Laid-Open No. H10-40544 can exert the following extremely effective effects on the above-described problem relating to preformat recording.

First, because of surface recording (collective surface transfer recording), the time required for preformat recording is very short as compared with the conventional recording method using a magnetic head. Also,
There is no need for an expensive dedicated servo recording device for performing recording while strictly controlling the position of the magnetic head. Therefore, productivity related to preformat recording can be significantly improved, and production cost can be reduced.

Second, since static recording (collective surface transfer recording) is performed without relative movement between the master information carrier and the magnetic recording medium, recording is performed by bringing the master information carrier surface into close contact with the magnetic recording medium surface. Spacing between the two can be minimized. Furthermore, unlike the recording by the magnetic head, the recording magnetic field does not spread due to the pole shape of the recording head. For this reason, the transition of the magnetization at the end of the track on which the preformat recording is performed has an excellent steepness as compared with the recording by the conventional magnetic head, and more accurate tracking is possible.

[0018]

However, the preformatting technique disclosed in Japanese Patent Application Laid-Open No. 10-45544 has the following problems.

First, according to the technique disclosed in Japanese Patent Application Laid-Open No. H10-45544, if the coercive force of a magnetic recording medium exceeds a certain value in the future, sufficient recording capability cannot be exhibited. There is. That is, the magnetic recording medium tends to rapidly increase the coercive force in order to realize high-density recording. According to the study of the present inventors, in order to exhibit a sufficient recording capability with respect to such a high coercive force medium, the ferromagnetic thin film on the master information carrier needs to be about three times the coercive force of the magnetic recording medium. It is necessary to have the above saturation magnetization. For example, at present, the general coercive force of a hard disk is about 300 kA / m or less, so that the ferromagnetic thin film on the master information carrier only needs to have a saturation magnetization of 900 kA / m or more.

In the future, however, the saturation magnetization of the ferromagnetic thin film on the master information carrier cannot be increased indefinitely in response to the increasingly higher coercive force of the magnetic recording medium. Among the existing ferromagnetic materials, those having the highest saturation magnetization are about 1900 kA / m. In addition, considering that it is necessary to select an appropriate film composition to ensure the high magnetic permeability characteristics and corrosion resistance required for the ferromagnetic thin film for the master information carrier, the ferromagnetic thin film that can be used for the master information carrier Is estimated to be about 1600 kA / m as the upper limit.

Therefore, the coercive force of the magnetic recording medium is 500 kA / m
In the case where it becomes larger than
It is expected that the technique disclosed in Japanese Patent Application Publication No. 4-4 cannot exert sufficient recording capability.

Second, in the technique disclosed in Japanese Patent Application Laid-Open No. 10-45544, it is necessary to bring the surface of the master information carrier into contact with the surface of the magnetic recording medium.

In the technique disclosed in Japanese Patent Application Laid-Open No. 10-45544, it is important to bring the surface of the master information carrier into contact with the surface of the magnetic recording medium. When recording is performed with a fixed interval provided without contacting both surfaces, signal quality deteriorates due to spacing loss as in the case of magnetic recording technology using a magnetic head.

Further, it is technically difficult to control so as to uniformly provide a constant minute distance with the master information carrier over the entire surface of a magnetic recording medium having a constant area such as a magnetic disk.

In the preformat technique disclosed in Japanese Patent Application Laid-Open No. 10-45544, the master information carrier is brought into contact with the magnetic recording medium. If any foreign matter intervenes between the information carrier surface and the magnetic recording medium surface, there is a possibility that defects such as scratches may occur on the magnetic recording medium surface. When such a scratch is generated on the magnetic recording medium, not only a problem that a signal defect is generated in this portion, but also the scratch may be triggered and the magnetic head may crash. So you can no longer use it mounted on the drive.

By the way, in order to perform such a defect inspection of the magnetic recording medium, a certification test is usually performed before the magnetic recording medium is incorporated in the drive. This is to detect a defect on the magnetic recording medium by performing a predetermined recording / reproducing test using a magnetic head on the entire surface of the completed magnetic recording medium.

However, such a certify test cannot be performed on a magnetic recording medium on which a signal is recorded using the preformat technique disclosed in Japanese Patent Application Laid-Open No. 10-45544. This is because the preformatted information signal recorded at an angle is erased by the whole-surface recording / reproducing test using the magnetic head.

As described above, the preformat technique disclosed in Japanese Patent Application Laid-Open No. 10-45544 has a disadvantage that a defect on a magnetic recording medium is likely to be caused by contact with a master information carrier. There is a problem that there is no way to inspect a defect caused by this recording operation.

In order to solve the first and second problems described above, the recording medium has the same productivity and recording accuracy as the preformatting technique disclosed in Japanese Patent Laid-Open No. It is expected that a highly reliable recording technique will be established at an early stage from the viewpoint of recording medium defects.

The present invention has been made in view of the above problems, and
A means for realizing preformat recording that has the same productivity and recording accuracy as the preformat technology disclosed in Japanese Patent No. 40544, and is highly reliable from the viewpoint of recording capability and magnetic recording medium defects. The purpose is to:

[0031]

The present invention solves the above-mentioned problems by taking the following measures.

The surface of a magnetic recording medium on which information signals such as preformat information signals are to be collectively surface-recorded by preformat recording is DC-erased in advance. A photomask used for preformat recording has a mask pattern corresponding to the arrangement of the information signals. The photomask is arranged so as to be in contact with or not in contact with the surface of the magnetic recording medium. Light is irradiated from the side opposite to the magnetic recording medium with respect to the photomask. The irradiation light is blocked at the mask portion of the photomask, but is transmitted at the transmission portion and reaches the surface of the magnetic recording medium, where it is locally heated. The locally heated portion is the irradiated portion. In the photomask, a mask pattern, which is a pattern formed by weaving a mask portion and a transmission portion, corresponds to an information signal array.

Light energy is converted into heat energy at the irradiated portion on the surface of the magnetic recording medium, and the irradiated portion is locally heated. When the surface of the magnetic recording medium is heated to, for example, the vicinity of the Curie temperature of the magnetic layer, the magnetization locally disappears in the heated portion. When the irradiation light is cut off in this state, the heated portion is gradually cooled naturally, and in the process, is magnetized to the opposite polarity to the initial magnetization by a floating magnetic field generated from the initial magnetization of the adjacent non-heated region. Thus, the magnetization is reversed.

In the case of a perpendicular magnetic recording medium, inversion magnetization can be generated only by a floating magnetic field of initial magnetization, but there is an option of applying a DC bias magnetic field to obtain an auxiliary magnetic field. In the case of an in-plane magnetic recording medium, application of a direct-current bias magnetic field is necessary because inversion magnetization cannot be generated only by the floating magnetic field of the initial magnetization. In any case, the DC bias magnetic field is in a direction opposite to the initial magnetization (preliminary DC erasing magnetic field).

As a result, on the surface of the magnetic recording medium, an information signal array pattern in which initial magnetization based on DC erasure and inverted magnetization after heating magnetization disappears are alternately arranged corresponding to the mask pattern in the photomask. Will be done. This is collective surface recording of information signals by thermomagnetic recording.

In the collective surface recording of information signals by thermomagnetic recording, assuming that there is no initial magnetization but only inversion magnetization, this is contrary to the principle of alternate arrangement of positive direction magnetization and negative direction magnetization. In addition, generation of reversal magnetization due to a stray magnetic field is also eliminated. Therefore, the principle of the alternating arrangement of the positive direction magnetization and the negative direction magnetization requires the initial magnetization, and in order to secure the initial magnetization, the surface of the magnetic recording medium must be DC-erased before light irradiation. I do it.

The above configuration can be described as follows in comparison with the prior art. In the case of the prior art,
Since the magnetization is not temporarily lost due to active heating, the saturation magnetization of the ferromagnetic thin film on the master information carrier must be sufficient for the coercive force of the magnetic recording medium to ensure the function of generating the reversal magnetization. It needed to be bigger. That is, according to the study of the present inventors, it is necessary that the saturation magnetization is at least three times the coercive force of the magnetic recording medium.

On the other hand, in the present invention, recording is performed by heating the magnetic layer of the magnetic recording medium to the vicinity of the Curie temperature to eliminate the magnetization of the heated portion. In this state, the heated portion is locally in a non-magnetic state and has no coercive force. Therefore, it is not necessary to provide a high saturation magnetization in the ferromagnetic thin film on the master information carrier in order to cause a magnetization reversal in the heated part.

In the configuration of the present invention, a photomask having a mask pattern corresponding to the arrangement of information signals can be arranged so as to face the magnetic recording medium surface in a non-contact state. Then, light is irradiated from the side opposite to the magnetic recording medium with respect to the photomask.

With respect to such a configuration, the following can be said in comparison with the prior art. In the case of the prior art, since the magnetization is not temporarily lost due to active heating, it is necessary to bring the master information carrier into contact with the surface of the magnetic recording medium in order to ensure the function of generating the reversal magnetization. Was. If they are separated, there are problems of spacing loss and non-uniform magnetization. However, in the contact state, there are problems of signal loss and head crash due to foreign matter. In the case of a certify test for inspecting a defect such as a signal drop due to a foreign substance, when this test is performed, the information signal itself recorded on the entire surface is erased. If the state is left as it is, the inspection for the defect due to the foreign matter cannot be performed.

On the other hand, according to the present invention, the problems in the prior art as described above can be effectively solved as follows.

In the master information carrier of the prior art, the magnetization unit having the unit of the positive direction magnetization or the negative direction magnetization is specified with or without the ferromagnetic thin film of the ferromagnetic thin film pattern. In the photomask of the present invention, it is a transmission portion and a mask portion.

In the prior art, the portion of the master information carrier having the ferromagnetic thin film is convex, and the convex portion comes into contact with the surface of the other magnetic recording medium and the concave portion is separated. The positive magnetization and the negative magnetization are separated from each other on the surface of the magnetic recording medium.

On the other hand, in the present invention, the irradiation light is transmitted through the transmitting portion of the photomask, the irradiated portion on the surface of the magnetic recording medium is demagnetized by heating, and the irradiation light is blocked at the mask portion. The non-irradiated portion on the surface of the magnetic recording medium is not lost in magnetization, thereby separating the positive direction magnetization and the negative direction magnetization on the surface of the magnetic recording medium.

In the prior art, the direction of the magnetic field outside the convex portion and the direction of the magnetic field outside the concave portion are opposite to each other with respect to the magnetic field created in the space by the initial magnetization in the convex portion having the ferromagnetic thin film. However, by contacting the surface of the magnetic recording medium with the master information carrier by the magnetic field emitted from such a master information carrier, the energy of the magnetic field on the master information carrier side is applied to the surface of the magnetic recording medium in the forward magnetization. And negative direction magnetization are transferred.

On the other hand, in the present invention, the magnetic field that causes the surface of the magnetic recording medium to be divided into the positive direction magnetization and the negative direction magnetization is present in the photomask on the other side. Instead, it exists in the magnetic recording medium itself. that is,
This is a magnetic field due to DC erase magnetization in DC erase in a magnetic recording medium. When the magnetization disappears in the region heated by the light irradiation, the magnetic field due to the DC erasing magnetization becomes a floating magnetic field, and reversely magnetizes the portion where the magnetization disappears. This is the reversal magnetization.

In the prior art, the magnetic transfer of magnetization-magnetic field-magnetization is performed from the master information carrier to the surface of the magnetic recording medium, so that the contact between the master information carrier and the surface of the magnetic recording medium is essential. This is the biggest cause of foreign matter problems.

On the other hand, in the present invention, a magnetic field as a source of the reversal magnetization on the surface of the magnetic recording medium exists on the surface of the magnetic recording medium itself. That is, the magnetic field of the magnetic recording medium is supplied by itself, instead of being supplied with the magnetic field of the source from the photomask on the other side. Therefore, the binding is released from the need to bring the surface of the magnetic recording medium into contact with the photomask, and the surface of the magnetic recording medium is allowed to be separated from the photomask.

According to the present invention, information for specifying the position on the plane of which part of the surface of the magnetic recording medium is to be subjected to generation of reversal magnetization through demagnetization and which part is not to be subjected to a photomask. Irradiation light is used to transmit light from the magnetic recording medium to the surface of the magnetic recording medium. Moreover, the light energy of the irradiation light also causes the disappearance of magnetization due to heating.

Metaphorically speaking, in the case of the prior art, the magnetization-magnetic field-magnetization of the same physical element called the magnetization pattern directly from the magnetization pattern on the master information carrier to the magnetization pattern on the surface of the magnetic recording medium. In contrast to magnetic transfer, in the present invention, the mechanism is such that planar position information on a photomask is transmitted to the surface of a magnetic recording medium, and a magnetization pattern is generated in accordance with the transmitted position information. I have.

In short, in any case, the present invention is not the magnetic transfer of the magnetization-magnetic field-magnetization of the same physical element from the master information carrier to the surface of the magnetic recording medium. DC erasing, non-contact between the photomask and the surface of the magnetic recording medium, transmission of positional information on a plane such as light transmission and light blocking by light irradiation through the photomask, and heating through the light energy of irradiation light Due to a very special mechanism, such as the generation of reversal magnetization due to the disappearance of the magnetization and the appearance of the stray magnetic field,
This realizes thermomagnetic recording of a highly accurate recording magnetization pattern in a non-contact state.

In the present invention, since magnetization is temporarily lost due to active heating, even if the photomask is separated from the surface of the magnetic recording medium, the problems of spacing loss and uneven magnetization can be avoided. In addition, the function of generating the reversal magnetization can be sufficiently ensured. As described above, the photomask is allowed to be in a non-contact state with respect to the surface of the magnetic recording medium. As a result, the problem of signal loss or head crash due to foreign matter caused by the contact can be avoided. Therefore, a certification test for inspecting a defect such as a signal drop due to a foreign substance is released from the necessity of executing the certification test.

As in the case of the prior art, the recording does not involve relative movement between the magnetic recording medium and the photomask, but performs static batch recording in which the pattern on the photomask is reflected in the irradiated portion. Productivity and recording accuracy can be ensured.

In summary, according to the present invention, while the excellent productivity and recording accuracy are ensured due to the static batch recording, the disappearance of the magnetization once due to the active heating by light irradiation is prevented. Because of this, while avoiding the problems of spacing loss and non-uniform magnetization, the function of generating reversal magnetization is sufficiently ensured even for future high coercive force magnetic recording media. By ensuring the separation of the photomask and avoiding the problem of signal loss and head crash due to foreign matter caused by the contact, high reliability can be achieved without waiting for a certification test.

It should be noted that, in the above description, the transmission of position information on a plane and the disappearance of magnetization due to heating are shared by light irradiation. However, it is conceivable that this can be achieved by separate physical elements. This will be a future research topic. Furthermore, as technology advances in the development of new materials in the future, heating is not necessarily required, and it is expected that magnetization can be performed without heating. It is also conceivable to use physical elements other than light for transmitting the planar position information.

[0056]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be generally described.

According to the magnetic recording method of the first invention of the present application, a photomask having a mask pattern corresponding to an information signal arrangement is arranged in contact with the surface of a magnetic recording medium which has been DC-erased in advance. By locally heating the irradiated portion of the surface of the magnetic recording medium by light energy radiated to the surface of the magnetic recording medium through the magnetic recording medium, a recording magnetization pattern corresponding to the information signal arrangement is thermally formed on the surface of the magnetic recording medium. It is characterized by magnetic recording.

According to the magnetic recording method of the second invention of the present application, a photomask having a mask pattern corresponding to an information signal arrangement is arranged in a non-contact state with respect to a surface of a magnetic recording medium which has been DC-erased in advance. By locally heating the irradiated portion of the magnetic recording medium surface with light energy radiated to the magnetic recording medium surface through a mask, a recording magnetization pattern corresponding to the information signal array is formed on the magnetic recording medium surface. It is characterized by performing thermomagnetic recording.

The structure of the first and second aspects of the invention corresponds to the structure of the above-mentioned [Means for Solving the Problems] section described in another form of expression. This is substantially the same as that described in the above section [Means for Solving the Problems]. In other words, while maintaining excellent productivity and recording accuracy due to static batch recording, the problem of spacing loss and non-uniform magnetization due to the temporary disappearance of magnetization based on active heating by light irradiation is involved. While avoiding it, the function of generating reversal magnetization is sufficiently secured even for future high coercivity magnetic recording media, and in addition, the separation of the photomask from the surface of the magnetic recording medium is ensured, and contact may be caused. High reliability can be achieved without having to wait for a certification test by avoiding the problem of signal loss or head crash due to foreign matter.

The magnetic recording method according to a third aspect of the present invention is the magnetic recording method according to the first and second aspects, wherein when the irradiated portion of the surface of the magnetic recording medium is locally heated, the magnetic recording medium is subjected to DC erasure. It is characterized in that a DC bias magnetic field having a polarity opposite to that of the initial magnetization is applied.

The operation according to the third aspect of the invention is as follows. In the case of a perpendicular magnetic recording medium, inversion magnetization can be generated only by the floating magnetic field of the initial magnetization, but the generation of inversion magnetization may be insufficient. Therefore, if a DC bias magnetic field is applied to generate an auxiliary magnetic field for inversion magnetization generation, sufficient inversion magnetization can be generated even when the generation of inversion magnetization is insufficient only with the floating magnetic field of the initial magnetization.

In the case of an in-plane magnetic recording medium, since a reversal magnetization cannot be generated only by the floating magnetic field of the initial magnetization, it is necessary to apply a DC bias magnetic field. The present invention can be made effective.

The magnetic recording method according to a fourth aspect of the present invention is the magnetic recording method according to the third aspect, wherein in applying the DC bias magnetic field, a DC bias magnetic field smaller than a coercive force in a non-heating region of the magnetic recording medium is applied. It is characterized by the following.

The operation according to the fourth aspect of the invention is as follows. The magnitude of the DC bias magnetic field must not be so great as to exceed the coercivity of the unheated area. This is because, when a large DC bias magnetic field exceeding the coercive force of the non-heating area is applied, the initial magnetization of the non-heating area may be demagnetized or demagnetized. By responding as described above, good thermomagnetic recording can be performed without demagnetization or demagnetization of the initial magnetization.

According to a fifth aspect of the present invention, there is provided the magnetic recording method according to the first to fourth aspects, wherein the magnetic recording medium is
The thermomagnetic recording is performed on a perpendicular magnetic recording medium whose magnetic layer has an axis of easy magnetization in a direction normal to the surface of the magnetic layer.

The operation of the fifth invention is as follows. As is well known, a perpendicular magnetic recording medium has a much higher recording density than an in-plane magnetic recording medium. In such a high recording density perpendicular magnetic recording medium, countermeasures against foreign matter are extremely important. Since the present invention exerts the above-described excellent functions as a measure against foreign matter, it is possible to realize excellent productivity and excellent reliability for a perpendicular magnetic recording medium having a high recording density.

The magnetic recording method according to a sixth aspect of the present invention is the magnetic recording medium according to the fifth aspect, wherein the magnetic layer is made of an amorphous metal alloy having a ferrimagnetism and a rare earth and a transition metal as main components. When locally heating the irradiated portion of the magnetic recording medium surface,
The irradiated portion is heated to a temperature near the compensation temperature of the magnetic layer.

The operation of the sixth invention is as follows. When a perpendicular magnetic recording medium composed of an amorphous alloy thin film containing a rare earth element and a transition metal as a main component is used as the magnetic recording medium, the temperature at which the initial magnetization disappears due to DC erasure can be lowered, thereby conserving energy. Is more preferable in terms of In particular, Gd (gadolinium), T
Many amorphous alloy thin films mainly composed of heavy rare earths such as b (terbium) and Dy (dysprosium) and transition metals have ferrimagnetism, so that magnetization is lost at a compensation temperature sufficiently lower than the Curie temperature. Can be. By controlling the composition ratio of the rare earth element and the transition metal element, the compensation temperature can be controlled in a wide range as long as the performance of the perpendicular magnetic recording medium is not affected. Therefore, according to the embodiment, by setting the compensation temperature of the magnetic recording medium to be slightly higher than the operating environment temperature of the magnetic recording / reproducing apparatus, it is possible to use a relatively low-power irradiation light to achieve a sufficiently efficient operation. It is possible to perform a preformat recording.

The magnetic recording method according to a seventh aspect of the present invention is the magnetic recording method according to the first to sixth aspects, wherein the magnetic recording medium is heated by irradiating light onto the entire surface of the photomask. It is characterized in that it is performed by parallel light. By using the parallel light, it is possible to irradiate the photomask and the surface of the magnetic recording medium perpendicular to the surface of the magnetic recording medium uniformly (uniformly) over a large area, thereby improving the recording resolution and the quality accuracy.

According to an eighth aspect of the present invention, in the magnetic recording method according to the first to sixth aspects, the magnetic recording medium is heated by irradiating the magnetic recording medium with a laser beam which is scanned along the surface of the photomask. It is characterized by the following.

The operation of the eighth invention is as follows. This describes spot irradiation, not surface irradiation. By scanning the laser beam along the surface of the photomask, preformat recording over the entire surface of the magnetic recording medium is completed. Since batch recording cannot be performed over the entire surface of the magnetic recording medium, productivity associated with preformat recording is slightly sacrificed.
However, compared with the minimum recording unit (bit area of a signal recorded on a magnetic recording medium) in linear recording using a conventional magnetic head, the spot size of the laser beam is at least ¹⁰⁸ times or more (however, this numerical value is an example). ), And therefore has a great advantage in terms of productivity as compared with the preformat recording using the conventional magnetic head. Since the laser beam has a large power density and is a coherent light beam, the reliability and accuracy of the generation of the magnetization pattern on the surface of the magnetic recording medium are extremely high.

The magnetic recording method according to a ninth aspect of the present invention is the magnetic recording method according to the second to seventh aspects, wherein a lens is interposed between the photomask and the magnetic recording medium disposed opposite to each other. The mask pattern corresponding to the information signal array on the photomask is reduced and projected on the surface of the magnetic recording medium by refracting the irradiation light through the photomask.

The operation according to the ninth invention is as follows. By performing reduction projection using a lens, even when the bit length of an information signal recorded on a magnetic recording medium is a very small value of, for example, about 0.25 μm, a mask pattern corresponding to this information signal array is provided. May be provided on the photomask in a relatively large size of several times to several tens of times. This makes it easy to manufacture the photomask and reduces the manufacturing cost. In this way, the lens can be interposed between the photomask and the magnetic recording medium because the non-contact mode is the most important point of the present invention.
The invention provides an even more advantageous technical development.

(Specific Embodiment) Hereinafter, a specific embodiment of a magnetic recording method according to the present invention will be described in detail with reference to the drawings.

The magnetic recording method according to the embodiment of the present invention will be described with reference to FIG.
This will be described with reference to the sectional view of FIG.

First, as shown in FIG. 1A, a DC erasing magnetic field 2 is applied to a perpendicular magnetic recording medium 1 so that DC erasure is performed uniformly in the film normal direction of the magnetic recording medium 1. As a result, a uniform DC erase magnetization 3 is formed on the entire surface of the perpendicular magnetic recording medium 1.

Next, as shown in FIG. 1B, the photomask 4 is brought into contact with the surface of the magnetic recording medium 1 from which the direct current has been erased, and irradiation light 7 is irradiated. For the irradiation of the irradiation light 7, an ultraviolet light source or a laser light capable of uniformly irradiating parallel light over a large area can be used.

In the photomask 4, a mask pattern corresponding to an information signal array is formed by a metal mask film 6 on a non-magnetic substrate 5 that can transmit the irradiation light 7. Since the irradiation light 7 cannot pass through the metal mask film 6,
Only in the portion where the metal mask film 6 is not formed,
The surface of the magnetic recording medium 1 is locally irradiated, and the surface of the magnetic recording medium can be heated in this portion.

When the surface of the magnetic recording medium is heated to, for example, the vicinity of the Curie temperature of the magnetic layer, the magnetization locally disappears in the heated portion. When the irradiation light is blocked in this state,
The heated portion is gradually cooled spontaneously, and is magnetized in the process by the stray magnetic field 8 generated from the initial magnetization 3 ′ of the adjacent non-heated portion to have a polarity opposite to that of the initial magnetization 3 ′. As a result, in the magnetic recording medium 1, as shown in FIG. 1C, the initial magnetization 3 ′ and the reversal magnetization 9 based on the DC erasing correspond to the metal mask film pattern formed on the photomask 4. Information signal arrangement patterns arranged alternately are recorded.

In the magnetic recording method of the present embodiment described above, static batch recording that reflects the pattern on the photomask 4 is performed in the portion irradiated with the irradiation light. Therefore, as with the preformat technology disclosed in Japanese Patent Application Laid-Open No. H10-45544, it has excellent productivity and recording accuracy.

On the other hand, in the present embodiment, the portion where the magnetization reversal is to be caused is locally heated to erase the magnetization and coercive force, and the recording is performed. Therefore, the problems of spacing loss and non-uniform magnetization are avoided. In addition, it is possible to sufficiently secure the function of generating reversal magnetization even in a future high coercivity magnetic recording medium.

That is, according to the magnetic recording method of the present invention, as in the preformat recording method disclosed in Japanese Patent Application Laid-Open No. 10-45544, the ferromagnetic thin film of the master information carrier has a coercive force of three times or more of the magnetic recording medium. It is not necessary to provide a saturation magnetic flux density. Therefore, it is possible to solve the problem of the related art that sufficient recording performance cannot be obtained for a high-coercivity magnetic recording medium in the future.

Here, in the process of irradiating the surface of the magnetic recording medium 1 with the irradiation light through the photomask 4 and in the process of blocking the irradiation light and naturally cooling the irradiated portion, FIG.
As shown in (b), a constant DC bias magnetic field 10 may be applied. This DC bias magnetic field 10 is applied with a polarity opposite to that of the DC erasing magnetic field 2 and the remaining DC erasing magnetization 3 and is sufficient when the floating magnetic field 8 generated from the initial magnetization 3 ′ of the non-heated portion is not sufficiently large. It functions as an auxiliary magnetic field for generating a large reverse magnetization 9.

The magnitude of the DC bias magnetic field 10 must not be so large as to exceed the coercive force of the unheated part. When a large DC bias magnetic field 10 exceeding the coercive force of the non-heated portion is applied, the initial magnetization 3 ′ of the non-heated portion is increased.
May be demagnetized or demagnetized, and it is necessary to find an optimum value at a value smaller than the coercive force of the non-heated portion according to the embodiment. FIG. 3 is a cross-sectional view of a magnetic recording method according to another embodiment of the present invention, which is different from the method shown in FIGS. 1 and 2, taking a case of signal recording on a perpendicular magnetic recording medium as an example. It will be described with reference to FIG.

First, as shown in FIG. 3A, a DC erasing magnetic field 2 is applied to the perpendicular magnetic recording medium 1 to perform DC erasing uniformly in the film normal direction of the magnetic recording medium 1. As a result, a uniform DC erase magnetization 3 is formed on the entire surface of the perpendicular magnetic recording medium 1.

Next, as shown in FIG. 3B, the photomask 4 is brought close to the surface of the DC-erased magnetic recording medium 1 in a non-contact state without contact, and irradiation light 7 is irradiated.
For the irradiation of the irradiation light 7, an ultraviolet light source or a laser light capable of uniformly irradiating parallel light over a large area can be used.

In the photomask 4, a mask pattern corresponding to the information signal arrangement is formed by a metal mask film 6 on a non-magnetic substrate 5 that can transmit the irradiation light 7. Since the irradiation light 7 cannot pass through the metal mask film 6,
Only in the portion where the metal mask film 6 is not formed,
The surface of the magnetic recording medium 1 is locally irradiated, and the surface of the magnetic recording medium can be heated in this portion.

When the surface of the magnetic recording medium is heated to, for example, the vicinity of the Curie temperature of the magnetic layer, the magnetization locally disappears at the heated portion. When the irradiation light is blocked in this state,
The heated portion is gradually cooled spontaneously, and is magnetized in the process by the stray magnetic field 8 generated from the initial magnetization 3 ′ of the adjacent non-heated portion to have a polarity opposite to that of the initial magnetization 3 ′. As a result, in the magnetic recording medium 1, as shown in FIG. 1C, the initial magnetization 3 ′ and the reversal magnetization 9 based on the DC erasing correspond to the metal mask film pattern formed on the photomask 4. Information signal arrangement patterns arranged alternately are recorded.

In the magnetic recording method of the present embodiment described above, static batch recording that reflects a pattern on a photomask is performed in a portion irradiated with irradiation light. Therefore, as with the preformat technology disclosed in Japanese Patent Application Laid-Open No. H10-45544, it has excellent productivity and recording accuracy.

On the other hand, in the magnetic recording method of the present embodiment, since the photomask and the magnetic recording medium do not come into contact with each other, there is no possibility that a defect present on the surface of the magnetic recording medium due to the foreign matter interposed between them. .

Therefore, the magnetic recording method of the present invention can also improve the reliability, which has been a problem in the preformat recording disclosed in Japanese Patent Application Laid-Open No. 10-45544. A certification test for defects due to foreign matter is not required. Here, in the process of irradiating the irradiation light to the surface of the magnetic recording medium 1 through the photomask 4 and in the process of blocking the irradiation light and naturally cooling the irradiated portion,
As shown in FIG. 4B, a constant DC bias magnetic field 10
May be applied. This DC bias magnetic field 10 is applied with a polarity opposite to that of the DC erasing magnetic field 2 and the remaining DC erasing magnetization 3 and is sufficient when the floating magnetic field 8 generated from the initial magnetization 3 ′ of the non-heated portion is not sufficiently large. It functions as an auxiliary magnetic field for generating a large reverse magnetization 9.

The magnitude of the DC bias magnetic field 10 must not be so large as to exceed the coercive force of the unheated part. When a large DC bias magnetic field 10 exceeding the coercive force of the non-heated portion is applied, the initial magnetization 3 ′ of the non-heated portion is increased.
May be demagnetized or demagnetized, and it is necessary to find an optimum value at a value smaller than the coercive force of the non-heated portion according to the embodiment.

As a magnetic recording medium suitable for the magnetic recording method of the present embodiment shown in FIGS. 1 to 4, an alloy thin film containing Co and Cr as main components or an element such as Pt or Ta added thereto. Perpendicular magnetic recording medium comprising an alloy thin film,
Use of a perpendicular magnetic recording medium composed of a multilayer thin film in which a Pt film or a Pd film and Co are alternately laminated at a constant cycle, an iron oxide-based magnetic thin film represented by barium ferrite, or a perpendicular magnetic recording medium composed of a magnetic coating layer. Can be. When recording is performed on these magnetic recording media, it is necessary to heat the magnetic recording medium to a temperature near its Curie temperature in a portion irradiated with irradiation light.

In general, the Curie temperature of a perpendicular magnetic recording medium as described above is as high as several hundred degrees Celsius or more, so that it is difficult to heat the film to the Curie temperature by irradiating the irradiation light to cause the disappearance of the magnetization in the irradiated portion. There are cases. Therefore, from the above viewpoint, it is necessary that the irradiation light has a sufficient power.

When a perpendicular magnetic recording medium composed of an amorphous alloy thin film mainly composed of a rare earth and a transition metal is used as the magnetic recording medium, it is possible to lower the erasing temperature of the DC erase magnetization 3 based on the DC erasing. It is more preferable because it is possible.

In particular, many amorphous alloy thin films mainly composed of heavy rare earths such as Gd (gadolinium), Tb (terbium), and Dy (dysprosium) and a transition metal are:
Since it has ferrimagnetism, magnetization can be eliminated at a compensation temperature sufficiently lower than the Curie temperature. By controlling the composition ratio of the rare earth element and the transition metal element, the compensation temperature can be controlled in a wide range as long as the performance of the perpendicular magnetic recording medium is not affected. Therefore, according to the example of the embodiment, by setting the compensation temperature of the magnetic recording medium to be slightly higher than the operating environment temperature of the magnetic recording / reproducing apparatus, it is possible to sufficiently use the irradiation light of relatively low power. Efficient preformat recording can be performed.

On the other hand, the magnetic recording method of the present invention will be described with reference to the sectional view of FIG. 5, taking the case of signal recording on an in-plane magnetic recording medium as an example.

First, as shown in FIG. 5A, a DC erasing magnetic field 2 is applied to the in-plane magnetic recording medium 1 to perform DC erasing uniformly in the film surface direction of the magnetic recording medium 1. As a result, a DC erase magnetization 3 is formed along the film surface direction.

Next, as shown in FIG. 5B, the photomask 4 is brought close to the surface of the DC-erased magnetic recording medium 1 so as not to come in contact with the magnetic recording medium 1 and irradiated with irradiation light 7. For the irradiation of the irradiation light 7, an ultraviolet light source or a laser light capable of uniformly irradiating parallel light over a large area can be used.

FIG. 5 shows an example in which the photomask 4 is brought close to the surface of the magnetic recording medium 1 so as not to come into contact with the surface. However, as in the example shown in FIG. It is also possible to adopt a configuration in which the mask 4 is brought into contact. In this case, since the surface of the magnetic recording medium and the photomask are in contact with each other, it is not possible to obtain an effect of preventing a medium surface defect or a signal drop due to a foreign substance interposed therebetween. However, the function of generating reversal magnetization, that is, the effect of sufficiently securing the recording performance, can be obtained for the future high coercivity magnetic recording medium as well as the configuration of FIG.

In the photomask 4, a mask pattern corresponding to an information signal array is formed by a metal mask film 6 on a nonmagnetic substrate 5 that can transmit the irradiation light 7. Since the irradiation light 7 cannot pass through the metal mask film 6,
Only in the portion where the metal mask film 6 is not formed,
The surface of the magnetic recording medium 1 is locally irradiated, and the surface of the magnetic recording medium can be heated in this portion.

When the surface of the magnetic recording medium is heated to, for example, the vicinity of the Curie temperature of the magnetic layer, the magnetization locally disappears at the heated portion. In this state, a DC bias magnetic field 10 having a polarity opposite to that of the DC erasing magnetic field 2 and the initial magnetization 3 ′ is applied,
When the irradiation light is cut off, the heated portion is gradually cooled naturally, and is magnetized in the process by the recording magnetic field 11 applied to the magnetic recording medium 1 based on the DC bias magnetic field 10 to the polarity opposite to the DC erase magnetization 3. You. As a result, in the magnetic recording medium 1, as shown in FIG. 5 (c), the initial magnetization 3 'and the reversal magnetization 9 based on the DC erasing are alternately arranged corresponding to the metal mask pattern formed on the photomask 4. Is recorded.

Unlike the recording method on the perpendicular magnetic recording medium illustrated in FIG. 3, in the recording method on the longitudinal magnetic recording medium, the floating magnetic field generated from the initial magnetization 3 ′ of the adjacent non-heated portion is heated. It cannot contribute to the recording of the reversal magnetization 9 in the portion. Therefore, in order to record an information signal array pattern in which the initial magnetization 3 'and the inversion magnetization 9 are alternately arranged, the application of the DC bias magnetic field 10 is essential.

As in the recording method for the perpendicular magnetic recording medium shown in FIG. 4, the magnitude of the DC bias magnetic field 10 must not be so large as to exceed the coercive force of the unheated portion. When a large DC bias magnetic field exceeding the coercive force of the non-heated portion is applied, the initial magnetization 3 ′ of the non-heated portion may be demagnetized or demagnetized. It is necessary to find the optimum value at a value smaller than the coercive force of

As a magnetic recording medium suitable for the magnetic recording method of the present embodiment shown in FIG. 5, an alloy thin film containing Co and Cr as main components or an alloy thin film obtained by adding an element such as Pt or Ta to them is used. In-plane magnetic recording medium, Co and S
In-plane magnetic recording medium composed of a granular thin film containing iO ₂ or Co, Pt and SiO ₂ as main components, iron oxide-based magnetic thin film represented by Co ferrite or in-plane magnetic recording medium composed of a magnetic coating layer, Co and O Or Co and Ni
And a magnetic recording medium composed of an obliquely deposited film containing O as a main component. When recording is performed on these magnetic recording media, it is necessary to heat the magnetic recording medium to a temperature near its Curie temperature in a portion irradiated with irradiation light.

Next, FIG. 6 shows an example of the external appearance (outlook) of a photomask having a mask pattern corresponding to the information signal array used in the magnetic recording method of the present invention. The photomask 4 illustrated in FIG. 6 is used for recording a preformat information signal such as a servo signal for tracking on a disk-shaped magnetic recording medium such as a hard disk, and has a square planar shape in FIG. Although shown, the photomask used in the magnetic recording method of the present invention is not limited to this, and a photomask having another planar shape such as a circle can be used.

On the surface of the photomask 4, a metal mask film 6 patterned according to an information signal array pattern recorded on a magnetic recording medium is formed. Since the photomask 4 illustrated in FIG. 6 is used for recording a preformat information signal such as a servo signal for tracking on a disk-shaped magnetic recording medium, the preformat information signal is provided at regular intervals in the circumferential direction of the disk. The arrangement pattern 12 is provided.

For the metal mask film 6, for example, a metal chromium film is used. The metal mask film 6 needs to have a sufficient thickness in consideration of the wavelength of the irradiation light and the transmittance of the metal mask film so as not to transmit the irradiation light in the portion where the metal mask film 6 is formed. On the other hand, the thickness of the metal mask film is smaller than the minimum unit of the information signal (in the case of a signal recorded on a magnetic disk medium, the recording bit length in the disk circumferential direction and the recording track width in the disk radial direction). If the value is larger than a certain value, the resolution at the time of recording may be reduced by scattered light, which is not preferable. Therefore, the thickness of the metal mask film 6 needs to be optimized based on experimental studies according to the example of the embodiment.

In one embodiment, the minimum unit of an information signal on a photomask using a chromium metal film as the metal mask film 6 is about 0.5 μm, and a perpendicular magnetic field for a hard disk using visible light or ultraviolet light is used. When recording was performed on a recording medium, the thickness of the metal chromium film was appropriately in the range of 200 nm to 400 nm.

The metal mask film 6 may be made of another metal film such as aluminum or copper or a metal alloy film depending on the embodiment, in addition to the above-described metal chromium film.
Since it is necessary to form a pattern corresponding to the information signal array using a lithography technique on this metal mask film, a resist pattern can be easily formed on this film, and further, by various etching methods. Preferably, it is easily removable.

[0111] In addition to the information signal array pattern 12, various patterns can be arranged on the photomask 4 according to the intended use. For example, in the photomask 4 illustrated in FIG. 4, an alignment marker 13 used for aligning the magnetic recording medium with the photomask is provided by the metal mask film 6. By using such an alignment marker 13, the center position between the information signal array pattern on the photomask and the magnetic recording medium is accurately aligned with reference to the center hole of a disk-shaped magnetic recording medium such as a hard disk. It becomes possible.

An example of the configuration of the information signal array pattern 12 formed on the photomask 4 in the region A shown in FIG. 6 is shown in the enlarged plan view of FIG. FIG. 7 shows an example of an information signal array pattern formed on a photomask in a region A, as a preformat information signal array pattern such as a tracking servo signal, an address information signal, and a clock signal recorded on a disk-shaped magnetic recording medium. The horizontal direction in the figure substantially coincides with the circumferential direction of the magnetic disk (that is, the recording track length direction), and the vertical direction substantially coincides with the radial direction of the magnetic disk (that is, the recording track width direction).

In the figure, the hatched portion is the portion where the metal mask film 6 is formed, and the irradiation light applied to the photomask 4 in this portion does not transmit and does not reach the magnetic recording medium. On the other hand, the white portion is a portion where the metal mask film 6 is not formed, and the irradiation light applied to the photomask passes through this portion and is applied to the surface of the magnetic recording medium.

The information signal array pattern shown in FIG. 7 is a set of rectangular patterns substantially parallel to the radial direction of the disk, and the length of each rectangular pattern in the radial direction of the disk is substantially the same as that of the prerecorded magnetic recording medium. Is formed so as to correspond to the recording track width of the magnetic disk drive device on which is mounted.

In the magnetic disk drive apparatus equipped with the magnetic disk medium on which the information signal array pattern of FIG. 7 is recorded by using the magnetic recording method of the present invention, when the magnetic head reproduces the tracking servo signal, The tracking servo operation can be performed by detecting a change in the amplitude of the reproduction signal due to the minute displacement.

Another example of the configuration of the information signal array pattern 12 formed on the photomask 4 in the region A shown in FIG. 6 is shown in the enlarged plan view of FIG. FIG. 8 shows an example of an information signal array pattern formed on the photomask in the area A, as in FIG. 7, such as a tracking servo signal, an address information signal, and a clock signal recorded on a disk-shaped magnetic recording medium. A preformat information signal array pattern is shown. The horizontal direction of the figure is the circumferential direction of the magnetic disk (that is, the recording track length direction).
The vertical direction substantially coincides with the radial direction of the magnetic disk (that is, the recording track width direction).

In the figure, the hatched portion is the portion where the metal mask film 6 is formed. In this portion, the irradiation light irradiated on the photomask does not pass and does not reach the magnetic recording medium. On the other hand, the white portion is the metal mask film 6
Irradiation light applied to the photomask in a portion where is not formed is transmitted through this portion to irradiate the surface of the magnetic recording medium.

While the information signal array pattern of FIG. 7 is a set of rectangular patterns substantially parallel to the disk radial direction, the information signal array pattern of FIG. 8 is non-parallel to the disk radial direction, In addition, it is formed so as to be a set of linear patterns that continuously cross a plurality of recording tracks in the disk radial direction.

In the magnetic disk drive apparatus equipped with the magnetic disk medium on which the information signal arrangement pattern of FIG. 8 is recorded by using the magnetic recording method of the present invention, when the magnetic head reproduces the tracking servo signal, the magnetic head in the disk radial direction The tracking servo operation can be performed by detecting a change in the reproduction signal phase due to the small displacement of the reproduction signal.

The information signal array pattern of the system for detecting the reproduction signal phase as illustrated in FIG. 8 has a larger disturbance than the information signal array pattern of the system for detecting the amplitude of the reproduction signal as illustrated in FIG. It has the advantages of being less susceptible to noise and enabling more accurate tracking servo.

However, in the preformat recording of a tracking servo signal or the like using a conventional magnetic head, the recording gap has a finite recording track width in the disk radial direction in the recording gap of the magnetic head, and also has a finite recording track width in the disk radial direction. On the other hand, there is a restriction that the information signal array pattern cannot have an arbitrary angle, and an information signal array pattern of a method of detecting a reproduction signal phase as illustrated in FIG. 8 cannot be recorded.

On the other hand, according to the recording method of the present invention, which is batch recording, the shape of the information signal array pattern recorded on the magnetic disk medium can be freely realized on the photomask. It is extremely easy to record an information signal array pattern of a method of detecting a reproduction signal phase or a linear pattern continuously traversing a recording track in the radial direction of a disc, as exemplified in (1).

Next, an irradiation method of irradiation light in the magnetic recording method according to the embodiment of the present invention will be described with reference to FIGS.

FIG. 9 is a sectional view showing an example of a configuration of a method of irradiating irradiation light in the magnetic recording method according to the embodiment of the present invention. In the configuration of FIG. 9, the irradiation light 7 emitted from the lamp light source 14 is uniformly irradiated over the entire surface of the photomask 4. Irradiation light 7 applied to the photomask 4 partially transmits through the photomask 4 according to the pattern shape of the metal mask film formed on the photomask 4,
It is projected on the surface of the magnetic recording medium 1. Here, the irradiation light 7 transmitted through the photomask 4 is accurately transferred to the photomask 4.
To project the above pattern on the surface of the magnetic recording medium,
It is preferable that the irradiation light 7 is uniformly and vertically incident on the photomask surface. When the irradiation light is obliquely incident on the photomask from a random direction, the recording resolution may be reduced due to the scattered light due to the oblique incidence. From such a viewpoint, it is preferable that the lamp light source 14 be capable of emitting parallel light perpendicularly incident on the photomask surface.

The minimum unit of an information signal that can be recorded on a magnetic recording medium using the magnetic recording method of the present invention (in the case of a signal recorded on a magnetic disk medium, the recording bit length in the disk circumferential direction, The recording track width in the radial direction of the disc) is determined (constrained) by the wavelength of the irradiation light 7.
For example, even if an information signal array pattern having a line width of 1.0 μm is formed on a photomask, the irradiation light 7 has a wavelength of 1.5 μm.
In the case of infrared light of about μm, it is difficult to record a signal pattern having a line width of 1.0 μm on the magnetic recording medium 1. From such a viewpoint, it is preferable that the wavelength of the irradiation light 7 emitted from the lamp light source 14 is short. For example, when the minimum unit of the information signal to be recorded is about 0.5 μm, it is preferable to use an ultraviolet lamp as the lamp light source 14.

On the other hand, as shown in FIG.
Is used to uniformly irradiate the irradiation light 7 over the entire surface of the photomask 4, the power of the lamp light source is distributed and applied to the photomask surface. Depending on the area and the magnetic characteristics of the magnetic recording medium 1, it may be difficult to sufficiently heat the irradiated portion to cause the magnetization to disappear.

In such a case, as shown in FIG. 10, the recording is partially performed by using the laser light source 15, and further, the laser light is scanned along the surface of the photomask 4 to perform the magnetic recording. A configuration in which preformat recording over the entire surface of the medium 1 is completed may be adopted.

In this case, since it is not possible to perform batch recording over the entire surface of the magnetic recording medium, productivity related to preformat recording is slightly sacrificed as compared with the configuration shown in FIG.

However, compared with the minimum recording unit (bit area of a signal recorded on a magnetic disk medium) in linear recording using a conventional magnetic head, the spot size of a laser beam is increased to at least ¹⁰⁸ times or more. Therefore, compared to the preformat recording using the conventional magnetic head, there is still a great advantage in terms of productivity.

Now, in the magnetic recording method of the present invention,
By shortening the wavelength of the irradiation light 7, a finer and higher-density information signal pattern can be recorded. For example, when deep ultraviolet light having a wavelength of 0.25 μm is used as the irradiation light 7, a high-density signal having a bit length of about 0.25 μm can be recorded in principle.

However, it is sometimes difficult to form such a fine metal mask pattern on a photomask using the current technology. Alternatively, even if it is technically possible, the manufacturing cost of the photomask may become enormous, and the cost advantage of the preformat recording may be sacrificed to some extent.

When a fine signal pattern as described above, that is, a high-density signal pattern is recorded, the lens 16 is placed between the photomask 4 and the magnetic recording medium 1 as illustrated in FIGS. By refracting the irradiating light 7 through the mask, the mask pattern corresponding to the information signal array provided on the photomask 4 can be reduced and projected on the surface of the magnetic recording medium 1.

For example, if the mask pattern provided on the photomask 4 is projected by the lens 16 on the surface of the magnetic recording medium 1 in a reduced size of ５, the mask pattern is recorded on the magnetic recording medium 1. Bit length of the information signal is 0.
Even when the value is as small as 25 μm, the mask pattern corresponding to this information signal array is 1.25 μm (=
It may be provided on the photomask 4 with a relatively large size of 0.25 × 5). This makes it easy to manufacture the photomask and reduces the manufacturing cost.

As described above, an example of the embodiment of the present invention has been described. However, the configuration of the present invention can be applied to various embodiments. For example, in the specification of the present application, the description has been made mainly on application to a magnetic disk medium mounted on a hard disk drive or the like, but the present invention is not limited to this, and a flexible magnetic disk, a magnetic card Also, the present invention can be applied to a magnetic recording medium such as a magnetic tape, and the effects of the invention can be obtained in the same manner as described above.

In the above description, the information signal recorded on the magnetic recording medium has been described with a focus on the preformat information signal such as the servo signal for tracking, the address information signal, and the clock signal. The information signal to which the configuration described above can be applied is not limited to the above.
For example, it is possible in principle to record various data signals, audio and video signals using the configuration of the present invention. In this case, the master information carrier of the present invention and the recording technology on the magnetic recording medium using the master information carrier enable mass production of soft disk media to be produced and can be provided at low cost.

[0136]

As described above, according to the present invention, while the excellent productivity and the recording accuracy are ensured due to the static batch recording, once magnetization based on active heating by light irradiation is achieved. Because of the loss, the function of generating reversal magnetization is sufficiently secured while avoiding the problems of spacing loss and non-uniform magnetization, and in addition, the contact of the photomask from the surface of the magnetic recording medium is ensured, High reliability can be achieved without having to wait for a certifying test while avoiding the problem of signal loss or head crash due to the foreign matter causing the problem.

That is, according to the present invention, in recording a preformat information signal such as a servo signal for tracking, an address information signal, and a clock signal on a magnetic recording medium, the recording accuracy of the preformat information signal is excellent and the productivity is high. And a magnetic recording method excellent in reliability. As a result, it is possible to supply a magnetic recording / reproducing device capable of high-density and large-capacity recording, particularly a magnetic disk drive device represented by a hard disk drive, inexpensively and in large quantities.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a configuration example of a magnetic recording method according to an embodiment of the present invention;

FIG. 2 is an enlarged sectional view showing another configuration example of the magnetic recording method according to the embodiment of the present invention;

FIG. 3 is an enlarged sectional view showing another configuration example of the magnetic recording method according to the embodiment of the present invention;

FIG. 4 is an enlarged sectional view showing another configuration example of the magnetic recording method according to the embodiment of the present invention;

FIG. 5 is an enlarged sectional view showing still another configuration example of the magnetic recording method according to the embodiment of the present invention;

FIG. 6 is a plan view showing a configuration example of a photomask used in the magnetic recording method according to the embodiment of the present invention.

FIG. 7 is an enlarged plan view showing one configuration example of an information signal array pattern on a photomask used in the magnetic recording method according to the embodiment of the present invention;

FIG. 8 is an enlarged plan view showing another configuration example of the information signal array pattern on the photomask used in the magnetic recording method according to the embodiment of the present invention;

FIG. 9 is a sectional view showing a configuration example of an irradiation method of irradiation light in the magnetic recording method according to the embodiment of the present invention.

FIG. 10 is a sectional view showing another configuration example of the irradiation method of the irradiation light in the magnetic recording method according to the embodiment of the present invention;

FIG. 11 is a sectional view showing still another configuration example of the irradiation method of the irradiation light in the magnetic recording method according to the embodiment of the present invention.

FIG. 12 is a sectional view showing still another configuration example of the irradiation method of the irradiation light in the magnetic recording method according to the embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic recording medium 2 DC erasing magnetic field 3 DC erasing magnetization 3 'Initial magnetization based on DC erasing 4 Photomask 5 Non-magnetic substrate 6 Metal mask film 7 Irradiation light 8 Floating magnetic field 9 Inversion magnetization 10 DC bias magnetic field 11 Recording magnetic field 12 Preformat Information signal array pattern 13 Alignment marker 14 Lamp light source 15 Laser light source 16 Lens

 ──────────────────────────────────────────────────の Continuing on the front page (72) Keizo Miyata 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Kaoru Matsuoka 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 5D091 AA08 BB07 CC17 CC26 HH20 5D112 DD02 GA19

Claims (9)

[Claims] 1. A photomask having a mask pattern corresponding to an information signal arrangement is disposed in contact with a surface of a magnetic recording medium which has been DC-erased in advance in a contact state, and is disposed on the surface of the magnetic recording medium via the photomask. Magnetically recording a recording magnetization pattern corresponding to the information signal array on the surface of the magnetic recording medium by locally heating an irradiated portion of the surface of the magnetic recording medium with the irradiated light energy; Recording method. 2. A photomask having a mask pattern corresponding to an information signal arrangement is arranged in a non-contact state with respect to a surface of a magnetic recording medium which has been DC-erased in advance, and the surface of the magnetic recording medium is interposed via the photomask. Locally heating an irradiated portion of the surface of the magnetic recording medium with the light energy applied to the magnetic recording medium, thereby thermomagnetically recording a recording magnetization pattern corresponding to the information signal array on the surface of the magnetic recording medium. Magnetic recording method. 3. The method according to claim 1, wherein the step of locally heating the irradiated portion of the surface of the magnetic recording medium includes applying a DC bias magnetic field having a polarity opposite to the initial magnetization of the magnetic recording medium by DC erasing. 3. The magnetic recording method according to 1 or 2. 4. The method according to claim 1, wherein in applying the DC bias magnetic field,
4. The magnetic recording method according to claim 3, wherein a DC bias magnetic field smaller than a coercive force in an unheated region of the magnetic recording medium is applied. 5. The thermomagnetic recording is performed on a perpendicular magnetic recording medium whose magnetic layer has an axis of easy magnetization in a direction normal to the surface of the magnetic layer as the magnetic recording medium. The magnetic recording method according to any one of claims 1 to 4. 6. The magnetic recording medium according to claim 1, wherein the magnetic layer is made of an amorphous metal alloy having ferrimagnetism with a rare earth element and a transition metal as main components, and locally irradiating a portion to be irradiated on the surface of the magnetic recording medium. 6. The magnetic recording method according to claim 5, wherein, when heating is performed, the irradiated portion is heated to near a compensation temperature of the magnetic layer. 7. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is heated by irradiating the magnetic recording medium with parallel light that is collectively applied to the entire surface of the photomask. The magnetic recording method according to any one of the above. 8. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is heated by irradiating the magnetic recording medium with a laser beam that is scanned along a surface of the photomask. Magnetic recording method. 9. An information signal array on the photomask by interposing a lens between the photomask and the magnetic recording medium disposed opposite to each other, and refracting irradiation light through the lens. 9. The magnetic recording method according to claim 2, wherein the corresponding mask pattern is reduced and projected onto the surface of the magnetic recording medium.