JP3363852B2 - Manufacturing method of magnetic recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master information carrier for recording information signals on a large capacity, high recording density magnetic recording medium used in a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art At present, a magnetic recording / reproducing apparatus tends to have a higher recording density in order to realize a smaller size and a larger capacity. In the field of hard disk drives, which are typical magnetic recording media, the areal recording density is already about 1.55.
Devices exceeding Gbit / cm ² (10 Gbit / in ² ) have been commercialized, and will be about 3.1 to 6.2 G in a few years.
It is recognized that the technological progress is so rapid that the practical application of bit / cm ² (20-40 Gbit / in ² ) is discussed.

The technical background of enabling such high recording density is to improve medium performance, read head / disk interface performance, and low output by adopting a new signal processing method such as partial response. There are improvements in signal reading performance.

However, in recent years, the increasing tendency of the track density greatly exceeds the increasing tendency of the linear recording density, which is a main factor for the improvement of the areal recording density. This is because a magnetoresistive element type head, which has far better reproduction output performance than the conventional induction type magnetic head, has been put into practical use. At present, due to the practical use of the magnetoresistive element type head, a track width signal of only a few μm can be transmitted with an SN ratio (Signal Noise ratio
io) It is possible to reproduce well. 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.

The head tracking servo technique plays an important role in order for the head to accurately scan a track which is continuously narrowing and reproduce a signal with a good SN ratio. Regarding such tracking servo technology, for example, “Yamaguchi: High-precision servo technology for magnetic disk devices, Journal of Japan Society for Applied Magnetics, Vol. 20, No. 3, pp. 77.
1, (1996) ”. According to the above-mentioned literature, in the present hard disk drive, tracking servo is performed at a constant angular interval in one round of the disk, that is, in 360 degrees. An area in which signals, address information signals, reproduced clock signals, and the like are recorded (hereinafter, referred to as “preformatted signal” and recording preformatted signal is referred to as “preformat recording”) is provided. By reproducing these signals at regular intervals, the magnetic head can accurately scan the track while confirming and correcting the position of the head.

Since the above-mentioned tracking servo signal, address information signal, reproduction clock signal, etc. serve as reference signals for the head to accurately scan the track,
At the time of recording, accurate positioning accuracy is required. For example, “Uematsu, et al .: Current status and prospects of mechanical servo, HDI technology, Material of 9th Research Meeting of Japan Society for Applied Magnetics, 93-5, pp.35.
According to the contents described in (1996) ”, in the present hard disk drive, after the disk is incorporated into the drive, preformat recording is performed by a magnetic head whose position is strictly controlled using a dedicated servo recording device. .

The recording of the servo signal, the address information signal, and the pre-formatted signal of the reproduction clock signal as described above is the same in the commercially available large-capacity flexible disk and the removable hard disk medium in which the disk cartridge is detachable. In addition, a magnetic head is used by using a dedicated servo recording device.

Since preformat recording using a dedicated servo recording device is performed in serial operation for each track of the magnetic head, it takes several hours to perform preformat recording on one magnetic recording medium. However, this is a major obstacle to improvement in productivity, which in turn leads to an increase in production cost of the magnetic recording medium.

The time hindrance for preformat recording becomes more serious as the track density of the magnetic recording medium increases. This is not only due to an increase in the number of tracks in the disk radial direction. The recording interval of pre-format recording required for accurate positioning of the head is not determined by the physical distance on the track on which the head moves, but is determined by the amount of information read by the header. Every time the amount information is read, information such as a servo signal by preformat recording is required.

Therefore, the higher the track density, the narrower the physical interval on the track where a certain amount of information that requires head positioning is recorded. For this reason, it is necessary to narrow the angular interval for providing the servo area in which the tracking servo signal and the like are recorded in one round of the disk, that is, in 360 degrees.

As described above, the higher the recording density of the magnetic recording medium, the larger the amount of signal to be preformatted on the disk, and the more time is required for preformatted recording.

In the pre-format recording method in which the head is operated serially for each track, the problem that the recording time becomes long cannot be solved by any method. Therefore, in the future, it is considered that the magnetic transfer technology will be used to shift to the pre-format recording method by surface contact. This pre-format recording method by surface contact uses a master information carrier in which a ferromagnetic thin film is deposited in a pattern corresponding to an information signal array such as a servo signal on the surface of a non-magnetic substrate formed of a non-magnetic material. Information signals such as servo signals on the master information carrier are recorded on the magnetic recording medium by bringing the ferromagnetic thin film of the information carrier into close contact with the magnetic recording medium for preformat recording and magnetizing the ferromagnetic thin film. The preformat recording method based on this surface contact is described in detail in Japanese Patent Laid-Open No. 10-40544. A technique for achieving good adhesion between the master information carrier and the magnetic recording medium is disclosed in Japanese Patent Laid-Open No. 10-269566.

[0013]

However, JP-A-10-
40544 and JP-A-10-269566.
The pre-format recording method for transferring and recording by surface contact as disclosed in Japanese Patent Laid-Open No. 2004-96242 has not yet solved the following problems.

In the pre-format recording method of transfer recording, when the pre-format signal is recorded on the magnetic recording medium by using the master information carrier, the magnetic recording medium and the ferromagnetic thin film provided on the surface of the master information carrier are compressed and compressed. Wear
After the preformat recording is completed, the ferromagnetic thin film is separated from the magnetic recording medium. Since the magnetic recording medium and the ferromagnetic thin film are brought into close contact with each other with a large force under pressure, a large attraction force is generated between the magnetic recording medium and the ferromagnetic thin film when the ferromagnetic thin film is separated from the magnetic recording medium. Therefore, the force of separating the ferromagnetic thin film from the magnetic recording medium acts as the force of separating the ferromagnetic thin film from the non-magnetic substrate. Since the force for peeling the ferromagnetic thin film from the non-magnetic substrate is applied between the non-magnetic substrate and the ferromagnetic thin film every time the pre-format recording operation is repeated, the non-magnetic substrate of the master information carrier can be repeated by repeating the pre-format recording. The ferromagnetic thin film peels off from the surface. The problem is that as the recording density of the magnetic recording medium increases, not only the individual ferromagnetic thin films become smaller, but also the contact area with the non-magnetic substrate becomes smaller and the adhesion of the ferromagnetic thin film to the substrate becomes smaller. The higher the recording density of the magnetic recording medium, the more serious it becomes.

If the peeling of the ferromagnetic thin film easily occurs, not only the preformat signal transferred to the magnetic recording medium becomes defective, but also the number of disks of the magnetic recording medium capable of preformat recording by one master information carrier. This leads to a decrease in productivity, which leads to a high cost of the magnetic recording medium.

If the attraction force generated between the master information carrier and the magnetic recording medium is large, a large force is required to separate the magnetic recording medium from the master information carrier, and the stroke of the movement for separating the magnetic recording medium is also large. Become longer,
Since it takes extra time accordingly, the cost becomes higher.

The present invention has been made to solve such a problem, and reduces the attraction force generated between a non-magnetic substrate or a ferromagnetic material and a magnetic recording medium at the time of preformat recording to reduce the non-magnetic property. It is an object of the present invention to provide a master information carrier capable of suppressing peeling of a ferromagnetic material from a substrate, improving reliability and durability, and shortening time spent for preformat recording.

[0018]

A master information carrier of the present invention comprises a non-magnetic substrate formed of a non-magnetic material, and a plurality of ferromagnetic portions having a ferromagnetic material deposited on the first surface of the non-magnetic substrate. The plurality of ferromagnetic portions form a shape pattern of a signal array, and each ferromagnetic portion whose surface is brought into close contact with or close to the magnetic recording medium is magnetized to generate an information signal corresponding to the signal array. A master information carrier for recording on the magnetic recording medium, wherein the ferromagnetic portion has a second surface facing the magnetic recording medium, and the magnetic recording medium has a third surface facing the ferromagnetic portion. The center line average roughness of at least one of the first surface and the second surface, and the third surface
The center line average roughness of the surface is different, which solves the above-mentioned problems.

Each of the ferromagnetic portions may protrude from the surface of the non-magnetic substrate, and the center line average roughness of the second surface may be larger than the center line average roughness of the third surface.

The non-magnetic substrate has a recess formed in the first surface, the ferromagnetic portion is deposited inside the recess, and the center line average roughness of the first surface is the third surface. It may be larger than the center line average roughness of the surface.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a schematic diagram of a master information carrier for a hard disk according to a first embodiment of the present invention. As shown in this figure, the master information carrier 1 according to the first embodiment of the present invention comprises a non-magnetic substrate 2 formed of a non-magnetic material in a disk shape,
A servo signal for tracking, which is preformatted and recorded on a hard disk which is a magnetic recording medium, has a plurality of signal areas 3 ... 3 formed of a ferromagnetic material.

When the read header is used to read the hard disk to be preformatted, a preformatted tracking servo signal or the like is required to confirm the position of the header each time a certain amount of information is read. Become. The recording capacity of each track of the hard hard disk is the same, and the recording density of the track is higher toward the center of the disk. The target interval becomes narrow. Therefore, the track interval between the signal areas 3 of the master information carrier 1 that performs preformat recording on the hard disk also becomes narrower from the outer peripheral side toward the central side. It should be noted that the actual master information carrier is provided with a marker or the like for positioning with respect to the hard disk, but it is omitted in FIG.

FIG. 2 shows the area A of the signal area 3 in FIG.
It is an enlarged view of the range of. As shown in this figure, a pre-formatted signal for pre-formatted recording on the hard disk is formed by the ferromagnetic material 4 between the portions of the non-magnetic substrate 1 corresponding to the data area of the hard disk. The preformat signal includes an address information signal and a clock signal in addition to the tracking servo signal. Silicon (Si) can be applied as the material of the non-magnetic substrate 2, and cobalt (Co) can be applied as the material of the ferromagnetic material 4.

FIG. 3 shows a cross section taken along the line BB of FIG. As shown in this figure, the preformatted signal is formed by a thin film in which the ferromagnetic material 4 is deposited in the recess 5 provided in the non-magnetic substrate 2. The recess 5 has a depth of about 500 nm and a width of about 800 to about 200.
The thickness of the ferromagnetic material 4 is preferably about 0 nm from the surface 2a of the nonmagnetic substrate 2 in the recess 5 as described above.
˜100 nm is deposited so as to project.

As a method for depositing the ferromagnetic material 4 in the recess 5, a general thin film forming method which has been conventionally used, such as a sputtering method, a vacuum vapor deposition method, an ion plating method, a CVD method or a plating method is used. You can When the ferromagnetic material 4 is deposited by these methods, the film forming conditions are adjusted so that the roughness of the surface 4a of the ferromagnetic material 4 is the center line average roughness (also called "arithmetic average roughness"). R (a)
To be 1.1 nm.

As one of such film forming conditions, there is a method of forming fine unevenness on the bottom surface 5a of the recess 5 in which the ferromagnetic material 4 is deposited in advance. When the ferromagnetic material 4 is deposited on the bottom surface 5a having fine unevenness, the unevenness corresponding to the unevenness of the bottom surface 5a is also formed on the surface 4a of the ferromagnetic material 4 after film formation. In addition, as a method of increasing the center line average roughness of the surface 4a of the ferromagnetic material 4, there is a method of directly roughening the surface 4a by wet etching, dry etching, or the like. Furthermore, the surface 4 of the ferromagnetic material 4 is formed by using a slurry that is mixed so as not to affect the constituent material of the non-magnetic substrate 2 but only the constituent material of the ferromagnetic material 4.
There is also a method of polishing a.

The roughness of the surface 4a of the ferromagnetic material 4 of the master information carrier 1 is 1.1 nm as the centerline average roughness R (a), while preformat recording is performed as shown in FIG. Hard disk 100 as a known magnetic recording medium
Surface 100a has a center line average roughness R (a) of 0.8n.
m, which are different from each other in centerline average roughness.

Here, the center line average roughness is a quantity representing the roughness of the surface of the object to be measured, which is defined by the JIS standard.
It is given by the mathematical formula shown in Formula 1.

[0029]

[Equation 1]

In Equation 1, L is the measurement length, y (x)
Indicates the two-dimensional profile (cross-sectional curve) to be measured. y (x) is an atomic force microscope (AFM),
It can be measured by various methods such as a scanning tunneling microscope (STM). The numerical value of the centerline average roughness described in the present specification is the average of R (a) observed in the tapping mode using an Si cantilever with a relatively small tip curvature radius of the probe by AFM at any 10 points. It is a value. The measurement length L was 2 μm. Also,
As the AFM probe, a commercially available probe with a tip radius of curvature of 50 nm or less is desirable.

As described above, in the master information carrier 1 according to the first embodiment of the present invention, the ferromagnetic material 4 is the non-magnetic substrate 2.
Of the ferromagnetic material 4 protruding from the surface 2a of the
The center line average roughness R (a) of a is larger than the center line average roughness R (a) of the surface 100a of the hard disk 100 as a magnetic recording medium. According to the master information carrier 1 having such a configuration, as shown in FIG. 5, the contact area between the surface 100a of the hard disk 100 and the surface 4a of the ferromagnetic material 4 is small, so that the surface 100a of the hard disk 100 and the ferromagnetic material 4 are ferromagnetic. Surface 4a of material 4
The attraction force generated between and is also small, and the force for separating the master information carrier 1 from the hard disk 100 can be small. Therefore, peeling of the ferromagnetic material 4 from the non-magnetic substrate 2 can be suppressed. In FIG. 5, the shaded area is an adsorbate C such as water vapor in the atmosphere adsorbed on the contact surface between the surface 4a of the ferromagnetic material 4 and the surface 100a of the hard disk 100. 4 and the hard disk 100 cause a large attraction force.

In order to confirm the above effects, the following experiment was conducted.

A master information carrier for comparative experiments as shown in FIG. 6 is manufactured by using the same method as the method for manufacturing the master information carrier 1 shown in FIG. 3 (hereinafter referred to as "master information carrier 10"). . Master information carrier for comparative experiments 1
0 indicates that only the center line average roughness R (a) of the surface 14a of the ferromagnetic material 14 deposited in the recess 5 as shown in FIG.
It is different from the master information carrier 1. The center line average roughness R (a) of the surface 14a of the ferromagnetic material 14 of the master information carrier 10 for comparison experiment is 0.9 nm.

Further, as shown in FIG. 7, the hard disk 101 for preformat recording using the master information carrier 10 for the comparative experiment has a center line average roughness R (a) of the surface 101a in contact with the ferromagnetic material 14. ) Is 0.9 nm. Therefore, regarding the master information carrier 10 for comparison experiments, the center line average roughness R between the surface 14a of the ferromagnetic material 14 and the surface 101a of the hard disk 101 is measured.
(A) is equal. Therefore, as shown in FIG. 8, the surface 14 a of the ferromagnetic material 14 and the surface 1 of the hard disk 101 are
The contact area with 01a is larger than in the case of the master information carrier 1 according to the first embodiment of the present invention (see FIG. 5).

Thus, the surface 14a of the ferromagnetic material 14 is
And the surface 101a of the hard disk 101 have the same centerline average roughness R (a).
It can be confirmed that the master information carrier 1 suppresses the peeling of the ferromagnetic material 4 from the non-magnetic substrate 2 by continuously transferring the preformatted signal.

Details of the continuous transfer method are described in JP-A-10-2.
This method is also followed in the present embodiment. The outline of the continuous transfer method described in this publication is as follows. The recording surface of the hard disk for recording the preformatted signal is brought into close contact with the master information carrier, and the air between the master information carrier and the hard disk is exhausted to form a vacuum, thereby bringing them into close contact with each other. By applying a magnetic field to the master information carrier closely attached to the hard disk, the ferromagnetic material 4 is magnetized, and the signal pattern formed by the plurality of magnetized ferromagnetic materials 4 is recorded on the hard disk as a preformatted signal.

According to the above-mentioned method, the master information carrier 1 and the comparative master information carrier 10 are each set to 1
Ten thousand continuous transfer experiments were performed.

As a result, in the comparative master information carrier 10 for comparison, the center line average roughness R (a) of the surface 14a of the ferromagnetic material 14 and the surface 101a of the hard disk 101 are equal, the ferromagnetic material 14 is a non-magnetic substrate. Many areas were peeled from No. 2.

On the other hand, the center line average roughness R between the surface 4a of the ferromagnetic material 4 and the surface 100a of the hard disk 100.
In the master information carrier 1 of the first embodiment of the present invention in which (a) is different, peeling of the ferromagnetic material 4 from the non-magnetic substrate 2 was not seen.

The hard disk 100 for preformat recording on the master information carrier 1 has a center line average roughness R (a) of 0.8 nm on the surface 100a, and the surface 101a (R (a) of the hard disk 101 used in the comparative experiment. Is 0.
9 nm), the surface 100a is flatter, and if the surface roughness of the ferromagnetic material is equal, a larger centering force is generated than the surface 101a of the hard disk 101. Nevertheless, the master information carrier 1 according to the first embodiment of the present invention
In No. 2, no peeling of the ferromagnetic material 4 from the non-magnetic substrate 2 is observed, so it can be confirmed that the configuration of the present invention produces a remarkable effect.

As shown in FIG. 9, when the master information carrier 10 for comparative experiments is separated from the hard disk 101, a large force is required to adsorb the adsorbate C such as water vapor in the atmosphere over a wide area. And the magnitude of the force was about 9.8 N / cm ² (1.0 kgf / cm ² ). On the other hand, the force required to separate the master information carrier 1 according to the first embodiment of the present invention from the hard disk 100 is about half, about 4.9 N / cm ² (0.5
kgf / cm ² ).

As described above, the master information carrier 1 of the first embodiment of the present invention is more durable than the conventional master information carrier with respect to the number of times of continuous transfer, and one master information carrier 1 has more durability. Not only can be continuously transferred to the magnetic recording medium, but the force required for separating the magnetic recording medium from the master information carrier 1 can be small,
Since the stroke of the movement for separating is also shortened, the time required for continuous transfer can be reduced and the production cost of a magnetic recording medium such as a hard disk can be reduced.

Also, the quality of the reproduced signal of the pre-formatted signals of the hard disk 100 pre-formatted by using the master information carrier 1 and the hard disk 101a pre-formatted by the master information carrier 10 for comparison experiment. As a result of evaluation, the hard disk 100 preformatted by the master information carrier 1 according to the first embodiment of the present invention is
It was possible to reproduce a preformatted signal having a high S / N ratio. In addition, MFM (Magnetic Force)
Microscope) was used to compare the magnetization transitions at the boundaries of the tracks preformatted and recorded on the hard disk. As a result, the hard disk 100 preformatted and recorded by the master information carrier 1 according to the first embodiment of the present invention was compared. It was confirmed that the steeper magnetic transition was better and a sharper magnetic signal was formed.

(Second Embodiment) The configuration outline of a master information carrier (hereinafter referred to as "master information carrier 7") in the second embodiment is shown in FIG. 1 described in the first embodiment. The configuration is the same as that shown in FIG. The master information carrier 7 is the master information carrier 1 of the first embodiment.
10 is that, as shown in FIG. 10, the ferromagnetic material 6 is deposited inside the recess 5 provided in the non-magnetic substrate 8, and the surface 8a of the non-magnetic substrate 8 is intentionally roughened. This is the point to finish. As the material forming the non-magnetic substrate 8 and the ferromagnetic material 6, silicon (Si) and cobalt (Co) can be applied as in the first embodiment.

The structure of the master information carrier 7 shown in FIG. 10 is manufactured by the following procedure. First, the recess 5 is formed in the non-magnetic substrate 8 by dry etching.

Next, the sputtering method, the vacuum vapor deposition method,
Using the ion plating method, the CVD method, the plating method or the like, the ferromagnetic material 6 is provided inside the recess 5, that is, the upper surface of the ferromagnetic material 6 is below the upper end of the recess 5.
Is deposited to form a thin film.

Next, the surface of the non-magnetic substrate 8 is polished with a slurry that is mixed so as not to affect the constituent material of the ferromagnetic material 6 but only the constituent material of the non-magnetic substrate 8. Center line average roughness R (a) to 1.1 nm. Even after the polishing process, the upper surface of the ferromagnetic material 6 is below the upper end of the recess 5.

Master information carrier 7 formed in this way
It is the same hard disk 100 as the magnetic recording medium used in the first embodiment that performs pre-format recording using. Surface 100 of this hard disk 100
The center line average roughness R (a) of a was 0.8 nm.

Therefore, in the master information carrier 7 according to the second embodiment of the present invention, the center line average roughness R (a) of the surface 8a of the non-magnetic substrate 8 is the surface 100a of the hard disk 100 as a magnetic recording medium. The center line average roughness R (a) is larger than the center line average roughness R (a).

The master information carrier 7 configured in this way
According to the method, the ferromagnetic material 6 is used for preformat recording.
Does not come into direct contact with the hard disk, there is no risk of the ferromagnetic material 6 peeling from the non-magnetic substrate 8. Further, the surface 100a of the hard disk 100 and the non-magnetic material
Since the contact area between the surface 8a of the hard disk 100 and the surface 8a of the non-magnetic material 8 is small.
The attraction force generated between and is also small, and the force for separating the master information carrier 1 from the hard disk 100 can be small. Therefore, since the stroke of the movement for separating is shortened, the time required for continuous transfer of the preformat signal is reduced.

The following experiment was conducted to confirm the above effect.

A master information carrier for comparative experiments as shown in FIG. 11 is manufactured by using the same method as the method for manufacturing the master information carrier 7 shown in FIG. 10 (hereinafter referred to as "master information carrier 20"). . As shown in FIG. 11, the master information carrier 10 for comparison experiments is different from the master information carrier 7 only in the center line average roughness R (a) of the surface 18 a of the non-magnetic substrate 18. The center line average roughness R (a) of the surface 18a of the non-magnetic substrate 18 of the master information carrier 20 for comparative experiments is 0.9 nm.

Further, the master information carrier 20 for comparison experiments
The magnetic recording medium for pre-format recording using
Hard disk 1 used in the comparative experiment of the first embodiment
01, and the center line average roughness R (a) of the surface 101a in contact with the surface 18a of the nonmagnetic substrate 18 is 0.9 nm. Therefore, in the comparative experiment, the center line average roughness R (a) of the surface 18a of the non-magnetic substrate 18 and the surface 101a of the hard disk 101 are equal.

Thus, the surface 18a of the non-magnetic substrate 18 is
And the surface 101a of the hard disk 101 have the same centerline average roughness R (a).
It can be confirmed that the master information carrier 7 reduces the attraction force generated between the master information carrier 7 and the hard disk as the magnetic recording medium by carrying out the transfer test of the pre-formatted signal.

As the transfer method, the method described in JP-A-10-269566 is used as in the first embodiment. By this method, transfer experiments were carried out for the master information carrier 7 and the comparative master information carrier 20.

As a result, after pre-format recording, in order to separate the surface 18a of the non-magnetic substrate 18 of the master information carrier 20 for comparative experiments from the surface 101a of the hard disk 101, about 9.8 N / cm ² (1.0 kgf / 1.0 kgf / c
m ² ) of force was required. On the other hand, the second aspect of the present invention
The force for separating the surface 8a of the non-magnetic substrate 8 of the master information carrier 7 of the embodiment from the surface 100a of the hard disk 100 is about 4.9 N / cm ² (0.5 kgf /
cm ² ), which is about half that of the master information carrier 20 for comparative experiments.

As described above, in the master information carrier 7 according to the second embodiment of the present invention, the ferromagnetic material 6 does not directly contact the magnetic recording medium such as a hard disk, so that the ferromagnetic material 6 is not Since there is no danger of peeling from the magnetic substrate 18, the durability against continuous transfer is high, and the production cost of a magnetic recording medium such as a hard disk can be reduced. Further, since the force required to separate the magnetic recording medium from the master information carrier 7 is small and the stroke of the motion for separating the magnetic recording medium is short, the time required for continuous transfer is reduced and the production cost of the magnetic recording medium is further increased. It can be reduced.

The embodiments of the present invention are not limited to those described above, but can be implemented with various modifications. For example, in the first embodiment, the attraction between the surface of the magnetic recording medium and the surface of the ferromagnetic material is reduced to prevent the ferromagnetic material from peeling off from the non-magnetic substrate. The contact area between the non-magnetic substrate and the ferromagnetic material may be increased to strengthen the coupling force between the non-magnetic substrate and the ferromagnetic material.

Further, in the first and second embodiments,
The centerline average roughness of the surface of the ferromagnetic material or the surface of the non-magnetic substrate is made larger than the centerline average roughness of the surface of the hard disk as the magnetic recording medium. The line average roughness may be increased.

Furthermore, in the above-mentioned embodiment, the description has been given mainly focusing on the disk-shaped magnetic recording medium.
It can be applied to a magnetic recording medium such as a magnetic card or a magnetic tape, and the same remarkable effects as described above can be obtained.

Regarding the information signals preformatted and recorded on the magnetic recording medium, description has been made focusing on preformatted signals such as tracking servo signals, address information signals, and reproduction clock signals. However, the information signal that can be recorded by the configuration of the present invention is not limited to the above, and various data signals, audio and video signals can be recorded. In this case, the master information carrier of the present invention and the recording method for the magnetic recording medium using the master information carrier enable efficient mass production of the soft disk medium, which can be provided at a low cost. is there.

It goes without saying that the various forms of application of the present invention as described above belong to the category of the present invention together with the forms of various configurations modified according to their characteristics.

[0063]

According to the master information carrier of the present invention, peeling of a ferromagnetic material forming a preformatted signal on a non-magnetic substrate is prevented, and the effect of suppressing peeling is dramatically enhanced. The life of the information carrier for continuous use is extended, and one master information carrier can perform continuous transfer of preformatted signals to more magnetic recording media, thus reducing the production cost of magnetic recording media such as hard disks. Is.

Further, since the force required for separating the magnetic recording medium from the master information carrier is small and the stroke of the motion for separating the magnetic recording medium is also short, the time required for continuous transfer is reduced and the production cost of the magnetic recording medium is reduced. Can be further reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a master information carrier.

FIG. 2 is an enlarged view of a region A in FIG. 1, showing an example of forming a preformatted signal.

FIG. 3 is a cross-sectional view taken along the line BB of FIG. 2, showing a general outline of the master information carrier according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing an outline of a master information carrier and a magnetic recording medium for performing preformat recording according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view showing how preformat recording is performed using the master information carrier according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view showing an outline of a master information carrier for comparison experiment, in which a comparison experiment with the master information carrier according to the first embodiment of the present invention is performed.

FIG. 7 is a sectional view showing an outline of a master information carrier for comparative experiments and a magnetic recording medium for performing preformat recording in the first embodiment of the present invention.

FIG. 8 is a cross-sectional view showing how preformat recording is performed on a master information carrier for comparative experiments according to the first embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a state of adsorption between a master information carrier for comparative experiment and a magnetic recording medium according to the first embodiment of the invention.

FIG. 10 is a sectional view showing the outline of a master information carrier and a magnetic recording medium for performing preformat recording according to the second embodiment of the present invention.

FIG. 11 is a cross-sectional view showing an outline of a master information carrier for comparative experiments and a magnetic recording medium for performing preformat recording in the second embodiment of the present invention.

[Explanation of symbols]

1 master information carrier 2,8 Non-magnetic substrate 2a, 8a surface 3 signal areas 4, 6 Ferromagnetic material 5 recess 5a bottom 100 hard disk (magnetic recording medium) 100a surface

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Ryouchi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP 10-40544 (JP, A) JP 10- 269566 (JP, A) JP 2000-195046 (JP, A) JP 10-320768 (JP, A) JP 11-273070 (JP, A) (58) Fields investigated (Int.Cl. ⁷⁾ , DB name) G11B 5/62-5/86

Claims (2)

(57) [Claims] 1. A magnetic recording medium comprising a master information carrier comprising a non-magnetic substrate and a plurality of ferromagnetic materials deposited on the non-magnetic substrate so as to form a shape pattern corresponding to a signal array. A method of manufacturing a magnetic recording medium, comprising: recording an information signal on the magnetic recording medium by bringing the ferromagnetic materials into close contact with each other and magnetizing the ferromagnetic materials; The non-magnetic substrate of the information carrier has a first surface on which the ferromagnetic material is not deposited, the ferromagnetic material has a second surface facing the magnetic recording medium, and the magnetic recording medium is , A second surface of the ferromagnetic material opposite the third surface of the magnetic recording medium.
From the first surface of the non-magnetic substrate so as to contact the surface.
And the center line average roughness of the second surface is the center of the third surface.
A method of manufacturing a magnetic recording medium, which is greater than the line average roughness and is 0.9 nm or more . 2. A magnetic recording medium comprising a master information carrier comprising a non-magnetic substrate and a plurality of ferromagnetic materials deposited on the non-magnetic substrate so as to form a shape pattern corresponding to a signal array. A method of manufacturing a magnetic recording medium, comprising: recording an information signal on the magnetic recording medium by bringing the ferromagnetic materials into close contact with each other and magnetizing the ferromagnetic materials; The non-magnetic substrate of the information carrier has a first surface on which the ferromagnetic material is not deposited, the ferromagnetic material has a second surface facing the magnetic recording medium, and the magnetic recording medium is , Each of the ferromagnetic materials has a third surface facing the ferromagnetic material, and each of the ferromagnetic materials is arranged so that the first surface of the non-magnetic substrate is in contact with the third surface of the magnetic recording medium. Protruding from the second surface of the material In a state in which the center line average roughness of the first surface is larger than the center line average roughness of the third surface, the center line average roughness of the first surface is larger than the center line average roughness of the third surface. A method of manufacturing a magnetic recording medium, which is 0.9 nm or more.