JPH10340475A - Recording device, recording method, and manufacturing method for record medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording device and a recording method which can record information in a record medium using a light beam of short wavelength (e.g. ultraviolet wavelength). SOLUTION: A recording device 100 records information in a record medium 110 including a recording film 110b formed on a substrate 110a. The recording film 110b is not covered by a protection film. The recording device 100 is provided with a laser 101 emitting a laser beam having wavelength of <=488 nm, a driving circuit 121 driving rotation of the record medium 110, a slider 108 constituted so that it is floated from the record medium 110 in a state that the record medium 110 is rotated, a semi-sphere lens 107 constituted integrally with the slider 108, and an optical system 105 irradiating the recording film 110a of the record medium 110 with a laser beam emitted from the laser 101 through the semisphere lens 107 and the slider 108 in a state that the slider 107 is floated from the record medium 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus and method for recording information on a recording medium, and a method for manufacturing another recording medium using the recording medium as a master.

[0002]

2. Description of the Related Art In recent years, with the progress of the information society, an optical recording medium having a higher density and a larger capacity has been required. In order to improve the recording density of the optical recording medium, it is necessary to use a shorter wavelength laser or to increase the numerical aperture (NA) of the objective lens. However, short wavelength lasers and high N
Commercialization of the A lens is not easy. Therefore, by providing a hemispherical lens between the objective lens and the recording medium,
It has been proposed to reduce the beam spot diameter (Appl. Phys. Lett., Vol. 68, No. 2, 1996, pp. 141-14).
3).

FIG. 5 shows the structure of a conventional recording / reproducing optical system 500 using a hemispherical lens. Recording / reproducing optical system 50
0 is an objective lens 502 for condensing the light beam 501;
A hemispherical lens 503 having a high refractive index, a slider 504 having the same high refractive index as the hemispherical lens 503, and a suspension 506 supporting the slider 504 are included. Hemispherical lens 50
3 and the slider 504 are bonded to each other.

A recording medium 505 includes a silicon (Si) substrate 505a, a silicon oxide (SiO ₂ ) film 505b,
It is formed by laminating a TbFeCo film 505c and a silicon nitride (SiN) film 505d in this order.

[0005] The silicon oxide film 505b functions as a heat insulating layer. The TbFeCo film 505c functions as a recording film. The silicon nitride film 505d functions as a protective film.

The operation of the recording / reproducing optical system 500 will be described below.

[0007] The recording medium 505 is rotated during recording and reproduction by a rotation drive system (not shown). Recording medium 505
The air pressure associated with the rotation of the slider acts on the gas bearing surface of the slider 504. As a result, as the recording medium 505 rotates, the slider 504 floats from the recording medium 505,
Thereafter, the user glides on the recording medium 505.

Generally, when a beam spot is formed on a recording medium using only an objective lens, the size of the beam spot is proportional to λ / NA. Here, λ indicates the wavelength of the light beam focused by the objective lens,
NA indicates the numerical aperture of the objective lens.

When an optical element composed of a hemispherical lens and a slider having the same refractive index as that of the optical element is arranged between the objective lens and the recording medium, the size of the beam spot formed on the recording medium is reduced. Is proportional to λ / (n ² NA). Here, n indicates the refractive index of the hemispherical lens and the slider, λ indicates the wavelength of the light beam focused by the objective lens, and NA indicates the numerical aperture of the objective lens. It can be seen that the provision of the hemispherical lens and the slider reduces the size of the beam spot to 1 / n ² .

Appl. Phys. Lett., Vol. 68, No. 2, 1996,
According to pp. 141-143, n = 1.83 for the experimental condition of λ = 830 nm. Therefore, the size of the beam spot can be suppressed to about 30% of the conventional size. Such a reduction in the size of the beam spot is realized by the action of both light transmitted through the slider and evanescent light emitted from the slider.

[0011]

However, evanescent light acts only in the vicinity of the light exit surface of the slider. Therefore, in order to obtain the effect of reducing the size of the beam spot, the distance between the recording film of the recording medium and the slider needs to be λ / 5 or less.

When the wavelength λ of the light beam condensed by the objective lens is relatively long, the distance between the protective film and the slider can be sufficiently increased even when the protective film is formed on the recording film.

However, as the wavelength λ becomes shorter, it becomes more difficult to keep a sufficient distance between the protective film and the slider.
As described above, the distance between the recording film and the slider is required to be λ / 5 or less. This means that as the wavelength λ becomes shorter, a slider that stably runs on the recording medium with a smaller flying height is required. As the flying height of the slider approaches substantially zero, the probability of the slider sliding in contact with the recording medium increases. When the slider slides in contact with the recording medium, the protective film is damaged. This has a significant adverse effect on the reproduced signal. Alternatively, the slider may crash due to the slider coming into contact with the recording medium.

Recently, in order to realize higher-density recording, the wavelength of a light beam focused by an objective lens in such a system tends to be shorter and shorter.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has a sufficient flying height of a slider even when a light beam having a short wavelength (for example, an ultraviolet wavelength) is used.
It is an object to provide a recording device and a recording method capable of recording information on a recording medium.

Another object of the present invention is to provide a manufacturing method for manufacturing another recording medium using a recording medium recorded by the above-described recording method as a master.

[0017]

A recording apparatus according to the present invention records information on a recording medium including a substrate and a recording film formed on the substrate and not covered with a protective film. A recording device, a laser that emits a light beam having a wavelength of 488 nm or less, a driving circuit that drives rotation of the recording medium, and a device that floats from the recording medium when the recording medium is rotating. A hemispherical lens integrally formed with the slider, and the hemispherical lens and the slider which emit the light beam emitted from the laser while the slider is floating from the recording medium. And an optical system for irradiating the recording film of the recording medium through the optical disk, thereby achieving the above object.

It is preferable that the slider and the hemispherical lens are bonded without using an adhesive in a region where the light beam passes.

Preferably, the slider and the hemispherical lens are formed of glass, and the slider and the hemispherical lens have a refractive index of 1.8 or more.

The drive circuit may control the number of rotations of the recording medium so that the recording medium rotates at a constant linear velocity.

The recording medium has a first area used for floating the slider from the recording medium at the start of a recording operation and landing the slider on the recording medium at the end of the recording operation; And a second area for recording.

A recording method according to the present invention is a recording method for recording information on a recording medium including a substrate and a recording film formed on the substrate and not covered with a protective film, Rotating the recording medium, floating the slider from the recording medium while the recording medium is rotating, and emitting laser light from the laser while the slider is floating from the recording medium. 4
Irradiating a light beam having a wavelength of 88 nm or less to the recording film of the recording medium via a hemispherical lens integrally formed with the slider and the slider, thereby achieving the above object. Is achieved.

In the method of manufacturing a recording medium according to the present invention, a step of transferring information recorded on the recording film of the recording medium to another recording medium using a recording medium recorded according to the recording method described above as a master. , Whereby
The above object is achieved.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a recording apparatus 100 according to the present invention. The recording device 100 includes an argon laser (Ar laser) 101, a HeNe laser 112, and a HeNe laser 116. The light beam emitted from the Ar laser 101 is used to record information on the recording medium 110. The light beam emitted from the HeNe laser 112 is used for performing focus control. He
The light beam emitted from the Ne laser 116 is used to control the rotation speed of the recording medium 110.

The Ar laser 101 emits an optical laser having a wavelength of 488 nm or less. As used herein, 488
Wavelengths below nm are defined as "short wavelengths". That is, A
The r laser 101 emits a short-wavelength light beam. The wavelength is, for example, 488 nm, 450 nm, 364 n
m, 351 nm, 275 nm. The use of such a short-wavelength light beam is for recording information on the recording medium 110 at high density.

The light beam emitted from the Ar laser 101 passes through a light modulator 102, a recording optical system 103, and a half mirror 104, and passes through an objective lens 105, a hemispheric lens 1
07 and the slider 108 converge on the recording medium 110. The pattern of information to be recorded on the recording medium 110 is controlled by the optical modulator 102. The optical modulator 102 is driven by an optical modulator driver 118.

The light beam emitted from the HeNe laser 112 is reflected by the recording medium 110. The reflected light enters the light receiver 113 via the half mirror 104 and the half mirror 124. The light receiver 113 generates a focus error signal based on the incident light. The focus servo 119 drives the focus drive coil 106 based on the focus error signal.
In this way, the position of the objective lens 105 is controlled so that the light beam emitted from the Ar laser 101 is always focused on the recording medium 110.

The objective lens 105 is configured not to move in the radial direction. Therefore, the relative position in the horizontal direction between the objective lens 105 and the hemispherical lens 107 does not change. As a result, no aberration is generated with respect to the lateral displacement between the objective lens 105 and the hemispherical lens 107.

The light beam emitted from the HeNe laser 116 is reflected by the rotating motor 114. The reflected light is incident on the light receiver 117 via the half mirror 125. The light receiver 117 is based on the incident light,
A signal indicating the position of the recording medium 110 is generated. The feed pitch monitor 122 monitors the position of the recording medium 110,
The number of rotations of the recording medium 110 is controlled according to the position of the recording medium 110 so that the recording medium 110 rotates at a constant linear velocity. The recording medium 110 is rotated by a rotation motor 114. The rotation speed of the recording medium 110 is controlled by a rotation motor driver 121.

The position of the recording medium 110 is determined by the feed motor 11
5 The feed motor 115 is driven by a feed motor driver 120.

The slider 108 flies above the recording medium 110 while the recording medium 110 is rotating.
It is configured to glide over the recording medium 110.
The slider 108 is supported by a suspension 109.

The hemispherical lens 107 is formed integrally with the slider 108. For example, the hemispheric lens 107 and the slider 108 are polished until the contact surface between the hemispheric lens 107 and the slider 108 becomes optical flat, and the hemispheric lens 107 and the slider 108 are bonded together without using an adhesive at the contact surface.
When an adhesive is used, it is necessary to suppress the variation in the thickness of the contact surface to about ± 0.2 μm. Without the use of an adhesive, such contact surface accuracy is not required.

In the present specification, the hemispherical lens 107 is defined as a lens having a shape obtained by cutting a part of a spherical lens by a predetermined plane. The hemispherical lens 107 and the slider 108 are bonded together with the predetermined plane as a contact surface. From the definition of the hemispherical lens 107, the hemispherical lens 1
07 is not limited to a half lens of a spherical lens. Assuming that the radius of the hemispheric lens 107 is r and the refractive indices of the hemispheric lens 107 and the slider 108 are n, the sum of the height of the hemispheric lens 107 and the height of the slider 108 is preferably set to r or r + r / n.

Hemispherical lens 107 and slider 108
Is preferably formed of glass. Also,
The refractive index of the hemispherical lens 107 and the slider 108 is
It is preferably 1.8 or more.

The recording medium 110 includes a substrate 110a and a substrate 1
And a recording film 110b formed on 10a. In a preferred embodiment, substrate 110a is a glass substrate,
The recording film 110b is a photoresist layer. The photoresist layer is made of a photosensitive material. By irradiating the photoresist layer with light, a pattern representing information is recorded on the photoresist layer.

No protective film is formed on the recording film 110b. Accordingly, even when the light beam used to record information on the recording medium 110 has a short wavelength, a pattern representing information can be formed on the recording film 110b of the recording medium 110.

FIG. 2 shows the structure of the recording medium 110 in the preferred embodiment. As described above, the glass substrate 1
A photoresist layer 110b is formed on 10a. Such a structure is, for example, that a photosensitive material diluted with a solvent is coated on a glass substrate 110 by spin coating.
It is formed by coating on a. The surface of the photoresist layer 110b has a rough surface portion 21 used for floating the slider 108 from the recording medium 110 at the start of the recording operation and landing the slider 108 on the recording medium 110 at the end of the recording operation, and for recording information. And a mirror surface portion 22 for performing the operation. The rough surface portion 21 is formed on the outer peripheral portion of the recording medium 110. The rough surface portion 21 is formed so as to have a roughness of about several tens nanometers to several hundred nanometers. The formation of such a rough surface portion 21 is performed using, for example, a sputter etch method.

FIGS. 3A and 3B show a hemispherical lens 1.
07 and the slider 108 are bonded together, and the periphery of the hemispherical lens 107 is
The structure fixed to is shown. Hemisphere lens 107 and slider 1
By making the contact surface with 08 a nearly perfect optical flat, without using an adhesive on the contact surface,
The hemispheric lens 107 and the slider 108 can be bonded together. As described above, the hemispheric lens 107 and the slider 108 are bonded to each other without using an adhesive in a region where the light beam passes.

Hereinafter, the recording apparatus 10 having the above-described configuration will be described.
The operation of 0 will be described.

Prior to recording information on the recording medium 110, the rotation of the recording medium 110 is started. Recording medium 1
10 is rotated by a rotation motor 114. As the recording medium 110 rotates, the slider 108 floats from the rough surface 21 of the recording medium 110. After the flying height of the slider 108 becomes steady, the feed motor 115 is driven. Thereby, the position of the slider 108 moves from the rough surface portion 21 to the mirror surface portion 22.

Thereafter, the optical modulator 102 is driven according to the information to be recorded on the recording medium 110. As a result, the recording pattern is recorded on the mirror portion 22 of the recording medium 110. The recording medium 110 is fed at a predetermined pitch by a feed motor 115. As a result, the recording pattern is recorded on the mirror portion 22 of the recording medium 110 at a predetermined pitch.

The position of the recording medium 110 is
5 The rotation speed of the recording medium 110 is controlled according to the position of the recording medium 110. As a result, the recording medium 110 is rotated at a constant linear velocity.

As a result of rotating the recording medium 110 at a constant linear velocity, the flying height of the slider 108 can be constant regardless of the position on the recording medium 110 where information is recorded. This is because the slider 108 is supported by the suspension 109 so that the flying height of the slider 108 is constant when the linear velocity of the recording medium 110 is constant. This makes it possible to always keep the conditions for recording information on the recording medium 110 constant.

When a light beam of a short wavelength (for example, ultraviolet wavelength) is narrowed down to a minute beam spot using the hemispherical lens 107 and information is recorded on the recording film 110b of the recording medium 110 using evanescent light, Slider 108
Is between 15 nm and 60 nm.
It is desirable to be about. The distance is 15 nm to 3
Particularly preferably, it is 0 nm.

As in the prior art, if a desired distance between the slider and the recording film is to be ensured when a protective film is formed on the recording film of the recording medium, the flying height of the slider becomes substantially zero. I have to make it. This is because it is necessary to reduce the flying height of the slider by the thickness of the protective film. As a result, it is impossible to avoid scratches and damage to the recording medium.

On the other hand, in the present invention, a recording medium in which a protective film is not formed on a recording film is used. Therefore, even when a light beam having a short wavelength (for example, an ultraviolet wavelength) is used, a flying height of the slider 108 of about 15 nm to 60 nm can be secured. In this manner, information can be recorded at a high density.

FIGS. 4A to 4H show steps of manufacturing the recording medium 210 using the recording medium 110 as a master. FIG. 4 (i) shows a step of reproducing the information on the recording medium 210 thus manufactured. Steps 401 to 4
08 is preferably performed in a class 1000 clean environment. In particular, step 403 is preferably performed in a class 100 clean environment.

Step 401: A photoresist layer 110b is formed on the glass substrate 110a (FIG. 4A).
Thus, the recording medium 110 is formed. The recording medium 110 is formed, for example, by applying a photoresist diluted with a solvent to the glass substrate 110a using a spin coating method. Photoresist layer 110
“b” functions as a recording film for recording a pattern representing information. The thickness of the photoresist layer 110b is about 40 nm after pre-baking.

Step 402: The rough surface portion 21 is formed on the outer peripheral portion of the recording medium 110 (FIG. 4B). The rough surface portion 21
For example, the recording medium 11 is formed using argon ions Ar ^+.
It is formed by sputter-etching only the outer periphery of 0.

Step 403: The recording device 100 (FIG. 1) is used to irradiate the photoresist layer 110b of the recording medium 110 with a short-wavelength light beam emitted from the Ar laser 101 (FIG. 4C). Thereby, a pattern representing information is recorded on the photoresist layer 110b of the recording medium 110. Step 403 is preferably performed in a clean environment including the attachment / detachment of the recording medium 110 to / from the recording apparatus 100. Under a clean environment, the slider can be operated in a stable flying state. as a result,
The reliability of recording can be significantly improved.

Step 404: By developing the photoresist layer 110b, the portion irradiated with the light beam is removed from the photoresist layer 110b (FIG. 4D).
As a result, a pattern representing information is formed in the photoresist layer 1.
Expressed as 10b irregularities.

Step 405: A replica 220 is formed (FIG. 4E). The replica 220 is formed, for example, by sputter-depositing nickel on the surface of the recording medium 110, performing nickel plating using the nickel as an electrode, and peeling the backed one from the recording medium 110. In step 405, the replica 220 facing the rough surface portion 21 provided on the outer peripheral portion of the recording medium 110
Is cut off.

Step 406: The substrate 230 is formed using the replica 220 as a stamper (FIG. 4F).
The substrate 230 is formed from a resin material. Thereby, the photoresist layer 1 formed in step 403 is formed.
The unevenness of 10b is transferred to the substrate 230.

Step 407: Reflective film 24 on substrate 230
0 is formed (FIG. 4G). The reflection film 240 is obtained, for example, by forming aluminum on the substrate 230.

Step 408: A protective film (overcoat) 250 is formed on the reflective film 240.
(H)). The protection film 240 is formed from a resin material. For forming the protective film 240, for example, a spin coating method can be used. Thus, the recording medium 210 including the substrate 230, the reflection film 240, and the protection film 250 is formed.

Step 409: Apply blue laser to recording medium 210
Irradiation from the substrate 230 side reproduces an uneven signal corresponding to the unevenness of the substrate 230 (FIG. 4 (i)).
The blue laser has a wavelength of, for example, 420 nm.

As described above, the recording medium 210 can be manufactured using the recording medium 110 as a master. The information on the recording medium 210 can be reproduced from the substrate 230 as many times as possible using a blue laser. No such clean environment is required for such regeneration. The recording medium 210 can be handled in the same manner as a conventional recording medium.

Steps 401 to 408 described with reference to FIGS. 4A to 4H correspond to the read-only recording medium 2.
This is a process required when manufacturing No. 10. But,
It is also possible to manufacture a recording medium 210 for recording / reproduction. In order to manufacture the recording medium 210 for recording / reproducing, a track groove is formed in step 403 instead of recording information, and instead of forming an aluminum film in step 407, a magneto-optical film or a phase change recording film or the like is used. May be formed. Thus, in step 409, information can be recorded on the recording medium 210 using the blue laser, and thereafter, the information can be reproduced from the recording medium 210.

In this case, it is preferable that the recording in step 403 is performed at a constant linear velocity, and the reproduction or recording / reproduction in step 409 is performed at a constant angular velocity. Step 40
This is because the recording in step 3 can be stabilized and the access speed in step 409 can be increased.

[0061]

According to the present invention, the stability of a slider can be improved by combining a laser emitting a short-wavelength light beam with a slider and a hemispherical lens that fly over a recording film that is not covered with a protective film. Flying height can be secured. Thereby, a remarkable effect that a recording mark of 0.2 μm or less can be formed stably can be obtained. Further, by bonding the slider and the hemispherical lens on the contact surface without using an adhesive, it is possible to suppress aberrations due to thickness error of the adhesive layer low. As a result, assembly accuracy is significantly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a recording apparatus 100 according to the present invention.

FIG. 2 is a diagram showing a structure of a recording medium 110.

FIGS. 3 (a) and (b) show hemispherical lens 107 after bonding hemispherical lens 107 and slider 108;
FIG. 4 is a diagram showing a structure in which the periphery of the head is fixed to a slider 108 using an adhesive 301.

FIGS. 4A to 4H are diagrams showing steps of manufacturing a recording medium 210 using the recording medium 110 as a master, and FIG.
FIG. 4 is a diagram showing a step of reproducing information on the recording medium 210 manufactured in such a manner.

FIG. 5 is a diagram showing a structure of a conventional recording / reproducing optical system 500.

[Explanation of symbols]

 Reference Signs List 101 Ar laser 102 Optical modulator 103 Recording optical system 104 Half mirror 105 Objective lens 106 Focus driving coil 107 Hemispherical lens 108 Slider 109 Suspension 110 Recording medium 110a Substrate 110b Recording film 112 HeNe laser 113 Light receiver 114 Rotary motor 115 Feed motor 116 HeNe laser 117 Optical receiver 118 Optical modulator driver 119 Focus servo 120 Feed motor driver 121 Rotary motor driver 122 Feed pitch monitor 123 System controller 124, 125 Half mirror

Claims (7)

[Claims] 1. A recording apparatus for recording information on a recording medium including a substrate and a recording film formed on the substrate and not covered with a protective film, wherein the recording device has a wavelength of 488 nm or less. A laser that emits a light beam, a driving circuit that drives rotation of the recording medium, a slider configured to float from the recording medium when the recording medium is rotating, and an integral part of the slider A hemispherical lens configured as follows, and with the slider floating above the recording medium,
An optical system for irradiating the light beam emitted from the laser to the recording film of the recording medium via the hemispheric lens and the slider. 2. The recording apparatus according to claim 1, wherein the slider and the hemispherical lens are bonded together without using an adhesive in a region where the light beam passes. 3. The recording apparatus according to claim 1, wherein the slider and the hemispherical lens are formed of glass, and the slider and the hemispherical lens have a refractive index of 1.8 or more. 4. The recording apparatus according to claim 1, wherein the drive circuit controls the rotation speed of the recording medium so that the recording medium rotates at a constant linear velocity. 5. A recording medium comprising: a first area used to float the slider from the recording medium at the start of a recording operation, and to land the slider on the recording medium at the end of the recording operation; Second for recording information
The recording device according to claim 1, further comprising an area. 6. A recording method for recording information on a recording medium including a substrate and a recording film formed on the substrate and not covered with a protective film, the method comprising: rotating the recording medium. Causing the slider to float from the recording medium while the recording medium is rotating; and
Irradiating the recording film of the recording medium with a light beam having a wavelength of 488 nm or less emitted from a laser through a hemispherical lens integrated with the slider and the slider. 7. A step of transferring information recorded on the recording film of the recording medium to another recording medium using a recording medium having information recorded according to the recording method according to claim 6 as a master. Includes a method for manufacturing a recording medium.