JP2003022576A - Optical information recording medium and manufacturing method for original disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a partial ROM which can be reproduced by a drive that reproduces a land/groove recording type optical information recording medium having only a recording and reproduction area. SOLUTION: The partial ROM 1 has groove prepits GP formed in groove tracks G of a reproduction-only area 2 and land prepits LP formed in land tracks L of the reproduction-only area 2 so that the reproduced signals of a recording and reproduction area 3 and the reproduction-only area 2 after recording are equal to each other and then can be detected by the same drive, so that the reproduced signals of the reproduction-only area 2 and recording-only area 3 are detected by the drive as nearly the same reproduced signals and then the partial ROM can be reproduced by the drive which reproduces the land/groove recording type optical information recording medium having only a recording and reproduction area without adding any special function to the drive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc having a read-only area in which information data is recorded in advance on both land tracks and groove tracks, and a recording / reproducing area in which information data can be recorded on both land tracks and groove tracks. The present invention relates to an information storage medium and a method for manufacturing a master.

[0002]

2. Description of the Related Art At present, optical discs have become widespread as optical information storage media, but in recent years, the amount of information data to be recorded such as high-pixel image data and audio data is increasing. Therefore, it is desired to increase the capacity of the optical disc, that is, to increase the information recording density.

Several methods have been proposed as a method for realizing this high density, and one of them is a land / groove recording method. This is a method of recording information data on both a groove track, which is a guide groove formed for tracking control for controlling the laser beam to be accurately positioned on the track, and a land track, which is between the guide grooves. . As a result, the information recording density is doubled as compared with the optical disc in which the information data is recorded only on the land track, and the information recording density can be increased. However, since the pits are adjacent to each other, the occurrence of crosstalk noise in tracking control becomes a problem.

A method for solving this is disclosed in Japanese Patent Laid-Open No. 6-338.
No. 064 is proposed. According to this, the groove track depth is λ / 7, where λ is the wavelength of the laser beam.
By setting λ / 5, crosstalk noise due to adjacent pits can be prevented (hereinafter, λ is the wavelength of the laser beam).

Such an optical disk of land / groove recording system is widely used for supplying software such as an operating system and games. There is a limit to the information recording capacity of hard disks such as personal computers in which this optical disk is used.
It is desirable that information data related to software can be recorded on the optical disc on which the software is recorded. Therefore, it is required that the user can additionally write or write the data based on the read-only data recorded in advance on the optical disc. That is, it is necessary to provide a reproduction-only area in which information data is recorded in advance and a recording / reproduction area in which recording / reproduction can be performed, on one optical disk.

When this is realized by an optical disc having only a recording / reproducing area such as a CD-R or a CD-RW, information data is recorded in a part of the recording / reproducing area before shipment of the optical disc, and this information data is recorded. This can be realized by treating the area in which is recorded as a read-only area, but since it is necessary to record information data on each optical disk and mass production is difficult, the cost of the optical disk increases.

As an optical disk that solves this problem, for example, in Japanese Unexamined Patent Publication No. Hei 8-22640, information data is recorded by forming uneven pits in a partial area of the optical disk, and this area is used as a read-only area. It has been proposed to use the remaining area as a recording / reproducing area. As described above, an optical disk in which a read-only area in which information data is recorded in advance and a recording / playback area capable of recording / playback is provided on one optical disk is used as a partial ROM (Read Only Memo).
ry). This partial ROM is injection molded by a stamper having concave and convex pits, so that information data can be recorded in advance.
Since mass production is possible, cost reduction can be realized.

As a method of manufacturing such a partial ROM, for example, a method of manufacturing an optical disk master has been proposed in Japanese Patent Laid-Open No. 10-64123. In this manufacturing method, as shown in FIG. 15B, a first photoresist layer 102 is formed on a glass substrate 101, and the first photoresist layer 102 is not dissolved in a developing solution to form recording light. On the other hand, a master 105 is used in which an intermediate layer 103 having transparency is formed and a second photoresist layer 104 is formed on the intermediate layer 103.

When forming shallow pits / grooves 106a as shown in FIG. 15C, the first recording light for exposing only the second photoresist layer 104 from the second photoresist layer 104 side is applied. The master 105 is irradiated (see FIG. 15A) to form a latent image 107a on the second photoresist layer 104 (see FIG. 15B).

When forming the deep pits / grooves 106b as shown in FIG. 15 (f), the second recording light for exposing both the first photoresist layer 102 and the second photoresist layer 104 is used. Irradiation (see FIG. 15D) forms a latent image 107b on the first photoresist layer 102 and the second photoresist layer 104 (FIG. 15).
(See (e)).

After the latent image, development of the second photoresist layer 104, etching of the intermediate layer 103, and development of the first photoresist layer 102 are sequentially performed to form shallow pits / grooves 106a (FIG. 15 (c)). )) And deep pits / grooves 106b are formed (FIG. 15).
(See (f)).

As a result, the second photoresist layer 10
4 from the upper surface of the first photoresist layer 102 to the shallow pits / grooves 106a (see FIG. 15).
(See (c)), the master 105 having pits / grooves 106b having a deep depth from the upper surface of the second photoresist layer 104 to the lower surface of the first photoresist layer 102 is manufactured (FIG. 15 (f)). reference). That is, by changing the thickness of the photoresist layers 102 and 104 and the intermediate layer 103, the pit / groove 10 having a desired depth can be obtained.
6 can be obtained.

The master 105 manufactured in this manner is electroformed, and the electroformed layer formed on the master 105 is peeled off from the master 105 to form pits having two kinds of depths formed on the master 105. / A stamper which is an electroformed layer having the groove 107 on the surface is produced. Then, using this stamper as a mold, a substrate is manufactured by injection molding, and a recording layer, a reflective layer, a protective layer, and the like are formed on the substrate to complete the partial ROM.

[0014]

Before the partial ROM manufactured as described above became widespread, a land / groove recording type CD-R (Compac) having only a recording / reproducing area was used.
t Disc Recordable) and CD-RW (Compact Disc ReWr)
Itable) drives are widely used. Therefore, the partial ROM is required to have compatibility such that it can be reproduced by a drive for reproducing CD / R or CD-RW of the land / groove recording system.

However, in the partial ROM proposed in Japanese Unexamined Patent Publication No. 8-22640, no track is formed in the read-only area, and a spiral is formed in the track pitch of the read / write area and the read-only area. The pit pitch is different. A boundary area for determining whether the area being reproduced is a reproduction-only area or a recording / reproduction area is provided at the boundary between the reproduction-only area and the recording / reproduction area. Therefore, in order to reproduce this partial ROM, it is necessary to add a special function to the drive or change the condition setting.

Further, in the partial ROMs proposed in Japanese Patent Laid-Open Nos. 8-22640 and 8-77609, two control methods are used for highly accurate tracking control. The drive is required to have a function of realizing the control method and switching the control method.

As described above, in a drive for reproducing an optical disk of a land / groove recording system having only a recording / reproducing area, there is a problem that the partial ROM cannot be reproduced unless a special function is added or condition setting is changed.

Further, if the depths of the groove tracks, groove pits, land pits, etc. are different from each other, it is necessary to stack the photoresist in three layers on the substrate, which causes a problem of increasing the number of steps for manufacturing the partial ROM.

Further, when the groove pits are formed, since the groove track width is conventionally wider than the groove pit width, a wide first recording light (FIG. 16B) for forming a wide groove track 106c as shown in FIG. 16B is formed. 16
(See (a)) and the second for forming the groove pit 106b.
The recording light (see FIG. 15 (d)) and the recording light are combined (see FIG. 16 (c)). The combined light is shown in FIG.
As shown in (c), it has a shape with a widened skirt due to Gaussian distribution. By forming the groove pit / track 106d with this combined light, there is a problem in that the groove pit expands in the radial direction and the circumferential direction of the partial ROM (see FIG. 16D).

The present invention is a partial RO capable of reproducing information data by a drive for reproducing an optical information recording medium of a land / groove recording system having only a recording / reproducing area.
The purpose is to provide M.

It is an object of the present invention to provide a partial ROM capable of easily producing a master.

The present invention provides a method for manufacturing a partial ROM and a master, which can prevent the groove pits from spreading in the radial direction and the circumferential direction when forming the groove pits.

[0023]

The invention according to claim 1 is
A groove track, which is a guide groove for guiding the laser beam, and a land track, which is between the guide grooves, are alternately arranged in the radial direction, and a read-only area and a groove track in which information data is recorded in advance by prepits on both the groove track and the land track. In an optical information storage medium having a recording / reproducing area in which information data can be recorded by pits on both the track and the land track, the reproduction signal of the groove track of the recording / reproducing area and the reproduction-only area after recording can be detected by the same drive. Groove prepits are formed in the groove tracks of the read-only area so that they are equal. Playback is performed so that the playback signals of the land tracks of the recording / playback area and the playback-only area after recording can be detected by the same drive. Land pre-pitting on the land track in the dedicated area There has been formed.

Therefore, the drive detects the reproduction signals of the groove tracks of the reproduction-only area and the recording / reproduction area as substantially the same as the reproduction signals of the land tracks of the reproduction-only area and the recording / reproduction area. It

According to a second aspect of the invention, in the optical information recording medium according to the first aspect, the degree of modulation of the groove track in the recording / reproducing area and the reproduction-only area after the groove prepits are recorded is the same when the reproduction signal is the same drive. The land prepits are formed to be equal to each other so that they can be detected.The land prepits are formed so that the degree of modulation of the land track between the recording / reproducing area and the read-only area after recording is equal to the degree that the reproduction signal can be detected by the same drive. Has been done.

Therefore, the groove tracks of the read-only area and the recording / playback area have substantially the same degree of modulation, and the land tracks of the read-only area and the recording / playback area have substantially the same degree of modulation, and the read-only area and the record / playback area are the same. The drive detects the read signals of the groove track of the area and the read signals of the land track of the read-only area and the read / write area as substantially the same.

According to a third aspect of the present invention, in the optical information recording medium according to the first or second aspect, the groove tracks of the read-only area and the recording / playback area are formed to have substantially the same depth, and the land pre-recording of the read-only area is performed. The pits are formed so that the depth thereof is almost equal to the depth of the groove track, and the groove pre-pits of the read-only area are formed by partially deepening the depth of the groove track of the read-only area. The depths of pits / grooves formed in the reproduction-only area and the recording / reproduction area are two types.

According to a fourth aspect of the present invention, in the optical information recording medium according to the third aspect, the groove prepit depth is set so that the land tracks of the read-only area and the groove tracks of the read-only area have substantially the same degree of modulation. Is set.

Therefore, the land tracks in the reproduction-only area and the groove tracks in the reproduction-only area have substantially the same degree of modulation, and the reproduction signals of the tracks of the reproduction-only area and the recording / reproduction area are detected by the drive as substantially equal reproduction signals. It

According to a fifth aspect of the present invention, in the optical information recording medium according to the fourth aspect, the land prepit depth and the groove track depth of the read-only area are λ / 7 to λ /, where the wavelength of the laser beam is λ. It is set in the range of 5.5, and the groove prepit depth of the reproduction-only area is λ / 4.
It is set at 5 to λ / 4.

Therefore, the prepits in the reproduction-only area and the pits in the recording / reproduction area have the same degree of modulation, crosstalk noise is removed, and the reproduction signal of the track in the reproduction-only area and the reproduction signal of the track in the recording / reproduction area are removed. Are detected by the drive as reproduced signals having substantially equal values.

The invention according to claim 6 is the invention according to claims 1 to 5.
In the optical information recording medium described in any one of 1, the read-only area and the recording / playback area are continuously formed on the same track.

Therefore, there is no area such as a gap for judging the boundary between the reproduction-only area and the recording / reproduction area.

The invention according to claim 7 is the invention according to claims 1 to 6.
In the optical information recording medium described in any one of the above 1, the read-only area and the recording / reproducing area have substantially the same track pitch.

Therefore, it is not necessary to provide an area such as a gap for judging the boundary between the reproduction-only area and the recording / reproducing area in order to change the pitch feed during reproduction.

According to an eighth aspect of the present invention, in the optical information recording medium according to the seventh aspect, the pit width of the read-only area is narrower than the track width of the read-only area.

Therefore, crosstalk noise is reduced.

According to a ninth aspect of the present invention, in the optical information recording medium according to the eighth aspect, the groove track width of the read-only area is narrowed at the groove prepit portion.

Therefore, by narrowing the groove track width of the read-only area only in the groove prepit portion, a narrow and steep groove prepit is formed without changing the entire groove track width of the read-only area.

According to a tenth aspect of the invention, in the optical information recording medium according to the seventh aspect, the groove track width of the read-only area is narrower than the track width of the recording / reproducing area.

Therefore, the groove pre-pits are prevented from spreading in the radial direction orthogonal to the track, and steep pits are formed.

According to an eleventh aspect of the invention, in the optical information recording medium according to the tenth aspect, the groove track width of the read-only area is substantially equal to the groove prepit width of the read-only area.

Therefore, the groove track width is matched with the groove prepit width, and the groove prepits are prevented from spreading in the radial direction orthogonal to the track.
A steep pit is formed.

According to a twelfth aspect of the present invention, in the optical information recording medium according to the eleventh aspect, the groove track width of the read-only area is narrowed at the boundary between the groove track and the groove prepit.

Therefore, the groove pre-pits are prevented from spreading in the circumferential direction along the track, and steep pits are formed.

According to a thirteenth aspect of the present invention, in the optical information recording medium according to the eleventh aspect, a convex portion is formed at an edge of a boundary portion between the groove prepit and the groove track in the read-only area.

Therefore, the edges of the groove prepits are easily detected.

According to a fourteenth aspect of the present invention, the first photoresist layer is formed on the substrate, and the intermediate layer which is transparent to recording light without being dissolved in a developing solution on the first photoresist layer. And a second photoresist layer formed on the intermediate layer, the first recording light and the first photoresist for exposing only the second photoresist layer from the second photoresist layer side. A second recording light that sensitizes both the layer and the second photoresist layer is irradiated to develop a second photoresist layer, an intermediate layer is etched, and a first photoresist is developed after the latent image. In the method of manufacturing a master, the first latent image serving as a groove track on the second photoresist layer by the first recording light and the first photoresist layer by the second recording light. And the A second latent image as a groove prepits formed alternately in the circumferential direction of the master to the photoresist layer.

Therefore, two types of latent images having different depths are alternately formed in the circumferential direction.

According to a fifteenth aspect of the present invention, in the method of manufacturing a master according to the fourteenth aspect, the alternately formed first latent images and second latent images are formed continuously.

Therefore, the latent images are continuously connected to form a groove track.

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disc as an optical information recording medium according to an embodiment of the present invention will be described with reference to FIGS. The optical disc in this embodiment is
It is a partial ROM.

FIG. 1 is a partial ROM of this embodiment.
1 is a schematic plan view of FIG. The partial ROM 1 is a disk-shaped one in which concave groove tracks G which are recording tracks and convex land tracks L are alternately arranged in the radial direction. The partial ROM 1 is provided with a read-only area 2 in which information data is pre-recorded on both the land track L and the groove track G, and a recording / playback area 3 capable of recording information data on both the land track L and the groove track G. Has been. In the present embodiment, the reproduction-only area 2 is formed on the inner peripheral portion of the partial ROM 1, but the present invention is not limited to this.

FIG. 2 is a sectional view taken along line AA showing the layer structure of the partial ROM 1. As shown in FIG. 2, a recording layer 5 for recording information data is formed on a transparent substrate 4 having groove tracks G and land tracks L formed on the surface. A reflective layer 6 that enhances the reflectance is formed on the recording layer 5, and a protective layer 7 that protects from scratches and moisture is formed on the reflective layer 6. Here, a dielectric layer or the like for adjusting or improving the recording characteristics may be formed on the upper surface and the lower surface of the recording layer 5. The transparent substrate 4 is made of glass or resin.

The recording layer 5 is made of a phase change material containing Ag, In, Sn, Te or the like as a main component by sputtering or the like. The phase change material has a property of becoming a crystalline state when gradually cooled after being heated and becoming an amorphous state when rapidly cooled after being melted. Since the phase change material is reversible, the recording layer 5 reversibly changes between a crystalline state and an amorphous state.

Further, in the present embodiment, the recording layer 5
Although the phase change material is used as the material, the material is not limited to this, and for example, a dye or the like that is melted by heat of a high-intensity laser beam may be used.

The reflection layer 6 is made of metal, and as a material thereof, a simple substance such as Au, Al, Ti, or Ni or an alloy thereof can be used. The reflective layer 6 may not be formed. The protective layer 7 is made of an ultraviolet curable resin.

In the partial ROM 1 having such a layer structure, in the recording / reproducing area 3, the intensity of the laser beam applied is changed to reversibly change the crystalline state and the amorphous state of the recording layer 5. , A recording mark which is a pit is formed and information data is recorded (hereinafter, the pit in the recording / reproducing area is a recording mark). Since the light reflectance differs between the crystalline state and the amorphous state, the recorded information data can be read by irradiating a weak laser beam that does not change the crystalline state and detecting the reflected light. In the reproduction-only area 2,
Information data is recorded by forming pits that are pre-pits in the recording track in advance (hereinafter, pre-pits in the reproduction-only area are referred to as pits). Since the light reflectance varies depending on the presence or absence of pits, the recorded information data can be read by irradiating the laser beam and detecting the reflected light.

The partial ROM 1 in which information data is recorded in the reproduction-only area 2 and a part of the recording / reproduction area 3 in this way will be described.

3A and 3B show the vicinity of the boundary between the reproduction-only area 2 and the recording / reproduction area 3 of the partial ROM 1, where FIG. 3A is an enlarged plan view and FIG. 3B is a sectional view taken along line BB of the transparent substrate 4.
Here, the depth reference plane is the surface of the transparent substrate 4, and the layer formed on the transparent substrate 4 is not shown in the BB sectional view. FIG. 4 is a graph showing the relationship between the pit depth and the modulation degree of the land pit LP or the groove pit GP. FIG. 5 is a graph showing the relationship between the pit depth and the push-pull signal.

In the reproduction-only area 2 and the recording / reproduction area 3,
A groove track G having a track width of about ½ pitch is formed. By forming the concave groove track G, a convex land track L having a track width of about ½ pitch is also formed. The depth of the groove track G is λ for removing crosstalk noise.
It is set in the range of / 7 to λ / 5.

In the land track L of the reproduction-only area 2,
The land pits LP are formed so that the reproduction signals of the recording / reproducing area 3 in which the land recording mark LM is formed and the reproduction-only area 2 are equal to the extent that they can be detected by the same drive. The depth of the land pit LP is the groove track G.
In order to make it equal to the depth of, it is necessary to set in the range of λ / 7 to λ / 5.

The land pit L of the reproduction-only area 2
Since the modulation factor of P must correspond to the modulation factor (about 55 to 70%) of the land recording mark LM in the recording / reproducing area 3, as shown in FIG. 4, the depth of the land pit LP is λ /
It is necessary to set in the range of 7.5 to λ / 5.5.

That is, the depth of the land pit LP is λ /
It is set in the range of 7 to λ / 5.5. Here, in the present embodiment, the groove track G and the land pit L are used.
Both Ps are formed with a depth t1 = λ / 6.

In the groove track G of the read-only area 2, the groove pit GP is formed so that the read / write area 3 in which the groove recording mark GM is formed and the read-only area 2 are equal to the extent that they can be detected by the same drive. Are formed. Groove pit G in the reproduction-only area 2
The depth of P is deeper than the depth of the groove track G in the recording / reproducing area 3.

As shown in FIG. 4, since the modulation degree of the groove pit GP in the reproduction-only area 2 needs to correspond to the modulation degree (about 55 to 70%) of the groove recording mark GM in the recording / reproduction area 3, the pit Depth is λ / 4.5 to λ / 3.5
It is necessary to set within the range.

Here, the graph of the land pit LP and the graph of the groove pit GP in FIG. 4 are different, but this is because the modulation degree of the groove pit GP is different from that of the groove pit GP.
This is because the groove pit GP must be deeper than the land pit LP because it is affected by the groove track G between them.

Further, as shown in FIG. 5, if the pit becomes too deep, the push-pull signal, which is a tracking error signal, decreases. The push-pull signal of the groove pit GP is improved by the groove track G of the reproduction-only area 2 as compared with the push-pull signal of only the pit.
Still, it is necessary to set the depth of the groove pit GP to be λ / 4 or less.

That is, the depth of the groove pit GP is λ
It is set in the range of about /4.5 to λ / 4. Here, in the present embodiment, the groove pit GP has a depth of t.
It is formed as 2 = λ / 4.5.

Then, the reproduction-only area 2 and the recording / reproduction area 3
A region such as a gap for judging the boundary is not formed at the boundary part between and. In addition, a reproduction-only area 2 and a recording / reproduction area 3
And have the same track pitch. These are necessary configurations for performing reproduction without distinguishing the reproduction-only area 2 and the recording / reproduction area 3 during reproduction.

In the partial ROM 1 of this embodiment, the depth of the land pit LP is set in the range of λ / 7 to λ / 5.5, and the depth of the groove pit GP is λ / 4.5.
To land recording mark LM
The land pits LP are arranged in the read-only area so that the read signals of the read-write area 3 and the read-only area 2 in which the marks are formed are equal to the extent that they can be detected by the same drive.
The groove pit G is formed so that the reproduction signals of the recording / reproduction area 3 and the reproduction-only area 2 in which the groove recording mark GM is formed are equal to the extent that they can be detected by the same drive.
P is formed on the groove track G of the reproduction-only area 2,
Further, the track pitches of the read-only area 2 and the recording / playback area 3 are made to be the same without forming an area such as a gap for determining a boundary at the boundary portion between the read-only area 2 and the recording / playback area 3 And the recording marks have the same degree of modulation that can be detected by the same drive, crosstalk noise is removed, and the reproduction signal of the pits in the reproduction-only area 2 and the reproduction signal of the recording marks in the recording / reproduction area 3 are substantially equal. Since it is detected by the drive as a reproduction signal, there is no need to distinguish the reproduction-only area 2 from the recording / reproduction area 3 during reproduction, and it is not necessary to add a special function to the drive or change the condition setting. The information data can be reproduced by the drive for reproducing the optical information recording medium of the land / groove recording system having only the above.

In the partial ROM 1 of this embodiment, the groove track G and the land pit LP are formed with a depth of t1 = λ / 6, and the groove pit GP is formed with a depth of t2 = λ / 4.5. Since the pits / grooves formed in the reproduction-only area 2 and the recording / reproduction area 3 have two types, the number of layers formed on the substrate may be two when the master is manufactured. The master can be easily manufactured without increasing the number of manufacturing steps.

[0073]

EXAMPLES Based on the above-described embodiment, more specific first to fourth examples will be described. A comparative example will also be described in the first example. The same parts as those described in the present embodiment are designated by the same reference numerals, and the description thereof will be omitted (the same applies to the following embodiments).

<First Embodiment> The partial ROM 1 of the first embodiment will be described with reference to FIGS. 6, 7 and 8. FIG. 6 shows the recording / reproducing area 3 of the master in this embodiment.
FIG. 6 is an enlarged plan view showing the vicinity of the boundary between the reproduction-only area 2 and 7A and 7B show the relationship between the exposure dose and the resist layer in the present embodiment. FIG. 7A is an exposure dose graph of a groove track beam, FIG. 7B is an exposure dose graph of a groove pit beam, and FIG. 7C is a latent image. 6C is a sectional view of the formed resist layer, and FIG. 6D is a sectional view of the resist layer in which the groove pit GP is formed. In the figure, x, y, and z are symbols indicating the exposure amount (the same applies to the exposure amount graph shown below). FIG. 8 shows the relationship between the exposure dose and the resist layer in this example, (a) is a land pit beam exposure dose graph, (b) is a sectional view of the resist layer on which a latent image is formed, taken along the line D-D. (C) is DD sectional drawing of the resist layer in which the land pit LP was formed.

In the master 8, the first photoresist layer 10 is formed on the disk-shaped substrate 9, and the second photoresist layer 11 is the intermediate layer 12 as in the conventional method of manufacturing the master 8. What was formed through (see FIG. 8B) was used.

Second photoresist layer 11 and intermediate layer 12
Means that the total thickness of the two layers is λ / 6 so that the depth of the groove track G from the surface of the second photoresist layer 11 is λ / 6. The thickness of the first photoresist layer 10 is λ / 4.5-λ / 6 so that the depth of the groove pit GP from the surface of the second photoresist layer 11 is λ / 4.5. (Hereinafter, the reference for the depth is the surface of the second photoresist layer 11).

As the laser beam which is the recording light for irradiating the master 8, a groove track beam for forming the groove track G, a groove pit beam for forming the groove pit GP, and a land pit beam for forming the land pit LP are used. Two laser beams were used.

These laser beams are provided so as to be separated from the master 8 and fixed so as to be irradiated from the second photoresist layer 11 side. Then, a pit / groove is formed by irradiating a laser beam while the master 8 is being rotated by a motor.

Further, the groove track beam and the groove pit beam are arranged on the same circle of the master 8, and the land pit beam is 1 in the outer circumferential direction from the circle on which the groove beam and the groove pit beam are arranged. They are provided on circles separated by a pitch width of / 2. In the present embodiment, the ½ pitch width is 0.75 μm, but it is not limited to this. Since the groove track beam has a larger beam spot diameter than the groove pit beam and the land pit beam, it is possible to form a groove having a width wider than the pit width.

With this structure, the master 8 as shown in FIG. 6 is manufactured. In the manufacturing method of manufacturing the master 8, the master 8 is irradiated with a laser beam having a changed exposure amount, and the photoresist layers 10 and 11 are exposed to light to form a latent image 13.
Are formed, and development, etching, and development are sequentially performed.

First, a groove track beam, which is the first recording light for exposing the second photoresist layer 11 to light, is modulated as shown in FIG.
As shown in (c), a latent image 13a serving as a groove track G was formed on the second photoresist layer 11. Here, the groove track pitch is 1.5 μm.

By changing the exposure amount of the groove track beam between the read-only area 2 and the recording / playback area 3, the groove width of the read-only area 2 is 0.65 μm.
The groove width of the recording / reproducing area 3 was set to 0.75 μm. Here, the exposure amount of the reproduction-only area 2 is smaller than the exposure amount of the recording / reproduction area 3.

Next, a groove pit beam that exposes the first photoresist layer 10 is modulated as shown in FIG. 7B and irradiated on the master 8 to produce the first photoresist as shown in FIG. 7C. A latent image 13b to be the groove pit GP was formed on the photoresist layer 10 of FIG.

The land pit beam, which is the first recording light for exposing the second photoresist layer 11 to light, is shown in FIG.
As shown in FIG.
As shown in (b), the latent image 13 which becomes the land pit LP is formed on the second photoresist layer 11 which becomes the land track L.
c was formed.

Finally, by developing the second photoresist layer 11, etching the intermediate layer 12, and developing the first photoresist layer 10 on the master 8 after the latent image, the photoresist layer 10 is formed. , 11 of the latent image 13 are removed, and as shown in FIGS. 7D and 8C, uneven pits / grooves are formed on the surface by the remaining resist.

As a result, the master 8 has land pits LP and groove tracks G having a depth λ / 6 from the upper surface of the second photoresist layer 11 to the upper surface of the first photoresist layer 10, and the second Depth λ / 4. From the upper surface of the photoresist layer 11 to the lower surface of the first photoresist layer 10.
There will be 5 groove pits GP.

In the reproduction-only area 2 of the master 8 shown in FIG. 6, the groove track has a width of 0.65 μm and a depth of λ /.
6 and the width of the land track is 0.85 μm. The groove pit has a width of 0.60 μm and the depth is λ / 4.5, and the land pit has a width of 0.53 μm.
The depth is λ / 6 at m.

Here, by setting the duty ratio of the groove pit beam signal to 90% of the duty ratio of the land pit beam signal, the width of the groove pit in the reproduction-only area becomes 0.60 μm, and the reproduction-only area becomes 0.60 μm. A reproduction signal of the groove pit GP which is almost the same as the reproduction signal of the land pit LP in the area was obtained.

In the recording / reproducing area 3, the groove track has a width of 0.75 μm and the depth is λ / 6, and the land track has a width of 0.75 μm.

The master 8 thus manufactured is electroformed,
By peeling the electroformed layer formed on the master 8 from the master 8, a stamper, which is an electroformed layer having pits / grooves having two kinds of depths formed on the master 8, is produced. Then, using this stamper as a mold, a substrate is manufactured by injection molding, and the recording layer 5, the reflection layer 6, the protective layer 7, and the like are formed on the substrate, whereby the partial ROM 1 of this embodiment is manufactured.

Partial ROM 1 manufactured in this way
Λ = 650 nm, lens numerical aperture NA = 0.6
A reproduction test was conducted using the No. 5 drive.

Here, the push-pull method is used for the tracking control of the laser beam. What is the push-pull method?
Reflected light or transmitted light from the optical information recording medium is detected by a two-part photodetector having two light receiving areas, and the difference between the photocurrents detected in both light receiving areas is used to detect the difference between the track on the optical disc and the laser beam. This is a method of detecting positional deviation.

In this embodiment, both the groove track G and the land track L in the reproduction-only area 2 are 55 to 6
A modulation degree of about 0% was obtained, and the crosstalk noise was at a level at which there was no problem in reproduction.

Further, in this embodiment, the groove track width of the read-only area 2 is narrower than the track width of the recording / playback area 3, and the pit width of the read-only area 2 is substantially equal to the groove track width of the read-only area 2. This prevents the groove pits GP from spreading in the radial direction and forms steep pits, so that the jitter of the groove pits GP can be improved.

<Comparative Example> As a comparative example, a partial ROM 1 was manufactured with the same structure as that of the first embodiment. The basic partial ROM manufacturing method of the comparative example is the same as that of the first embodiment. The difference from the first embodiment is that the groove track beam and the groove pit beam are overlapped for exposure.

As a result, a groove having a groove track width of 0.75 μm was formed on the entire surface of the master 8 and pits were formed on the groove track G and the land track L in the reproduction-only area 2.

In this case, the groove pit width is 0.7
It became 0 μm, and the duty ratio of the groove pit beam signal was set to 75% of the duty ratio of the land pit beam signal, but the signal was too short and the depth of the shortest groove pit GP became shallower than λ / 4.5. As a result, a good reproduction signal could not be obtained (see FIG. 4).

<Second Embodiment> A partial ROM 1 according to a second embodiment will be described with reference to FIGS. 9 and 10. FIG. 9 shows the recording / reproducing area 3 of the master 8 in this embodiment.
FIG. 6 is an enlarged plan view showing the vicinity of the boundary between the reproduction-only area 2 and FIG. 10 shows the relationship between the exposure dose and the resist layer in the present embodiment. (A) is an exposure dose graph of a groove track beam, (b) is an exposure dose graph of a groove pit beam, and (c) is a latent image. EE sectional view of the formed resist layer, (d) is an EE sectional view of the resist layer in which the groove pit GP is formed.

A master 8 as shown in FIG. 9 is manufactured with the same structure as that of the first embodiment. The basic method of manufacturing the partial ROM 1 of this embodiment is the same as that of the first embodiment. The difference from the first embodiment is that in the manufacturing method of the master 8, the groove track beam is modulated as shown in FIG. 10A and the groove pit beam is modulated as shown in FIG. Sometimes the groove track beam is not illuminated.

First, a groove track beam, which is the first recording light for exposing the second photoresist layer 11 to light, is modulated as shown in FIG.
As shown in FIG. 0 (c), the first latent image 14a serving as the groove track G was formed on the second photoresist layer 11.

Next, a groove pit beam, which is the second recording light for exposing the first photoresist layer 10 and the second photoresist layer 11 to light, is modulated as shown in FIG. Then, as shown in FIG.
A second latent image 15a to be the groove pit GP was formed on the first photoresist layer 10 and the second photoresist layer 11. Here, the latent image 13c that becomes the land pit LP
Are formed exactly as in the first embodiment (see FIG. 8).

Finally, by developing the second photoresist layer 11, etching the intermediate layer 12, and developing the first photoresist layer 10 on the master 8 after the latent image, the photoresist layer 10 is formed. , 11 latent images 14a, 15
The portion a is removed, and as shown in FIG. 10D, uneven pits / grooves are formed on the surface by the remaining resist, and the manufacture of the master 8 shown in FIG. 9 is completed. The method of manufacturing the partial ROM 1 and the reproducing test method performed thereafter are exactly the same as in the first embodiment.

The difference of the present embodiment from the first embodiment of the master is that, as shown in FIG. 9, the groove track width of the reproduction-only area 2 is 0.75 μm and the groove pit G
That is, the width of P is 0.65 μm. That is, the groove track width of the reproduction-only area 2 is narrowed in the groove pit GP portion.

In this embodiment, the first latent image 14a forming the groove track G on the second photoresist layer 11 by the first recording light and the first photoresist layer 10 and the first latent image 14a by the second recording light. Since the second latent images 15a to be the groove pits GP are alternately formed continuously in the circumferential direction of the master on the second photoresist layer 11, two types of latent images having different depths are formed on the circumference of the master. Since the grooves are alternately formed in the same direction, it is possible to form sharp groove pits GP. Since the latent images are continuously connected and the groove track G is formed, tracking control with reduced crosstalk noise can be performed.

Further, by narrowing the groove track width of the reproduction-only area 2 only in the groove pit GP portion, a narrow and steep groove pit GP is formed without changing the entire groove track width of the reproduction-only area 2.
It is possible to improve the jitter of the groove pit GP.

Further, in the present embodiment, although the crosstalk noise is slightly worse than that of the first embodiment, it is at a level at which there is no problem in reproduction, and a modulation degree almost equal to that of the first embodiment can be obtained. It was

<Third Embodiment> A partial ROM 1 of the third embodiment will be described with reference to FIGS. 11 and 12. FIG. 11 is an enlarged plan view showing the vicinity of the boundary between the recording / reproduction area 3 and the reproduction-only area 2 of the master 8 in this embodiment. 12A and 12B show the relationship between the exposure amount and the resist layer in this example. FIG. 12A shows an exposure amount graph of a groove track beam, FIG. 12B shows an exposure amount graph of a groove pit beam, and FIG. The FF sectional view of the formed resist layer, (d) is the FF sectional view of the resist layer in which the groove pit GP was formed.

In the same configuration as that of the first embodiment, FIG.
The master 8 as shown in FIG. The basic method of manufacturing the partial ROM 1 of this embodiment is the same as that of the second embodiment. The difference from the second embodiment is that, in the method of manufacturing the master 8, the groove track beam is modulated as shown in FIG. 12A, and the exposure amount of the read-only area 2 is larger than that of the recording / reproducing area 3. That's a few.

First, a groove track beam, which is the first recording light, is modulated as shown in FIG. 12A and applied to the master 8, and as shown in FIG. 12C, a second photoresist layer is formed. 11 shows the first latent image 14 which becomes the groove track G.
b was formed.

Next, the groove pit beam which is the second recording light is modulated as shown in FIG. 12B and applied to the master 8 to produce the first photoresist as shown in FIG. 12C. A second latent image 15b to be the groove pit GP was formed on the layer 10 and the second photoresist layer 11. Further, the latent image 13c to be the land pit LP is formed exactly as in the first embodiment (see FIG. 8).

Lastly, the master 8 after the latent image is developed with the second photoresist layer 11, the intermediate layer 12 is etched, and the first photoresist layer 10 is developed to develop the photoresist layer 10. , 11 latent images 14b, 15
The portion b is removed, and as shown in FIG. 12D, uneven pits / grooves are formed by the remaining resist on the surface, and the manufacture of the master 8 shown in FIG. 11 is completed. The method of manufacturing the partial ROM 1 and the reproducing test method performed thereafter are exactly the same as in the first embodiment.

The difference from the second embodiment of the master disk in this embodiment is that, as shown in FIG. 11, the groove track width of the read-only area 2 and the width of the groove pit GP are equal to 0.65 μm. That is. The groove track width is narrowed at the boundary between the groove track G and the groove pit GP in the reproduction-only area 2.

In the partial ROM 1 of the present embodiment, the groove track width of the reproduction-only area 2 becomes narrower at the boundary between the groove track G and the groove pit GP, so that the groove pit GP expands in the circumferential direction of the master. And the sharp pits are formed, so that the jitter of the groove pits GP can be further improved as compared with the second embodiment.

<Fourth Embodiment> The partial ROM 1 of the fourth embodiment will be described with reference to FIGS. 13 and 14. FIG. 13 is an enlarged plan view showing the vicinity of the boundary between the recording / reproducing area 3 and the reproduction-only area 2 of the master 8 in this embodiment. 14A and 14B show the relationship between the exposure dose and the resist layer in this example. FIG. 14A shows an exposure dose graph of a groove track beam, FIG. 14B shows an exposure dose graph of a groove pit beam, and FIG. 14C shows a latent image. The GG sectional view of the formed resist layer, (d) is the GG sectional view of the resist layer in which the groove pit GP was formed.

In the same configuration as that of the first embodiment, FIG.
The master 8 as shown in FIG. The basic method of manufacturing the partial ROM 1 of this embodiment is the same as that of the third embodiment. The difference from the third embodiment is that in the manufacturing method of the master 8, the exposure amount waveform of the groove pit beam in FIG. 12B changes from the trailing edge of the exposure amount waveform of the groove track beam in FIG. The separation width is set to the separation distance up to the rising edge and the opposite distance, and the separation width is widened to show the waveform of the exposure amount of the groove track beam as shown in FIG. 14A and FIG. 14B. And the waveform of the exposure amount of the groove pit beam is formed.

First, a groove track beam, which is the first recording light, is modulated as shown in FIG. 14A to irradiate the master 8, and as shown in FIG. 14C, the second photoresist layer is formed. 11 shows the first latent image 14 which becomes the groove track G.
c was formed.

Next, a groove pit beam which is the second recording light is modulated as shown in FIG. 14B and irradiated on the master 8 to produce a first photoresist as shown in FIG. 14C. A second latent image 15c to be the groove pit GP was formed on the layer 10 and the second photoresist layer 11. Further, the latent image 13c to be the land pit LP is formed exactly as in the first embodiment (see FIG. 8).

Finally, on the master 8 after the latent image, the second photoresist layer 11 is developed, the intermediate layer 12 is etched, and the first photoresist layer 10 is developed to develop the photoresist layer 10. , 11 latent images 14c, 15
The c portion is removed, and as shown in FIG. 14D, uneven pits / grooves are formed on the surface by the remaining resist, and the manufacture of the master 8 shown in FIG. 13 is completed. The method of manufacturing the partial ROM 1 and the reproducing test method performed thereafter are exactly the same as in the first embodiment.

The difference from the third embodiment of the master disk in this embodiment is that, as shown in FIG.
That is, the convex portion 16 is formed at the edge of the groove pit GP.

In the partial ROM 1 according to the present embodiment, the push-pull signal is lowered and the crosstalk noise is increased at a level at which there is no problem in reproduction as compared with the third embodiment. By forming the convex portion 16 on the edge of the pit GP, the edge of the groove pit GP is easily detected, so that the jitter of the groove pit GP can be further improved.

Although three beams are used in the first to fourth embodiments, the number of beams is not limited to this. For example, when forming a wide groove track G, a beam with a large spot diameter is used.
By dividing the beam of the book into two beams to make them wider, it is not necessary to use a beam with a large spot diameter.
The number of beams can be two.

[0122]

According to the first aspect of the invention, the groove tracks which are the guide grooves for guiding the laser beam and the land tracks which are between the guide grooves are alternately arranged in the radial direction, and both the groove tracks and the land tracks are arranged. In an optical information storage medium having a reproduction-only area in which information data is recorded in advance by pre-pits and a recording-reproduction area in which information data can be recorded by pits on both groove tracks and land tracks, a recording-reproduction area and a reproduction-only area after recording The groove prepits are formed in the groove tracks of the read-only area so that the playback signals of the groove tracks of and become equal to the extent that they can be detected by the same drive. Re-ensure that the playback signal is equal enough to be detected by the same drive. Since the land pre-pits are formed in the land tracks of the dedicated area, the read signals of the groove tracks of the read-only area and the recording / playback area are almost equal to each other. Since the drive detects the reproduction signals as almost the same reproduction signal, there is no need to add special functions to the drive or change the condition settings, and the land / groove recording type optical information recording medium having only the recording / reproducing area is provided. The information data can be reproduced by the drive for reproducing the information.

According to the second aspect of the invention, in the optical information recording medium according to the first aspect, the groove prepits have the same degree of modulation of the groove track in the recording / reproducing area and the reproduction-only area after recording when the reproduction signal is the same. The land pre-pits are formed so that they can be detected by the same drive, and the land prepits are set so that the degree of modulation of the land track between the recording / reproducing area and the read-only area after recording is the same so that the reproduction signal can be detected by the same drive. Since the read-only area and the recording / reproducing area have substantially the same degree of modulation of the groove tracks, the read-only area and the recording / reproducing area have substantially the same degree of land track modulation. The read-only area and the recording / playback area are land tracks as playback signals whose playback signals on the groove track of the recording and playback areas are substantially equal. Since the drive detects the reproduction signals as almost the same reproduction signal, there is no need to add special functions to the drive or change the condition settings, and the land / groove recording type optical information recording medium having only the recording / reproducing area is provided. The information data can be reproduced by the drive for reproducing the information.

According to the third aspect of the present invention, in the optical information recording medium according to the first or second aspect, the groove tracks of the read-only area and the read / write area are formed to have substantially the same depth, and The land prepits are formed so that the depth is almost equal to the depth of the groove track, and the groove prepits in the read-only area are formed by partially deepening the groove track in the read-only area. Since the pits / grooves formed in the reproduction-only area and the recording / reproduction area have two types of depths, the number of layers formed on the substrate may be two when the master is manufactured, which increases the number of manufacturing processes. It is possible to easily manufacture a master without using.

According to the invention described in claim 4, in the optical information recording medium according to claim 3, the groove prepits are arranged so that the land tracks of the read-only area and the groove tracks of the read-only area have substantially the same degree of modulation. Since the depth is set, the land track in the read-only area and the groove track in the read-only area have almost the same degree of modulation, and the read signals in the tracks in the read-only area and the recording / playback area are almost the same. Since it is detected by the drive as a drive, it is not necessary to add special functions to the drive or change the condition settings.
Information data can be reproduced by a drive for reproducing an optical information recording medium of the groove recording system.

According to the fifth aspect of the invention, in the optical information recording medium according to the fourth aspect, the land prepit depth and the groove track depth of the read-only area are λ / 7 to λ where the wavelength of the laser beam is λ. It is set in the range of λ / 5.5, and the groove prepit depth of the read-only area is λ /
Since it is set to 4.5 to λ / 4, the prepits in the read-only area and the pits in the recording / playback area have the same degree of modulation, crosstalk noise is removed, and the playback signal of the track in the playback-only area is removed. Since the drive detects that the reproduction signal of the track in the recording / reproducing area is almost equal to that of the recording / reproducing area, it is not necessary to add a special function to the drive or change the condition setting. The drive for reproducing the optical information recording medium of the groove recording system can accurately perform tracking control to reproduce the information data.

According to the sixth aspect of the invention, in the optical information recording medium according to any one of the first to fifth aspects, the read-only area and the recording / reproducing area are continuously formed on the same track. Therefore, there is no area such as a gap that determines the boundary between the read-only area and the recording / playback area, so there is no need to add special functions to the drive or change the condition settings. Information data can be reproduced by a drive for reproducing the optical information recording medium of the land / groove recording system.

According to the seventh aspect of the invention, in the optical information recording medium according to any one of the first to sixth aspects, since the track pitches of the read-only area and the recording / reproducing area are substantially equal, the pitch at the time of reproduction is set. Since it is not necessary to provide an area such as a gap for judging the boundary between the read-only area and the recording / playback area in order to change the feed, it is not necessary to add special functions to the drive or change the condition settings. Information data can be reproduced by a drive for reproducing an optical information recording medium of a land / groove recording system having only a reproduction area.

According to the eighth aspect of the invention, in the optical information recording medium according to the seventh aspect, since the pit width of the read-only area is narrower than the track width of the read-only area, crosstalk noise is reduced. Highly accurate tracking control is possible.

According to the ninth aspect of the invention, in the optical information recording medium according to the eighth aspect, the groove track width of the read-only area is narrowed at the groove pre-pit portion. By narrowing the width only in the groove prepits, narrow and sharp groove prepits are formed without changing the entire groove track width of the read-only area, so it is possible to easily improve the crosstalk noise of the groove prepits. .

According to the invention of claim 10, claim 7 is provided.
In the described optical information recording medium, since the groove track width of the read-only area is narrower than the track width of the recording / playback area, the groove prepits are prevented from spreading in the radial direction orthogonal to the track, and the steep pit is prevented. Is formed, the crosstalk noise can be further improved.

According to the invention of claim 11, claim 1
In the optical information recording medium described in 0, since the groove track width of the read-only area is almost equal to the groove prepit width of the read-only area, the groove track width is matched with the groove prepit width, and the groove prepits are orthogonal to the track. Since it is prevented from spreading in the radial direction and a sharp pit is formed, crosstalk noise can be improved without lowering the push-pull signal.

According to the invention of claim 12, claim 1
In the optical information recording medium described in 1, the groove track width of the read-only area is narrowed at the boundary between the groove track and the groove prepit, so that the groove prepit can spread in the circumferential direction along the track. Since it is prevented and sharp pits are formed, the jitter of the groove prepits can be further improved.

According to the invention of claim 13, claim 1
In the optical information recording medium described in 1, the convex portion is formed at the edge of the boundary of the groove prepit in the read-only area with the groove track, so that the edge of the groove prepit is easily detected. The pit jitter can be further improved.

According to the fourteenth aspect of the present invention, the first photoresist layer is formed on the substrate, and the first photoresist layer is transparent to recording light without being dissolved in the developing solution. The first recording light and the first recording light for exposing only the second photoresist layer from the second photoresist layer side to the intermediate layer formed and the second photoresist layer formed on the intermediate layer A second recording light that sensitizes both the photoresist layer and the second photoresist layer is irradiated, and after the latent image, development of the second photoresist layer, etching of the intermediate layer, and first photoresist. In the method of manufacturing a master, the master is manufactured by sequentially developing
Recording light of the first latent image forming a groove track on the second photoresist layer and the second recording light forming a second latent image of groove prepits on the first photoresist layer and the second photoresist layer. Since the images and the images are alternately formed in the circumferential direction of the master, two kinds of latent images having different depths are alternately formed in the circumferential direction, so that a steep groove prepit can be formed.

According to the invention of claim 15, claim 1
In the method of manufacturing a master according to item 4, since the alternately formed first latent image and second latent image are continuously formed, the latent images are continuously connected to form a groove track. Therefore, tracking control with reduced crosstalk noise can be performed.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a partial ROM according to an embodiment of the present invention.

FIG. 2 is an AA cross-sectional view showing a layer structure of a partial ROM.

3A and 3B show the vicinity of a boundary between a read-only area and a recording / playback area of a partial ROM, FIG. 3A is an enlarged plan view, and FIG.

FIG. 4 is a graph showing the relationship between the pit depth and the degree of modulation of land pits or groove pits.

FIG. 5 is a graph showing the relationship between pit depth and push-pull signal.

FIG. 6 is an enlarged plan view showing the vicinity of the boundary between the recording / reproducing area and the reproduction-only area of the master according to the first embodiment.

7A and 7B show a relationship between an exposure amount and a resist layer in the first embodiment, FIG. 7A is an exposure amount graph of a groove track beam, FIG. 7B is an exposure amount graph of a groove pit beam, and FIG. FIG. 3D is a sectional view taken along the line CC of the resist layer on which an image is formed, and FIG.

8A and 8B show the relationship between the exposure dose and the resist layer in the first embodiment, FIG. 8A is a land pit beam exposure dose graph, and FIG. 8B is a cross-sectional view of the resist layer on which a latent image is formed. Figure, (c) D of resist layer with land pits
It is a -D sectional view.

FIG. 9 is an enlarged plan view showing the vicinity of the boundary between the recording / reproducing area and the reproduction-only area of the master according to the second embodiment.

FIG. 10 shows the relationship between the exposure dose and the resist layer in the second embodiment, (a) is an exposure dose graph of a groove track beam, (b) is an exposure dose graph of a groove pit beam, and (c) is a latent image. FIG. 6D is a sectional view taken along the line EE of the resist layer having an image formed thereon, and FIG.

FIG. 11 is an enlarged plan view showing the vicinity of the boundary between the recording / reproducing area and the reproduction-only area of the master according to the third embodiment.

FIG. 12 shows the relationship between the exposure dose and the resist layer in the third embodiment, (a) is an exposure dose graph of a groove track beam, (b) is an exposure dose graph of a groove pit beam, and (c) is a latent image. FIG. 4D is a sectional view taken along the line F-F of the resist layer on which an image is formed, and FIG.

FIG. 13 is an enlarged plan view showing the vicinity of the boundary between the recording / reproducing area and the reproduction-only area of the master according to the fourth embodiment.

14A and 14B show the relationship between the exposure dose and the resist layer in the fourth embodiment. FIG. 14A is an exposure dose graph of a groove track beam, FIG. 14B is an exposure dose graph of a groove pit beam, and FIG. FIG. 3D is a GG sectional view of the resist layer on which an image is formed, and (d) is a GG sectional view of the resist layer on which groove pits are formed.

FIG. 15 shows the relationship between the exposure dose and the resist layer in the prior art, (a) is the exposure dose graph of the first recording light,
(B) is a sectional view of a resist layer on which a latent image is formed by the first recording light, (c) is a sectional view of a master on which pits / grooves are formed by the first recording light, and (d) is a second Of exposure light of recording light, (e) is a cross-sectional view of a resist layer on which a latent image is formed by the second recording light, and (f) is a cross-section of a master on which pits / grooves are formed by the second recording light. It is a figure.

16A and 16B show a relationship between an exposure amount and a resist layer in a conventional technique, FIG. 16A is an exposure amount graph of a wide first recording light, and FIG. 16B is a pit / groove formed by the wide first recording light. 3C is a sectional view of the master, FIG. 6C is an exposure amount graph of the combined light, and FIG. 7D is a sectional view of the master in which pits / grooves are formed by the combined light.

[Explanation of symbols]

2 playback-only area 3 recording / playback area 16 convex 9 substrates 10 First photoresist layer 12 Middle class 11 Second photoresist layer 8 master 14 First latent image 15 Second latent image G groove track L Land Truck

Claims (15)

[Claims] 1. A groove track, which is a guide groove for guiding a laser beam, and a land track, which is between the guide grooves, are alternately arranged in the radial direction, and information data is recorded in advance by pre-pits on both the groove track and the land track. In the optical information storage medium having a read-only area and a recording / playback area capable of recording information data by pits on both the groove track and the land track, the groove of the recording / playback area and the read-only area after recording Groove prepits are formed in the groove tracks of the reproduction-only area so that the reproduction signals of the tracks are equal to the extent that they can be detected by the same drive.
Land pre-pits are formed in the land tracks of the read-only area so that the read signals of the land tracks of the recording / playback area and the read-only area after recording are equal to the extent that they can be detected by the same drive. An optical information recording medium characterized by: 2. The groove prepits are formed so that the degree of modulation of the groove tracks in the recording / reproduction area and the reproduction-only area after recording is equal to the extent that a reproduction signal can be detected by the same drive. The land pre-pits are formed so that the degree of modulation of the land tracks in the recording / reproducing area and the reproduction-only area after recording is equal to an extent that a reproduction signal can be detected by the same drive. Item 1. The optical information recording medium according to item 1. 3. The groove tracks of the read-only area and the recording / playback area are formed to have substantially the same depth,
The land prepits in the read-only area are formed so that the depth thereof is substantially equal to the depth of the groove track, and the groove prepits in the read-only area are deep in the groove track of the read-only area. 3. The optical information recording medium according to claim 1, wherein the optical information recording medium is formed so as to be partially deep. 4. The groove prepit depth is set such that the land tracks of the reproduction-only area and the groove tracks of the reproduction-only area have substantially the same degree of modulation. 3. The optical information recording medium described in 3. 5. The land pre-pit depth and the groove track depth of the read-only area have a wavelength of a laser beam of λ.
Is set in the range of λ / 7 to λ / 5.5, and the groove prepit depth of the reproduction-only area is λ / 4.5.
5. The optical information recording medium according to claim 4, wherein the optical information recording medium is set in the range of .lamda. / 4. 6. The optical information recording medium according to claim 1, wherein the reproduction-only area and the recording / reproduction area are continuously formed on the same track. 7. The optical information recording medium according to claim 1, wherein the reproduction-only area and the recording / reproducing area have substantially the same track pitch. 8. The optical information recording medium according to claim 7, wherein the pit width of the read-only area is narrower than the track width of the read-only area. 9. The optical information recording medium according to claim 8, wherein the groove track width of the reproduction-only area is narrowed at the groove prepit portion. 10. The optical information recording medium according to claim 7, wherein the groove track width of the read-only area is narrower than the track width of the recording / reproducing area. 11. The optical information recording medium according to claim 10, wherein the groove track width of the reproduction-only area is substantially equal to the groove prepit width of the reproduction-only area. 12. The optical information recording medium according to claim 11, wherein the groove track width of the reproduction-only area is narrowed at a boundary portion between the groove track and the groove prepit. 13. The optical information recording medium according to claim 11, wherein a convex portion is formed at an edge of a boundary portion between the groove prepit and the groove track in the reproduction-only area. 14. A first photoresist layer is formed on a substrate, and an intermediate layer which is transparent to recording light without being dissolved in a developing solution is formed on the first photoresist layer, First recording light for exposing only the second photoresist layer from the second photoresist layer side to the second photoresist layer formed on the intermediate layer, and the first photoresist layer And a second recording light that sensitizes both the second photoresist layer, and after exposure, develops the second photoresist layer, etches the intermediate layer, and the first photoresist. In a method of manufacturing a master by sequentially performing the development of 1., a first latent image serving as the groove track and the second recording light are formed on the second photoresist layer by the first recording light. Yo And a second latent image to be the groove prepits are alternately formed on the first photoresist layer and the second photoresist layer in the circumferential direction of the master. 15. The method of manufacturing a master according to claim 14, wherein the first latent images and the second latent images that are alternately formed are continuously formed.