JPS5938946A - Master disk for information storing medium and its production - Google Patents

Abstract

PURPOSE:To produce with high yield a master disk for information storing medium which contains tracking guides and signal information pits formed with high accuracy, by forming the 1st recessing/projecting part on the surface of a substrate and then removing a part of said recessing/projecting parts to obtain the 2nd recessing/ projecting part. CONSTITUTION:A photoresist layer 2 is formed on a substrate 1 made of glass, etc., and the laser light condensed by a lens 3 is exposed to form an exposed part 4 on the substrate. Then the part 4 is removed by developing and fixing, and Cr, etc. is vapor- deposited over the entire surface of the substrate 1. A lift-off process is applied after removing the layer 2 and Cr on the layer 2 to obtain the 1st recessing/projecting part 6. Then a chalcogenite glass layer 7A and then a metallic layer 7B of Cu, Al, etc. are vapor-deposited to form a recessing/projecting forming layer 7. Then the laser light is condensed to form a part 7C where the metal of the layer 7B is doped to the layer 7A. The layer 7 is removed by excluding the part 7C to obtain the 2nd recessing/projecting part 11. The parts 6 and 11 are used as a tracking guide and a signal information pit, respectively. In such a way, a master disk is easily produced for an optical information storing medium having high accuracy.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a master disk for an information storage medium for manufacturing all information storage media capable of writing or reading information using a focused laser source, and the manufacturing thereof. Regarding the method.

[Technical background of the invention and its problems]

Compact discs (CDs) used for digital audio discs (1)'AD) are used as information storage media.
) and yC scientific type video disks, the information is written in a disc or tape shape, and the information can be read using a focused laser beam. output memory
It is disk-shaped or tape-shaped, such as those used in (c o M), and it is possible to write information using a focused laser beam and read information from it. Examples include an information storage medium for recording and reproduction and an erasable information storage medium.

In order to improve the information quality of these information storage media,
The pitch is narrower. For this reason, in order to make the optical disc track follow a predetermined track during reading or writing, a tracking guide consisting of a groove or a convex portion having a step difference with respect to the flat surface is formed in advance on this type of information storage medium. There is. Furthermore, if the track number and sector position indicating the position where information is recorded are all recorded in advance, the software for the recording/reproducing device will be easier. It is also equipped with a signal information flyer tracker consisting of a convex portion (also called a tracking guide with preformatting).

The tracking guide and the signal information bit are formed by the unevenness of the flat surface, and are designed to be read as all information such as differences in the amount of light reflected therefrom. For this reason, the tracking guide is designed to have a depth of, for example, λ/8 (λ is the wavelength of the reading laser beam) so that the track deviation detection signal generated by the diffraction pattern of the light reflected from the guide can be increased and stable tracking can be achieved. 0 or less), and is a rectangular groove with a width of about 0.6 to 0-8 PL. In addition, the signal information bits are determined by the maximum modulation degree (
Is the reading laser light directly above the signal information bit? The depth is set to λ/4 and the width is set to about 1/6 of the spot size of the reading laser beam so that the intensity of the reflected light is the smallest when illuminated.

Such a tracking guide or signal information pin) 1-
In order to mass-produce preparatory information storage media, we create a master record with irregularities to be formed on tracking guides and signal information flyers, and transfer the irregularities of this master onto the substrate surface of the information storage medium through various processes. By the way, the following method is known as a method for making tracking guides and signal information flyers at the manufacturing stage of the above-mentioned master disc. In other words, the first plate is made on a glass substrate whose surface has been completely polished. Regis) Jim t: Form and signal information pin) 1- At the part to be formed, drill a hole until it reaches the substrate by irradiating a sufficient amount of laser light.
In the area where the entire tracking guide is to be formed, the amount of laser light is completely quenched and the entire groove is formed to a depth halfway through the photoresist layer.

In this way, tracking guides with different depths and signal information bits are all formed. However, the sensitivity of the photoresist layer varies depending on the state of the photoresist layer before laser exposure, or it is extremely difficult to control the amount of laser light exposure so that the depth of the tracking guide is uniform everywhere. Therefore, there was a problem that it was not possible to form tracking guides and signal information bits with good quality.Also, as described in Japanese Patent Application Laid-Open No. 48-85025,
There is a method of forming multiple photoresist layers with different sensitivities to create tracking guides and signal information bits, but since photoresist easily dissolves in solvents, it is possible to layer several types of photoresists dissolved in solvent. When applying,
There was a problem in that the underlying photoresist layer was easily attacked, and there was also a problem in that it was technically difficult to apply multiple layers of photoresist uniformly.

Additionally, as a result of this, it has become possible to mass produce all information storage media that can accurately read information using a focused laser beam and perform stable tracking in the case of conventional master discs for information storage media. The problem was that it couldn't be done.

[Purpose of the invention]

The present invention has been developed in view of the above circumstances, and is an information storage medium that can perform positive 1r information reading and stable tracking by being equipped with a precisely formed tracking guide and signal information bits. The overall purpose is to provide all master discs for information storage media that can contribute to the mass production of information storage media, and furthermore, such master discs for information storage media can be produced relatively easily and with high accuracy, which in turn improves productivity. It is an object of the present invention to provide a method for manufacturing a master disc for an information storage medium, which can reduce the manufacturing cost.

[Summary of the invention]

The first invention is a master disk for mass producing an information storage medium in which information can be read by a focused laser beam, and includes a substrate having a first uneven portion on its surface, and a substrate provided on the surface of the substrate. The second layer was formed by completely removing a part of the unevenness forming layer.
It is characterized by comprising a concave and convex portion. The second invention includes a step t-i in which an unevenness forming layer is provided on the surface of the substrate having the first unevenness formed on the collection surface, and a second unevenness is formed by removing a part of the unevenness forming layer. It is created with all the features.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An information storage medium master and a method for manufacturing the same according to the present invention will be described below with reference to the drawings.

FIG. 1 (5-1) is a cross-sectional view showing the manufacturing method according to the first embodiment of the present invention in the order of steps.

First, as shown in FIG. 1(a), a photoresist layer 2 is formed by coating a positive type t-spinner on a glass substrate 1 whose surface has been completely polished. Then, the entire photoresist layer 2 is exposed concentrically or spirally with a laser beam focused by an objective lens 6 to form a photoresist exposed portion 4. After that, this photoresist layer 2'f is developed and fixed, and the photoresist exposed area 4 is
Then, as shown in FIG. 1(b), a tracking guide is formed by vacuum evaporating or sputtering Cr to a thickness of 700A on the substrate 1 and the photoresist W42 remaining on the substrate. Provide M5.

At this time, since the tracking guide forming layer 5 is thinner than the thickness of the photoresist layer 2, the tracking guide forming layer 5 is divided at the side portions of the photoresist layer 2. Then, when the photoresist layer 2 is dissolved in an organic solvent, the tracking guide forming layer 5 on the photoresist scraps 2 is also removed, and the tracking guide forming layer 5 in the portion in contact with the substrate 1 remains, As a result, the first uneven portion 6 is formed (see Fig. 1 (
See C).

Next, 1. Radiation energy is absorbed on the surface of the substrate 1 on which the first uneven portion 6 is formed in this way, and the temperature becomes high partially, and 92 kinds of substances are mixed or diffused. The unevenness forming layer 7 is made of this material. For example, as shown in FIG. 1(d)K, As2
S3. As2Se2, As-5-Te system.

A chalcogenide glass layer 7A' made of As-5-5t or the like is formed, and a metal layer 7Bt of Cu, +At or the like is further formed thereon by vacuum evaporation or sputter evaporation. The surface of the unevenness forming layer 70 formed in this manner has a 1ξ uneven shape that substantially follows the first unevenness portion 6.

Then, as shown in FIG. 1 (-), the substrate 1 is placed on a turntable and rotated, and then the objective lens 9 focuses the laser beam [and the laser beam is positioned above the first uneven portion B]. It irradiates the metal layer 7B that has been exposed and traces it all.

This tracing is performed by obtaining a track deviation detection signal based on the diffraction pattern of the laser beam reflected from the metal n7B.

Then, at a position in the trace where a signal information pit is to be provided, the total amount of laser light is increased to cause the chalcogenide glass layers 7 and 4 to be doped with the metal layer 7B. In the figure, 7C is a chalcogenide glass portion doped with metal by Rayleigh'-light as described above. O and the solvent ((37 for 1'u)
When the metal layer 7Bk is dissolved in a ferric chloride solution, 4/- (10% aqueous sodium hydroxide solution) and then immersed in an alkaline solution, the metal-doped chalcogenide glass portion 7C? l? The remaining chalcogenide glass layer 7A is removed, and as a result, the uneven portion 11 of the flute 2 is partially formed on the first uneven portion 6. As shown in (f), a first uneven portion 6 corresponding to a tracking kite with a height of 700λ and a second uneven portion 11 corresponding to a signal information bit of 140 λ (M) are provided on the surface. A master disk for an information storage medium will be manufactured.

The manufacturing method as described above has the following specific effects.

(=f) Since the depth dimensions of the first uneven portion and the second uneven portion are regulated by the thicknesses of the tracking guide forming layer and the uneven forming layer, the tracking guide and signal information pin)k precision , can be formed with good precision.

(b) Since the formation processes of the first uneven part and the second uneven part are completely separated, even if the first uneven part is poorly formed, it can be discarded. There is no need to reduce the yield D' of forming the second uneven portion.

(c) Since the formation process of the first uneven part and the second uneven part are completely separated, a large number of products with only the first uneven part formed can be stocked in advance, and they can be applied as needed. This makes it possible to adopt a process for quickly manufacturing master discs.

(b) When forming the entire second uneven portion, K optically traces the top of the first uneven portion, so high mechanical precision is especially required for the objective lens feeding mechanism that focuses the laser beam completely. Therefore, it is possible to simplify and downsize the manufacturing equipment.

In addition, in the master disk for information storage medium having the above-described structure, the first uneven portion and the second uneven portion are formed with high accuracy, so that information storage media that are mass-produced using this master disk can be used. A tracking guide with good dimensional accuracy and signal information bits are transferred to the disc, and as a result, a master disc for an information storage medium that can perform accurate reading of information and stable tracking can be obtained.

Next, the second embodiment of the present invention will be explained in Fig. 2 (
α) to (=) are cross-sectional views showing the steps of the second embodiment of the present invention. First, as shown in FIG. 2 (α), six first concave and convex portions are formed in a concentric or spiral shape using, for example, a diamond needle 14 on a glass substrate 1 whose surface has been polished. The depth of the unevenness t is, for example, 7001, which corresponds to λ/8 when the wavelength of the reading laser beam L is λ. On the surface of the substrate 1 formed as shown in FIG. At this time, the surface tit of the unevenness forming layer 7: , the first
The tracking guide 12 is formed so that the uneven portion B has unevenness approximately following the shape of the uneven portion B. Thereafter, the surface of the unevenness forming layer 7 is coated with a photoresist gold spinner to completely form a photoresist layer 8. Then, the substrate 1 is placed on a tongue table and rotated, and the laser 5Y is focused by the objective lens 9 from the outside;
Photoresist layer 8 on the front tracking gas driver 2
irradiate it and trace it. This trace is a track deviation detection signal due to the diffraction pattern of the laser beam reflected from the tracking guide 12. Do it by getting it. Then, the laser source fMk is increased to the extent that an uneven portion 7 of t length 2 is to be provided in this trace, and a photoresist exposed portion 10 is formed in the photoresist layer 8.

Then, as shown in FIG. 2(C), the photoresist layer 8 is developed gradually to remove 10 exposed portions of the photoresist, and the unevenness forming layer 7 is partially finished. , the remaining photoresist layer 8vil--as a mask, the exposed partials of the unevenness forming layer 7 are etched, and the second
As shown in Figure (d), it is desirable to use a ferric nitrate solution with a concentration of 55% as the etching solution to remove the etching partial sound and form the second uneven portion 11 there.

Thereafter, the photoresist layer 8 was removed using an organic solvent to a depth of 700A as shown in FIG. 2(-).
A master disk for an information storage medium is manufactured, which includes a tracking guide 12 of 1400 A and a second concavo-convex portion 11 having a depth of 1400 A and corresponding to a signal information bit.

Even in such a second embodiment, the same effects as in the first embodiment can be obtained. In particular, since the materials of the substrate and the unevenness forming layer are different, the etching depth can be extended to the interface between the two, so that the entire depth of the second unevenness can be made uniform, which is a unique effect.

Next, a sixth embodiment of the present invention will be described.

FIGS. 3(α) to 3(C) are cross-sectional views showing all steps of the manufacturing method according to the sixth embodiment of the present invention.

First, as shown in FIG. 6(α), the entire tracking guide forming layer 5 is provided on a polished glass substrate 1 by vacuum deposition or sputter deposition with a Teflon film thickness of 70 (M).Then, the objective lens 3 focuses the light. The tracking guide forming layer 5 is exposed in a concentric or spiral manner with a laser beam, and this exposed portion is removed at a depth of 70 mm to remove the first layer.
Then, on the surface of the substrate 1 on which the first uneven portion 6 is formed on the surface in this way, a Cttf thickness of 700) is vacuum-deposited or sputter-deposited to form an uneven portion (f47).

At this time, the surface of the unevenness forming layer 7 has the shape 1 of the first unevenness portion 6. exhibits unevenness along the surface. Thus, the tracking guide 12 is formed. Then, as shown in FIG. 6(h), a photoresist layer 8 is formed by spinner coating the surface of the unevenness forming layer 7 with phosphor/cyst. Thereafter, as in the second embodiment, the tracking guide 12 is traced with the laser beam focused by the first objective lens 9, and the total amount of the laser beam is increased at the position where the second uneven portion is to be provided during the tracing. A photoresist exposed portion 10 is formed.

Thereafter, etching and removal of the photoresist layer 8 are performed in the same manner as in the second embodiment, and as shown in FIG. It has a second uneven part 11 corresponding to a bit for use.・IN￥! A master disk for a storage medium will be manufactured.

Even in such a third embodiment, there are differences between the first embodiment and tl.
You can get a similar effect. Next, a fourth embodiment of the present invention will be explained.

FIGS. 4(α) to (-) are cross-sectional views showing the manufacturing method according to the fourth embodiment of the present invention in order of steps.

First, as shown in FIG. 4(a), the surface of the button is polished and coated with a photoresist on the surface of a substrate 1 made of glass at 7° C. using a spinner to form a photoresist layer 2. The entire surface of the photoresist layer 2 is agglomerated concentrically or spirally with the laser beam focused to form a photoresist exposed portion 4. Then, the photoresist layer 2vc is developed and fixed, the photoresist h base portion 4 is removed, and the removed portion is then developed and fixed on the substrate 1.
Expose Xun.

Next, as shown in FIG. 4A, the entire remaining photoresist layer 2 is masked, and the substrate surface 1 exposed from this mask is etched to a depth of 700A.

In this way, the first uneven portion 6 having a depth of 700A is formed. In addition, as an etching liquid,
It is desirable to use a mixed solution of 6% R and 40% ammonium fluoride. Thereafter, the remaining photoresist layer 2 is dissolved and removed using a solvent.

Then, as shown in FIG. 4C, a photoresist layer 8 is entirely formed by spinner coating a negative type photoresist on the substrate 1 on which the first uneven portions 6 are formed. Then, while the substrate 1 is placed on a turntable and rotated, a laser beam focused by an objective lens 9 is irradiated onto the photoresist layer 8 on the first uneven portion 6 and traced.

Then, the amount of laser light is increased at the position where the second uneven portion is to be provided in this trace to form a photoresist exposed portion 10 in the previous photoresist layer 8.

Thereafter, this photoresist layer 8 is developed and fixed, and the portions of the photoresist other than the exposed areas 10 are removed. and the fourth
As shown in Figure (d), an unevenness forming layer 7 is provided on the substrate 1 and the photoresist exposure section 10 by vacuum deposition or sputter deposition with a CrF thickness of 700A. At this time, since the unevenness forming layer 7 is thinner than the thickness of the photoresist exposed portion 10, the thickness of the photoresist m base portion 10 is 11!0.
The unevenness forming layer 7 is divided in parts ~. Therefore, when this photoresist exposed area 10 is dissolved with an organic solvent, the unevenness forming layer 7 on the photoresist exposed area 10 is also removed, as shown in FIG. The unevenness forming layer 7 remains, and the second unevenness portion 11 is formed in the portion where the photoresist exposed portion 10 has been removed (such a method will hereinafter also simply be referred to as a lift-off method). The part of the unevenness forming layer 7 located on the first unevenness part 6 has an uneven shape that is almost the same as that of the first unevenness part 6 1. As a result, a tracking guide 12 is formed. Become. In this way, the tracking guide 12 with a depth of 700A and the tracking guide 12 with a depth of 1400A are formed.
．． A master disk for an information storage medium is manufactured, which is provided with the second uneven portions 11 corresponding to No. 4 signal information pits.

Even in such a fourth embodiment, the same effects as those in the first embodiment can be obtained. In particular, since the second uneven portion is formed by the 1-lift-off method, the cross-sectional shape of the second uneven portion has extremely high precision, and the edge portion can also be formed sharply, which is a unique effect. .

Next, a fifth embodiment of the present invention will be described.

FIGS. 5(a) to 5(g) are cross-sectional views showing the manufacturing method according to the fifth embodiment of the present invention in the order of steps. Detailed explanations of steps similar to those in the fourth embodiment will be omitted.

The different process is a process of forming a substrate having a first unevenness on its surface. That is, as shown in FIG. 5(α)K,
A glass substrate 1 with a polished surface is coated with a negative type photoresist, and then a photoresist layer 2 is formed.
After forming the photoresist layer 2tl, the photoresist layer 2tl is exposed concentrically or spirally to a laser beam focused by an objective lens 6 to form a photoresist exposed portion 4. Thereafter, this photoresist layer 2 is developed and fixed, and the portions of the photoresist other than the exposed portions 4 are removed. Then, as shown in FIG. 5(h) VC, a tracking guide forming layer 5 is deposited on the substrate 1 and the photoresist exposure portion 4 by vacuum deposition or sputter deposition with a CrF thickness of 700.2.
will be established. At this time, since the tracking guide forming layer 5 is thinner than the thickness of the photoresist exposed portion 4, the tracking guide forming layer is divided at the side portions of the photoresist exposed portion 4. Therefore, Figure 5 (
t) As shown in K, when this photoresist exposed portion 4 is dissolved in an organic solvent, the tracking guide forming layer 5 on the photoresist exposed portion 4 is also removed, and the tracking guide forming layer 5 in the portion in contact with the substrate 1 is removed. 7, the first uneven portion 6 is formed in the portion where the photoresist exposed portion 4 has been removed.

In this way, the first uneven portion 6 is provided between the surfaces of the next substrate 1'.
f: After obtaining, the tracking guide 12 and the second concavo-convex portion 11 are formed in the same manner as in the fourth embodiment (fifth
(See figures (d) to (a)).

Does the fifth embodiment have the same effect as the first embodiment? Obtainable. %, since the tracking guide forming layer 5 and the unevenness forming layer 7 are made of the same material, it has the unique effect that the adhesion strength of both layers can be made the same.

Next, a sixth embodiment of the present invention will be described.

FIGS. 6(α) to (d) are cross-sectional views showing all steps in the manufacturing method according to the sixth embodiment of the present invention.0 Detailed explanations of the same steps as in the fourth embodiment are omitted. First, a substrate 1 provided on the surface of the first uneven portion 64 is formed by going through the same process as in the fourth embodiment (see FIG. 6(a)).
)reference).

Next, a process different from that of the fourth embodiment will be explained. In other words, as shown in FIG.
An unevenness forming layer 7'@: is provided by sputter deposition or vacuum deposition to a thickness of 700A. At this time, the surface of the unevenness forming layer 70 is connected to the first unevenness portion 6 tx t! The tracking guide 12 is formed so as to have a similar uneven shape. Furthermore, an etching mask forming layer 1 is formed by vacuum-depositing a thermally sublimable substance such as Tey2 on the upper surface.
5 will be provided. The surface of this etching mask forming layer 15 also has an uneven shape along the first uneven portion 6. Thereafter, while the substrate is placed on a turntable and rotated, the laser beam focused by the objective lens 9 is irradiated onto the etching mask forming layer 15 on the tracking guide 12, and the etching mask forming layer 15 is traced by the reflected light. Then, the intensity of the laser beam is increased at the position where the second unevenness portion is to be provided in this trace, and a part of the etching mask forming layer 15 is completely removed, and a part of the unevenness forming layer 7 is removed from there.
expose. After that, this etching mask forming layer 15
As a mask, the unevenness forming layer 7 is exposed under the KN.
is removed by etching, and a second uneven portion 11 is formed there as shown in FIG. This is desirable. And the etching mask forming layer 15t: 10% sodium hydroxide solution or 10q6
By removing with potassium hydroxide solution, Fig. 6 (
As shown in d), an information storage medium master is manufactured which includes a tracking guide 12 with a depth of 700A and a second uneven portion 11 corresponding to a signal information pit with a depth of 1400A. .

Also in the sixth embodiment, substantially the same effect 4 as in the first embodiment can be obtained.

Next, a seventh embodiment of the present invention will be described.

FIGS. 7(α) to (C) are cross-sectional views showing the manufacturing method according to the seventh embodiment of the present invention in order of steps.

First, by going through the same steps as in the fifth embodiment (detailed explanation thereof will be omitted), the entire substrate having the first uneven portion 6 on its surface is formed (see FIG. 7 (α)). .

Next, as in the sixth embodiment, an unevenness forming layer 7 is provided on the surface of the substrate 1 having the first unevenness portion 6, and an etching mask forming layer 15 is formed on top of the unevenness forming layer 7. By etching the unevenness forming layer 7t and forming the second unevenness portion 11 there (detailed explanation thereof will be omitted) (see FIG. 7 Ch), the depth is 700.
A tracking guide.

12 and depth 1400. A master disc for an information storage medium having second uneven portions 11 corresponding to signal information pits (see FIG. 7(C)) is manufactured.

The seventh embodiment also provides the same effect 4 as the first embodiment.

Next, the eighth embodiment of the present invention will be explained.

FIGS. 8(α) to 8(C) are cross-sectional views illustrating, in order of steps, a construction method that is the eighth embodiment of the present invention. Detailed explanation of steps similar to those in the first embodiment will be omitted.

First, the substrate 1 provided on the surface of the first uneven portion 67 is formed in the same manner as in the first embodiment (see FIG. 8(α)). Next, as shown in FIG. 8(b), the substrate 1 is formed. on the surface of substrate 1 with a thickness of 7
Negative type 7 photoresist ffi spinner coating with 00A to form unevenness forming layer 70 and substrate 1
While the laser beam is placed on a turntable and rotated, the laser beam focused by the objective lens 9 is irradiated onto the unevenness forming layer 7 located on the first unevenness portion 6 and traced. Then, during tracing, the amount of V-day light is increased by setting aside the pits for signal information, and the entire photoresist exposed portion 10 is formed on the unevenness forming layer 7.

When the unevenness forming layer 7 is completely removed except for the photoresist exposed area 10 by developing and fixing it, the remaining photoresist layer 7 is removed as shown in FIG. 8(C).
/A second uneven part 11 is formed by the cyst exposure section 10, and as a result, a first uneven part 6 corresponding to a tracking guide with a height of 700A and a first uneven part 6 with a height of 1400,4 (for M number information/corresponding to a bit) are formed. A master disk for an information storage medium including the second uneven portion 11 will be manufactured.

The eighth embodiment can also provide substantially the same effects as the first embodiment. In particular, the unevenness forming layer vi-
Since it is constructed using a 7-me-7 photoresist, it has all the unique effects of not requiring an etching process and making it possible to form the second uneven portions extremely easily.

Next, a ninth embodiment of the present invention will be described.

FIGS. 9(α) to 9(d) are cross-sectional views showing the manufacturing method according to the ninth embodiment of the present invention in the order of steps. A detailed explanation of the steps similar to those in the eighth embodiment will be omitted.

First, as shown in FIG. 9(a), a photoresist layer 2 is formed by coating a negative type photoresist on a glass substrate 1 whose surface has been completely polished. Further, the surface of the photoresist layer 20 is exposed concentrically or spirally with a laser beam focused by an objective lens to form a photoresist exposed portion 4 . Then, the photoresist layer 2 is developed and fixed, and the portions of the photoresist 4 other than the light portion 4 are removed, and the entire substrate 1 is exposed from the removed portion.

Next, as shown in FIG. 9(h), the remaining photoresist exposure portion 4 is entirely masked, and the surface of the substrate 1 exposed from this mask is etched by a completely closed area 700A.

As a result, a concavo-convex portion 6 having a height of 700 A is formed under the remaining photoresist exposed portion 4. It is preferable to use a mixed solution of 6% hydrofluoric acid and 40% ammonium fluoride as the etching solution.Then, by dissolving and removing the remaining photoresist exposed areas 4 with an organic solvent, the surface will be etched. First uneven portion 6
A substrate 1 having the following structure will be formed.

The subsequent process is the same as in the eighth embodiment, and the unevenness forming layer 7 is entirely formed using a negative type photoresist.
A second uneven portion 11 is formed there (FIG. 9 CC),
(see (d)). As a result, a master disk for an information storage medium is manufactured which includes a first uneven portion 6 corresponding to a tracking guide with a height of 700A and a second uneven portion 11 and 4 corresponding to a signal information bit with a height of 1400λ. Become.

Such a ninth embodiment also has the same characteristics as the first embodiment and #I.
can achieve a similar effect.

It should be noted that the above-mentioned embodiment is just an example), and it is not to be said that various modifications can be made within the scope of the gist of the present invention.

In particular, in each example, one manufacturing method and a master disc for an information storage medium manufactured using the method have been described, but each master disc is manufactured by the method described in the example and is not limited to the following. It is also possible to manufacture it by other methods. In addition, the first
By transferring the concavo-convex portion and the second concave-convex portion, an information storage medium including a tracking guide and a signal information bit is manufactured. Regarding the width of the cross section perpendicular to the direction along , it is also possible to form the first uneven portion and the second uneven portion so that the width of the signal information bit is narrower. In particular, in information storage media manufactured using such master discs, the width of the tracking guide is wider than the width of the signal information bits, so when reading information, the outside of the tracking guide must be used. Even though the amount of light reflected from the tracking guide is much smaller than the amount of light reflected from inside the tracking guide, the amount of photoelectricity reflected from inside the tracking guide is much larger, so that the decrease in light reflection intensity that has conventionally been caused by interference between both reflected lights can be completely suppressed. As a result, the light reflection level on the tracking guide becomes high, and a large difference in light reflection level can be obtained between the light reflection level from the part of the recording layer that stores signal information bits and other information. This improves the S/N ratio for information reading, making it possible to read information accurately.

〔Effect of the invention〕

As is clear from the above explanation, in the information storage medium master of the present invention, the tracking guide and the signal information bits are formed with high precision, so that accurate information reading and stable This has excellent effects such as being able to contribute to the mass production of information storage media that can perform tracking, and furthermore, in the method of manufacturing a master for an information storage medium of the present invention, a tracking guide and a signal information recording medium are used. It is possible to form bits with high precision and relatively easily, and has excellent effects such as improving productivity and reducing manufacturing costs.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(a) are cross-sectional views showing the manufacturing method according to the first embodiment of the present invention in the order of steps, and FIGS. Cross-sectional diagram showing all steps in order,
Fig. 3 (α) to (C) Fi is a cross-sectional view showing the manufacturing method according to the sixth embodiment of the present invention in order of steps, and Fig. 4 (a) to (e) are cross-sectional views showing the manufacturing method according to the fourth embodiment of the present invention. 5 (α) to (7) are cross-sectional views showing the manufacturing method according to the fifth embodiment of the present invention in order of steps, and FIGS. 6 (α) to (d)
) are cross-sectional views shown in order of all steps of the manufacturing method according to the sixth embodiment of the present invention, and FIGS. 8(α) to (C) are sectional views showing the manufacturing method according to the eighth embodiment of the present invention in order of steps, and FIGS. 9(α) to (d) are sectional views showing the ninth embodiment of the present invention. 0 1...Substrate, 6...First uneven portion, 7...
- Unevenness forming layer, 11... second unevenness part. Figure 6

Claims (1)

[Claims] (1) In a master disc for mass production of information storage media capable of reading information using a focused laser beam, a substrate having a first uneven portion on its surface and A master disk for an information storage medium, comprising: a second uneven portion formed by partially removing an unevenness forming layer formed on the surface of a substrate; At least, it is created through a step of providing a first unevenness forming layer on the surface of the substrate, and forming a second unevenness by partially removing this unevenness forming layer. 1. A method for manufacturing a master disc for an information storage medium, which has a slight amount of damage. (3) The unevenness forming layer is a photosensitive layer made of a photosensitive material, and the second unevenness is formed by partially exposing the photosensitive layer to light. 2. The method for manufacturing a master disc for an information storage medium according to item 2. (4) The photosensitive layer is a photoresist layer made of a first resist.
(5) The photosensitive layer absorbs radiant energy and becomes partially heated to a high temperature. 7. The method for manufacturing a master disk for an information storage medium according to claim 6, characterized in that it consists of a set of substances in which 72 different substances are mixed or diffused. (6) The unevenness forming layer is formed of an etching material, and by etching a part of it, a second layer is formed.
3. The method for manufacturing a master for an information storage medium according to claim 2, characterized in that the uneven portions are formed on the uneven portions.