JPH1064123A - Production of optical master disk, optical master disk, stamper for optical disk, and production of stamper for optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing an optical master disk capable of adequately forming patterns of different depths with desired widths, an optical master disk, a stamper for the optical disk and a process for producing the stamper for optical disk. SOLUTION: The optical master disk 1 is formed by washing a glass substrate 2, then subjecting the substrate to an HMDS treatment, forming a first photoresist layer 3 by using a positive type resist material and subjecting the layer to prebaking. After the surface of the first photoresist layer 3 is reverse sputtered, an intermediate layer 4 is formed by using ITO and the substrate of the intermediate layer is subjected to the HMDS treatment and thereafter, a second photoresist layer 5 is formed by using the positive type resist material and is subjected to prebaking. The optical master disk 1 is exposed by recording light La, Lb, by which latent images 3a, 5a, 5a are formed thereon. The optical master disk is then subjected to etching and developing to form half grooves and pits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing an optical disk master, an optical disk master, a method for manufacturing an optical disk stamper, and an optical disk stamper.

[0002]

2. Description of the Related Art Recently, information is reproduced optically,
Optical discs for optically reproducing and recording information have emerged. As such optical discs, for example, CDs
(Compact Disc), CD-ROM
(Compact Disc Read Only Memory) and a magneto-optical disk.

Such an optical disk is generally formed in a disk shape having a diameter of 120 mm or 80 mm and a thickness of 1.2 mm, and is widely used as a recording medium for not only music information but also computer software information. It's being used.

In an optical disk having pits and grooves, the depths are λ / 4n and λ / 8n (λ:
(Reproduction wavelength, n: refractive index of the substrate).
In order to obtain such an optical disk, it is necessary to change the pattern formation of the photoresist on the master optical disk by using pits and grooves.

Heretofore, in order to change the depth of a photoresist pattern, the intensity of a laser to be exposed has been used. That is, a shallow groove is formed by a laser having a low emission intensity, and a deep pit is formed by a laser having a high emission intensity. The depth of the pit is determined by the thickness of the photoresist, but the depth of the groove depends on the intensity of the laser. Fluctuations in the groove depth occur due to fluctuations in laser power and focus signals. In addition, it is very difficult to control the width of the groove.

Therefore, in order to solve the above-mentioned problem, a method for manufacturing an optical disk with a guide groove has been proposed in Japanese Patent Publication No. Hei 6-38299.
Discloses a method for producing guide grooves and pits of an optical disk. The technology described in these publications is the first
A first photoresist layer, an intermediate layer, and a second photoresist layer. The first photoresist layer, the intermediate layer, and the second photoresist layer are laminated in this order to form a groove depth by the thickness of the intermediate layer and the second photoresist layer. By forming the pit depth according to the thickness of the photoresist layer 2, fluctuation in laser power,
Pits and grooves are formed without being affected by fluctuations of the focus signal. In addition, by using a water-soluble or alkali-soluble resin such as polyvinyl alcohol, polyacrylamide, and methylcellulose as an intermediate layer, and forming a two-layer photoresist film above and below the intermediate layer, the intermediate layer has a groove blocking effect, Two types of trapezoidal patterns having different depths are obtained.

[0007]

However, in such a conventional method for manufacturing an optical disk, the thicknesses of the pits and grooves are determined by the thicknesses of the first photoresist layer, the intermediate layer and the second photoresist layer. However, the depth of the pit and the groove can be controlled, but the width of the pit and the groove cannot be controlled.

Further, since the intermediate layer is formed of a water-soluble or alkali-soluble resin such as polyvinyl alcohol or methylcellulose, adhesion to the photoresist film is poor. There was a problem that the layer was peeled off.

Therefore, the first aspect of the present invention is to provide a method for manufacturing a semiconductor device, comprising: performing at least one of reverse sputtering and hexamethyldisilazane on the surface of the intermediate layer before forming the second photoresist layer. It is an object of the present invention to provide a method for manufacturing an optical disk master capable of improving the adhesion between the optical disk and the second photoresist layer and preventing the second photoresist layer from peeling off.

According to a second aspect of the present invention, the adhesion between the first photoresist layer and the intermediate layer is improved by subjecting the surface of the first photoresist layer to reverse sputtering before forming the intermediate layer. It is an object of the present invention to provide a method of manufacturing an optical disc master capable of preventing the intermediate layer from peeling off.

According to the third aspect of the present invention, the baking is performed at 120 ° C. or higher after the exposure and before the development of the second photoresist layer, thereby improving the adhesion of each layer.
It is an object of the present invention to provide a method for manufacturing a master optical disc capable of preventing each layer from being peeled off and forming a latent image by appropriately exposing.

According to a fourth aspect of the present invention, the exposure sensitivity of the first and second photoresist layers is made different and the allowable range of the intensity of the second recording light for exposing only the second photoresist layer is changed. Accordingly, the width of the opening of the first photoresist layer and the width of the bottom portion of the second photoresist layer at the time of pit formation can be controlled to form a pit having no step, and to form a pit having a wide width. It is an object of the present invention to provide a method of manufacturing an optical disc master capable of performing the above-described steps.

According to a fifth aspect of the present invention, the first photoresist layer and the second photoresist layer are formed of a positive type photoresist, and the first photoresist layer and the second photoresist layer are exposed. By using, as the first recording light, a light having a higher exposure intensity than the second recording light exposing only the second photoresist layer, pits are formed by the first recording light, and the second recording light is exposed. Provided is a method for manufacturing an optical disc master capable of easily forming pits and half grooves having different depths by forming a half groove by recording light and forming pits wider than the half groove. It is intended to be.

According to a sixth aspect of the present invention, the intermediate layer is formed so as to have a refractive index and a film thickness through which the recording light transmits 90% or more.
By changing the allowable range of the intensity of the second recording light for exposing only the second photoresist layer, the refractive index and the film thickness of the intermediate layer are controlled to change the intensity of the second recording light. It is an object of the present invention to provide a method of manufacturing an optical disc master in which no step is generated between the first photoresist layer and the second photoresist layer and the width of the half groove can be easily controlled. .

According to a seventh aspect of the present invention, the first photoresist layer is formed of a negative photoresist and the second photoresist layer is formed of a positive photoresist.
By using, as the first recording light for exposing the photoresist layer and the second photoresist layer, a light having a higher exposure intensity than the second recording light for exposing only the second photoresist layer, A half groove is formed by the first recording light, a pit is formed by the second recording light, and pits and half grooves having different depths can be easily formed. It is an object of the present invention to provide a method for manufacturing a master optical disc capable of forming a groove.

The invention according to claim 8 is characterized in that the intermediate layer is formed with a refractive index and a film thickness through which recording light is transmitted by 85% or less.
By changing the recording range of the intensity of the second recording light for exposing only the second photoresist layer, no step occurs between the first photoresist layer and the second photoresist layer, and no pits are formed. It is an object of the present invention to provide a method for manufacturing a master optical disc capable of easily controlling the width of the optical disc.

According to a ninth aspect of the present invention, the first and second photoresist layers are formed of a positive photoresist.
A first exposure pattern having a large depth is exposed by a first recording light for exposing the second photoresist layer, and a first exposure pattern having a small depth is exposed by a second recording light exposing only the second photoresist layer. And a trapezoidal half-groove having a shallower depth and a trapezoidal shape having a greater depth than the half-groove such that the first exposure pattern is exposed wider than the second exposure pattern. It is another object of the present invention to provide an optical disc master capable of forming pits wider than a half groove and capable of obtaining stable tracking and an accurate reproduction signal with respect to the reproduction wavelength of the optical disc.

According to a tenth aspect of the present invention, the first photoresist is a negative photoresist and the second photoresist layer is a positive photoresist, and the first and second photoresist layers are exposed. A first exposure pattern having a small depth is exposed by a first recording light, and a second exposure pattern is exposed by a second recording light which exposes only a second photoresist layer.
, And the first exposure pattern is exposed wider than the second exposure pattern, so that pits and half grooves of required depth and width are easily formed, An object of the present invention is to provide an optical disk master capable of obtaining stable tracking and an accurate reproduction signal with respect to a reproduction wavelength.

According to the eleventh aspect, the stamper surface is cleaned in the order of etching of the first photoresist layer, etching of the intermediate layer, and etching of the second photoresist layer to form pits and half grooves having different depths. It is an object of the present invention to provide a stamper for an optical disc having the following.

According to a twelfth aspect of the present invention, the stamper surface is cleaned in the order of etching of the first photoresist layer, etching of the intermediate layer, and etching of the second photoresist layer to form pits and half grooves having different depths. It is an object of the present invention to provide a method for manufacturing an optical disk stamper that can obtain an optical disk stamper having the following.

[0021]

According to a first aspect of the present invention, there is provided a method for manufacturing an optical disc master, comprising forming a first photoresist layer having a thickness of 300 to 2000 mm on a substrate by a spin coating method. An intermediate layer made of an oxide film having a thickness of 50 ° to 300 ° is formed on the photoresist layer by any one of a sputtering method, a vapor deposition method, and a CVD method, and further, has a thickness of 300 mm by a spin coating method.
{2000} second photoresist layers are sequentially laminated to form the first photoresist layer from the second photoresist layer side.
After exposing with a first recording light that exposes both the photoresist layer and the second photoresist layer and a second recording light that exposes only the second photoresist layer, the second photoresist In the method for manufacturing an optical disk master for manufacturing an optical disk master by sequentially performing development of a resist layer, etching of the intermediate layer, and development of the first photoresist layer, before forming the second photoresist layer, The object is achieved by performing at least one of reverse sputtering and hexamethyldisilazane on the surface of the intermediate layer.

Here, the first photoresist layer and the second photoresist layer are formed to a thickness of 300 ° C. by spin coating.
It is formed to a thickness of 2000 mm.

The intermediate layer is formed on the first photoresist layer by sputtering, vapor deposition, or CVD (Chemical Vap).
our deposition method: vapor deposition) and a thickness of 50 to 30 mm by an oxide film.
It is formed to a thickness of 0 °.

Whether the surface of the intermediate layer is subjected to the reverse sputtering treatment or the hexamethyldisilazane treatment depends on the material of the oxide film forming the intermediate layer. For example, In ₂ O ₃ −
In the case of a 95: 5 wt% SnO ₂ alloy (hereinafter referred to as ITO), hexamethyldisilazane (hereinafter referred to as HMD)
Called S. In the case of SiO ₂ or SiO, both reverse sputtering and HMDS are performed.

According to the above configuration, the adhesion between the intermediate layer and the second photoresist layer can be improved, and the second photoresist layer is peeled off from the intermediate layer when the second photoresist layer is developed. Can be prevented.

According to a second aspect of the present invention, there is provided a method of manufacturing a master optical disc, comprising:
A first photoresist layer having a thickness of {2000} is formed, and a thickness of 5 nm is formed on the first photoresist layer by any one of a sputtering method, a vapor deposition method, and a CVD method.
An intermediate layer made of an oxide film having a thickness of 0 ° to 300 ° is formed, and a second photoresist layer having a thickness of 300 ° to 2000 ° is sequentially formed by a spin coating method. The second photoresist layer is formed from the second photoresist layer side. A first exposing both a first photoresist layer and said second photoresist layer;
After exposing with a recording light of a second type and a second recording light exposing only the second photoresist layer, the development of the second photoresist layer, the etching of the intermediate layer, and the first
In the method of manufacturing an optical disk master for forming an optical disk master by developing the photoresist layer, the above object is achieved by subjecting the surface of the first photoresist layer to reverse sputtering before forming the intermediate layer. doing.

According to the above configuration, the adhesion between the first photoresist layer and the intermediate layer can be improved, and the intermediate layer can be prevented from peeling off during the development of the first photoresist layer. .

In each of the above cases, for example, as described in claim 3, baking is performed at 120 ° C. or more after the exposure and before developing the second photoresist layer. Good.

Here, when the photoresist is baked at a high temperature, the exposure sensitivity decreases. However, since the baking is performed after the exposure, the exposure sensitivity of the photoresist does not decrease.

According to the above configuration, the adhesion of each layer can be improved without lowering the exposure sensitivity of the photoresist, and the layers can be prevented from peeling off during development.

Also, for example, as described in claim 4, the exposure sensitivity of the first photoresist layer and the second photoresist layer are different from each other.
The exposure sensitivity of the photoresist may be changed to change the allowable range of the intensity of the second recording light.

Here, if the exposure sensitivity of the first photoresist layer is lower than the exposure sensitivity of the second photoresist layer, it becomes difficult to form a latent image on the first photoresist layer, In order to form a latent image on the layer, recording light having a high exposure intensity is required. Therefore, by changing the exposure sensitivity of the first photoresist layer and the exposure sensitivity of the second photoresist layer, the width of the pit or half groove can be controlled.

That is, when a positive photoresist is used as the first photoresist layer, a latent image soluble in an aqueous alkaline solution is less likely to be formed on the first photoresist layer, and the second recording light The strength can be increased, and the width of the half groove can be increased. When a positive photoresist is used for the first and second photoresist layers, a step may be generated at the boundary between the photoresist layers. By adjusting the exposure sensitivity of the first and second photoresist layers, the width of the bottom portion of the photoresist layer can be made the same, and the occurrence of steps can be prevented.

Further, when a negative type photoresist is used as the first photoresist layer, a portion which is difficult to form a latent image on the first photoresist layer is increased in a portion which is soluble in an alkaline aqueous solution, and a pit is formed. Can be widened.

According to the above configuration, by adjusting the exposure sensitivity of the first photoresist layer and the second photoresist layer, trapezoidal pits and half grooves having different depths can be easily formed. At the same time, the occurrence of pit steps can be prevented.

Further, for example, as described in claim 5, the first photoresist layer and the second photoresist layer are formed of a positive photoresist whose exposed portions are soluble in an alkaline aqueous solution. The first
May have a higher exposure intensity than the second recording light.

According to the above structure, both the first and second photoresist layers are exposed to the first recording light having a high exposure intensity to form deep pits, and only the second photoresist layer is exposed. Is exposed by the second recording light having a low exposure intensity to form a shallow half groove, and since the exposed portion is soluble in an alkaline aqueous solution, a pit wider than the half groove is easily formed. be able to.

Further, for example, as described in claim 6, the intermediate layer is formed with a refractive index and a thickness through which the recording light is transmitted by 90% or more, and an allowable range of the intensity of the second recording light. May be changed.

Here, when the refractive index of the intermediate layer increases,
The reflection of the recording light at the interface between the second photoresist layer and the intermediate layer increases, the light to the first photoresist layer decreases, and the recording light to the first photoresist layer decreases,
The intensity of the second recording light for exposing only the second photoresist layer can be increased, the latent image of the second photoresist layer can be widened, and the width of the half groove can be widened. That is, the width of the half groove can be controlled by changing the refractive index of the intermediate layer.

When the thickness of the intermediate layer is increased, the amount of recording light absorbed by the intermediate layer increases, and the amount of recording light on the first photoresist layer decreases. The second recording light for exposing only the second photoresist layer can be strengthened by the reduced light, so that the latent image of the second photoresist layer is widened and the width of the half groove is widened. Can be. That is, the width of the half groove can be controlled by changing the thickness of the intermediate layer.

Further, if a positive type photoresist is used for the first and second photoresist layers, a step may occur at the boundary between the photoresist layers, but the refractive index and the thickness of the intermediate layer are changed. Thereby, the first recording beam
Of the photoresist layer can be controlled, and the occurrence of steps can be prevented.

According to the above structure, pits are formed by the first recording light for exposing both the first photoresist layer and the second photoresist layer, and the second pit is formed for exposing only the second photoresist layer. By forming a half groove with the recording light, pits and half grooves having different depths can be easily formed, and pits which are wider than the half groove and have no steps can be formed.

Further, for example, as set forth in claim 7, the first photoresist layer is formed of a negative photoresist whose exposed portion is insoluble in an aqueous alkaline solution, and the second photoresist layer The exposed portion may be formed of a positive photoresist that is soluble in an aqueous alkaline solution, and the first recording light may have a higher exposure intensity than the second recording light.

According to the above arrangement, both the first and second photoresist layers are exposed to the first recording light having a high exposure intensity, and only the second photoresist layer is exposed to the second recording light having a low exposure intensity. Exposure is performed by light. Since the first photoresist layer is a negative type photoresist and the exposed portion is insoluble in an alkaline aqueous solution, a shallow half groove is formed by the first recording light having a high exposure intensity. A pit having a large depth is formed by the second recording light having a low exposure intensity. Therefore, a pit having a width larger than that of the half groove and having no step can be easily formed.

Further, for example, as described in claim 8, the intermediate layer is formed with a refractive index and a film thickness that allow the recording light to pass through 85% or less, and an allowable range of the intensity of the second recording light. By changing the above, the above object is achieved.

Here, the first photoresist layer is formed of a negative photoresist whose exposed portion is insoluble in an alkaline aqueous solution, and the second photoresist layer is formed of a positive photoresist whose exposed portion is soluble in an alkaline aqueous solution. It is formed of a mold photoresist.

When the refractive index of the intermediate layer increases,
The reflection of the recording light at the interface between the second photoresist layer and the intermediate layer increases, the light to the first photoresist layer decreases, and the recording light to the first photoresist layer decreases,
The latent image of the first photoresist layer becomes smaller, the portion soluble in the alkaline aqueous solution becomes wider, and the width of the pit can be increased. That is, the width of the pit can be controlled by changing the refractive index of the intermediate layer.

Further, when the thickness of the intermediate layer is increased, the recording light absorbed by the intermediate layer increases, and the recording light to the first photoresist layer decreases, so that the recording to the first photoresist layer is performed. As the light decreases, the latent image of the first photoresist layer becomes smaller, the portion soluble in the alkaline aqueous solution becomes wider, and the width of the pit can be increased. That is, the pit width can be controlled by changing the thickness of the intermediate layer.

According to the above configuration, the first photoresist layer and the second photoresist layer are adjusted by adjusting the refractive index and the thickness of the intermediate layer.
A half groove is formed by a first recording light exposing both of the photoresist layers, and a pit is formed by a second recording light exposing only the second photoresist layer. Pits and half grooves can be easily formed, and pits narrower than the half grooves can be formed.

An optical disk master according to the ninth aspect of the present invention comprises:
7. An optical disk master manufactured by the optical disk master manufacturing method according to claim 5 or 6, wherein a first exposure pattern having a large depth is exposed by the first recording light, and the second recording light is exposed by the second recording light. The above object is achieved by the second exposure pattern having a small depth being exposed and being formed by exposing the first exposure pattern to be wider than the second exposure pattern. ing.

According to the above configuration, a trapezoidal half-groove having a small depth and pits having a large depth and a width wider than the half-groove can be easily formed, and stable tracking can be performed with respect to the reproduction wavelength of the optical disk. And an accurate reproduction signal can be obtained.

According to a tenth aspect of the present invention, there is provided an optical disk master manufactured by the method for manufacturing an optical disk master according to the seventh or eighth aspect, wherein the first recording light reduces the depth of the first optical disk. Is exposed, a second exposure pattern having a deeper depth is exposed by the second recording light, and the second exposure pattern is exposed to be narrower than the first exposure pattern. The above object is achieved by being formed by the above.

According to the above configuration, a deep pit and a shallow, wide half groove can be easily formed, and stable tracking and accurate reproduction signals can be performed with respect to the reproduction wavelength of the optical disk. Obtainable.

According to the eleventh aspect of the present invention, in the method of manufacturing an optical disk stamper, a Ni film is formed on the optical disk master according to the ninth or tenth aspect by sputtering or vapor deposition, and then Ni is electroformed. Ni from base
After peeling off, the above object is achieved by sequentially performing etching of the first photoresist layer, etching of the intermediate layer, and etching of the second photoresist layer.

According to the above arrangement, in cleaning the stamper for an optical disk, the surface of the stamper may be cleaned in the order of the etching of the first photoresist layer, the etching of the intermediate layer, and the etching of the second photoresist layer. As a result, an optical disk stamper having pits and half grooves having different depths can be obtained.

According to a twelfth aspect of the present invention, there is provided an optical disk stamper according to the ninth or tenth aspect, wherein a Ni film is formed on the optical disk master by sputtering or vapor deposition, and then Ni is electroformed. The above object is attained by manufacturing by sequentially performing etching of the first photoresist layer, etching of the intermediate layer, and etching of the second photoresist layer.

According to the above configuration, in cleaning the stamper for an optical disk, the surface of the stamper may be cleaned in the order of etching the first photoresist layer, etching the intermediate layer, and etching the second photoresist layer. As a result, an optical disk stamper having pits and half grooves having different depths can be obtained.

[0058]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIG. 1 is a diagram showing a method for manufacturing an optical disk to which the first embodiment of the method for manufacturing an optical disk master and the optical disk master according to the present invention is applied, and an optical disk master.

In FIG. 1, after cleaning the glass substrate 2, the surface of the glass substrate 2 was subjected to HMDS.
(Hexamethyldisilazane) treated, the exposed part of which is a positive resist material soluble in an aqueous alkaline solution, TSMR
Using -8900 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), a first photoresist layer 3 is formed to a thickness of 1700 ° by spin coating, and prebaked.

Next, after the surface of the first photoresist layer 3 is reverse sputtered, ITO (In ₂ O ₃ --SnO ₂
5: 5 wt% alloy) by DC magnetron sputtering in an atmosphere of Ar and O ₂ to form an intermediate layer 4 of 50 ° C.
Formed to a thickness of After the surface of the intermediate layer 4 is subjected to HMDS treatment, the second photoresist layer 5 is formed by spin coating using TSMR-8900 as a positive resist material.
Is formed to a thickness of 1700 °, and then pre-baked.

That is, in this embodiment, after forming the first photoresist layer 3 and before forming the intermediate layer 4, the surface of the first photoresist layer 3 is subjected to reverse sputtering,
After the formation of the intermediate layer 4 and before the formation of the second photoresist layer 5, the surface of the intermediate layer 4 is subjected to HMDS treatment, and then the second photoresist layer 5 is formed.

When the first photoresist layer 3, the intermediate layer 4, and the second photoresist layer 5 are formed in this manner, laser exposure, etching, and development are performed to form a half groove (guide groove). ) And form a pit.

Specifically, as shown in FIG. 1, the exposure intensity of the first recording light La for exposing both the first photoresist layer 3 and the second photoresist layer 5 is 5.0 mW,
The second recording light Lb for exposing only the second photoresist layer 5 is set to 2.2 mW, and a laser having a linear velocity of 1.2 m / s is irradiated onto the optical disc master 1 from the first photoresist layer 5 side. To expose. By the first recording light La, as shown in FIG. 1, exposed portions (latent images) 3a, 5a soluble in an alkaline aqueous solution are formed in the first photoresist layer 3 and the second photoresist layer 5, Second recording light L
As a result, a latent image 5b soluble in the alkaline aqueous solution is formed only in the second photoresist layer 5.

After the laser exposure and before the development, the film was baked at 130 ° C. for 10 minutes.
The first development for developing the second photoresist layer 5 is performed. Next, the intermediate layer 4 made of ITO is etched with nitric acid diluted to 10% or less with pure water, and then the first photoresist layer 3 is again formed by DE-3.
Is performed for the second time.

By the above-described development and etching, the portions of the first photoresist layer 3 and the second photoresist layer 5 where the latent images are formed are removed, and only the second photoresist layer 3 has an opening width. 0.68 μm, 1750 depth
台 A trapezoidal half group with a shallow depth is formed,
First photoresist layer 3 and second photoresist layer 5
The opening width is 0.95 μm and the depth is 3
A deep trapezoidal pit having a depth of 450 ° is formed.

Next, a description will be given of a second embodiment of the method for manufacturing the master optical disc and the master optical disc according to the present invention. This embodiment is applied to an optical disk and a method for manufacturing an optical disk similar to the first embodiment. In the description of the present embodiment, the reference numerals used in FIG. Detailed description is omitted.

In the present embodiment, after cleaning the glass substrate 2, the surface of the glass substrate 2 is subjected to HMDS treatment, and the exposed portion is spin-coated using TSMR-8900 which is a positive resist material soluble in an aqueous alkaline solution. 17 by coating method
Forming a first photoresist layer 3 having a thickness of 00 °;
Perform pre-bake.

After the surface of the first photoresist layer 3 is reverse-sputtered, SiO ₂ is subjected to RF in an atmosphere of Ar and O _2.
The intermediate layer 4 which is an oxide film is formed by magnetron sputtering.
Is formed to a thickness of 70 °, and the surface of the intermediate layer 4 is reverse-sputtered.

After the surface of the intermediate layer 4 is subjected to the HMDS treatment, the second photoresist layer 5 is coated with 1700 ° by a spin coating method using TSMR-8900 which is a positive resist.
And a pre-bake is performed.

That is, in this embodiment, before forming the intermediate layer 4, the surface of the first photoresist layer 3 is reversely sputtered, and before the second photoresist layer 5 is formed, 4 is reverse sputtered.

After forming the first photoresist layer 3, the intermediate layer 4 and the second photoresist layer 5 in this manner, laser exposure, etching and development are performed to form half grooves and pits. I do.

Specifically, as shown in FIG. 1, the exposure intensity of the first recording light La is 5.0 mW, and the second recording light L
b was set to 2.4 mW, and a laser having a linear velocity of 1.2 m / s was applied from the first photoresist layer 5 side to the optical disk master 1.
Is exposed to light. As shown in FIG. 1, latent images 3 a and 5 a soluble in an aqueous alkaline solution are formed on the first photoresist layer 3 and the second photoresist layer 5 by the first recording light La, and By the recording light Lb, a latent image 5b soluble in the alkaline aqueous solution is formed only in the second photoresist layer 5.

After the laser exposure and before the development,
After baking at 130 ° C. for 10 minutes, the first development for developing the second photoresist layer 5 is performed with DE-3 which is an alkaline aqueous solution, and hydrofluoric acid diluted to 10% or less with pure water is used. The etching of the intermediate layer 4 formed of SiO ₂ is performed, and then the second development of developing the first photoresist layer 3 by DE-3 is performed again.

By the above development and etching, a shallow trapezoidal half groove having an opening width of 0.72 μm and a depth of 1770 ° is formed, and the opening width is 0.95 μm.
As a result, a deep trapezoidal pit having a depth of 3470 ° is formed.

Next, a description will be given of a third embodiment of the method for manufacturing an optical disk master and the optical disk master according to the present invention. This embodiment is applied to an optical disk and a method for manufacturing an optical disk similar to the first embodiment. In the description of the present embodiment, the reference numerals used in FIG. Detailed description is omitted.

In the present embodiment, after cleaning the glass substrate 2, the surface of the glass substrate 2 is subjected to HMDS treatment, and a thickness of 1700 ° is applied by a spin coating method using TSMR-V90M, a positive resist material having high exposure sensitivity. Then, a first photoresist layer 3 is formed, and pre-baking is performed.

After the surface of the first photoresist layer 3 is reversely sputtered, ITO is removed in a DC atmosphere in an atmosphere of Ar and O _2.
The intermediate layer 4 which is an oxide film is formed by magnetron sputtering.
Is formed to a thickness of 60 °.

After the surface of the intermediate layer 4 is subjected to HMDS treatment, a second photoresist layer 5 is formed by a spin coating method using TSMR-8900, which is a positive resist material, and prebaked.

That is, in this embodiment, before the formation of the intermediate layer 4, the surface of the first photoresist layer 3 is reversely stamped, and the surface of the intermediate layer 4 is subjected to HMDS processing. Further, the first photoresist layer 3 is formed of a photoresist material having higher exposure sensitivity than the second photoresist layer 5.

When the first photoresist layer 3, the intermediate layer 4, and the second photoresist layer 5 are formed as described above, laser exposure, etching, and development are performed to form half grooves and pits.

Specifically, as shown in FIG. 1, the exposure intensity of the first recording light La is set to 5.0 mW and the second recording light L
b was set to 2.4 mW, and a laser having a linear velocity of 1.2 m / s was applied from the first photoresist layer 5 side to the optical disc master 1.
Is exposed to light. As shown in FIG. 1, latent images 3 a and 5 a soluble in an aqueous alkaline solution are formed on the first photoresist layer 3 and the second photoresist layer 5 by the first recording light La, and By the recording light Lb, a latent image 5b soluble in the alkaline aqueous solution is formed only in the second photoresist layer 5.

After the laser exposure and before the development,
After baking at 130 ° C. for 10 minutes, the first development for developing the second photoresist layer 5 is performed with DE-3 which is an alkaline aqueous solution, and ITO is diluted with nitric acid diluted to 10% or less with pure water. Is performed, and then the second development for developing the first photoresist layer 3 by DE-3 is performed again.

By the above-mentioned development and etching, a shallow trapezoidal half groove having an opening width of 0.72 μm and a depth of 1760 ° is formed, and the opening width is 0.95 μm.
As a result, a deep trapezoidal pit having a depth of 3460 ° is formed.

<Experimental Example 1> A first photoresist layer, an intermediate layer, and a second photoresist layer were formed on a glass substrate in this order, and the adhesion of the second photoresist layer on the intermediate layer was examined. The following results were obtained. In the following description of the experimental example, description will be made using the reference numerals in FIG.

In this experiment, first, the second photoresist film 5 was formed without any treatment on the surface of the intermediate layer 4 which was an oxide film. Peeled from layer 4.

However, after the surface of the intermediate layer 4 was reverse-sputtered in Ar gas at 3.8 × 10 ^-3 torr for 1 minute, the second photoresist layer 5 was formed.
The peeling of the second photoresist layer 5 was reduced.

It was also found that the effect of preventing peeling differs depending on the material of the intermediate layer 4. That is, the intermediate layer 4 is
When formed with O, high-temperature baking after HMDS treatment and laser exposure was performed, and peeling of the second photoresist layer 5 was completely prevented. SiO ₂
When the intermediate layer 4 was formed of SiO 2 or SiO, both the reverse sputtering process and the HMDS process were performed, and after the exposure, high-temperature baking was performed. As a result, the peeling of the second photoresist layer 5 was completely prevented. .

Therefore, by performing at least one of reverse sputtering and HMDS processing on the surface of the intermediate layer 4 which is an oxide film, the intermediate layer 4 and the second photoresist layer 5 are formed.
And the second photoresist layer 5 can be prevented from peeling off from the intermediate layer 4 during development.

<Experimental Example 2> A first photoresist layer 3, an intermediate layer 4, and a second photoresist layer 5 are formed on a glass substrate 2 in this order, and an oxide film is formed on the first photoresist layer 3. When the adhesion of the intermediate layer 4 was examined, the following results were obtained.

In this experiment, when forming the second photoresist layer 5 on the intermediate layer 4 which is an oxide film, a reverse sputtering process suitable for the material of the intermediate layer 4 shown in the above-mentioned Experimental Example 1 was performed. At least one of the HMDS processes is performed.

First, the intermediate layer 4 was formed without any treatment on the surface of the first photoresist layer 3. When the first photoresist layer 3 was developed, the first photoresist layer 3 and the intermediate film were formed. The peeling occurred from the boundary of No. 4.

[0093] However, the surface of the first photoresist layer 3 was treated with 3.8 × 10 ^-3 torr in Ar gas to obtain 1 photoresist.
After performing the reverse sputtering for minutes, the intermediate layer 4 was formed, but no peeling occurred.

Therefore, by performing reverse sputtering on the surface of the first photoresist layer 3, the adhesion to the intermediate layer 4 which is an oxide film can be improved. , First photoresist layer 3
The intermediate layer 4 can be prevented from peeling off from the substrate.

<Experimental Example 3> In this experiment, an experiment was conducted in which a latent image was formed by the first recording light La and the second recording light Lb shown in FIG.

That is, the first recording light La causes the first
The latent images 3a and 5a are formed on the photoresist layer 3 and the second photoresist layer 5, respectively.

In this case, since both the first photoresist layer 3 and the second photoresist layer 5 are of a positive type, the latent image portions 3a, 5a are soluble in an aqueous alkaline solution. Therefore, an alkaline aqueous solution is used for developing the second photoresist layer 5, and an acid is used for etching the intermediate layer 4 which is an oxide film.
The use of an alkaline aqueous solution for developing the first photoresist layer 3 enables pit patterning.

The latent image 5b is formed only on the second photoresist layer 5 by the second recording light Lb. Since the second photoresist layer 5 is also of a positive type, the latent image portion 5b is soluble in an alkaline aqueous solution. Second photoresist layer 5
Since an aqueous alkaline solution is used for the development of (1), patterning of a half groove becomes possible. That is, even if the etching of the intermediate layer 4 and the development of the first photoresist layer 3 are performed, a latent image is not formed on the first photoresist layer 3 depending on the second recording light Lb, so that the development is not performed. No pattern is formed on the first photoresist layer 3.

The exposure intensity of the first recording light La is
Since the exposure intensity of the second recording light Lb is higher than that of the second recording light Lb, the width of the pit formed over the first photoresist layer 3 and the second photoresist layer 5 by the first recording light La is the second recording light. Lb is larger than the width of the half groove formed only in the second photoresist layer 5.

Therefore, pits having different depths, half grooves, and pits wider than the half grooves can be easily formed.

<Experimental Example 4> In this experiment, baking was performed after exposure to examine peeling during development. That is,
After the exposure, baking is performed at a temperature higher than the pre-bake temperature of the photoresist.

Specifically, after the above-mentioned exposure, 1 ° C. at 130 ° C.
Baking was performed in an oven for 0 minutes to check whether peeling occurred during development. As a result, no peeling occurred.

Therefore, if baking is performed at a high temperature before exposure, the exposure sensitivity of the first photoresist layer 3 and the second photoresist layer 5 is reduced. However, since the baking is performed at a high temperature after exposure, First photoresist layer 3
And the adhesion between the first photoresist layer 3 and the intermediate layer 5 composed of an oxide film and the adhesion between the intermediate layer 4 and the second photoresist layer 5 without lowering the exposure sensitivity of the second photoresist layer 5. Adhesion can be improved.

<Experimental Example 5> In this experiment, the widths of the pits and the half grooves when the refractive index and the film thickness of the intermediate layer 4 were changed were examined.

That is, the first photoresist layer 3 and the second photoresist layer 5 are formed to a thickness of 1700 ° using TSMR-8900, and the refractive index and the thickness of the intermediate layer 4 are changed. When the widths of the pits and the half grooves were examined, the results shown in FIG. 2 were obtained. In FIG. 2, the maximum opening width of the half groove means a half groove at a limit where a pattern is formed on the first photoresist layer 3 when the exposure intensity (Pw) becomes higher.

In FIG. 2, under the conditions 1 and 2, the intermediate layer 4 was formed of ITO, and the pattern width depending on the ITO film thickness was examined.
Although a half groove having a width of 77 μm was obtained, the pit shape became a step shape as shown in FIG. When the film thickness of ITO was reduced to 50 °, the pit shape became smooth as shown in FIG. 4, but a half groove having a width of 0.68 μm was formed. Under condition 3, when the intermediate layer 4 was formed to a thickness of 70 ° using SiO ₂ having a smaller refractive index than ITO, a half groove wider than that in condition 2 could be formed, and the pit shape also had a stepped shape. It was not formed and was smooth.

The intermediate layer 4 has a thickness of 0 ° to 100 °.
Layer 4 for the exposure wavelength (λ = 458 nm)
When the transmittance of the laser was examined, the result shown in FIG. 5 was obtained.

That is, as shown in FIG. 5, when the intermediate layer 4 is formed to a thickness of 50 ° by ITO, the transmittance is about 9%.
The transmittance was about 88% when the intermediate layer 4 was formed with ITO to a thickness of 60 °. Also, the middle layer 4
Is formed to a thickness of 70 ° with SiO ₂ ,
It was about 95%. From the above results, it was found that when the laser transmittance of the intermediate layer 4 was 90% or more, the pit shape became smooth.

Therefore, when the refractive index of the intermediate layer 4 is increased, the reflection of light at the interface between the second photoresist layer 5 and the intermediate layer 4 is increased, and the light to the first photoresist layer 3 is reduced. However, the amount of light to the first photoresist layer 3 is reduced, so that the second recording light Lb can be increased. As a result, the latent image of the second photoresist layer 5 becomes wider,
As the latent image becomes wider, a wide half groove can be formed. Therefore, by adjusting the refractive index of the intermediate layer 4, the width of the half groove can be controlled.

When the thickness of the intermediate layer 4 is increased, the amount of light absorbed by the intermediate layer 4 increases, and the light to the first photoresist layer 3 decreases, and the light to the first photoresist layer 3 decreases. Is reduced, the second recording light Lb can be strengthened. Accordingly, the latent image of the second photoresist layer 5 is widened, and the width of the half groove can be increased by the amount of the widened latent image. As a result, the width of the half groove can be controlled by adjusting the thickness of the intermediate layer 4.

From the above results, by appropriately adjusting the refractive index and the film thickness of the intermediate layer 4, the width of the half groove can be easily controlled, and the half groove having the target width can be easily adjusted. By controlling the refractive index, the film thickness, and the exposure intensity of the laser, it is possible to easily and appropriately form the film. In addition, stepless pits can be easily formed.

<Experimental Example 6> In this experiment, the formation state of pits and half grooves when the exposure sensitivity of the first photoresist layer 3 and the second photoresist layer 5 was changed was examined.

That is, in this experiment, the intermediate layer 4 was formed to a thickness of 60 ° by ITO, the two photoresist layers 3 and 5 were formed by photoresist materials having different exposure sensitivities, and the widths of the pits and half grooves were changed. Was examined.

Specifically, as shown in FIG. 6, under the condition 1, the first photoresist layer 3 and the second photoresist layer 5 are formed of the same photoresist material (TSMR-8900), and the condition 4 is satisfied. In the first embodiment, the first photoresist layer 3 is made of a high-sensitivity photoresist material, TSMR-V90M.
(Tokyo Ohka Kogyo Co., Ltd.), the second photoresist layer 5
TSM with lower exposure sensitivity than the first photoresist layer 3
It was formed of R-8900.

As a result of the above experiment, as shown in FIG. 6, under the condition 1, the pit has a step as shown in FIG.
Under the condition 4, no step was formed, and similarly to the condition 3 of the experimental example 5, a smooth pit having no step was formed as shown in FIG.

That is, if the exposure sensitivity of the first photoresist layer 3 is lower than that of the second photoresist layer 5, strong light is required to form a latent image on the first photoresist layer 3. Accordingly, it is difficult to form a latent image on the first photoresist layer 3. As a result, the second recording light Lb can be strengthened, and the latent image of the second photoresist layer 5 is widened. As the latent image is widened, the width of the half groove is also widened. As a result, the width of the half groove can be controlled by changing the exposure sensitivity of the first photoresist layer 3 and the second photoresist layer 5.

Further, since a positive type resist is used for the first photoresist layer 3 and the second photoresist layer 5, the boundary between the first photoresist layer 3 and the second photoresist layer 5 is formed. A step as shown in FIG. 3 occurs,
By changing the width of the opening of the first photoresist layer 3 and the width of the bottom of the second photoresist layer 5 by changing the exposure sensitivity of the photoresist, the occurrence of steps can be prevented.

Next, a fourth embodiment of the method of manufacturing an optical disk master and the optical disk master according to the present invention will be described with reference to FIG.
A description will be given based on FIG. In this embodiment, the first photoresist layer is formed of a negative photoresist material.

In this embodiment, the optical disk master 11
Is a negative type resist material FHT-3 whose exposed portion is insoluble in an aqueous alkaline solution after cleaning the glass substrate 12.
Using 32S (manufactured by Fuji Hunt), the first photoresist layer 13 is formed to a thickness of 1700 ° by spin coating.
Is formed and prebaking is performed.

After reverse sputtering of the surface of the first photoresist layer 13, ITO was subjected to DC magnetron sputtering in an atmosphere of Ar and O _2, whereby the intermediate layer 14 was
It is formed to a thickness of 0 °.

After the surface of the intermediate layer 14 is subjected to HMDS processing, a second photoresist layer 15 is formed to a thickness of 1700 ° by spin coating using TSMR-8900, which is a positive resist, and prebaked.

That is, in the present embodiment, the first photoresist layer 13 is formed of a negative photoresist material and the second photoresist layer 15 is formed of a positive photoresist material. Before the formation, the surface of the first photoresist layer 13 is reverse-sputtered, and before the second photoresist layer 15 is formed,
The surface of the intermediate layer 14 formed of O is subjected to HMDS processing.

Thus, the first photoresist layer 1
3. After the formation of the intermediate layer 14 and the second photoresist layer 15, laser exposure, etching and development are performed to form half grooves and pits.

Specifically, as shown in FIG. 7, the exposure intensity of the first recording light La is set to 5.0 mW and the second recording light L
Exposure is performed by irradiating a laser having a linear velocity of 1.2 m / s to the optical disk master 11 from the first photoresist layer 15 side with b being 2.0 mW. First recording light La
As a result, as shown in FIG. 7, the first photoresist layer 1
3, a latent image 13a that is insoluble in an alkaline aqueous solution is formed on the second photoresist layer 15, and a latent image 15a that is soluble in an alkaline aqueous solution is formed on the second photoresist layer 15. A latent image 15b soluble in an aqueous alkaline solution is formed only on the photoresist layer 15.

After the laser exposure and before the development,
After baking at 130 ° C. for 20 minutes, the first development for developing the second photoresist layer 15 is performed with DE-3 which is an alkaline aqueous solution, and ITO is diluted with nitric acid diluted to 10% or less with pure water. Then, the intermediate layer 14 formed by the above is etched, and then the second development for developing the first photoresist layer 13 by DE-3 is performed again.

By the above development and etching, a shallow trapezoidal half groove having an opening width of 0.95 μm and a depth of 1800 ° is formed, and the opening width is 0.65 μm.
Thus, a deep trapezoidal pit having a depth of 3500 ° is formed.

Next, a description will be given of a fifth embodiment of the method of manufacturing the optical disk master and the optical disk master according to the present invention. The present embodiment is applied to an optical disk and a method for manufacturing an optical disk similar to the above-described fourth embodiment. In the description of the present embodiment, the reference numerals used in the above-described drawings are used as they are, Detailed description is omitted.

In the present embodiment, after the glass substrate 2 is cleaned, the exposed portion of the glass substrate 2 is exposed to an aqueous solution of an alkaline solution, and is a FHT-332S negative resist material.
1700 ° thick first layer by spin coating using
Is formed, and pre-baking is performed.

After the surface of the first photoresist layer 13 is reverse sputtered, ITO is applied to DC in an atmosphere of Ar and O _2.
The intermediate layer 1 which is an oxide film is formed by magnetron sputtering.
4 is formed to a thickness of 70 °.

After HMDS treatment of the surface of the intermediate layer 14,
The second photoresist layer 15 is formed by spin coating using TSMR-GP8000 which is a positive resist.
It is formed to a thickness of 700 ° and prebaked.

That is, in the present embodiment, the intermediate layer 14
Before forming the first photoresist layer 13 of the negative type,
The surface of the intermediate layer 14 is subjected to HMDS treatment before the positive photoresist type second photoresist layer 15 is formed.

Thus, the first photoresist layer 1
3. After the formation of the intermediate layer 14 and the second photoresist layer 15, laser exposure, etching and development are performed to form half grooves and pits.

More specifically, as shown in FIG. 7, the exposure intensity of the first recording light La is set to 5.0 mW and the second recording light L
b is set to 1.6 mW, and the laser beam having a linear velocity of 1.2 m / s is applied to the optical disk master 11 from the first photoresist layer 15 side to perform exposure. First recording light La
As a result, as shown in FIG. 7, a latent image 13a insoluble in an aqueous alkaline solution is
A latent image 15a soluble in an alkaline aqueous solution is formed on the photoresist layer 15 of the above, and a latent image 15b soluble in an alkaline aqueous solution only on the second photoresist layer 15 is formed by the second recording light Lb. It is formed.

After the laser exposure and before the development,
After baking at 130 ° C. for 20 minutes, the first development for developing the second photoresist layer 15 is performed with DE-3 which is an alkaline aqueous solution, and ITO is diluted with nitric acid diluted to 10% or less with pure water. Then, the intermediate layer 14 formed by the above is etched, and then the second development for developing the first photoresist layer 13 by DE-3 is performed again.

By the above development and etching, a shallow trapezoidal half groove having an opening width of 0.95 μm and a depth of 1770 ° was formed, and the opening width was 0.67 μm.
As a result, a deep trapezoidal pit having a depth of 3470 ° is formed.

<Experimental Example 7> First negative type on a glass substrate
, A photoresist layer, an intermediate layer, and a positive second photoresist layer were sequentially formed, and the shapes of pits and half grooves were investigated. In the following description of the experimental examples,
This will be described with reference to FIG.

As shown in FIG. 7, a latent image is formed on the first photoresist layer 13 and the second photoresist layer 15 by the first recording light La.

The first photoresist layer 13 is formed of a negative photoresist material.
5, the latent image portion 13a of the first photoresist layer 13 is formed of a positive photoresist material.
It is insoluble in the alkaline aqueous solution, and the latent image portions 15a and 15b of the second photoresist layer 15 are soluble in the alkaline aqueous solution. Since an alkaline aqueous solution is used for developing the first photoresist layer 13, the etching of the intermediate layer 14 which is an oxide film and the first photoresist layer 13
Is developed, a latent image 13a insoluble in an alkaline aqueous solution is formed in the first photoresist layer 13, no pattern is formed in the first photoresist layer 13, and half-groove patterning becomes possible.

Further, the latent image 15b is formed only on the second photoresist layer 15 by the second recording light Lb. Second
Since the photoresist layer 15 is formed of a positive photoresist material, the latent image portion 16b is soluble in an alkaline aqueous solution. Therefore, pit patterning becomes possible by using an alkaline aqueous solution for developing the second photoresist layer 15, an acid for etching the intermediate layer 14, and an alkaline aqueous solution for developing the first photoresist layer 13.

As described above, since the first photoresist layer 13 and the second photoresist layer 15 are exposed with the first recording light La, a half groove can be formed, and the second recording light Lb can be used to form the second groove. Since only the photoresist layer 15 is exposed, pits can be formed. Further, since the first photoresist layer 13 is formed of a negative resist material and the second photoresist layer 15 is formed of a positive resist material, the intensity of the first recording light La for forming a half groove is obtained. However, the intensity of the second recording light Lb that forms the pit is higher than the intensity of the second recording light Lb, and the width of the half groove is wider than the width of the pit. As a result, pits having different depths, half grooves, and pits wider than the half grooves can be easily formed.

<Experimental Example 8> In this experiment, the first photoresist layer 13 was formed of a negative photoresist material,
The photoresist layer 15 was formed of a positive photoresist material, and the width of the pits and half grooves were examined by changing the thickness and the refractive index of the intermediate layer 14.

Specifically, the first photoresist layer 13
Is formed using FHT-332S, which is a negative photoresist material, and the second photoresist layer 15 is formed using TSMR-8900, which is a positive photoresist material. When the widths of the pits and the half grooves when the ratio was changed were examined, the results shown in FIG. 8 were obtained.

When the thickness of the ITO as the intermediate layer 14 is 60 °
In this case, the light was transmitted too much through the ITO, and the first photoresist layer 15 was exposed even with a low exposure power, and pits could not be formed. When the thickness of the ITO, which is the intermediate layer 14, is increased, the intensity of light to the first photoresist layer 13 decreases, making it difficult to expose the first photoresist layer 13, and increasing the width of the pits.

As shown in FIG. 8, under the condition 7, when the intermediate layer 14 is formed of TiO ₂ having a high refractive index to a thickness of 70 °, the intermediate layer 14 is formed to a thickness of 80 ° by ITO under the condition 5. Although the film thickness is smaller than that when formed, the intensity of light to the first photoresist layer 13 is reduced due to the influence of the refractive index, and the first photoresist layer 13 is hardly exposed, so that the bit width is increased.

The results of calculating the transmittance with respect to the exposure wavelength (λ = 458 nm) when the thickness of the intermediate layer is 0 ° to 100 ° are the same as those in FIG.
The transmittance at 60 ° is about 88%, and the transmittance at 80 ° is 84%. The transmittance when TiO ₂ is 70 ° is about 80%. Therefore, the pit width can be controlled by adjusting the refractive index and the thickness of the intermediate layer 14 to make the transmittance 85% or less.

Therefore, when the refractive index of the intermediate layer 14 is increased, the reflection of light at the interface between the second photoresist layer 15 and the intermediate layer 14 is increased, and the first photoresist layer 1
Light to 3 decreases. Since the amount of light to the first photoresist layer 13 is reduced, the latent image of the first photoresist layer 13 is reduced and the alkali-soluble portion is increased, so that the width of the pit is also increased. Therefore, the width of the pit can be controlled by adjusting the refractive index of the intermediate layer 14.

When the thickness of the intermediate layer 14 is increased, the light absorbed by the intermediate layer 14 increases, and the light to the first photoresist layer 15 decreases. The amount of light to the first photoresist layer 15 is reduced, so that the first photoresist layer 15
Becomes smaller, and the portion soluble in the alkaline aqueous solution becomes wider, so that the width of the pit becomes wider. Therefore, the pit width can be controlled by adjusting the thickness of the intermediate layer 14.

<Experimental Example 9> In this experiment, the widths of pits and half grooves when the exposure sensitivity of the first photoresist layer 13 and the second photoresist layer 15 were changed were examined. Specifically, the intermediate layer 14 is formed to a thickness of 70 ° from ITO, and TSMR- is used as a highly sensitive photoresist material.
Using GP8000, the widths of the pits and half grooves when the exposure sensitivity of the first photoresist layer 13 and the second photoresist layer 15 are changed are examined as shown by conditions 5 and 8 in FIG. Was.

As can be seen from FIG. 9, when the exposure sensitivity of the first photoresist layer 13 is lower than that of the second photoresist layer 15, the first photoresist layer 1
3 requires strong light to form a latent image, it is difficult to form a latent image on the first photoresist layer 13, the portion soluble in an alkaline aqueous solution is widened, and the width of a pit is also widened.

As a result, the width of the pit can be controlled by changing the exposure sensitivity of the first photoresist layer 13 and the second photoresist layer 15.

<Experimental Example 10> In this experiment, an experiment for forming a stamper from an optical disk master was performed. In order to form a stamper, the master optical disc must be formed into a stamper, and the first and second photoresist layers on the surface of the stamper and the intermediate layer as an oxide film must be removed.

Therefore, in this experiment, the first photoresist layer is dissolved by IPA (isopropyl alcohol) and then removed by washing with water, UV / O ₃ irradiation, and washing again with water. In the UV / O ₃ irradiation, the first photoresist layer is efficiently decomposed by ozone by irradiating ultraviolet rays UV in oxygen O ₂ and converting oxygen to ozone O ₃ .

Next, the intermediate layer, which is an oxide film, is dissolved in an acid and then removed by washing with water. This acid differs depending on the oxide film forming the intermediate layer. For example, in the case of ITO, dilute hydrochloric acid is used, and in the case of SiO ₂ , dilute hydrofluoric acid is used.

Finally, a second photoresist layer is formed on the first photoresist layer.
Is removed by the same method as that of the photoresist layer.

As described above, when cleaning the stamper for an optical disc, the surface of the stamper is cleaned in the order of etching of the first photoresist layer, etching of the intermediate layer made of an oxide film, and etching of the second photoresist layer. An optical disk stamper having different pits and half grooves can be easily obtained.

As described above, the invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications may be made without departing from the gist of the invention. It goes without saying that it is possible.

[0157]

According to the method of manufacturing an optical disc master according to the first aspect of the present invention, the adhesion between the intermediate layer and the second photoresist layer can be improved, and the development of the second photoresist layer can be improved. In addition, the second photoresist layer can be prevented from peeling off from the intermediate layer.

According to the method of manufacturing an optical disk master of the second aspect of the present invention, the adhesion between the first photoresist layer and the intermediate layer can be improved. Peeling of the layer can be prevented.

According to the method for manufacturing an optical disc master of the invention, since the baking is performed after the exposure, the adhesion of each layer can be improved without lowering the exposure sensitivity of the photoresist. Each layer can be prevented from peeling off during development.

According to the method of manufacturing an optical disc master according to the present invention, by adjusting the exposure sensitivity of the first photoresist layer and the second photoresist layer, trapezoidal pits having different depths can be formed. A half groove can be easily formed, and generation of a step of a pit can be prevented.

According to the fifth aspect of the present invention, both the first and second photoresist layers are exposed to the first recording light having a high exposure intensity to form pits having a large depth. Is formed, and only the second photoresist layer is exposed by the second recording light having a low exposure intensity to form a shallow half-groove. Since the exposed portion is soluble in an aqueous alkaline solution, the half-groove is formed. Also, wide pits can be easily formed.

According to the method of manufacturing an optical disc master according to the present invention, pits are formed by the first recording light for exposing both the first photoresist layer and the second photoresist layer, and the second pit is formed. The pits having different depths and the half grooves can be easily formed by forming a half groove with the second recording light for exposing only the photoresist layer, and the pits are wider than the half groove and have no steps. Can be formed.

According to the method of manufacturing an optical disk master according to the present invention, both the first and second photoresist layers are exposed by the first recording light having a high exposure intensity, and the second photoresist layer is exposed. Is exposed by the second recording light having a low exposure intensity. However, since the first photoresist layer is a negative photoresist and the exposed portion is insoluble in an alkaline aqueous solution, the first recording light having a high exposure intensity is used. As a result, a shallow half groove is formed, and a pit having a large depth is formed by the second recording light having a low exposure intensity. Therefore,
A pit having a width wider than that of the half groove and having no step can be easily formed.

According to the method of manufacturing an optical disk master of the invention, both the first and second photoresist layers are exposed by adjusting the refractive index and the thickness of the intermediate layer. A half groove is formed with the first recording light to be formed, and a pit is formed with the second recording light exposing only the second photoresist layer, so that trapezoidal pits and half grooves having different depths are easily formed. And a pit narrower than the half groove can be formed.

According to the ninth aspect of the present invention, it is possible to easily form a trapezoidal half groove having a small depth and pits having a large depth and a wider width than the half groove. It is possible to obtain a stable tracking and an accurate reproduction signal with respect to the wavelength.

According to the tenth aspect of the present invention, a pit having a large depth and a half groove having a small depth and a large width can be easily formed, and are stable with respect to the reproduction wavelength of the optical disk. Tracking and an accurate reproduction signal can be obtained.

According to the method of manufacturing an optical disk stamper of the present invention, in the cleaning of the optical disk stamper, the first photoresist layer is etched,
The stamper surface can be cleaned in the order of the etching of the intermediate layer and the etching of the second photoresist layer, and a stamper for an optical disc having pits and half grooves having different depths can be obtained.

According to the optical disk stamper of the twelfth aspect, in cleaning the optical disk stamper,
The surface of the stamper can be cleaned in the order of the etching of the first photoresist layer, the etching of the intermediate layer, and the etching of the second photoresist layer, and a stamper for an optical disk having pits and half grooves having different depths is provided. Obtainable.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an optical disk master to which a first embodiment of a method for manufacturing an optical disk master, an optical disk master, an optical disk stamper, and a method for manufacturing an optical disk stamper of the present invention is applied.

FIG. 2 is a diagram showing experimental results of the width of a pit and a half groove and the presence or absence of a step when the refractive index and the film thickness of an intermediate layer are changed.

FIG. 3 is a side view of the master optical disc showing a state where a step is generated at a boundary between a first photoresist layer and a second photoresist layer.

FIG. 4 is a side view of the master optical disc showing a smooth state without steps at the boundary between the first photoresist layer and the second photoresist layer.

FIG. 5 is a diagram showing the relationship between the thickness of an intermediate layer and the transmittance of a laser.

FIG. 6 is a diagram showing experimental results of the width of pits and half grooves and the presence or absence of steps when the exposure sensitivity of the first photoresist layer and the second photoresist layer is changed.

FIG. 7 is a side sectional view of an optical disk master to which a fourth embodiment of the method for manufacturing an optical disk master, an optical disk master, an optical disk stamper, and a method for manufacturing an optical disk stamper of the present invention is applied.

FIG. 8 shows a first photoresist layer of a negative type and a second photoresist layer of a positive type. The width of the pits and half grooves when the thickness and the refractive index of the intermediate layer are changed. The figure which shows an experimental result.

FIG. 9 is a view showing experimental results of pit and half groove widths when the exposure sensitivity of the first photoresist layer and the second photoresist layer is changed.

[Explanation of symbols]

 1, 11 Optical disk master 2, 12 Glass substrate 3, 13 First photoresist layer 3a, 13a Latent image portion 4, 14 Intermediate layer 5, 15 Second photoresist layer 5a, 5b, 15a, 15b Latent image portion

Claims (12)

[Claims] 1. A substrate having a thickness of 30 by spin coating.
Forming a first photoresist layer between 0 ° and 2000 °;
An intermediate layer made of an oxide film having a thickness of 50 to 300 ° is formed on the first photoresist layer by any one of a sputtering method, a vapor deposition method, and a CVD method, and further formed by a spin coating method. 300 ~ 2000Å
And a first recording light for exposing both the first photoresist layer and the second photoresist layer from the second photoresist layer side. After exposure with a second recording light that exposes only the second photoresist layer, development of the second photoresist layer, etching of the intermediate layer, and development of the first photoresist layer are sequentially performed. In the method of manufacturing an optical disk master by manufacturing the optical disk master, the surface of the intermediate layer is subjected to at least one of a reverse sputtering process and a hexamethyldisilazane process before forming the second photoresist layer. A method for manufacturing a master optical disc, comprising: 2. A substrate having a thickness of 30 by spin coating on a substrate.
Forming a first photoresist layer between 0 ° and 2000 °;
An intermediate layer made of an oxide film having a thickness of 50 to 300 ° is formed on the first photoresist layer by any one of a sputtering method, a vapor deposition method, and a CVD method, and further formed by a spin coating method. 300 ~ 2000Å
And a first recording light for exposing both the first photoresist layer and the second photoresist layer from the side of the second photoresist layer. After exposure with a second recording light that exposes only the second photoresist layer, an optical disc master is developed by developing the second photoresist layer, etching the intermediate layer, and developing the first photoresist layer. A method for manufacturing an optical disc master, comprising: performing a reverse sputtering process on a surface of the first photoresist layer before forming the intermediate layer. 3. The optical disk master according to claim 1, wherein baking is performed at a temperature of 120 ° C. or more after the exposure and before developing the second photoresist layer. Production method. 4. The method according to claim 1, wherein the exposure sensitivity of the first photoresist layer and the exposure sensitivity of the second photoresist are made different from each other to change an allowable range of the intensity of the second recording light. A method for manufacturing the master optical disc according to claim 3. 5. The first photoresist layer and the second photoresist layer.
The photoresist layer is formed of a positive photoresist whose exposed part is soluble in an aqueous alkaline solution,
5. The method according to claim 1, wherein the exposure intensity of the first recording light is higher than that of the second recording light. 6. The recording medium according to claim 5, wherein the intermediate layer is formed to have a refractive index and a film thickness that allow the recording light to pass through 90% or more, and change the allowable range of the intensity of the second recording light. Method of manufacturing an optical disc master. 7. The first photoresist layer is formed of a negative photoresist whose exposed portion is insoluble in an aqueous alkaline solution, and the second photoresist layer is formed of a negative photoresist in which the exposed portion is soluble in an aqueous alkaline solution. 5. The recording medium according to claim 1, wherein the first recording light has a higher exposure intensity than the second recording light. 6. A method for manufacturing an optical disc master. 8. The recording medium according to claim 7, wherein the intermediate layer is formed to have a refractive index and a thickness that allow the recording light to pass through 85% or less, and change the allowable range of the intensity of the second recording light. Manufacturing method of optical disk. 9. An optical disk master manufactured by the method for manufacturing an optical disk master according to claim 5, wherein a first exposure pattern having a large depth is exposed by said first recording light, and 2 that the second exposure pattern having a smaller depth is exposed by the recording light and the first exposure pattern is formed by being exposed to a wider width than the second exposure pattern. The original optical disc master. 10. An optical disk master manufactured by the method for manufacturing an optical disk master according to claim 7 or 8, wherein a first exposure pattern having a small depth is exposed by said first recording light. That the second exposure pattern having a greater depth is exposed by the recording light of No. 2 and that the second exposure pattern is formed to have a width smaller than that of the first exposure pattern. The original optical disc master. 11. A method according to claim 9, wherein a Ni film is formed on the optical disk master by sputtering or vapor deposition, Ni is electroformed, and Ni is peeled off from the substrate. Etching of the resist layer,
A method of manufacturing a stamper for an optical disk, wherein the etching of the intermediate layer and the etching of the second photoresist layer are sequentially performed. 12. A method according to claim 9, wherein a Ni film is formed on the optical disk master by sputtering or vapor deposition, Ni is electroformed, and Ni is peeled off from the substrate. Etching of the resist layer,
An optical disk stamper manufactured by sequentially performing etching of the intermediate layer and etching of the second photoresist layer.