JP3485492B2 - Method and apparatus for producing optical disk master - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical disk master.

[0002]

2. Description of the Related Art A process for producing an optical disc master is called mastering, and in this process, a metal master such as nickel called a stamper is finally produced. This stamper is used as a mold in a later molding process to produce a large number of disk replicas. The conventional mastering process is
A signal-modulated laser is exposed on a glass substrate coated with photoresist, and then a developing solution is applied on the glass substrate to etch the exposed portion, and a fine uneven pattern called a pit is formed on the photoresist. It was done by forming.

In the above method, since the pattern of the laser beam exposed during recording has a Gaussian distribution,
The sidewalls of the resulting uneven pits also have to be inclined to some extent. The sidewall angle of the pit is also affected by the residual film characteristics of the photoresist. Recently, some of the residual film characteristics have a large γ value, and it has become possible to process steep sidewalls of pits.

FIG. 8 shows a conventional processing method by dry etching. In FIG. 8A, a photoresist is applied from the resist nozzle 12 onto the substrate 11 and a resist film 13 is obtained by spinning. In FIG. 8B, the laser beam 4 modulated by the signal to be recorded is narrowed down to a submicron size by the recording lens 5, and the rotating base resist film 13 is exposed.

In FIG. 8C, the developing solution is applied from the developing nozzle 14 inside the developing device to dissolve the exposed portion and the opening 1
Get 5. In this example, a positive photoresist is used. In FIG. 8D, dry etching is performed using the photoresist having the above-described openings as a mask to form pits 16 in the substrate.

Next, the resist film on the substrate is removed, and the structure shown in FIG.
A substrate 11 processed as shown in (e) is obtained. Figure 8
In (f), the surface of the substrate 11 is made conductive by a method such as sputtering or electroless plating to form a conductor film 17. In FIG. 8 (g), the nickel thick film 18 is formed by electroforming.
To form.

In FIG. 8 (h), the nickel thick film 18 is peeled from the substrate 11 to obtain a metal master 19.

[0008]

As described above, the conventional manufacturing method uses the resist film 13 after development as an etching mask. In this method, both the power of the exposing laser and the development time determine the size of the opening. FIG. 9 shows a progress state when the laser exposure portion is melted in the developing process. In the case of a positive type resist, a portion exposed to laser is melted by a developing solution to form a pit opening. Lines S1, S2, S3, S4, S in the figure
5 shows a cross section of the melting process, and the resist film 13 is S
Dissolution proceeds in the order of 1 to S5.

Since the melting of S1 to S5 proceeds in a short time, it is difficult to accurately control the stop point, and it is very difficult to always obtain a constant shape. As can be seen from the figure, there is a problem in that the size of the opening changes greatly due to variations in the end of development, and when the resist film is used as an etching mask, the size of the mask part that requires precision becomes unstable. .

An object of the present invention is to provide a manufacturing method by which the size of the opening of the mask can be stably obtained.

[0011]

In the manufacturing method of the present invention, the method of forming pits by etching is the same as in the conventional example, but the film used as the mask is not a photoresist but an opening is formed at the time of laser exposure. It is characterized in that it is manufactured by using the material. In the present invention, if the laser power during recording is controlled to be constant, an opening of the same size can be obtained at all times, and it is not a method of obtaining an opening by dissolving a film with a chemical solution like development. The size of the opening of the mask can be stably obtained.

[0012]

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An optical disk master manufacturing method according to claim 1 of the present invention is a method for manufacturing a master disk which serves as a mold for molding an optical disk, which comprises a step of forming a recording film on a substrate. A step of forming a protective film having an etching rate lower than that of the recording film on the recording film, and a laser beam modulated corresponding to a signal to be recorded on a substrate on which the recording film is formed is focused and exposed. Then, a step of simultaneously forming an opening in the protective film and the recording film, a step of forming a pit in the substrate by etching through the opening, and a step of removing a portion which has been an etching mask during etching after the etching step And a step of making the surface of the substrate, from which the recording film has been removed, electrically conductive, and a step of subjecting the substrate having the electrically conductive surface to electroforming to produce a master. To.

According to the structure of the first aspect , the recording film thinly overcoated with the protective film is melted together with the protective film by the focused irradiation of the laser, and the opening is formed. Since the mask could do is covered with an etching-resistant highly protective film, it increases resistance during etching. This
According to the above configuration, the substrate can be etched to a desired depth even when a recording film having poor etching resistance is used as an etching mask.

[0015]

[0016]

A method of manufacturing an optical disk master according to a second aspect of the present invention is a method of manufacturing a master used as a mold for molding an optical disk, wherein a recording film is formed on at least a surface of a conductive base. A step of forming a protective film having a lower etching rate than the recording film on the recording film, and a laser modulated corresponding to a signal to be recorded on a base on which the recording film and the protective film are formed. A step of converging and exposing a beam to simultaneously form openings in the recording film and the protective film,
A step of opening a pit on the surface of the substrate by etching through the opening, a step of removing a portion which was an etching mask at the time of etching after the etching step, and a peeling treatment on the surface of the substrate from which the recording film has been removed. It is characterized in that it comprises a step of applying and a step of producing a master by subjecting the substrate subjected to the peeling process to electroforming.

A method of manufacturing an optical disk master according to a third aspect of the present invention is a method of manufacturing a master used as a mold for molding an optical disk, wherein a recording film is formed on at least a conductive base. A step of forming a protective film having a lower etching rate than the recording film on the recording film, and a laser modulated corresponding to a signal to be recorded on a base on which the recording film and the protective film are formed. A step of converging and exposing a beam to simultaneously form openings in the recording film and the protective film,
A step of forming a pit on the surface of the substrate by etching through the opening, a step of removing a portion which was an etching mask at the time of etching after the etching step, and an electroforming treatment on the substrate from which the recording film is removed. And a step of producing a master.

An optical disk master according to claim 4 of the present invention
In the manufacturing method according to any one of claims 1 to 3 , in the step of converging and exposing a signal-modulated laser to record a signal on a substrate, a reproducing laser is formed in an opening formed by the laser immediately after recording with the laser beam. It is characterized by irradiating a beam and monitoring the recorded signal. Claiming the invention
The method for producing an optical disk master according to claim 5,
In the item 3 , in the step of converging and exposing a laser beam corresponding to a signal to be recorded to form an opening, a reproducing laser for reading the width of the formed opening is irradiated separately from the recording laser. The width of the opening obtained by monitoring and reproducing from the reproduction laser is compared with a set reference width, the power of the recording laser is controlled by the difference signal, and the width of the recorded opening is kept constant. characterized in that that control to.

An optical disk master according to claim 6 of the present invention
The manufacturing method according to any one of claims 1 to 4 , wherein in the step of forming the opening by converging and exposing the laser light modulated corresponding to the recording signal, the opening formed separately from the recording laser is used. The duty of the reproduction signal is obtained by irradiating a reproduction laser for reading the unevenness of the signal as a signal and binarizing the waveform of the signal read by the reproduction laser, and the duty of the recording signal is adjusted so that the duty becomes a desired value. It is characterized by controlling.

An optical disk master according to claim 7 of the present invention
The manufacturing method is as described in claim 4 to claim 6, wherein the thickness of the recording film formed on the substrate is ((1/4) + (n / 2)) when the wavelength of the reproducing laser is λ. λ where n is a positive integer including zero (= 0, 1, 2,
3, ...)).

An optical disk master according to claim 8 of the present invention
The manufacturing method is, in claim 1, claim 2 to claim 6 ,
Formed on the substrate (recording film thickness + protective film thickness)
Where λ is the wavelength of the reproducing laser ((1/4) + (n / 2)) · λ where n is a positive integer including zero (= 0, 1, 2,
3, ...)).

An optical disk master manufacturing apparatus according to claim 9 of the present invention is an apparatus for manufacturing a master disk which serves as a mold for molding an optical disk, and is formed on a recording film formed on a base or a base. A recording exposure means for converging and exposing a recording laser modulated corresponding to a signal to be recorded on the recorded recording film and a protective film formed on the recording film, and the recording laser is formed by the exposure of the recording laser. The power of the recording laser is controlled by comparing the monitor width for irradiating and monitoring the reproduction laser for reading the width of the opening with the width of the opening obtained from the reproduction signal by the reproduction laser and the set reference width. And a control means for controlling the operation.

Hereinafter, the manufacturing method of the present invention will be described based on specific embodiments. (Embodiment 1) FIGS. 1A to 1H show manufacturing steps of (Embodiment 1) according to the manufacturing method of the present invention.
First, in FIG. 1A, a recording material is applied from a nozzle 2 to a rotating base 1 and a recording film 3 is obtained by spinning.

Next, in FIG. 1B, a laser 4 corresponding to a recording signal is narrowed down to a submicron size by a recording lens 5, and the rotating recording film 3 is irradiated with this. The irradiated portion of the recording film 3 is ablated or melted by the heat of the laser, and the subsequent contraction forms the opening 6. The recording film 3 may be any material that contains an organic dye or the like and is melted or ablated by the heat of the laser. Specifically, examples include cyanine-based organic dyes, phthalocyanine-based organic dyes, azo-based organic dyes, and the like.

In this example, the recording film 3 is formed by coating, but a film in which a metal film such as aluminum is formed as the recording film 3 by sputtering or the like may be used. Even then,
The irradiation portion is melted or evaporated by the heat of the laser to form the opening 6. In either case, the opening 6 contracts due to surface tension during cooling, forming a raised portion around the hole. FIG. 1C shows the substrate after recording, and the mask 3a is formed on the substrate.

Next, as shown in FIG. 1D, the mask 3a
The substrate 1 is etched through to form pits 7.
As the film thickness of the recording film 3, it is necessary to take the etching ratio between the substrate 1 and the recording film 3 into consideration so that the recording film 3 remains until the pits 7 having a desired depth are formed. Substrate 1 at this time
As a method of etching, dry etching such as sputter etching, ion etching, plasma etching, reactive ion etching, and wet etching may be used.

Next, in FIG. 1 (e), the master 3 is obtained by removing the mask 3a on the base 1 from the intermediate product of FIG. 1 (d).
The removal method includes a method of applying a chemical solution that dissolves the recording film 3 and a method of removing it by ashing in a dry process, and a method suitable for the material of the recording film is selected. After that, it is the same as the conventional example shown in FIG. 8, but as shown in FIG. 1 (f), the surface of the master A is subjected to a conductive treatment to form a conductor film 8, and then as shown in FIG. 1 (g). To form a thick metal film 9 by electroforming,
Finally, as shown in FIG. 1H, the metal master 10 is obtained by peeling from the base 1.

(Embodiment 2) FIGS. 2A to 2H show the manufacturing process of (Embodiment 2) according to the manufacturing method of the present invention. In this example, the base 21 has conductivity. Alternatively, a conductive film may be formed on the surface by sputtering or the like.

In FIG. 2A, the substrate 2 having conductivity is shown.
1 (a) to (Embodiment 1) on the surface of FIG.
A recording film is formed in the same manner as in (d) and ablated or melted by the heat of the laser, and the mask of the recording film is removed.
In FIG. 2E, the surface of the master A after etching is subjected to a peeling treatment to form a peeling film 23. The release film is preferably an oxide, and there is a method of forming an oxide film by oxygen radical by wet treatment with chromate or ashing method of dry treatment. In the peeling treatment, a thin film is provided as a separation layer so that the metal thick film formed by electroforming after this can be easily peeled from the conductive substrate, and a method suitable for the material of the substrate is selected.

Depending on the substrate material, there is a case where the release film need not be provided. Specifically, when a nickel metal thick film is formed on a substrate such as a molded plate of amorphous carbon, a peeling film is not necessary. Next, as shown in FIG. 2F, a metal thick film 24 is formed by electroforming, and the peeling film 2 is formed.
The metal master disk 25 is obtained by peeling the metal master disk 3 through.

In this method, since the substrate itself is conductive, it is not necessary to form the conductor film 8 by conducting the conductive treatment by sputtering etc. as shown in FIG. 1 (f) of the first embodiment. (Embodiment 3) FIG. 3 shows (Embodiment 3) of the present invention. As shown in (a), a recording material is applied from a nozzle 2 to a rotating base 1, and a recording film 3 is obtained by spinning.

Next, as shown in (b), a protective film 50 is attached on the recording film 3. The recording film 3 and the protective film 50 may be applied by a spin method, or may be applied by a dry process such as vapor deposition or sputtering. As the protective film 50 having an etching rate lower than that of the recording film 3, an ITO film, an oxide film such as silicon oxide, or a metal film may be used. The thickness of the protective film 50 is several hundreds of angstroms or less, but a thickness is selected so that it can be easily melted to form an opening at the time of laser recording in a later step and the etching resistance can be maintained.

Then, as shown in (c), the laser 10 corresponding to the recording signal is applied to the recording film 3 which is rotated by the recording lens 5 so as to stop at a size of submicron. The irradiated portions of the protective film 50 and the recording film 3 are ablated or melted by the heat of the laser,
The subsequent contraction forms the opening 6. The recording film 3 may be any material that contains an organic dye or the like and is melted or evaporated by the heat of the laser. Generally, the opening 6 contracts due to surface tension during cooling, forming a raised portion around the hole. (D) shows the base after recording. A mask 3a is formed on the base.

Next, as shown in (e), the substrate 1 is etched through the mask 3a to form pits 7. As the etching method, sputter etching, ion etching, plasma etching, dry etching such as reactive ion etching, or wet etching may be used. Opening of the mask 3a and the surrounding raised portion 3
The dimension of b determines the pit shape to be etched.

In the illustrated example, the protective film 50 is removed by etching, and the recording film 3 is also scraped off. However, due to the effect of the protective film 50, the etching selection ratio can be increased, and the mask 3a is not removed earlier than the substrate 1 as in the case of the first embodiment. Next, as shown in (f), the mask 3a on the base 1 is removed to obtain a processed master. As a removing method, there are a method of applying a chemical solution that dissolves the recording film and a method of removing it by ashing of a dry process. A method suitable for the materials of the protective film 50 and the recording film 3 is selected. After that, as in (Embodiment 1), as in (g), the surface of the master is subjected to a conductivity treatment to form the conductor film 8. Next, as shown in (h), a thick metal film 9 is formed by electroforming, and as shown in (i), the substrate 1 is formed.
Then, the metal master 10 is obtained.

(Embodiment 4) FIG. 4 shows (Embodiment 4) of the present invention. In this example, the base 21 has conductivity as in the case of the second embodiment. Alternatively, a conductive film may be formed on the surface by sputtering or the like. A step of forming a recording film on the surface of (a), a step of forming a protective film of (b), a step of recording with a laser of (c),
A step of forming the pit 22 by the etching of (d),
The process up to the step (e) of removing the mask of the recording film is the same as in FIG.

In FIG. 4F, the surface of the substrate after etching is subjected to a peeling treatment to form a peeling film 23. Release film 2
Oxide 3 is preferable, and there is a method of forming an oxide film by oxygen radical by ashing method of dry treatment or wet treatment with chromate. In the peeling treatment, a thin film is provided as a separation layer so that the metal thick film formed by electroforming after this can be easily peeled from the conductive substrate, and a method suitable for the material of the substrate is selected.

Further, depending on the material of the substrate, it is not necessary to provide a peeling film. Specifically, when a nickel metal thick film is formed on a substrate such as a molded plate of amorphous carbon, a peeling film is not necessary. Next, as shown in (g), a metal thick film 24 is formed by electroforming, and as shown in (h), a metal master 25 is obtained by peeling through the peeling film 23.

In this method, since the substrate 21 itself is conductive, it is not necessary to subject the substrate to conductive treatment such as sputtering as in the third embodiment. Also in FIG. 4 (Embodiment 4), since the protective film 50 enhances the etching resistance at the time of etching, the substrate can be surely etched. (Embodiment 5) FIG. 5 shows a manufacturing apparatus according to (Embodiment 5).

This manufacturing apparatus and the manufacturing apparatus according to (Embodiment 6) shown below are composed of the substrate 1 on which the recording film 3 is formed according to the above (Embodiment 1), and the recording film 3 according to (Embodiment 2). Of the substrate 21 on which the recording film 3 and the protective film 50 are formed by the (embodiment 3), and the substrate 21 on which the recording film 3 and the protective film 50 are formed by the (embodiment 4) It can be used for recording on any of the base recording films 3, and here, the case of recording on the substrate 1 on which the recording film 3 is formed according to (Embodiment 1) will be described as an example. .

In FIG. 5, the base 1 is a rotary drive member 35.
Is rotated at a desired rotation speed. The recording laser beam 4 is incident on the recording lens unit 31 via the epi-illumination mirror 30 and is focused to a submicron size. The recording laser beam 4 irradiated on the substrate 1 forms an opening 6. In this example, a reproduction laser beam 32 is emitted from a reproduction laser (not shown), reflected by an epi-illumination mirror 33, and incident on a reproduction lens unit 34. The reproduction beam 32 that is narrowed down to an appropriate size by the reproduction lens irradiates the opening 6 formed by the recording beam 4, and the reflected light is diffracted and interferes in phase in the opening 6.

The reflected light undergoes a modulation corresponding to the concave-convex pattern of the opening 6, is reflected by the epi-illumination mirror 33, and returns to the original optical path. This reflected light is converted into an electric signal by a photodetector, and the recorded signal can be reproduced and monitored by demodulating the signal. Since recording and playback can be checked at the same time, it is possible to detect missing signal systems and signal waveforms. Further, the shape of the opening 6 can be inferred from the level and frequency characteristics of the reproduction signal, a shape defect can be detected, and feedback to the recording optical system can be performed to maintain ideal recording conditions.

(Embodiment 6) In the manufacturing apparatus shown in FIG. 6, the substrate 1 is rotated by the rotary drive member 35, and the recording beam 4 is irradiated by the recording lens unit 31 to form an opening on the substrate. Further, the reproduction lens unit 34 irradiates the reproduction beam 32 to reproduce the signal of the opening portion in real time.

The recording lens unit 31 and the reproducing lens unit 34 can be moved in the radial direction of the base 1 by a linear motor 37. A head feed control system 38 controls the linear motor 37. The rotation driving member 35 is controlled by the rotation control system 36. The signal source 43 generates a signal containing the content to be recorded. The system control system 41 controls the reproduction optical system 40, the recording optical system 39, the head feed control system 38, the rotation control system 36, and the signal source 43 to manage and operate the entire system.

The recording optical system 39 is a recording laser, an optical modulator,
An optical system including optical components such as a lens and a laser power control member. The reproduction optical system 40 is an optical system including a reproduction laser, optical components such as a lens, and a photodetector, and converts the reflected light into an electric signal by the photodetector and outputs a reproduction signal. The reproduction signal is a signal obtained by electrical conversion of the reflected light that has been diffracted and interfered by the opening processed in the base 1, and includes shape information of the opening. The width of the opening formed by the recording laser is
The larger the power of the recording beam, the larger the power. Therefore,
The comparison circuit 42 compares the average output level of the reproduction signal with the output level when the width of the opening is optimum, and the difference output is fed back to the recording optical system 39 to control the power of the recording beam 4 at all times. The optimum opening width can be obtained.

It is also possible to maintain the optimum state of the recording signal from the phase information of the waveform of the reproduction signal. It will be described with reference to FIGS. 6 and 7. FIG. 7A shows a recording signal waveform 44, which is transmitted from the signal system 43 to the optical modulator of the recording optical system 39. FIG. 7B shows a reproduced signal waveform 45, and FIG. 7C.
Is a signal waveform 46 in which a value greater than the zero level of the reproduced signal waveform 45 is binarized to 1 and a value smaller than the zero level is binarized to zero.
Is.

The reproduction signal 45 from the reproduction optical system 40 is input to the comparison circuit 42 to generate the binarized signal waveform 46. Two
The ratio of the time a ′ of 1 and the time b ′ of zero of the binarized signal is calculated,
The ratio is compared with an ideal ratio, and the difference is input to the signal source 43 to control the ratio between the time a and the time b of the recording signal waveform 44. By controlling the closed loop in this way, the reproduction signal 2
The duty ratio (a 'vs b') of the binarized signal waveform 46 can be maintained at an ideal value. The ideal ratio referred to here is a condition under which the reproduction signal of the disc finally made from the master becomes ideal.

In the above invention, R having an information pit in advance is used.
Although the OM type disc has been described, the same applies to a write-once or erasable disc in which only grooves are provided in advance. When reading the opening immediately after recording with the reproducing laser, the recording film provided with the opening has a depth of the opening, that is, a thickness of the recording film when the wavelength of the reproducing laser is λ ((1 / 4) + (n / 2))
If λ 2, the reproduction signal output that receives phase interference due to the opening becomes maximum, and a reproduction signal with good S / N can be obtained. However, n is a positive integer including zero (=
0, 1, 2, 3, ...). The minimum film thickness of the recording film in this case is 1/4 of the reproduction laser wavelength.

Here, the case where only the recording film is ablated to form the opening, but when the protective film and the recording film are ablated to form the opening, (the thickness of the recording film is + (Thickness of protective film) is ((1/4) + (n / 2)) · λ, the reproduction signal output that receives the phase interference due to the opening becomes maximum, and the reproduction signal with good S / N is obtained. Obtainable.

In each of the above embodiments, the method of applying the recording film or the protective film by the spin method has been described, but the recording film may be formed by a method such as vapor deposition.

[0052]

The present invention has the following effects as described above. (1) Since a hole is directly formed on the substrate by a recording laser, a developing process unlike the conventional photoresist film is unnecessary. (2) Further, if a conductive substrate is used, it is not necessary to make the surface conductive by sputtering or the like before electroforming. (3) For the above reason, the metal master can be easily manufactured in a short time, and the developing device and the sputtering device are not required, so that the material cost and the capital investment can be reduced. (4) Since the reproduction signal reflected from the opening formed at the time of recording can be read in real time, it is possible to detect a signal dropout, defective opening shape, adhering foreign matter, and the like. (5) In addition, the reproduction signal of the opening formed during recording is set to 2
By digitizing, the reproduction signal duty is calculated,
A signal having an ideal duty can be recorded by controlling the duty of the recording signal on the basis of the duty. (6) In the conventional example, the step of determining the width dimension of the opening is a recording step and the developing step, but in the method of the present invention, the step of determining the width of the opening is only the recording step. It suffices to manage the laser power, and it is easy to realize a constant aperture width. (7) In the method of forming pits by etching through a mask, by providing a protective film on a mask having a high etching rate, the etching selection ratio can be increased.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of steps in (Embodiment 1) of the present invention

FIG. 2 is a process explanatory diagram in (Embodiment 2) of the present invention.

FIG. 3 is a process explanatory diagram in (Embodiment 3) of the present invention.

FIG. 4 is a process explanatory diagram in (Embodiment 4) of the present invention.

FIG. 5 is a configuration diagram of a manufacturing apparatus according to (Embodiment 5) of the present invention.

FIG. 6 is a configuration diagram of a manufacturing apparatus according to (Embodiment 6) of the present invention.

FIG. 7 is a diagram showing a signal duty according to (Embodiment 6) of the present invention.

FIG. 8 is a process explanatory diagram in a conventional example.

FIG. 9 is a diagram showing the progress of etching in a developing process in a conventional example.

[Explanation of symbols] 1 foundation 2 nozzles 3 recording film 4 recording laser 5 recording lens 6 openings 7 pits 8 Conductor film 9 Metal thick film 10 metal master 21 foundation 22 pits 23 Release film 24 Metal thick film 25 metal master 30 Recording beam epi-illumination mirror 31 Recording lens unit 32 playback beam 33 Reflection beam epi-mirror 34 Playback lens unit 35 rotary drive member 36 Rotation control system 37 linear motor 38 Head feed control system 39 Recording optical system 40 Playback optical system 41 System control system 42 Comparison circuit 43 signal source 50 Protective layer

Continuation of the front page (56) Reference JP-A-2-79236 (JP, A) JP-A-8-241541 (JP, A) JP-A-5-12722 (JP, A) JP-A-9-212923 (JP , A) JP-A-7-1461 (JP, A) JP-A-9-180272 (JP, A) JP-A-8-30973 (JP, A) JP-A-53-124404 (JP, A) JP-A- 8-45119 (JP, A) JP 5-325190 (JP, A) JP 3-238633 (JP, A) JP 1-251348 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 7/26

Claims (9)

(57) [Claims] 1. A method for producing a master disk which is a mold for molding an optical disc, comprising a step of forming a recording film on a substrate, and an etching rate higher than that of the recording film on the recording film.
Corresponding to the process of forming a low protective film and the signal to be recorded on the substrate on which the recording film is formed.
Concentrated exposure of the laser beam modulated by
A step of simultaneously forming an opening in the recording film, a step of forming a pit in the substrate by etching through the opening, and an etching mass at the time of etching after the etching step.
A step of removing a portion that had become a mark, a step of making the surface of the substrate from which the recording film is removed conductive, and a step of producing a master by subjecting the substrate having a conductive surface to an electroforming treatment. And a method for producing an optical disc master. 2. A method for producing a master disk which is a mold for molding an optical disk, comprising a step of forming a recording film on a base whose surface is at least conductive, and the recording film on the recording film. A step of forming a protective film having an etching rate lower than that of the recording film and the protective film by subjecting the substrate on which the recording film and the protective film are formed to a focused and exposed laser beam modulated corresponding to a signal to be recorded. A step of simultaneously forming an opening in the substrate, a step of forming a pit on the surface of the substrate by etching through the opening, a step of removing a portion that was an etching mask during etching after the etching step, and the recording film A method for producing an optical disc master, comprising a step of subjecting the surface of the removed substrate to a peeling treatment, and a step of subjecting the substrate subjected to the peeling treatment to an electroforming treatment to produce a master. 3. A method of producing a master disk which is a mold for molding an optical disk, comprising a step of forming a recording film on a base whose surface is at least conductive, and the recording film on the recording film. Than etching rate
A step of forming a low protective film, and a laser beam modulated corresponding to a signal to be recorded is focused and exposed on the substrate on which the recording film and the protective film are formed, and an opening is simultaneously formed in the recording film and the protective film. A step of forming, a step of forming a pit on the surface of the substrate by etching through the opening, and an etching mass during etching after the etching step.
A method for producing an optical disc master, which comprises a step of removing a portion that has been a dent and a step of subjecting the substrate from which the recording film has been removed to an electroforming process to produce a master. 4. A signal-modulated laser is focused and exposed on a substrate.
In the process of recording the signal, it was formed by the laser immediately after recording by the laser beam.
The signal recorded by irradiating the opening with a laser beam for reproduction was recorded.
No. 1 to claim 3, wherein the number is monitored.
The method for producing an optical disc master according to any one of 1 . 5. A laser beam corresponding to a signal to be recorded is condensed.
In the process of forming the opening by exposure, the width of the formed opening is read separately from the recording laser.
The width of the opening obtained from the reproduction signal from the reproduction laser is monitored by irradiating the reproduction laser for sampling.
Compare with the set reference width, and record with the difference signal
Control the laser power and adjust the width of the recorded aperture.
The method for producing an optical disc master according to claim 1, wherein the optical disc master is controlled to be constant . 6. A laser beam modulated corresponding to a recording signal
In the step of forming the opening by converging light exposure, the unevenness of the opening formed separately from the recording laser is removed.
Irradiating a reproduction laser that is read as a signal, and binarizing the waveform of the signal read by the reproduction laser.
The duty of the reproduction signal is calculated by
The duty of the recording signal is controlled so that it becomes a desired value.
The method for producing an optical disc master according to any one of claims 1 to 4 . 7. The thickness of the recording film formed on the substrate is reproduced.
When the laser wavelength is λ, ((1/4) + (n / 2)) · λ , where n is a positive integer including zero ( = 0, 1, 2,
3, ... Optical disk master manufacturing method according to any of claims 4 to claim 6, characterized in that) it is. 8. A device formed on a substrate ( Recording film thickness + preservation
Thickness of protective film ) Is ((1/4) + (n / 2)) · λ where λ is the wavelength of the reproducing laser , where n is a positive integer (including zero ) ( = 0, 1, 2,
3, ... Optical disk master manufacturing method according to any one of claims 1 to 6, characterized in that) it is. 9. A master disk to be a mold for molding an optical disk is produced.
A recording device formed on a substrate or formed on a substrate.
On the recording film and the protective film formed on this recording film.
Condensing and exposing a recording laser modulated according to the signal to be
And the width of the opening formed by the exposure of the recording laser.
A monitor that emits a playback laser for reading and monitors it.
And the width of the opening obtained from the reproduction signal by the reproduction laser,
The power of the recording laser is compared with the set reference width.
An optical disk master manufacturing device provided with control means for controlling.