JPH04344346A - Production of stamper for optical information medium molding - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention optically records information.
The present invention relates to a method for manufacturing a stamper for molding an optical recording medium that performs reproduction.

0002

2. Description of the Related Art Conventionally, magnetic materials such as magnetic tapes and magnetic disks, various semiconductor memories, and the like have been mainly used for recording various types of information. Such magnetic memory and semiconductor memory have the advantage of being able to easily write and read information, but on the other hand, they have the problem that the information content can be easily rewritten and high-density recording is not possible. was there.

In order to solve these problems, an optical information recording method using an optical recording medium has been proposed as a means for efficiently handling a wide variety of information, and an optical information recording carrier and recording/reproducing method for this purpose have been proposed. , a recording/playback device has been proposed. The optical recording medium as such an information recording carrier is
Generally, a laser beam is used to evaporate a part of the optical recording layer on the information recording carrier, or to cause a change in reflectance, or to cause deformation, so that information is transmitted through differences in optical reflectance or transmittance. Recording or playing back. In this case, the optical recording layer is a so-called DRAW (Direct Read After Write) medium that does not require any development treatment after information is written and can be "directly read after writing", and is capable of high-density recording. It is also possible to write additional information, so it is effective as an information recording/storage medium.

[0004] In general optical recording media, a thermoplastic resin such as polycarbonate resin or polymethyl methacrylic resin is used to transfer the uneven pattern using a stamper on which an uneven pattern corresponding to tracks and information is recorded. A groove is formed. Conventionally, for example, Japanese Patent Application Laid-Open No. 61-28
No. 4843, No. 141435 of the Japanese Utility Model Publication, and ``Key Points of Optical Disc Process Technology No.'' published by Japan Industrial Technology Center. A stamper for molding an information recording medium is manufactured by the method described in ``No. 5'' (published March 15, 1985).

Generally, as shown in FIGS. 4A to 4E, a photoresist 8 is first applied to the surface of a glass substrate 9 (see FIG. 4A), and tracking grooves are formed on the photoresist 8. ,
A glass master disk 6 is obtained by forming a fine pattern 8a of unevenness such as information pits (see FIG. 4(B)).

Next, a conductive film 11 is formed on the surface of the glass master 6.
After forming (see FIG. 4(C)), a metal film 12 is formed by electroforming (see FIG. 4(D)), and after further polishing,
These electrically conductive film 11 and metal film 12 are integrated and simultaneously peeled off from the glass master disk 6 to produce a stamper 13 for molding an information recording medium (see FIG. 4(E)).

[0007] Electroforming method
) The manufacturing process of a general stamper for molding information recording media is as described above. In particular, Figure 4 of the electroforming process
To explain (C) and (D) in detail, the conductive film 1 in FIG.
1 is formed by a method such as metal vapor deposition or sputtering in a vacuum, and the material used is silver, nickel, etc., but nickel is often used.

In the step shown in FIG. 4C, a nickel film is formed to a thickness of 500 to 1000 Å on the fine pattern 8 of irregularities such as tracking grooves and information pits by sputtering. Next, in the electroforming process shown in FIG. 4(D), the glass master 6 on which the conductive film 11 has been formed is held in a master holder, and while rotating at a rotational speed of 20 to 30 rpm, the nickel sulfamate electroforming solution is energize inside,
Electroforming is performed by depositing nickel metal on the glass master disk 6 on which the conductive film 11 has been formed.

This electroforming method will be explained using the cross-sectional view of the electroforming apparatus shown in FIG. 5. First, as shown in FIG. Using the dummy plate 14 as a negative electrode, electricity is applied in the nickel sulfamate electroforming solution 7 to deposit an oxidized layer of the nickel chip 10 on the dummy plate 14, and at the same time remove the oxidized layer of the nickel chip 10, as described above. Electrolytic cleaning of the nickel sulfamate electroforming solution 7 is performed.

Next, as shown in FIG. 5B, the conductive film 11 held by the master holder 15 is connected to the nickel chip 10 as a positive electrode and the glass master 6 on which the conductive film 11 is formed as a negative electrode. The formed glass master disk 6 is heated to 20~
While rotating at a rotational speed of 30 rpm, electricity is applied in the nickel sulfamate electroforming solution 7 to precipitate nickel metal onto the glass master disk 6 on which the conductive film 11 has been formed, thereby performing electroforming.

The master holder 15 used to hold the glass master 6 on which the conductive film 11 is formed is shown in FIG.
There are those that use an outer circumferential contact ring and those that use an inner circumferential contact ring, as shown in A) and (B). In either case, the contact ring must be made of a material with good conductivity, typically copper or stainless steel (Stainless steel).
US) thin plates were used.

However, in the above-mentioned conventional example, since a thin plate of copper or stainless steel with good conductivity is used as it is for the contact ring, nickel metal is deposited on the outer wall or even the inner wall of the contact ring. It had the following drawbacks. (1) After depositing nickel metal by electroforming, the formed metal film is polished to produce a stamper for molding information recording media. When the conductive film was removed, the conductive film peeled off, and during the polishing process, the polishing liquid entered through the peeled part and attacked the uneven fine patterns such as the tracking grooves and information pits of the information recording medium molding stamper. (2) Although we have taken the above measures by setting the diameter of the glass master in advance to about twice the diameter of the effective part (fine pattern of irregularities such as tracking grooves and information pits), unnecessary parts are Since it is trimmed and discarded during the process, electroforming efficiency is poor and economic efficiency is also poor. (3) Since the contact ring can only be used once for each electroforming process, the use efficiency and economy of the contact ring are poor.

[0013] In order to eliminate the above drawbacks, Japanese Patent Laid-Open No. 61-2
In Publication No. 48248, conductive treatment is applied to the side surfaces of the glass master disk, and a metal film is directly formed on the side surfaces of the glass master disk, so that during the polishing process, the polishing liquid enters from the peeled part, and the stamper for forming the information recording medium is heated. Countermeasures have been taken to address defects such as the erosion of fine uneven patterns such as tracking grooves and information pits.

[0014]

[Problems to be Solved by the Invention] However, in the conventional example described above, as shown in FIG. There were drawbacks such as. (1) When conducting conductive treatment using methods such as sputtering, in order to apply conductive treatment to the sides of the glass master, conductive treatment must be performed at least two times, resulting in poor work efficiency. . It is also possible to conduct electricity by utilizing the wraparound of sputtering, but since the conductive film is incomplete, it cannot be used as is. (2) Because the metal film is formed directly on the side surface of the glass master, it is extremely difficult to peel off the stamper for molding information recording media from the glass master after the polishing process, and the stamper is easily damaged. There were drawbacks.

The present invention has been made in view of the above-mentioned prior art, and after coating the side surfaces of a glass master with a conductive material, conductive treatment or electroforming is performed to coat the sides of the glass master with a metal film. By forming the stamper, it is possible to conduct electricity reliably in a single conductive treatment, and it also prevents the formation of a metal film directly on the side surface of the glass master, making the process of peeling the stamper from the glass master easier, and improving reliability. The object of the present invention is to provide a method for manufacturing a stamper for molding an optical recording medium with high performance.

[0016]

[Means for Solving the Problems] That is, the present invention is used for molding an information recording medium for recording and reproducing information by changing the optical characteristics by irradiation with a light beam, and is capable of changing optical characteristics corresponding to the information to be recorded. A conductive film is formed on the glass master disk on which the uneven pattern is formed, and then electroformed to form a metal film.The conductive film and the metal film are peeled off from the glass master disk as a whole to form a stamper. In the manufacturing method, the side surfaces of a glass master disk or a glass master disk that has been subjected to conductive treatment are coated with a conductive material, and then a metal film is formed up to the side surfaces of the glass master disk by conducting conductive treatment and electroforming or electroforming. This is a method for manufacturing a stamper for molding an optical recording medium, characterized by the following.

The present invention will be explained in detail below. Figure 1 (A
) to (C) are process diagrams showing an example of a method for manufacturing a stamper for molding an optical recording medium according to the present invention. As shown in the figure,
The method for manufacturing a stamper for molding an optical recording medium of the present invention is a glass substrate obtained by applying an ultraviolet curable resin to the surface of a glass substrate and forming a fine uneven pattern such as tracking grooves and information pits thereon. After applying a conductive treatment to the master disk 6 to form a conductive film, the side surface of the glass master disk is covered with a conductive material 1 and electroforming is performed to form a metal film 12,
A stamper is manufactured by peeling off the conductive film and metal film together from the glass master. The conductive material 1 is used to prevent a metal film from being directly formed on the side surface of the glass master, and to simplify the process of peeling off the information recording medium molding stamper from the glass master.

Another method of the present invention is that the glass master 6
After covering the side surface of the glass plate with a conductive material 1, conductive treatment is performed to form a conductive film, electroforming is performed to form a metal film 12, and the conductive film and metal film are peeled off from the glass master as one piece. The stamper is manufactured using

In the present invention, it is preferable to use metal tape, conductive resin, conductive rubber, or the like as the conductive material.

FIG. 4 is a process diagram showing a method of manufacturing a stamper for molding an information recording medium by electroforming. In the figure, 9 is a glass substrate such as blue plate glass, 8 is a photoresist for patterning on the glass substrate, and 8a is an uneven surface such as tracking grooves and information pits obtained by exposing and developing the photoresist. A fine pattern, 6 is a glass master disk obtained by forming a fine pattern of irregularities such as tracking grooves and information pits on a glass substrate, and 11 is a conductive plate for forming a metal film on the glass master disk 6 by electroforming. 12 is a metal film formed on a glass master on which a conductive film has been formed; 13 is a metal film for forming an information recording medium obtained by combining the conductive film and the metal film and simultaneously peeling them from the glass master; It's a stamper.

As shown in FIGS. 4A to 4E, a photoresist 8 is first applied to the surface of the glass substrate 9, and a fine pattern 8a of unevenness such as tracking grooves and information pits is formed thereon. By doing so, a glass master disk 6 is obtained. Next, after forming a conductive film 11 on the surface of the glass master 6,
After forming the metal film 12 by electroforming and further polishing,
These electrically conductive film 11 and metal film 12 are integrally peeled off from the glass master disk 6 at the same time to obtain a stamper 13 for molding an information recording medium. In the present invention, in the above steps, after the side surface of the glass master disk or the glass master disk that has been subjected to conductive treatment is coated with a conductive material, conductive treatment and electroforming or electroforming are performed.

FIG. 5 is a schematic cross-sectional view of the electroforming apparatus. 7 is a nickel sulfamate electroforming solution for depositing nickel metal and performing electroforming; 10 is a nickel chip for depositing a nickel metal film on a glass master plate coated with a conductive film; 14 is oxidation of the nickel chip A dummy plate is used for electrolytic cleaning of the electroforming layer and the nickel sulfamate electroforming solution, 6 is a glass master, and 15 is a master holder for holding the glass master.

In the electroforming process of the electroforming method, as shown in FIG. 5A of the electroforming apparatus shown in FIG. As a result, electricity is applied in the nickel sulfamate electroforming solution 7 to deposit an oxidized layer of the nickel chip 10 on the dummy plate 14, and at the same time, the oxidized layer of the nickel chip 10 is removed. Perform electrolytic cleaning of solution 7.

Next, as shown in FIG. 5B, the conductive film 11 held by the master holder 15 is connected to the conductive film 11 held by the master holder 15, using the nickel chip 10 as a positive electrode and the glass master 6 on which the conductive film 11 is formed as a negative electrode. The formed glass master disk 6 is heated to 20~
While rotating at a rotational speed of 30 rpm, electricity is applied in the nickel sulfamate electroforming solution 7 to precipitate nickel metal onto the glass master disk 6 on which the conductive film 11 has been formed, thereby performing electroforming.

FIG. 3 is a sectional view of the master holder, with FIG. 3(A) showing the outer circumferential contact ring and FIG. 3(B) showing the inner circumferential contact ring. In the figure, 6 is a glass master obtained by applying photoresist on the surface of a glass substrate and forming fine patterns of unevenness such as tracking grooves and information pits thereon, and 2 is a glass master holding the glass master. 3 is a holding part used for the same purpose; 5 is a conductive member for electrically connecting the glass master and the rectifier; 4 is a conductive member for electrically connecting the conductive member and the glass master. This is a contact ring for connecting to. In the present invention, in order to perform conductive treatment and electroforming or electroforming after coating the side surface of a glass master disk or a glass master disk that has been subjected to conductive treatment with a conductive material,
By applying conductive treatment to the side surfaces of the glass master disk and forming a metal film on the side surfaces of the glass master disk, the polishing liquid enters from the peeled part during the polishing process, forming the tracking groove of the stamper for molding information recording media, and forming a metal film on the side surface of the glass master disk. It does not attack fine patterns of unevenness such as pits.

[0026]

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Example 1 As shown in Figure 1, the pitch is 12 μm and the width is 3.0 μm on the surface.
An appropriate amount of ultraviolet curable resin (INC118, manufactured by Nippon Kayaku) was dropped onto the surface of a photomask (manufactured by HOYA) on which a pattern of projections and recesses with a depth of 3000 Å was formed. Next, using a glass substrate with a thickness of 10 mm and a size of 300 mm x 340 mm, the UV curable resin that had been dropped was sandwiched between the substrates, and while applying its own weight or appropriate pressure, the UV curable resin was uniformly thickened to 50 μm. Curing was performed with After curing, the photomask was removed to obtain a glass master disk 6. Next, a glass master disk 6 on which a conductive film 11 was formed by sputtering nickel to a thickness of 1000 Å
was obtained (see FIG. 1(A)).

Next, the side surface of the glass master 6 is covered with a conductive material 1.
coated with. A 100 μm thick copper foil was used for the conductive material 1, and a portion of it was fixed with an instant adhesive. In the electroforming process, the glass master 6 on which the conductive film 11 has been formed is held by the master holder 15, and is energized in the nickel sulfamate electroforming solution 7 while being rotated at a rotational speed of 20 to 30 rpm. Nickel metal having a thickness of 200 to 300 μm was deposited under conditions of an integral value of 160 to 240 AH (amp hours) to form a metal film 12 (see FIG. 1(B)).

The electroforming solution used here had the following composition. Nickel sulfamate tetrahydrate [Ni(NH2
SO3 )2 ・4H2 O]

50
0g/l boric acid [H3 BO3 ]

35-38g/l anti-pitting agent

After 2.5 ml/l electroforming, the metal film 12 was polished to a thickness of 100 to 200 μm, but since the metal film was formed up to the sides of the glass master, the polishing liquid entered and formed the information recording medium. It damages the fine uneven patterns such as the tracking grooves and information pits of the stamper. In addition, since the side surfaces of the glass master disk are covered with the conductive material 1, it is possible to prevent the formation of a metal film directly on the side surfaces of the glass master disk, and to prevent the formation of a metal film directly on the side surfaces of the glass master disk. By removing the adhesive material 1, the process of peeling off the information recording medium molding stamper from the glass master disk could be simplified. When the thickness of the stamper for molding an information recording medium was measured, the film thickness distribution was 200±5 μm in a range of 250 mm×300 mm, which was sufficient (see FIG. 1(C)).

Example 2 A glass master disk was obtained in the same manner as in Example 1. 1 nickel
By sputtering to a thickness of 000 Å, a glass master 6 on which a conductive film 11 was formed was obtained (see FIG. 1(A)).
.

Next, the side surface of the glass master 6 is covered with a conductive material 1.
coated with. For the conductive material 1, a conductive rubber made of silicon rubber or HTV rubber with a thickness of 500 μm mixed with conductive powder such as copper or black carbon was used, and a portion thereof was fixed with an instant adhesive. In the electroforming process, the metal film 12 was formed under the same conditions as in Example 1 (see FIG. 1(B)).

After electroforming, the metal film 12 is
When the glass master was polished to a thickness of μm, the process of peeling off the information recording medium molding stamper from the glass master could be simplified by removing the conductive material 1 from the side surface of the glass master. In addition, when measuring the thickness of the stamper for molding information recording media, it was found that 2.
The film thickness distribution was sufficiently good at 00±5 μm (see FIG. 1(C)).

Example 3 A glass master disk was obtained in the same manner as in Example 1. (Figure 1(A)
reference).

Next, the side surface of the glass master 6 is covered with a conductive material 1.
coated with. A 100 μm thick copper foil was used for the conductive material 1, and a portion of it was fixed with an instant adhesive. Next, add 1 nickel
A glass master disk 6 on which a conductive film 11 was formed was obtained by sputtering to a thickness of 000 Å. In the electroforming process, the metal film 12 was formed under the same conditions as in Example 1 (see FIG.
See B).

After electroforming, the metal film 12 is
When the glass master was polished to a thickness of μm, the process of peeling off the information recording medium molding stamper from the glass master could be simplified by removing the conductive material 1 from the side surface of the glass master. In addition, when measuring the thickness of the stamper for molding information recording media, it was found that 2.
The film thickness distribution was sufficiently good at 00±5 μm (see FIG. 1(C)).

Comparative Example 1 A glass master disk was obtained in the same manner as in Examples 1 and 2. Next, by sputtering nickel to a thickness of 1000 Å, a glass master disk 6 on which a conductive film 11 was formed was obtained (see FIG. 1(A)).

Next, the side surface of the glass master 6 is covered with a conductive material 1.
coated with. The conductive material 1 was coated with a conductive resin material Dotite D-362 (trade name) to a thickness of about 100 μm (see FIG. 1(B)).

After electroforming, the metal film 12 is
When the glass master was polished to a thickness of μm, the process of peeling off the information recording medium molding stamper from the glass master could be simplified by removing the conductive material 1 from the side surface of the glass master. In comparison with Example 1 and Example 2, glass master 6
Because the conductive resin material Dotite D-362 (trade name) was coated on the side surface of the stamper, it was difficult to peel off the information recording medium molding stamper from the glass master after the polishing process. Partly because of the effect of ensuring electricity supply, the film thickness distribution was very good and comparable to Example 1 and Example 2 (see FIG. 1(C)).

[0038]

[Effects of the Invention] As is clear from the above explanation, by coating the side surfaces of the glass master with a conductive material and then performing conductive treatment or electroforming to form a metal film up to the sides of the glass master, the following can be achieved. It can produce various remarkable effects. (1) Reliable energization can now be achieved with a single conductivity treatment. (2) Since a metal film is indirectly formed on the side surface of the glass master, the process of peeling off the information recording medium molding stamper from the glass master after the polishing process is very easy and may damage the stamper. Things are gone. (3) Since one contact ring can be used for electroforming as many times as desired, the contact ring is more efficient and economical to use. Furthermore, since the polishing liquid does not enter through the peeled part during the polishing process, it does not damage the fine uneven patterns such as the tracking grooves and information pits of the stamper for molding information recording media, allowing reliable and inexpensive molding of optical recording media. It is now possible to create a stamper for

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing an example of a method for manufacturing a stamper for molding an optical recording medium according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a conventional method for manufacturing a stamper for molding an optical recording medium.

FIG. 3 is a sectional view of the master holder.

FIG. 4 is a process diagram showing a method for manufacturing a stamper for molding an information recording medium by electroforming.

FIG. 5 is a schematic cross-sectional view of the electroforming device.

[Explanation of symbols]

1 Conductive material 2 Top lid 3 Holding part 4 Contact ring 5 Conductive member 6 Glass master 7 Nickel sulfamate electroforming liquid 8 Photoresist 8a Fine pattern of unevenness 9 Glass substrate 10 Nickel chip 11 Conductive film 12 Metal film 13 Information recording medium Molding stamper 14 Dummy plate 15 Master holder 16 Resin base material

Claims (2)

[Claims] 1. Used in the molding of information recording media for recording and reproducing information by changing the optical characteristics by irradiation with a light beam, a glass master disk on which a concavo-convex pattern corresponding to the information to be recorded is formed, In a method of manufacturing a stamper by performing conductive treatment to form a conductive film, performing electroforming to form a metal film, and peeling off the conductive film and metal film together from the glass master, the glass master or the conductive For forming an optical recording medium, which is characterized in that a metal film is formed up to the side surface of the glass master by coating the side surface of the treated glass master with a conductive material and then performing conductive treatment and electroforming or electroforming. Stamper manufacturing method. 2. The method for producing a stamper for molding an optical recording medium according to claim 1, wherein the conductive material is a metal tape, a conductive resin, or a conductive rubber.