JPH06173069A - Electrocasting device for master disk for production of stamper - Google Patents

Abstract

PURPOSE:To improve the quality and yield of a stamper for production of optical recording media by executing electrocasting by using a conducting member which is formed as a curved surface in the end part in contact with a conductive film. CONSTITUTION:This electrocasting device for the master disk for production of the stamper for forming metallic films by executing electrocasting on the conductive film 54 formed on the master disk 1 having the rugged patterns corresponding to the preformat of the optical recording medium has the conducting member 4 for energizing the conductive film 54. This conducting member 4 is formed as the curved surface gradually approaching the conductive film 54 near the end part where the conducting member 4 and the conductive film 54 come into contact. As a result, the film break of the electrocasting film in the electrocasting state for the master disk at the time of producing the stamper is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroforming apparatus for a master for manufacturing a stamper for manufacturing an optical recording medium for optically recording and reproducing information.

[0002]

2. Description of the Related Art Conventionally, magnetic materials such as magnetic tapes and magnetic disks, and various semiconductor memories have been mainly used for recording various information. Such a magnetic memory and a semiconductor memory have an advantage that information can be easily written and read, but on the other hand, there are problems that the contents of information are easily tampered with and high-density recording cannot be performed. . In order to solve such a problem, 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, a recording / reproducing method, and a recording / reproducing apparatus therefor are proposed. Has been done. The optical recording medium as such an information recording carrier is generally an optical recording medium that volatilizes a part of the optical recording layer on the information recording carrier using a laser beam, causes a change in reflectance, or causes a deformation to produce an optical recording medium. Information is recorded or reproduced by the difference in the typical reflectance or transmittance. In this case, the optical recording layer is a so-called DRAW (direct read after write) medium that can be “read directly after writing” without the need for development processing after writing information, and high density recording is possible. It is also effective as a recording / storing medium for information because it can be additionally written.

FIG. 4 shows a conventional optical recording medium (optical disc,
It is a schematic sectional drawing of an optical card. Recording / reproducing of information is performed while positioning by the phase difference of the laser light by utilizing the fine irregularities of the track groove portion 42. In the manufacture of a general optical recording medium, a polycarbonate resin or a polymethylmethacrylate resin, which is a thermoplastic resin, is used to form a concavo-convex pattern on a transparent substrate 41 by using a stamper on which a concavo-convex pattern corresponding to tracks and information is recorded. The pattern is transferred to form the track groove portion 42.
Next, the optical recording layer 43 is applied on top of it, and the spacer 4
4 and the protective substrate 46 is laminated via the adhesive layer 45 (FIG. 4A). The spacer 44 may be omitted (FIG. 4 (b)).

The stamper manufacturing method is generally as shown in FIG. That is, (a) a step of forming a resist layer 52 on a glass substrate 51 that has been polished with good flatness, and thereby forming a track groove 53, and (b) forming a conductive film 54 on the track groove 53 by sputtering or the like. A metal film is formed by the step (c) forming the electroformed film 55 on the conductive film 54 by electroforming, and the metal stamper is obtained through steps such as back surface polishing and trimming.

In the conventional electroforming method, as shown in FIG. 3, an uneven pattern (not shown) is formed on the surface,
A master 1 having a conductive film 54 formed thereon by sputtering or the like.
Is inserted into the master holder 2 and fixed by the holder lid 3. The master holder 2 has conductivity, and it is preferable to energize the conductive film 54 of the master 1 through the conductive member 4 to perform electroforming.

[0006]

However, since the conductive member 4 is pressure-bonded to the conductive film 54 by the holder lid 3, the edge of the tip 4a of the conductive member 4 causes film breakage, which makes it difficult to establish conduction. However, there was a problem that so-called film peeling occurred when this was initially peeled off. The substantial problem caused by the film peeling is that in the subsequent back surface polishing for uniform film thickness, the polishing liquid penetrates into the film breakage, the surface is contaminated, and the film peeling progresses. That is, the quality and yield of the

[0007]

The present invention has been made to solve the above problems. As a result of intensive studies to achieve the above object, the present inventors have conducted electroforming on a conductive film formed on a master having an uneven pattern corresponding to the preformat of the optical recording medium to form a metal film. An electroforming apparatus of a stamper manufacturing master for forming a film, comprising a conductive member for energizing the conductive film, wherein the conductive member is near the contact end of the conductive member and the conductive film. The inventors have found that a conductive film can be prevented from being broken by an electroforming apparatus for a stamper manufacturing master, which is characterized in that it is formed into a curved surface that is asymptotic to the above.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a partially enlarged view showing an example of the vicinity of a contact end portion between a conductive member and a conductive film of a master. That is, the master 1 having the conductive film 54 provided on the glass surface by sputtering or the like is fitted into the master holder 2 and fixed by the holder lid 3 via the conductive member 4. The holder lid 3 is provided with a taper portion 5 and a sealing material 6 in order to prevent electrodeposition on the conductive member 4 as much as possible. The master holder 2 is made of a conductive member, is electrically connected to the conductive film 54 by the conductive member 4, and is connected to a power source, so that electroforming can be performed. Further, the tip portion 4a of the contact portion of the conductive member 4 with the conductive film 54 is processed into a curved surface so that it becomes asymptotic to the conductive film 54 near the contact end portion. As a result, the edge of the tip portion 4a is eliminated, and film breakage of the conductive film 54 can be prevented.

If the tip 4a of the conductive member 4 is not processed into a curved surface, the conductive member 4 is pressed against the conductive film 54 by the holder lid 3, so that the edge of the tip 4a of the conductive member 4 causes film breakage. Is likely to occur, and in this case, it becomes difficult to establish electrical continuity, and this causes initial peeling to cause film peeling. As a substantial problem due to the film peeling, in the subsequent back surface polishing for uniforming the film thickness, the surface is contaminated by the infiltration of the polishing liquid, and the film peeling further progresses.

As the conductive member 4, a conductive plastic or the like processed into a predetermined shape can be used mainly in addition to metals such as copper, stainless steel and aluminum. Furthermore,
A deformable conductive rubber or the like may be used for at least the tip portion 4a. As a method of processing the tip portion 4a into a curved surface, for example, the edge portion may be scraped with a file or the like to form a curved surface.

An example of the electroforming apparatus used in the electroforming method of the present invention will be described with reference to FIG. The electroforming liquid 8 is pumped up from the adjusting tank 12 by the pump 13 and discharged into the electroforming tank 9 from the discharge port 14 in the direction of arrow A. This electroforming liquid flow passes through the gap between the anode 7 and the cathode 10, and then is collected in the adjusting tank 12 by the discharge pipe 15. As a result, the electroforming liquid is circulated and new electroforming liquid 8 is constantly supplied to the electroforming tank 9.

If the discharge port 14 for feeding the electroforming liquid 8 is oriented in a direction perpendicular to the surface of the cathode 10, the electroforming effect is great. However, in order to uniformly remove the hydrogen gas generated during electroforming, the angle may be changed as necessary. Alternatively, the number of discharge ports may be increased or decreased. Discharge amount of electroforming liquid 8 is 15 l / min to 300 l
/ Minute is preferable. If the flow rate is too low, a flow rate sufficient to remove the hydrogen gas on the cathode surface cannot be obtained, and if the flow rate is too high, excessive pressure is applied to the pump 13, the discharge port 14, and the like.

[0014]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 A photopolymer (manufactured by Nippon Kayaku Co., trade name INC) was mounted on a rectangular glass plate having a thickness of 10 mm, 340 mm × 300 mm.
-118) was vacuum-injected to a thickness of 80 μm, and exposed and cured by a UV exposure machine to form an uneven pattern having a groove width of 2.5 μm and a land length of 9 μm. A 1000 Å thick nickel film was formed thereon by sputtering. On the other hand, a 0.5 mm-thick copper plate was cut into a ring shape, and a contact ring along the inner periphery of which was scraped off with a curved surface was used as a conductive member. Next, the glass plate with the nickel film was inserted into a master holder, and a holder lid was attached via a contact ring. This was placed in an electroforming tank filled with the electroforming solution of the apparatus shown in FIG. 2, and electroforming was performed using the nickel film on the glass plate as a cathode and the nickel balls in a titanium basket as an anode.

500 l of an electroforming liquid having the following composition was placed in the adjusting tank 12, fed into the electroforming tank 9 by the pump 13, and returned to the adjusting tank by the discharge pipe 15 to circulate the liquid.

Nickel sulfamate (tetrahydrate) 500 g / l Boric acid 35 g / l Pit inhibitor (Hashiyo Murata Co., Ltd., trade name NP-A) 5 ml / l The electroforming solution was pH 4.2 with 1N-sulfamic acid. The liquid temperature was 45 ° C., the flow rate of the liquid discharged from the discharge port 14 was 39 l / min, and the rotation speed of the holder was 20 rpm. In addition, the current condition was that the initial current was 3 A (30 minutes), and then electroforming was performed at 50 A until the integrated current value reached 10600 A · min, and an electroformed film having a thickness of 240 μm in the central portion was obtained. After that, the holder lid was opened, the contact ring was removed, and the glass master having the electroformed film was taken out. The finished electroformed film showed no film breakage or film peeling, and was uniformly formed on the glass master.

In the same manner as above, three electroformed films were prepared,
Although reproducibility was observed, neither film breakage nor film peeling occurred.

Comparative Example 1 An electroformed film was formed on a glass master by the same method as in Example 1, using the same copper contact ring as in Example 1 as the conductive member except that the contact end was not curved and the edge was left. did. In this case, film breakage occurred at the contact end. Further, film peeling occurred from there, and the obtained stamper was defective.

[0020]

According to the present invention, electroforming is performed using a conductive member (contact ring) having a curved contact end portion with the conductive film, whereby film breakage and film peeling of the conductive film are surely prevented, It is possible to improve the quality and yield of the stamper for manufacturing an optical recording medium.

[Brief description of drawings]

FIG. 1 is a partially enlarged view illustrating an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of the electroforming apparatus of the present invention.

FIG. 3 is a schematic explanatory view showing an example of a holder for setting a master used for carrying out the present invention.

FIG. 4 is a schematic cross-sectional view showing the structure of a conventional optical recording medium.

FIG. 5 is a schematic explanatory view showing a manufacturing process of a stamper.

[Explanation of symbols]

 1 Master 2 Master Holder 3 Holder Lid 4 Conductive Member 4a Tip 5 Taper 6 Sealing Material 7 Anode 7a Metal Ball 7b Support 8 Electroforming Liquid 9 Electroforming Tank 10 Cathode 11 Motor 12 Adjustment Tank 13 Pump 14 Discharge Port 15 Discharge Pipe 16 Top Cover 41 Transparent Substrate 42 Track Groove 43 Optical Recording Layer 44 Spacer 45 Adhesive Layer 46 Protective Substrate 51 Glass Substrate 52 Resist Layer 53 Track Groove 54 Conductive Film 55 Electroformed Film

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hitoshi Yoshino 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Naoki Kushida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (1)

[Claims] 1. A stamper manufacturing master electroforming apparatus for electroforming a conductive film formed on a master having an uneven pattern corresponding to a preformat of an optical recording medium to form a metal film. And a conductive member for energizing the conductive film, wherein the conductive member is formed on a curved surface that is asymptotic to the conductive film in the vicinity of a contact end between the conductive member and the conductive film. Electroforming equipment for masters for stamper production.