JPS62197936A - Manufacture of metal die for optical disk - Google Patents

Abstract

PURPOSE:To reduce the number of processes and to avoid the generation of warp, etc., at a metal die by using a metal soluble in an etching solution on a base body on which a resist film is formed and forming a relief pattern to the metallic base body in accordance with information signals. CONSTITUTION:A metal soluble in an etching solution used in etching process after cutting process is used as a base body 1A to which a resist film 2 is formed on the surface. Cutting is made on the resist film formed on the base body 1A to form a recessed part in which the surface of a metallic substrate is exposed by cutting. The metal on the bottom face side of the recessed part is etched to specified depth by an etching solution, and the resist film 2 remaining after etching process is removed to obtain a metal mold (stamper) 9 having desired uneven pattern only on the metallic base body 1A. Thus, conventional conductive film forming process and electrocast process can be omitted and the mold can be manufactured by small number of processes, and pattern transfer of high fidelity is made possible without causing the irregularity of thickness and warp, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing an optical disc mold for duplicating an optical disc.

[Conventional technology]

Conventionally, as a method for duplicating optical disks and other information recording media such as video disks, compact disks, recordable disks, magneto-optical disks, etc., a method has been used to reproduce unevenness with a pattern opposite to the signal pattern recorded on the recording medium. A recording and transfer resin such as an ultraviolet curing type is applied to the formed mold, and then a transparent substrate is pressed onto the surface of the mold, and the recording and transfer resin is cured to form a predetermined shape on the transparent substrate. There is a known method for forming a resin layer onto which a concavo-convex pattern is transferred.

The above-mentioned mold for recording medium duplication has conventionally been produced by the method and procedure shown in FIG. That is, first, a disk master is prepared on which a resist film 2 is formed to have a uniform thickness on a substrate IB made of glass or the like (FIG. 2 (A)), and then this disk master is driven to rotate. The resist film 2 is exposed by irradiating the laser beam 4 modulated by a predetermined information signal or tracking signal through a condensing lens 3 [FIG. 2(B)] 1. Next, the exposed master is developed. The exposed portion or the portion other than the exposed portion is removed, and bit 5 corresponding to the information signal and a group corresponding to the tracking information are created [Second
[Fig. 2 (C)], Next, a metal conductor @6 is formed as an electrode for electroforming the mold on the surface of the recorded master on the side where the concavo-convex pattern is formed [Fig. 2 (D)]. After that, a mold base material 7 is placed on the metal conductive layer 1) U6 using the metal conductive film 6 as a cathode.
After electroforming to the required thickness [Fig. 2 (E)],
By releasing the conductive material #6 from the surface of the resist film together with the electroforming #7, a predetermined mold having an inverted pattern of protrusions and recesses is obtained [FIG. 2(F)].

[Problems to be Solved by the Invention] By the way, in the conventional manufacturing method of metal molds and molds (standbars) for optical discs, the first step is as shown in FIGS. 1(A) to 1(F). There are many stampers, and it takes a long time to manufacture one stamper. Secondly, since the depth of focus depends on the thickness of the resist film, strict control of the resist (1) and (9) is required in order to set the bit depth to a predetermined value. Thirdly, the resist film is interposed on the surface of the substrate during the steps shown in FIG. 1(A) to FIG. 1(E), especially in the conductive film forming step shown in FIG. Because the resist film thickness gradually changes in the post-electroforming process shown in Figure 1 (F),
The bit edge indicated by 8 becomes blurred, and the pattern transferred to the stamper 9 changes. Fourthly, although the main body of the stamper 90 is made of the electroformed layer 7, the stress of the electroformed layer 7 causes the stamper 9 to warp, thereby impairing the flatness of the stamper 9. As a result, the thickness of the optical disc reproduced by the stamper 9 becomes uneven, making it impossible to obtain an information recording medium with good recording and reproducing characteristics.Fifth, when a backing material is bonded to reinforce the stamper 9, the stamper 9
There is a strong tendency for wrinkles to occur on the surface of the stand bar 9, especially if the stand bar 9 itself is warped.

The purpose of the present invention is to solve the problems of the prior art described above,
It is an object of the present invention to provide a method for manufacturing a mold for a recording medium, which can be manufactured with a small number of steps, has no thickness unevenness, warpage, etc., and has faithful pattern transferability.

Means for Solving Problem C] In order to achieve the above object, the present invention uses a metal that is soluble in the etching indica solution used in the etching process after the cutting process as a substrate on which a resist film is formed. The resist film formed on the substrate is cut using the resist film, and a recess is formed by cutting to expose the surface of the metal substrate, and the metal on the bottom side of the recess is etched to a predetermined depth using an etch indica solution. , the resist film remaining after the etching process is removed to obtain a mold (standbar) having a desired uneven pattern only on the metal base.

Therefore, in the manufacturing method of the present invention, a metal substrate soluble in an etching solution containing acid or alkali as a main component is used instead of the conventional glass substrate, and the conventional conductive film forming process and electroforming process are omitted. ing.

〔Example〕

FIG. 1 shows a process diagram of a method for manufacturing an optical disk mold according to the present invention.

First, a positive resist@2 is formed on the surface of the substrate IA, which has been treated to improve adhesion with the resist, by means such as spinner coating and depping [Fig.
A)) Here, one metal substrate is made of a metal that is soluble in the etching indica solution used in the subsequent process. Etch indium liquid usually consists of a liquid whose main component is an acid or an alkali, so in the case of an etch indah liquid whose main component is an alkali, the metal substrate IA is composed of a metal such as Al, sb, or Pb, and the main component is an acid or an alkali. In the case of the etching inder liquid as a component, the metal substrate 1 is made of a metal such as Fes Ni, Cus Al, sb, or PB. Therefore, the metal constituting the metal base IA is arbitrarily selected depending on the etching solution used in the subsequent process.

Next, the disk master on which the resist film 2 has been formed is driven to rotate, and the resist film 2 is irradiated with a laser beam 4 modulated by a predetermined information signal and a tracking signal through a condensing lens 3 (see FIG. 1). B)) Next, this exposed disk master is subjected to a development process to obtain a disk master in which predetermined groups and pits 5 are formed [first step
(FIG. (C)), at this time, the metal base IA is exposed at the bottom of the recess. That is, if the resist film 2 remains on the bottom surface of the recess, the metal substrate IA cannot be etched in the etching time described later. [FIG. 1(D)] At this time, the depth of the group or pit is adjusted to 1/8.1/4 of the wavelength λ of the reading laser. The depth of the groups or pits formed by etching is adjusted by controlling the etching time.

Next, when the resist film 2 on the metal substrate IA is removed in the same manner as the conventional method, a mold (stamper) 9 having a relief pattern according to the information signal on the surface is formed [Fig. 1(E)] .

In the method for manufacturing the mold described above, the number of steps is as shown in Figure 1 (A) ~
The five steps shown in FIG. 1(E) are sufficient, and the conventional conductive film forming step and electroforming step can be omitted. The pit depth is not dependent on the resist film and is easily achieved by controlling the composition of the etch indica liquid during the etching process, controlling the etching time, selecting the metal of the metal base IA, etc.

In addition, there is no process of forming a conductive film or electroformed film on the resist film as in conventional methods, so there is almost no change in the resist film thickness, so there is no drooping at pit edges, and a faithful transfer pattern can be obtained. It will be done. Furthermore, since there is no need to form a conductive film or an electroformed layer, the stamper does not warp due to plating stress, the flatness of the base itself can be ensured, and the duplicated disk does not have any thickness.
Conventionally, the thickness of the stamper was determined by the conductive film layer and the electroformed layer, and in order to increase the thickness of the stamper, it was necessary to increase the size of the conductive film layer and the electroformed layer, and the process of forming these layers was required. It takes a lot of time.

Therefore, conventionally, when reinforcing a stamper, a backing material is bonded. However, in the present invention, the metal substrate 1
The thickness of the stamper itself can be set to a thickness that corresponds to the strength of the final stamper, which eliminates the trouble of daringly joining the backing material, and also eliminates harmful effects such as wrinkles on the stamper that occur when the backing material is joined. can be prevented from occurring.

[Effects of the Invention] As described above, according to the present invention, a metal soluble in an etch indica liquid is used for the substrate on which a resist film is formed, and a relief pattern is formed in accordance with the information signal on this metal substrate, so that conductive The film forming step and the electroforming step can be omitted, and since these steps can be omitted, it is possible to avoid warping or the like in the mold (stamper) due to plating stress. Further, since the depth of the pit does not depend on the thickness of the resist film, a desired pattern can be obtained without sagging at the pit edges without requiring strict control of the resist film thickness. Furthermore, there is no need to bond a backing material to reinforce the mold.

[Brief explanation of drawings]

FIGS. 1(A) to (E) are process diagrams showing a method for manufacturing a mold for an optical disk according to the present invention, and FIGS. 2(A) to (F) show a conventional method for manufacturing a mold for a recording medium. It is a process diagram. IA...metal base, IB...substrate (glass) 2...resist film, 3...
... Condensing lens, 4... Laser light,
5... pit, 6... conductive film layer,
7...Electroformed layer, 8...Pit edge, 9...Mold (stamper). Figure 1 Figure 2 (F) 8-day procedural amendment band (voluntary) April 7, 1985

Claims (3)

[Claims] (1) A step of cutting a resist film formed on the surface of a substrate made of a metal soluble in an etching solution, and a recessed part where the substrate surface is exposed by the cutting step is cut to a predetermined depth with an etching solution. 1. A method for manufacturing a mold for an optical disk, comprising the steps of: etching the resist film; and removing the resist film remaining after the etching step. (2) In claim (1), the etching solution contains an alkali as a main component, and the substrate is made of Al, S,
1. A method for manufacturing a mold for an optical disc, characterized in that the mold is made of a metal selected from the group consisting of Pb and Pb. (3) In claim (1), the etching solution contains acid as a main component, and the substrate is made of Fe, Ni, or C.
1. A method for producing a mold for an optical disc, characterized in that the mold is made of a metal selected from the group consisting of u, Al, Sb, and Pb.