JPH0648552B2 - Method for manufacturing mold for recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a recording medium mold for duplicating a recording medium such as an optical disk for recording information.

[Conventional technology]

Conventionally, as a duplication method of an optical disc represented by a video disc, a compact disc, a write-once disc, a magneto-optical disc, and other information recording media, unevenness of a pattern opposite to a signal pattern recorded on the recording medium is used. By applying a recording transfer resin such as an ultraviolet curable resin to the mold in which the transparent resin is formed, and then a transparent substrate is pressure-bonded to the surface of the mold to cure the recording transfer resin, There is known a method of forming a resin layer on which a predetermined uneven pattern is transferred on a substrate.

The above-mentioned mold for duplicating a recording medium is conventionally manufactured by the method and procedure shown in FIG. That is, first, a disk master having a resist film formed on a substrate such as glass at a uniform pressure is prepared {FIG. 7 (a)}. Then, the disk master is driven to rotate, and the disk master is irradiated with laser light modulated by a predetermined information signal or a tracking signal to expose the resist film, and the exposure master is subjected to a development treatment to expose the exposed portion or A portion other than the exposed portion is removed, and a pit corresponding to the above information signal and a groove corresponding to the above tracking information are produced (FIG. 7).
(b)}. Next, a metal conductive film is formed as an electrode for electroforming a mold on the surface of the recorded master on which the concave-convex pattern is formed {FIG. 7 (c)}. Then, as a pretreatment for electroforming, the metal conductive film is immersed in an acid treatment solution to remove oxides formed on the surface of the metal conductive film {FIG. 7 (d)}.
After that, a metal base is used as a cathode and a die base material is electroformed on the metal conductive film to a required thickness (FIG. 7 (e)). Finally, the electroconductive film and the electroconductive film are released from the surface of the resist film to obtain a predetermined mold having a concavo-convex pattern inverted (FIG. 7 (f)).

[Problems to be solved by the invention]

By the way, in this type of information recording medium, a reproducing laser beam is irradiated along the concave-convex pattern to detect the presence or absence of these pits or grooves from the difference in the reflected light intensity between the portions with and without pits or grooves. Therefore, the signal is recorded or reproduced. The difference in the reflected light intensity depends on the shape of the pit or groove (depth, size, overall shape),
In order to obtain an information recording medium having good recording / reproducing characteristics, it is necessary to manufacture a mold in which pits and grooves having a predetermined shape are precisely and uniformly formed.

However, in the mold formed as described above, conventionally,
Frequently, the metal conductive film and the electroformed film are easily separated from each other and have poor durability, or the pits or grooves having a predetermined shape cannot be transferred, and thus mass production of the information recording medium is attempted. It was a serious obstacle above.

The present inventor, as a result of pursuing the cause of such a mold defect, discovered that there is a problem with the acid treatment performed as a pretreatment for electroforming. That is, when the substrate on which the metal conductive film is formed is left to stand in the air, for example, an oxide is generated in the metal conductive film. When casting is performed, the adhesive force between the metal conductive film and the electroformed film becomes poor, making it unusable as a mold. Therefore, a pretreatment for removing the oxide is required before the electroforming step, but the conventional acid treatment is performed by immersing the substrate on which the metal conductive film is formed in a treatment solution containing a strong acid. Since the oxide formed on the surface is dissolved and removed, the treatment liquid penetrates between the metal conductive film and the resist film during the immersion. Then, after the electroformed film is formed, this treatment liquid leaches between the metal conductive film and the electroformed film, or the electroformed film is peeled off,
We learned that cracks, pinholes, etc. were generated, which hindered the formation of accurate uneven patterns.

[Means for solving problems]

The present invention prevents oxides formed in the metal conductive film by storing the substrate on which the metal conductive film is formed in a non-oxidizing atmosphere and removes the oxides. It is intended to prevent the inconvenience as described above by omitting the pretreatment of (1).

〔Example〕

FIG. 1 shows a process diagram of a method for manufacturing a recording medium mold according to the present invention.

First, as shown in FIG. 2, the surface of the substrate 1 made of glass or the like that has been subjected to a treatment for improving the adhesiveness with the resist is removed from an ultraviolet curable synthetic resin or the like by means such as spinner coating or depping. A resist film 2 is formed {FIG. 1 (a)}.

Then, as shown in FIG. 3, the disk master 3 having the resist film 2 formed thereon is rotationally driven to form the resist film 2 on the resist film 2.
A laser beam 4 modulated by a predetermined information signal and a tracking signal is irradiated, and then the exposed disc master is developed to obtain a disc master formed with predetermined grooves and pits. Figure 1 (b)}.

Then, as shown in FIG. 4, a metal conductive film 6 such as nickel is formed on the resist film 2 of the recorded master 5 by means such as vacuum deposition, sputtering, ion plating, etc. {FIG. 1 (c)}.

Next, the disk master having the metal conductive film 6 formed thereon is cooled in a non-oxidizing atmosphere and stored until the next electroforming step {FIG. 1 (d)}. Here, the non-oxidizing atmosphere means in a vacuum, a reducing gas, or an inert gas.

Then, as shown in FIG. 5, the disk master on which the metal conductive film 6 is formed is taken out from the non-oxidizing atmosphere, and a metal mold base is immediately electroformed on the metal conductive film 6 to form the electroformed film 7. Form {Fig. 1 (e)}. In this case, it is preferable that the mold base material 7 is made of the same material as the metal conductive film 6 in order to secure the adhesiveness between them. In addition, the metal conductive film 6
The disk master on which is formed is taken out from the non-oxidizing atmosphere, and the shorter the time until the electroforming is started, the better,
2 hours of exposure to air with a temperature of 20 ° C and a humidity of 60% RH
~ Within 3 minutes is good.

Finally, the metal conductive film 6 is released from the surface of the resist film 2 together with the electroformed film 7 to obtain a mold 8 as shown in FIG. 6 {FIG. 1 (f)}.

In the die 8 thus obtained, the metal conductive film 6 is not oxidized before the electroforming of the die base material.
Since the metal conductive film 6 and the electroformed film 7 are in close contact with each other and the electroformed film 7 is not peeled off or a factor for generating a crack or a pinhole does not intrude between them, transferability and Good durability.

Example 1 A groove having a width of 0.2 μm, a depth of 700 μm, a pitch of 1.6 μm, and a width of 0.8 μm, a length of 1.3 μm, and a depth of 15
900 Å under the following conditions, on the surface of the recorded master with the pits of 00 Å cut
The nickel-made conductive film was formed.

Film forming means; temperature of the resistance heating evaporation recorded master; about 80 ° C. vacuum; Sample 1 1 × 10 ^-4 Torr Sample 2 5 × 10 ^-5 Torr Sample 3 2 × 10 ^-5 Torr Sample 4 1 × 10 ^{- 5} Torr sample 5 5 × 10 ^-6 Torr sample 6 2 × 10 ^-6 Torr sample 7 1 × 10 ^-6 Torr sample 8 5 × 10 ^-7 Torr Then, the above samples were adjusted to 1 × 10 ^-6 Torr After cooling to room temperature in a vacuum chamber and removing from this vacuum chamber,
Immediately, Nickel was electroformed.

Each of the above samples was tested for the transferability of the groove and the pit and the peelability between the conductive film and the electroformed film, and the results shown in Table 1 were obtained. Here, the mark “◯” regarding the transferability of the groove and the pit indicates that the transferability is good and the pit and the groove having a predetermined shape are formed in the mold. In addition, regarding the peelability between the conductive film and the electroformed film,
The mark indicates that they are firmly adhered to each other and is difficult to peel off, and the mark x indicates that they are easily peeled off and has no durability.

As is clear from Table-1, when a nickel conductive film is vacuum-deposited at a vacuum degree of 1 × 10 ^-4 Torr or more and cooled to room temperature in a vacuum chamber adjusted to 1 × 10 ^-6 Torr, Therefore, good transferability can be obtained. However, 5 × 10 ^-5 To
A nickel conductive film vacuum-deposited with a vacuum degree of rr or less is peeled off from the nickel electroformed film even when cooled and stored at room temperature in a vacuum tank adjusted to 1 × 10 ^-6 Torr. It was found to be easy and not durable.

Experimental Example 2 A conductive film made of nickel having a thickness of 900 Å was formed under the following conditions on the surface of the recorded master having the grooves and pits cut therein similar to those used in the first embodiment, under the following conditions.

Film-forming means: Resistance heating vapor deposition method Recorded master temperature: Approx. 80 ° C Vacuum degree: 1 × 10 ^-6 Torr Number of samples: 4 Then, cool down and store each of the above samples to room temperature under the following conditions. After taking out from this storage tank,
Nickel electroforming was immediately performed under exactly the same conditions as in the first embodiment.

Sample 1; left in the air Sample 2; stored in a vacuum chamber adjusted to 1 × 10 ^-6 Torr Sample 3; stored in a vacuum chamber adjusted to ^0.1 Torr Sample 4; stored in an argon gas chamber When the transferability of the groove and the pit and the peelability between the conductive film and the electroformed film were tested, the results shown in Table 2 were obtained. In addition, the transferability of the groove and the pit and the peelability between the conductive film and the electroformed film are evaluated.
The mark and the X mark are attached according to the same judgment criteria as in the case of the first embodiment.

As is clear from Table 2, when the nickel conductive film is vacuum-deposited at a vacuum degree of 1 × 10 ⁻⁶ Torr, good transferability can be obtained regardless of the cooling storage conditions. However, it was found that the one that was left in the air and cooled and stored was easily peeled off from the nickel electroformed film and had no durability.

〔The invention's effect〕

As described above, according to the method of the present invention, since an oxide is not formed on the metal conductive film, it is possible to manufacture a mold having excellent transferability and durability. Also,
Since a process for removing the oxide formed on the conductive film is not required unlike the conventional case, the manufacturing process of the mold is simplified and the manufacturing cost of the information recording medium as a product can be reduced. .

[Brief description of drawings]

FIG. 1 is a process explanatory view showing a mold manufacturing method of the present invention, and FIG.
The figure is a cross-sectional view of a disk master on which a resist film is formed, FIG. 3 is an explanatory view showing the cutting process, FIG. 4 is a cross-sectional view of a disk master on which a metal conductive film is formed, and FIG. 5 is a metal electroformed film. 6 is a cross-sectional view of the disk master on which the disk is formed, FIG. 6 is a cross-sectional view of the mold, and FIG. 1: substrate, 2: resist film, 3: disk master, 4: laser light, 5: recorded master, 6: metal conductive film, 7: electroformed film, 8: mold

Claims (6)

[Claims] 1. A step of cutting a resist film formed on a surface of a substrate, a step of forming a metal conductive film on a surface of an uneven portion formed by the cutting step, and a step of forming the metal conductive film. The cooled substrate in a non-oxidizing atmosphere,
A step of storing, a step of taking out the substrate on which the conductive film is formed from the non-oxidizing atmosphere and immediately electroforming a mold base material on the conductive film, and a mold formed by the electroforming step And a step of releasing the metal conductive film from the surface of the resist film together with the base material. 2. The method for manufacturing a mold for a recording medium according to claim 1, wherein the step of cooling and storing the substrate on which the metal conductive film is formed is performed in a vacuum chamber adjusted to a vacuum. A method for manufacturing a mold for a recording medium, characterized in that 3. The method for manufacturing a mold for a recording medium according to claim 1, wherein the step of cooling and storing the substrate on which the metal conductive film is formed is performed by using an inert gas injection method. A method for manufacturing a mold for a recording medium, which is carried out in an active gas tank. 4. The method of manufacturing a mold for a recording medium according to claim 1, wherein the step of cooling and storing the substrate on which the metal conductive film is formed is a reduction in which a reducing gas is injected. A method for manufacturing a mold for a recording medium, wherein the method is carried out in a reactive gas tank. 5. The method of manufacturing a mold for a recording medium according to claim 1, wherein the step of forming a metal conductive film on the surface of the uneven portion of the cut substrate comprises 2 steps.
In a vacuum chamber adjusted to a vacuum degree of ^10-5 Torr or more,
A method of manufacturing a mold for a recording medium, which is performed by a vacuum deposition method. 6. A method for manufacturing a recording medium mold according to any one of claims 1 to 5, wherein the metal conductive film and the electroformed film are formed by nickel. Mold manufacturing method.