JPH052780A - Stamper manufacturing method - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the warp amount of the master with stamper so that a stamper with a uniform thickness can be easily obtained. [Structure] Substrate 11 made of glass or the like that is polished with good flatness
After forming a conductive film 7 made of nickel or the like on a glass master 3 which is a master having a resin film 10 having a concavo-convex pattern formed at a predetermined depth on its surface, electroforming of nickel or the like is performed to a predetermined thickness. Then, the electroformed film 4 which is integrated with the conductive film 7 and serves as a stamper is formed. After that, the back surface of the electroformed film 4 is mirror-polished while adjusting the environmental temperature so that the warp amount of the stamped master 1 becomes equal to or less than a predetermined amount, and the stamped master (electroformed film master) 1 is obtained. Electroformed film 4 of 1
Is peeled off from the glass master 3 to obtain a metal stamper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a stamper used for molding an optical information recording medium (optical recording medium) for recording and reproducing information by changing the optical characteristics by irradiation of a light beam. Regarding

[0002]

2. Description of the Related Art Conventionally, as a means for efficiently handling a wide variety of information, an optical information recording method using an optical recording medium has been proposed, and an optical information recording carrier, a recording / reproducing method, and a recording / reproducing apparatus therefor have been proposed. There is. 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 does not require development processing after writing information,
So-called DRA that can be "read directly after writing"
Since it is a W (Direct Read After Write) medium, high density recording is possible and additional writing is possible, it is effective as a recording and storage medium of information.

In a general optical recording medium, a polycarbonate resin or polymethylmethacrylate resin, which is a thermoplastic resin, is used by using a stamper on which an uneven pattern corresponding to a track or information is recorded, and the uneven pattern is transferred to the groove portion. Is formed. Japanese Unexamined Patent Publication No. 61-284843, Japanese Utility Model Laid-Open No. 58-141435, and "Point No. 5 of optical disk process technology" (March 15, 1985)
JP, Japan Industrial Technology Center), a conventional method for manufacturing a stamper for molding an information recording medium is described.

These stampers are manufactured by forming a resin film having a concavo-convex pattern at a predetermined depth on the surface of a substrate made of glass or the like that has been polished to have a good flatness.
After forming a conductive film of nickel or the like, the liquid temperature is 45 to 50.
Electroforming of nickel or the like is performed in an electroforming liquid at a temperature of ℃ to a predetermined thickness to form an electroformed film that is integrated with the conductive film to serve as a stamper, and is used as a master with a stamper. After that, the back surface of the electroformed film of the master with a stamper is mirror-polished in an environment at room temperature, and the electroformed film is peeled from the substrate to obtain the stamper.

[0005]

However, in the above-mentioned conventional technique, when a master with a stamper electroformed in an environment of a liquid temperature of 45 to 50 ° C. is handled at room temperature of 25 ° C., for example, the temperature difference is Since it is 20 to 25 ° C., FIG.
As shown in, the difference in coefficient of thermal expansion between the glass substrate 21 and the nickel electroformed film (stamper) 24 (9 to 10 × 10 ⁻⁶ / ° C. for glass, 15 × 10 ⁻⁶ / ° C. for nickel). ℃)
This causes a bimetal-like warp. In particular, the warp is remarkable when a master having a small area and a large area is used. In the polishing step after electroforming, if there is a warp, it becomes difficult to make the thickness uniform. Generally, since the master is glass, it takes a considerable amount of force to bend it, so there is a problem that it is difficult to correct the warp of the master with a warped stamper and polish it. There is a problem that the master will be broken if added. Further, in order to suppress the warp, it is possible to deal with it by making the glass of the master plate thicker, but there are problems such as poor workability and high cost.

The present invention has been made in view of the above problems, and an object thereof is to provide a method for manufacturing a stamper in which a warp amount of a master with a stamper can be reduced and a stamper having a uniform thickness can be easily obtained. To do.

[0007]

According to the stamper manufacturing method of the present invention, an electroforming step for performing electroforming and a polishing step for performing polishing are performed on a stamper master having an uneven pattern corresponding to information to be recorded. In the method for manufacturing a stamper that is provided, it is characterized in that the polishing step is performed in a temperature environment in which the amount of warpage of the stamper-equipped master is equal to or less than a certain value.

Further, the stamper manufacturing method of the present invention is
In a stamper manufacturing method having an electroforming step for performing electroforming and a polishing step for performing polishing on a stamper-containing master having a concavo-convex pattern corresponding to information to be recorded, the warp amount of the stamper-containing master is less than a certain amount. Therefore, the polishing step is performed while adjusting the environmental temperature.

[0009]

[Operation] In a temperature environment where the amount of warp is below a certain level, or by performing the polishing process while adjusting the environmental temperature so that the amount of warpage is below a certain amount, the warpage due to the difference in the coefficient of thermal expansion between the stamper and the master is caused. To make it easier to grind the stamper to a constant thickness.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. The stamper manufacturing method of this embodiment is shown in FIG.
As shown in, a glass master 3 (which is a master in which a resin film 10 having a concavo-convex pattern is formed at a predetermined depth with a resist or a photosensitive resin (replica resin) on the surface of a substrate 11 such as glass which has been polished with good flatness. After forming a conductive film 7 of nickel or the like on FIG. 1 (a) (FIG. 1 (b)), electroforming of nickel or the like is performed to a predetermined thickness to integrate the conductive film 7 with a stamper. The electroformed film 4 is formed. After that, while adjusting the environmental temperature so that the warp amount of the stamper-equipped master becomes less than a certain value, the back surface of the electroformed film 4, which is the upper surface in the drawing, is mirror-polished to obtain a stamper-equipped master (electroformed film-coated master) 1 ( In FIG. 1C, the electroformed film 4 of the master 1 with a stamper is peeled off from the glass master 3 to obtain a metal stamper.

FIG. 2 is a schematic view showing an example of the method for adjusting the environmental temperature used in this embodiment. Master 1 with stamper consisting of electroformed film 4, resin film 10 and substrate 11
Is attached to a polishing device 2 housed in a heating mechanism 5 composed of a known constant temperature bath. By this heating mechanism 5, the stamper master 1 and the polishing device 2 are brought into a temperature environment in which the warp is reduced to a certain level or less, and then the surface polishing is performed.

The environmental temperature during polishing in the present invention may be any temperature as long as the temperature is such that the warp is below a certain level. The amount of warp varies depending on the area, shape (circle, square, etc.) of stamper master 1, thickness of master and stamper (electroformed film), so adjust the environmental temperature of the master with stamper to keep the warp below a certain amount. Then, the master 1 with a stamper and the polishing device 2 are placed under that temperature environment for polishing. A preferable temperature environment is almost the same as the liquid temperature during electroforming, that is, the liquid temperature ± 20.
Within ℃, preferably within ± 10 ℃, more preferably ± 5
Within the range of ℃. The warp amount is reduced to a maximum value of 100 μm or less, more preferably 50 μm or less. When the electroformed film 4 is thinned by polishing, the amount of warp also changes and becomes smaller. Therefore, it is also possible to freely control the amount of warp by changing the environmental temperature.

As a method for adjusting the ambient temperature, there is a method in which the polishing apparatus 2 is placed in the heating mechanism 5 shown in FIG. 2 to polish the ambient temperature higher than room temperature, or the temperature is raised higher than room temperature. The polishing device 2 is put into the prepared liquid, and the master 1 with a stamper is polished therein, the polishing dish of the polishing device 2 is heated to a certain temperature, and the polishing is freely performed. You can choose to.

As long as the material of the substrate 11 constituting the glass master 3 is a material capable of flat polishing with good flatness and parallelism,
Any material can be used. For example, materials such as glass, ceramics, metals, and metal compounds are preferable. The thickness of the substrate 11 can be freely selected within a proper range such as weight and price. 1 depending on the shape and area of the substrate 11.
A range of up to 30 mm is preferred. If the area of the substrate 11 is small, the warp will be small, but the size and number of patterns to be put in one sheet will be small or small, and if the area is large, the mechanical strength of the substrate 11 will be weak and the board 11 will warp under its own weight. I will end up. Round-shaped right angle, square-shaped diagonal length of 10 to 10
A range of 2000 mm is preferred.

As a method for forming a concavo-convex pattern such as a track groove on the substrate 11, a method of applying a photoresist to a uniform thickness and then performing exposure and a phenomenon, or a master in which a concavo-convex pattern is formed beforehand and an ultraviolet curable resin are used. Can be freely selected from the method of transferring and forming the concavo-convex pattern with, or the method of applying a photoresist, performing the same exposure and phenomenon, and then performing dry or wet etching.

The material of the electroformed film 4 (that is, stamper) to be electroformed on the glass master 3 can be freely selected from metals such as gold, chromium and nickel or alloys and compounds thereof.
Further, a multi-layer structure in which a layer of another material is inserted in the surface layer or in the middle may be used. The preferred material is nickel or its alloys. The thickness of the electroformed film 4 can be freely selected according to the strength required for the molding method (injection molding, press molding, extrusion molding, ultraviolet ray or electron beam curing resin molding) used when forming the electroformed film 4. it can. Preferred thickness is 10-10
It is in the range of 00 μm. The temperature of the electroforming liquid (plating liquid) during electroforming varies depending on the type of the liquid used, but it is 10
The range of -100 ° C is preferred. Especially when using a nickel sulfamate plating solution, the range of 40 to 60 ° C. is preferable. The electroforming conditions can be freely selected within an appropriate range depending on the plating solution used. As an appropriate range, for example, the film itself of the electroformed film 4 does not have much stress, and the stress value of the film measured by a spiral stress meter manufactured by Yamamoto Plating Tester is in the range of -3 to 3 kg / mm ² . Is preferred.

Hereinafter, the present invention will be described more specifically by showing experimental examples, but the present invention is not limited thereto. Experimental Example 1 Photoresist (AZ1300, Hoechst Japan) on a glass plate (Asahi Glass) having a thickness of 10 mm and a diameter of 355 mm.
Is applied to a thickness of 0.11 μm, the pattern is exposed and developed with a laser exposure machine (Matsushita Electric), and the pitch is 1.6 μm.
A concavo-convex concavo-convex pattern having a width of m, a width of 0.7 μm, and a depth of 1100 Å was formed. After that, nickel was stapped to a thickness of 1000 Å to make it conductive. The glass plate on which this uneven pattern is formed has an outer diameter of 400 mm and an angle of 45 mm.
And fixed to a master holder in which a taper having a length of 10 mm was formed. The anode used was one in which a nickel ball was placed in a titanium basket and covered with a cotton cloth to prevent dust from flowing away. As the electroforming liquid, a liquid mixed with the following composition was put in an electroforming tank of 150 liters and a preliminary tank of 350 liters, and the whole liquid was circulated at a cycle of 10 times / hour at a liquid temperature of 45 ° C. .

Nickel sulfamate (tetrahydrate) 45
0 g / liter boric acid 30 g / liter pit inhibitor 5 ml / liter Current condition is 0.1 A / dm ² for 30 minutes, then 5
The current was increased to A / dm ² and electroforming was performed until the integrated current value for 13000 A was reached to obtain an electroformed film having a thickness of 300 μm. A glass master with an electroformed film, that is, a master with a stamper, was placed on a flat surface at room temperature (20 ° C.) and the warpage was measured. The glass surface (the surface on which the electroformed film was not formed) was convex. Up to 90μ in a bowl shape
It was warped (dial gauge, Mitutoyo). The thickness of the electroformed film is 300 ± 5 μm in the central part and 350 ± 5 in the outer peripheral part.
μm (micrometer, Mitutoyo). This warped master with stamper was heated in warm water to measure the change in the amount of warp while raising the temperature. 70μm at 30 ℃, 4 at 40 ℃
It was 0 μm, 30 μm at 45 ° C., and 20 μm at 50 ° C. Therefore, in a polishing liquid in which alumina at 50 ° C was mixed with water,
The stamper master and the polishing dish were all immersed, and the entire surface was polished to a mirror surface with a uniform thickness. The thickness of the electroformed film was 290 ± 3 μm on the entire surface, which was sufficiently uniform.

Experimental Example 2 A glass plate (Asahi Glass) having a thickness of 10 mm and 340 × 300 mm and having the same size with a pitch of 12 μm and a width of 3.0.
An ultraviolet curable resin (Asahi Kasei Kogyo, A.P.R.) having a thickness of 50 μm was sandwiched between a photomask (HOYA) having an uneven pattern of μm and a depth of 3000 Å and cured. After curing, the photomask was removed to obtain a glass master. Nickel is sputtered onto this glass master by 1000
Å Attached to form a conductive film. This glass master has an outer shape of 500 m
It was installed in a master holder in which a taper with an angle of 45 degrees and a length of 10 mm was formed. The same electroforming apparatus as in Experimental Example 1,
Using an electroforming liquid, electroforming was performed at 10,000 A for the same liquid temperature and the same current density as in Experimental Example 1 to obtain a stamper master having a 200 μm electroformed film. When the warpage was measured at room temperature (20 ° C.) in the same manner as in Experimental Example 1, the bowl shape was warped up to 120 μm in the direction in which the glass surface was convex. When the master with a stamper is put in a heating mechanism of 45 ° C, which is the same as the temperature of the electroforming liquid, and the warp is measured in an environment of 45 ° C, the maximum is 3
It was 5 μm. The thickness of electroformed film is 230 ± 5μ in the center
m and 290 ± 10 μm at the outer peripheral portion. A polishing apparatus was placed in a heating mechanism at 45 ° C., and polishing was performed in this environment in the same manner as in Experimental Example 1. The thickness of the electroformed film is 230 ± on the entire surface.
It was 3 μm and was sufficiently uniform.

Experimental Example 3 The same electroforming was carried out in the same manner as in Experimental Example 1, except that the same glass master disk, the same electroforming apparatus, the same master holder, the same electroforming solution, the same liquid temperature, and the same current density were used. When the warpage was measured in the same manner as in Experimental Example 1, the bowl shape was warped at a maximum of 115 μm in the direction in which the glass surface was convex. Put the master with stamper in the heating mechanism of 45 ° C which is the same as the temperature of the electroforming liquid,
When the warp was measured in an environment of 45 ° C., the maximum was 35 μm. The thickness of the electroformed film was 230 ± 5 μm in the central portion and 290 ± 10 μm in the outer peripheral portion. Polishing was carried out in the same manner as in Experimental Example 1 in a polishing liquid at 45 ° C.

When the outer peripheral portion was polished to 30 μm, the warp of the stamper-equipped master was reduced to a maximum of 15 μm, so the temperature of the polishing liquid was lowered to 35 ° C. When the outer peripheral portion was further polished to 230 μm, which is the same as the central portion, the amount of warp of the master became 10 μm again. Therefore, the temperature of the polishing liquid was lowered to 25 ° C., which is the same as room temperature, and polishing was continued. The thickness of the electroformed film after polishing was 200 ± 3 μm over the entire surface, which was sufficiently uniform.

Comparative Example 1 The same electroforming as in Experimental Example 1 was performed in the same manner with the same master, the same electroforming apparatus, the same holder of the same master, the same electroforming liquid, the same liquid temperature, and the same current density. When the warpage was measured in the same manner as in Experimental Example 1, the bowl shape was warped at a maximum of 115 μm in the direction in which the glass surface was convex. Same as the temperature of electroforming liquid 4
Put the master with stamper into the heating mechanism of 5 ℃, 45 ℃
When the warp was measured under the environment, the maximum was 35 μm. The thickness of the electroformed film is 230 ± 5 μm in the central part and 290 in the outer peripheral part.
It was ± 10 μm. When the back surface of the electroformed film was polished at room temperature, the film thickness after polishing was 170 μm at the center,
It was not possible to make the thickness of the electroformed film uniform with the outer peripheral portion of 230 μm.

[0023]

According to the present invention, the stamper master is polished in a temperature environment in which the warp amount is not more than a certain value, whereby the warp amount of the stamper master is reduced to easily obtain a stamper having a uniform thickness. There is an effect that is. Further, there is an effect that the use range of the liquid temperature during electroforming can be widened.

[Brief description of drawings]

FIG. 1 is a schematic process drawing showing an embodiment of a stamper manufacturing method of the present invention.

FIG. 2 is a schematic diagram showing an example of a means for adjusting the environmental temperature used in this example.

FIG. 3 is an explanatory diagram showing a conventional technique.

[Explanation of symbols]

1 Master with stamper 2 Polishing equipment 3 glass master 4 Electroformed film 5 Heating mechanism 7 Conductive film 10 Resin film 11 board

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hirofumi Kamikohara             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Kai Hill             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Osamu Kaname             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Naoki Kushida             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation

Claims (2)

[Claims] 1. A method of manufacturing a stamper, comprising: an electroforming step for performing electroforming and a polishing step for performing polishing on a stamper-based master having an uneven pattern corresponding to information to be recorded. A method for manufacturing a stamper, which comprises performing the polishing step in a temperature environment in which the amount is not more than a certain value. 2. A stamper manufacturing method, comprising: an electroforming step of electroforming and a polishing step of polishing a stamper master having an uneven pattern corresponding to information to be recorded, wherein the stamper master is warped. A method for manufacturing a stamper, which comprises performing the polishing step while adjusting the environmental temperature so that the amount becomes equal to or less than a certain value.