JPH07161079A - Fixing method of stamper - Google Patents

Abstract

PURPOSE:To form a 2P substrate excellent in mechanical characteristics by applying an active ray-setting resin compsn. on the signal face side of a stamper and irradiating with actinic rays to cure the resin compsn. to form a protective film. CONSTITUTION:A stamper 1 is mounted on a rotating table and rotated at a low speed, on which an actinic ray-setting type resin compsn. 2 is applied with a dispenser. Then a flat plate 3 is mounted to spread the actinic ray-setting resin compsn. In this process, an adhesive 5 is applied in a ring shape of proper radius on a stamper table 4 with using a dispenser while the stamper 1 is mounted on the rotating table and rotated. Thus, the adhesive 5 can be uniformly spread between the stamper 1 and the stamper table 4. By curing the adhesive 5, the stamper 1 is adhered and fixed to the stamper table 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical disk substrate having a concavo-convex pattern such as guide grooves and / or signal pits, and more specifically, a method for fixing a stamper by adhering the stamper to a stamper table. Regarding

[0002]

2. Description of the Related Art Optical discs are roughly classified into three types: a read-only type, a write-once type, and a rewritable type. The read-only type and the write-once type optical discs are already used in various fields. The development of rewritable optical discs is also progressing rapidly, and in particular, magneto-optical discs are about to be put into practical use.

On the optical disk substrate, a guide groove for guiding a laser beam and / or a concavo-convex pattern such as preformatted signal pits are generally formed in advance. This optical disk substrate is a thermoplastic resin such as polymethylmethacrylate or polycarbonate, a thermosetting resin such as epoxy resin, a radiation-polymerizable resin composition such as urethane acrylate, or a polyolefin characterized by low birefringence and low water absorption. It is manufactured by transferring a stamper on which a desired concavo-convex pattern is formed by a known means such as an injection molding method or a 2P method using a material such as a system resin.

Here, a method of manufacturing the stamper will be briefly described. First, a stamper master is manufactured. As the master material, glass is generally used, which is a material that is relatively easy to process with a high degree of surface accuracy and is chemically stable. The glass is processed into a disk shape, the surface is polished, and then washed. The glass is coated with a photoresist, baked, and then exposed to laser light modulated by the output of the signal generator. By developing the exposed photoresist layer, a glass master having a desired uneven pattern is completed.

Next, by means such as electroless plating or vapor deposition on the surface of the glass master disk on which the concavo-convex pattern is formed,
Conducting treatment is performed by forming a metal thin film such as nickel or silver. Subsequently, nickel is plated by electroforming to a desired plate thickness (usually about 300 μm). The nickel plate formed in this manner is a die for molding an optical disk substrate called a stamper.

After the electroforming step, the stamper is peeled off from the glass master, the inner diameter and the outer diameter are machined by a lathe or a punching device, etc. according to the application thereafter, and the back surface is polished if necessary. In the final stage, cleaning is performed to remove the residual photoresist or to remove the adhering foreign matter.

The stamper manufactured in this manner has a guide groove for guiding the laser beam and / or a concavo-convex pattern of micron order such as preformatted signal pits. If a defect occurs due to the contact between the two and non-removable foreign matter is attached, an error may occur in the final product optical disc. Therefore, it is necessary to protect the concavo-convex pattern by forming a protective film on the surface of the stamper when processing the inner and outer diameters of the stamper, carrying it, or adhering it to a stamper fixing jig such as a 2P molding machine. Usually, for this purpose, for example, a solution containing a vinyl chloride resin as a main component is applied by a method such as a spin coating method, a dipping method or a spray method to form a protective film on the stamper surface. In particular, in the step of adhering to a stamper fixing jig such as a 2P molding machine, in order to maintain the flatness of the stamper, it is required that the protective film thickness be uniform and that the film thickness be controlled. However, it is very difficult to form a uniform protective film having a constant thickness by the dipping method or the spray method, and it is not suitable for this purpose.

In that respect, the spin coating method can relatively easily form a uniform coating film having a desired film thickness by controlling the coating amount of the protective material and the rotation speed of the object to be coated. Are suitable for this purpose, and the spin coating method is often used.

Here, the spin coating method will be briefly described. The spin coating method is a method of forming a coating film by applying an appropriate amount of a liquid coating material on an object to be coated and scattering the excess coating material by centrifugal force generated by rotating the object to be coated. . When forming a coating film on a disk-shaped object such as an optical disk or a stamper, a dedicated device called a spin coater is usually used. The spin coater is equipped with a dispenser capable of controlling the coating amount and coating position of the liquid coating material with high precision, and a turntable capable of freely controlling the rotation speed of the coating object. By controlling these spin coating conditions with high precision, it is possible to easily form a uniform coating film having a desired film thickness as described above.

[0010]

By the way, when a protective film is formed on the surface of the stamper by the spin coating method, the stamper is rotated at a high speed (hundreds to thousands of rpm), so that the stamper is securely mounted on the turntable of the spin coater. Need to be fixed to. As this means, conventionally, a suitable jig is manufactured to press the inner peripheral portion of the stamper, a suction port is provided in the turntable to vacuum-adsorb the back surface of the stamper, a turntable is manufactured using a magnet, and a stamper made of nickel is used. There is a method of adsorbing by magnetic force.

However, whichever of the above-mentioned methods is used, when the stamper is attached to or detached from the turntable, an unreasonable force is applied to the stamper made of a nickel plate having a thickness of several hundreds of μm, resulting in mechanical deformation. It causes damage such as. When a substrate is molded using a stamper that has undergone mechanical deformation in this way, it adversely affects the mechanical properties of the molded substrate, particularly the properties that are important as optical disc substrates such as warpage angle and instantaneous surface wobbling acceleration. is there.

The problem to be solved by the present invention is that the stamper can be fixed to the stamper table for a 2P molding machine while the stamper signal surface is protected without damaging the stamper such as mechanical deformation. Excellent 2
An object of the present invention is to provide a method of fixing a stamper that can mold a P substrate.

[0013]

In order to solve the above-mentioned problems, the present invention (1) applies an actinic ray-curable resin composition to the signal surface side of a stamper, and is capable of transmitting actinic rays and excellent in flatness. Step of spreading the resin composition by using a plate, and then irradiating an actinic ray to cure the resin composition to form a protective film, (2) the side opposite to the signal surface side of the stamper And a stamper table are bonded together with an adhesive, and (3) a third step of peeling the protective film from the signal surface of the stamper is provided.

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

1 and 2 are schematic cross-sectional views showing a step of protecting the signal forming surface of the stamper by the first step of the stamper fixing method of the present invention. Reference numeral 1 denotes a laser beam formed by electroforming. A stamper having guide grooves and / or information signals such as preformat signal pits formed therein, 2 is an actinic ray curable resin composition that is cured by irradiation with actinic rays such as ultraviolet rays and electron beams, 3 is glass, etc. The plate is transparent to the actinic rays of. After applying the actinic ray curable resin composition 2 on the signal surface of the stamper 1,
The flat plate 3 is placed and the actinic ray curable resin composition is spread. At this time, install the stamper 1 on the rotary table,
By applying the actinic ray curable resin composition 2 in a ring shape at an appropriate radial position of the stamper 1 using a dispenser while rotating at a low speed, the actinic ray curable resin composition 2 of the stamper 1 and the flat plate 3 is applied. Can be spread evenly between. As shown in FIG. 2, after spreading the actinic ray curable resin composition 2, the actinic ray curable resin composition 2 is cured by irradiating the actinic ray through the flat plate 3. Thereby, the signal surface of the stamper 1 can be protected.

FIG. 3 is a schematic cross-sectional view showing a step of adhering the stamper to the stamper table by the second step of the stamper fixing method of the present invention. Reference numeral 4 is a stamper table, and the stamper 1 is a 2P molding machine. It is a jig used for mounting on. The stamper table requires high dimensional accuracy and is made by processing metal such as stainless steel. 5 is a stamper 1 and a stamper table 4
It is an adhesive for bonding. The adhesive 5 has an initial fluidity that spreads uniformly between the stamper 1 and the stamper table 4, and does not cause a peeling phenomenon between the stamper 1 and the stamper table 4 even after mass production of 2P molding after curing. It must have some degree of adhesion. The required adhesive strength depends on the stamper used and the 2P resin.
Also in this step, the stamper table 4 is placed on the rotary table, and the adhesive 5 is applied in a ring shape at an appropriate radial position of the stamper table 4 by using a dispenser while rotating at a low speed. Can be evenly spread between the stamper 1 and the stamper table 4. When the adhesive 5 is cured, the step of adhering the stamper 1 to the stamper table 4 is completed.

As shown in FIG. 4, when the stamper table 4 to which the stamper 1 is fixed is mounted on the 2P molding machine, the cured layer of the actinic ray curable resin composition 2 is simultaneously removed from the stamper 1 at the same time as the flat plate 3. Peel off.

[0018]

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

(Example) First, a nickel stamper manufactured by an electroforming method was used, and an outer diameter of 130 mm and an inner diameter of 36 m were used.
m and plate thickness 295 μm. This stamper was placed on a rotary table, and a UV curable resin "435-X" (manufactured by Dainippon Ink and Chemicals, Inc.) was applied in a ring shape on the signal surface of the stamper under the following conditions using a dispenser.

[435-X coating conditions] Resin temperature 25 ° C. Resin coating position Circumference of stamper radius 46 mm Nozzle Teflon needle φ0.4 mm Coating pressure 2.1 kg / cm ² Coating amount 1.5 g

On the "435-X" coated on the signal surface, a glass plate having an outer diameter of 140 mm, an inner diameter of 36 mm and a plate thickness of 2 mm was placed, and "435-X" was spread. "4
35-X ”spreads over the entire surface of the stamper, irradiates ultraviolet rays through the glass plate under the following conditions, and 435-X
Was cured to form a protective film.

[435-X curing conditions] Metal halide lamp 120 W / cm Ultraviolet irradiation amount 1000 mJ / cm ²

Next, the obtained stamper whose signal surface is protected by the protective film is fixed to the stamper table. The stamper table is a part of a 2P molding machine (manufactured by Dainippon Ink and Chemicals, Inc.) and is a jig for mounting the stamper on the 2P molding machine. The stamper table has an outer diameter of 1
It has a smooth surface of 32 mm and an inner diameter of 36 mm, and a stamper is bonded to this surface.

The adhesive for fixing the stamper to the stamper table is a two-component adhesive "T" manufactured by ThreeBond.
B2023B "and" TB2015C "in a weight ratio of 2:
The mixture of 1 was used.

A stamper table was placed on a rotary table, and the adhesive was applied in a ring shape on the stamper table.

[Adhesive coating conditions] Adhesive temperature 25 ° C. Nozzle Teflon needle φ0.6 mm Coating pressure 2 kg / cm ² Coating amount 400 mg

After the adhesive was applied on the stamper table, the surface of the stamper whose signal surface was protected and opposite to the signal surface was immediately placed on the adhesive application surface of the stamper table. Then, by leaving it to stand for 16 hours, the fixing of the stamper to the stamper table was completed.

After peeling off the protective layer consisting of the glass plate and "435-X" from the stamper, the stamper table was mounted on a 2P molding machine (manufactured by Dainippon Ink and Chemicals Co., Ltd.) and placed on a glass substrate having a diameter of 130 mm. UV curable resin "STM-401" (2P manufactured by Dainippon Ink and Chemicals, Inc.
A resin 2) was used to mold a glass 2P substrate.

With respect to the glass 2P substrate thus obtained, as the measured values of the mechanical characteristics, the values of the instantaneous surface wobbling acceleration and the warp angle, which tend to be out of the standard, were measured by an optical disk mechanical characteristic measuring device (manufactured by Shin Denshi Kogyo Co., Ltd.). And measure
evaluated. As a result, the instantaneous surface wobbling acceleration is 1.6 m /
The second ² and the sled angle were 0.3 mrad (millimeter radian).

(Comparative Example) A stamper having the same specifications as in the example was set on a rotary table made of a magnet, and an appropriate amount of Clincoat S (commercial stamper protective film forming material) was applied using a dispenser, and the rotation speed was changed. And, by controlling the rotation time, the surplus protective film forming material was scattered by centrifugal force to form a protective film. The stamper having the protective film formed thereon was adhered to the stamper table under the same conditions as in the example.

After the protective film was peeled off from the stamper, the stamper table was mounted on a 2P molding machine (manufactured by Dainippon Ink and Chemicals, Inc.), and then the diameter 13
A glass 2P substrate was molded using a 0 mm glass substrate. As a result of measuring the mechanical characteristics of the glass 2P substrate thus obtained in the same manner as in the example, the instantaneous surface wobbling acceleration is
The slew angle was 19.6 m / sec ² and 7.3 mrad.

[0032]

[Table 1]

[0033]

According to the tamper fixing method of the present invention,
It is possible to fix the stamper to the stamper table for a 2P molding machine while protecting the stamper signal surface without damaging the stamper by mechanical deformation or the like, and it is possible to mold a 2P substrate having excellent mechanical properties.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a step of forming a protective film on the signal surface side of a stamper.

FIG. 2 is a schematic cross-sectional view showing a step of forming a protective film on the signal surface side of a stamper.

FIG. 3 is a schematic cross-sectional view showing a step of adhering a stamper to a stamper table.

FIG. 4 is a schematic cross-sectional view showing a step of peeling the protective film from the signal surface of the stamper after adhering the stamper to the stamper table.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stamper 2 Actinic ray curable resin composition 3 Flat plate transparent to actinic rays 4 Stamper table 5 Adhesive

Claims (1)

[Claims] (1) An actinic ray-curable resin composition is applied to the signal surface side of a stamper, and the resin composition is spread by using a plate that is permeable to actinic rays and has excellent flatness. A first step of irradiating an actinic ray to cure the resin composition to form a protective film, (2) bonding the surface of the stamper opposite to the signal surface side and the stamper table with an adhesive. A method of fixing a stamper, comprising a second step and (3) a third step of peeling the protective film from the signal surface of the stamper.