JP2612622B2 - Roll type stamper, method of manufacturing the same and forming roll - Google Patents

Description

The present invention relates to a high-density information recording medium such as an optical disk for recording / reproducing information by changing optical characteristics such as reflectivity by light such as a laser beam. The present invention relates to a stamper used for forming unevenness of a preformat signal and unevenness of a guide groove for a tracking signal on the substrate.

[Conventional technology]

Conventionally, the injection molding or compression molding is performed in the production of the above-mentioned medium substrate, but in these production methods, the flatness, smoothness, warpage, mixing of bubbles, and the like of the substrate are liable to occur. Since it significantly impairs, it is very difficult to determine conditions of temperature and pressure, precision of a mold, prevention of generation of air bubbles, and the like, and the apparatus is large and the cost is vague. Further, in the compression molding, since the single-wafer processing is used, the post-process is complicated and productivity is poor. In injection molding, like an optical card,
It is not possible to manufacture a thin storage medium with a substrate thickness of 0.4 mm.

On the other hand, in the case of a flat plate formed by extrusion molding of plastic, a smooth and uniform plate without air bubbles can be easily manufactured. Therefore, a method has been proposed in which a stamper is closely attached to the flat plate to apply pressure to transfer unevenness. When pressure is applied to
Requires very high pressure.

As a method of solving this, if the plastic sheet in the molten state extruded from the extruder is passed between the forming roll with the stamper in close contact and the mirror roll, the unevenness of the stamper can be cut into a flat plate with a small pressure. Then, if the center hole and the outer periphery are trimmed, a medium substrate can be easily obtained with a small device. Also, it can be easily manufactured even with a thin substrate such as 0.4 mm.

Further, according to this manufacturing method, a substrate forming step, a recording layer forming step, a protective substrate bonding step, and the like can be performed in a continuous step, and a step with excellent productivity can be realized.

As a forming roll, there is a roll obtained by attaching a Ni stamper to a mirror roll. Conventionally, a stamper used for the forming roll is manufactured by uniformly applying a resist on a glass master, forming predetermined irregularities by a laser, forming a Ni conductive film on the surface by sputtering, and then forming an electrode. Ni by casting method
The metal film is formed and peeled off from the glass master.

[Problems to be solved by the invention]

However, the stamper manufactured as described above must be wound around a roll in order to make it adhere to the roll. At that time, there is a problem that the stamper is distorted and good transfer cannot be obtained. In the case of an optical disk, the pitch of the unevenness is 1.6 μm, and even a slight distortion of the stamper poses a serious problem.

The glass master is inflexible and it is difficult to bend to the curvature of the roll, but if you leave the strain in the stamper at the time of electroforming, when it is peeled off from the glass master due to the strain,
Since the stamper warps with a certain curvature, it is possible to make a stamper having a predetermined curvature. However, a distorted stamper has a problem that it changes with time.

Further, in order to bend the stamper in accordance with the curvature of the roll, it is necessary to reduce the thickness of the stamper. However, when the stamper is thin, the stiffness of the stamper is weakened, the stamper is distorted when bent, and the backside polishing of the stamper becomes difficult. If the back surface of the stamper has irregularities, it is transferred to the substrate, and a good substrate cannot be obtained. For this reason, the thickness of the stamper is required to be 300 μm or more, but the diameter of the roll used for extrusion molding is usually about 300 mm and the curvature of the roll is large, so that it is very difficult to wind the stamper around this roll.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances of the related art, and provides a roll-type stamper capable of producing a forming roll having no distortion and a novel method of producing the same.

[Means for solving the problem]

The present invention is a roll-type stamper comprising a conductive film having a desired uneven shape and an electroformed layer, which is attached to a forming roll used for manufacturing an optical recording medium substrate by extrusion forming, wherein the electroformed layer has A curvature that can be attached to and integrated with a forming roll, which is formed by electroforming the conductive film fixed in an electroforming apparatus so as to have the same curvature as a forming roll. A roll having a roll-type stamper, and a method of manufacturing the same, and a forming roll having the roll-type stamper attached thereto. According to the present invention, when a conductive film is subjected to electroforming, the film is already formed with a forming roll. Since it is fixed at the same curvature, no distortion occurs in the electroformed layer formed and it is stable over time, and the forming roll obtained by attaching the obtained roll die stamper to the forming roll is extruded by the extrusion method. It can be produced with good productivity substrates for good optical recording medium if placed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a roll type stamper for integrating a stamper onto a mirror roll for molding without applying a load to the stamper, that is, without bending the stamper. A stamper may be formed by deforming the conductive film at a predetermined curvature from the step of forming the desired unevenness or the step of forming the master, but in the present invention, the following is preferred. That is, the conductive film is usually formed on a master having desired irregularities formed by sputtering or the like, and the surface to be sputtered for uniform sputtering has the same plane and the same crystal growth direction. In the present invention, processing is preferably performed on a flat surface similarly to a known technique until the formation of a conductive film, and after the forming,
Before providing the electroformed layer, the conductive film is deformed and fixed at a predetermined curvature.

Here, the deformation at a predetermined curvature means that the surface is fixed so as to have the same curvature as the forming roll, and the surface of the mirror-like roll that matches the surface of the mirror-like roll constituting the forming roll with the stamper is used. This is to fix the conductive film at the same curvature as the curvature.

In order to deform the conductive film at a predetermined curvature after forming the conductive film, the conductive film may be formed using a flexible master.

There are roughly two ways to form a conductive film.
One is to etch the resist on a flexible substrate to form the desired protrusions, coat an oxide film on this, and then form a conductive film. The other is to apply the resist on a glass master in advance. The desired convex portion of the metal formed by using
2P (photoresist) provided on a flexible substrate
This is a method of forming a conductive film after transferring to a resin and forming irregularities. In both cases, the conductive film is provided on a flexible master having a desired uneven shape on the conductive film. Here, the flexible master is basically a flexible substrate and a layer having an uneven portion formed on the substrate, and can be considered to have substantially the same physical properties as a flexible substrate. is there. In the present invention, not limited to these methods, any method can be applied as long as desired unevenness can be formed using a conductive film.

In the present invention, the desired irregularities are irregularities of a preformat signal provided on a substrate of an optical recording medium, irregularities of a guide groove for a tracking signal, and the like.

A flexible substrate is a substrate that can be easily deformed at a predetermined curvature and fixed to a jig or the like. The deformation causes the substrate to be unevenly deformed, broken, or adversely affects the conductive film. Not something. Since the diameter of the mirror roll for forming is usually 300 mm, it is stable at a predetermined thickness and deformed with such a curvature. Specifically, a thin plate of metal, ceramics, etc. can be used,
For example, if a thin plate made of alumina or the like is bent to a curvature of 300 mmφ, it may be broken, and handling is troublesome and not suitable. The flexible substrate needs to be a conductor to be mounted on an electroforming jig and to perform electroforming of the conductive film. When a layer for forming desired irregularities on the conductive film is formed not by transfer but by direct etching of a resist on a flexible substrate, it is preferable that the surface roughness of the flexible substrate can be reduced. .

In addition, as an electroforming jig for mounting a flexible master that can be used in the present invention at a predetermined curvature, usually,
A jig used in the electroforming process may have a predetermined curvature, and may be a jig to which a flexible master is mounted.

When the thickness of the electroformed layer is 100 μm or less, the strength is weak and distortion tends to occur when the electroformed layer is attached to a roll. On the other hand, if the thickness is too large, the electroforming takes too much time and the electroforming itself is distorted. Therefore, the thickness is preferably 500 μm or less.

〔Example〕

 Hereinafter, the present invention will be described in detail based on examples.

Example 1 FIG. 3 is a schematic diagram showing a configuration in which a forming roll is formed using a roll-type stamper manufactured according to the present invention, and desired irregularities are transferred to a plastic flat plate. Is a thermoplastic synthetic sheet such as polycarbonate, 3 is a forming roll, 4 and 5 are mirror-finished pressure rolls,
6 is a take-up machine. The distance between the rolls 3 and 4 and the rolls 3 and 5 can be adjusted so that the irregularities of the forming roll 3 can be sufficiently transferred to the surface of the sheet 2. Then, the sheet 2 extruded from the extruder 1 is inserted into rolls 3 and 4 and rolls 3 and 5 in a softened state, and the irregularities of the forming roll 3 and the mirror surfaces of the mirror rolls 3 and 4 are applied to the sheet 2. The images are sequentially transferred and moved in the direction of the arrow in the figure to complete the transfer.

FIG. 1 is a schematic view of a manufacturing process of a forming roll stamper according to the present invention, which is performed in the order of (a) → (f).

In the step (a), a resist 8 is applied on the flexible substrate 7. As the flexible substrate, for example, a Ni sheet having a thickness of 0.3 mm, a surface of the sheet polished, and a surface roughness of 0.5 μm is used.

On this Ni sheet, for example, resist AZ1300-46cp
(Hoechst Japan), resist: thinner = 1:
The substance diluted at a weight ratio of 2 is applied with a spinner.

Next, in step (b), tracking is performed by cutting and developing a predetermined concavo-convex pattern (concentric, spiral, stripe) using an exposure apparatus such as a laser cutting machine and a contact exposure apparatus PLA (Canon). A master 9 is obtained by forming a fine pattern of concaves and convexes such as grooves for information and information bits.

Further, in the step (c), a conductive treatment is performed on the master 9 and electroforming is performed to form a predetermined shape of the stamper. However, if the metal is electroformed on the metal, it becomes difficult to separate the master 9 and the stamper later. Therefore, first, an oxide film 10 such as SiO _{2 is} sputtered on the master 9 by several tens of nm, and then the conductive material such as Ni is made conductive. About membrane 11
Conduction treatment is performed by sputtering 100 nm.

The master 9 manufactured in this manner is set on an electroforming jig 12 that matches the curvature of the roll of the extruder (step (d)). Next, the electroforming jig 12 is attached to the electroforming apparatus 13 to perform electroforming to form an electroformed layer on the conductive film 11 (step (c)). Ni is generally used for the electroformed layer, and as the electroforming solution 14 for electroforming Ni, a nickel sulfamate electroforming solution was used.

An example of the liquid composition of the nickel sulfamate electroforming solution 14 used here is as follows.

Surufarumi, nickel tetrahydrate _{[Ni (NH 2 SO 3)} 2 · 4H
₂ O] 500 g / boric acid [H ₃ BO ₃ ] 37 g / pit preventive agent 2.8 ml / The conductive film 11 is used as a negative electrode, the nickel chip 16 is used as a positive electrode, and the motor 15 rotates at 20 to 30 rpm. Then, while rotating the master 9 on which the conductive film is formed, it is made to conduct in the nickel sulfamate electroforming solution 14 to deposit nickel on the master 9 on which the conductive film is formed to form a stamper.

34AH (ampere-hour)
Thus, a stamper having a thickness of 200 μm is formed.

Next, the back surface of the stamper thus formed is polished. Since the stamper is thin, it is better to perform the back surface polishing with the electroforming jig attached. Grinding while adjusting to the curvature of the roll causes less distortion. If the back surface has a rough surface, the roughness is transferred during the molding of the substrate, so that it is necessary to polish it to 1 μm or less. If the stamper is mirror-finished and the stamper is peeled off from the master, an R (roll) stamper having the same curvature as a predetermined roll can be obtained (step (f)).

Next, this R-type stamper is attached to a roll. In the case of an optical disk substrate, the substrate is 1.2 mm, and a roll diameter of 250 mm or more is required to form a sheet of this thickness. If the disk diameter is 5 inches, the size of the stamper is only 6 inches. Good. Apply a heat-resistant adhesive to the roll, attach an R-type stamper on it, cover the surface of the R-type stamper with a protective cover such as silicon so as not to damage it, and have the same curvature as the roll from above. A press is prepared, heated and pressed so as not to distort the stamper, and the roll and the R-shaped stamper are integrated to form a forming roll. As the heat-resistant adhesive used, for example, a silicon adhesive TSE322 (Toshiba Silicon) was used. When polycarbonate is used as the substrate material of the optical disc, the molding temperature by the roll is 150 ° C., so that a higher heat resistance is required.

This molding roll was attached to an apparatus as shown in FIG. 3, and polycarbonate was extruded. As a result, a good disc substrate having a constant uneven pitch was obtained stably.

Embodiment 2 FIG. 2 is a schematic view showing a manufacturing process of an R-type stamper according to another embodiment of the present invention, which is performed in the order of (A) → (E).

In the step (A), 300 nm of Cr is sputtered as a metal film 31 on a mirror-polished 30 cm square glass 10 mm thick,
Further, the resist thereon is the same as that shown in the first embodiment.

Next, in the step (B), using a laser cutting machine, an exposure apparatus such as a contact exposure apparatus PLA (Canon), and cutting and developing the pattern of the concavo-convex pattern of the striped optical card, the tracking groove and the information groove are formed. A fine pattern of irregularities such as pits is formed. The concavo-convex pattern at this time is a reverse pattern to the pattern attached to the substrate.

In the step (C), Cr is etched with an etching solution,
An uneven pattern of Cr is formed.

In the step (D), a photopolymer (2P) resin 34 is applied to a flexible substrate 33, and the glass master 30 of the step (C) is placed thereon, and the uneven pattern is transferred to the 2P resin.
Irradiate ultraviolet rays to cure the 2P resin.

As the flexible substrate, the thin metal plate used in Example 1 is used. However, the surface roughness need not be as mirror as in the first embodiment. This is because a 2P resin surface to which a mirror-polished glass surface is transferred is used. Since it is difficult to mirror-polish a thin metal plate, this method does not require much labor.

Next, in step (E), the 2P is subjected to a conductive treatment. The stamper peels off at the interface with 2P without forming an oxide film as in the first embodiment. The conductive treatment is performed by the same Ni sputtering as in the first embodiment.

This conductive original master was set on a curved electroformed jig in the same manner as in Example 1, electroformed, polished on the back side, and then removed from the jig to form an R-type stamper.
This is attached to a mirror roll to form a forming roll.

This forming roll was attached to the extruder shown in FIG. 1, and polycarbonate was extruded to form a sheet having a thickness of 0.4 mm. As a result, a good optical card substrate was obtained as in Example 1.

〔The invention's effect〕

As described above, when producing a stamper by electroforming,
An R-shaped stamper without distortion is manufactured by setting a flexible master with irregularities on a jig with the same curvature as the roll and casting it. By attaching this to a mirror roll, it can be formed without distortion. A roll is formed, and if this forming roll is used, a good substrate of the optical recording information medium can be obtained with good productivity by the extrusion method.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are process diagrams of manufacturing the forming roll stampers performed in Examples 1 and 2 of the present invention in the order of (a) → (f) and (a) → (e). The figure is a schematic view showing a process for manufacturing a substrate of an optical recording medium using the forming roll of the present invention. DESCRIPTION OF SYMBOLS 1 ... Extruder, 2 ... Thermoplastic synthetic sheet 3 ... Forming roll 4, 5 ... Mirror pressure roll 6 ... Take-off machine, 7 ... Flexible substrate 8 ... Resist, 9 ... Flexible Master disk 10: oxide film, 11: conductive film 12: electroforming jig, 13: electroforming device 14: electroforming liquid, 15: motor 16: nickel chip 17: electroforming layer , 30 ... Glass master 31 ... Metal film, 32 ... Resist 33 ... Flexible substrate 34 ... 2P resin

Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // B29L 17:00 (72) Inventor Hirofumi Uehara 3-3-2 Shimomaruko, Ota-ku, Tokyo Canon stocks In-company (72) Inventor Hitoshi Yoshino 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-56-86721 (JP, A) JP-A-62-217442 (JP, A)

Claims (9)

(57) [Claims] 1. A roll-type stamper comprising an electroconductive layer having a desired uneven shape and an electroformed layer, which is attached to a forming roll used for manufacturing an optical recording medium substrate by extrusion. Characterized by being formed by an electroforming process of the conductive film fixed in an electroforming apparatus so as to have the same curvature as a forming roll, wherein the curvature can be integrated with a forming roll. Roll type stamper having 2. A forming roll obtained by attaching the roll-type stamper according to claim 1 to a forming roll. 3. The roll-type stamper according to claim 1, wherein the electroformed layer is made of Ni having a thickness of 100 to 500 μm. 4. A method for producing a roll-type stamper to be attached to a molding roll used for producing an optical recording medium substrate by extrusion molding, by subjecting a conductive film having a desired uneven shape to electroforming. Characterized in that the electroforming process is performed by fixing the conductive film in an electroforming apparatus so as to have the same curvature as the forming roll, and has a curvature which can be integrated with the forming roll. A method of manufacturing a roll stamper. 5. The electroforming apparatus according to claim 5, wherein said conductive film is formed in a concave and convex shape on a flexible master, and is fixed in said electroforming apparatus by fixing said flexible master to an electroforming mold having the same curvature as a forming roll. The method according to claim 4, wherein the method is performed by attaching to a tool. 6. The method according to claim 5, wherein the flexible master is formed by providing a resist on a flexible substrate, etching the resist, forming a desired convex portion, and then coating an oxide film. . 7. The flexible master is obtained by applying a photopolymer (2P) resin on a flexible substrate and transferring the convex portion to the resin using a glass master having a convex portion made of a metal prepared separately. The method according to claim 5, which is obtained by forming a desired uneven shape. 8. The method according to claim 6, wherein the electroformed layer is Ni having a thickness of 100 to 500 μm. 9. The method according to claim 6, wherein the flexible substrate is a metal plate.