JPH06168482A - Production of stamper master disk for optical recording medium - Google Patents

Abstract

PURPOSE:To produce the stamper original disk for an optical recording medium with a simple process by obviating the intrusion of bubbles into a resin, the bleeding out of the resin and the deflection of a cell. CONSTITUTION:This process for production of the stamper original disk for the optical recording medium has the process for using the cell 4 joined with a glass substrate 2 and an original mold 1 via a spacer 3, injecting a curing resin from an injection port 5 while the pressures in and out of the cell is held under the same reduced pressure state and curing this resin. The cell has two pieces of the injection port 5 and discharge port 8 which are through-holes.

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 a stamper master for an optical recording medium. The master produced by the method of the present invention has a concave-convex pattern for optical recording on the surface, and is used for producing an optical recording medium stamper by laminating and peeling a metal thin film and a metal layer thereon. To be done.

[0002]

2. Description of the Related Art Conventionally, as a general method for manufacturing a stamper master for an optical recording medium, a photocurable resin (hereinafter referred to as 2P) is used on at least one of an original mold and a replica substrate.
(Hereinafter referred to as resin) is applied or dropped (hereinafter referred to as dispense), and then the original mold and the substrate for replica are superposed to spread the photocurable resin (hereinafter referred to as spread), and at least one of them is spread in that state. The 2P resin was cured by further irradiating light, and then the original mold and the replica substrate were peeled off, and a photocurable resin replica was transferred and manufactured on the substrate.

6 (a) to 6 (c) illustrate the steps of this conventional method. First, the original mold 1 is fixed to the fixing plate 11, and a predetermined amount of 2P resin 9 is dispensed on the original mold 1 [FIG. 4 (a)]. Then, the glass substrate 2 is overlaid, the 2P resin 9 is spread over the entire surface between the original mold 1 and the glass substrate 2, and ultraviolet light (UV light) is irradiated from the glass substrate 2 to cure the 2P resin 9 [FIG.
(B)]. After that, the cured 2P resin 10 is peeled off from the original mold 1 together with the glass substrate 2 to cure 2P.
P resin 10 (2P replica) was manufactured [Fig. 4
(C)].

[0004]

However, in such a conventional method, air bubbles are mixed in the resin at the time of stacking or spread, or the excess 2P resin is dispensed to prevent the 2P resin from squeezing out. There were problems such as occurrence. For the protrusion, see FIG.
As shown in (c), 2P is applied to the end of the cured 2P resin 10.
The resin protrusion 10 'may be formed. If this projection 10 'is left as it is, a chip will be generated in a later step and it will become dust and adhere to the pattern part of the 2P replica, or adhere to the end part of the original mold,
There is a problem that when it is used again for manufacturing a 2P replica, the projection becomes an original type projection. Therefore,
Applying a release agent to the edges of the original mold and the glass substrate, or using a masking agent, it hardened to form burrs. 2
It is conceivable to peel off the P resin. However, the removed burrs may adhere to the 2P replica or the pattern surface of the original mold and cause defects, which is also undesirable.

As a conventional technique for solving these problems,
As described in JP-A-61-213130, there is a method of preventing the protrusion by spreading in a vacuum to prevent air bubbles from entering and further providing a leak preventing wall of 2P resin on the outer peripheral edge portion. However, when such a prevention wall is provided, it is difficult to accurately control the supply amount of the 2P resin to be dispensed, and when the supply amount is insufficient, the 2P resin may not be supplied to the uneven pattern portion. Further, in the case of an excessive amount, protrusion occurs beyond the prevention wall.

In addition to the above problems, this conventional method also cures 2P resin at the peripheral edge of the prevention wall due to curing shrinkage of the 2P resin.
There is also a problem that the resin peels from the original mold, so-called "float" or "sink" occurs. As a conventional technique for solving such a problem, there is a method, as described in JP-A-1-196748, for reducing floating and sinking by interposing an elastic body made of rubber or spring between the original mold and the substrate. is there. In addition to that, in order to eliminate the protrusion and bubbles of the photocurable resin, after forming the cell in advance,
It has also been proposed that the photocurable resin is injected from the injection port of the cell by applying a pressure difference between the photocurable resin and the suction. However, in these methods, it is necessary to treat the sealing material in addition to the spacer in order to hermetically seal the cell, and to press and fix the cell, which complicates the treatment process. Further, since the cell is pressed and fixed or a differential pressure is applied to the photocurable resin, there is a risk that the center portion of the cell bends and the flatness of the 2P replica deteriorates.

The present invention has been made to solve the above-mentioned various problems of the prior art. That is, an object of the present invention is to provide a method capable of producing a stamper master for an optical recording medium by a simple process without inclusion of bubbles in the resin, extrusion of the resin, and deflection of the cell.

[0008]

The above object of the present invention is to form an internal space for resin molding by joining a substrate and an original die having a concavo-convex pattern through a spacer located at an outer peripheral portion. A cell having a curable resin injection port and a curable resin discharge port for communicating the internal space with the outside is used, and the curable resin is injected under the same reduced pressure in the internal space of the cell and the external pressure. This is achieved by a method of manufacturing a stamper master for an optical recording medium, which has a step of injecting a curable resin into the internal space from an inlet and a step of curing the curable resin injected into the internal space of the cell.

[0009]

In the present invention, the resin is injected into the cell while keeping the pressure inside and outside the cell at the same reduced pressure, so that the cell does not bend due to the pressure difference. In addition, the inside of the cell is not a closed space but communicates with the outside through an inlet and an outlet, so that the sealing properties (sealability) of the components such as spacers.
Since it does not have to be perfect, it can be carried out by using a simple member, and there is no problem of sealing failure in the conventional method. Furthermore, since a cell having an inlet and an outlet is used, residual air bubbles do not occur in the cell even if the vacuum degree of the chamber is low. Specifically, good injection is possible even in a low vacuum of about 1 Torr, which is advantageous in terms of equipment. The method of the present invention is an extremely excellent manufacturing method as a whole due to the synergistic effect of each of these constitutions and functions.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1A is a diagram illustrating a cell used in the method of the present invention, and FIG. 1B is a sectional view taken along the line AA '. The cell 4 shown in FIG. 1 is formed by installing a spacer 3 having a predetermined thickness on the outer peripheral edge between the original mold 1 and the glass substrate 2, and joining the two to face each other via the spacer 3. Through holes are provided at two positions of the glass substrate 2 at desired positions near the outer periphery of the cell 4 outside the effective pattern area, which are used as a resin inlet 5 and a resin outlet 8. This through hole can be provided in the original mold 1 as long as it is outside the effective area. Also, original type 1
Is the surface having the concave-convex pattern 1 ′ such as a pit groove as the inner side, while the inner surface of the glass substrate 2 is a flat surface.

Next, as shown in FIG. 2, the cell 4 is installed in the chamber 6. Inside the chamber 6, a funnel 12 in which uncured 2P resin is stored, a solenoid valve 13 for opening and closing the bottom of the funnel 12, and a funnel 14 located further below the funnel 12.
A tube 15 communicating with this is provided, and an exhaust port 7 for exhausting the inside of the chamber 6 is also provided. Here, the injection port 5 of the cell 4 is connected to the tube 15. Then, the air in the chamber 6 is exhausted from the exhaust port 7 to be in a reduced pressure state (vacuum state).

Next, as shown in FIG. 3, the solenoid valve 13 is opened while the chamber 6 is kept in a constant depressurized state, so that the 2P resin 9 in the funnel 12 and the funnel 14 and the tube 15 in the lower portion are opened. Then, it is introduced into the cell 4 through the injection port 5.
This 2P resin 9 is poured into the cell 4 until it reaches the same height as the 2P resin 9 accumulated in the funnel 14, and an extra 2
The P resin is discharged from the discharge port 8.

Next, as shown in FIGS. 4 (a) to 4 (d), UV light is irradiated from one surface of the cell 4 in which the resin injection is completed [FIG. 4 (a)]. As a result, the 2P resin in the cell 4 is cured [FIG. 4 (b)]. Next, the original mold 1 and the substrate 2 are separated and separated, and the spacer 3 is also separated [FIG. 4 (c)]. In this way, a stamper master for an optical recording medium having the 2P replica 10 on the glass substrate 2 is obtained [FIG. 4 (d)].

The spacer 3 may have a function of making the thickness (so-called gap) of the cell 4 constant and a sealing function of preventing the 2P resin inside the cell 4 from leaking to the outside. The thickness of the spacer 3 (the thickness of the space inside the cell 4) is preferably 5 to 500 μm, and further 10 to 3
00 μm is preferable, and 20 to 100 μm is particularly preferable. If this thickness is less than 10 μm, it is necessary to maintain the flatness of the original mold 1 and the substrate 2 with extremely high accuracy. Further, if this thickness exceeds 500 μm, the amount of 2P resin used becomes unnecessarily large and is likely to be wasted.

The first method for producing the cell 4 is first.
In this method, a gap material having a predetermined outer diameter is mixed into the sealing material as required, and the sealing material is dispensed on the outer peripheral edge portion of the original mold 1 or the glass substrate 2 by a predetermined amount to form a superposed body. There is a method of solidifying the sealing material to form the spacer 3. As a result, the cell 4 having a space having a predetermined thickness can be obtained. The gap material to be mixed into the sealing material as needed is, for example, particles having a desired outer diameter, and specifically, inorganic or organic fine particles such as alumina beads, zirconia beads, polystyrene beads, and microballoons are used. It is possible. It is also possible to use whiskers having a predetermined diameter. Various materials having a sealing function can be used as the sealing material, and are not particularly limited. However, when the gap material is used in combination, it is preferable to use an optical or thermosetting resin from the viewpoint of dispersibility of the gap material and ease of dispensing. Examples of this curable resin include acrylic resins,
Examples include silicone-based, polyester-based, epoxy-based, and urethane-based resins.

As a second method for producing the cell 4, there is a method of using a sealing material that simultaneously satisfies the gap control function and the sealing function. This second method can be achieved by using a film material as the sealing material. As the film material, a metal thin film such as an aluminum foil or a plastic film can be used. In particular, considering the adhesiveness between the original mold 1 and the glass substrate 2, it is preferable to use a plastic film. As the plastic film, for example, a film of polyethylene, polypropylene, polyvinyl alcohol, polyethylene terephthalate, polyacetyl cellulose, polyamide, polyimide or the like can be used. By properly selecting the thickness of the plastic film, the gap amount inside the cell 4 can be regulated and the sealing property can be secured.

As shown in FIGS. 4C and 4D, the spacer 3 is finally removed and the cured 2P resin 10 (2P replica) is formed on the glass substrate 2. Here, if a film material is used as the spacer 3, there is also an advantage that the removal thereof is simple. In particular, in the present invention,
As described above, since there is no difference in the pressure inside and outside the cell 4 (inside the chamber 6), almost no pressure is applied to the constituent members of the cell 4 and the cell 4 does not bend. Therefore, a material having a sealing function as the spacer 3 (double-sided adhesive sheet material or the like) can also be used.

FIG. 5 is a diagram showing a mode in which cells are formed by using a sheet with double-sided adhesive on the spacer 3 and 2P resin is injected in the present invention. In this mode, since the 2P resin is injected while the cell 4 is not placed upright and is placed horizontally, it is not necessary to harden or clamp with a sealing material, and it is possible to form a cell wax only by the adhesiveness of the adhesive tape. It is possible to significantly reduce the process.

The stamper master obtained by the method of the present invention described above is used for the purpose of manufacturing a stamper for an optical recording medium. For example, a metal thin film of Ni, Cr or the like is formed on the 2P replica 10 of the master by a sputtering method or the like. Next, a thicker metal is laminated on this metal thin film by electroforming, and the metal layer formed by electroforming is separated from the 2P replica together with the thin film layer formed by the sputtering method or the like to obtain a metal stamper. . Usually, this is used as a stamper for molding plastics by subjecting it to a desired shape by polishing the surface or reinforcing the backing.

Hereinafter, the present invention will be described in more detail with reference to more specific examples.

<Embodiment 1> First, the pattern area is 25
A 300 × 300 mm square original mold, which is 0 × 250 mm, was prepared. Next, a photo-curable resin (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: Hard Rock OP4515) was added to microspheres having an average particle diameter of 40 μm (manufactured by Nippon Ferrite Co., Ltd.,
5% by weight of trade name EXPANCEL DU) was dispersed, and the dispersion was dispensed on the outer periphery of the original mold by a dispenser. Next, a glass substrate having an inlet and an outlet of 340 × 340 mm as shown in FIG. 1 was superposed, and the photocurable resin was irradiated with ultraviolet rays to be cured to form a spacer 3, thereby obtaining a cell 4. The effective area of this cell was approximately 270 x 270 mm.

The cell thus manufactured was placed in the vacuum chamber 6 as shown in FIG. In particular,
First, the injection port 5 of the cell 4 was connected to the lower funnel 14 with a fluororesin tube 15 and arranged. Next, the upper funnel 12 that can be opened and closed from the outside of the chamber by the solenoid valve 13 is arranged so that 2P resin (product name INC118, manufactured by Nippon Kayaku Co., Ltd.) can be dropped into the funnel 14. The resin was collected. Next, the air in the chamber 6 was exhausted from the exhaust port 7, the internal pressure was adjusted to 0.1 Torr, and the vacuum degree was maintained for 30 minutes to defoam the 2P resin. Subsequently, the solenoid valve 13 was opened and 2P resin was dropped into the funnel 14 to start the resin injection into the cell. At this time, the viscosity of the 2P resin is 7
It was 70 cp, and the injection was completed in about 8 hours. During this injection, if the cell was heated as necessary to reduce the viscosity of the 2P resin, the time required for the injection was further shortened.

Next, the cell 4 in which the 2P resin was injected was taken out from the chamber 6, the tube 15 was removed from the cell 4, and the 2P resin was cured by irradiating ultraviolet rays from the glass substrate side. Then, when the original mold and the glass substrate were peeled off, a 2P replica in which the uneven pattern of the original mold was faithfully transferred was obtained without bubbles. Also, this 2P
The flatness of the replica was molded to 10 μm or less over the entire surface, and the flatness of the original mold was maintained. Of course, there was no burr caused by the protrusion of 2P resin.

<Example 2> 100 μm as a spacer
A cell was prepared in the same manner as in Example 1 except that a thick polyethylene film with a double-sided adhesive material was attached. After uniformly pressing and fixing this cell with a jig from above and below, Example 1
2 was carried out in the same manner as in Example 1 except that the chamber was placed in a vacuum chamber and the chamber pressure was set to 1 Torr.
2P resin was injected into the cell by the self-weight pressure of P resin.

According to this embodiment, it was possible to easily install the spacer material without the need to dispense or cure the spacer material. Also, since the spacer material is tape-shaped, it is easy to remove after curing the 2P resin,
There was no sink mark or peeling due to 2P resin shrinkage.

[0027]

As described above, according to the method of the present invention, a stamper master for an optical recording medium can be manufactured by a simple process without inclusion of bubbles in the resin, protrusion of the resin, and cell deflection. .

Further, according to the present invention, as a stamper for an optical recording medium, it is possible to obtain a stamper master plate for an optical recording medium, which can efficiently manufacture various stampers having an outer shape other than a circular shape, for example, a rectangular stamper.

[Brief description of drawings]

FIG. 1A is a diagram illustrating a cell used in the method of the present invention, and FIG. 1B is a sectional view taken along the line AA ′.

FIG. 2 In one embodiment of the method of the present invention, 2P in a cell.
It is a schematic diagram which illustrates the state before injecting resin.

FIG. 3 In one embodiment of the method of the present invention, 2P in a cell.
It is a schematic diagram which illustrates the state after injecting resin.

4 (a) to (d) are schematic views illustrating a step of UV-curing the 2P resin in the cell to remove the mold, in one embodiment of the method of the present invention.

FIG. 5: In another embodiment of the method of the present invention, 2 in a cell.
It is a schematic diagram which illustrates the state after injecting P resin.

FIG. 6 is a schematic view illustrating the steps of a conventional method.

[Explanation of symbols]

 1 Original type 1'Concavo-convex pattern 2 Glass substrate 3 Spacer 4 Cell 5 Injection port 6 Chamber 7 Exhaust port 8 Discharge port 9 Unhardened 2P resin 10 Hardened 2P resin 10 'Protrusion 11 Fixed plate 12 Funnel 13 Solenoid valve 14 Funnel 15 Tube

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Kamitakahara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kai-oka 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Osamu Kaname 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Naoki Kushida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Within

Claims (1)

[Claims] 1. An internal space for resin molding is formed by joining a substrate and an original die having a concavo-convex pattern through a spacer located at an outer peripheral portion, and the internal space communicates with the outside. A cell having a curable resin injection port and a curable resin discharge port is used, and the curable resin is injected into the internal space from the curable resin injection port under the same reduced pressure of the internal space and the external pressure of the cell. And the process of
And a step of curing the curable resin injected into the inner space of the cell.