JPH05282712A - Production of master optical disk - Google Patents

Abstract

PURPOSE:To obtain the master optical disk which can be formed with coating films of a UV curing resin having a uniform film thickness and has rugged patterns of precise shapes. CONSTITUTION:A chucking table having the approximately uniform state of contact with a glass master disk in a region to be formed with rugged patterns is used at the time of imposing the glass master disk on the chucking table and spin coating the disk with the UV curing resin. Such chucking table is constituted by having an outer peripheral rib 6a and an inner peripheral rib 6b in the parts respectively exclusive of the regions to be formed with the rugged patterns and is so formed that the glass master disk is imposed thereon by these ribs 6a, 6b.

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 master, and more particularly to an improvement of a chucking table used to mount a glass master when spin-coating a glass master with an ultraviolet curable resin.

[0002]

2. Description of the Related Art In optical discs such as digital audio discs (so-called compact discs) and video discs, an optical disc master used for copying pits, grooves, etc. on a substrate is usually prepared by the following steps.

That is, a glass master having a polished surface is placed on a chucking table having a vacuum chucking function with the polished surface facing upward. Then, after the UV-curable resin is spin-coated on the polished surface of the glass master, the UV-curable resin is transported to a heat treatment device such as an electric furnace or a hot plate to dry the UV-curable resin. Next, a concave-convex pattern is recorded on this ultraviolet-curable resin coating film by a laser beam (so-called cutting process), and development is performed to manufacture an optical disc master.

Here, a chucking table on which a glass master is placed when spin-coating an ultraviolet curable resin has a structure as shown in FIGS.

That is, the chucking table 81
Has a disc-shaped chuck base 82. The chuck base 82 has a closed convex outer edge 83 at the outermost peripheral surface and a hollow shaft portion 84 at the center of the back surface.
Are formed so as to project. The hollow shaft portion 84 has a suction hole 92.
Is connected to a vacuum pump, and the atmosphere of the suction portion surrounded by the outer edge 83 is exhausted by the vacuum pump via the hollow shaft portion 84. In addition, a plurality of ribs 86 for mounting the glass master 91 are formed in the suction portion in concentric circles with different radii at regular intervals. Each of the concentric ribs 86 is provided with two rib cutouts 87 at two positions, whereby a vacuum path is formed, and the atmosphere of each groove 88 surrounded by the rib 86 passes through the cutout 87. And then exhausted. The chucking table 81 has a rotary drive system 90 and is rotatable by the rotary drive system 90.

When spin coating the ultraviolet curable resin, the glass master 91 is concentrically placed on the chuck base 82 of the chucking table 81 having such a structure, and the vacuum pump is operated. Then, the atmosphere of the suction part of the chucking table 81 is exhausted, and the glass master 91 is adsorbed and fixed to the chucking base 82. Then, while the glass master 91 is fixed on the chucking base 82 in this manner, spin coating of the ultraviolet curable resin is performed.

[0007]

However, when the ribs of the chucking table and the glass master disk are in contact with each other during spin coating, heat generated by a rotary drive system such as a motor is passed through the ribs to the glass master disk. As a result, the amount of heat is supplied to the ultraviolet curable resin with high efficiency only in the portion corresponding to the rib contact portion. In that case, the drying speed differs between the portion corresponding to the rib of the ultraviolet curable resin and the portion not corresponding to the rib, and the ultraviolet curable resin coating film having a uniform film thickness cannot be formed. For example, when trying to form a UV-curable resin coating film with a film thickness of 1000Å, the film thickness difference is up to 3
It reaches 0Å.

The film thickness of the uneven pattern forming region of the ultraviolet curable resin coating film formed at this time directly influences the height dimension of the unevenness formed on the ultraviolet curable resin in the subsequent step. For this reason, as described above, when the chucking table is used in which the ribs abut over the entire area of the glass master, and the film thickness of the ultraviolet curable resin coating film becomes uneven over the entire area, the manufactured optical disk master The height of the unevenness also varies accordingly, which causes a problem that a good reproduction signal cannot be obtained in the finally manufactured optical disc.

Therefore, the present invention has been proposed in view of such a conventional situation, and it is possible to form an ultraviolet curable resin coating film having a uniform film thickness in an uneven pattern forming region.
An object of the present invention is to provide a method for manufacturing an optical master disc, which can manufacture a master optical disc having no unevenness in height.

[0010]

In order to achieve the above-mentioned object, a method for manufacturing an optical disk master according to the present invention comprises placing a glass master on a chucking table and spin-coating an ultraviolet curable resin on the chucking table. In the method of manufacturing an optical disc master that exposes and develops an ultraviolet curable resin to form a concave-convex pattern in accordance with an information signal, the contact state of the chucking table with the glass master is substantially uniform in the concave-convex pattern formation region. It is what

Here, the contact state being substantially uniform means that the ribs are not in contact at all in the concavo-convex pattern forming area or the chucking table is in uniform contact with the concavo-convex pattern forming area. is there. Further, the chucking table has an outer peripheral rib and an inner peripheral rib, and the glass master is supported by these ribs.

[0012]

In order to manufacture the optical disk master, the glass master is first placed on the chucking table, and the glass master is spin-coated with the ultraviolet curable resin.

At this time, if the contact state of the chucking table with the glass master is not uniform in the concavo-convex pattern forming region, the heat generated by the motor or the like serving as a rotary drive system is transferred non-uniformly to the ultraviolet curable resin. Thereby, the ultraviolet curable resin coating film, in the uneven pattern forming region,
Only a certain portion is dried rapidly, and a uniform film thickness is not formed.

On the other hand, if the contact state of the chucking table with the glass master is substantially uniform in the concave / convex pattern forming area, the ultraviolet curable resin coating film does not rapidly dry only a certain portion in the concave / convex pattern forming area. , With a uniform film thickness.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a method of manufacturing an optical disk master according to the present invention will be described below with reference to the drawings.

To manufacture an optical disk, first, an optical disk master for transferring the concavo-convex pattern to the stamper is manufactured.

In order to manufacture an optical disk master, first, the surface of the glass master to which the ultraviolet curable resin is applied is polished, and then the glass master is cleaned in an extremely clean environment in order to remove dust and dirt adhering to the surface. Wash and dry with.

Then, the thus-polished and cleaned glass master is placed on a chucking table having a vacuum chucking function so that the polished surface faces upward, and spin coating, heat treatment, and optical coating of an ultraviolet curable resin. An uneven pattern is formed by cutting and development is performed.

Here, in order to form a concavo-convex pattern having a uniform height dimension on the ultraviolet curable resin coating film, the ultraviolet curable resin coating film having no film thickness variation is formed at least in the concavo-convex pattern forming region by spin coating. I need to leave.

Therefore, in the present invention, a chucking table on which the glass master is placed is one in which the contact state with the glass master is substantially uniform in the concavo-convex pattern forming region. By using a chucking table in which the contact state with the glass master is substantially uniform in the concave / convex pattern forming area, the ultraviolet curable resin coating film does not dry rapidly only in a part of the concave / convex pattern forming area. Therefore, it is formed with a uniform film thickness.

The chucking table is specifically constructed as shown in FIGS. 1 and 2. That is, the chucking table 10 has the chuck base 1 molded in a disc shape. The chuck base 1 has an outer edge 2 which is closed at the outermost peripheral portion of the surface, and a recess surrounded by the outer edge 2 serves as a suction portion 3 which sucks and adsorbs the glass master. On the other hand, a hollow shaft portion 4 is formed so as to project at the center of the back surface of the chucking base 1. The hollow shaft portion 4 is connected to a vacuum pump (not shown), and the atmosphere of the suction portion 3 is exhausted by the vacuum pump through the hollow shaft portion 4. Also, this suction unit 3
Includes an inner peripheral rib 6a and an outer periphery 6b which serve as a glass master mounting portion.
However, a plurality of concentric circles are formed at regular intervals with different radii only in the portion of the glass master disk except the concavo-convex forming area 5a. Each of the concentric ribs 6a, 6b is provided with a rib cutout 7 at two locations, so that a vacuum path is formed and the atmosphere in each groove surrounded by the ribs passes through the cutout 7. It is designed to be exhausted. It should be noted that such a chucking table 10 has a rotary drive system 11 and is rotatable by the rotary drive system 11.

When spin coating the ultraviolet curable resin, the glass master 5 is placed concentrically on the chuck base 1 of the chucking table 10 having such a structure,
Operate the vacuum pump. Then, the atmosphere of the suction unit 3 of the chucking table 10 is exhausted, and the glass master 5 is adsorbed and fixed to the chucking base 1.

Then, with the glass master 5 fixed on the chucking table 10, an ultraviolet curable resin is spin-coated on the glass master 5. In order to spin coat the ultraviolet curable resin, the ultraviolet curable resin is supplied to the central portion of the glass master 5 and the chucking table 10 is rotated at a predetermined rotation speed, and the supplied ultraviolet curable resin is spread over the entire surface of the glass master. Let

At this time, the thickness distribution of the formed ultraviolet-curable resin coating film (Sample 1) in the radial direction is determined by a conventional chucking table (a chucking having a rib for mounting the glass master on the concavo-convex forming region). Table 1 and FIG. 3 show a comparison with an ultraviolet curable resin coating film (Comparative Sample 1) formed by using a table.

[0025]

[Table 1]

From Table 1 and FIG. 3, when the chucking table without ribs is used in the concavo-convex forming region, the ultraviolet curable resin coating film having a uniform film thickness is formed as compared with the case where the conventional chucking table is used. It can be seen that

In the above chucking table, the glass master mounting portion of the chuck base is provided in a region other than the concavo-convex pattern forming region so that the chuck base does not contact the concavo-convex forming region of the glass master. However, as the chucking table, the chuck base may be made of a porous material, and the glass base mounting surface of the chuck base may be flat. Also in this case, only the portion where the ultraviolet curable resin coating film is present is not rapidly dried, and a uniform film thickness is formed.

After the UV-curable resin coating film is formed in this manner, the glass master is conveyed to a heat treatment apparatus such as a hot plate or an electric furnace for heat treatment to dry and stabilize the UV-curable resin coating film.

Then, after forming the uneven pattern by a technique such as optical cutting, the uneven pattern is exposed by exposing to a developing solution. At this time, if the concentration of the developing solution is lowered intermittently or continuously in accordance with the progress of development, the development can be reliably stopped during the development stop process, and irregularities having a precise shape can be formed.

That is, at the time of development, it is necessary to surely stop the development when the development reaches the end point level while observing the progress of the development. For example, when the development is carried out beyond the end point level of the development, the ultraviolet curable resin is excessively etched and the precision of the uneven shape is lowered.

However, when a developing solution having a constant concentration is used for the development, the developing always proceeds at a high speed when the developing solution has a high concentration, and the developing continues even after the development stop processing. It takes a long time to stop, resulting in overdevelopment. At this time, if the developing speed is lowered by lowering the concentration of the developing solution or performing the developing in a low temperature environment, the stopping treatment can stop the developing at almost the end point level. Roughness occurs and causes noise.

On the other hand, in the developing process, if the concentration of the supplied developer is lowered intermittently or continuously according to the progress of the development, the development can be carried out at a high speed by the developer of high concentration when the unevenness is revealed. In the vicinity of the end point level of the development, the low-concentration developing solution causes the development to proceed at a low speed, so that the stop processing can surely stop the development.

It is possible to reduce the concentration of the developer according to the progress of development by using a development control system as shown in FIG. 4, for example.

That is, in the development control system, the ratio I ₁ / I ₀ between the incident light quantity I ₀ and the first-order diffracted light quantity I ₁ when the laser light is perpendicularly incident on the film surface of the glass master is used as an index of the progress of the development. And the incident light quantity I ₀ and the first-order diffracted light I of the first developer tank 31 for storing the high-concentration developer and the second developer tank 32 for storing the low-concentration developer. A detection unit 33 that detects ₁ is included.

The first developer tank 31 and the second developer tank 32 are provided with pipes 33 and 34 which flow out when the developer is pressurized with N ₂ , and these tanks 31 and 32 are attached. One ends of the pipes 33 and 34 attached to the three-way valve 35 are attached to the valves 36 and 37 of the three-way valve 35. The other valve 38 of this three-way valve has a nozzle 3 at one end.
The other end of the pipe 40 having 9 is attached, and the high-concentration developing solution and the low-concentration developing solution are jetted from the nozzle 39 to the glass master 5 by opening / closing the valves 36, 37, 38. ing.

Meanwhile, the detector 33, the I ₀ detector 41 for detecting the amount of incident light I ₀ consisting of I ₁ detector 42 for detecting a first order diffraction light quantity I _1. The I ₀ detector 41 and the I ₁ detector 42 are connected to a development control computer 43, and the information of the incident light amount I ₀ and the first-order diffracted light amount I ₁ detected by the detectors 41 and 42 is input to the development control computer 43. It is supposed to be done. The development control computer 43 is connected to the three-way valve 35, and I ₁ is calculated from the input incident light quantity I ₀ and first-order diffracted light quantity I _1.
/ I ₀ is calculated, and the opening / closing of the three-way valve 35 is controlled according to the value of I ₁ / I ₀ .

That is, the valve 36 on the first developer tank side is opened at the start of development, and the valve 3 on the second developer tank side is opened.
7 is closed. As a result, the high-concentration developing solution is ejected from the nozzle 39, and the development proceeds at a high speed. Then, when the development level is close to the end point and I ₁ / I ₀ reaches a predetermined value, the valve 36 on the first developer tank side is closed and the valve 37 on the second developer tank side is closed this time. Be released.
In response to this, the low-concentration developing solution is ejected from the nozzle 39, and the developing speed decreases. When the development further progresses and I ₁ / I ₀ reaches the end point level, both valves 3
6, 37 are closed. As a result, the supply of the developing solution from the nozzle 39 is stopped, and the stop water supply nozzle 4
Stopping water is supplied from No. 4 and development is completely stopped.

FIG. 5 shows a development time course when the development control system is used. In the figure, the horizontal axis represents the development time and the vertical axis represents I ₁ / I ₀ . In addition, as a comparison, FIG. 5 also shows a case where only a high-concentration developing solution is used throughout development and a case where only a low-concentration developing solution is used throughout development.

As can be seen from FIG. 5, when the above development control system is used, the development proceeds at a high speed at the start of the development, and the developing speed is reached when the supply developer is switched from the high concentration developer to the low concentration developer. Therefore, the development time can be shortened, and the development can be surely stopped when the development reaches the end point level.

On the other hand, when only the high-concentration developing solution is used, the development proceeds at high speed from the start of development to the end of development. Then, even after the stop processing, the development continues and it takes time to stop the development, resulting in overdevelopment. On the other hand, when only low concentration developer is used,
The development speed is slow throughout development, and it takes a considerable time to reach the development end point.

In the above development control system, it is preferable to use a low concentration developer having a concentration of 80% or more and less than 100% of the high concentration developer. The low-concentration developing solution in the above concentration range has an etching rate of 1/2 to 1/3 that of the high-concentration developing solution, and with such an etching rate, the development can be surely stopped at the end point of the development.

Further, the above-exemplified system intermittently lowers the concentration of the developing solution supplied to the glass master according to the progress of the development, but the developing solution supplied by using the mass flow controller. The concentration of may be continuously decreased.

In this case, as shown in FIG. 6, a developing solution storage tank 31 for storing a high-concentration developing solution, a pipe 45 having one end attached to the developing solution storage tank 31, and one end attached to a water supply source. A pipe 46 and a collecting pipe 47 connected to the other ends of these pipes are used. The collecting pipe has a nozzle 48 at the end opposite to the connecting portion to which the pipes are connected. Each of the nozzles passes through the pipe, and the high-concentration developer and water combined at the connecting portion pass through the collecting pipe to form the nozzle. Eject more. Further, the both pipes are provided with mass flow controllers 49 and 50, which control the flow rate by air valves, respectively in the middle, and the flow rates are controlled by the mass flow controllers 49 and 50. Then, by this, the amount ratio of the high-concentration developing solution and water that are combined at the connecting portion is adjusted, and the developing solution having a desired concentration is ejected from the nozzle.

In order to supply the developing solution to the glass master 5 by the above system, the high concentration developing solution should be 1
The flow rate of the high-concentration developer and the water flowing through the pipe so that the amount ratio of the high-concentration developer gradually decreases and the amount ratio of water increases as the development progresses. May be adjusted by the mass flow controllers 49 and 50. As a result, the concentration of the developer supplied to the glass master 5 continuously changes from a high concentration to a low concentration.

After the optical disk master is manufactured in this manner, the surface of the ultraviolet curable resin film is made into a conductor by an electroless plating method or a vacuum deposition technique. Next, the surface made conductive is used as a cathode, and nickel is placed as an anode, and electroplating is performed by energizing in a nickel sulfamate bath liquid to deposit metallic nickel to be a stamper on the glass master.
When this metallic nickel has a thickness of about 0.3 mm, electroforming is stopped, the stamper is peeled off from the glass master, and cleaning and drying are performed.

Then, the stamper thus manufactured is processed into a required shape, and the uneven pattern is transferred onto the substrate by using this stamper. The transfer method may be any of a compression method, an injection method, an injection compression method, a photopolymer method (so-called 2P method), and the like. Also,
There is no particular limitation on the material of the substrate, and acrylic resin,
Any commonly used substrate material such as polycarbonate resin may be used.

Further, the disc substrate on which the concavo-convex pattern is transferred is made into an optical disc by forming a reflection film or providing a protective layer, etc., but the optical disc may have any constitution, and therefore is formed on the disc substrate. The reflective film, recording film, protective film, etc. to be formed can be arbitrarily selected according to the application.

For example, a digital audio disc,
In a so-called CD-ROM or the like, a metal reflective film of Al or the like is formed on a disk substrate on which the concavo-convex pattern is transferred. In a magneto-optical disk, a perpendicular magnetization film having magneto-optical characteristics (Kerr effect and Faraday effect) is formed. In addition, it can be applied to an optical disc having a recording layer of a low melting point metal thin film, a phase change film, a film containing an organic dye, or the like. These reflective film and recording film can be formed by a vacuum thin film forming technique such as sputtering or vacuum deposition.

Further, the protective film formed on the recording film and the reflective film may be any ultraviolet protective resin layer or the like provided as a protective film in an ordinary optical disk. For example, in the case of an ultraviolet curable resin layer, it is formed by spin-coating an ultraviolet curable resin on the disk surface and photocuring it.

When the ultraviolet curable resin layer is formed,
Prior to that, when the disk surface is subjected to a coupling treatment with a coupling agent such as a silane coupling agent, the adhesiveness between the ultraviolet curable resin and the disk surface is secured, and the protective performance of the ultraviolet curable resin layer is further improved.

When the disc surface is subjected to the coupling treatment, if the mist-like or gaseous coupling agent is supplied to the protective film forming surface while rotating the disc, the coupling to the portion other than the protective film forming surface. The treatment can be performed without depositing the agent.

FIG. 7 shows a protective film forming system for sequentially performing the coupling process and the formation of the ultraviolet curable resin layer.

This protective film forming system has a coupling agent supply system 51 and an ultraviolet curing resin supply system 52, and the protective film formation surface of the disk 58 mounted on a chucking table 59 which is rotatable. Further, by supplying the coupling agent and the ultraviolet curable resin from the supply systems 51 and 52, respectively, the coupling treatment and the formation of the ultraviolet curable resin layer are sequentially performed.

That is, the above coupling agent supply system 51
Is composed of a coupling agent tank 54 for storing the coupling agent 53, an N ₂ gas introduction pipe 55 attached to the coupling agent tank 54, and a coupling agent supply pipe 56.

The N ₂ gas introducing pipe 55 has a tip 55a.
Is inserted into the coupling agent tank 54 and is attached to the coupling agent tank so that it is not immersed in the coupling agent 53. On the other hand, the coupling agent supply pipe 56 has a nozzle 57 at the tip, the nozzle 57 is located in the vicinity of the protective film formation surface of the disk 58, and the end 56a opposite to the nozzle side is inserted into the coupling agent tank 54. Coupling agent 53
It is attached to the coupling agent tank 54 so as not to be immersed in the. Further, the coupling agent supply pipe 56 is driven and operated so that the nozzle 57 moves along the radial direction of the disk 58.

In the coupling agent supply system 51, N ₂
When N ₂ gas is introduced into the gas introduction pipe 55, a gaseous coupling agent is generated in the coupling agent tank 54. The gaseous coupling agent passes through the coupling agent supply pipe 56 and is ejected from the nozzle 57.
At this time, by rotating the chucking table 59 and moving the nozzle 57 along the radial direction of the disk 58, the coupling agent adheres only to the protective film formation surface.

The above-mentioned coupling agent supply system supplies a gaseous coupling agent to the disc, but when supplying a mist-shaped coupling agent, as shown in FIG. N ₂ with bubbler 61 at the tip
Using the gas introducing pipe 60, the N ₂ gas introducing pipe 60 is attached to the coupling agent tank 54 so that the bubbler 61 is immersed in the coupling agent 53.

When N ₂ gas is introduced into the N ₂ gas introducing pipe 60, the coupling agent is bubbled by the bubbler to generate a mist-like coupling agent. The mist-like coupling agent passes through the coupling agent supply pipe 56 and is ejected from the nozzle 57.

On the other hand, the ultraviolet curable resin supply system 52 includes a resin tank 62 for storing the ultraviolet curable resin and a resin supply pipe 63 attached to the ultraviolet curable resin tank 62.
Consists of. The resin supply pipe 63 has an end 63a on the side opposite to the side where it is attached to the resin tank located on the upper inner periphery of the protective film formation surface of the disk 58, and has a pump 64 in the middle thereof. is doing.

Therefore, by operating the pump 64, the ultraviolet curable resin in the resin tank 62 is supplied to the inner peripheral portion of the protective film formation surface of the disk 58 through the resin supply pipe 63. Then, the chucking table 59 is rotated to apply the ultraviolet curable resin along the inner circumference of the protective film formation surface, the supply of the ultraviolet curable resin is stopped, and the chucking table is rotated at a predetermined rotation speed. Thereby, the ultraviolet curable resin is uniformly applied over the entire surface on which the protective film is formed, and the ultraviolet curable resin is irradiated with ultraviolet rays by the ultraviolet irradiation lamp 65, whereby the ultraviolet curable resin layer is formed.

The optical disc manufactured in this way is
Since the optical disk master has irregularities of uniform height, pits and grooves are precisely formed, and good reproduction signal characteristics are exhibited.

[0062]

As is clear from the above description, in the method of manufacturing an optical disk master according to the present invention, when the optical disk master is manufactured, the spin coat of the ultraviolet curable resin is formed into a concavo-convex pattern when it is in contact with the glass master. Since it is mounted on a chucking table that is substantially uniform in the area, a uniform uneven shape can be formed on the optical disk master.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a configuration example of a chucking table used in a manufacturing method of the present invention.

FIG. 2 is a schematic vertical cross-sectional view showing a configuration example of a chucking table used in the manufacturing method of the present invention.

FIG. 3 is a film thickness distribution diagram showing a film thickness distribution in the radial direction of an ultraviolet curable resin coating film.

FIG. 4 is a schematic diagram showing a configuration example of a development control system.

FIG. 5 is a characteristic diagram showing a relationship between developing time and I ₁ / I ₀ .

FIG. 6 is a schematic view showing another example of a developer supply system applied to the development control system.

FIG. 7 is a schematic diagram showing a configuration example of a protective film forming system.

FIG. 8 is a schematic view showing another example of the coupling agent supply system applied to the protective film forming system.

FIG. 9 is a schematic vertical sectional view showing a configuration example of a conventional chucking table.

FIG. 10 is a schematic plan view showing a configuration example of a conventional chucking table.

[Explanation of symbols]

 1 ... Chucking base 3 ... Suction part 6a ... Inner peripheral rib 6b ... Outer peripheral rib

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyoko Tada 6-5-6 Kitashinagawa, Shinagawa-ku, Tokyo Inside Sony Magne Products Co., Ltd.

Claims (2)

[Claims] 1. A method of manufacturing an optical disc master, in which a glass master is placed on a chucking table and a UV curable resin is spin-coated, and then the UV curable resin is exposed and developed to form an uneven pattern according to an information signal. The method for producing an optical disk master according to the method, wherein the contact state of the chucking table with the glass master is substantially uniform in the concavo-convex pattern formation region. 2. The method of manufacturing an optical disk master according to claim 1, wherein the chucking table has an outer peripheral rib and an inner peripheral rib, and these ribs support the glass master.