JPH09288851A - Device for manufacturing optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for manufacturing an optical disk capable of manufacturing the optical disk with high signal recording accuracy by a simple equipment. SOLUTION: The device is provided with a laser beam source 151 emitting UV laser beam, modulation means 152, 153 modulating the intensity of the UV laser beam emitted from the laser beam source 151 and optical means 154, 155, 156 irradiating an optical disk substrate 1 with the UV laser beam from the modulation means 152, 153 for processing and forming signal pits on the rotating optical disk substrate 1. Further, the device is provided with a supplying nozzle 13 which is arranged near a processing region on the optical disk substrate 1 and flows gas from a rotation center side of the optical disk substrate 1 toward the processing region and a suction nozzle 14 which is arranged at a position facing to the supplying nozzle 13 with the processing region and sucks gas flowed from the supplying nozzle 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing an optical disk, and more particularly to an apparatus for processing and forming signal pits on an optical disk substrate.

[0002]

2. Description of the Related Art A read-only optical disc, a write-once optical disc, and a rewritable optical disc, which are disc-shaped media for reproducing or recording information by using light, include compact discs, phase change discs, and magneto-optical discs. . Such an optical disc is manufactured as follows, for example. First, the supplied glass substrate is processed and polished, and then washed and dried. Subsequently, after a photoresist to be a recording film is coated on the surface of the glass substrate to a film thickness of about 0.1 μm, the glass substrate is baked (heat treatment) in an oven or the like.

Then, a laser beam is applied to the photoresist by a cutting machine to expose the photoresist. Here, the laser light has, for example, a wavelength of 44.
A 1 nm He: Cd laser is used, and a photoresist is irradiated after being focused to a diffraction limit spot size by an objective lens which is a condenser lens. Then, the photoresist is developed, the exposed portion of the photoresist is removed, and a groove serving as a tracking guide pattern and a signal pit serving as a recording signal groove are formed. further,
After the surface of the photoresist is made conductive, a nickel film is formed on the surface of the photoresist by electroless plating and electroforming. And this nickel film peels off
After cleaning, a nickel master having the same shape as the stamper described later is formed.

Next, after the surface of the nickel master is stripped (passivated), a second nickel film is formed again on the surface of the nickel master by electroless plating and electroforming. Then, the second nickel film is peeled off and washed to form a mother. Then, after the surface of this mother is stripped (passivation),
Further, a third nickel film is formed on the surface of the mother by electroless plating and electroforming. Then, the third nickel film is peeled off and washed to manufacture the stamper. Using the stamper thus formed, a resin disk is duplicated by injection molding a molten resin. And
A metal film is vacuum-deposited on the signal recording surface of the disc and coated with a resin as a protective layer to form a final optical disc.

[0005]

Since the glass substrate used in the conventional optical disk manufacturing apparatus is expensive, it is recycled and reused. However, dirt on the glass substrate adversely affects signal recording on the optical disk. Therefore, a high degree of cleanliness is required in the glass substrate recycling process. Further, since the glass substrate recycling process, the photoresist developing process, and the like are wet processes using a chemical solution, a plurality of large-scale devices capable of coping with these chemical processing processes are required. Therefore, a clean room having a high degree of cleanliness and a large space is required, and there is a problem that the equipment cost increases.

Further, in order to improve the accuracy of signal recording on the optical disk, it is necessary to minimize fluctuations and variations in the length of signal pits. However, since the signal pits are formed by a chemical development process, unless the quality control and process control such as the concentration of the developing solution and the development time are strictly performed, the length of the signal pits tends to be unstable, and There is a problem that there is a limit to reducing fluctuations and variations in pit length. Similarly, the film thickness of the photoresist also affects the signal recording accuracy of the optical disc, so the film thickness of the photoresist tends to become unstable unless quality control and process control of raw materials and film formation are strictly performed. However, there is a problem that there is a limit in reducing fluctuations and variations in the film thickness of the photoresist.

In view of the above points, an object of the present invention is to provide an optical disk manufacturing apparatus capable of manufacturing an optical disk having high signal recording accuracy with simple equipment.

[0008]

According to the present invention, the above object is to provide a laser light source for emitting an ultraviolet laser beam, a modulating means for modulating the intensity of the ultraviolet laser beam from the laser light source, and a rotating optical disk substrate. Optical means for irradiating the ultraviolet laser beam from the modulating means for processing and forming signal pits thereon, and the processing area on the optical disk substrate in the vicinity of the processing area, and the processing area from the rotation center side of the optical disk substrate. This is achieved by providing a supply nozzle that allows gas to flow toward, and a suction nozzle that is disposed at a position facing the supply nozzle with respect to the processing region and that suctions the gas that has flowed from the supply nozzle.

According to the above structure, the signal pits are directly processed on the optical disk substrate by using the ultraviolet laser light, and the air flow is generated in the processing area so that the processing waste is sucked together with the air flow. It is not necessary to perform the manufacturing work in a clean room having a high cleanness and a large space as in the conventional case, and it is possible to manufacture an optical disc having a high C / N of a reproduction signal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiments described below are preferred specific examples of the present invention,
Although various technically preferred limitations are given, the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

FIG. 1 is a side view showing the configuration of an embodiment of an optical disk manufacturing apparatus according to the present invention. In this optical disk manufacturing apparatus 10, a table 12 rotatably supported by a spindle motor 11 is arranged, and a He supply nozzle 1 for supplying helium to the upper portion of the table 12.
3. A vacuum suction nozzle 14 for sucking helium and a laser oscillator 15 for irradiating an ultraviolet laser beam are arranged. The laser oscillator 15 includes an ultraviolet laser light source 151,
Recording signal modulation optical system 152, signal pulse generation circuit 15
3, reflection mirror 154 and focus actuator 1
The objective lens 156 is provided with 55. The laser oscillating device 15 is arranged so that it can irradiate the surface of the optical disc substrate 1 mounted on the table 12 with ultraviolet laser light.

Here, as the ultraviolet laser light source 151, for example, a UV laser light source which emits a high energy density laser light having a wavelength of 280 nm or less is used. As a specific UV laser light source, for example, a light source that emits an ultraviolet laser light having a wavelength of 266 nm using the fourth harmonic generation of neodymium-yag (Nd: YAG) laser light having a wavelength of 1064 nm, that is, semiconductor excitation Nd: 1 YAG laser beam
There is a two-stage SHG element that converts to a / 4 wavelength. Also,
A light source that emits ultraviolet laser light having a wavelength of 266 nm using the fourth harmonic generation of Nd: YVO4 laser light having a wavelength of 1064 nm and a wavelength using the fourth harmonic generation of Nd: YLF laser light having a wavelength of 1047 nm are A light source that emits a 262 nm ultraviolet laser beam, the wavelength of which is 1079 nm N
d: The wavelength using the fourth harmonic generation of YAP laser light is 2
There is a light source that emits a 70 nm ultraviolet laser beam. The fourth harmonic laser light is single mode continuous wave laser light. In addition, the recording signal modulation optical system 15
Reference numeral 2 includes an acousto-optic element and a lens, and the intensity of the ultraviolet laser light from the ultraviolet laser light source 151 is modulated based on the pulse signal input from the signal pulse generation circuit 153 to the acousto-optic element. .

He supply nozzle 13 and vacuum suction nozzle 1
As shown in the side view of FIG. 2 and the plan view seen from below in FIG. 3, 4 is a position facing the objective lens 156 of the laser oscillating device 15, that is, facing a processing area on the optical disc substrate 1. At a position to be inserted, it is arranged so as to be inserted obliquely toward the processing region. In this way, each nozzle 13,
The reason for arranging 14 at a predetermined angle is that each nozzle 1
This is because it is possible to prevent the fluctuation of the ultraviolet laser light and to supply and suck helium more effectively when the tip ends of 3 and 14 are closer to the processing area, and the working distance of the objective lens 156 is 1 mm to This is because it is a very short and narrow area of 2 mm. Furthermore, helium diffuses in the horizontal direction, making it difficult to create a helium atmosphere. Therefore, it is desirable that the predetermined angle is, for example, 45 ° or more. The He supply nozzle 13 is arranged on the rotation center side of the optical disc substrate 1, and the vacuum suction nozzle 14 is provided.
Are arranged on the outer peripheral side of the optical disc substrate 1. The reason for this arrangement is that helium flows from the center of the optical disc substrate 1 toward the outer periphery due to the centrifugal force generated by the high-speed rotation of the optical disc substrate 1.

The nozzles 1 of the He supply nozzle 13 and the He suction port 131 of the He suction nozzle 14 and the suction port 141 of the vacuum suction nozzle 14 are arranged parallel to the surface of the optical disk substrate 1.
The tip portions of 3 and 14 are obliquely cut, and in consideration of the balance between the supply and the suction of helium, the suction port 141 is closer to the optical disc substrate 1 than the He blow port 131.
It is located slightly away from the surface of the. The reason for adopting such a shape is that the working distance of the objective lens 156 is a relatively short and narrow place of 1 mm to 2 mm, and that helium is diffused in the horizontal direction to make it difficult to create a helium atmosphere. . The He outlet 131 has an elliptical shape, and the suction opening 141 has an arc shape surrounding the objective lens 156.
The shape of the suction port 141 may be an elliptical shape like the shape of the He blowout port 131, but the arc shape makes it possible to suck helium at a wide angle.

An operation example of such a configuration will be described. The operator mounts the optical disk substrate 1 on the table 1
Then, the spindle motor 11 is driven to rotate the optical disk substrate 1 together with the table 12, and the laser oscillator 15 is activated. Here, as the optical disk substrate 1, for example, a substrate made of a synthetic resin material such as a polycarbonate resin is used. The light flux of the ultraviolet laser light emitted from the ultraviolet laser light source 151 is recorded by the recording signal modulation optical system 1.
The intensity of the light is modulated into a light modulation pulse based on the pulse signal which is incident on the beam 52 and is input from the signal pulse generation circuit 153. After that, the light beam emitted from the recording signal modulation optical system 152 is reflected by the reflection mirror 154 and enters the objective lens 156. Then, the focus is adjusted appropriately by the focus actuator 155, and the light is focused on the optical disc substrate 1 with a diffraction-limited spot size.

Here, the optical system including the objective lens 156 is synchronized with the rotation of the table 12 in synchronization with the optical disc substrate 1.
While the distance between the optical disc substrate 1 and the optical disc substrate 1 is kept constant, the optical disc substrate 1 moves in the radial direction from the outer periphery toward the center, so that the beam spot irradiated on the optical disc substrate 1 is spirally scanned. Then, by this irradiation, the optical disk substrate 1 is ablated, that is, ablated to form a groove which is a tracking guide pattern and a signal pit which is a recording signal groove. The metal film is the optical disk substrate 1
Is vacuum-deposited on the signal recording surface of and is coated with resin as a protective layer to obtain a final optical disc.

The laser ablation process is a process in which high-density photons of laser light are used to break chemical bonds on the material surface and evaporate. The output of the ultraviolet laser light for causing ablation is 0.1 MW / cm2
Although the above is required, 1 MW / cm 2 or more is preferable for practical use, and it depends on the types of the synthetic resin material and the photoresist material, but considering the rotation speed of the optical disk substrate 1 and the irradiation position of the ultraviolet laser light, etc. An energy density of 1 J / cm 2 is sufficient for the laser light. For example, the intensity of the ultraviolet laser light of the fourth harmonic having an output of 500 mW after passing through the objective lens 156 is 100 mW or more even when the optical system efficiency is taken into consideration. Therefore,
The linear velocity due to the rotation of the optical disk substrate 1 is 5 m / sec,
If the spot diameter of the ultraviolet laser light is 0.35 μm,
The energy density of the ultraviolet laser light when exposing the optical disk substrate 1 is about 6 J / cm 2, which is a sufficient value for causing ablation. Further, the size of the signal pit formed by ablation is determined by the intensity of the ultraviolet laser light, the spot diameter of the ultraviolet laser light, the modulation signal waveform, the rotation speed of the optical disc substrate 1, etc., so these values are controlled. Therefore, for example, the width is 0.4μ
Signal pits having a size of m, a length of 0.8 μm to 3.2 μm, and a depth of 0.1 μm can be directly processed on the optical disk substrate 1.

Here, in the above-mentioned laser ablation process, a large amount of fine processing debris (debris) is generated. Therefore, when the laser ablation process is performed in the air atmosphere, a large amount of debris is generated from the optical disc substrate 1 and adheres onto the optical disc substrate 1. This debris is 1 nm
Although the lumps have various sizes of ˜100 nm, when an optical disc with such debris attached is reproduced, the C / N of the reproduction signal is extremely deteriorated due to the influence, and normal data detection becomes difficult. Therefore, during the laser ablation process, helium is supplied to the He supply nozzle 13,
The supplied helium is ejected from the He outlet 131, and the ejected helium is ejected from the vacuum suction nozzle 14
Is sucked. As a result, a helium atmosphere is created in the vicinity of the processed area on the optical disk substrate 1, and debris generated in the processed area is diffused and diluted in a wider area than in the atmosphere, so that the debris drops and adheres to the optical disk substrate 1. Before it is carried, it is sucked into the vacuum suction nozzle 14 at a wide angle by riding on the flow of helium. As described above, since the debris does not grow into large particles due to diffusion and thinning, it is possible to prevent the debris from floating in the air and being attached to the optical disc substrate 1.

FIG. 4 is a side view showing another embodiment of the optical disk manufacturing apparatus of the present invention. Even if the He supply nozzle 13 for supplying helium, the vacuum suction nozzle 14 for vacuum sucking helium, and the laser oscillating device 15 for irradiating the ultraviolet laser light are arranged below the optical disk substrate 1, the same effect as described above is obtained. Produce an effect. Also in this case, the He supply nozzle 13 and the vacuum suction nozzle 14 are located in the processing area at positions facing each other with the objective lens 156 of the laser oscillator 15 interposed therebetween, that is, at positions facing the processing area on the optical disk substrate 1. It is placed diagonally toward you. The He supply nozzle 13 is arranged on the rotation center side of the optical disc substrate 1, and the vacuum suction nozzle 14 is provided.
Are arranged on the outer peripheral side of the optical disc substrate 1. Further, the tips of the nozzles 13 and 14 are obliquely cut so that the He outlet 131 of the He supply nozzle 13 and the suction port 141 of the vacuum suction nozzle 14 are parallel to the surface of the optical disc substrate 1. In consideration of the balance between supply of helium and suction, the suction port 141 is arranged at a position slightly distant from the surface of the optical disc substrate 1 rather than the He outlet 131. Although helium gas is used in each of the above-described embodiments, the atmosphere (nitrogen,
Any element (molecule) that is lighter and more inert than oxygen (e.g. oxygen) molecules may be used, and for example, hydrogen gas, neon gas, or the like can be used.

As described above, since the signal pits can be formed only by exposure, the conventional reproduction processing step, development processing step, etc. are unnecessary, and fluctuations and variations in the length of the signal pits are minimized. be able to. Further, since the adherence of debris to the optical disc substrate 1 at the time of forming signal pits can be significantly reduced, the deterioration of the C / N of the reproduced signal can be suppressed and the normal data reproduction can be performed. Therefore, it is possible to manufacture an optical disc having high signal recording accuracy with simple equipment. Furthermore, a predetermined program signal pit is already formed by injection molding, and additional information such as a manufacturing serial number is stamped by laser ablation processing on the optical disc substrate before the reflection film such as an aluminum film is formed. Using this as an identification ID for each optical disc is effective in preventing the occurrence of pirated copies.

[0021]

As described above, according to the present invention,
Since an optical disc with high signal recording accuracy can be manufactured with simple equipment, it is possible to reduce the number of steps and provide an optical disc with high added value at low cost.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of an optical disc manufacturing apparatus of the present invention.

FIG. 2 is a side view showing details of main parts of the optical disc manufacturing apparatus shown in FIG.

FIG. 3 is a plan view of a main part of the optical disc manufacturing apparatus shown in FIG. 2, viewed from below.

FIG. 4 is a side view showing details of essential parts of another embodiment of the optical disk manufacturing apparatus of the present invention.

[Explanation of symbols]

10 ... Optical disk manufacturing apparatus, 11 ... Spindle motor, 12 ... Table, 13 ... He supply nozzle, 14 ... Vacuum suction nozzle, 15 ... Laser oscillation device, 131 ... He Blow-off port, 141 ... Suction port, 151 ... Ultraviolet laser light source, 152 ... Recording signal modulation optical system, 153 ... Signal pulse generation circuit, 1
54 ... Reflective mirror, 155 ... Focus actuator, 156 ... Objective lens

Claims (2)

[Claims] 1. A laser light source for emitting an ultraviolet laser beam, a modulating means for modulating the intensity of the ultraviolet laser light from the laser light source, and the modulating means for processing and forming signal pits on a rotating optical disk substrate. Means for irradiating the ultraviolet laser beam from the optical disk substrate, a supply nozzle disposed in the vicinity of the processing area on the optical disk substrate, for supplying gas from the rotation center side of the optical disk substrate toward the processing area, and the processing area On the other hand, an optical disk manufacturing apparatus, comprising: a suction nozzle that is disposed at a position facing the supply nozzle, and that suctions gas flowing from the supply nozzle. 2. The optical disk manufacturing apparatus according to claim 1, wherein the gas is helium.