JPH06302016A - Optical disc substrate manufacturing method - Google Patents

Abstract

PURPOSE:To improve productivity by subjecting a master substrate to irradiation with UV rays then to a baking treatment. CONSTITUTION:A resist is applied on the main surface of the disk glass substrate and is developed after prebaking for 60 minutes at 60 deg.C and laser cutting. The glass substrate 2 is placed on a stage 1 movable in arrow X direction and the resist is irradiated with UV rays from a UV ray source 3 which faces the substrate and is parted therefrom at a prescribed distance for 30 seconds in N2. Then, the resist is baked for 3 hours at 200 deg.C, thereby increasing the adhesive force between the glass and the resist. The adhesive force of the glass and the resist is increased in such a manner and, therefore, the sticking of the resist is averted at the time of peeling a stamper from the master substrate is averted. The master substrate is reusable many times. Then, plural stampers having the same characteristics are produced from one sheet of the master substrate. The assurance of the quality is also smoothly managed. Since the stages from precision washing to developing are omitted in the production process of the stamper, the productivity is greatly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk substrate manufacturing method for manufacturing an optical disk stamper.

[0002]

2. Description of the Related Art For example, an optical disk stamper used for manufacturing an optical disk, a magneto-optical disk or the like by the 2P method is manufactured according to the following procedure. First, as shown in the flowchart of FIG. 4, in step ST101, the glass substrate to be the master is precisely cleaned.

Next, in step ST102, the glass substrate is baked. Subsequently, in step ST103, a resist is applied to one main surface of the glass substrate.

Then, the glass substrate is subjected to step ST.
After prebaking in 104, the signal information is laser-cut in step ST105. Next, step ST
Develop at 106. As a result, the resist in the portion corresponding to the preformatted data pattern is removed.

Then, in step ST107, 100 ° C.
Post bake at 60 minutes. After that, step S
Electroless plating is performed at T108, and then step ST1
Electroplating is performed at 09. Next, after polishing the back surface of the glass substrate in step ST110, the stamper is peeled off from the glass substrate.

Next, in step ST111, the resist attached to the stamper is removed. As a result, step ST
A stamper is made at 112.

Incidentally, in order to regenerate the glass substrate in step ST113, Ni is removed in step ST114. Then, after alkali treatment in step ST115, polishing is performed in step ST116 to regenerate the glass substrate. Reclaimed glass substrate, step ST10
Returning to step 1, the above steps are sequentially repeated and the stamper is manufactured again.

[0008]

By the way, in the present process, since the adhesion between the glass substrate and the resist is insufficient, the resist layer is removed when the stamper is peeled from the cut glass substrate (resist master). Was destroyed,
There is a disadvantage that it adheres to the stamper. Therefore, a step of dissolving the resist attached to the stamper with acetone or the like after peeling is required.

As described above, according to the above-described manufacturing method, only one stamper can be manufactured from one glass substrate, which is extremely disadvantageous in mass production of the stamper, and the steps from precision cleaning to development. (Step ST101-
Man-hours (processes up to step ST106) (about 3 days)
Takes.

Therefore, the present invention has been proposed in view of the above conventional circumstances, and provides an optical disk substrate of high quality and excellent productivity that allows a plurality of stampers having the same characteristics to be manufactured from one master substrate. It is intended to provide a manufacturing method.

[0011]

In order to achieve the above object, the present invention uses a glass substrate on which signal information is recorded by laser cutting in advance as a master substrate, and an optical disk stamper is manufactured by transferring from the master substrate. In the method for manufacturing an optical disc substrate described above, the master substrate is subjected to ultraviolet irradiation and baking treatment after laser cutting and developing treatment.

[0012]

In the present invention, when the master substrate subjected to the laser cutting / developing treatment is irradiated with ultraviolet rays, the photoresist is polymerized and polymerized. Subsequently, when this is baked, the adhesion between the glass and the resist is enhanced. Therefore, even if the stamper is subsequently peeled off from the master substrate, the resist does not adhere to the stamper, and the master substrate can be reused many times.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. In this embodiment, a manufacturing process of an optical disk substrate will be described with reference to the flowchart shown in FIG.

In order to manufacture an optical disk substrate to be an optical disk stamper, first, in step ST1, a disk-shaped glass substrate (diameter 220 mm) is precisely cleaned. Specifically, IPA drying is performed after the silane treatment. Next, in step ST2, glass baking is performed under the conditions of 120 ° C. and 120 minutes.

Next, in step ST3, a resist is applied to one main surface of the glass substrate. When applying the resist, baking after UV irradiation, which is performed in the process described below, is required.
Since it is quite hard at 00 ° C, the film thickness of the photoresist is taken into account and the resist is applied a little thicker. In the method so far, it is 103 ± 1 nm, but in this embodiment, it is about 108 ± 1 nm.

Next, the glass substrate on which the resist has been formed in step ST4 is prebaked under the conditions of 60 ° C. and 60 minutes. Then, in step ST5, the signal information is laser-cut. Next, in step ST6, development is performed. Then, the resist in the portion corresponding to the preformatted data pattern is removed.

After the development is completed, step ST7
Ultraviolet rays (UV) are radiated in N ₂ for about 30 seconds on the resist remaining in step ₂ . When irradiating with ultraviolet rays, as shown in FIG. 2, the glass substrate 2 after development is mounted on the stage 1 (400 × 400 mm) which is movable ± 25 mm in the left-right direction indicated by the arrow X. Glass substrate 2
The resist on the glass substrate 2 is irradiated with ultraviolet rays from a light source 3 provided facing each other with a predetermined distance.

As the light source 3, seven 100 W low pressure straight tube mercury lamps with a short wavelength of 185,254 nm are used. For example, in this device, the glass substrate 2 has a thickness of 10 mm.
And the light intensity when the facing distance between the light source 3 and the upper surface of the glass substrate 2 on which the resist is formed is 15 mm,
It becomes 7-8 mW / cm ² . The irradiation amount of ultraviolet rays at this time becomes 210 to 240 mJ / cm ^{2 after} irradiation for about 30 seconds.

The amount of N ₂ is, for example, about 20 to 50 liters / minute, and the introduction pressure is about 3 kg / cm ² .
In addition, the cooling water (5
L / min) is flushed.

When the resist is irradiated with ultraviolet rays, the photoresist is polymerized and polymerized. As a result, harder baking conditions are possible in the post-baking 1 in the next step.

Then, in order to increase the adhesion between the glass and the resist, the temperature (10
Baking is performed under the condition of twice (0 ° C.), that is, 200 ° C. for 3 hours. Baking is N ₂ flow 20 liters /
The UV-irradiated glass substrate 2 is placed in a glass case under an introduction pressure of 3 to 5 kg / cm ² and baked with the lid kept. As shown in FIG. 3, the temperature is raised to 200 ° C. in about 1 hour, kept at that temperature for 3 hours, and then cooled to room temperature in 5 to 6 hours with nitrogen,
Save as is. In FIG. 3, the broken line indicated by A indicates the actual temperature state.

By performing the ultraviolet irradiation and the baking treatment, the adhesion between the glass and the resist is enhanced.

Next, chemical plating is performed, but since the resist surface is hydrophobic because the post-bake is strengthened, the chemical plating pretreatment is performed with about 1N-HCl in step ST9. Make the resist surface hydrophilic. Then, a hydrophilic catalyst (catalyst 9F) is applied and activated with an accelerator.

Then, in step ST10, chemical plating is performed. Chemical plating, when performing electrolytic plating in the next step,
This is done in order to energize the electrodes. The electroless plating is performed from the side surface of the glass substrate 2 to a part of the back surface thereof, and the resist surface is plated with 1000 liters.

Next, in step ST11, electroless plating for forming a stamper is performed. In this embodiment, the electroless plating is made to have a thickness of 300 mm.

Next, in step ST12, the glass substrate 2
The back surface of is polished (lapping) to remove the plating for energizing the electrodes. Then, in step ST13, the stamper is peeled off from the glass substrate 2. At this time, since the resist is firmly fixed to the glass substrate 2, even if the stamper is peeled from the glass substrate 2, the resist does not remain on the stamper. That is, the resist is still provided on the glass substrate 2.

Next, the produced stamper is subjected to step S.
The resist is washed at T14. The resist is washed with acetone. This completes the first stamper. In addition,
For the stamper drying method, use acetone to IPA
And shake off at high speed (500 rpm) to dry.

Then, after checking the thickness of the stamper produced in step ST15, a defect check for checking the unevenness of the stamper surface is performed in step ST16. Next, in step ST17, a 2P disc is formed, and then in step ST18, a signal check is performed for actually driving the drive to check the signal.

Next, the stamper is completed by trimming in step ST19.

On the other hand, the glass substrate 2 from which the stamper has been peeled off
Is reproduced according to the following procedure. In this example,
The glass substrate 2 after laser cutting and developing is referred to as a glass master after step ST20. Since the glass master is insoluble in solvents, step ST
Acetone wash at 21 and IPA spin dry.

Next, in step ST22, a protective film (clean coat S) is applied to the resist surface. This is to eliminate the effects (stains, etc.) of salt iron. Next, in step ST23, Ni is removed. It is soaked in a ferric chloride solution for about 1-2 hours to remove Ni on the edges and back of the glass master. Then, in step ST24, the protective film is peeled off, and in order to wash the rest of the protective film and the like, IPA spin drying is performed again in step ST25.

Next, in step ST26, post bake 2 is performed.
I do. Here, the glass master is rebaked under the conditions of 200 ° C. and 3 hours. Finally, in step ST27, pretreatment for chemical plating is started. Since the end surface of the glass master is once shaved, silane (about 0.1%) is soaked in with bencot and the end surface and the back surface are rubbed by hand.

After that, the above step ST to which hydrochloric acid was added
Process 9 is performed, and then chemical plating is started. Further, the process from the electroplating in step ST11 to the peeling of the stamper in step ST13 is repeated to manufacture the second stamper. The second stamper produced has the advantage that it has the same characteristics because it is obtained by being transferred from the same glass master that produced the first stamper.

By repeating the above flow, it is possible to efficiently manufacture a plurality of stampers having the same characteristics. That is, it is possible to reduce the cost of the process from the precision cleaning in step ST1 to the development in step ST6, the time (which takes about 3 days), and the like, and as a result, the cost of the stamper can be reduced.

Actually, the diameter is set to about 64 mm,
A stamper used for manufacturing an optical disk or a magneto-optical disk capable of recording about 74 minutes with a tone signal was manufactured according to the above-mentioned flow. As a comparative example, similar stampers were manufactured by a conventional method, and the signal characteristics of these stampers in 2P evaluation were examined.
The results are shown in Table 1. In Table 1, PP indicates the width of the groove or pit, and RC indicates the height of the groove or pit.

[0036]

[Table 1]

As can be seen from these results, by controlling the resist thickness and the laser cutting conditions, the signal characteristics equivalent to those of the conventional stamper were obtained.
Further, the signal characteristics of the first sheet and the second sheet of the stamper produced by the glass master according to the present invention are substantially the same, and it can be seen that the reproducibility is very good. Also,
The groove shape is much smoother than that of the conventional product in SEM observation. This is considered a hard baking difference.

The specific embodiments to which the present invention is applied have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the method of the present invention can be applied to manufacture of a stamper used in manufacturing all kinds of optical disks such as a 5.25-inch magneto-optical disk, a 3.5-inch magneto-optical disk, and a write-once optical disk.

[0039]

As is clear from the above description, according to the method of the present invention, the master substrate which has been subjected to the laser cutting / developing treatment is irradiated with ultraviolet rays and then subjected to the baking treatment. The adhesion to the stamper is increased, the resist is prevented from adhering to the stamper when the stamper is peeled from the master substrate in the subsequent step, and the master substrate can be reused many times.
Therefore, it is possible to manufacture a plurality of stampers having the same characteristics from one master substrate, and it is possible to smoothly manage the quality assurance of the process.

Further, according to the method of the present invention, the steps from the precision cleaning to the development in the stamper manufacturing process can be omitted, and the productivity can be greatly improved. Further, the cost of the stamper, which has been expensive until now, can be significantly reduced by using the present invention.

[Brief description of drawings]

FIG. 1 is a flow chart diagram sequentially showing steps of manufacturing a stamper.

FIG. 2 is a diagram showing a step of irradiating a resist with ultraviolet rays in a step of manufacturing a stamper.

FIG. 3 is a diagram showing a processing temperature and time in a baking processing step after laser cutting in a step of manufacturing a stamper.

FIG. 4 is a flowchart sequentially showing steps of manufacturing a stamper by a conventional method.

[Explanation of symbols]

 1 ... Stage 2 ... Glass substrate 3 ... Light source

Claims (1)

[Claims] 1. A method of manufacturing an optical disk substrate, wherein a glass substrate on which signal information is recorded by laser cutting in advance is used as a master substrate, and an optical disk stamper is manufactured by transfer from this master substrate, wherein the master substrate is laser cutting / developing. After the treatment, an ultraviolet ray irradiation and a baking treatment are applied to the optical disc substrate manufacturing method.