JPH0461643A - Production of optical master disk - Google Patents

Abstract

PURPOSE:To obtain less defect errors, higher quality and lower cost by using the optical master disk which is formed by transferring the grooves on a substrate to a metallic material layer and forming ruggedness on the transferred grooves as a stamper for molding optical disks. CONSTITUTION:The V grooves of high accuracy are formed on the surface of the disk substrate 1 and the metallic material layer 8 is formed on the disk substrate 1 subjected to the V grooving; thereafter, this layer is peeled from the substrate 1, by which the V grooves of the substrate 1 are transferred to the metallic material layer 8. A positive type resist 3 is then applied on the surface of the metallic material 8 transferred with the V grooves. The positive type resist 3 on the slopes of the V grooves is partly exposed to provide exposed pats 4 corresponding to recording signals. The ruggedness is formed after the exposed parts 4 are removed. The positive type resist 3 remaining on the surface of the disk substrate 1 is thereafter removed to obtain the master disk. This master disk is used as the stamper for molding the disks. The less defect errors, the higher quality and the lower cost are obtd. in this way.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a method of manufacturing a master disc of an optical disc such as a compact disc or a video disc. It is commercially available,
For information on the manufacturing method of disc masters, please refer to the Journal of the Japan Society for Precision Engineering (Materials and manufacturing technology of optical discs = 54/12/7 - 10/19
Even if it is stated in 88) etc. = V-shaped groove (
A high-density recording method (Japanese Patent Laid-Open No. 105828/1983) that improves recording density by forming unevenness on the slope of the groove (hereinafter referred to as ``groove'').
(see Japanese Patent Laid-Open No. 61-23), and a manufacturing method for disc masters to lower the error rate has been proposed.
(See Publication No. 6049).

Hereinafter, an example of a conventional disk master manufacturing method will be explained with reference to FIGS. 3 and 4.
) to (e), 1 is a disk substrate 2 is a cutter 3
4 is a positive resist, and 4 is an exposed part of a positive resist 3.As shown in FIG. 3(a), the surface of a disk substrate 1, which is a copper plate formed by electrolytic copper plating, is processed with a knife 2. A positive resist 3 is applied to the surface of the disk substrate 1 on which the LV grooves have been formed, as shown in FIG. 1(C). A part of the positive resist 3 is exposed by irradiation with a light beam corresponding to the signal to be recorded.Positive resist 3
The exposed portion 4 of the resistor was removed using a solution.
The slopes of the grooves are etched to form unevenness, that is, signal bits, as shown in FIG. Remove the same figure (
To obtain a disc master as shown in e), a stamper is manufactured from the optical disc master obtained in this way by electrolytic nickel plating, and the surface shape of the stamper is used to make a resin disc (hereinafter referred to as a disc) of acrylic or polycarbonate. Even if optical discs are manufactured using injection molding method or ultraviolet curable resin method, which transfers the image onto a disk (called ``transfer''), an example of a conventional method for manufacturing a disk master to reduce the error rate is shown in Figure 4, which shows the manufacturing process. In (a) to (e), 5 is a glass substrate, 6 is a negative resist, 7 is a negative resist 6
As shown in FIG. 4(a), a negative resist 6 is applied to the surface of the glass substrate 5 in the exposure area of FIG.
As shown in b), the signal is exposed by irradiation with a light beam corresponding to the signal to be stored, and as shown in the same figure (c), the negative resist 6 other than the exposed area 7 is removed with a solution and recorded Form unevenness on the resist layer corresponding to the signal and use an inert gas such as argon or CHF5, CFJ, C
By a sputter etching method using a reactive gas such as Cl4, an uneven pattern having the same pattern as that of the negative resist 6 is formed on the glass substrate 5 as shown in FIG. 4(d). After that, the glass substrate 5 is ashed using oxygen or the like or a solution is used.
The exposed portion 7 of the negative resist 6 remaining on the surface of the glass substrate 5 is removed, and as shown in FIG. However, problems with the prior art include the number of irregularities transferred from the disc master to the stamper, and the number of times the irregularities are transferred from the stamper to the disc. The number of defect errors increases, causing a decline in the signal quality of the disc.In other words, as the number of transfers increases, the number of defect errors also increases.Deterioration in signal quality is a major problem, especially for optical discs that reproduce high-definition television signals. .

Second, when a resist coated on the surface of a highly reflective substrate such as aluminum or nickel is exposed by light beam irradiation, partial underexposure may occur due to the return light from the substrate surface. However, in order to minimize the influence of returned light, it is necessary to control the thickness accuracy of the GQ resist to about 0.01 μm.
It is difficult to satisfy this accuracy over the entire disk substrate.Thirdly, it is necessary to form unevenness directly on the surface of the glass substrate that corresponds to the recorded signal.When reusing the glass substrate, polishing of the substrate surface is necessary. This is especially true for disk substrates using V-grooves, which requires precise V-groove machining each time.
The present invention solves the above-mentioned problem, which has been a factor in the increase in the manufacturing cost of disc masters.It is an object of the present invention to provide a method for manufacturing high-quality optical disc masters with few defect errors at a low cost. Means for achieving the above object The present invention forms a metal layer on the surface of a grooved disk substrate and then separates the disk substrate to transfer the grooves of the disk substrate to the metal layer side. The grooves transferred to the layer are used as a disc master by forming irregularities on the grooves, and in order to further improve the transferability, a release material is formed on the surface of the disc substrate, and a metal layer is formed on the surface of the release material. In addition, a glass material with high viscosity and a low melting point is placed on the surface of the release material, and the glass material is pressed against the release material with a constant force to form irregularities in the grooves of the disk substrate transferred to the glass material. The disc master is manufactured using the same method.

According to the present invention, grooves are transferred from a grooved disk substrate to a metal material layer or a glass material, and unevenness corresponding to a recording signal is formed in the grooves of the metal material layer transferred from the disk substrate, and this is immediately transferred. The unevenness formed in the grooves of the substrate is transferred directly to the -H nickel layer, etc., and then transferred to the disk.The unevenness is transferred only once, reducing defect errors. In addition, by using a glass material with extremely high transmittance, it is possible to reduce the amount of light returned from the substrate surface during resist exposure by irradiating a light beam, and it is possible to improve the problem of underexposure due to interference. Further, according to the present invention, since it is possible to transfer a disk substrate with precise grooves many times as a master, it is possible to provide a disk master disk with low manufacturing cost. This will be explained with reference to the drawings and FIG. 2 (Example 1) In FIG. 1, 1 is a disk substrate, 2 is a blade end 3 is a positive resist, and 4 is for exposure of the positive resist 3. 8
indicates a metal material layer. The disk substrate 1 formed by the electrolytic copper plating method is rotated at a constant rotation speed, and as shown in FIG. 1(a).
As shown in the figure, the surface of the disk substrate 1 has a tip angle of 165
With the blade 2 of about
V-groove processing is performed by moving at a constant speed in the radial direction of the disk substrate 1 to form highly accurate V-grooves with a groove pitch of about 2 μm on the surface of the disk substrate 1, as shown in FIG. Using the disc substrate 1 as an electrode, place it in an electrolytic solution. After forming a metal layer 8 made of a material such as silver on the surface of the disk substrate 1 as shown in FIG.
After transferring the V-groove, a positive-type resist 3 is applied to the surface of the metal material 8 onto which the V-groove has been transferred, and a part of the positive-type resist 3 on the slope of the LV groove is exposed by irradiation with a light beam, as shown in FIG. As shown in the figure, an exposed area 4 corresponding to the recording signal is provided. After removing the exposed area 4 with a solution, a part of the V-groove slope is etched by an ion milling method using an inert gas such as argon, as shown in FIG. As shown in the figure, although unevenness is formed, the positive resist 3 remaining on the surface of the disk substrate 1
This disk master is removed by an ashing method using oxygen to obtain a disk master as shown in FIG.

In the above case, the metal material layer 8 can be formed by electrolytic plating, bus sputtering, or ion beam method (Example 2) In the case where the groove pitch is extremely narrow, FIG. 1 of Example 1 (
A release material is formed on the surface of the disk substrate 10 which has been grooved as shown in b). It was confirmed that this further improved the transferability of the grooves and was effective in suppressing the occurrence of defect errors during processing. The process shown in FIG. 2 is basically the same as the manufacturing process of the optical disk master shown in FIG. 1, so the same components are given the same numbers and detailed explanations are omitted. 1 is a disk substrate, 2 is a blade 3 is a positive resist, 4 is an exposed part of the positive resist, 9 is a release material, 10 is a glass material with high viscosity and a low melting point, 11 is a glass substrate with a ■groove A release material 9 made of nickel, oxide, tungsten, etc. is formed on the surface of the disk substrate 1 on which a high viscosity is formed, as shown in FIG. 2(b), by sputtering or ion beam method. Place the glass material 10 with a low melting point at
As shown in FIG. 6(c), the V-groove is transferred to the glass material 10 by pressing the glass material 10 against the release material 9 with a constant force using the glass substrate 11. Thereafter, the V-groove is transferred to the glass material 10. A positive resist 3 is applied to the surface. A part of the positive resist 3 on the slope of the LV groove is exposed by irradiation with a light beam.An exposure section 4 corresponding to the recording signal is provided as shown in FIG. Inert gas such as argon or CHF3, CFa, CC1a
By sputter etching method using reactive gas such as
■After forming unevenness on the slope of the groove as shown in Figure (e), the positive resist 3 remaining on the surface of the glass material 10 is removed by ashing using oxygen or a solution as shown in Figure (f). Obtain an optical disc master such as .

Effects of the Invention Using this Optical Disc Master as a Standby for Disk Molding As is clear from the above-described embodiments, the present invention provides an optical disc master in which the grooves are transferred to a metal or glass material and unevenness is formed in the transferred grooves. It is possible to obtain high-quality optical discs by reducing defect errors caused by missing unevenness during transfer.Also, it is possible to transfer multiple times from a single disc substrate with precision groove processing. In fact, it may be possible to significantly reduce the manufacturing cost of optical disc masters.

[Brief explanation of drawings]

Figures 1 (a) to (f) are manufacturing process diagrams of an optical disc master according to one embodiment of the present invention @ Figures 2 (a) to (f) are manufacturing process diagrams of an optical disc master according to another embodiment of the present invention
3(a) to 3(e) are diagrams showing one manufacturing process of a conventional optical disk master. FIGS. 4(a) to (e) are diagrams of another manufacturing process of a conventional optical disc master. ...Knife 3...Positive resist, 4...Exposed part of positive resist 8...
・Name of Metal Materials Agent: Patent Attorney Shigetaka Awano 1 box 2 drawings! Friends of the School

Claims (3)

[Claims] (1) A method for producing an optical disk master by forming a metal layer in a groove formed on the surface of a disk substrate, forming irregularities in the groove transferred from the disk substrate in the metal layer, and using the metal layer as a disk master. (2) Form a surface layer of release material in the grooves formed on the surface of the disk substrate, form a metal layer on the surface layer of the release material, and form irregularities in the grooves transferred from the disk substrate of the metal layer. A method of manufacturing an optical disc master by forming a disc master. (3) Form a surface layer of release material in the grooves formed on the surface of the disk substrate, place a high viscosity, low melting point glass material on the surface layer of the release material, and place the glass material on the surface of the release material. A method for producing an optical disc master by pressing the layer with a constant force to form irregularities in the grooves transferred from the glass disc substrate to obtain a disc master.