JP2006079686A - Method of manufacturing glass master - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a glass master in which a rough surface on a side wall of a groove is not generated. <P>SOLUTION: After photoresist 2 is applied on a glass substrate 1 and the photoresist 2 is exposed using a laser beam of wavelength shorter than absorption wavelength of the photoresist 2, development is performed and a photoresist pattern 4 is formed, the glass substrate 1 is etched by using a photoresist pattern 4 as a mask. In forming a groove 5, after the groove 5 is formed, dry etching is performed at applied voltage of 50-500V under 0.5 Pa-5Pa ambient gas using fluorocarbon based gas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a glass master used for forming an optical disc such as a CD or a DVD.

In general, an optical disc capable of storing high-density data as an audio, image application, or computer memory is manufactured using a glass master.
A method for manufacturing an optical disk using a conventional glass master is described in Patent Document 1.

That is, after forming a photoresist pattern on the glass substrate, the glass substrate is plasma-etched using the photoresist pattern as a mask to form a rectangular groove having a width substantially the same as the bottom width. The photoresist pattern is removed to prepare a glass master. Further, a Ni film is formed on the groove of the glass master, and Ni electroforming is performed to peel off the Ni layer from the glass master to produce a master. An oxide film is formed by performing an oxide film treatment on the surface of the Ni film of the master. After forming an Ni layer on the oxide film by a nickel electroforming method, the Ni layer is peeled off from the master and the mother stamper is formed. Is made. An optical disk is manufactured by injection molding using this mother as a stamper.
Japanese Patent Laid-Open No. 11-296915

However, since the laser light has a high Gaussian distribution at the center and a low Gaussian distribution on the outside, the groove portion has a problem that the bottom portion is flat but the side wall is rough. In particular, when a laser beam having a wavelength of 266 nm is used as a light source in a Blu-ray cutting machine and the photoresist is for i-line (absorption wavelength 365 nm), the roughness of the groove side wall is particularly severe.
This is shown in FIG. FIG. 3 is a diagram showing a rough state of the side wall of the groove when the i-line photoresist is irradiated with laser light having a wavelength of 266 nm in the glass master produced in the conventional example.
As a result, the optical disk produced using the glass master described above could not be tracked or generated groove noise.

  Then, this invention is proposed in view of the above-mentioned subject, Comprising: It aims at providing the manufacturing method of the glass original disc which does not produce a rough side wall of a groove.

  In the present invention, a photoresist is coated on a glass substrate, the photoresist is exposed using laser light having a wavelength shorter than the absorption wavelength of the photoresist, and then developed to form a photoresist pattern. The glass substrate is etched using the photoresist pattern as a mask to form a groove. After forming the groove, a fluorocarbon-based gas is used to form a groove under an atmosphere gas of 0.5 Pa to 5 Pa. The method for producing a glass master is characterized in that dry etching is performed at an applied voltage of 50 to 500V.

  According to the present invention, after forming the groove, dry etching is performed using an fluorocarbon-based gas at an applied voltage of 50 to 500 V under an atmosphere gas of 0.5 Pa to 5 Pa. Is obtained. As a result, an optical disk manufactured using this glass master can obtain a good tracking error and reduce groove noise.

Hereinafter, an embodiment of a method for producing a glass master according to the present invention will be described in detail with reference to FIGS.
FIG. 1 is a cross-sectional view showing a method for manufacturing a glass master according to an embodiment of the present invention. FIG. 2 is a diagram showing a rough state of the side wall of the groove when a laser beam having a wavelength of 266 nm is irradiated onto the i-line photoresist in the glass master manufactured using the embodiment of the present invention.

(Latent image forming process)
As shown in FIG. 1A, after cleaning and drying the optically polished quartz glass substrate 1 having a diameter of 200 nm, an i-line photoresist 2 is applied, and then laser light having a wavelength of 266 nm is applied to the lens. To form a latent image 3.

(Groove formation process)
Thereafter, as shown in FIG. 3B, the latent image 3 is exposed and developed to form a photoresist pattern 4.

(Etching process)
Next, as shown in FIG. 3C, the photoresist pattern 4 is used as a mask, and an anisotropy is applied by applying a voltage of 100 V to 700 V under an atmosphere gas of 0.3 Pa to 3 Pa using a fluorocarbon-based gas. The groove 5 is formed by performing high dry etching.

(Groove sidewall treatment process)
Next, as shown in FIG. 4D, after oxygen ashing is performed and the photoresist pattern 4 is removed, a fluorocarbon-based gas is used again under an atmosphere gas of 0.5 Pa to 5 Pa at 50 to 500 V. A glass master 6 is manufactured by applying a voltage to reduce the roughness of the side wall of the groove 5.
Here, CF ₄ , CHF ₃ , C ₃ F ₈ , C ₄ F ₈ or the like is used as the fluorocarbon-based gas.
However, in the case of 5 Pa or more, the etching rate does not increase and etching cannot be performed with C ₃ F ₈ or C ₄ F ₈ . On the other hand, at 0.5 Pa or less, the groove side wall becomes rough. For this reason, when it is 0.5 Pa-5 Pa, when the fluorocarbon type gas is used, the roughness of the side wall of the groove 5 can be reduced.
This is shown in FIG.

  A stamper and an optical disk using the glass master 6 can be manufactured by a known manufacturing method.

  As described above, according to the embodiment of the present invention, after the groove 5 is formed on the glass substrate 1 using the etching gas, the fluorocarbon-based gas is used under the atmosphere gas of 0.5 Pa to 5 Pa. Since the applied voltage is dry-etched at 50 to 500 V, the glass master 6 with reduced roughness of the side wall of the groove 5 is obtained. As a result, an optical disk manufactured using this glass master 6 can obtain a good tracking error and reduce groove noise.

It is sectional drawing which shows the manufacturing method of the glass original disk which concerns on embodiment of this invention. It is a figure which shows the rough state of the side wall of a groove at the time of irradiating the laser beam with a wavelength of 266 nm to the photoresist for i rays in the glass master disc produced using embodiment of this invention. It is a figure which shows the rough state of the side wall of a groove at the time of irradiating the laser beam with a wavelength of 266 nm to the photoresist for i rays in the glass master disc produced by the prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Photoresist, 3 ... Latent image, 4 ... Photoresist pattern, 5 ... Groove, 6 ... Glass master

Claims (1)

A photoresist is applied on a glass substrate, and after exposing the photoresist using a laser beam having a wavelength shorter than the absorption wavelength of the photoresist, development is performed to form a photoresist pattern. Etching the glass substrate using a resist pattern as a mask, in the method of manufacturing a glass master to form a groove,
A method for producing a glass master, wherein after forming the groove, dry etching is performed using a fluorocarbon-based gas at an applied voltage of 50 to 500 V under an atmosphere gas of 0.5 Pa to 5 Pa.

Images