JPS6350937A - Formation of master disk for planar information recording carrier - Google Patents

Abstract

PURPOSE:To eliminate the need for a stage for forming a master disk for an optical disk made of a metal from a glass substrate by acting a plasma gas on a flat plate metallic substrate and forming the master disk for the optical disk directly therefrom. CONSTITUTION:A photoresist 2 is uniformly coated on the surface of a Cr substrate 7 and while the substrate 7 is rotated, the resist 2 is projected with the laser light 3 subjected to modulation corresponding to the structure of desired pit arrays and grooves. The exposed regions of the resist 2 are removed and rugged patterns appear when the resist is developed. The substrate 7 is then subjected to etching by using gaseous CCl4 and the etching is progressed down to a prescribed depth. The remaining resist 2 is thereafter removed by plasma ashing 4 using gaseous O2, then the substrate 7 inscribed with the prescribed concentrical or spiral grooves and pit arrays on the surface is obtd. An optical disk substrate 6 is reproduced therefrom by a method such as injection molding.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing a master disc of a flat information recording carrier having grooves or pit rows.

BACKGROUND OF THE INVENTION Etching technology for forming fine patterns on the surface of a substrate has become an indispensable technology for manufacturing semiconductor integrated circuits, printed circuit boards, transparent conductive films, and information recording media such as optical disks.

Particularly recently, dry etching processes have been attracting attention due to demands for finer patterns and automation of processes. Dry etching processes have already been put into practical use in the production of VLSIs, but this technology has also been incorporated into the production of optical disk substrates in which even finer submicron patterns are formed.

Hereinafter, with reference to FIG. 2, a method of forming a pattern on an optical disk substrate by dry etching will be explained.

First, a photoresist 2 is uniformly applied to the highly precisely polished surface of the glass substrate 10 (FIG. 2(a)). Then, while rotating the glass substrate 1, the photoresist 2 is irradiated with a laser beam 3 modulated in accordance with the desired structure of pit rows and grooves (FIG. 2(b)). By developing this, the exposed area of the photoresist 2 is removed, and a concentric or spiral uneven pattern appears on the surface (FIG. 2(C)).

Next, the glass substrate 1 is etched by applying gas plasma 4 to the uneven patterned glass substrate. Cu73 or the like is used as the etching gas.

After etching progresses to a predetermined depth (Fig. 2 ((i)
)) If the remaining photoresist 2 is removed by plasma ashing using 02 gas, a glass substrate with predetermined concentric or spiral grooves or pit rows carved on the surface can be obtained (see Fig. 2(e)). )).

By electroforming Ni or the like on the surface of this glass substrate and peeling it off, the optical disk master 5 is obtained (
Figure 2 (wa). The optical disk substrate 6 is reproduced based on this master by a method such as injection molding (FIG. 2(g)).

Problems to be Solved by the Invention In the conventional method, grooves are formed on a glass substrate, so it is necessary to create a metal master from this glass substrate in order to use it in a disk duplication process where large forces are applied, such as injection molding. It was necessary.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention forms grooves or pit rows by applying plasma-like gas to a flat metal substrate, and uses this directly as an optical disc master. It is.

action The effect of this means is as follows.

If a photoresist mask is provided on a metal substrate and a plasma-like gas is applied to the photoresist mask, etching of the metal substrate proceeds in the same way as a glass substrate, and grooves are formed on the surface. If this is used, the 6-page process of creating a metal disk master from a glass substrate as in the past becomes unnecessary.

Embodiment An embodiment of the present invention will be described with reference to FIG.

First, a photoresist 2 is uniformly applied to the highly precisely polished surface of the Or substrate 7 (FIG. 1 (IL)).

Then, while rotating the Or substrate 7, the photoresist 2 is irradiated with a laser beam 3 modulated in accordance with the desired structure of pit rows and grooves (FIG. 1(b)).

By developing this, the exposed area of the photoresist 2 is removed, and a concentric or spiral uneven pattern appears on the surface (FIG. 1(C)).

Next, CCl
Etching is performed using 4 gases. After etching has progressed to a predetermined depth (Fig. 1(d)), the remaining photoresist 2 is removed by plasma ashing using 02 gas, thereby forming predetermined concentric or spiral grooves or pits on the surface. An Or substrate 7 with rows carved therein is obtained (first
Figure (e)). Based on this, the optical disk substrate 6 is reproduced by a method such as injection molding (FIG. 1(0)).

Note that the etching gas used in this example was aaa4.
In addition, OH2C12* B' 65 or CCl4
A mixed gas of 0□ and 0□ can be used. Further, as a substrate, in addition to Or in this embodiment, Ni and Mul.

Ti, Co, Fe, Mo, W, Si, Cu, etc., and alloys containing these as main components can be used.

Effects of the Invention As described above, the present invention creates a metal disc master from a conventional glass substrate by directly creating an optical disc master by applying plasma-like gas to a flat metal substrate. The process can be omitted.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing a method for producing a master disk for a flat information recording carrier according to an embodiment of the present invention, and FIG. 2 is a process diagram showing a conventional method for producing a master disk for an optical disk. 1...Glass substrate, 2...Photoresist, 3...Laser light, 4...Incidence direction of gas plasma, 7 Page 5... . . . Optical disk master disc, 6 . . . Optical disk substrate, 7 . . . Or substrate. Name of agent: Patent attorney Toshio Nakao and 1 other person
d A to 6 to 0
8 phrases also +-1
++J ′ Fig. 2 (in IN -4 (εn (earth)

Claims (3)

[Claims] (1) A step of providing a photoresist having concentric or spiral openings on the surface of a flat metal substrate, and applying a gas in a plasma state to the flat metal substrate to form grooves corresponding to the openings. 1. A method for producing a master disc for a flat information recording carrier, the method comprising the step of forming a pit row. (2) In the flat metal substrate, at least the portion where the groove or pit row is formed is made of Cr, Ni, Al, Ti, Co, or Fe.
2. A method for producing a master disc of a flat information recording carrier according to claim 1, wherein the master disc is made of a material containing at least one of the following as a main component: , Mo, W, Si, and Cu. (3) As gases in plasma state, Ar, CCl_4,
2. The method for producing a master of a flat information recording carrier according to claim 1, characterized in that at least one of CH_2Cl_2, BCl_3, and O_2 is used.