JP2715863B2 - Manufacturing method of stamper for manufacturing optical disc - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing an optical disk producing static <br/> down path, in particular, it relates to a manufacturing method of a preferred optical disk producing Stan path when increasing the density of the track pitch .

[0002]

2. Description of the Related Art Conventionally, in a mastering process of an optical disk medium having a normal spiral continuous groove or an optical disk master having a concentric groove, a positive photoresist is applied to a smooth disk-shaped glass plate. A spiral or concentric groove pattern is formed on the optical disk master by exposing the optical disk master in a spiral or concentric manner with the focused laser beam, and developing and removing the photoresist on the exposed portion. Next, after forming a metal layer by electroforming the pattern forming surface, the metal layer is peeled off from the master optical disc, so that the metal layer is used as a metal mask or stamper of the optical disc medium, and the pattern is formed by resin molding using the stamper. Is transferred to resin to manufacture optical discs.

By the way, the width of a groove formed on an optical disk depends on the diameter of a condensed beam of a laser used.
In the mastering step of the high-density optical disc master, as a first method, as described in, for example, JP-A-3-108141, the developed optical disc master is etched from the resist layer side, and the glass plate is etched on the resist layer. There is a method of transferring an exposure pattern. Since the groove pattern on the resist layer formed on the master has a tapered shape in which the cross section has a wide surface side and a narrow glass substrate side, when the glass plate is etched from the resist layer side, the groove pattern is formed on the resist layer. As a result that a pattern narrower than the exposure pattern is formed on the glass plate, it is possible to form a groove pattern narrower than normal optical disc mastering.

Further, as a second method, for example,
As described in JP-A-3111833, a method of forming a narrow groove pattern by condensing a laser beam using a super-resolution phenomenon and reducing a beam spot diameter formed on an optical disk master. There is.

Further, as a third method, for example,
There is a method of forming a narrow groove pattern by reducing a focused spot using an electron beam described in JP-A-335228 or UV having a shorter wavelength than visible light used in ordinary optical disc mastering. .

Further, as a fourth method, as described in, for example, Japanese Patent Application Laid-Open No. 4-372740, a contrast enhancer is further applied on the optical disk master to transmit only the central portion of the beam spot where the light intensity is strong. With such a structure, there is a method of forming a groove pattern having a width smaller than the beam spot diameter.

[0007]

However, in the above-mentioned prior art, the width of the groove pattern formed on the optical disk master has the property of being dependent on the diameter of the focused laser beam used. Although it is possible to form a groove pattern slightly smaller than the beam diameter, there is a problem that it is impossible to form a groove pattern having a sufficiently narrow width. In addition, when a short-wavelength light source or an electron beam is used to form a groove pattern on an optical disk master, it is necessary to significantly modify an existing exposure apparatus. However, there is a problem that the cost required for the remodeling becomes enormous.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art and, in particular, to provide an optical disk manufacturing stand capable of manufacturing an optical disk having a high track pitch.
It is an object of the present invention to provide a method for manufacturing a package .

[0009]

[Means for Solving the Problems]

In the method of manufacturing a stamper for manufacturing an optical disk according to the present invention, a coating step of coating a photoresist film on an upper surface of a glass substrate and a pitch between centers of exposed portions when the photoresist film is exposed to a laser beam are defined by an exposure width. An exposure step of forming a plurality of exposed portions at equal intervals by setting less than twice, and a developing step of developing the photoresist film to remove the exposed portions and form a plurality of patterns on the glass substrate; A first electroforming step of forming a metal layer by electroforming on the pattern forming side of the glass substrate, and a mother manufacturing step of peeling the metal layer having the pattern transferred from the glass substrate and using the metal layer as a mother And a second electroforming step of forming a metal layer by performing electroforming on the pattern forming side of the mother;
And a stamper manufacturing step of removing the metal layer on which the pattern is transferred from the mother and using the metal layer as a stamper. This aims to achieve the above-mentioned object.

[0011]

[Action]

According to the method of manufacturing a stamper for manufacturing an optical disk of the present invention, the pitch between the centers of the exposed portions is set to be less than twice the exposure width at the time of exposing the photoresist film by the laser beam in the exposing step. Are formed at equal intervals, the pitch between the centers of the patterns in the stamper manufactured in the stamper manufacturing process can be less than twice the width of the pattern. As a result, for example, the If the pattern is transferred to the resin by performing resin molding using the stamper formed in the above, without modifying the exposure device, a high-density groove having a groove narrower than the land width corresponding to the exposure width by the laser beam An optical disc can be manufactured.

[0013]

BRIEF DESCRIPTION based on an embodiment <br/> formed by applying the manufacturing method of the optical disk producing Stan path of the present invention with reference to the accompanying drawings.

The method of manufacturing an optical disk in this embodiment is as follows.
When a plurality of exposed portions 5A, 5B, 5C,... Corresponding to grooves are formed in the positive photoresist film 2 of the optical disk master 3 in a wide groove exposure process described later, the pitch between each exposed portion (track pitch) ) Is set to be less than twice the exposure width by the condensed beam, so that the groove pattern narrower than the exposure width by the condensed laser beam can be formed on the optical disk without modifying the exposure apparatus. Thus, a high-density optical disk can be manufactured.

The optical disk manufacturing method of this embodiment will be described with reference to FIG. 1. The optical disk manufacturing process includes a photoresist coating process, a wide groove exposure process, a developing process, a first electroforming process, The configuration includes a manufacturing process, a second electroforming process, a stamper manufacturing process, a resin molding process, and an optical disc manufacturing process.

The optical disk manufacturing process will be described in detail.
First, in a photoresist coating step, an optical disc master 3 is manufactured by applying a positive photoresist film 2 to the upper surface of a glass substrate 1 (see FIG. 1A).

Next, in the wide groove exposure step,
A lens 4 is arranged above the positive photoresist film 2 of the optical disk master 3 shown in FIG.
A laser beam emitted from the lens 4 is condensed by a lens 4 and the condensed beam is irradiated on the positive photoresist film 2 to thereby expose the positive photoresist film 2 to a plurality of exposure portions 5A, 5B, 5C corresponding to grooves. Are formed at a predetermined width and at regular intervals. Thereby, the exposure units 5A, 5B, 5
The optical disc master 6 having C... Is manufactured.
(B)).

In this case, the pitch between the centers of the exposed portions, that is, the track pitch is set to be less than twice the exposure width of the condensed beam. This is the optimal pitch obtained by experiments by the applicant. This makes it possible to manufacture an optical disk having a groove having a width smaller than the width of the land corresponding to the exposure width by the condensed beam, in other words, having a high-density continuous groove, without modifying the exposure apparatus. It has become.

Next, in the developing step, the exposed portions 5A, 5B, 5C,... Of the optical disk master 6 shown in FIG.
Are subjected to a development process to remove the exposed portions 5A, 5B, 5C,..., So that patterns 6A, 6B corresponding to grooves are formed on the upper surface of the glass substrate 1. , 6C,. Thus, an optical disk master 7 having the patterns 6A, 6B, 6C,... Is manufactured (see FIG. 1C).

Next, in the first electroforming step, FIG.
(C) The upper surface side of the positive photoresist film 2 on the optical disk master 7 (the patterns 6A, 6B,
The metal layer 8 is formed on the upper surface of the positive photoresist film 2 by performing electroforming on 6C... Thus, an optical disk master 9 having the metal layer 8 is manufactured (see FIG. 1D).

Next, in the mother manufacturing process, FIG.
When the metal layer 8 is peeled off from the optical disk master 9 of (d),
The patterns 6A, 6B, 6C,... Are transferred to the metal layer 8, and a mother 10 is manufactured (see FIG. 1E).

Next, in the second electroforming step, FIG.
(E) Patterns 6A, 6B, 6C in mother 10
The metal layer 11 is formed on the upper surface of the mother 10 by performing electroforming on the forming side. Thereby, the mother 12 having the metal layer 11 is manufactured (FIG. 1F).
reference).

Next, in the stamper manufacturing process, FIG.
When the metal layer 11 is peeled off from the mother 12 of (f), the patterns 6A, 6B, 6C,.
The stamper 13 is manufactured (see FIG. 1 (g)).

Next, in the resin molding step, FIG.
By performing resin molding using the stamper 13 of (g) and transferring the patterns 6A, 6B, 6C... To the resin 14, an optical disk master 15 having the resin 14 molded on the lower surface of the stamper 13 is manufactured. (See FIG. 1 (h)).

Finally, in the optical disk manufacturing process,
When the stamper 13 is separated from the master optical disk 15 shown in FIG. 1H, an optical disk 16 is manufactured (see FIG. 1I). The above is the manufacturing process of the optical disk.

FIG. 2 is a view showing a part of a cross section of the optical disk 16 manufactured by the above-described manufacturing process. A plurality of lands 17A, 17B,
17C and the grooves 18A, 18B, 18C... Are alternately formed. In this case, the land 17A,
.. Correspond to the exposure width by the condensed beam used in the wide groove exposure process of FIG. 1B, and the width of the grooves 18A, 18B, 18C.
7A, 17B, 17C,... In the figure, reference numeral 19 denotes a transparent protective film for protecting the surface of the optical disk 16.

As described above, according to the present embodiment, after the photoresist coating step, the wide groove exposure step of performing the exposure by setting the pitch between the centers of the exposed portions to less than twice the exposure width by the condensed beam. And then the development step, the first
In order to manufacture an optical disc through the electroforming step, the mother making step, the second electroforming step, the stamper making step, the resin forming step, and the optical disc making step, without modifying the exposure apparatus, as shown in FIG. It is possible to manufacture an optical disc 16 having a high-density continuous groove having a groove 18 having a width smaller than the width of the land 17 corresponding to the exposure width by the condensed beam.

In this case, in this embodiment, the optical disk having the shape shown in FIG. 1 (i) was manufactured by two electroforming steps, but the stamper having the shape shown in FIG. 1 (g) is further electroformed. If a stamper having the inverted shape of the stamper is manufactured in this way, it is possible to manufacture an optical disc having the inverted shape of the optical disc shown in FIG.

[0029]

【The invention's effect】

As described above , according to the method of manufacturing a stamper for manufacturing an optical disk of the present invention, the pitch between the centers of the exposed portions is set to less than twice the exposure width when the photoresist film is exposed to the laser beam in the exposure step. Then, the plurality of exposed portions are formed at equal intervals, so that the pitch between the centers of the patterns in the stamper manufactured in the stamper manufacturing process can be less than twice the width of the pattern. As a result, for example, If the pattern is transferred to the resin by performing resin molding using a stamper with the pattern formed in a concave shape at the pitch, without modifying the exposure device, the width of the land smaller than the width of the land corresponding to the exposure width by laser light It is possible to manufacture a high-density optical disk having grooves,
The effect described above can be achieved.

[Brief description of the drawings]

FIGS. 1A and 1B show each step of manufacturing an optical disc according to an embodiment of the present invention. FIG. 1A shows a photoresist coating step, FIG. 1B shows a wide groove exposure step, and FIG. ) Is a development step, FIG. 1D is a first electroforming step, FIG. 1E is a mother manufacturing step, FIG. 1F is a second electroforming step, and FIG. 1 (h) is an explanatory view showing a resin molding step, and FIG. 1 (i) is an explanatory view showing an optical disk manufacturing step.

FIG. 2 is an explanatory diagram showing a part of a cross section of the optical disc in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Positive photoresist film as a photoresist film 5A, 5B, 5C Exposure part 6A, 6B, 6C Pattern 8, 11 Metal layer 10 Mother 13 Stamper 16 Optical disk 17 Land 18 Groove

Claims (1)

(57) [Claims] 1. A photoresist film is formed on an upper surface of a glass substrate.
A coating step of coating and the photoresist by laser light
When exposing the film, the pitch between the centers of the exposed parts
Dew to form a plurality of exposed parts at equal intervals by setting it to less than twice
A light process, developing the photoresist film and exposing each light
Removing portions to form a plurality of patterns on the glass substrate
Developing step, electroforming on the pattern forming side of the glass substrate
Performing a first electroforming step of forming a metal layer;
Peel the metal layer with the pattern transferred from the plate
A mother preparation process using the layer as a mother, and a pattern of the mother
Electroforming for forming a metal layer by performing electroforming on the forming side
And removing the metal layer on which the pattern has been transferred from the mother.
Forming a stamper using the metal layer as a stamper apart from the stamper;
Optical disc manufacturing star characterized by comprising:
Manufacturing method of damper.