JP3187067B2 - Optical disc manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing an optical disc.

[0002]

2. Description of the Related Art As a method for manufacturing an optical disk, for example, a video disk, a method as shown in FIG. 2 is conventionally known. According to this manufacturing method, first, as shown in FIG. 2A, the photoresist layer 2 is uniformly formed on the main surface of the glass disk 1.
Is prepared, and a latent image of a spot row corresponding to predetermined information is spirally or concentrically formed on the photoresist layer 2 by irradiating a blinking laser beam La in accordance with a predetermined signal. I do. Next, the exposed photoresist master is developed to provide a row of minute recesses (hereinafter referred to as pits) corresponding to signals to be recorded on the photoresist master, and has a pit as shown in FIG. A development master comprising a photoresist layer 2 (information recording layer) and a glass disk 1 is obtained. Next, the photoresist layer 2 of the development master is dried and fixed (post-baked) on the glass disk 1 to obtain a dried master as shown in FIG. Next, a metal film such as silver or nickel is sputtered to form a conductive film 3 on the photoresist layer 2 to obtain a laminated mastering master 3a as shown in FIG. 2D. Thus, the information recording surface having pits is made conductive by sputtering metal on the photoresist layer having pits. Next, the obtained mastering master is immersed in a nickel electroforming bath, and nickel (Ni) is plated (electroformed) on the conductive film 3 to form a thick nickel layer 4, that is, a nickel stamper. A disk as shown in (e) is obtained. Next, the stamper as the nickel layer 4 is separated from the glass disk 1 as shown in FIG. Next, the photoresist layer 2 and the conductive film 3 remaining on the stamper are removed to obtain a nickel stamper shown in FIG.

[0003] Thereafter, a nickel stamper is attached to a predetermined position of an injection molding apparatus, and after clamping, a transparent resin material such as molten fluid PMMA (polymethyl methacrylate) and PC (polycarbonate) is injected onto the nickel stamper. After the resin material is cured, the resin material is taken out and an optical disk replica having a predetermined information recording surface is created. The replica thus obtained is formed by forming a reflective film such as aluminum on the information recording surface of the replica by a known method, and further overcoating the protective film on the reflective film to form an optical disc. . In addition, a two-sided optical disk is usually obtained after two optical disks are pasted and subjected to a finishing process.

However, in such a conventional method, the number of steps of the electroforming process is large until the stamper is manufactured, and it takes a long time for plating. Further, an injection molding apparatus for manufacturing a replica requires a relatively large apparatus. is there. Since it takes time and cost to manufacture a stamper, it cannot be said that it is adequately suitable for manufacturing several optical discs corresponding to various kinds of video and audio software in recent years.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing an optical disk suitable for a large number of products in a small number and in a large scale by relatively simple steps.

[0006]

The method of manufacturing an optical disk according to the present invention is directed to irradiating a master disk comprising a transparent substrate and a photoresist layer containing a resin, a photosensitive agent and a ballast compound formed on the transparent substrate with a focused laser beam. Exposing the photoresist, developing the master to form fine irregularities on the surface of the photoresist layer, heating the photoresist layer and fixing the post-baking, the surface of the master And a transfer step of forming a transfer layer made of a transparent ultraviolet curable resin on the surface of the photoresist layer.

[0007]

According to the present invention, the stamper manufacturing time can be reduced and the optical disk manufacturing method can be simplified.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In manufacturing one or several optical discs of the present embodiment, the pattern of the pits in the minute concave row, which is the information recording surface of the mastering master, is transferred by a resin stamper instead of a metal stamper, and a replica is manufactured from the resin stamper. A method is conceivable. According to this method, a fluid of a photopolymer (referred to as 2P), which is an ultraviolet-curable resin, is supplied and applied onto the information recording surface, and then irradiated with ultraviolet rays to cure the 2P as a transfer layer 40 on the information recording surface. This is a 2P method. When a replica is produced by transferring by the 2P method, it is necessary to form a barrier layer such as a metal film on the surface of the photoresist layer on the mastering master in order to prevent the photoresist from being eroded by the 2P agent. There were problems (1) to (3), which were solved.

(1) It takes time and effort to form a metal film. (2) Since the barrier layer is provided on the pit formed by the photoresist layer, the shape of the pit on the transfer surface changes, and the reproduction signal from the replica optical disk obtained from the resin stamper deteriorates. (3) Since the mastering master is taken out of the clean atmosphere and put into the vapor deposition machine, there is a possibility that dusts that cause dropout may adhere.

In order to solve these problems, the inventor has developed a manufacturing method as shown in the following embodiments. First, a photoresist master 20 is prepared by uniformly forming a photoresist layer 20 by spin coating or the like over the main surface of a cleaned transparent disk 10 made of glass as a substrate for a mastering master. As shown in FIG. 1A, a latent image of a spot row corresponding to predetermined information is spirally or concentrically formed on the photoresist layer 20 by irradiating a blinking laser beam La in accordance with a predetermined signal to be recorded. Formed. The photoresist layer 20 is composed of a resin, a photosensitive agent, and a ballast compound, and the components will be described later in detail.

Next, the exposed photoresist master is developed to provide a row of minute concave portions corresponding to signals to be recorded on the master, and a photoresist layer 20 having pits as shown in FIG. (Development master) comprising (information recording layer) and transparent substrate 10 is obtained. Next, the photoresist layer 20 of the development master is heated and dried and fixed (post-baked) on the transparent substrate 10 to obtain a master as shown in FIG. 1 (c).

Next, as shown in FIG. 1D, ultraviolet rays are irradiated from above the photoresist layer 20 to promote crosslinking of the resin and the like in the photoresist layer 20, and the photoresist layer is cured as an information recording surface. Obtain a mastering master. Next, as shown in FIG. 1 (e), a 2P fluid, which is an ultraviolet curable resin, is supplied and applied onto the information recording surface of the minute concave row, and thereafter, the 2P is recorded by irradiating ultraviolet rays. It is cured as the transfer layer 40 on the surface. This transfer layer 40
Alternatively, a stamper holding substrate (not shown) may be provided on the upper surface of the drawing so as to be carried on a suitable stamper holding substrate, and the transfer layer 40 may be formed between the development master and the stamper holding substrate.

Next, as shown in FIG.
0 is peeled off from the development master. This transfer layer 40 is formed as a resin stamper. In the optical disk manufacturing method according to the present embodiment, the steps up to the post-baking step are the same as those in the related art. The present embodiment is characterized in that a crosslinking promoting step of the photoresist layer 20 is provided after the post-baking step.

[0014] That is, in fabricating a single to several optical disks of the present embodiment, to improve the resistance to 2P agent by proceeding the crosslinking of the photoresist layer, to 2P transfer without the barrier layer on the photoresist surface That was realized. The photoresist layer preferably has the following components (1) to (3). (1) Resin component (base polymer): The resin is preferably mainly cresol novolak represented by the following chemical formula 1.

[0015]

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(2) Photosensitizer: The photosensitizer is preferably 1,2naphthoquinonediazide-5-sulfonic chloride represented by the following chemical formula 2, and ballast compounds and esters represented by the following chemical formulas 3 to 15.

[0017]

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(3) Ballast compound: The ballast compound is preferably represented by the following chemical formulas 3 to 15, and the compounding amount is 3 to 9 wt. % Is preferred.

[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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The photoreaction of the photosensitizer of the photoresist such as naphthoquinone azide as shown in the above chemical formula 2 by the ultraviolet light hν proceeds as shown in the following chemical formula 16.

[0033]

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Here, from the viewpoint of the progress of crosslinking, when heat (baking) or light (ultraviolet light) is applied to indene ketene that is easily cross-linked in the absence of water, the base polymer is cross-linked by the indene ketene, which is efficient It is. In particular, in the case of cresol novolac, which is the main component of the base polymer of the current positive photoresist, a stable thermosetting bakelite (cresol formalin resin) is finally obtained by promoting crosslinking. Ballast compound, its -OH group by adding a photosensitive agent can introduce a large amount of photosensitive agent in the resist, it is possible to increase the degree of crosslinking of the base polymer.

[0035]

As described above, according to the optical disk manufacturing method of the present invention, it is possible to simplify the manufacturing process while achieving accurate transfer of the information recording surface in the optical disk manufacturing process, and to realize a small amount of various kinds of video / audio software. Suitable for the production of corresponding small quantity optical discs.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a member in each step of a method for manufacturing an optical disk according to the present invention.

FIG. 2 is a schematic sectional view of a member in each step of a conventional optical disc manufacturing method.

[Explanation of symbols]

 10 Transparent substrate 20 Photoresist layer 40 Transfer layer

Continued on the front page (72) Kunizo Ogoshi, Inventor 6-11 1-1, Fujimi, Tsurugashima-cho, Iruma-gun, Saitama Prefecture (72) Inventor Shin-ichi Yokoseki 6-1-1, Fujimi, Tsuruga-machi, Iruma-gun, Saitama No. 1 Inside Pioneer Corporation Research Laboratory (56) References JP-A-57-6546 (JP, A) JP-A-63-113832 (JP, A) JP-A-63-197611 (JP, A) JP-A-3 -194742 (JP, A) JP-A-63-215040 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 7/26 G11B 11/105

Claims (1)

(57) [Claims] 1. A step of exposing a photoresist by irradiating a master laser comprising a transparent substrate and a photoresist layer formed on the transparent substrate and containing a resin, a photosensitive agent and a ballast compound with a focused laser beam. A developing step of developing the master to form fine irregularities on the surface of the photoresist layer; a post-baking step of heating and fixing the photoresist layer; and an ultraviolet irradiation step of irradiating the surface of the master with ultraviolet light And a transfer step of forming a transfer layer made of a transparent ultraviolet curable resin on the surface of the photoresist layer.