Stamper for high-density recording disk and production thereof

[Detailed Description of the Invention]

[0001]

[Industrial Application]

The present invention relates to La Stampa for fabrication of a high-density-recording disk, and a manufacturing method for the same.

[0002]

[Description of the Prior Art]

The progress in the recent years of an information storage disk has a remarkable thing, for example, the rise of a narrow track pitch or linear recording density is considered also in the field of an optical disc. For example, the music playback disk and the playback disk of the compression picture can be considered as a next-generation type of a compact disk (CD) for a long time, and the report relevant to it is introduced to the newspaper.

[0003]

As for such a high-density-recording disk, since the size of a pit becomes small [ length and width ] inevitably, the precise pit transfer from La Stampa becomes difficult. nickel is a soft metal as everyone knows, and La Stampa is hard to be referred to as not necessarily suitable for such precision transfer, although what was conventionally made from nickel has been used. It cannot be said that smoothness is also good.

[0004]

[Problem(s) to be Solved by the Invention]

By the way, there is glass as a material which was strong and excelled metal in smoothness, and if La Stampa is made by this, it can use for fabrication of a high-density-recording disk enough. If a bad material of thermal conductivity like glass is used as a material of La Stampa, as shown in Japanese-Patent-Application-No. No. 256105 [ one to ] specification for which these people applied previously, the double reflex of a disk can be reduced in injection molding process, and it is still more effective.

[0005]

That outline is as follows although these people have applied as Japanese Patent Application No. No. 14085 [ 63 to ] previously about this glass La Stampa including that manufacturing method. Drawing 4 shows the manufacturing process of conventional forming La Stampa of this kind of high-density-recording disk. First, photoresist 2 of Negative type is uniformly applied on the surface of silica glass board 1 ground with high density (Drawing 4 (a)). Next, a desired pattern is continuously recorded [ use laser beam 3 and ] a guide rail and (Drawing 4 (b)) obtained by a processing procedure on this photoresist 2 (Drawing 4 (c)). Next, it is CF4 to this substrate. Dry etching is performed in gas plasma 4, and it is made to stop in the desired depth (Drawing 4 (d)). Ashing of the photoresist 2 which remains is carried out by oxygen (O2) plasma, it is removed, and glass La Stampa is obtained (Drawing 4 (e)). The disc substrate was created by the 2P method etc. from this La Stampa, and record film and a protective film were coated, for example, information storage carriers, such as an optical disc, had been obtained. With the photo lithography using the photoresist (it may only be hereafter described as negative resist.) of Negative type at this time, In dry etching, glass La Stampa in which the pit width of La Stampa is [ even 1.00 micrometers ] a limit, namely, it is a limit and even a little bigger pit size than CD has a pit of the following width was not able to be created. This is for the foot of a pit to spread widely according to the feature said that character peculiar to negative resist, i.e., the solubility ratio of an exposure part and an unexposed part, is small, even if it makes irradiation light into short wavelength.

[0006]

[Means for Solving the Problem]

What the present invention provides with a manufacturing method of La Stampa for high-density-recording disks, respectively, It is made in order to solve the above-mentioned conventional subject characterized by comprising the following, and it is as the 1st invention, Forming La Stampa of a high-density-recording disk which creates an information carrier which has the information pattern by making a resin material counter the La Stampa surface which has a reversal pattern of an information signal pattern, and making it harden. A process of applying a positive-resist film which induces irradiation of a beam on a glass board flat as the 2nd invention again in La Stampa for high-density-recording disks which it is a range whose width of the minimum pit is 0.15 micrometer ~ 1.00 micrometers, and the quality of the material becomes from glass, A process of irradiating with the beam modulated by the positive-resist film according to an information signal pattern, A process which carries out reverse bake, The positive-resist film is developed [ a process of carrying out package exposure of the whole surface containing the portion by which reverse bake was carried out, and ], A process of removing the resist film of a portion which is not irradiated with the beam, and forming the resist film of a pattern according to the information signal pattern, a process of etching the glass board to the predetermined depth by using the resist pattern as a mask, and a process of removing the positive-resist film.

[0007]

[Example]

In order to solve the above problems, the photosensitive materials which can take a large solubility ratio are used for the present invention. Although the photoresist (it may only be hereafter described as a positive resist) of general Positive type corresponds to this, it is unsuitable for obtaining a convex pattern (pattern of La Stampa) with high precision. Although it becomes the package exposure which passed the mask inevitably in this case, under the present circumstances, it is also difficult to create such a highly precise mask. Then, although it was possible that the image reversal method which can form a convex pattern is suitable, using a positive resist, resolving of 0.6-micrometer width was formerly a limit also about this. However, when examination is wholeheartedly advanced about this technique, the pattern below 0.6 mum is also possible enough, and optimization of a process shows that it can do to 0.15-micrometer resolving.

[0008]

It is required to use a short wavelength laser beam for exposure, and to specifically condense a spot to near the 0.5 mum first. The example of It was done is shown for image reversal as Drawing 2 under this condition (laser wavelength as conditions : 413 nm, NA:0.94, and resist:AZ5206E). This Drawing 2 makes reverse baking temperature and laser power a parameter, and investigates the width of a pit. Thus, it turns out that it is in the tendency which becomes thick as reverse baking temperature becomes high, a pit becomes thick and laser power becomes strong. In other words, pattern Ning of desired pit size can be carried out by making at least 1 side of reverse baking temperature and laser power change. The width of the shortest pit convex shape acquired at this time was 0.15 micrometer at the minimum.

[0009]

Example 1 Drawing 1 is a figure showing an example of the manufacturing process of La Stampa for high-density-recording disks which becomes the present invention. First, photoresist 11 (AZ5206E resist and Hoechst Japan, Inc.) of Positive type was uniformly applied by a thickness of 1000 A on the surface of silica glass board 10 ground with high density, and this was prebaked by 90 degreeC for 30 minutes (Drawing 1 (a)). Next, on this positive resist 11, Kr laser of 413 nm and the lens of NA0.94 were used, and the guide rail was recorded using laser beam 12 of laser power 4.6 mW (Drawing 1 (b)). Next, the baking powder (reverse bake) of this is carried out for 5 minutes by 115 °C, and exposure part 13 is made to crosslink (Drawing 1 (c)). next, portion 11A into which package exposure of the whole surface was carried out, and laser exposure was not performed -- alkali -- suppose that it is meltable (Drawing 1 (d)). Then, a convex pattern is obtained by developing negatives for 30 seconds (Drawing 1 (e)). This is made into a mask and it is 6.0x10-2. Dry etching is carried out on condition of torr (gas is CHF3) and 200 W (Drawing 1 (f)). Then, extant photoresist is removed and desired La Stampa is obtained (Drawing 1 (g)). It is height 850 when Tarrystep and SEM estimated obtained La Stampa. Glass La Stampa which has a convex pit of angstrom and pit width 0.3 mum was obtained.

[0010]

Example 2 Laser power was set to 2.4 mW, and also it presupposed that it is the same, and created glass La Stampa. It is height 850 when the same means estimated. Glass La Stampa which has a convex pit angstrom, and [ pit / 0.15 micrometer ] in width was obtained.

[0011]

As mentioned above, a positive-resist film is used and glass La Stampa which has a convex pattern below impossible 0.6 mum can be conventionally created by using the image reversal method. The width of a pit can obtain desired La Stampa by changing at least 1 side of the power of cutting, and baking powder temperature.

[0012]

Hereinafter, the point is explained, using Drawing 3 as an example which performed comparison on a disk using La Stampa. Since many pits can be arranged in the direction of a track if pit width is made small so that more clearly than this Drawing 3, it becomes possible to narrow a track pitch. It turns out that it becomes possible to make it one 16 times the capacity of this at 0.15 micrometer of the CD 4 times the capacity of the present, and a half by 0.3 mum of a pit width half.

[0013]

In the above-mentioned example, although recorded by condensing laser, this may be performed using the method of carrying out package exposure via the same mask as a semiconductor process. In that case, two photo lithography processes, pattern Ning of a mask and pattern Ning of glass, are needed. However, since much La Stampa can be created by repetition of package exposure once it produces a mask, it is a technique suitable for production. Here, either pattern Ning of a mask and pattern Ning of glass serve as the image reversal method and the photolithographic method by a photoresist usual in another side.

[Effect of the Invention]

A resin material is made to counter the La Stampa surface which has a reversal pattern of an information signal pattern, as the present invention was explained in full detail above. In forming La Stampa of a high-density-recording disk which creates an information carrier which has the information pattern, it is a range whose width of the minimum pit is 0.15 micrometer ~ 1.00 micrometers by making it harden. Since the quality of the material constituted La Stampa for high-density-recording disks which consists of glass, glass La Stampa which recorded information with high density can be provided. And since this La Stampa is strong and excellent in smoothness, it can be used for fabrication of a high-density optical disc.

[Brief Description of the Drawings]

[Drawing 1]

It is a figure showing an example of the manufacturing process of La Stampa for high-density-recording disks which becomes the present invention.

[Drawing 2]

It is a figure showing the relation of the cutting power and the pit depth in the manufacturing process of La Stampa for high-density-recording disks which becomes the present invention.

[Drawing 3]

It is a figure showing an example which performed comparison on a disk using La Stampa for high-density-recording disks which becomes the present invention, and other La Stampa.

[Drawing 4]

It is a figure for explaining an example of the manufacturing process of conventional La Stampa.

[Description of Notations]

10 Glass Substrate 11 Positive Resist 12 Laser Beam 13 Exposure Part