JPS60182030A - Substrate for information recording and its production - Google Patents

Abstract

PURPOSE:To form easily a memory disk having high uniformity by forming directly ruggedness on a glass substrate subjected to low temp. type ion exchange treatment thereby eliminating the need for a resin layer. CONSTITUTION:A discoid soda lime glass substrate 1 is subjected to low temp. type ion exchange treatment and is thereby chemically reinforced. The substrate is thereafter subjected to silazane treatment to increase the adhesive force to resist and photoresist is coated on one main surface of the substrate 1 and is prebaked. The photoresist is exposed by using a photomask on a disk patterned with the signals for pregrooves and is further developed, dried and post baked to form a resist pattern 4. The substrate is subjected to sputter etching by using a palallel flat plate type plasma etching device using the resist pattern as a mask, by which grooves 5 are obtd. The resist is stripped by hot concd. sulfuric acid, etc. and the substrate is washed and dried. A substrate 6 for information recording is thus formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an information recording substrate used for optical disks, magneto-optical disks, etc., and a method for manufacturing the same.

[“Prior Art”] Conventionally, this type of memory disk has been formed, for example, in the following manner: First, the entire surface of a glass master disk is coated directly with chromium or by a thin coating of chromium to strengthen the adhesion of the resist. Then, a desired resist pattern is formed by cutting using a laser beam, and in order to make it conductive, silver is deposited by a silver mirror reaction or a metal film (e.g., gold,
[Silver, nickel] After full coating, nickel is further plated. This is peeled off from the all-glass master disc to create a nickel master disc. Next, the very surface layer of this master disk is oxidized with dichromium, plated with nickel again, and this area is peeled off from the master disk. Create a standby in the same manner as described above for the mother disk.

The back surface of the stamper is polished, and using this stamper, a resin is placed between the glass disk and the stamper, and the resin is cured by heat or UV light, such as UV light, to transfer the irregularities of the stamper. The information recording substrate obtained in this manner is shown in FIG. In the figure, there is one tri soda lime glass substrate and two resin layers. Various recording thin films and a protective layer are formed on the uneven surface of the resin N2 of this information recording substrate, and furthermore, in the case of a 30-disk etc., two such discs'fC information recording layer is placed on the inner side. A memory disk is formed by pasting them together. . In addition, the unevenness is
However, in this 11-, conventional memory disk, the resin layer initial It must be formed uniformly, especially the effects of bale refraction, etc., and optically (C) it must be formed uniformly, and furthermore, it must be formed uniformly to avoid defects such as severance. The 1-inch resin layer is transferred to the resin layer (it is necessary to make a complete stambar with no defects), and the fine guide grooves on the stambar must be accurately transferred. There are four difficulties in manufacturing.

[Summary of the Invention] The present invention (CI) was made in view of the above circumstances, and its purpose is to provide an information recording substrate that can easily form a highly uniform memory disk and a method for manufacturing the same. It is about providing.

In order to achieve such an object, the information recording substrate according to the present invention is a FC glass substrate subjected to low-temperature ion exchange treatment to form j-bar contact unevenness, thereby eliminating the need for a resin layer.

Further, in order to obtain such an information recording substrate, the method for manufacturing an information recording substrate according to the present invention involves forming "C unevenness" using a sputter etching method.

Here, low-temperature ion exchange treatment is a type of glass strengthening method, and is performed at a temperature below the glass transition point, for example, at a temperature of 380 to 450 °C for soda lime glass.
Alka ions in glass (Na+ ions in this example)
I decided to replace it with an alkali ion (thicker than this) with a radius of 2 ions (with a radius of 10,000 ions).
= This is a method of introducing compressive stress to the surface of the metal. In addition,
The Na+ ions on the glass surface are not replaced by 2 degrees, and the replacement rate is about 90%. -Furthermore, the molten salt used in this ion exchange treatment is mainly composed of nitrates, but sulfates can also be used. This not only mechanically strengthens the glass substrate, but also reduces the concentration of sodium ions on the surface, improving etching re-IJI properties and suppressing deterioration of the recording medium.

Since sputter etching has a directionality of -1-7, the undercut is small, and it is possible to perform it under etching conditions with good re-patterning due to unevenness in the depth direction. Hereinafter, the present invention will be explained in detail using a major example.

[Embodiment] FIGS. 2(a) to 2(d) are process sectional views showing an embodiment of the present invention.

Masu, outer diameter 20Urr, +n, inner diameter 35mm, plate thickness 1
A 62 mm tissue-shaped soda lime glass substrate 1 is immersed in molten potassium nitrate at 380 to 450° C. for several tens of minutes to several tens of hours to undergo low-temperature ion exchange treatment and to chemically strengthen it. Thereafter, a silazane treatment was applied to strengthen the adhesion with the resist, and then a 7-photoresist Az1300-27 (US Hoec
About 20,000λ of Co., Ltd.) 3 was applied and prebaked (Fig. 2(a)).

Next, exposure is performed using a 7-otomask on a disc patterned with pregroove signals, and this is further developed, dried, and post-baked to form a resist pattern 4 (FIG. 2(b)).

Next, using this 1/cyst pattern as a whole mask, using a parallel plate plasma etching apparatus, Ar gas pressure was set at 5
x 10 Torr, high frequency output 200W (0,44/
Sputter etching was carried out under etching conditions of cm2). If the wavelength of the laser beam used for recording and reproduction is λ, the etching depth is approximately λ/4 or λ/
It is necessary to set it to 8, but in this example it is 1200 to 1300.
I gave it an A. As described above, by using sputter etching, grooves 5 with small undercuts, good reproducibility, and almost no variation in the depth direction can be obtained (FIG. 2(C)).

Thereafter, the resist is peeled off using an organic solvent such as acetone, hot concentrated sulfuric acid, etc., followed by cleaning and drying to produce the information recording substrate 6 (FIG. 2(d)).

After that, the substrate 6 of C was formed with unevenness, and 14 memory thin films and protective layers were formed on the king surface 7j.
rFurthermore, the two disks formed by this twisting are
By sealing the memory card so that the recording layer is on the inside, the memory card becomes durable.

In addition, during the above process, before applying the photoresist, the chemically strengthened glass substrate 1e was subjected to silazane treatment.
5tO2, which is the main component of glass, creates Vζ silanol groups on the glass surface with moisture in the air and weakens the adhesion to the resist. It is also possible.

In addition, as an etching gas for sputter etching,
Not only Ar but also a mixed gas of Ar and fluorine such as CF4 may be used. In that case, 1d: the surface layer of the glass is chemically etched due to the active species generated by the decomposition of CF4, which has the advantage that the etching time can be shortened.

Furthermore, although a disk-shaped photomask was used as an exposure method for photoresist, this is not limited to a disk-shaped photomask.
You can also use it as a square shape. In addition, without using a photomask, the entire resist was exposed directly to the laser beam, making it possible to create butter-22/
You can also search.

Note that birefringence occurs when the glass substrate is subjected to low-temperature ion father exchange treatment, but this does not pose a problem because the refractive index is uniform and the direction of birefringence is the same.

〔Effect of the invention〕

As explained above, according to the present invention, a glass substrate subjected to low-temperature ion exchange treatment is used, and by performing TC to form smooth irregularities in the contact system on this glass substrate,
Since there is no need to make a stamper and mold the resin, the process can be simplified and compared to resin.
A product with high strength can be obtained. In particular, the use of glass substrates that have been chemically strengthened through low-temperature ion-exchange treatment makes them difficult to break, and the sodium ion concentration on the glass surface is extremely low, making it possible to achieve highly uniform etsonization with good reproducibility, as well as to improve recording performance. Deterioration of the medium due to sodium ions can also be prevented. Since soda lime glass, which is relatively inexpensive, can be used as the substrate, it is effective in reducing manufacturing costs.

In addition, the desired unevenness can be easily processed by using sputter etching.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional information recording substrate, and Figure 2 (
a) to (d) are cross-sectional views of one culm showing one embodiment of the present invention. 1...t soda lime crow base, 3...fu 1st
・Resist, 4...Resist pattern, 5...
Naturally, 6... information recording board. Bamboo permit applicant Hoya Glass Co., Ltd. Agent Masaki Yamakawa (and 2 others) Figure 1 Figure 2

Claims (2)

[Claims] (1) In a 1# information recording substrate consisting of a disk-shaped substrate with unevenness on the main surface on the side to which the entire recording medium is attached, the disk-shaped substrate is made of a glass substrate subjected to low-temperature ion exchange treatment. Information recording board with characteristics. (2) The step of applying low-temperature ion exchange treatment to the glass substrate (I), and the process of applying a resist pattern to the main surface of the glass substrate (C) using a resist pattern as a fluorescent mask and using the sputtering method. A method for manufacturing an information recording substrate, including a step of completely forming unevenness.