JPS6266442A - Photomask for optical memory element - Google Patents

Abstract

PURPOSE:To prevent the defective adhesion between a resist and photomask by preliminarily forming a notch to the position of the photomask where said mask faces the projecting part of the resist. CONSTITUTION:A groove 8 for absorbing the build-up part of the resist 6 is formed to the place of the photomask 7 where the mask faces the end part of a glass disk 1 to eliminate the defective adhesion. The groove 8 has 4mm width from 127mm diameter if the disk 1 is 130mm+ or -0.1mm and the depth thereof is preferably about 0.2-0.5mm. In short, such groove can be formed simply by providing the part to absorb the build-up part of the resist 6 at the end of the disk 1 to the photomask. The pattern for the guide tracks and track addresses of an optical memory element is thereby satisfactorily transferred to the resist film coated on a substrate for the optical memory element by using the photomask.

Description

[Detailed Description of the Invention] Technical Field> The present invention provides at least one method for recording, reproducing, and erasing information using light.
The present invention relates to an optical memory element that performs two operations, and more particularly relates to a photomask used when transferring patterns such as guide tracks or track addresses onto a substrate of an optical memory element.

<Technical background of the invention and its problems> In recent years, the need for optical memory devices as high-density, large-capacity memory devices has been increasing year by year. This optical memory device can be divided into three types depending on its usage: read-only memory, additionally recordable memory, and rewritable memory.

Among these, optical memory elements used as additional recordable memory and rewritable memory usually have a guide track on the substrate of the optical memory element in order to guide a light beam for recording and reproducing information to a predetermined position of the optical memory element. ing. Further, in order to identify the track number of this guide track, information indicating the track address is often written in a part of the guide track.

One of the manufacturing methods for forming this guide track on the substrate of an optical memory element is a method disclosed in Japanese Patent Laid-Open No. 59-210547. This will be briefly explained using FIG. First, Figure 5 (
As shown in a), a resist film 2 coated with a spinner or the like is formed on a glass disk 1, and then as shown in FIG. The pattern of the guide tracks and track addresses (indicated by 5 in the figure) of the photomask 3 is transferred to the resist 2 by irradiating the glass disk 1 with the Shiba line 4 through the resist 2, and then as shown in the figure (c). After developing resist 2, as shown in the same figure (d), CF4 and CH
Mark guide tracks and track addresses on glass disk 1 using adhesive ion etching in F3 gas.
Finally, remove the resist 2 remaining in the step of the same figure (d),
A substrate is formed as shown in FIG. 2(e).

The technical difficulty in this conventional method is shown in Figure (b).
This is the process of transferring the guide track and track address patterns. That is, it is desirable that the photomask 3 and the resist 2 are in close contact with each other, but in the past, as shown in FIG. Poor adhesion between the resist film 2 and the photomask 3 often occurred.

The width of this poor adhesion portion is about 1 to 2 fi. In the photomask 3 shown in the figure, patterns such as guide tracks are omitted.

Purpose of the present invention The present invention solves the above-mentioned conventional drawbacks, and an object of the present invention is to provide a photomask that prevents poor adhesion between the resist and the photomask due to the rise of the resist on the end face of a glass disk.

<Example> Hereinafter, an example of a photomask for an optical memory device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partially enlarged sectional view of an embodiment of a photomask for an optical memory device according to the present invention. As shown in the figure, a groove 8 for absorbing the rising portion of the resist 6 is formed in a portion of the photomask 7 facing the end of the glass disk 1, thereby eliminating poor adhesion.

For example, the glass disk 1 has this groove 8 with a diameter of σ130m±0.
In the case of 1m, as shown in Figure 2, it has a width of 4m from a diameter of 127cm, and a depth of 0.2~0.5cm.
It is desirable that it be about ■. Of course, the cross-sectional shape of this groove does not necessarily have to be rectangular as shown in Figure 2;
) The cross-sectional shape may be triangular as shown in Figure 3 (
It may be semicircular as shown in b). In short, the photomask may be provided with a portion that absorbs the rising portion of the resist 6 at the end of the glass disk 1. Therefore, it is also possible to make the ends of the photomask 7 thinner than the center of the mask as shown in FIG. 4, and to absorb the rising portion 6 of the resist 6 at the thinner portions.

<Effects> According to the present invention, patterns of guide tracks and track addresses of an optical memory element can be successfully transferred to a resist film coated on a substrate for an optical memory element using a photomask.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged cross-sectional view of an embodiment of a photomask for an optical memory element according to the present invention, and FIG. 2 is a cross-sectional view of the entirety thereof.
3 and 4 are partially enlarged sectional views of other embodiments, FIG. 5 is an explanatory diagram of a conventional guide track forming procedure, and FIG. 6 is a partially enlarged sectional view of a conventional photomask. In the figure, 1. Nigarasu disk 2. Resist mask 3: Photomask 4: Shigai line 5: Pattern 6: Resist 7 Two photomask 8: Mizo agent Patent attorney Aihiko Fukushi (and 2 others) Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A photomask for transferring a pattern to a resist film applied to a substrate, the photomask having cutouts formed in advance at positions corresponding to the convex portions of the resist film. A photomask for optical memory devices characterized by: