JPS6333746A - Production of photomask - Google Patents

Abstract

PURPOSE:To prevent peeling of a shading material layer by providing a step of removing a prescribed thickness of a height supplementing layer and a layer composed of a shading material, and by exposing the surface of a translucent mask substrate except groove parts thereon. CONSTITUTION:A positive type photoresist is coated on the substrate 1 to form a photosensitive resist film 4, and said film 4 is exposed to form a prescribed fine pattern, followed by developing it to leave the resist film 4' at the part except a necessary part. Subsequently, the substrate 1' of the translucent mask is formed by effecting anisotropic etching and forming the groove 5 on the part except the resist film 4'. And then, a shading material layer 2 with an uneven surface is formed by removing the resist film 4', and sticking Cr, Ta, etc., on the substrate 1' forming the groove 5. And, then, the positive type photoresist is coated, thereby forming a height supplementing layer 6 to give uniform height. Finally, the layer 6 and the shading material layer 2 are both etched and removed, while maintaining even height of said films, until the surface of the translucent mask substrate 1' is exposed while leaving the shading material layer 2' in the groove 5. Thus, the photomask having a long shelf life and less tendency for peeling of the mask pattern is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a photomask, and particularly to a method of manufacturing a photomask used in a pattern exposure step (lithography) in the manufacturing process of an optical disk.

Conventional technology 4th EIUfa) shows a conventional photomask 20.

This photomask 20 is manufactured by the following method.

First, as shown in FIG. 4 1'b, Cr,
A light-shielding material layer 2 is formed by depositing a light-shielding material such as Ta by vapor deposition, sputtering, or the like.

Next, as shown in FIG. 4 1'b), a photosensitive resist film 3 is formed on the upper surface of the light-shielding material layer 2.

Next, a desired fine pattern is projected onto the photosensitive resist film 3, exposed and developed to form a resist film 3' with only necessary portions left as shown in FIG. 41'b.

Next, etching is performed using an ion beam or the like to remove the portions of the light-shielding material layer 2 where there is no resist film 3', leaving only the necessary portions of the light-transmitting material layer 2' as shown in FIG. 4fd+. shall be.

Finally, the resist layer 3' is removed using an organic solvent or plasma method.

As a result, the photomask 20 as shown in FIG. 4(e)
is obtained.

Problems with the Prior Art In the conventional photomask 20, as can be understood from FIG.
It has a structure in which "f2" is attached.

That is, it has a structure in which a light-shielding material layer 2' constituting a desired fine pattern protrudes to the outside.

Therefore, when external force is applied due to cleaning of the photomask 20, etc., there is a problem that the light-shielding material layer 2' is likely to peel off.

OBJECTS OF THE INVENTION An object of the present invention is to provide a method for manufacturing a photomask that does not cause peeling of a light-shielding material layer, has high reliability, and has a long life.

Structure of the Invention The method for manufacturing a photomask of the present invention includes a step of forming a resist layer on a transparent mask substrate, a step of forming a desired pattern on the resist layer by exposure and development, and a step of forming a transparent photomask by anisotropic etching. A step of forming grooves with a desired pattern on the mask substrate, a step of removing the resist layer on the transparent mask substrate, a step of forming a light-shielding material layer on the transparent mask substrate with grooves of the desired pattern formed, and a surface a step of forming a supplementary layer on the light-shielding material layer so that the heights are approximately equal;
The method is characterized in that it comprises a step of removing a predetermined thickness of the supplementary layer and the light-shielding material layer by etching to expose the surface of the light-transmitting mask substrate other than the groove portion. .

Function: The photomask manufacturing method of the present invention can be implemented by applying the technology of conventional photomask manufacturing methods, so it has the advantage of requiring less burden on new equipment and being easy to implement.

EXAMPLES Hereinafter, the present invention will be explained in more detail based on examples shown in the drawings. Here, FIG. 1 is a cross-sectional view of each step of an embodiment of the photomask manufacturing method according to the present invention, and FIGS. 2 and 3 are modified examples of the photomask obtained by the method of the present invention. 2 is a sectional view showing the present invention. Note that the present invention is not limited to the embodiment shown in the figure.

The method for manufacturing a photomask of the present invention will be explained in order with reference to FIGS.

First, as shown in FIG. 1, a positive photoresist is coated by a spin code method or the like on a flat transparent mask substrate 1 made of a material such as quartz or glass, and a photosensitive resist film 4 is formed. form.

Next, an electron beam is applied onto the photosensitive resist film 4.

A desired fine pattern is exposed using a laser beam or the like and developed to form a resist film 4' with only the necessary portions left as shown in FIG.

Next, the transparent mask substrate 1' is subjected to anisotropic etching such as dry etching, and as shown in FIG.
shall be.

Next, as shown in Figure 1 (dl), ashing (ashing)
The resist Ij14' is removed by etching or the like.

Next, as shown in the first ffl (e+), a light-shielding material layer 2 is formed by depositing Cr, Ta, etc. by vapor deposition, sputtering, etc. on the light-transmitting mask substrate 1' in which the groove 5 is formed. In the embodiment, the light-shielding material layer 2 is smaller than the depth d of the groove 5.
The thickness t is made large. Light-shielding material layer 2
The surface becomes uneven in accordance with the unevenness of the light-transmitting mask substrate 1'.

Next, a material having an etching rate similar to that of the light-shielding material N2, such as a positive type photoresist, is coated by a spin code method or the like, and as shown in FIG. A supplementary layer 6 of uniform height is formed.

Finally, when the supplementary layer 6 and the light-shielding material layer 2 are etched by dry etching or the like, since the etching rate of both layers is equal, both layers are removed while maintaining the same height, and this is done for a certain amount of time. If this is done, the surface of the light-transmitting mask substrate 1' will be exposed and the light-shielding material layer 2' will remain in the groove 5, as shown in FIG.

In this way, the photomask 10 according to the present invention is obtained.

In this photomask 10, as understood from FIG. 1 Fg+, the light-shielding material layer 2' constituting the desired fine pattern is located in m5 and does not protrude from the surface of the light-transmitting mask substrate 1'. Therefore, even if external force is applied due to cleaning or the like, it will not peel off.

Figure 2 shows another photomask 1 obtained by the method of the present invention.
1, the surface height of the light-shielding material layer 2' is below the surface of the light-transmitting mask substrate 1'. Such a photomask 11 is shown in FIG.
It can be manufactured by making the etching rate of the light-shielding material layer 2 larger than the etching rate of the light-shielding material layer 2.

FIG. 3 shows still another photomask 12, in which the thickness t of the light-shielding material layer 2 in FIG. It can be manufactured by making the diameter smaller than d.

As yet another embodiment of the present invention, after FIG. 1(e),
By polishing, without going through the process shown in Figure 1 tfl,
One example is the one that makes the state shown in FIG. 1 tgl.

Effects of the Invention According to the present invention, a step of forming a resist layer on a transparent mask substrate, a step of forming a desired pattern on the resist layer by exposure and development, and a step of forming a desired pattern on the transparent mask substrate by anisotropic etching. A process of forming grooves in a pattern, a process of removing the resist layer on the transparent mask substrate, a process of forming a light-shielding material layer on the transparent mask substrate on which the grooves of the desired pattern have been formed, forming an auxiliary layer on the light-shielding material layer so as to have the same height, and removing a predetermined thickness of the auxiliary layer and the light-shielding material layer by etching to expose the surface of the light-transmitting mask substrate other than the groove portion; process,
Provided is a method for manufacturing a photomask, comprising:

As a result, a photomask with high reliability and long life can be obtained without causing peeling of the mask pattern. Furthermore, according to the method of the present invention, the edge shape of the mask pattern can be formed accurately and problems such as poor conductivity do not occur, and all etching can be performed by dry etching, so there is no problem with waste liquid, etc., and it is not practical. This is an excellent method.

[Brief explanation of the drawing]

Figures 1+a) to (along are cross-sectional views at each step of an embodiment of the photomask manufacturing method according to the present invention, and Figures 2 and 3 are cross-sectional views of other photomasks obtained by the method of the present invention. , FIG. 4 shows the first diagram of an example of a conventional photomask manufacturing method. (Explanation of symbols) 1.1'...Transparent mask substrate 2.2'... Light-shielding material layer 3.3'...Resist film 4.4'...Resist film 5...Groove 6...Supplementary layer 10.11.12...Photomask 20...Conventional photo mask.

Claims (1)

Scope of Claims: (a) a step of forming a resist layer on a transparent mask substrate; (b) a step of forming a desired pattern on the resist layer by exposure and development; (c) a step of forming a transparent resist layer by anisotropic etching. (d) removing the resist layer on the light-transmitting mask substrate; (e) forming a light-shielding layer on the light-transmitting mask substrate with the desired pattern of grooves formed; (d) removing the resist layer on the light-transmitting mask substrate; (f) forming a supplementary layer on the light-blocking material layer so that the surface has a substantially uniform height; (g) etching the supplementary layer and the light-blocking material layer to a predetermined thickness; A method for manufacturing a photomask, comprising the step of: removing the surface of the light-transmitting mask substrate other than the groove portion, and exposing the surface of the light-transmitting mask substrate other than the groove portion.