JPH0440456A - Manufacture of photomask - Google Patents

Abstract

PURPOSE:To prevent occurrence of dust from a resist and chromium in manufacture processes after development by exposing a positive resist in a specified width from the border of the mask blank after coating it with the resist, and developing this exposed part together with the exposed part for patterning and etching them. CONSTITUTION:The mask blank 8 obtained by forming a chromium layer 3 on a glass substrate 4 is coated with the positive resist 2, the constant width L from the border of the blank is exposed to electron beams 1 at the same time of exposing for patterning, and the resist pattern 5 is formed by development 9, and the exposed resist part 6 of the circumference of the mask is removed by the development and etching 10, and likewise the chromium part 7 on the circumference of the mask is removed, thus permitting occurrence of dust due to friction of the resist and chromium with a conveying system in the following manufacturing processes to be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a photomask, particularly one used in the manufacture of semiconductors.

2. Description of the Related Art Conventionally, this type of photomask has been manufactured by applying a positive resist onto a mask blank, exposing the resist to an electron beam to form a pattern, and then developing and etching the resist.

Figure 4 fal ~ Figure 4 (C1) shows a conventional method of manufacturing a photomask. When a positive resist 2 is applied and developed after being irradiated with an electron beam 1, a resist pattern portion 5 is formed as shown in FIG. The chromium layer 3 in the irradiated portion is removed and a chrome pattern portion 6 is generated.

FIG. 5 (al is a plan view of the conventional negative mask made as described above, and FIG. 5(b) is a side view of the same. In FIG. 5, chromium 3 is placed on the glass substrate 4. , a chrome pattern portion 6 is formed.

Conventional negative masks have been manufactured by exposing only the patterned surface to electron beams as described above.

Problems to be Solved by the Invention In such a conventional configuration, the chrome film is still formed on the end faces of the photomask, so when the photomask is transported after pattern formation, there is a risk of contact between the end faces of the photomask and the transport system. The chromium may peel off due to friction and become dust, which may adhere to the photomask and cause defects. Furthermore, since the resist is also applied to the end face portions during pattern formation, the resist adheres to the transport system during the transport of the photomask, making it easy to generate dust, which leads to the first problem of mask defects. was.

The present invention solves these problems, and provides a manufacturing method that prevents resist from adhering to the transport system during the photomask manufacturing process, and a photomask that prevents chromium from peeling off at the edge of the mask. The purpose is to provide

Means for Solving the Problems In order to achieve this object, the photomask manufacturing method of the present invention applies a positive resist onto a mask blank, and then coats the positive resist from the end face of the mask blank to the chuck part of the conveyance system. The chromium layer on the end face is removed by electron beam exposure with a certain width, development, and etching.

Effect: By using this method, the resist is removed by development and the chromium is removed by etching from the area exposed to the electron beam from the end face of the mask blank to a certain width corresponding to the chuck part of the transport system. It is possible to eliminate the generation of resist and chrome dust.

Embodiment An embodiment of the present invention will be described with reference to the drawings. Figure 1fa
FIGS. 1 to 1tc+ show cross-sectional views of a photomask according to an embodiment of the present invention in the order of steps.

As shown in FIG. 1 (al), a positive resist 2 is applied to a mask blank in which a chromium layer 3 is formed on a glass substrate 4 by vapor deposition or sputtering, irradiated with an electron beam 1, and then developed. (A resist pattern portion 5 is formed as shown in BL. When this is etched, the chromium layer 3 in the electron beam irradiated portion is removed as shown in FIG. 1 (C1), and a chrome pattern portion 6 is generated. After applying a positive resist 2 thereon, at the same time as exposure with an electron beam 1 for pattern formation, the positive resist 2 is exposed to an electron beam over a certain width from the end face of the mask planx.

FIG. 2 shows the exposed area around the mask. In FIG. 2, there is an exposed portion 7 on the end face, and the width exposed from the end face of the mask corresponds to the width of the chuck of the transport system. Next, when development is performed, a resist pattern portion 5 is formed, and the resist in the exposed portion 7 around the mask is removed. Finally, etching is performed to form a chrome pattern portion 6 and remove the chrome removed portion 7 around the mask. The plan view and side view of the negative mask after pattern formation are shown in Figure 3 ta+ and Figure 3.
As shown in the figure (bl), the chromium layer around the mask has been removed so that no dust is generated during transportation.

Note that exposure is not limited to electron beams, and light such as ultraviolet rays may also be used.

Effects of the Invention As is clear from the description of the embodiments above, according to the manufacturing method of the present invention, the lens and chromium in the exposed area around the mask are removed, and in the manufacturing process after development, the contact with the transport system is removed. It is possible to eliminate the generation of resist and chrome dust due to friction. As a result, it is possible to reduce defects in the mask caused by adhesion of dust.

[Brief explanation of drawings]

Figure 1 (al to (C1) is a cross-sectional view of a photomask showing the manufacturing process of one embodiment of the manufacturing method of the present invention, Figure 2 is a plan view of this example, and Figure 3 (al and fbl are plane views, respectively). Figures and cross-sectional views, Figures 4 (al~(C1 is a cross-sectional view showing the conventional manufacturing process, Figures 5 (a) and (bl) are a plan view and a cross-sectional view of a photomask for explaining the conventional technology, respectively. 1...Electron beam, 2...Positive resist, 3...Chromium layer, 4...Glass substrate, 5...Resist pattern Part 6...
-Chrome pattern part, 7... Chrome layer removed part. Name of agent: Patent attorney Shigetaka Awano Funeral map for one person

Claims (1)

[Claims] A method for manufacturing a photomask, in which a positive resist is applied onto a mask blank, the positive resist is exposed to light over a constant width from an end face of the mask blank, and the exposed portion is developed and etched at the same time as the exposed portion for pattern formation.