JPH0219965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a mask used, for example, for manufacturing large-scale integrated circuits, with high precision and in a short time using electron beam exposure.

When manufacturing masks using electron beam exposure,
First, a mask blank material is formed by vapor-depositing, for example, chromium on a glass substrate, and after applying, for example, a positive electron beam-sensitive material to the mask blank material, electron beam exposure of a desired pattern is performed. After the exposure, a mask with a desired pattern can be obtained by performing development, etching, and removal of the photosensitive material. If dust adheres to the photosensitive material or chromium during the mask manufacturing process, the chromium will not be completely removed from the glass substrate even when etching is performed on the areas where the dust has adhered, resulting in defective parts of the mask. For this reason, in the past, the manufactured masks were observed using an optical microscope to find defective parts.
The defective portions are irradiated with laser light to vaporize the chromium, which takes a lot of time.

The present invention has been made in view of the above points, and
After applying a positive electron beam-sensitive material to a mask substrate and a mask material made of a photomask substance on the substrate, a first exposure of a desired pattern is performed with an electron beam, and development is performed to expose the mask substrate. After the photomask material has been completely etched and the positive electron beam sensitive material has been removed, the mask material is again coated with the positive electron beam sensitive material, and the first etching process is performed using an electron beam. A second exposure of the desired figure is carried out based on the same reference position in proportion to the exposure, and development, etching of the photomask material, and removal of the positive electron beam-sensitive material are carried out in a short period of time. To provide a mask manufacturing method using electron beam exposure, which can manufacture a highly accurate mask without defects.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIGS. 1 to 11 of the accompanying drawings show the steps of the mask manufacturing method according to the present invention, and FIG.
1 shows a mask blank material consisting of a glass substrate 1 on which is deposited. First, a positive electron beam-sensitive material 3 is applied to this mask material (second
For example, in this step, dust _d1 is attached to the surface of the photosensitive material. The mask material coated with the photosensitive material 3 is placed in an arbitrary electron beam exposure device, and as shown in FIG. 3, the photosensitive material is irradiated with an electron beam 4 to expose a desired pattern. When the material is developed after the exposure, the part of the photosensitive material irradiated with the electron beam is removed, but the part of the photosensitive material to which the dust _d1 has adhered is substantially not sensitized by the electron beam. It remains on the mask material as it is even after the development process (FIG. 4). Note that _d2 is dust newly attached during the development process. After the development process, the material is etched (Figure 5),
Through this treatment, chromium in areas where there is no photosensitive material is removed from the glass substrate 1. At this time, the chromium in the area where the dust _d2 is attached is not removed and remains. After the etching process, the photosensitive material 3 is removed from the mask material (Fig. 6), but the steps up to this point are equivalent to conventional mask manufacturing methods, and the defective parts as chromium residue due to adhesion of dust are removed.
p ₁ and p ₂ exist.

In the present invention, the electron beam-sensitive material 3 is applied again to the mask material manufactured by the process shown in FIG. 6 as shown in FIG. 7. Note that _d3 in the figure is newly attached dust. The material coated with the photosensitive material is again placed in the electron beam exposure apparatus, and exposed in the same pattern as the exposure in the step shown in FIG. 3 (FIG. 8). After the exposure process, development process (Figure 9),
Etching processing (Fig. 10) and exposure material removal processing (Fig. 11) are performed, and the resulting mask has good precision with the defective parts p ₁ and p ₂ shown in Fig. 11 removed. Become.

In this way, in the present invention, processes such as exposure, development, etching, etc. are performed twice on the same mask material, and since it is almost impossible for dust to adhere to the exact same place during the two processes, For example, a defective part that occurred in the first processing step is etched and removed in the second processing step, and
Even if dust adheres to the part to be etched in the second processing step, no new defects will occur in the second processing step because the chromium in that part has not been etched in the first processing step. In the present invention, the exposure of the same figure must be precisely overlapped in the first and second processing steps, but this overlapping exposure can be performed on any part of the material in the first processing step. form any mark,
The second exposure may be performed using this mark as a reference. Also, instead of this mark, a scribe line usually provided on the mask substrate may be used.

The present invention has been described in detail above, but the present invention enables the production of a mask with extremely few defective parts through a simple process of exposing, developing, etching, etc. of the mask material twice, and using a conventional laser. A highly accurate mask can be manufactured in a shorter time compared to the method of removing defective parts.

[Brief explanation of drawings]

1 to 11 show each step of a mask manufacturing method according to an embodiment of the present invention. 1: glass substrate, 2: chromium, 3: photosensitive material,
4: Electron beam.

Claims (1)

[Claims] 1. After applying a positive electron beam-sensitive material to a mask substrate and a mask material consisting of a photomask material on the substrate, a first exposure of a desired pattern is performed with an electron beam, and development is performed to expose the mask substrate. After complete etching of the photomask material and removal of the positive-type electron beam-sensitive material, the mask material is again coated with the positive-type electron-beam photosensitive material and etched with an electron beam for the first time. A second exposure of the desired figure is carried out based on the same reference position, superimposed on the exposure of Mask manufacturing method.