JPH02228657A - Mask - Google Patents

Abstract

PURPOSE:To reduce the approaching effect at the time of pattern preparation and to eliminate the sticking of dust to a pattern surface and the scratching of a pattern by complementarily separating the fine pattern, and adhering the upper and lower substrates. CONSTITUTION:The objective pattern is formed by superposing the front and rear surfaces of the transparent substrates 8 and 9 where prescribed fine patterns are respectively formed. For example, where plural patterns 10 and 11 are arranged at the intervals equal to or less than several microns, the patterns are formed alternately at every other one on the front and rear substrates; where fine patterns are arranged right near a large pattern, the large and small patterns are complementarily formed on the front and rear transparent substrates, and the fine pattern surfaces of the transparent substrates are adhered to each other. Thus, the influence of the approaching effect is reduced, and the sticking of dust to the fine pattern surface and the scratching of the pattern are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a mask such as a photomask or a reticle mask, which has a fine light-shielding pattern formed on a transparent substrate and is used in the manufacture of semiconductor integrated circuits.

As a specific field of use, it can be applied to original plates for semiconductor integrated circuits, other electronic devices, etc.

<Prior Art> Conventionally, when forming fine patterns on photomasks and reticles, pattern formation is performed using an electron beam lithography system.

However, especially when patterns are lined up at intervals of several microns or less, or when a fine pattern is placed very close to a large pattern, the pattern may not be formed or be distorted due to the proximity effect caused by electron beam scattering. There was a problem.

Further, since the pattern surface of conventional photomasks and reticles is exposed, there are problems such as dust getting on the pattern or damaging the pattern during transportation or transfer. Attempts have been made to solve this problem by attaching a pellicle, but this has resulted in problems such as dust being generated from the pellicle.

<Problems to be Solved by the Invention> The present invention is intended to solve the above-mentioned drawbacks of conventionally known photomasks or reticles. This was done to reduce the influence of the proximity effect when fine patterns are placed nearby, and to prevent dust from getting on the pattern surface and damaging the pattern.

Means for Solving the Problems The present invention attempts to form a desired pattern by overlapping two transparent substrates, each having a predetermined fine pattern formed thereon, on the front and back sides. For example, if multiple patterns are lined up at intervals of several microns or less, the patterns may be formed on the front and back two substrates at different intervals, or if a fine pattern is placed very close to a large pattern, Small patterns are formed complementary to each other on two transparent substrates, and the fine patterned surfaces of the transparent substrates are bonded together.

By doing this, a photomask with a fine pattern,
A reticle can be created efficiently, and the problem of dust on a pattern can be solved.

<Detailed Description of the Invention> The bonded reticle and photomask of the present invention will be explained based on the drawings shown in FIGS. 1 to 15.

Here, as an example, a reticle in which patterns are arranged at intervals of several microns or less and includes a mixture of large and small patterns will be explained.

FIG. 15 is an overall diagram thereof. Figures 1 and 2 show the ideal shape of a part of the pattern. In some cases.

In the conventional technique, that is, when a pattern is formed on one substrate by the electron beam groove drawing method, FIG.
As shown in FIG. 4, it is not possible to form a fine pattern with a positive value due to the influence of the proximity effect.

FIG. 5 is a cross-sectional view of a conventional reticle, but if dust 3 gets on the pattern 2 due to carrying the mask, etc., the dust 3 will be on the pattern 2, so it will not only be on the pattern 2 but also on the dust 3 during transfer. This causes the dust 3 to be transferred as well. Figure 6 shows a pellicle 4 pasted on the mask and reticle, but the dust 7 on the pellicle 4 is out of focus during transfer. However, if there is dust 6 on the pattern 2 that comes out from the pellicle support foam 5 when the pellicle support foam 5 is pressed against the substrate 1, it will be transferred. In the present invention, as shown in FIGS. 9 and 10, and FIGS. 12 and 13, the fine patterns are complementarily decomposed, and as shown in FIGS. 7 to 8. The upper substrate Fi8 and the lower substrate 9 are bonded together. By doing so, a predetermined pattern as shown in FIGS. 11 and 14 can be obtained.

Here, in FIG. 11, the spacing between the patterns can be increased as in FIGS. 9 and 10, and
In the drawings, since large patterns and small patterns can be separated as shown in FIGS. 12 and 13, the influence of the proximity effect can be reduced. Further, even if dust is deposited on the substrate as shown in FIG. 8, it will not be transferred because it will not be in focus during transfer.

Here, the adhesive shown in FIG. 7 is preferably colorless and transparent, and it is preferable that the upper substrate Fi8 and the lower substrate 9 are overlapped at predetermined alignment marks 17, 20, 28 and strongly pressed together. The fine pattern on the upper substrate shown in FIG. 12 must be formed on the opposite side of the desired pattern.

<Example> As an example of the bonded reticle and photomask of the present invention, a 5-inch square reticle in which patterns are arranged at intervals of several microns or less will be described as an example.

5-inch square quartz glass substrate with chrome film, Toppan Printing Co., Ltd. product name 5009-QZ-TI (R3 coated with electron beam resist and Chisso PBS to a specified thickness using a spin code method, pre-baked as specified) Prepare two coated pieces.

The final shape of the pattern to be created is shown in FIG. 1, with a pattern width of 0.5 μm and a pattern pitch of 1.0 μm.

A pattern is drawn on one substrate, as shown in FIG. 9, and on the other substrate, as shown in FIG. 10, using an electron beam drawing device PerkinElmer 93 FIEBES m at a predetermined electron beam dose. At this time, the width of the pattern is 0.5 μm and the pitch of one pattern is 2.0 μm.

After development with a predetermined developer and rinse solution, a predetermined post-bake treatment is performed, and the chromium layer is etched with a predetermined etching solution.

After stripping the resist layer with a specified stripping N solution, cleaning is performed,
The middle of the pattern is 0.5 μm, the pitch of the pattern is 2.0
One substrate each having a pattern of μm shown in FIGS. 9 and 10 was obtained.

An ultraviolet curing type transparent adhesive, Loctite 358 manufactured by Nippon Loctite, is applied to the entire surface of the patterned chrome film on the two substrates at a predetermined thickness using a roll coating method or a spin code method. While aligning the two substrates using alignment marks 17, the patterned chrome film surfaces are overlapped and pressed together. At this time, it is desirable to use a Teflon substrate as the crimp substrate. As above, the 11th
The pattern shown in the figure was obtained.

After crimping, the adhesive protruding from the substrate is wiped off and the entire surface is irradiated with ultraviolet rays of a predetermined wavelength from the front and back.

That is, the adhesive is cured.

As described above, it is possible to obtain a reticle having a fine pattern, no dust on the pattern, and no possibility of the pattern being scratched.

It goes without saying that the present invention is not limited to implementation.

<Effects of the Invention> As can be seen from the above description, according to the present invention, the proximity effect during pattern creation is reduced, so photomasks and reticles that require fine patterns can be provided in complete form.
The effective industrial significance of the present invention is that there is no dust on the pattern and there is no possibility of scratches.

Naturally, dust adhering to the outer surface of the substrate is not transferred to the semiconductor element.

[Brief explanation of the drawing]

Figure 1 is an enlarged plan view showing an example of a fine pattern;
The figure is an enlarged plan view showing another example of a fine pattern, FIGS. 3 and 4 are enlarged plan views showing the proximity effect when a pattern is created by a conventional method, and FIG. 5 is an enlarged plan view showing a conventional reticle. FIG. 6 is an enlarged view of a part of the mask, and FIG. 6 is an enlarged view of the main part when a pellicle is attached to a conventional reticle mask. FIG. 8 is a partially enlarged sectional view showing the mask after bonding according to the present invention, and FIG. 9 is a partially enlarged sectional view showing the upper substrate pattern among the patterns formed by dividing the fine pattern of FIG. 1 according to the present invention. The enlarged plan view shown in FIG. 1O is an enlarged plan view showing the lower substrate pattern among the patterns formed by dividing the fine pattern shown in FIG.
Figure 1 is an enlarged plan view showing a fine pattern obtained by pasting together the patterns in Figures 9 and 10 according to the present invention, and Figure 12 is an enlarged plan view showing a fine pattern formed by dividing the fine pattern in Figure 2 according to the present invention. FIG. 13 is an enlarged plan view showing the upper substrate pattern among the patterns obtained by dividing the fine pattern shown in FIG. 2 according to the present invention, and FIG. , according to the present invention, the first
FIG. 15 is an enlarged plan view showing a fine pattern obtained by bonding the patterns of FIG. 2 and FIG. 13 together, and FIG. 15 is a perspective view showing an embodiment of the bonded reticle and photomask of the present invention. 1 Substrate 2 Pattern 3 Dust on the pattern 4 Pellicle 5 Foam for pellicle support 6 Dust from the foam for pellicle support 7 Dust on the pellicle 8 Upper substrate 9 Lower substrate 10 Pattern on the upper substrate 11 Pattern on the lower substrate 12 Adhesive 13 Dust on the upper substrate 14 Adhesive layer 15 Pattern on the upper substrate 16 Position 17 where the patterns on the lower substrate are bonded together
Alignment mark 1st Position where the patterns on the upper substrate are bonded together Pattern on the lower substrate Alignment mark Pattern on the upper substrate Location where the patterns on the lower substrate are bonded Location where the patterns on the upper substrate are bonded Pattern on the lower substrate Upper substrate pattern forming section Lower board alignment mark patent application Toppan Printing Co., Ltd. Representative Kazuo Suzuki Figure 5 Figure 8 Figure 1 Figure 2 Figure 3 Figure 4' Figure 15

Claims (1)

[Claims] (1) A mask characterized in that it is formed by joining the fine patterned surfaces of two transparent substrates each having densely adjacent fine patterns formed complementary to each other.