JPS61292145A - Multi-layered mask - Google Patents

Abstract

PURPOSE:To effectively produce a multi-layered mask with a single mask by forming plural layers of films having different optical transmission char acteristics on the surface of single light transmittable mask substrate, forming mask patterns to be patterned to the respective films and projecting exposing rays of different wavelengths. CONSTITUTION:The multi-layered mask 21 is disposed in the region where the exposing rays are irradiated. The 1st mask 22 which allows the transmission of >=5,000Angstrom wavelength lambda and the 2nd mask 23 which does not allow the transmission of light of <=7,000Angstrom wavelength are formed on the surface of the multi- layered mask. A wafer 24 to be patterned is disposed below the same. The wafer is exposed with the light of <=5,000Angstrom wavelength as the exposing rays so as to be patterned with the 1st mask, then the pattern 25 of the 1st mask is formed on the wafer. The wafer is exposed with the light of 5,000-7,000Angstrom wavelength lambda as the exposing rays so as to be formed with the pattern of the 2nd mask, then the light transmits the 1st mask film 22 and therefore the pattern 26 of the 2nd mask is formed on the wafer.

Description

Detailed Description of the Invention [1111 Main Point 1] The present invention is a multilayer mask in which films having different light transmission characteristics are laminated on a single mask, and each film has a different patterning. Therefore, by sequentially projecting light of different wavelengths onto each of the above films for patterning, multilayer patterning is possible with a single mask without changing the mask.
Additionally, the manufacturing process is streamlined by eliminating the need for mask replacement.

[Industrial Field of Application] The present invention relates to a multilayer mask, and particularly to the structure of a multilayer mask for forming different patterns on the same wafer.

It is well known that photolithography technology has been widely used, especially in semiconductor devices, where different patterns are sequentially layered on a wafer substrate in order to form highly stacked elements. There are many things.

Conventionally, in the patterning process, each time the pattern changes, a different mask is used and patterning is performed each time, but this makes the manufacturing process such as mask replacement and positioning complicated. Improvements are requested.

[Prior art 1] Fig. 3 18) to Fig. 3 1d) are schematic cross-sectional views showing the relationship between a mask and a wafer for performing multiple exposures in the conventional art. A case in which patterning is performed will be explained.

FIG. 3 (al is a cross-sectional view showing exposure for performing the first patterning.

The exposure light beam 1 may be, for example, ultraviolet light, and a first mask 2 is placed within its radiation area, and a patterning 3 is formed on the first mask 2 .

A wafer 4 to be patterned is placed at a predetermined position with a resist film 5 deposited on its surface.

The first mask is irradiated with exposure light as shown by the arrow,
The wafer surface is exposed to light using a first mask,
Subsequently, normal post-development processing steps such as etching are performed.

In FIG. 3), a first pattern 6 is formed on the surface of a wafer 4 using a first mask.

In FIG. 3(C), a second pattern is formed on the surface of the wafer 3 on which the first pattern 6 is formed, using a second mask 7 on which a second pattern 8 is formed. Then, the wafer 3 newly coated with the resist film 9 is coated as shown in FIG.
After exposure and development, etching and other treatments were performed in the same manner as above.

FIG. 3 (dl) is a wafer formed in this manner, and a first pattern 6 and a second pattern 10 are formed on the surface of the wafer 3.

In this way, with conventional exposure methods, when performing multiple different patternings on the same wafer, it is necessary to replace the mask with a different patterned mask each time. The disadvantage is that it takes a lot of man-hours to align the

[Problems to be Solved by the Invention] Conventionally, masks used in photolithography have only a single pattern, and when performing multiple different patterning on the same wafer surface, it is necessary to Since the masks are replaced every time, the number of masks increases, and the number of man-hours required for replacing the masks also increases.

[Means for Solving the Problems] FIG. 1 is a cross-sectional view according to the present invention for solving the above problems, and the means for solving the problems is as follows: , a plurality of films having different light transmission wavelength regions are laminated, and predetermined different patterns are formed on each of the mask films as a first mask (12) and a second mask (13), By sequentially projecting transmitted light having different wavelengths corresponding to the first mask and the second mask according to the process, a plurality of patternings can be performed using a skewer mask.

[Operation 1] In the present invention, a plurality of layers of films having different light transmission characteristics are formed on the surface of a single light-transmitting mask substrate, and each film is patterned according to the order of the manufacturing process. By forming a pattern in advance and projecting exposure light beams of different wavelengths, the wafer can be patterned continuously using a small number of asks. This was designed to streamline the manufacturing process by eliminating the need for replacement.

[Example 1] Figures 1 (al) to 1 (di) are cross-sectional views showing the structure of the multilayer mask of the present invention.

In FIG. 1+al, if a quartz glass plate is used as the light-transmitting material of the mask substrate 11, the light wavelength λ-200
It has the property of transmitting light of 0 Å or more, and the surface of this substrate is polished to a flatness of 5 μm or less at maximum.

In FIG. 1(b), an iron oxide (Pe20 o ) film, for example, is used as the first mask film 12 on the surface of the mask substrate 11, and this is grown to a thickness of about 3000 by CVD. A predetermined first mask pattern 13 is formed.

The light transmission property of this iron oxide is that it transmits wavelengths of λ-5000 Å or more, but does not transmit wavelengths shorter than that.

1dl in FIG. 1 shows a chromium (Cr) film and a chromium oxide (Cr02) film laminated by 600 and 300 layers, respectively, to form the second mask film 14. Predetermined second mask pattern 1 on the surface
However, a mask patterned with chromium cannot transmit light with a wavelength of less than 7000 Å.

In FIG. 1 1dl, a first mask and a second mask are formed on a substrate.

FIG. 2+al to FIG. 2(C) are cross-sectional views for explaining an exposure method using a multilayer mask according to the present invention.

In FIG. 2(a), a multilayer mask 21 of the present invention is placed in the irradiation area of the exposure light indicated by the arrow, but a first mask 22 that transmits wavelengths of λ-5000 Å or more is placed on the surface of the multilayer mask. and a second layer that does not transmit light with a wavelength of 7000 Å or less.
A mask 23 is formed and a wafer 24 to be patterned is placed below it. The pattern 25 of the first mask is thereby formed on the wafer.

Figure 2 (C1 shows that in order to form the pattern of the second mask, exposure was carried out using light with a wavelength of λ -5000 to 7000 mm. At this wavelength, the oxidation of the first mask A second mask pattern 26 is formed to transmit through the iron film 22.

Thereby, a plurality of different patterns can be formed on the wafer by performing exposure with different wavelengths using a single mask.

[Effects of the Invention] As described above in detail, by using the multilayer mask according to the present invention, efficient manufacturing can be performed with a single mask, which has great effects.

[Brief explanation of the drawing]

1 dl to 1 (d+ is a sectional view showing the structure of the multilayer mask of the present invention, and FIG. 2 al to 2 (cl) are sectional views showing the exposure method using the multilayer mask of the present invention. Cross-sectional diagram for Fig. 3i
al~FIG. 3+dl is a schematic cross-sectional view showing the relationship between a mask and a wafer for performing conventional multiple exposures, In the figure, II is a mask substrate, 12 is a first mask film 13
14 is a first mask pattern, 14 is a second mask film, 15 is a second mask pattern, 21 is a multilayer mask, 22 is a first mask, 23
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Claims (1)

[Claims] A multilayer mask characterized in that a plurality of mask films (13) and (15) having different light transmission wavelength ranges and pattern shapes are laminated on the surface of a light-transmitting substrate (11). .