JPS5848919A - Preparation of semiconductor device - Google Patents

Abstract

PURPOSE:To quickly obtain ultra-minute pattern by employing the high resolution electron beam patterning system with low processing capability for miniature part of specified pattern and the ordinary exposure for the rough area. CONSTITUTION:The negative electron beam resist is coated to the material 8 to be processed on the semiconductor substrate 7. After the position alignment 10, the electron beam is irradiated 11 in accordance with a miniature minute pattern. Then, after mask alignment 10 of the window, the light including the wavelength of 180-300mm. is irradiated to the large pattern region. The pattern 9' is obtained by evelopment and the material 8 is etched using the mask 9'. Since the electron beam is irradiated only to the miniature pattern region, the scanning time is curtailed as compared with that for entire part and the ultra-miniature pattern which has not been obtained by the existing method can be formed. In case this method is applied to the positive resist, since the scanning area is narrow, the scanning time is not elongated and high speed patterning can be realized as in the case of negative resist, making high the degree of freedom of selecting resist material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device having a fine pattern on a semiconductor substrate, and particularly to a phosphorography technique for forming a fine pattern with a size of 1 μm or less.

In order to improve the frequency characteristics and degree of integration of semiconductor devices such as IC%LSI, it is necessary to reduce the device dimensions and improve the processing accuracy. The minimum size must be 1#1 or less.

In conventional semiconductor devices, the element size is 2μ or more, and photoring 2-fi technology is used for processing. This is a technique in which a photoresist is coated on a semiconductor substrate, and a predetermined pattern is transferred to the photoresist by irradiating it with ultraviolet light using a photomask on which a predetermined pattern is drawn as a mask. However, with transfer methods that use light, it is difficult to form patterns that are smaller than rounded or one-line patterns with low resolution.An alternative method is to use electron beams or X-rays that have shorter wavelengths than light. started to be taken.

A transfer method using an electron beam is commonly called electron beam phosphorography, and one of the methods is to directly irradiate a wafer substrate with an electron beam while scanning it without using a mask. On the other hand, resists that can form patterns by reacting with electron beams are called electron beam resists, and like photoresists, there are positive resists whose friendly parts dissolve when exposed to electron beams, and negative resists where the electron beam irradiated parts remain. There is. PMMA (polymethyl methacrylate) for positive resist
and PMIPK (polymethyl isopropenyl ketone), and negative resists include CM, PGMA, etc. The resolution of electron beam phosphorography depends on the electron beam resist, but it can resolve down to about 0.2 μm.

However, since the electron beam resist has low sensitivity to electron beams, it takes a very long time to form a pattern on the entire surface of a wafer, and its throughput is extremely inferior to that of conventional photolithography.

An object of the present invention is to provide a method that takes advantage of the high resolution of electron beam phosphorography while compensating for the drawback of low processing power.

That is, a predetermined pattern is divided into a relatively fine pattern area and a much larger pattern area, the fine pattern area is drawn using electron beam lithography, and the large pattern area is drawn using light containing wavelengths of 180 to 300 cm. It is characterized by being formed using photolithography. Since most of the electron beam resists mentioned above react even with deep ultraviolet light of 180 to 300 m, they can also be used in photolithography using deep ultraviolet light.

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 is a diagram of a predetermined chip pattern to be formed on the entire surface of a semiconductor wafer. FIG. 2 shows a state in which the pattern of FIG. 1 is divided into a fine area 2.3.4 and a large pattern area 5. In FIG. Here, 6 is the overlapping part of both.

An example in which the resist is left in the predetermined pattern 1 shown in FIG. 1 will be described below. A negative electron beam resist 9 is applied over the entire surface of the semiconductor substrate 7 having the workpiece 8 on the sK surface shown in FIG. 3(a).

Reference numeral 10 denotes an electron beam ring l) and a positioning pattern used for photography. After alignment using this alignment pattern, a second
Electron beam irradiation is performed according to pattern 2.3.4 in the figure. This irradiated part is 11 in FIG. 3(b). After that, prepare a photomask in which the large pattern area 5 shown in FIG.
After alignment at 0, the resist is photopolymerized by irradiation with light containing a wavelength of 180 to 300 nm. The part irradiated with this light is 12 in FIG. 3(C). When the resist pattern 9' is developed with a predetermined developer, as shown in FIG. remain on top. Thereafter, the workpiece 8 may be etched using the resist pattern 9' as a mask.

On the other hand, a second embodiment in which the same pattern is formed using a positive resist is shown in FIG. Figure 4 2', 3', 4'
indicates a part irradiated with an electron beam by electron beam phosphorography. Reference numeral 5' indicates a portion to which light containing wavelengths of 180 to 300 wavelengths is irradiated using a photomask. Since the area irradiated with the electron beam and light is dissolved by development, a resist with a predetermined pattern of 4° remains on the semiconductor substrate as in the first embodiment.

As described above, in the present invention, the electron beam is irradiated only to the area of the fine pattern of 1 μm or less, and the other areas with a large exposed area are irradiated with light. Furthermore, the scanning time of the electron beam is shortened, and the throughput of the electron beam exposure apparatus is greatly improved. On the other hand, it also becomes possible to form fine patterns that were impossible with conventional photolithography.

Furthermore, the selection of the resist material for K is important for microfabrication, but when there is only a small area to leave resist as shown in this example, a positive resist is used because the irradiation area is large in conventional electron beam phosphorography. However, according to the present invention, the electron beam scanning time is the same for both d-positive and negative types, which means that patterning can be performed at the same high speed as the negative type, and resist The degree of freedom in material selection also increases.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of one element pattern of a semiconductor device, FIGS. 2 and 4 are pattern configuration diagrams showing an embodiment of the present invention, and FIGS. 1A and 1B are cross-sectional views of a semiconductor illustrating an example in the order of steps. 1... Chip pattern, 2.3.4.5...
...Chip pattern division pattern, 6...
Overlapping part of the division pattern, 7... semiconductor substrate,
8-... Work material, 9.9'... Electron beam register), 10... Positioning area, 11...
...Electron beam irradiation area, 12...Light irradiation area.

Claims (1)

[Claims] To form a predetermined resist pattern on a semiconductor substrate, a step of applying a resist on the semiconductor substrate, a step of irradiating a part of a fine region of the resist with an electron beam,
A method of manufacturing a semiconductor device, comprising the steps of: irradiating a region of the resist with light that is larger than the fine region; and then applying the resist.