JPS6214824B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a photolithographic mask.

There is a strong demand for pattern processing when processing fine patterns due to the higher frequency and higher integration of semiconductor devices. The minimum dimension that can be industrially uniformly and reproducibly formed on a mask such as a glass mask or metal mask used in photo-etching, which is an essential technology for fine pattern processing. is about 1 micron at the current technological level. Therefore, in order to realize the processing and printing of patterns with submicron dimensions, a photographic etching method using deep ultraviolet X-rays and electron beams with a wavelength of 2000 Å to 2500 Å has been proposed and researched.

Photo-etching method using electron beam, so-called electronic beam
In photolithography, patterns must be formed point by point on a semiconductor wafer with a diameter of 5 to 15 cm, and the time it takes to directly print a pattern over the entire area of a wafer depends on the difficulty of the pattern. However, it usually takes several hours or more. Therefore, the method of directly forming a pattern on a semiconductor wafer using electron beam exposure is not suitable for mass production of semiconductor devices. On the other hand, photo-etching technology that uses deep ultraviolet light and Requires a mask with the same area. In order to form this submicron pattern, it is impossible to use the current method of reducing a large pattern using light due to the problem of diffraction limit. Therefore, in order to form submicron patterns, it is necessary to rely on electron beam exposure.

No matter how precise a mask is, a single pattern includes parts with submicron dimensions and parts with wide dimensions ranging from several microns to several tens of microns. In order to form a submicron pattern by electron beam exposure, the diameter of the electron beam must be further reduced to a fraction of that dimension. Therefore, to form a wide mask,
Like direct exposure onto a semiconductor wafer, it is very time consuming and the cost of manufacturing the mask is very high. Furthermore, since the limit on the number of times a mask can be used is generally several tens of times or less, it has the disadvantage of further increasing the manufacturing cost of the mask, which is a part of a semiconductor device.

The present invention aims to provide a mask with submicron dimensions for use in deep ultraviolet exposure at a low cost, thereby making it possible to easily and inexpensively achieve higher frequencies and higher integration of semiconductor devices.

According to the present invention, large patterns that do not require microfabrication technology can be formed by light exposure, while fine patterns that require microfabrication technology can be formed by electron beam exposure. do.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

A wide pattern or a rough pattern can also be produced by a reduction method using a light exposure method. Therefore, as shown in FIG. 1, first, a wide pattern 1 and an alignment pattern 2 are formed by a reduction method using a light exposure method.

Next, apply resist to the entire surface and use the alignment pattern.
Using the pattern 2 as a reference, a fine pattern 3 is processed by electron beam exposure as shown in FIG. At this time, the resist is dissolved in the portion of the fine pattern 3, and the other resist is hardened. Using this hardened resist as a mask, the original mask material is etched to form a wide pattern 1, as shown in Figure 3.
A mask of a composite pattern 4 including both the pattern 3 and the fine pattern 3 is formed.

The applicant has confirmed that this method allows the relative alignment accuracy of two patterns to be ±0.1 micron, and it is possible to synthesize two patterns with sufficient accuracy for practical use. Further, by transferring the composite pattern described above onto a quartz substrate provided with a mask material by deep ultraviolet exposure, a large number of masks as described above can be easily manufactured. In addition, a mask with good pattern accuracy can be easily produced by creating a rough pattern using a reduction method and using electron beam exposure to create only the parts where pattern accuracy is important.

[Brief explanation of the drawing]

1 to 3 are partial plan views of each process according to an embodiment of the present invention. 1... wide pattern, 2... alignment pattern,
3... Fine pattern, 4... Composite pattern.

Claims (1)

[Claims] 1. A step of forming a first pattern by a light exposure method, and forming a second pattern by electron beam exposure using at least a part of the first pattern as a position reference. 1. A method of manufacturing a mask for manufacturing a semiconductor device, comprising the step of forming a mask in which first and second patterns are synthesized. 2. The method of manufacturing a mask for manufacturing a semiconductor device according to claim 1, characterized in that the mask in which the first and second patterns are combined is replicated using deep ultraviolet light.