JPH05243115A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make pattern dimensions uniform by a method wherein the prescribed pattern, to be transferred to a photosensitive organic material film through a mask, is composed of a plurality of masks, and the prescribed patterns are formed by conducting an exposure process and a developing treatment on each mask. CONSTITUTION:The first exposure is conducted on a silicon semiconductor substrate on which a positive type photoresist is spin-coated using the first exposure reticle 12a. Then, the second exposure is conducted on the silicon semiconductor substrate on which the first exposure is finished using the second exposure reticle 12b. The position of pattern is arranged by shifting downward the pattern of the first exposure reticle. The second hole pattern should be designed in such a manner that it is positioned in the middle of the hole pattern formed by the first exposure. After exposure, the photoresist on the exposed part of the semiconductor substrate is removed by an alkaline developing solution, and a pattern is formed on the prescribed position without receiving proximity effect. As a result, the problem of proximity effect can be removed, and the dimensional irregularity can be lessened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a lithographic process technique.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a semiconductor substrate for each manufacturing flow of a conventional semiconductor device. The manufacturing process of the semiconductor device is as follows. A photosensitive organic film called a photoresist 32 is spin-coated on the semiconductor substrate 31 (FIG. 3A). Next, the glass substrate is exposed to ultraviolet rays through a reticle 33 in which a predetermined chrome pattern 34 is arranged (FIG. 3B). Next, the predetermined photoresist pattern 32 was formed by removing the photoresist film in the portion exposed by the alkaline developer (FIG. 3C).

[0003]

In the conventional method for forming a pattern of a semiconductor device, light transmitted through a reticle in which a repetitive pattern is designed is mainly transmitted in a lateral direction by Fraunhofer diffraction when performing reduction projection exposure using a stepper. A phenomenon occurs in which the light spreads and the intensity of light in the portion that should originally be shielded increases. This phenomenon tends to occur in the case of a repeated pattern having a small pattern size and a narrow pattern interval.

Therefore, the intensity distribution of the light projected on the semiconductor substrate is not a discontinuous value represented by 1 or 0,
It becomes continuous, and the sizes of the repeated patterns that are originally formed with the same size are different from each other, or the pattern cannot be resolved. Therefore, in a semiconductor device having many repeating patterns, the pattern size of each element is different on the semiconductor substrate, and uniform electric characteristics cannot be obtained, and it becomes difficult to manufacture a highly reliable semiconductor device.

An object of the present invention is to provide a pattern forming method which makes it possible to make the pattern size of a repetitive pattern uniform and to make the pattern highly integrated.

[0006]

According to a method of forming a pattern of a semiconductor device of the present invention, a repetitive chrome pattern originally arranged on a single glass reticle is divided into a plurality of patterns, and adjacent patterns are mutually separated. The method includes a step of exposing a plurality of times using a plurality of reticles in which the pattern density per reticle is reduced so that there is no influence and the interval between adjacent patterns is widened.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described with reference to the drawings. Figure 1
(A)-(c) is a figure which shows the 1st Example of this invention, The top view (a) of the photoresist pattern formed on a silicon semiconductor substrate in the contact formation process at the time of MOS integrated circuit manufacture, and (a). It is a top view (b), (c) of the mask used for exposure. In FIG. 1A, the pattern of the positive photoresist 11 on the silicon semiconductor substrate is a hole pattern having dimensions x (μm) xz (μm), and the pattern interval is y (μm).

The exposure light has a wavelength of 365 nm and a numerical aperture of 0.
In the case of No. 45, the problem when the pattern is formed on the semiconductor substrate is when the dimension x (μm) is about 0.8 μm or less and the pattern interval y (μm) is equal to x (μm). Here, in the case of 5: 1 reduction projection exposure, the hole interval y
Shows the pattern forming method when is equal to the hole dimension x (μm).

First, the first exposure reticle 12a is used to perform a first exposure on a silicon semiconductor substrate spin-coated with a positive photoresist. The mask pattern of the first exposure reticle 12a is designed to have a hole pattern a on the reticle.
(Μm) = 5 × (μm), hole spacing b (μm) = 3a
(Μm). Then, the second exposure reticle 12b is used to perform the second exposure on the silicon semiconductor substrate for which the first exposure has been completed. The dimension a (μm) of the contact holes and the hole interval b (μm) of the second exposure reticle 12b used at this time are the same as those of the first exposure reticle 12a.

The positions of the patterns are arranged such that the patterns of the first exposure reticle are shifted in the downward direction of the drawing by 2a (μm), and the second hole pattern is located in the middle of the hole pattern formed by the first exposure. Designed to be located. The post-exposure silicon semiconductor substrate is formed by removing the photoresist in the exposed portion using an alkaline developing solution and forming a pattern at a predetermined position without the proximity effect.

2A to 2C are views showing a second embodiment of the present invention. In this embodiment, a step of forming a gate electrode when manufacturing a MOS integrated circuit is shown. The arrangement of the pattern on the reticle and the exposure method are the same as in the first embodiment. In this embodiment, a negative photoresist 21 is used to form a line pattern. Therefore, the first exposure reticle 23a and the second exposure reticle 23b are formed with the blank patterns 24a and 24b.

[0012]

According to the present invention, in a repetitive pattern in which the proximity effect occurs, the first exposure reticle and the chrome of the first exposure reticle in which patterns having a sufficiently wide interval that does not cause the proximity effect are arranged in advance are covered. A second exposure mask in which the remaining patterns to be formed in the open space are arranged is formed, and the proximity effect is eliminated by performing multiple exposures using the mask, and there is little dimensional variation and the degree of integration is high. This has the effect of forming a high-quality pattern.

[Brief description of drawings]

FIG. 1 is a plan view (a) of a semiconductor substrate and plan views (b) and (c) of a mask according to a first embodiment of the present invention.

FIG. 2 is a plan view (a) of a semiconductor substrate and plan views (b) and (c) of a mask according to a second embodiment of the present invention.

FIG. 3 is a process flow diagram (a) to (c) of the related art.

[Explanation of symbols]

11 Positive Photoresist 12a, 23a First Exposure Reticle 12b, 23b Second Exposure Reticle 13a, 13b Contact Hole Pattern 14 Contact Hole Position on First Exposure Reticle 21 Negative Photoresist 22 Silicon Semiconductor Substrate 24a, 24b gate removal pattern 25 gate removal pattern on first exposure reticle 31 semiconductor substrate 32 photoresist 33 reticle

Claims (1)

[Claims] 1. A step of exposing a photosensitive organic material film on a semiconductor substrate through a mask so that a predetermined pattern is formed from a plurality of masks, and exposing each of the masks. A step of developing the film to form the predetermined pattern, the method for manufacturing a semiconductor device.