KR100742090B1 - Method of manufacturing photoresist patterns - Google Patents

Abstract

A method of manufacturing a photoresist pattern having minute spacing or line width is disclosed. The disclosed invention includes applying a photoresist film on a semiconductor substrate. Next, a first reticle is disposed so that the first region of the photoresist film is exposed, and the first region of the exposed photoresist film is irradiated with light having an intensity less than or equal to resolvable intensity. Thereafter, the first reticle is removed and a second reticle is placed so that a portion of the first region and the second region are exposed. Thereafter, a portion of the exposed first region and a second region are irradiated with light having an intensity less than the resolution that can be resolved, and then the photoresist film is developed to remove the overlapped portions of the double irradiated light, thereby forming a photoresist pattern. To form.

Fine spacing, photoresist, double exposure

Description

Method of manufacturing photoresist patterns

1 is a cross-sectional view illustrating a method of manufacturing a general photoresist pattern.

2A to 2C are cross-sectional views of respective processes for explaining a method of manufacturing a photoresist pattern having a fine spacing according to the present invention.

The present invention relates to a method of manufacturing a photoresist pattern, and more particularly, to a method of manufacturing a photoresist pattern having a fine interval or line width.

In general, a semiconductor device is composed of a plurality of circuit patterns. The plurality of circuit patterns are defined by using a photoresist pattern obtained by a photolithography process as a mask. The photolithography process, as is known, includes a series of processes of applying, exposing and developing the photoresist film, and in particular, the line width and spacing of the photoresist pattern are determined by the exposure process.

At present, as semiconductor devices have increased integration degree, circuit patterns having finer line widths and spacings are required. In order to fabricate circuit patterns having such fine line widths and spacings, that is, photoresist patterns for defining circuit patterns, There is a need for photolithographic techniques.

A method of manufacturing a photoresist pattern by a general photolithography method is shown in FIG. 1.

A photoresist film is applied onto the semiconductor substrate 10. The reticle 20 for defining a circuit pattern on the semiconductor substrate 10 to which the photoresist film is applied is spaced apart from the semiconductor substrate 10 at a predetermined distance. The portion labeled reticle 20 in FIG. 1 substantially represents the blocking pattern of the reticle. Thereafter, the photoresist film on the semiconductor substrate 10 is exposed. Reference numeral 30 denotes light. Then, the photoresist film is selectively exposed by the reticle 20.

However, as the interval between the photoresist patterns required by the highly integrated semiconductor device currently closes to the limit value of the exposure source, the optical intensity passing through the reticle 20 can be resolved in the photoresist film even when the exposure process is performed normally. Lower. For this reason, there is a problem that the photoresist film is not removed in spite of exposure, so that the gap between the photoresist patterns is not secured.

Thus, in order to secure fine spacing by another conventional method, a method of reflowing a photoresist pattern and a method of using a phase reversal mask have been proposed.

The reflow method of the photoresist pattern is a method of reducing the gap between the photoresist patterns by heat-treating the photoresist pattern at a predetermined temperature to flow sideways.

In addition, the phase inversion mask is a method of setting the space | interval of a photoresist pattern by the boundary part of a 0 degree phase region and a 180 degree phase region etc. as it is known.

However, the reflow method of the photoresist pattern has a problem that the reproducibility is poor because the interval of the photoresist pattern is suddenly changed in accordance with the change of the heat treatment process. In addition, the method using the phase inversion mask has a disadvantage that the phase inversion mask itself is expensive and difficult to manufacture.

Accordingly, it is an object of the present invention to provide a method of manufacturing a photoresist pattern having a fine spacing or line width which is excellent in reproducibility while using a binary reticle.

In order to achieve the above object of the present invention, the present invention includes the step of applying a photoresist film on a semiconductor substrate. Next, a first reticle is disposed so that the first region of the photoresist film is exposed, and the first region of the exposed photoresist film is irradiated with light having an intensity less than or equal to resolvable intensity. Thereafter, the first reticle is removed and a second reticle is placed so that a portion of the first region and the second region are exposed. Thereafter, the exposed first and second regions are irradiated with light having an intensity less than the resolution that can be resolved, and then the photoresist film is developed to remove portions irradiated with light to form a photoresist pattern. do.

The photoresist film may be formed of a positive type or a negative type photoresist.

When the photoresist film is formed of a positive type photoresist, the interval of the photoresist pattern is determined by the width of the overlapping portion of the first region exposed by both the first and second reticles.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

2A to 2C are cross-sectional views of respective processes for explaining a method of manufacturing a photoresist pattern having a fine spacing according to the present invention.

First, referring to FIG. 2A, a photoresist film 150 is coated on the semiconductor substrate 100 having an etched layer (not shown). For example, a positive type photoresist film is used as the photoresist film 150, and the photoresist film 150 is formed by spin coating. Next, the first reticle 110 is disposed on the resultant of the semiconductor substrate 100 to which the photoresist film 150 is applied. The first reticle 110 includes a quartz substrate 111 and a pattern 115 disposed on the quartz substrate 111 and opaque to exposure light. The first reticle 110 is aligned such that the opaque pattern 115 may expose the first region 105-1 of the photoresist film 150. Thereafter, light 120 is irradiated to the resultant of the semiconductor substrate 100. At this time, the intensity of the irradiated light should be smaller than the threshold value of the resolvable intensity of the photoresist film 150.

Thereafter, referring to FIG. 2B, the first reticle 110 is removed. Thereafter, the second reticle 130 is disposed to expose the second region 105-2. The second reticle 130 is composed of a quartz substrate 131 and an opaque pattern 135 with respect to exposure light disposed on the quartz substrate 131, like the first reticle 110. That is, the second region 105-2 is exposed by the opaque pattern 135 of the second reticle 130. In the present embodiment, the opaque pattern 135 of the second reticle 130 may not only have a portion of the first region 105-1 contacting the second region 105-2 but also the second region 105-2. Expose Next, light 120 is irradiated to portions of the exposed second region 105-2 and the first region 105-1. The light should also be set so that the intensity is smaller than the threshold of the resolutionable intensity of the photoresist film 150. A portion 105-3 (hereinafter overlapped) of the first region exposed by the opaque pattern 135 of the second reticle 130 is double exposed, which is the spacing of the photoresist pattern to be formed later. The line width of the overlapping portion 105-3 can be arbitrarily adjusted by the arrangement of the second reticle 130.

Next, as shown in FIG. 2C, the photoresist film 105 is developed. Then, only the portion of the photoresist film corresponding to the overlapping portion 105-3 is selectively removed to define the photoresist pattern 150 having a fine spacing.

That is, since the overlapping portion 105-3 of the first region 105-1 and the second region 105-2 has been double-exposed by light having resolution less than the intensity, the intensity is amplified so that the double exposure can be achieved. This part is removed by the developer. As a result, a photoresist pattern having minute spacing can be produced. On the other hand, since the other part was exposed once by the light which has intensity | strength below resolution resolvable intensity | strength, it is not removed by image development and becomes a photoresist pattern.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. .

As described in detail above, according to the present invention, the photoresist film is selectively exposed two times with an intensity that cannot be resolved, and the portions to be spaced between the photoresist patterns are exposed twice. Thereafter, when the development process is performed, only the portions subjected to the two exposures are selectively removed to produce a photoresist pattern having a fine interval.

Of course, according to the method described above, a photoresist pattern having a fine width can also be produced.

Since the present invention can arbitrarily adjust the spacing or pattern width of the photoresist pattern only by arranging the reticle, it is excellent in reproducibility and can be manufactured by a binary mask (reticle), so that a phase inversion mask requiring an expensive and complicated process is required. You do not need to use it.

Claims (3)

Applying a photoresist film on the semiconductor substrate; Disposing a first reticle to expose the first region of the photoresist film; Irradiating light having an intensity less than resolvable intensity to a first region of the exposed photoresist film; Removing the first reticle; Disposing a second reticle such that a portion of the first region and a second region are exposed; Irradiating light having an intensity less than resolvable intensity to a portion of the exposed first region and a second region; And Developing the photoresist film to remove overlapping portions irradiated with light or portions not irradiated with light to form photoresist patterns having a fine interval or a fine width. The method of claim 1, And the photoresist film is a positive type photoresist pattern. The method of claim 1, The gap or width of the photoresist pattern is determined by the width of the overlapping portion of the first region exposed by both the first and second reticle.

Images