KR20080001439A - Method for manufacturing photo-mask by using layout design correction - Google Patents

Abstract

A method for manufacturing a photo mask by using a layout design correction method is provided to suppress pattern errors caused by a pattern density difference between layout patterns of the photo mask by adding a dummy pattern to a low-density region of layout pattern data. A pattern density comparison process is performed to compare layout pattern data of a photo mask with each other in order to detect a pattern density difference(S20). A determination process is performed to determine whether a low-density pattern space is included in the layout pattern data(S30). A data correction process is performed to correct the layout pattern data by adding dummy pattern data to the low-density pattern space when the low-density pattern space is included in the layout pattern data(S40). The photo mask is manufactured by using the corrected layout pattern data(S50).

Description

Method for manufacturing photo-mask by using layout design correction}

1 is a view showing the layout of a photomask according to the prior art.

2 is a view showing a region in which a pattern is not formed by a low density space region on the layout when the pattern is formed using the layout of the photomask according to the prior art.

3 is a flowchart sequentially illustrating a method of manufacturing a photomask using layout design modification according to the present invention.

4 is a diagram illustrating a layout of a photomask in which a layout design is modified according to the present invention.

<Explanation of symbols for the main parts of the drawings>

a: low density region without pattern

b: area where a pattern is formed

c: area where no pattern is formed

10: dummy pattern added to the low density space region

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a photomask used in a photolithography manufacturing process, and more particularly, to a method of manufacturing a photomask that can prevent a defect of a photomask pattern by modifying a pattern layout design.

In general, photolithography technology is a basic technology leading to high integration of semiconductor devices, and forms a pattern on a semiconductor substrate using light. That is, by irradiating light of exposure equipment such as ultraviolet rays, electron beams, or X-rays to a position where a pattern such as an insulating film or a conductive film should be formed on a semiconductor substrate, a photoresist whose solubility is changed is formed, After exposing a predetermined portion of the resist to light, a photoresist pattern is formed by removing a portion having high solubility with respect to the developer. A portion exposed by the photoresist pattern is removed by an etching process to form a desired semiconductor device pattern.

As the integration of semiconductor devices increases, irregularities in patterns that are commonly found in logic devices such as microprocessors are decreasing in both depth of focus and resolution. In order to overcome this problem, when a pattern having a numerical value close to a resolution limit is formed, an optical proximity effect occurs in which a design pattern and a pattern actually formed on a semiconductor substrate are separated from each other. The performance of the device is significantly deteriorated compared to the design due to the difference between the design and the actual pattern. Accordingly, the correction of the optical distortion correction (OPC) of the pattern occurring at the resolution limit in the photolithography process is now an inevitable technique. By such OPC technology, the fine pattern of the photo mask can be faithfully completed as designed on the semiconductor substrate which is a wafer.

1 is a view showing the layout of a photomask according to the prior art.

Referring to FIG. 1, in the conventional method of manufacturing a photomask, an OPC is performed in consideration of a target layout of a photomask, an OPC data pattern is exposed to a substrate through an exposure process, and an exposed part is removed using a development process. The photoresist pattern is formed by removing the portion having high solubility with respect to the developer of the photomask. The portion exposed by the photoresist pattern is removed by an etching process to form a pattern of the photo mask.

2 is a view showing a region in which a pattern is not formed by a low density space region on the layout when the pattern is formed using the layout of the photomask according to the prior art.

Since the OPC process of the photo mask is to match the correction amount of the photo mask pattern to the set target, if the target including the layout pattern density is set incorrectly at the layout design stage, the desired pattern cannot be accurately obtained only by the OPC.

That is, the pattern correction by the OPC can correct the size of the patterns by the influence of the design pattern density of the photomask, that is, the density difference between the low density region without a pattern (see a in FIG. 1) and the high density region with many patterns. have. As shown in FIG. 2, even when pattern correction of the OPC is performed, the pattern is formed in a region having a high pattern density in the photomask patterning process, but the pattern is not formed well in a region having a low pattern density. (c)

Therefore, in the photomask manufacturing method according to the prior art, if the target including the layout pattern density difference of the photomask is set incorrectly, the desired pattern cannot be accurately produced only by pattern correction by OPC.

An object of the present invention is to solve the problems of the prior art, by designing and adding a dummy pattern to the low density region when there is a low density space region in the layout pattern data of the photo mask, due to the difference in the density of the layout pattern of the photo mask The present invention provides a method of manufacturing a photomask using layout design modification that can prevent a pattern manufacturing defect.

In order to achieve the above object, the present invention provides a method of manufacturing a photomask, comprising the steps of comparing the pattern density in the layout pattern data of the photomask, determining whether there is a low density pattern space in the layout pattern data, and determining As a result, when the low density pattern space exists, modifying the layout pattern data by adding dummy pattern data to the low density pattern space region, and manufacturing a photomask on the substrate using the modified layout pattern data.

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

3 is a flowchart sequentially illustrating a method of manufacturing a photomask using layout design modification according to the present invention.

As shown in Fig. 3, the photomask manufacturing method using the layout design modification according to the present invention proceeds as follows.

First, the present invention receives layout pattern data, which is a design pattern of a semiconductor element of a photomask. (S10)

The pattern densities of the semiconductor elements present in the input layout pattern data are compared (S20).

In the layout pattern data, it is determined whether a low density pattern space area having a predetermined space area between patterns exists (S30).

As a result of the determination in S30, when the preset low density space region exists in the layout pattern data, the dummy pattern (10e of FIG. 4) is added to the low density pattern space region in the layout pattern data to correct the layout pattern data of the photomask. To modify layout pattern data using a dummy pattern, add a dummy pattern to the layout pattern data using a general rule file (Hercules, Caliber) or a manual. For example, the low density pattern space region may be formed in the core region or the peripheral circuit region. The dummy pattern may be added between the word line, the bit line, the isolation region, and the metal wiring.

After operation S40, the optical proximity effect correction (OPC) process is performed on the modified layout pattern data to correct the optical proximity effect of the pattern.

The photomask is manufactured on the substrate by performing exposure and development processes using layout pattern data (including dummy patterns in the low density pattern space region) in which the optical proximity effect is corrected (OPC) (S50).

If it is determined in S30 that there is no predetermined low density spatial region in the layout pattern data, the optical proximity effect correction (OPC) process is performed on the layout pattern data which is the original design pattern of the photomask to correct the optical proximity effect of the pattern. .

Next, an exposure and development process is performed using layout pattern data, which is an original design pattern with the optical proximity effect corrected (OPC), to manufacture a photomask on the substrate.

4 is a diagram illustrating a layout of a photomask in which a layout design is modified according to the present invention.

As shown in FIG. 4, the present invention adds a dummy pattern 10e to the low density pattern space region in the layout pattern data when a low density space region having a predetermined range exists in the layout pattern data which is the original design pattern of the photo mask. do.

That is, the present invention does not perform an optical proximity effect correction (OPC) process immediately after adding a dummy pattern to the low density spatial region of the layout pattern data even if a low density pattern spatial region exists in the originally designed layout pattern data of the photo mask. Proximity effect correction process is performed.

Accordingly, the present invention can accurately pattern the pattern of the photo mask by correcting the photo mask pattern defect caused by the difference in layout pattern density of the photo mask in the designed layout pattern data.

On the other hand, the present invention is not limited to the above-described embodiment, various modifications are possible by those skilled in the art within the spirit and scope of the present invention described in the claims to be described later.

As described above, when the low density space region exists in the layout pattern data, which is the original design of the photo mask, the present invention modifies the layout design by adding a dummy pattern to the low density space region so that the density difference of the layout pattern of the semiconductor device for the photo mask is improved. It is possible to prevent the defects in pattern production due to this, and the semiconductor manufacturing yield can be greatly improved.

Claims (3)

In the method of manufacturing a photo mask, Comparing pattern densities in layout pattern data of the photo masks; Determining whether a low density pattern space exists in the layout pattern data; Modifying layout pattern data by adding dummy pattern data to the low density pattern space region when the low density pattern space exists as a result of the determination; And, And manufacturing the photomask on the substrate with the modified layout pattern data. The method of claim 1, The method, And if the low density pattern space does not exist, manufacturing the photo mask on the substrate using the layout pattern data. The method according to any one of claims 1 and 2, The method, And prior to the manufacturing of the photo mask, correcting the optical proximity effect of the pattern by performing OPC of the layout pattern data.

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