KR980011700A - Focus management method in photolithography process - Google Patents

Abstract

A focus management method according to the present invention includes the steps of adding a focus confirmation pattern to a predetermined position in a photomask used for a photolithography process for manufacturing a semiconductor, Confirming a cross-sectional profile and a planar shape of an actual pattern formed on the wafer by the photomask, and correcting the leveling according to the result. According to the present invention, focus in an optical field can be efficiently managed in a photolithography process for semiconductor fabrication.

Description

Focus management method in photolithography process

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The present invention relates to a focus management method in a photolithography process, and more particularly to a focus management method for separately forming a pattern for confirming a profile and a shape of a pattern in a mask or a reticle.

As high capacity of semiconductor products is required, high integration has been achieved, but it has not yet reached satisfactory level. Therefore, the size of the product, that is, the chip size, gradually increases, and accordingly, the required optical field size of the exposure equipment is also increasing.

In the photolithography process in the semiconductor manufacturing process, it is necessary to manage various conditions in the optical field uniformly. However, since the optical field size gradually increases, it becomes increasingly difficult to manage various conditions in the optical field to be uniform. Particularly, the influence of the uniformity of the focus in the field on the patterning and CD (Critcal Diminsion) is very large. Further, as the semiconductor device is required to be highly integrated, the design rule becomes more severe and the focus margin in the photolithography process becomes more insufficient It is becoming. Therefore, it is necessary to specifically manage the focus uniformity.

Up to now, CD and pattern profiles have been inspected using an SEM or the like to manage the focus uniformity in the optical field. However, such a method is difficult to grasp in the complex hole pattern.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a focus management method capable of improving focus uniformity by effectively managing focus in a field of culture in a photolithography process for manufacturing semiconductors.

FIG. 1 is a view showing a photomask used for carrying out the method of the present invention in a photolithography process for semiconductor fabrication.

FIG. 2 is a view showing the position of the focus confirmation pattern in the optical field. FIG.

FIGS. 3 to 5 are views showing a cross-sectional profile and a planar shape of an actual pattern formed on the aperator by the photomask of FIG.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, including: attaching a focus confirmation pattern to a predetermined position in a photomask used for a photolithography process for manufacturing a semiconductor; And correcting the leveling in accordance with the result of the check. The focus management method of the present invention includes the steps of:

Preferably, the predetermined position in the photomask in the step of adding the focus confirmation pattern is at least one of a center portion in a culture field and a corner portion in all directions or two or more portions.

Also, preferably, in the step of adding the focus confirmation pattern, the focus confirmation pattern may be formed of a line-and-space pattern, an island pattern, or a contact hole pattern .

According to the present invention, focus in an optical field can be efficiently managed in a photolithography process for semiconductor fabrication.

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

A focus management method according to a preferred embodiment of the photolithography process for manufacturing a semiconductor will be described with reference to FIGS. 1 to 3. FIG.

1 is a view for explaining a step of adding a focus confirmation pattern to a predetermined position in a photomask used for a photolithography process for semiconductor fabrication. In Fig. 1, (a) is a cross-sectional view of a photomask used in the method of the present invention, and (b) is a plan view thereof.

1 (a) and 1 (b), in order to manufacture a photomask for carrying out the method of the present invention, a photomask in which a light-shielding film pattern 12 is formed by a chromium film is formed on a transparent substrate 10 .

As shown in FIG. 1 (b), the sizes and pitches in which the contact hole patterns are formed are arranged in various sizes, and they can be distinguished according to the exposure energy.

The focus confirmation pattern may be formed of a line-and-space pattern, an island pattern, or the like in addition to the contact hole pattern.

Fig. 2 is a view for explaining the position in the optical field of the focus confirmation pattern formed in the photomask. Fig. 2, the focus confirmation pattern formed by the light-shielding film pattern 12 on the transparent substrate 10 preferably has a center portion (a) in the optical field, a corner portion (b) to (e).

FIGS. 3 to 5 are diagrams for explaining a step of confirming a cross-sectional profile and a planar shape of an actual pattern formed on a wafer by the photomask, wherein a pattern as shown in FIG. 1B is formed on a wafer .

FIG. 3 shows the case of defocusing in the negative direction, FIG. 4 shows the case of normal focus, FIG. 5 shows the case of defocusing in the positive direction, Profile, angle (b) shows its plan view.

Thereafter, according to the confirmation result, the focus difference in the optical field is digitized to correct the leveling. The focus uniformity can be improved by such a method.

As described above, according to the present invention, focus in an optical field can be efficiently managed in a photolithography process for manufacturing a semiconductor.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but variations and modifications may be made by those skilled in the art within the technical scope of the present invention. It is possible.

Claims (3)

Comprising the steps of: adding a focus confirmation pattern to a predetermined position in a photomask used in a photolithography process for semiconductor fabrication; confirming a cross-sectional profile and a planar shape of an actual pattern formed on the wafer by the photomask; And correcting the leveling in accordance with the result of the determination. The photomask of claim 1, wherein the predetermined position in the photomask in the step of adding the focus confirmation pattern is a portion of at least one of a center portion in an optical field and an upper corner portion. A focus management method in a process. The method according to claim 1, wherein in the step of adding the pattern for confirming fraudulent focus, the focus confirmation pattern is a line space pattern, an island pattern, or a contact hole pattern Wherein the focus control method is a photolithography process. ※ Note: It is disclosed by the contents of the first application.