KR19990039999A - Method for Correcting Proximity Effects in Exposure Systems - Google Patents

Abstract

The exposure system deforms the cross-sectional shape of the electron beam generated and transmitted from the beam source portion for generating the adjusted electron beam to form integrated circuit patterns on a target such as a wafer or photomask located in the target area. To this end, the first beam deformable part including the first aperture and the second beam deformable part including the second aperture are included. Meanwhile, the method for correcting the proximity effect in the exposure system includes an exposure process by adding a correction pattern, such as a serif, to the existing pattern in the pattern design step of the semiconductor device to compensate for the proximity effect generated during exposure. Do this. On the other hand, the second aperture formed in the second beam deformed portion is formed in the same shape as the correction pattern region when the design data of the pattern is divided. The exposure process is performed by matching the design data of the pattern with the shape corresponding to the second apertures.

Description

METHOD OF COMPENSATING THE PROXIMITY EFFECT IN ELECTRON BEAM EXPOSURE SYSTEMS

The present invention relates to a method for correcting a proximity effect in an exposure system, and more particularly, to a proximity effect in an exposure system for correcting a proximity effect generated when a pattern is formed on a wafer in an exposure system of a semiconductor manufacturing system. It relates to a method for correcting.

Recently, semiconductor devices have increased in fine and complex patterns. Electron exposure systems to which an electron beam having various cross-sectional shapes are applied have been developed for the purpose of forming patterns of such fine and complex semiconductor devices. In one example, Journal of Vacuum Science and Technology B 2 (6) Jan./Feb. 1988, p209-212, "The electron-beam column for a high dose and high-voltage electron-beam exposure system EX-7," describes one of the representative exposure systems currently in use.

In such exposure systems, a method of exposing an image of an electron beam generated from a beam source unit to a shape and size to be exposed using a beam deformation unit having a predetermined shape on a plate is used to expose the wafer on a wafer. The exposure systems further include a beam source portion for generating an adjusted electron beam to form integrated circuit patterns on a target located in a target area and the electron beam is transmitted from the beam source portion to the target region. It consists of an electron beam transmission part forming a path as much as possible. In this case, the electron beam transmission part may include a first beam deformation part having a first aperture and a second beam having a second aperture formed in order to modify a cross-sectional shape of the electron beam generated and transmitted from the beam source part. The lens unit and the deflector unit are configured to transmit an image of the electron beam generated from the deformer and the beam source unit to the target area via the first and second beam deformers.

Meanwhile, the image of the electron beam to be exposed to the target is an image synthesized by the combination of the first and second apertures. That is, the image of the electron beam generated from the beam source portion is firstly deformed by the first aperture of the first beam deformable portion, and then secondly deformed secondly by the second aperture of the second beam deformable portion. And exposed to the target. The lens unit and the deflector unit adjust the flow density of the electron beam and maintain the uniformity so that the lens unit and the deflector unit are transmitted from the beam source unit to the target region through the first and second beam deformation units.

Meanwhile, in the production field of integrated circuits, efforts are being made to reduce manufacturing costs and improve work speeds in order to cope with a continuous reduction in size of integrated circuits. However, circuit lines with line widths of less than one micrometer can no longer cope with such means as current photolithographic methods. Of course, as described above, although higher resolutions are generally allowed in the exposure of the patterns by lithographic processes employing an electro-beam, the actual exposure of the (photoresist) layer and substrate There is a significant problem with the scattering effects of electrons in unstable radiation. This negative effect is called the proximity effect.

Due to this problem, as the degree of integration of semiconductor devices increases, the quality and pattern accuracy of photomasks used in photolithography processes become important. When it is impossible to form or form a pattern or a pattern on a photomask due to the limitation of a stepper or the like, a problem occurs in terms of pattern fidelity as shown in FIGS. 1A and 1B. That is, when the pattern 100 as shown in FIG. 1A is exposed on the wafer, the corners U, V, W, X, Y, and Z on the pattern 100 may be exposed to the wafer as shown in FIG. 1B. In the pattern 100 'exposed and formed on the edges, the corners U', V ', W', X ', Y', and Z 'are rounded by the above-described proximity effect. In addition, the phenomenon in which each corner is deformed is further deteriorated when a fine pattern is formed, which causes a problem in that a pattern intended for design cannot be formed on a wafer.

In order to compensate for the proximity effect, a pattern correction step such as a serif is added to an existing pattern in the pattern designing step of the semiconductor device to improve pattern thinness.

However, in such a case, automatic layout software is required to form serifs, a system for processing a large amount of design data for forming this serif on a photo mask, and a time for processing the data Is approaching the limit. Therefore, such a problem adds to the seriousness of the problem as the semiconductor device becomes highly integrated.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and its object is to enable data processing at the same difficulty level as that of a general exposure method when applying a correction pattern in order to prevent the proximity effect of a pattern in an exposure system. It is to provide a method for correcting the proximity effect in a new type of exposure system that can minimize the capacity of the data when forming the pattern.

1A and 1B are diagrams for explaining a proximity effect occurring in a conventional exposure system,

2 is a diagram illustrating an exposure system to which a method for correcting proximity effect is applied in an exposure system according to an embodiment of the present invention;

3 is a diagram illustrating a pattern to which a correction pattern is added to explain a method for correcting a proximity effect in an exposure system according to an embodiment of the present invention;

4 is a diagram illustrating a method of dividing the pattern of FIG. 3 by applying a method for correcting a proximity effect in an exposure system of the present invention;

5 is a plan view showing an embodiment of a second beam deformer for applying a method for correcting a proximity effect in an exposure system of the present invention;

FIG. 6A is a second diagram illustrating a method of exposing the “A” portion in the pattern of FIG. 3 in combination with the first beam deformable portion of the embodiment to which the method for correcting the proximity effect in the exposure system of the present invention is applied; FIG. Top view of the beam deformation part,

6B is a diagram showing a pattern exposed on a target by FIG. 6A;

FIG. 7A is a plan view illustrating a method of exposing a “B” part in a pattern of FIG. 3 by combining a second beam deformation part with a first beam deformation part according to an exemplary embodiment of the present disclosure; FIG.

7B is a diagram showing a pattern exposed on a target by FIG. 7A;

8A is a plan view illustrating a method of exposing a "C" part in the pattern of FIG. 3 by combining a second beam deforming part with a first beam deforming part according to an exemplary embodiment of the present invention;

8B is a diagram showing a pattern exposed on a target by FIG. 8A;

FIG. 9A is a plan view of a second beam deformable part illustrating a method of exposing a “D” part in a pattern of FIG. 3 by combining a second beam deformable part with a first beam deformable part according to an embodiment of the present invention; FIG.

9B is a diagram showing a pattern exposed on a target by FIG. 9A;

FIG. 10A is a plan view of a second beam deformable part illustrating a method of exposing an “E” part in the pattern of FIG. 3 by combining a second beam deformable part with a first beam deformable part according to an embodiment of the present disclosure; FIG.

10B is a diagram showing a pattern exposed on a target by FIG. 10A;

11A and 11B are diagrams for describing a state in which a pattern is exposed to a target by a method for correcting a proximity effect in an exposure system according to an exemplary embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

10 beam source portion 12 first beam deformation portion

14: first aperture 16: second beam deformable portion

18: The 2nd Aperture 18-1: The 2nd Aperture

18-2: 2-2 Aperture 18-3: 2-3 Aperture

18-4: 2-4 Aperture 19-1: Main Aperture

19-1 ': Sub aperture 20: Target

22: pattern 24: correction pattern

26: target pattern

According to a feature of the present invention for achieving the above object, generated from the beam source portion and the beam source portion for generating an adjusted electron beam to form integrated circuit patterns on the target located in the target area (target area) In an exposure system including a first beam deformation portion having a first aperture and a second beam deformation portion having a second aperture in order to modify the cross-sectional shape of the electron beam to be transmitted, a proximity effect When the exposure process is performed by adding a correction pattern such as a serif to the existing pattern in the pattern designing step of the semiconductor device, a method for correcting the proximity effect in the exposure system may include: A second aperture capable of realizing the shape of the correction pattern is configured, and a predetermined correction pattern added to the existing pattern is exposed.

In the present invention as described above, the target is a photomask. The target is a wafer. A photomask for forming an image of a pattern exposed on the wafer is a photomask formed by the above method. The second aperture has the same shape and includes at least one aperture of different dimensions. The same beam as the first aperture of the first beam deformable portion is formed in the second beam deformable portion. One of the second apertures is selected and the dose is varied upon exposure in the exposure system and exposed on the target.

According to another aspect of the present invention for achieving the above object, from the beam source portion and the beam source portion for generating an adjusted electron beam to form integrated circuit patterns on the target located in the target area (target area) In an exposure system including a first beam deformer having a first aperture and a second beam deformer having a second aperture to modify the cross-sectional shape of the generated and transmitted electron beam, a proximity effect In the pattern design step of the semiconductor device, when the exposure process is performed by adding a correction pattern such as a serif to the existing pattern, a method for correcting the proximity effect in the exposure system is described. A sub-array of a predetermined size so as to communicate with the main aperture at each vertex of the main aperture formed in a rectangular shape of a predetermined size; A square having a predetermined size so as to form at least one 2-1 aperture having a chur and equal to one side shape of the 2-1 aperture based on a vertical or horizontal centerline of the 2-1 aperture Forming at least one second-2 aperture formed by a surface extending inwardly from one side of the upper aperture formed in the shape, and facing the second aperture in the second-2 aperture At least one second to third aperture is formed in the same manner as the second to second aperture in the shape of the other one side of the second to first aperture that is not formed, and the correction pattern is defined as the second to first. It is formed in accordance with the second to third apertures, and is exposed in correspondence with a second aperture having the same shape among the second apertures during exposure.

In the present invention as described above, the sub-aperture has a rectangular shape, and a vertex of the sub-aperture communicating with the main aperture is located on the main aperture. The second aperture has the same shape and includes at least one aperture of different dimensions. The same beam as the first aperture of the first beam deformable portion is formed in the second beam deformable portion. One of the second apertures is selected and the dose is varied upon exposure in the exposure system and exposed on the target.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 2 through 11B, and like reference numerals denote like elements for performing the same function.

It is an object of the present invention to provide a method for correcting the proximity effect that occurs when a pattern is formed on a wafer or photomask during a semiconductor manufacturing process. In this case, as shown in FIG. 2, the exposure system includes a beam for generating an adjusted electron beam to form integrated circuit patterns on a target 20 such as a wafer or photomask located in a target area. First beam deforming part 12 and second in which a first aperture 14 is formed to modify a cross-sectional shape of the source part 10 and the electron beam generated and transmitted from the beam source part 10. It is comprised including the 2nd beam deformation | transformation part 16 in which the aperture 18 was formed. In addition, the exposure system includes a lens unit for transmitting an image of the electron beam generated from the beam source unit 10 to the target area via the first and second beam deforming units 12 and 16. And deflector are included.

Meanwhile, the method for correcting the proximity effect in the exposure system of the present invention adds a correction pattern such as a serif to the existing pattern in the pattern design step of the semiconductor device to compensate for the proximity effect generated during exposure. To be applied when performing an exposure process.

3 is a diagram illustrating a pattern to which a correction pattern is added to explain a method for correcting a proximity effect in an exposure system according to an exemplary embodiment of the present invention, and FIG. 4 is a diagram illustrating a method of correcting a proximity effect in an exposure system of the present invention. 3 is a diagram illustrating a method of dividing the pattern of FIG.

As shown in FIG. 3, in order to perform an exposure process, correction patterns 24 are formed on a pattern 22 exposed to a target such as a wafer or a photomask. As such, the pattern 22 in which the correction patterns 24 are formed divides portions having the same shape into one group for exposure in the exposure system, as shown in FIG. 4. That is, referring to FIG. 4, the pattern 22 on which the correction patterns 24 are formed may be divided into pattern areas of “A” to “F”. In this case, the "A" to "E" pattern regions are regions where a correction pattern is formed, and the "E" pattern regions are regions where a correction pattern is not formed. In this case, the general pattern area F is an area that can be performed in a general exposure system, but the correction pattern areas A through E increase the number of data when performing in a general exposure system, thereby increasing data processing speed and exposure. The problem that the execution speed is lowered.

In order to overcome this problem, the method for correcting the proximity effect in the exposure system of the present invention is to form at least one second aperture in the second beam deformation portion of the exposure system in the same shape as the shape of the correction pattern, When exposing a predetermined correction pattern added to an existing pattern, the second aperture is exposed to correspond to a second aperture having the same shape among the second apertures.

5 is a plan view of a second beam deformable part showing a second beam deformable part of the embodiment to which the method for correcting the proximity effect in the exposure system of the present invention is applied.

3 to 5, the second apertures 18-1, 18-1 ′, 18-2, 18-2 ′, 18-3, 18-formed in the second beam deforming part 16 are illustrated. 3 'and 18-4 are apertures for exposing the pattern 22 shown in FIG. 3 on the target in combination with the first aperture of the first beam deformation portion. In this case, the 2-1 aperture 18- among the second apertures 18-1, 18-1 ', 18-2, 18-2', 18-3, 18-3 ', and 18-4. 1), 2-2 aperture 18-2, and 2-3 aperture 18-3 are areas in which the correction pattern 24 is formed in the pattern 22, that is, the correction pattern region of FIG. These are apertures formed for exposing the holes A, B, C, D, and E. The 2-1 aperture 18-1, the 2-2 aperture 18-2, and the 2-3 aperture 18-3 are the correction pattern regions A, B, C, D, and E) so as to correspond respectively. In the second beam deformable part 16, the second-4 aperture 18-4 is an aperture formed to expose the general pattern region F of FIG. 4, and the first upper of the first beam deformed part 16. It is possible to form with an upper of the same shape as the chur.

As described above, the method for correcting the proximity effect in the exposure system according to the exemplary embodiment of the present invention includes the shape of the correction pattern region in which the shape of the second aperture formed in the second beam deformation part of the exposure system is formed in the pattern to be exposed. It is formed to be the same as, and is exposed to the target by fitting an aperture of the same shape as the correction pattern region to be exposed.

On the other hand, when the exposure process is performed by matching the shape of the second aperture with the correction pattern region in this way, one of the second apertures is selected, and a dose is changed during exposure in the exposure system to change the target. It can provide an advantage that can be exposed on the image.

Meanwhile, referring to FIG. 5, various apertures having the same shape and different dimensions may be formed in the second beam deformation unit 16 according to the exemplary embodiment of the present invention. That is, the same as the above-mentioned 2-1 aperture 18-1, 2-2 aperture 18-2, and 2-3 aperture 18-3, respectively, It is possible to form different apertures 18-1 ', 18-2', 18-3 '. By forming the apertures 18-1 ', 18-2', and 18-3 ', the pattern is exposed to the target while preventing the proximity effect as much as possible when exposing patterns having the same shape but different sizes. It can be. In addition, if the photomask is fabricated using a method for correcting the proximity effect in the exposure system of the present invention, and the photomask is used together with the method for correcting the proximity effect in the exposure system of the present invention upon exposure to a wafer, The exposure effect will be maximized.

Referring again to FIG. 5, the second aperture has a sub-aperture of a predetermined size to communicate with the main aperture 19-1 at each vertex of the main aperture 19-1 formed in a rectangular shape having a predetermined size. At least one 2-1 aperture 18-1 having (19-1 ') and said second reference based on a vertical or horizontal centerline S of said 2-1 aperture 18-1; 2-1 at least formed of a surface 19-2 ′ extending inwardly from one side of the aperture 19-2 formed in a rectangular shape having a predetermined size to be the same as one side of the aperture 18-1. The second second aperture 18-2 and the second second aperture 18-2 that is not formed in the second-2 aperture 18-2 in a form opposite to the second second aperture 18-2. The shape of the remaining one side of the 2-1 aperture 18-1 is composed of at least one 2-3 aperture 18-3 in the same manner as the 2-2 aperture 18-2. . Of course, the method for correcting the proximity effect in the exposure system of the present invention is that the shape of the second aperture formed in the second beam deformation portion is formed to be the same as the shape of the correction pattern region formed in the pattern to be exposed. As described above, it will be appreciated that the second beam deformation portion in which the second aperture is formed may be used when forming various types of patterns. In this case, the sub-aperture 19-1 ′ of the 2-1 aperture 18-1 may have various shapes. The sub-aperture 19-1 ′ may have various shapes. One vertex in communication with the aperture 19-1 is located on the main aperture 19-1.

The second beam deformation portion to which the second aperture is applied according to the embodiment of the present invention is combined with the first beam deformation portion on which the first aperture is formed to expose the designed pattern to a target such as a wafer or a photomask. To change the image of the electron beam. Accordingly, a method of combining according to design data in the method for correcting the proximity effect in the exposure system according to the embodiment of the present invention will be described in detail with reference to FIGS. 6A to 10B.

FIG. 6A is a second diagram illustrating a method of exposing the “A” portion in the pattern of FIG. 3 in combination with the first beam deformable portion of the embodiment to which the method for correcting the proximity effect in the exposure system of the present invention is applied; FIG. Fig. 6B is a diagram showing a pattern exposed on the target by Fig. 6A.

Referring to FIGS. 6A and 6B together with FIGS. 2 to 4, as described above, FIG. 3 and the pattern 22 for exposing to a target may be divided as shown in FIG. 4. At this time, the first aperture 14 of the first beam deformable portion 12 and the second aperture 18 of the second beam deformable portion 16 are exposed to expose the “A” region, which is one of the correction pattern regions. Need to be combined. Thus, the area "A" is formed by the combination of one edge of the 2-1 aperture 18-1 and the first aperture 14. In this manner, as illustrated in FIG. 6B, the "A" region is exposed to a target such as a wafer or a photomask to form a pattern.

When the exposure of the area "A" is completed as described above, the exposure system performs a second operation of the first aperture 14 and the second beam deformation unit 16 of the first beam deformation unit 12 to expose the next area. The aperture 18 is reset. 7A and 7B, the exposure system exposes the first aperture 14 and the second-first aperture 18-1 to expose the “B” region on the pattern 22. Will be combined. On the other hand, since the "B" region is composed of two on the pattern 22, the two "B" regions in the state in which the first aperture 14 and the 2-1 aperture 18-1 are combined. Is exposed to the target.

As described above, according to the method for correcting the proximity effect in the exposure system of the present invention, the pattern 22 having the correction pattern 24 is formed as shown in FIG. 3. In this case, the second aperture 18 is formed in the second beam deforming unit 16 as described above. In addition, the pattern 22 is exposed by combining the first aperture 14 of the first beam deformation unit 12 and the second aperture 18 of the second beam deformation unit 16.

8A to 10B, the pattern 22 is sequentially exposed to the target using a method for correcting the proximity effect in the exposure system of the present invention. In this case, the exposure order as described above is for explaining a method of associating the design data of the pattern with the second aperture in the method for correcting the proximity effect in the exposure system of the present invention. You will see that it is the same.

11A and 11B are diagrams for describing a state in which a pattern is exposed to a target by a method for correcting a proximity effect in an exposure system according to an exemplary embodiment of the present invention.

As shown in FIG. 11A, correction patterns are formed on the pattern 40 such as "A" to "E". As described above, if a pattern in which correction patterns are designed is used as a second aperture according to an embodiment of the present invention, and a combination method of design data and a second aperture is used, it is exposed on a wafer as shown in FIG. 11B. In the pattern 40 'formed, the corners A', B ', C', D ', and E' may be prevented from being rounded due to the proximity effect.

Applying the present invention as described above can easily adjust the design data of the second aperture and the pattern of the second beam deformation portion, it is possible to solve the problem caused by the increase of data when it is necessary to expose the high integration pattern. In addition, since the second aperture can be formed and used in various sizes, the exposure process can be easily performed according to the design of the pattern or the size of the correction pattern required on the wafer.

Claims (12)

A beam source section for generating a controlled electron beam to form integrated circuit patterns on a target located in a target area, and a first cross section for modifying a cross-sectional shape of the electron beam generated and transmitted from the beam source section; In an exposure system including a first beam deformable part having an aperture formed thereon and a second beam deformed part formed an second aperture formed therein, a serif at a pattern designing stage of the semiconductor device to compensate for proximity effects In a method for correcting a proximity effect in an exposure system when performing an exposure process by adding a correction pattern such as) to an existing pattern, And forming a second aperture capable of embodying the shape of the correction pattern on the second beam deformable portion, and exposing a predetermined correction pattern added to the existing pattern. . The method of claim 1, And said target is a photomask. The method of claim 1, And said target is a wafer. The method of claim 3, wherein And a photomask for forming an image of a pattern exposed on said wafer is a photomask formed by said method. The method of claim 1, And said second aperture comprises at least one aperture of the same shape and of different dimensions. The method of claim 1, Forming an aperture in the second beam deformable portion that is the same as the first aperture in the first beam deformable portion. The method of claim 1, Selecting one of said second apertures and varying the dose upon exposure in said exposure system to expose it on said target. A beam source section for generating a controlled electron beam to form integrated circuit patterns on a target located in a target area, and a first cross section for modifying a cross-sectional shape of the electron beam generated and transmitted from the beam source section; In an exposure system including a first beam deformable part having an aperture formed thereon and a second beam deformed part formed an second aperture formed therein, a serif at a pattern designing stage of the semiconductor device to compensate for proximity effects In a method for correcting a proximity effect in an exposure system when performing an exposure process by adding a correction pattern such as) to an existing pattern, The second aperture forms at least one 2-1 aperture having a sub-aperture of a predetermined size to communicate with the main aperture at each vertex of the main aperture formed in a rectangular shape having a predetermined size, and the second aperture At least one surface extending inwardly from one side of the aperture formed in a square shape having a predetermined size to be equal to the shape of one side of the 2-1 aperture with respect to the vertical or horizontal centerline of the 2-1 aperture; Forming a shape of one second-2 aperture, and forming a shape of the other one side surface of the second first aperture that is not formed in the second second aperture in a form opposite to the second second aperture; At least one second to third aperture is formed in the same manner as the second to second aperture, and the correction pattern is formed in accordance with the second to second to second apertures, and is exposed. Exposing in correspondence with a second aperture of the same shape among the second apertures. The method of claim 8, And the sub aperture is rectangular in shape and a vertex in communication with the main aperture is located on the main aperture. The method of claim 8, And said second aperture comprises at least one aperture of the same shape and of different dimensions. The method of claim 8, Forming an aperture in the second beam deformable portion that is the same as the first aperture in the first beam deformable portion. The method of claim 8, Selecting one of said second apertures and varying the dose upon exposure in said exposure system to expose it on said target.