KR20100046468A - Method of forming mask pattern - Google Patents

Abstract

PURPOSE: A method for forming a mask pattern is provided to improve the slope of an inclined plane formed on an edge by performing exposure processes using a long wavelength light source and a short wavelength light source. CONSTITUTION: A photoresist is coated on an object. The photoresist is firstly exposed using a first mask(10) and a long wavelength light source. The photoresist is secondly exposed using a second mask and a short wavelength light source. The photoresist is developed after first and second exposure processes. A part exposed by the light is removed on the photoresist in the first and second exposure processes.

Description

Method of forming mask pattern

TECHNICAL FIELD The present invention relates to semiconductor technology, and more particularly, to a method of forming a mask pattern.

With the recent refinement of the mask design, the amount of light projected onto the mask by photolithography technology can be adjusted appropriately.

In addition, to overcome the technical limitations of the manufacturing apparatus, new photoresist development, a scanner equipped with a high-numerical aperture lens, and a deformation mask technology are being developed. In particular, Optical Proximity Correction (OPC) technology has helped us overcome the technical limitations of conventional optical exposure manufacturing equipment. As a result, the optical distortion phenomenon due to the optical proximity compensation can be effectively overcome, and as a result, the processing ability of the ultra fine pattern is increased.

In particular, recently, chemically amplified resists with excellent photosensitivity to ultraviolet light having a wavelength of 248 nm or 194 nm have been developed. This can be seen as the emergence of a practical technology that can further increase the resolution.

However, despite such technology development, factors affecting the resolution and uniformity of the mask pattern still remain, and the density of the mask pattern is important. If precise pattern control is not performed, there is a problem in that the margin of the exposure process is reduced.

1 is a view showing a mask pattern according to the prior art, Figures 2a and 2b are cross-sectional views showing a cross-section of a portion of the mask pattern of FIG.

As illustrated in FIG. 1, when the photoresist pattern 2 is formed on a semiconductor substrate, an inclined surface may be formed at an edge portion of the photoresist pattern 2.

The inclined surface may vary depending on the edge portion of the photoresist pattern 2, and the different shapes are shown in FIGS. 2A and 2B.

FIG. 2A shows a cross section in the longitudinal direction C-D of the pattern 2, and FIG. 2B shows a cross section in the line width direction A-B orthogonal to the longitudinal direction of the pattern 2. Comparing Figs. 2A and 2B, the difference in shape can be seen.

That is, the inclined surface 3 formed at the end of the pattern 2 in the cross section of the longitudinal direction C-D shown in FIG. 2A has a different inclination from the inclined surface 4 formed at the edge portion of the line width direction A-B.

On the other hand, when the inclination of the edge portion is large, there is a problem that it is difficult to accurately compensate for the inclined surface during optical proximity compensation (OPC).

Disclosure of Invention An object of the present invention is to provide a mask pattern forming method that satisfies the above-described problems of the prior art, and satisfies an optimal compensation condition to facilitate optical proximity compensation (OPC).

It is another object of the present invention to provide a mask pattern forming method that facilitates optical proximity compensation (OPC) by improving the slope of the inclined surface formed at the edge portion of the mask pattern.

According to an aspect of the present invention, there is provided a method of forming a mask pattern according to an embodiment of the present invention, comprising: applying a photoresist to an object, and exposing the photoresist to a plurality of different light sources using the same mask Developing and removing a portion of the photoresist exposed to light during the exposure.

Preferably, the step of developing after exposing a plurality of times, the first exposure to a light source of a long wavelength using the mask, and the second exposure to a light source of a short wavelength using the mask may be a step of developing. have. Here, the long wavelength light source may be a KrF wavelength light source, and the short wavelength light source may be an ArF wavelength light source.

Another aspect of the method for forming a mask pattern according to the present invention for achieving the above object is the step of applying a photoresist on an object, the first exposure to the photoresist using a mask and a long wavelength light source and And developing the photoresist after the second exposure using the mask and the short wavelength light source, and removing a portion of the photoresist exposed to light during the first to second exposures.

Another feature of the method for forming a mask pattern according to the present invention for achieving the above object is the step of applying a photoresist on an object, the first exposure to the photoresist using a first mask and a long wavelength light source Performing a second exposure to the photoresist using the first mask and a short wavelength light source, and performing a third exposure to the photoresist using a second mask and the long wavelength light source; And developing the photoresist after the fourth exposure using the second mask and the light source of the short wavelength, and removing a portion of the photoresist exposed to light during the first to fourth exposures. will be.

Another feature of the method for forming a mask pattern according to the present invention for achieving the above object is the step of applying a long wavelength photoresist on an object, using a first mask and a long wavelength light source for the photoresist 1 Differential exposure, second exposure of the photoresist using a second mask and the long wavelength light source, and third exposure of the photoresist using the second mask and the short wavelength light source Developing and removing portions of the photoresist exposed to light during the first to third exposures.

Another feature of the mask pattern forming method according to the present invention for achieving the above object is the step of applying a long-wavelength photoresist on the object, using a first mask and a long wavelength light source for the photoresist 1 And exposing the photoresist to the photoresist, using a second mask and a short wavelength light source, and then developing the photoresist; and removing portions of the photoresist exposed to light during the first to second exposures. It is made up of steps.

According to the present invention, the inclination of the inclined surface formed at the mask pattern edge portion can be uniformly controlled, thereby facilitating optical proximity compensation (OPC).

In addition, in the present invention, the inclination of the inclined surface formed at the edge portion can be improved by further performing a plurality of exposure processes, that is, exposure using a long wavelength light source, followed by exposure using a short wavelength light source before the developing step. Therefore, an easy shape for optical proximity compensation (OPC) can be obtained at the edge portion of the finished mask pattern.

In addition, since the mask pattern formed in the present invention is easy for optical proximity compensation (OPC), it is possible to adjust the line width of the pattern more accurately.

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described by at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

In the present invention, a mask pattern is formed using one or more masks.

First, a method of forming a mask pattern using one mask will be described first in a first embodiment, and a method of forming a mask pattern using a plurality of masks will be described in a second embodiment. However, the method of forming the mask pattern using one mask as in the first embodiment can be sufficiently understood from the second embodiment using a plurality of masks as shown in FIGS. Omit.

First Embodiment

First, a photoresist is applied onto the object. The object may be a material film to be etched using a mask pattern that is finally completed or a wafer to be ion implanted using the mask pattern. The photoresist is an organic resist, and in the present invention, it is particularly preferable that the photoresist is a long wavelength organic resist.

Subsequently, the applied photoresist is exposed to different light sources multiple times using one and the same mask. In detail, first, a photoresist is first exposed to a long wavelength light source using a mask, and then a second photoresist is exposed to a short wavelength light source using the same mask. After the first and second consecutive exposures described above, a development process is performed, thereby removing a portion of the photoresist exposed to light during the exposure.

In the above, it is preferable that the long wavelength light source uses a KrF wavelength light source, and the short wavelength light source uses an ArF wavelength light source. Here, the long wavelength resist is used as the photoresist, and the long wavelength resist absorbs almost all of the short wavelengths used for the secondary exposure due to its high light absorption rate.

On the other hand, after removing the portion exposed to light during exposure in the above, it is preferable to proceed with a deionized water rinse (Di Rinse) process for cleaning, after drying the mask pattern is completed on the object.

Second Embodiment

First, a photoresist is applied onto the object. In this case, the object may be a material film to be etched using a mask pattern finally completed as described above, or a wafer to be ion implanted using the mask pattern. The photoresist is an organic resist, and in the present invention, it is particularly preferable that the photoresist is a long wavelength organic resist.

Subsequently, the coated photoresist is exposed at least once to different light sources using the masks shown in FIGS. 3 and 4. In the second embodiment described below, one exposure process is performed using the first mask, and a development process is performed after one exposure using the second mask.

3 is a view showing a first mask shape according to the present invention, FIG. 4 is a view showing a second mask shape according to the present invention. In the second embodiment, an exposure process is performed using at least two masks. .

In the first mask 10 of FIG. 3, light blocking regions 11 and 12 and a light transmitting region 13 are disposed on a transparent mask disc. One of the light blocking regions 11 and 12 may be an area for forming a part of the mask pattern. In the second mask 20 of FIG. 4, the light shielding area 21 and the light transmitting areas 22 and 23 are disposed on the transparent mask disc. The light transmission regions 22 and 23 may be regions for removing a portion of the mask pattern formed by using the first mask 10.

First, the first exposure is performed on the pre-coated photoresist using the first mask 10 of FIG. 3 and using a long wavelength light source. By the first exposure, a photoreaction occurs inside the photoresist corresponding to the light transmission region 13, thereby forming a latent image. The long wavelength light source uses a KrF wavelength light source.

Subsequently, the second exposure is performed on the first exposed photoresist using the second mask 20 of FIG. 4 and using a light source having a short wavelength. The secondary exposure causes a photoreaction inside the photoresist corresponding to the light transmission regions 22 and 23, thereby forming a latent image. The short wavelength light source uses an ArF wavelength light source.

After the first and second exposures described above, a development process is performed, thereby removing portions of the photoresist exposed to light during the exposure.

On the other hand, after removing the portion exposed to light during exposure in the above, it is preferable to proceed with a deionized water (Di Rinse) process for cleaning, after drying the mask pattern shown in Figure 7 is completed on the object.

Third Embodiment

First, a photoresist is applied onto the object. In this case, the object may be a material film to be etched using a mask pattern finally completed as described above, or a wafer to be ion implanted using the mask pattern. The photoresist is an organic resist, and in the present invention, it is particularly preferable that the photoresist is a long wavelength organic resist.

Subsequently, the coated photoresist is exposed at least once to different light sources using the masks shown in FIGS. 3 and 4. In the following third embodiment, one exposure process is performed using the first mask, and the development process is performed after two exposures using the second mask.

3 is a view showing a first mask shape according to the present invention, FIG. 4 is a view showing a second mask shape according to the present invention. In the third embodiment, an exposure process is performed using at least two masks.

First, the first exposure is performed on the pre-coated photoresist using the first mask 10 of FIG. 3 and using a long wavelength light source. By the first exposure, a photoreaction occurs inside the photoresist corresponding to the light transmission region 13, thereby forming a latent image. The long wavelength light source uses a KrF wavelength light source.

Subsequently, secondary exposure is performed on the first exposed photoresist using the second mask 20 of FIG. 4 and using a long wavelength light source. The photoreaction occurs inside the photoresist corresponding to the light transmission region 13 by the secondary exposure. The long wavelength light source uses a KrF wavelength light source.

Subsequently, the third exposure is performed on the first to second exposed photoresists by further using the second mask 20 of FIG. 4 and using a short wavelength light source. By the third exposure, a photoreaction occurs inside the photoresist corresponding to the light transmission areas 22 and 23, thereby forming a latent image. The short wavelength light source uses an ArF wavelength light source.

After the first to third exposures described above, a development process is performed, thereby removing a portion of the photoresist exposed to light during the exposure.

On the other hand, after removing the portion exposed to light during exposure in the above, it is preferable to proceed with a deionized water (Di Rinse) process for cleaning, after drying the mask pattern shown in Figure 7 is completed on the object.

Fourth Embodiment

First, a photoresist is applied onto the object. In this case, the object may be a material film to be etched using a mask pattern finally completed as described above, or a wafer to be ion implanted using the mask pattern. The photoresist is an organic resist, and in the present invention, it is particularly preferable that the photoresist is a long wavelength organic resist.

Subsequently, the coated photoresist is exposed to a plurality of times with different light sources using the masks shown in FIGS. 3 and 4. In the following fourth embodiment, two exposure processes are performed using the first mask, and a developing process is performed after two exposures using the second mask.

3 is a view showing a first mask shape according to the present invention, FIG. 4 is a view showing a second mask shape according to the present invention. In the fourth embodiment, an exposure process is performed using at least two masks. 5 and 6 are views for explaining a process of second exposure to different light sources while using the same mask according to the present invention.

First, the first exposure is performed on the pre-coated photoresist as shown in FIG. 5 using the first mask 10 of FIG. 3 and using a long wavelength light source. By the first exposure, a photoreaction occurs inside the photoresist corresponding to the light transmission region 13, thereby forming a latent image. The long wavelength light source uses a KrF wavelength light source.

Subsequently, secondary exposure is performed on the first exposed photoresist as shown in FIG. 6 by further using the first mask 10 of FIG. 3 and using a short wavelength light source. The photoreaction occurs inside the photoresist corresponding to the light transmission region 13 by the secondary exposure. The short wavelength light source uses an ArF wavelength light source.

Subsequently, the third exposure is performed on the first to second exposed photoresists using the second mask 20 of FIG. 4 and using a long wavelength light source. The light reaction occurs inside the photoresist corresponding to the light transmission regions 22 and 23 by the third exposure, thereby forming a latent image. The long wavelength light source uses a KrF wavelength light source.

Subsequently, the fourth exposure is performed on the first to third exposure photoresists while further using the second mask 20 of FIG. 4 and using a short wavelength light source. The light reaction occurs inside the photoresist corresponding to the light transmission regions 22 and 23 by the fourth exposure. The short wavelength light source uses an ArF wavelength light source.

After the first to fourth exposures described above, a development process is performed, thereby removing a portion of the photoresist exposed to light during the exposure.

On the other hand, after removing the portion exposed to light during exposure in the above, it is preferable to proceed with a deionized water (Di Rinse) process for cleaning, after drying the mask pattern shown in Figure 7 is completed on the object.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

1 is a view showing a mask pattern according to the prior art

2A and 2B are cross-sectional views illustrating a cross section of a portion of the mask pattern of FIG. 1.

3 is a view showing a first mask shape according to the present invention.

4 is a view showing a second mask shape according to the present invention.

5 and 6 are views for explaining a process of second exposure to different light sources while using the same mask according to the present invention.

7 is a view showing the shape of the completed mask pattern after exposure and development according to the present invention.

Claims (11)

Applying a photoresist on the object; Exposing the photoresist to different light sources a plurality of times using the same mask and then developing the photoresist; And removing a portion of the photoresist exposed to light during the exposure. The method of claim 1, wherein the developing after the plurality of exposures comprises: Firstly exposing to a long wavelength light source using the mask; And a step of developing after the second exposure to a light source having a short wavelength using the mask. The method of claim 2, wherein the long wavelength light source is a KrF wavelength light source, and the short wavelength light source is an ArF wavelength light source. Applying a photoresist on the object; Firstly exposing the photoresist using a mask and a long wavelength light source; Developing the photoresist after the second exposure using the mask and a short wavelength light source; And removing a portion of the photoresist exposed to light during the first to second exposures in the photoresist. Applying a photoresist on the object; Firstly exposing the photoresist using a first mask and a long wavelength light source; Second exposure to the photoresist using the first mask and a short wavelength light source; Performing a third exposure to the photoresist using a second mask and the long wavelength light source; Developing the photoresist after the fourth exposure using the second mask and the short wavelength light source; Removing a portion of the photoresist exposed to light during the first to fourth exposures in the photoresist. The method of claim 4, wherein the photoresist is a long wavelength photoresist. The mask pattern forming method according to claim 4 or 5, wherein a light source having a KrF wavelength is used as the long wavelength light source. The mask pattern forming method according to claim 4 or 5, wherein an ArF wavelength light source is used as the short wavelength light source. Applying a long wavelength photoresist on an object; Firstly exposing the photoresist using a first mask and a long wavelength light source; Second exposure to the photoresist using a second mask and the long wavelength light source; Developing the photoresist after the third exposure using the second mask and a short wavelength light source; And removing a portion of the photoresist exposed to light during the first to third exposures in the photoresist. Applying a long wavelength photoresist on an object; Firstly exposing the photoresist using a first mask and a long wavelength light source; Developing the photoresist after the second exposure using the second mask and a short wavelength light source; And removing a portion of the photoresist exposed to light during the first to second exposures in the photoresist. The mask pattern forming method according to claim 9 or 10, wherein a light source having a KrF wavelength is used as the long wavelength light source, and a light source having an ArF wavelength is used as the short wavelength light source.

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