KR20090044580A - Lithography method and method for fabricaing semiconductor device using the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method and a method for manufacturing a semiconductor device using the same, and in particular, an exposure mask by applying a second incident illumination system (OAI) to an exposure mask optimized for a first off-axis illumination (OAI). By forming a pattern different from the layout of the substrate and forming various patterns with the exposure mask of the same layout, the technique can improve the margin of the exposure process.

Description

LITHOGRAPHY METHOD AND METHOD FOR FABRICAING SEMICONDUCTOR DEVICE USING THE SAME

The present invention relates to an exposure apparatus. In particular, the present invention relates to an exposure apparatus including off-axis illumination (OAI) and a method of manufacturing a semiconductor device using the same.

In general, a semiconductor device such as a DRAM (Dynamic Random Access Memory (DRAM)) is composed of a number of fine patterns, such fine patterns are formed through a photolithography process. In photolithography processes, resolution and depth of focus (DOF) are known to have two important issues. Among them, the resolution R may be expressed as in Equation 1 below. In Equation 1, k1 is a constant determined by photosensitive film type, thickness, and the like, λ is a wavelength of a light source to be used, and NA (Numerical aperture) is a numerical aperture of exposure equipment.

As can be seen from Equation 1, the shorter the wavelength λ of the light source to be used, and the larger the numerical aperture NA of the exposure apparatus, the smaller patterns can be implemented on the wafer. Currently, the degree of integration of the device is rapidly increasing, but the wavelength (λ) of the light source used and the numerical aperture (NA) of the exposure equipment cannot keep up with this. To this end, resolution enhancement technology (RET) has been applied to improve resolution and depth of focus using various methods. Such resolution enhancement techniques may include a phase shift mask (PSM), an incident illumination system (OAI), optical proximity correction (OPC), and the like.

However, in the case of applying the incident light illumination system (OAI), the incident light illumination system has been set so that the pitch of the pattern is not free. For example, the vertical line and space pattern was subjected to an exposure process by an exposure method to which an X-axis dipole incident illumination system was applied. However, as the design rule of the device is drastically reduced, it is difficult to form a pattern having sufficient margin even by an exposure method using an optimized incident light illumination system. In addition, in order to solve this problem, the exposure equipment having better performance is required, but the development capability of the exposure equipment has also reached its limit.

The present invention is an exposure method using an exposure apparatus including an incident illumination system (OAI), by applying a second incident illumination system to an exposure mask optimized for the first incident illumination system to form a pattern different from the layout of the exposure mask. . In addition, it is possible to form a pattern that is difficult to form as the design of the device is reduced by an exposure method for changing such exposure conditions. As a result, various patterns can be formed with one exposure mask, thereby improving the exposure margin. Therefore, the reliability and yield of an element can be improved.

Exposure method according to an embodiment of the present invention,

An exposure method using an exposure apparatus including an incident illumination system (OAI), the method comprising applying a second incident illumination system to an exposure mask optimized for a first incident illumination system.

Method for manufacturing a semiconductor device according to an embodiment of the present invention,

Forming a photoresist pattern by providing a semiconductor substrate including an etched layer, forming a photoresist film on the semiconductor substrate, and performing an exposure process and a development process to which the exposure method according to an embodiment of the present invention is applied to the photoresist film. And forming the etched layer pattern by etching the etched layer using the photoresist pattern as a mask.

In addition, the exposure method according to another embodiment of the present invention,

An exposure method using an exposure apparatus including an incident illumination system (OAI), the method includes applying an incident illumination system for forming an elliptical filler pattern on an elliptical contact hole mask.

Method of manufacturing a semiconductor device according to another embodiment of the present invention.

Forming a photosensitive film pattern by providing a semiconductor substrate including an etched layer, forming a photosensitive film on the semiconductor substrate, and performing an exposure process and a developing process applying the exposure method according to another embodiment of the present invention to the photosensitive film. And forming the etched layer pattern by etching the etched layer using the photoresist pattern as a mask.

And, the exposure method according to another embodiment of the present invention,

An exposure method using an exposure apparatus including an incident illumination system (OAI), the method includes applying an incident illumination system for forming an elliptical filler pattern on an elliptical contact hole mask.

Method of manufacturing a semiconductor device according to another embodiment of the present invention,

Providing a semiconductor substrate including an etched layer, forming a photoresist film on the semiconductor substrate, and performing an exposure process and a development process to which the exposure method according to another embodiment of the present invention is applied to the photoresist film. Forming an etching target layer pattern by etching the etching target layer using a photoresist pattern as a mask;

The present invention has the effect of forming various patterns having a sufficient margin with an exposure mask of the same layout. Therefore, there is an advantage that can improve the reliability and yield of the device. In addition, the use of the same exposure mask has the effect of reducing the manufacturing time and cost for the exposure mask. Therefore, there is an advantage that the exposure process margin can be improved.

The principle of the present invention is to design the device by changing the exposure conditions so that the application of the incident light illumination system (OAI) optimized for a certain exposure mask in lithography technology is applied to another incident illumination system free of the pitch of the pattern. As the rule shrinks, various patterns that are difficult to form may be implemented. Therefore, in spite of the development delay of exposure equipment corresponding to the reduction of the design rule of the device, the optimum pattern can be formed by changing the exposure conditions.

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

1 illustrates an optimized exposure mask for an oblique illumination system (OAI). Conventional OAI has an optimal exposure condition to a contact hole pattern and a two-dimensional pattern having a free pitch. Annular OAI has optimal exposure conditions for contact hole patterns or complex two-dimensional patterns that are not pitch free.

In addition, the cross pole OAI has an optimal exposure condition to a two-dimensional pattern in which the pitch is not freer than that of the annular incidence illumination system. Dipole OAI has an optimal exposure condition to one-dimensional patterns such as line and space, and is also advantageous for an oval type contact hole pattern or an island pattern.

2 is a diagram illustrating an exposure method according to an exemplary embodiment. An exposure process is performed by applying a Y-axis dipole incident illumination system as a mask defining an elliptical contact hole pattern. 2C is a simulation diagram of a pattern formed as the exposure energy increases. It can be seen that the long axis control of the elliptical contact hole with the free pitch is not easy (see FIG. 2C). Therefore, it can be seen that it is not easy to obtain a desired pattern in an exposure mask having a small design rule (see FIG. 2D).

3 is a view illustrating an exposure method according to another exemplary embodiment of the present invention. An exposure process is performed by applying an X-axis dipole incident illumination system as a mask defining an elliptical contact hole pattern. Meanwhile, FIG. 3 performs an exposure process by changing the incidence illumination system. That is, another pattern may be formed by performing an exposure process in which an incident light illumination system applied in FIG. 2 and another incident light illumination system are applied (see FIG. 3D). In particular, a line-and-space pattern may be formed by applying an X-axis dipole incident illumination system to a mask defining an elliptical contact hole pattern. On the other hand, it should be noted that the line-and-space pattern of the present invention is for the purpose of description and not of limitation.

4 is a view illustrating an exposure method according to another exemplary embodiment of the present invention. An exposure process using a cross pole OAI is performed as a mask defining an island type contact pattern in a horizontal direction. 4C is a simulation diagram of a pattern formed as the exposure energy increases. In addition, it can be seen that an island contact hole pattern in a horizontal direction in which margin is not sufficient is formed (see FIG. 4D).

5 is a view illustrating an exposure method according to another embodiment of the present invention. An exposure process using an X-axis dipole incident illumination system is performed as a mask defining an island type contact hole pattern in a horizontal direction. Meanwhile, FIG. 5 performs an exposure process in which the incident light illumination system is changed in the exposure process of FIG. 4. That is, another pattern may be formed by performing an exposure process to which the X-axis dipole incident light system and the X-axis dipole incident light system applied in FIG. 4 are applied. In particular, an X-axis dipole incident illumination system may be applied to a mask defining an island contact hole pattern in a horizontal direction to form an island pillar pattern in a vertical direction having sufficient margin (see FIG. 5D). Meanwhile, it should be noted that the island filler pattern of the present invention is for the purpose of description and not of limitation.

6A through 6C are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention. After the photoresist film 630 is formed on the semiconductor substrate 610 including the etched layer 620, the photoresist film 630 is exposed and developed by the exposure method illustrated in FIG. 3 to expose an exposure mask defined in an optimal incidence illumination system. Another incident light illumination system is applied to the line-and-space photoresist pattern 632. Next, after etching the etched layer 620 using the photoresist pattern 632 as an etching mask to form the etched layer pattern 622, the photoresist pattern 632 is removed.

In addition, in the method of manufacturing a semiconductor device according to another exemplary embodiment of the present disclosure, the island filler pattern in the vertical direction may be formed by exposing and developing the photoresist layer 630 using the exposure method illustrated in FIG. 5. On the other hand, it should be noted that the pattern formed by changing the incidence illumination system as described above is for the purpose of explanation and not for the purpose of limitation. In addition, the preferred embodiment of the present invention for the purpose of illustration, those skilled in the art will be able to various modifications, changes, substitutions and additions through the spirit and scope of the appended claims, such modifications and changes are the following claims It should be seen as belonging to a range.

1 illustrates an optimized exposure mask for an oblique illumination system (OAI).

2 is a view showing an exposure method according to an embodiment of the present invention.

3 is a view showing an exposure method according to another embodiment of the present invention.

4 is a view showing an exposure method according to another embodiment of the present invention.

5 is a view showing an exposure method according to another embodiment of the present invention.

6A through 6C are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

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

610: semiconductor substrate 620: etched layer

622: etching layer pattern 630: photosensitive film

632: photosensitive film pattern

Claims (6)

In the exposure method using an exposure apparatus including an off-axis illumination (OAI), And applying a second incidence illumination system to the exposure mask optimized for the first incidence illumination system. In the exposure method using the exposure apparatus containing an incident light illumination system (OAI), And applying an incident illumination system to form a line and space pattern in the elliptical contact hole mask. In the exposure method using the exposure apparatus containing an incident light illumination system (OAI), And applying an incident illumination system for forming an elliptical filler pattern in the elliptical contact hole mask. Providing a semiconductor substrate comprising an etched layer; Forming a photoresist film on the semiconductor substrate; Forming a photosensitive film pattern on the photosensitive film by performing an exposure process and a developing process to which the exposure method according to claim 1 is applied; And And etching the etched layer using the photoresist pattern as a mask to form an etched layer pattern. Providing a semiconductor substrate comprising an etched layer; Forming a photoresist film on the semiconductor substrate; Forming a photoresist pattern on the photoresist by performing an exposure process and a development process to which the exposure method according to claim 2 is applied; And And etching the etched layer using the photoresist pattern as a mask to form an etched layer pattern. Providing a semiconductor substrate comprising an etched layer; Forming a photoresist film on the semiconductor substrate; Forming a photoresist pattern on the photoresist by performing an exposure process and a development process to which the exposure method according to claim 3 is applied; And And etching the etched layer using the photoresist pattern as a mask to form an etched layer pattern.

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