KR20030089761A - Exposure system of semiconductor device - Google Patents

Abstract

PURPOSE: An exposure system of a semiconductor device is provided to reduce exposing time and to improve yield by easily forming fields according to net die shapes of a wafer edge. CONSTITUTION: An exposure system is provided with a double mask blade(61). The double mask blade(61) is formed on a reticle(62) for selectively exposing field. At this time, the double mask blade(61) further includes a main mask blade(61A) and a sub mask blade(61B). The sub mask blade(61B) is restructured according to the field. Also, the sub mask blade(61B) synchronizes with the scanning movement of the reticle(62).

Description

Exposure system of semiconductor device {EXPOSURE SYSTEM OF SEMICONDUCTOR DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to exposure systems for semiconductor devices, and more particularly to exposure systems for semiconductor devices employing double mask blades.

As the semiconductor memory device is highly integrated, the shape of the storage node electrode, which is a lower electrode of the capacitor, is formed in an inner cylindrical shape.

1A to 1E and 2A to 2E are diagrams for explaining a method of forming the internal cylindrical strobe node electrode, and FIGS. 1A to 1E show a center portion of a wafer, and FIGS. 2A to 2E show a wafer. Edge parts are shown, respectively.

As illustrated in FIGS. 1A and 2A, an oxide film 11 for forming a capacitor is deposited on a semiconductor substrate 10 on which a predetermined process is completed, and a photoresist pattern (not shown) is formed on the oxide film 11 by a photolithography process. C). Then, the oxide film 11 is etched using this photoresist pattern as a mask to form the oxide film pattern 11A as shown in Figs. 1B and 2B, and then the photoresist pattern is removed by a known method.

1C and 2C, the polysilicon film 12 is deposited as an electrode material on the oxide film pattern 11A and the surface of the substrate 10, and the surface of the oxide film pattern 11A is exposed. The polysilicon film 12 is etched using chemical mechanical polishing (CMP) to form storage node electrodes 12A insulated from each other, as shown in FIGS. 1D and 2D. Thereafter, as shown in Figs. 1E and 2E, the oxide film pattern 11A is removed.

In this case, the photolithography process for forming the photoresist pattern is generally subjected to the steps of coating, aligning and exposing the photoresist film, developing and inspecting, among which a stepper is used as an apparatus for performing alignment and exposure. do. However, in such a stepper, if the focus is not set, a pattern may be widened or thinned, and a defect may occur in which a CD (Cridical Dimension) is not formed to a normal width. In particular, this phenomenon inevitably occurs at the edge portion of the wafer, and as shown in FIGS. 2B to 2E, an open fail occurs when the oxide pattern 11A is formed, which is then referred to as a storage electrode ( Inducing the lifting of 12A) causes the defect 100.

In order to solve this problem, a method of omitting the exposure of the wafer edge field has been proposed. However, in this case, since the yield is remarkably reduced due to the reduction of the number of net dies, it is rarely used. Also, in addition to a field capable of exposing six chips on six reticles that are commonly used (see FIG. 3A), a field capable of exposing only one or two chips on one or two reticles (see FIG. 3B). ) Is manufactured separately and used in the wafer edge portion, but the wafer exposure time is long in this case.

In addition, as shown in Figure 4, since the shape of the edge net die of the wafer forms a polygonal shape of various forms, it is difficult to implement this, but also has a long time problem. That is, since the mask blade of a scanner of a general exposure apparatus has the same size as the field size only in the slit direction and the Y direction, that is, the field size is adjusted by the scanning length in the Y direction, that is, in the scanning direction, This is because it is difficult to expose the various polygons in real time.

The present invention has been proposed to solve the problems of the prior art as described above, and the semiconductor device exposure can be improved by easily realizing the field according to the various net die shape of the wafer edge while reducing the exposure time The purpose is to provide a system.

1A to 1E and 2A to 2E are views for explaining a method of forming a conventional inner cylindrical straw electrode electrode;

1A to 1E are views showing a central portion of a wafer;

2A-2E illustrate an edge portion of a wafer.

3A and 3B illustrate field shapes.

4 shows the shape of an edge portion of a wafer;

5 schematically illustrates an exposure system of a semiconductor device according to an embodiment of the present invention.

6 is a view for explaining the principle of selective exposure when applying a double mask blade according to an embodiment of the present invention.

※ Explanation of symbols for main parts of drawing

50: exposure source 60: illumination system

61: Mask Blade 61A: Main Mask Blade

61B: Submask Blade

62: reticle 70: projection lens system

80 wafer

According to an aspect of the present invention for achieving the above technical problem, the object of the present invention includes a double mask blade disposed on the reticle to selectively expose the field, the double mask blade is a main mask blade and sub It is made of a mask blade, it can be achieved by an exposure system of a semiconductor device, characterized in that the sub mask blade is reconfigured according to the field.

Preferably, the sub mask blade is synchronized with the scanning movement of the reticle. In addition, the sub mask blade is configured by selectively applying a frame shaped according to the field, or a combination of elements varying in the X and Y axis directions depending on the field.

Hereinafter, preferred embodiments of the present invention will be introduced in order to enable those skilled in the art to more easily carry out the present invention.

5 is a diagram schematically illustrating an exposure system of a semiconductor device according to an exemplary embodiment of the present invention, and FIG. 6 is a diagram for describing a selective exposure principle when a double mask blade is applied.

As shown in FIG. 5, the exposure system is composed of an exposure source 50, an illumination system 60, a projection lens system 70, and a wafer 80. The illumination system 60 is comprised of the mask blade 61 and the reticle 62 arrange | positioned under this mask blade 61, The mask blade 61 carries out the light from the exposure source 50, and the projection lens system The area transferred to the wafer 80 through 70 is adjusted.

Here, the mask blade 61 is composed of a main mask blade 61A and a double mask blade of a sub mask blade 61B disposed below the main mask blade 61A, and the main mask blade 61A. In the same way as in the prior art, the slit direction has the same field size as the X direction, and since the sub mask blade 61B operates in synchronization with the scanning movement of the reticle (arrow direction and Y direction in FIG. 5), the sub mask blade 61B ) Can be operated in a stable state compared to the main mask blade 61A serving as a complex shutter.

In addition, the sub mask blade 61B is reconstructed according to an exposure map in each wafer edge field to enable selective exposure. That is, the selective exposure by the sub mask blade 61B may be performed by selectively configuring the sub mask blade 61B by applying a standardized frame, or by combining elements that vary in the X and Y axis directions. Can be.

FIG. 6 is a view for explaining the principle of exposure when the above-mentioned double mask blade 61 is applied. As shown in FIG. 6, the shape of the sub mask blade 61B is configured differently according to the shape of the exposure area, so that the wafer It can be seen that by implementing various polygonal shapes of the edge portion, selective exposure of the wafer edge field is possible.

According to the above embodiment, the mask blade is composed of the double mask blades of the main and sub mask blades, and thus the selective exposure is possible by reconstructing the sub mask blades according to the exposure map of the wafer edge, thereby increasing the number of net dies of the wafer edge portion. This can improve the yield in manufacturing a semiconductor device. In addition, since the positional accuracy of the mask blade is improved, defects caused by defocus or ghost images may be prevented.

Meanwhile, in the above embodiment, the sub mask blade is disposed under the main mask blade. Alternatively, the sub mask blade may be disposed above the main mask blade.

In the above embodiment, only the case where the selective exposure by the double mask blade is applied to the wafer edge field has been described. However, in addition to this case, the present invention can also be applied to the case where an alignment mark or a test pattern is formed in the wafer.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The above-described present invention can not only improve the yield in manufacturing a semiconductor device by selective exposure by the double mask blade, but also improve the positional accuracy of the mask blade to prevent defects caused by defocus and the like.

Claims (4)

A double mask blade disposed over the reticle to selectively expose the field, The double mask blades may include a main mask blade and a sub mask blade, and reconfigure the sub mask blades according to the field. The method of claim 1, And the sub mask blades are synchronized with the scanning motion of the reticle. The method of claim 1, The sub mask blades are configured by selectively applying a frame shaped according to the field. The method of claim 1, And the sub mask blades are configured by combining elements varying in the X and Y-axis directions according to the field.