JPH0322904Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field to which the idea belongs]

This invention uses a single reticle mask with different types of chip patterns to reduce and project any chip pattern on the reticle mask onto a photoresist layer formed on the surface of a semiconductor wafer and expose it to light. The present invention relates to a projection exposure apparatus.

[Prior art and its problems]

This type of reduction projection exposure equipment projects and transfers a reticle mask with a chip pattern 10 times or 5 times larger onto the wafer through a reduction lens using a step-and-repeat method. In this method, a plurality of chip patterns are formed and transferred onto a wafer as one shot. Generally, chip patterns formed on a semiconductor wafer include, in addition to a practical chip pattern 12 as shown in FIG. 13 are often formed on one wafer 11 at the same time. However, in order to form two or more different patterns on a wafer using a conventional reduction projection exposure system, it is necessary to separately prepare reticle masks for different chip patterns in addition to reticle masks for practical chip patterns. However, there have been disadvantages such as an increase in photomask manufacturing costs, a decrease in throughput due to reticle mask replacement during exposure, and a decrease in the embedding accuracy of different chip patterns.

[Purpose of invention]

As mentioned at the beginning, the present invention eliminates the above drawbacks and uses a single reticle mask in which different chip patterns coexist, and a chip pattern that allows different chip patterns to be formed on a semiconductor wafer as needed. An object of the present invention is to provide a reduction projection exposure apparatus.

[Key points of the idea]

The present invention is a chip pattern reduction exposure system that includes a projection light source, a support frame that supports a reticle mask with the pattern surface facing away from the light source, and an optical system that reduces and projects the chip pattern on the pattern surface onto a semiconductor wafer. By providing a light shielding plate that is close to the pattern surface of the reticle mask of the apparatus within 500 μm and is movable in parallel thereto, only an arbitrary chip pattern on the reticle mask can be projected, thereby achieving the above object.

[Example of idea]

FIG. 1 shows the state of use of an embodiment of the present invention,
The reticle mask 2 is attached to the reticle holder 4 by vacuum suction with the pattern surface 3 facing downward. 500μm from pattern surface 3 of reticle mask
A light shielding plate 5 is arranged at a lower part and can be moved to an arbitrary position in the direction of an arrow 6 according to instructions from an operating system. Thereby, only an arbitrary pattern portion of the reticle mask pattern surface can be projected and exposed to the photoresist layer on the surface of the semiconductor wafer 1 by the ultraviolet rays 7 through the reduction lens 8. 3 and 4 show a reticle mask 2 used in a chip pattern reduction projection exposure apparatus according to the present invention.
This is an example of the arrangement of a practical chip pattern 31 and a different type of chip pattern 32 for evaluation on the pattern surface 3. When projecting the different types of chip patterns 32, the mask is not covered with the light shielding plate 5 and is projected together with the practical chip pattern 31, and the different types of chip patterns 32 are covered with the light shielding plate 31 on other wafer surface areas to project only the practical chip patterns. . Therefore, it is desirable to arrange the different types of chip patterns 32 to be light-shielded around the chip patterns as shown in the figure in order to simplify the movement of the light-shielding plate. In the projection exposure apparatus according to the present invention, the reduction lens 8
For example, by reducing the reduction ratio to 1/5, the area of one chip pattern on the mask can be reduced to 1/4 compared to a reduction ratio of 1/10, without reducing the number of practical chip patterns on the mask. Therefore, even if different types of chip patterns coexist on the mask, the exposure operation time can be prevented from increasing. FIG. 5 shows the amount of light that wraps around the wafer when the distance from the pattern surface 3 of the reticle mask 2 to the back surface of the light shielding plate 5 is changed. Since the distance from the pattern surface 3 of the reticle mask 2 to the light shielding plate 5 is 500 μm as described above, the amount of light that wraps around the wafer is 100 μm, and no influence on adjacent patterns was observed.

[Effect of the idea]

According to the present invention, by arranging a movable light-shielding plate that can block part of the chip pattern directly below the pattern surface of the reticle mask within 500 μm, different types of chip patterns can be formed in addition to practical chip patterns. Different types of chip patterns can be projected onto a semiconductor wafer at arbitrary positions using a reticle mask, and by shielding different types of chip patterns when unnecessary, shots of only practical chip patterns can be projected with less light going around. As a result, it is possible to prevent a decrease in processing capacity due to reticle mask exchange and a decrease in embedding accuracy of different chip patterns, which were problems in the prior art, and it is possible to reduce photomask manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the use of an embodiment of the present invention, FIG. 2 is a plan view of an example of forming different types of chip patterns on a semiconductor wafer, and FIGS. 3 and 4 are projection exposure apparatuses according to the present invention. FIG. 5 is a diagram showing the relationship between the distance from the pattern surface of the reticle mask to the back surface of the light-shielding plate and the amount of wraparound on the wafer. 1: Semiconductor wafer, 2: Reticle mask, 3:
pattern surface, 4: reticle holder, 5: light shielding plate,
7: Ultraviolet rays, 8: Reduction lens, 31: Practical chip pattern, 32: Different types of chip patterns.

Claims (1)

[Scope of utility model registration request] A projection light source, a support frame that supports a reticle mask with a pattern surface on a side farther from the light source, and an optical system that reduces and projects a chip pattern on the pattern surface onto a wafer, the pattern surface of the reticle mask A chip pattern reduction projection exposure apparatus characterized by comprising a light shielding plate that is close to the pattern surface within 500 μm and is movable parallel to the pattern surface.