JPH08162390A - Light exposure device - Google Patents

Abstract

PURPOSE: To enhance a light exposure pattern in definition by a method wherein a wafer is supported by sporadically disposed pins, the flatness of the surface of the wafer is detected by a flatness measuring device, and the pins which support the wafer are controlled in height basing on flatness measurement data. CONSTITUTION: A wafer 3 is supported by the support 14 of a stage main body 8 by the peripheral part, but the inner part of the wafer 3 is supported by pins 10 arranged in array. The upper end faces of all the pins 10 are so set as to be flush with the upside of the support 14 of the stage main body 8. If a foreign object 15 is attached to the upper end face of the pin 10, the wafer 3 is lifted up higher by the thickness of the foreign object 15, and a height difference is measured by a flatness measuring device 5, and the pin 10 where the foreign object 15 is attached is made to descend by the measured height difference. If a part of the wafer 3 is low, the pin 10 which supports the low part of the wafer 3 is made to ascend by a proper length to be flush with the other pins.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, for example, a reduction projection exposure apparatus.

[0002]

2. Description of the Related Art An exposure apparatus is used in an exposure process in the manufacture of semiconductor devices such as IC and LSI. There are contact exposure type, reduction projection exposure type, proximity exposure type and the like in the exposure apparatus, and all of them are desired from above with a semiconductor substrate (wafer) having a photoresist film formed on its main surface placed on a stage. They are the same in that light is applied to the pattern to expose the photoresist film. The exposure apparatus is described, for example, in "Electronic Materials", March 1988 issue, published by the Industrial Research Society, March 30, 1988, P30 to P36.
This document describes an i-line reduction projection exposure apparatus. Further, this document illustrates the operation principle of an air micro type automatic focusing mechanism including an XY moving table, a Z moving table, a servo mechanism, a reduction lens and the like.

On the other hand, in a structure in which a wafer is placed on a flat stage, when foreign matter adheres to the stage, the wafer portion corresponding to the foreign matter rises, making it difficult to perform clear exposure. Therefore, a stage is used in which a plurality of thin pins are set up and the wafer is supported by the pins. As an exposure apparatus having a stage having a structure in which a plurality of thin pins are set up, there is, for example, "Nanoflat" manufactured by Hitachi Tokyo Electronics Co., Ltd., Catalog (No. 9302M1) and the like.

[0004]

As one of the exposure apparatuses used by the present applicant, there is one that supports a wafer on a stage in which a plurality of thin pins are set up as described above. In this structure, it was found that when foreign matter adheres to the pins, the wafer portion corresponding to the foreign matter rises and the exposure pattern becomes partially unclear.

An object of the present invention is to provide an exposure apparatus capable of exposing a clear pattern.

The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[0007]

The outline of the representative ones of the inventions disclosed in the present application will be briefly described as follows. That is, the exposure apparatus of the present invention is a semiconductor substrate (wafer) which is an object to be exposed by a plurality of pins
An exposure apparatus having a stage for supporting the pins, a pin height adjusting means for supporting the pins and moving the pins up and down, a flatness measuring device for detecting flatness of the surface of the semiconductor substrate, A controller for controlling the pin height adjusting means, and the controller is configured to control the height of each pin according to the information from the flatness measuring device. The pin is controlled up and down by a cam fixed to the rotation shaft of the stepping motor. In the exposure apparatus of the present invention, after the flatness of the wafer is measured before the exposure, when a partially raised or lowered portion is detected, the controller lowers or raises the pin of the corresponding portion. Then, correction is performed to flatten the wafer.

[0008]

According to the above means, in the exposure apparatus of the present invention, the wafer is supported by a large number of standing pins, and the flatness of the wafer is measured and corrected prior to exposure, A sharp pattern of exposure can be achieved. Therefore, even if the foreign matter is placed on the pins and the wafer partially rises, the wafer can be flattened by the correction, and the exposure yield is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing a main part of an exposure apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a pin height adjusting means.

The exposure apparatus of this embodiment is, for example, a reduction projection exposure apparatus, and as shown in FIG.
The stage 2 is arranged on the top. A semiconductor substrate (wafer) 3 is placed on the stage 2. Further, a lens barrel 4 having a reduction projection lens built therein is located above the stage 2. Further, a flatness measuring device 5 is arranged on the side of the lens barrel 4.

As shown in FIG. 2, the stage 2 has a box-shaped circular stage main body 8 having an open top, a guide plate 9 horizontally provided on the stage main body 8, and a perforated guide plate 9. It is formed by a pin 10 slidably inserted in a sloping guide hole, a cam (front cam) 11 that supports the lower end of the pin 10, and a stepping motor 12. The rotation shaft 13 of the stepping motor 12 extends in the vertical direction, and the cam 11 is provided on the upper end thereof.
Has been fixed.

Since the cam 11 is a front cam, the pin 10 moves up and down when the stepping motor 12 rotates forward and backward. In the present embodiment, the lower end of the pin 10 is always brought into contact with the cam surface of the cam 11 by its own weight, but the pin 10 may be always brought into contact with the cam 11 by a spring.

The peripheral portion of the wafer 3 is the stage body 8
Is supported by the support portion 14 of the above, but the portion inside the peripheral edge is supported by the plurality of pins 10 arranged in line. Further, in the set state, the upper end surfaces of all the pins 10 are set to be flush with the upper surface of the support portion 14 of the stage body 8. in this way,
The reason why the wafer 3 is supported by the pins 10 is to prevent the deformation (flatness) of the wafer 3 due to adhesion of foreign matter from being impaired. However, as shown in FIG. 2, when the foreign matter 15 adheres to the upper end surface of the pin 10, the wafer 3 becomes partially high. Therefore, in such a case, the increased length of the wafer 3 is While the flatness measuring device 5 measures, the pin 10 on which the foreign matter 15 is placed is lowered downward by the amount of the increase. When a part of the wafer 3 is low, the pins 10 supporting the low part are raised by the lowered length. This improves the flatness of the wafer 3.

The foreign matter 15 is supposed to be as small as about 1 μm in diameter, and the flatness should be corrected on the order of submicrons.

In the reduction projection exposure apparatus, the stage 2 steps the reduction projection lens to perform exposure. Therefore, the surface of the wafer 3 can be scanned.

The exposure apparatus of this embodiment is provided with a controller 20 as shown in FIG. The controller 20 controls the movement of the XY table 1 and also controls the pin height adjusting means, that is, each stepping motor 12 including the rotation amount. Further, flatness information obtained by scanning by the flatness measuring device 5 is sent to the controller 20. The XY table 1 may have a structure capable of moving in the vertical direction (Z direction).

In the exposure apparatus of this embodiment, the flatness of the wafer surface is measured prior to the exposure, the height of the pin 10 for supporting the wafer 3 is adjusted based on the flatness measurement information, and then the exposure is performed. Is done. Since the flatness of the surface of the wafer 3 is accurate to the submicron order of 1 μm or less, clear exposure is possible.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

[0019]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows. In the exposure apparatus of the present invention, the wafer is supported by a plurality of pins scattered and
The flatness of the surface of the wafer is detected by the flatness measuring instrument, and the height of the pins supporting each part of the wafer is adjusted based on the flatness measurement information. , It is possible to always expose a clear pattern. Therefore, the exposure yield is improved by using the exposure apparatus of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main part of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a part of pin height adjusting means in the exposure apparatus according to the present embodiment.

[Explanation of symbols]

1 ... XY table, 2 ... Stage, 3 ... Wafer, 4 ... Lens barrel, 5 ... Flatness measuring instrument, 8 ... Stage body, 9 ... Guide plate, 10 ... Pin, 11 ... Cam, 12 ... Stepping motor, 13 ... Rotating shaft, 14 ... Supporting part, 15 ... Foreign matter, 20 ...
controller.

Claims (3)

[Claims] 1. An exposure apparatus having a stage for supporting an object to be exposed by a plurality of pins, comprising pin height adjusting means for supporting the pins and moving the pins up and down.
It comprises a flatness measuring device for detecting the flatness of the surface of the semiconductor substrate, and a controller for controlling each pin height adjusting means, and the controller determines the height of each pin according to information from the flatness measuring device. An exposure apparatus that is configured to control. 2. The exposure apparatus according to claim 1, wherein the pin is controlled up and down by a cam fixed to a rotation shaft of a stepping motor. 3. The exposure apparatus according to claim 1, wherein the object to be exposed is a semiconductor substrate.