JPH08203797A - Exposure equipment - Google Patents

Abstract

(57) [Abstract] [Object] The present invention realizes highly accurate exposure for an exposure apparatus. [Structure] A mask (3) and a photosensitive substrate (4) are arranged so as to face each other such that the in-plane direction of the mask (3) and the photosensitive substrate (4) are in the direction of gravity, and the lower side of the mask (3) is After the mask (3) is moved within the holding surface of the mask stage means (5) by the supporting position adjusting means (15A, 15B) to align the mask (3) and the mask stage means (5). , The mask (3) and the photosensitive substrate (4) are aligned. Position detection means (21-2
The position of the mask (3) with respect to the photosensitive substrate (4) is detected by means of 3) and kept in a predetermined positional relationship. As a result, before the mask (3) and the photosensitive substrate (4) are aligned with each other, the rotation amount of the mask stage means (5) is adjusted to the position detection means (21 to 21).
It can be suppressed to the measurement allowable value of 23) or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, and is preferably applied to an exposure apparatus used for manufacturing a liquid crystal display device, for example.

[0002]

2. Description of the Related Art Conventionally, in an exposure apparatus of this type, a mask is generally placed on a mask stage horizontally by a mask loader or the like in the direction of gravity, and alignment marks marked on the mask are By measuring the position with an alignment microscope and moving the position of the mask stage, the mask is aligned with the reference position of the exposure apparatus for exposure. After aligning the alignment mark with the reference position of the exposure apparatus, the mask stage is fixed so as to hold the alignment position during the exposure.

[0003]

However, when the mask is placed horizontally on the mask stage with respect to the direction of gravity as described above, in the case of a large mask, there is a problem that the mask bends due to gravity. Further, in the case of a scanning type exposure apparatus that holds a mask and a photosensitive substrate integrally on a carriage (scanning stage) and scans the carriage with respect to the projection optical system to perform exposure, the position of the mask stage is set to an alignment position during exposure. Even if it is fixed, when the scanning stage is tilted, the position of the mask stage shifts from a predetermined position, and a distorted pattern image is transferred to the photosensitive substrate. In order to solve this problem, it is possible to detect the mask stage position with an interferometer system and control the mask stage position with high accuracy during exposure to correct the mask distortion and mask stage displacement. To be

However, when the rotation of the mask stage exceeds a certain value (for example, 1 '), there is a problem that the interferometer cannot detect the mask stage position. The position accuracy of the mask pattern is
It is about 0.5 mm, and when the mask is placed on the mask stage based on the external shape and the mask is aligned according to the mask alignment mark, the rotation of the mask stage may exceed the certain value. It was necessary to mount the position of the mask in the rotational direction with respect to the stage at an accurate position below the certain value. In this case, there is a method of using a corner cube for the moving mirror of the mask stage to operate the interferometer normally even when the mask stage is largely rotated, but the corner cube has a large size, so a projection optical system with a small working distance is used. It cannot be used in the exposure apparatus used.

The present invention has been made in consideration of the above points, and provides an exposure apparatus capable of accurately prealigning the position of the mask in the rotational direction with a simple structure and not adversely affecting the position detection by the interferometer. It is a proposal.

[0006]

In order to solve such a problem, in the present invention, a mask (3) and a photosensitive substrate (4), which are arranged so as to face each other so that the in-plane direction is the direction of gravity, are projected optical. In the exposure device (1) that exposes the entire surface of the mask (3) onto the photosensitive substrate (4) by scanning the system (2), the mask (3) is held and moved on a predetermined holding surface. Mask stage means (5) and mask (3)
The mask tilt preventing means (12) for supporting the mask on the holding surface of the mask stage means (5) and the lower side surface of the mask (3), and also for supporting the mask (3) on the mask stage means (5).
Position adjusting means (15A, 15B) for aligning the mask (3) with the mask stage means (5) by moving the mask stage means (5) with respect to the photosensitive substrate (4). The position detecting means (19A, 19B, 19C, 21 to 23) for detecting is detected.

Further, in the present invention, the mask stage means (5) and the mask tilt prevention means (12) are respectively provided with ventilation holes ((16, 1) on the surface facing the mask (3).
7), 18), and when the mask (3) and the mask stage means (5) are aligned with each other, each vent hole ((16, 1)
By supplying compressed air through 7), 18),
A gas layer is formed between the mask (3) and the mask tilt prevention means (12) and the mask (3) and the mask stage means (5) to align the mask (3) and the mask stage means (5). After finishing, the mask stage means (5)
The mask (3) was attracted to the holding surface of the mask stage means (5) by drawing a vacuum through the ventilation holes (16, 17) of the mask stage means (5).

[0008]

The mask (3) and the photosensitive substrate (4) are arranged so as to face each other so that the in-plane direction of the mask (3) and the photosensitive substrate (4) are the gravity direction. Position adjusting means (15A, 15) for preventing the distortion of 3) and supporting the lower side of the mask arranged in the gravity direction.
B), the mask (3) is moved to the mask stage means (5).
After the mask (3) and the mask stage means (5) are aligned (pre-aligned) within the holding surface of the substrate, the position of the mask stage means (5) with respect to the photosensitive substrate (4) is detected by the position detecting means. (19A, 19B, 19C, 2
1 to 23) so that the mask (3) and the photosensitive substrate (4) are aligned with each other, so that the mask (3) and the photosensitive substrate (4) can be easily aligned before they are aligned with each other. With such a configuration, the mask can be pre-aligned so that the rotation amount of the mask stage means (5) is equal to or less than the allowable value of the position detecting means (19A, 19B, 19C, 21 to 23). The position detecting means (19A, 19B, 19C, 21 to 23) increases as the rotation amount of the mask stage increases when aligning the photosensitive substrate (4).
It is possible to prevent the position detection by
Therefore, highly accurate exposure can be realized.

When the mask (3) and the mask stage means (5) are aligned, the space between the mask (3) and the mask stage means (5) and between the mask (3) and the biasing means (12, 13, 14). ) To form a gas layer to reduce the resistance of the mask (3) when it moves, so that the mask (3) and the mask stage means (5) can be easily aligned with each other. You can

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 generally shows a schematic structure of an exposure apparatus according to an embodiment of the present invention. The exposure apparatus 1 is formed on the mask 3 by scanning the mask 3 and the photosensitive substrate 4 which are arranged so as to face each other with the projection optical system 2 in between and scanning the projection optical system 2 in synchronization with the Y direction. The (or drawn) original image pattern is projected and exposed on the photosensitive substrate 4.

Next, the configuration of each part will be described. As shown in FIG. 1, the mask 3 and the photosensitive substrate 4 are attached to a U-shaped scanning stage 7 via a mask stage 5 and a plate stage 6, respectively. The scanning stage 7 is attached to a main body (not shown) so as to be movable in the Y direction along a guide 8. By driving the scanning stage 7 at a constant speed, the mask 3 and the photosensitive substrate 4 are synchronized. The scanning is adapted to be realized. An illumination optical system (not shown) is held in the main body, and the mask 3 is illuminated by the illumination light (FIG. 2) emitted from the illumination optical system.
The original image pattern formed (or drawn) on the photosensitive substrate 4 is projected through the projection optical system 2.

Further, the exposure apparatus 1 includes a mask 3 and a photosensitive substrate 4.
Two alignment microscopes 9 and 10 (FIG. 2) are prepared for accurately aligning and, and are used for measuring the relative position between the mask 3 and the photosensitive substrate 4. That is, the alignment microscopes 9 and 10 are fixed to the main body together with the projection optical system 2, and the relative position measurement marks (not shown) arranged at arbitrary positions in the scanning direction (Y direction) of the mask 3 and the photosensitive substrate 4. However, the fine alignment mark will be referred to hereinafter). Further, two pre-alignment marks 11 are marked on the mask 3, and the positions of these pre-alignment marks 11 are measured by the alignment microscopes 9 and 10 to align the mask 3 and the mask stage 5 (hereinafter This is called pre-alignment).

The mask stage 5 is designed to move while holding the mask 3 on a predetermined holding surface. As shown in FIG. 2, the mask 3 is arranged so that the in-plane direction of the mask 3 is the direction of gravity. And is held on the holding surface of the mask stage 5 by the three biasing pads 12. That is, the biasing pad 12 is rotated by a biasing pad driving unit 13 attached to the mask stage 5, and the mask 3 is placed on the holding surface of the mask stage 5 by, for example, a mask loading mechanism. At the same time, the urging pad drive unit 13 sets the urging pad 12 to the urging position (the position shown in FIG. 1).
The mask 3 is held on the holding surface of the mask stage 5 by the urging force of the mask 4, thereby preventing the mask 3 from tilting. Therefore, even if the mask loading exits, the mask will not fall down. Further, the urging pad 12 is placed at a position retracted by the urging pad driving unit 13 when the mask 3 is not placed on the mask stage 5, so that the loading of the mask 3 is not hindered.

As shown in FIGS. 1 and 2, the mask 3 is
The lower side surface of the mask 3 is supported in the direction of gravity by two pre-alignment shafts 15A and 15B driven by a pre-alignment shaft driving unit 15 attached to the mask stage 5. Pre-alignment axis 1
5A and 15B are driven in the Z direction by the pre-alignment axis drive unit 15, whereby the mask 3 can be moved within the holding surface of the mask stage 5. Further, the mask 3 can be rotated around the optical axis of the illumination light by alternately moving the two pre-alignment axes 15A and 15B up and down (reversing the driving direction).

Also, pre-alignment shafts 15A and 15B
For ensuring the bias of the mask 3 (so that the mask 3 moves smoothly when biasing the mask 3), the mask surface 3
It is movable in the vertical direction (X direction) with respect to A. On the other hand, the mask stage 5 can move in parallel (Z direction) with respect to the mask surface 3A and can rotate around an axis perpendicular to the mask 3. Here, mainly mask 3
Is rotated by the pre-alignment axes 15A and 15B, and parallel movement is performed by the mask stage 5.

Here, as shown in FIG. 2, in order to smooth the movement of the mask 3 when the mask 3 and the mask stage 5 are pre-aligned, a ventilation hole for adsorbing the mask is provided in each of the upper part and the lower part of the mask stage 5. 16 and 17 are provided, and the biasing pad 12 is also provided with a vent hole 18. That is, the nozzles 16A, 17A, 18A
From the mask 3 and the mask stage 5 by supplying compressed air from these through the ventilation holes 16, 17, and 18.
A gas layer is formed between the chuck surface and the mask 3 and the biasing pad 12 to reduce the resistance when the mask moves. Thereby, the mask 3 and the mask stage 5 can be easily pre-aligned.

Like the mask 3, the photosensitive substrate 4 is fixed to the plate stage 6 such that the in-plane direction of the photosensitive substrate 4 is the direction of gravity. Therefore, the exposure surface 4A of the photosensitive substrate 4 and the mask surface 3A are arranged in parallel. The plate stage 6 can move in the vertical direction (X direction) with respect to the exposure surface 4A and can tilt and move, so that the exposure surface 4A is aligned (focused) with the image forming position (image forming surface) of the mask pattern. It can be done.

Mirrors 19A and 19B are provided on side surfaces 5A and 6A of the mask stage 5 and plate stage 6 along the Y direction, respectively, and side surfaces 5B and 6 of the mask stage 5 and plate stage 6 along the X direction.
Each of Bs is provided with a mirror 19C. Each interferometer 21-23 includes these mirrors 19A, 19B and 19
The mask 3 with the position of the photosensitive substrate 4 as a reference by irradiating each of C with a light beam and causing the reflected light beams to interfere with each other.
Measure the position of. Therefore, even if the scanning stage 7 is tilted during the exposure and the positional relationship of the mask 3 and the photosensitive substrate 4 with respect to the optical axis of the illumination light (with respect to the projection optical system 2) is changed, the position of the mask stage 5 is corrected to a predetermined position. Therefore, it is possible to prevent the scanning stage 7 from tilting and the distorted pattern image being transferred onto the photosensitive substrate 4.

Positioning and exposure operations by the exposure apparatus 1 having the above configuration will be described. First, at a position where the scanning stage 7 is away from the projection optical system 2 (the position shown in FIG. 1), the mask 3 is placed on the mask stage 5 by the mask loading mechanism, and the biasing pad 12 is set to the biasing position. Then, the mask 3 is sandwiched. Next, the scanning stage 7 is moved to the positions of the alignment microscopes 9 and 10 to measure the position of the pre-alignment mark 11 marked on the mask 3 and the nozzles 16A, 17A and 18A.
To supply compressed air through the ventilation holes 16, 17 and 18 to form a gas layer between the chuck surfaces of the mask 3 and the mask stage 5 and the mask 3 and the biasing pad 12.
Here, the amount of compressed air supplied is determined by the biasing spring 1 of the biasing pad 12.
Set appropriately considering the biasing force of 4. Mask 3 here
Based on the position measurement value of the pre-alignment mark 11 marked on the
The mask 3 is pre-aligned by driving B and moving the mask stage 5.

That is, by moving the pre-alignment shafts 15A and 15B up and down by the pre-alignment shaft drive unit 15 to rotate the mask 3, and by moving the mask stage 5 in parallel with the mask surface 3A of the mask 3, The pre-alignment mark 11 of the mask 3 is aligned with the reference position of the exposure apparatus 1 set in the alignment microscopes 9 and 10. After the pre-alignment of the mask 3 is completed, the compressed air is shut off and the ventilation holes 16 and 1
7 is switched to a vacuum source and a vacuum is drawn, and the mask 3 is fixed to the mask stage 5 by suction. With this, the pre-alignment of the mask 3 is completed, the scanning stage 7 is moved to the original rotating position, and the photosensitive substrate 4 is placed on the mask stage 5.

Next, fine alignment marks marked on the mask 3 and the photosensitive substrate 4 are simultaneously measured by the alignment microscopes 9 and 10, and the mask stage 5 is moved with respect to the plate stage 6, whereby the mask 3 and The photosensitive substrate 4 is aligned (hereinafter referred to as fine alignment). At this time, the amount of rotation of the mask pattern is suppressed below a certain value with respect to the neutral position of the mask stage 5 by the mask pre-alignment described above.

Further, since the fine alignment mark position of the photosensitive substrate 4 is accurately formed with respect to the outer side of the photosensitive substrate 4, the rotation amount of the fine alignment mark when the photosensitive substrate 4 is installed is small and the fine alignment mark is small. The rotation amount of the mask stage 5 caused by the alignment is determined by the interferometers 21 to 21.
It is less than or equal to the measurement allowable value of 23 (1 ['] or less). Therefore, when performing fine alignment, it is possible to prevent malfunction of the interferometers 21 to 23, so that the position of the mask stage 5 can be accurately detected.

When the fine alignment is finished, the mask 3 is illuminated, the mask 3 is projected onto the photosensitive substrate 4 through the projection optical system 2, and the mask 3 and the photosensitive substrate 4 are moved by the scanning stage 7. The original image pattern formed (or drawn) on the mask 3 is exposed on the photosensitive substrate 4 by moving along the guide 8 in the Y direction and scanning the projection field 2A of the projection optical system 2.

According to the above construction, since the pre-alignment axes 15A and 15B for pre-alignment of the mask 3 are provided on the mask stage 5 so as to support the lower side of the mask 3, fine alignment is achieved. Prior to this, since the rotational position of the mask 3 can be pre-aligned on the mask stage 5 to a certain value or less, even if the mask stage 5 is misaligned during fine alignment or during exposure, the interferometer 21 ~ 23
The position of the mask stage 5 based on the position of the photosensitive substrate 4 can be accurately detected. In addition, since the mask 3 is placed on the mask stage 5 with the in-plane direction of the mask 3 facing the direction of gravity, the mask 3 can be prevented from bending due to gravity.

Further, according to the above-described structure, the rotation amount of the mask 3 can be corrected on the mask stage 5 even when the patterning accuracy with respect to the outer side of the mask 3 is poor. Pre-alignment can be done accurately. Further mask stage 5
When pre-aligning the mask 3 above, compressed air is supplied between the mask 3 and the mask stage 5 and the mask 3 and the urging pad 12 to reduce the resistance when the mask 3 moves. The mask stage 5 and the mask stage 5 can be easily pre-aligned, and the position can be smoothly aligned even with a small drive device.

In the above embodiment, the photosensitive substrate 4
Although the case where the interferometers 21 to 23 are used as the position detecting means for detecting the position of the mask 3 based on the position of the above, the present invention is not limited to this, and the position of the mask 3 with respect to the photosensitive substrate 4 is detected. If possible, other position detecting means may be used.

Further, in the above embodiment, the photosensitive substrate 4
The case where the position of the mask 3 is detected on the basis of the position of is described, but the present invention is not limited to this, and the scanning stage 7
You may make it detect the relative position of the mask 3 and the photosensitive substrate 4 on the basis of.

In the above embodiment, the case where the pre-alignment shafts 15A and 15B are provided on the mask stage 5 has been described, but the present invention is not limited to this, and the mask 3 is pre-aligned with the mask stage 5. If possible, pre-alignment axes 15A and 15B
May be provided in another place.

In the above embodiment, the case where the mask stage 5 and the plate stage 6 are integrally placed on the scanning stage 7 and scanned is described, but the present invention is not limited to this, and the mask stage 5 and Plate stage 6
The mask stage 5 and the plate stage 6 may be synchronously scanned by other means as long as they can be synchronously scanned.

[0031]

As described above, according to the present invention, the mask and the photosensitive substrate are arranged so as to oppose each other so that the in-plane direction of the mask and the photosensitive substrate are in the direction of gravity, and the lower side of the mask is supported. After the mask is moved in the holding surface of the mask stage means by the adjusting means to align the mask and the mask stage means, the mask and the photosensitive substrate are aligned, so that Since the distortion can be prevented and the malfunction of the position detecting means can be prevented even when the mask and the photosensitive substrate are aligned with each other, it is possible to realize an exposure apparatus which can realize highly accurate exposure.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing details when the exposure pad according to the embodiment of the present invention is broken along the biasing pad and the pre-alignment axis.

[Explanation of symbols]

1 ... exposure device, 2 ... projection optical system, 2A ... projection field, 3 ... mask, 3A ... mask surface, 4 ... photosensitive substrate, 5 ... mask stage, 5A, 5B ... mask stage Side, 6 ... Plate stage, 6A, 6B ...
... side of plate stage, 7 ... scanning stage, 8 ...
… Guide, 9,10 …… Alignment microscope, 11 ……
Pre-alignment mark, 12 ... Energizing pad, 13 ...
... bias pad drive unit, 14 ... bias spring, 15 ... pre-alignment shaft drive unit, 15A, 15B ... pre-alignment shaft, 16, 17, 18 ... vent hole, 16A, 17
A, 18A ... Nozzle, 19A, 19B, 19C ... Mirror, 21-23 ... Interferometer.

Claims (2)

[Claims] 1. The entire surface of the mask is exposed on the photosensitive substrate by scanning a mask and a photosensitive substrate, which are arranged so as to face each other so that the in-plane direction is the direction of gravity, with respect to the projection optical system. In an exposure apparatus, a mask stage means for holding and moving the mask on a predetermined holding surface, a mask tilt preventing means for supporting the mask on the holding surface of the mask stage means, and a lower side surface of the mask. At the same time, by moving the mask in the holding surface of the mask stage means, position adjusting means for aligning the mask and the mask stage means, and a position for detecting the position of the mask stage means with respect to the photosensitive substrate. An exposure apparatus comprising: a detection unit. 2. The mask stage means and the mask tilt prevention means each have a ventilation hole on a surface facing the mask, and when the mask and the mask stage means are aligned with each other, they are compressed through the ventilation holes. By supplying air, a layer of gas is formed between the mask and the mask tilt prevention means and the mask and the mask stage means, and after the alignment of the mask and the mask stage means is completed, 2. The exposure apparatus according to claim 1, wherein the mask is attracted to the holding surface of the mask stage means by drawing a vacuum through a ventilation hole of the mask stage means.