JPH07283115A - Scanning aligner - Google Patents

Abstract

PURPOSE:To stably expose a mask pattern on a plate at high resolution and accuracy without depending on guide accuracy of a scanning stage and without being affected by disturbance. CONSTITUTION:A pattern on a mask 2 is exposed on a plate 5 through projection optical systems 3a to 3e corresponding to equal magnification and erecting image, and the mask 2 and the plate 5 are scanned to the projection optical systems 3a to 3e by a carriage 6 integrally. A pitching amount of the carriage 6 is detected by differential interferometers 13A, 14A, 15A and a position of the mask 2 is finely adjusted through fine movement actuators 7 to 9 according to the pitching amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use in exposing a large-area pattern onto a photosensitive substrate, such as a semiconductor device or a liquid crystal display substrate manufactured by a photolithography process. The present invention relates to a mold exposure apparatus.

[0002]

2. Description of the Related Art For example, a mask (photomask or reticle) is used to manufacture a large-sized liquid crystal panel (liquid crystal display substrate) or a large-area semiconductor device with high throughput.
The upper slit-shaped (rectangular, arc-shaped, etc.) illumination area is illuminated, the mask is scanned in the short side direction with respect to the illumination area, and photoresist is applied to the exposure area conjugate with the illumination area. Attention has been focused on a scanning type exposure apparatus that sequentially exposes a pattern on a mask onto a plate by synchronously scanning a plate (a glass plate or a semiconductor wafer).

In such a scanning type exposure apparatus, an illumination optical system and a projection optical system are fixed to a predetermined base, and a mask and a plate are placed on a scanning stage movably arranged with respect to the base. It had been. Then, by scanning the mask and the plate in the predetermined scanning direction with respect to the base via the scanning stage, the pattern of the mask is sequentially transferred onto the plate. In this case, if the tilt angle of the scanning stage with respect to the base changes during scanning exposure, the pattern exposed on the plate laterally shifts, and the resolution and accuracy of the pattern exposed on the plate deteriorate. for that reason,
The guiding accuracy of the scanning stage with respect to the base needs to be maintained at high accuracy.

[0004]

As described above, in the conventional scanning type exposure apparatus, the resolution and accuracy of the pattern exposed on the plate depended on the guide accuracy of the stage. In this regard, recently, with the high integration of liquid crystal panels and the like, it has been required to further improve the resolution and accuracy of the pattern exposed on the plate. However, if the guide accuracy of the scanning stage is further increased to improve the resolution and accuracy, the manufacturing cost of the entire apparatus becomes high, which is not practical.

Further, along with high integration, it is required to increase the area of a liquid crystal panel or the like. However, it is difficult to stably scan a large area mask and plate with high guiding accuracy, and the conventional scanning exposure method has a limit in the area of a pattern that can be exposed with high resolution and accuracy. Further, in order to maintain the guiding accuracy of the scanning stage with high accuracy, the scanning speed of the scanning stage cannot be increased so much, and it is difficult to improve the throughput of the exposure process.

Further, in the conventional method that depends on the guide accuracy of the scanning stage, the relative tilt angle of the scanning stage with respect to the base changes due to the vibration generated in, for example, the wafer loader system or the reticle loader system. In this case, the resolution or accuracy of the exposed pattern may be partially deteriorated, and the yield of manufactured liquid crystal display substrates or the like may be deteriorated. That is, there is an inconvenience that it is vulnerable to disturbance such as vibration.

In view of the above point, the present invention can stably expose a pattern of a mask on a plate with high resolution and accuracy without depending on the guiding accuracy of a scanning stage and without being affected by disturbance. An object is to provide a scanning type exposure apparatus.

[0008]

A scanning type exposure apparatus according to the present invention includes a mask (2) as shown in FIGS. 1 to 3, for example.
An illumination optical system (1a to 1d) that illuminates the upper pattern with an illumination region of a predetermined shape, and a light-sensitive substrate (W) that is an erect image with substantially equal magnification of the light flux that has passed through the pattern on the mask (2).
A projection optical system (3a to 3e) for projecting upward, a mask stage on which the mask is mounted and movable in the horizontal direction, and a photosensitive substrate stage on which the photosensitive substrate is mounted and movable in the horizontal direction are integrally formed. A scanning type exposure apparatus which holds a frame (6) that moves in a predetermined scanning direction with respect to the illumination area and sequentially exposes the pattern on the mask onto the photosensitive substrate. To 3e) tilt state detecting means (13A to 15A, 11) for detecting a relative tilt with respect to the frame (6), and the mask stage and the photosensitive substrate stage thereof based on the detection result of the tilt state detecting means. Adjusting means (7 to 9) for adjusting the position of at least one of the above.

In this case, an example of the inclination state detecting means is composed of a detected member (11) and detection members (13A to 15A) for detecting the inclination angle of the detected member, and the detected member is a frame ( 6). Further, it is desirable that the inclination state detecting means detects at least one of a pitching amount and a rolling amount of the frame (6) during the movement of the frame.

[0010]

According to the present invention, the relative inclination change between the frame (6) and the projection optical system (3a to 3e) generated during the scanning exposure is detected by the tilt state detecting means. Since the shift amount of the mask pattern on the photosensitive substrate (5) can be known from the posture change thus detected, the adjusting means (7 to 9) is used to correct the shift amount between the mask and the photosensitive substrate. Correct at least one position. As a result, the mask pattern is exposed on the photosensitive substrate by the scanning exposure method with high resolution and accuracy even if the frame (6) is tilted due to disturbance without depending on the guiding accuracy of the frame (6). .

Further, the adjusting means (7 to
As 9), for example, when a fine movement mechanism on the mask side is used, this fine movement mechanism can also serve as a fine movement stage used for alignment between the mask and the photosensitive substrate, which is performed at the time of normal exposure. Cost increase is suppressed. Further, when the tilt state detecting means is composed of a member to be detected and a member to detect the tilt angle of the member to be detected, and the member to be detected is provided in the frame (6), the frame (6) Is detected.

Further, when the tilt state detecting means detects at least one of the pitching amount and the rolling amount of the frame (6) which is moving, pitching or rolling occurs while the frame is moving. However, by correcting the lateral displacement of the mask pattern by the adjusting means, the resolution and accuracy of the mask pattern on the photosensitive substrate can be maintained high.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the scanning type exposure apparatus according to the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to a scanning exposure apparatus having a plurality of projection optical systems that project erect images at equal magnification. Figure 1
Shows a schematic configuration of the scanning exposure apparatus of the present embodiment,
In FIG. 1, illumination light emitted from a light source such as an ultra-high pressure mercury lamp is guided to five partial illumination optical systems 1a to 1e via a light guide or the like (not shown). The partial illumination optical systems 1a to 1e are each configured to include a fly-eye lens, a field stop, a condenser lens, and the like, and the illumination light emitted from the partial illumination optical systems 1a to 1e is masked via mirrors 1f to 1j, respectively. The different trapezoidal illumination areas M1 to M5 on 2 are illuminated with a uniform illuminance distribution.

The mask 2 is held on an upper stage 6a of a carriage 6 having a U-shaped cross section through a fine movement stage 10. The fine movement stage 10 passes through the fine movement actuators 7, 8 and 9 with respect to the carriage 6 in the X direction which is the scanning direction, the Y direction which is perpendicular to this X direction, and
It is supported so as to be finely movable in the rotation direction (θ direction). The mask 2 is finely moved with respect to the carriage 6 integrally with the fine movement stage 10. A displacement measuring function is added to each of the fine movement actuators 7 to 9, and the fine movement actuators 7 to 9 can push and pull the fine movement stage 10 by an instructed amount.

Illumination regions M1 to M5 on the mask 2 are divided into two columns set at a predetermined interval in the X direction which is the scanning direction, and three illumination regions M1, M3 and M5 are arranged in the first column, Two illumination areas M2 and M4 are arranged in the second row, and the oblique sides of the trapezoidal illumination areas M1 to M5 are arranged to overlap each other in the scanning direction. A plate 5 having a photoresist as a photosensitive substrate applied on a lower stage 6b of the carriage 6 through a predetermined holder (not shown).
Is held, and five projection optical systems 3a to 3e for projecting an erect image with equal magnification are respectively provided between the mask 2 and the plate 5.
Are fixed in the same arrangement as the illumination areas M1 to M5.
The Z axis is taken parallel to the optical axes of the projection optical systems 3a to 3e.

In this case, the patterns in the illumination areas M1 to M5 are respectively exposed as equal-magnification erect images on the trapezoidal exposure fields P1 to P5 on the plate 5 via the projection optical systems 3a to 3e. . The exposure fields P1, P3 and P5 in the first column and the exposure fields P2 and P4 in the second column on the plate 5 are arranged so that the hypotenuses of the trapezoids overlap in the scanning direction (X direction). Therefore, for example, an area exposed on one oblique side of the exposure field P1 and an area exposed on one oblique side of the exposure field P3 are overlapped and scanned at the oblique side of the exposure field P2. As a result, the integrated exposure amount after scanning exposure is made uniform over the entire surface of the plate 5.

As the projection optical systems 3a to 3e in this embodiment, for example, a projection optical system of a mirror projection type in which a concave mirror and a convex mirror are combined can be used. By driving the carriage 6 to integrally scan the mask 2 and the plate 5 in the X direction, the patterns in the pattern area 2a on the mask 2 are sequentially exposed on the shot area 5a on the plate 5.

FIG. 3 shows a simplified configuration of the optical system and the stage system of this embodiment. In FIG. 3, the partial illumination optical systems 1a to 1e of FIG. 1 are represented by the illumination optical system 1, and the projection optical system. 3a to 3e are represented by one projection optical system 3. In this case, the carriage 6 is mounted on the base 18 via a drive mechanism (not shown) so as to be driven in the X direction, and the illumination optical system 1 is fixed to the upper plate 19a of the column 19 planted in the base 18. The projection optical system 5 is fixed in the middle plate 19b. Then, a long movement stroke in the X direction is secured for the carriage 6 on the base 18,
Is scanned in the X direction so that the mask 2 and the plate 5 are scanned integrally with the carriage 6 with respect to the projection optical system 3.

Returning to FIG. 1, a movable mirror 11 is fixed to the end surface of the carriage 6 in the X direction, and a laser beam is emitted parallel to the movable mirror 11 from the laser light source 13A fixed on the base 18 of FIG. LB1 is being ejected. The laser beam LB1 is split into two laser beams LB1A and LB1B in the Z direction by the light beam splitting / combining prism 14A, enters the moving mirror 11, and the laser beams LB1A and LB1B reflected by the moving mirror 11 are split and combined. The light is combined by the prism 14A and is incident on the receiver 15A. The receiver 15A has two laser beams LB1.
The interference light of A and LB1B is photoelectrically converted.

In this case, the laser light source 13A, the beam splitting / combining prism 14A, the movable mirror 11, and the receiver 15A constitute a differential interferometer. Then, when the carriage 6 is pitched during scanning and the movable mirror 11 rotates about an axis parallel to the Y axis, the optical path length between the laser beams LB1A and LB1B incident on the receiver 15A is changed to cause interference. Since the phase of the stripe (or the frequency in the heterodyne interferometer) changes, the moving mirror 1 around the Y-axis is changed.
A rotation angle of 1 is detected. From the receiver 15A, the rotation angle of the movable mirror 11 around the Y axis (that is, the carriage 6
Angle signal .theta.Y corresponding to the pitching amount) is supplied to the arithmetic processing unit 20 of FIG.

Similarly, X is attached to the end surface of the carriage 6 in the Y direction.
The movable mirror 12 extending in the direction is fixed, and the rotation angle of the movable mirror 12 around the X axis is measured by a differential interferometer including a laser light source 13B, a beam splitting / combining prism 14B, and a receiver 15B. From the receiver 15B, the rotation angle of the movable mirror 12 around the X axis (that is, the carriage 6
The angle signal θX corresponding to the rolling amount of the above is supplied to the arithmetic processing unit 20 of FIG.

Further, in FIG. 1, Y is formed above the mask 2.
A pair of alignment microscopes AM1 and AM2 are arranged at predetermined intervals in the direction. Corresponding to this, the alignment marks 16A, 1 are formed near the pattern area 2a of the mask 2.
6B are formed, and alignment marks 17A, 17B, ... Are also formed in the vicinity of the shot area 5a of the plate 5. For example, before starting scanning exposure, the alignment microscope AM1 detects the amount of positional deviation between the alignment mark 16A on the mask 2 and the alignment mark 17A on the plate 5, and at the same time, the alignment microscope AM1.
2 detects the amount of misalignment between the alignment mark 16B on the mask 2 and the alignment mark 17B on the plate 5 so that the amount of misalignment falls within a predetermined allowable range, for example, in the X and Y directions of the mask 2. , And the position in the rotation direction (θ direction) are adjusted. This allows plate 5
The initial overlay accuracy of the pattern already formed on the pattern and the pattern to be exposed is improved.

Therefore, information on the amount of positional deviation detected by the alignment microscopes AM1 and AM2 is supplied to the arithmetic processing unit 20 of FIG. In FIG. 4, the arithmetic processing unit 20 indicates that the alignment microscope A has
Mask 2 from the information of the amount of positional deviation from M1 and AM2
Is calculated, and this correction amount is supplied to the mask stage controller 21. In response to this, the mask stage control device 21 drives the fine movement actuators 7 to 9 to drive the mask 2
Finely adjust the position and rotation angle of. Thereafter, the mask stage control device 21 scans the carriage 6 in the X direction at a predetermined speed to start the exposure by the scanning exposure method.

Next, when pitching or rolling (including the case where these occur simultaneously) occurs in the carriage 6 during scanning exposure, the angle signal θ from the receiver 15A.
Y or the angle signal θX from the receiver 15B, as shown in FIG.
The arithmetic processing unit 20 recognizes the pitching amount or rolling amount of the carriage 6. In FIG. 4, the carriage 6 is tilted, and the optical axis AX of the projection optical system 3 (actually, the projection optical systems 3a to 3e) is tilted relative to the mask 2 and the plate 5 by an angle Δθ. , The projection optical system 3 is at position 2
2 shows a state of being shifted. In this case, assuming that the pattern 20 on the mask 2 is exposed on the area 21 on the plate 5 when the projection optical system 3 is not tilted, if the optical axis AX is tilted by the angle Δθ, The exposure position of the pattern 20 on the mask 2 is displaced from the original exposure area 21 by δ. The shift amount δ is as follows.

Δ = L · sin Δθ (1) Therefore, if no correction is made, the resolution and accuracy of the exposed pattern will decrease and the pattern formed on the plate 5 by the previous steps. The overlay accuracy with Therefore, the mask stage control device 21 of FIG. 4 finely adjusts the position of the mask 2 in real time via the fine movement actuators 7 to 9 so as to cancel the shift amount δ. That is, in FIG. 2, the position of the mask 2 is finely adjusted so that the pattern 20 on the mask 2 is exposed on the region 21 on the plate 5. As a result, even if pitching or rolling occurs in the carriage 6, the resolution and accuracy of the pattern exposed on the plate 5 is maintained high, and the overlay accuracy is also maintained high.

In the present embodiment, the yawing of the carriage 6 and the displacement in the X, Y, or Z direction do not cause the shift of the exposure image, so that such displacement detection and control are unnecessary. is there. However, when the carriage 6 is displaced in the Z direction, it is normally in a defocused state, but this embodiment does not cause a problem because the projection optical systems 3a to 3e of equal magnification erect system are used. This is because the longitudinal magnification becomes 1 at the same magnification, so that when the plate 5 is displaced by ΔZ in the Z direction, for example, the conjugate relationship is maintained if the mask 2 is also displaced by ΔZ in the Z direction.

In the above embodiment, the attitude of the carriage 6 is detected by the differential interferometer, but the attitude of the carriage 6 may be detected by another detecting means such as an autocollimator. Further, although the projection optical system for projecting an erect normal image at the same magnification is used in the above-mentioned embodiment, for example, in a scanning type projection exposure apparatus using a projection optical system for projecting an inverted image at a reduction or enlargement magnification. The present invention also applies. Further, it goes without saying that it is also applied to a step-and-scan type exposure apparatus.

As described above, the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

[0029]

According to the present invention, since the exposure position of the mask pattern is finely adjusted according to the inclination of the frame (carriage) with respect to the projection optical system during scanning, it depends on the guiding accuracy of the frame. There is an advantage that the mask pattern can be stably printed on the photosensitive substrate with high resolution and accuracy without being affected by disturbance.

Further, since it is possible to use the adjusting means together with the adjusting mechanism for alignment which is already provided in the exposure apparatus, there is an advantage that the exposure apparatus can be constructed inexpensively and compactly. Further, according to the present invention, even if the entire apparatus is enlarged in order to expand the exposure range, the requirements for processing accuracy and assembling accuracy of the guide that serves as a guide for scanning exposure do not become strict. Further, if an attempt is made to set a large exposure range, the weight of the scanning unit may be increased and the frame or the like may be deformed. However, since the correction control including elastic deformation of each unit during scanning can be performed, the exposure pattern It is easy to deal with large area.

Further, the tilt state detecting means comprises a member to be detected and a detecting member for detecting the tilt angle of the member to be detected,
When the member to be detected is provided on the frame, the posture of the frame can be detected with a simple configuration. Further, when the tilt state detecting means detects at least one of the pitching amount and the rolling amount of the frame while the frame is moving, even if pitching or rolling occurs in the frame, the mask pattern shift can be prevented. .

[Brief description of drawings]

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

FIG. 2 is a conceptual diagram showing an error occurrence state when an inclination occurs between the carriage and the projection optical system in the embodiment.

FIG. 3 is a simplified side view showing the configuration of the stage system of the embodiment.

FIG. 4 is a block diagram showing a configuration of a control system of the embodiment.

[Explanation of symbols]

 1a to 1e Illumination optical system 2 Mask 3a to 3e Projection optical system 5 Plate 6 Carriage 7, 8, 9 Fine movement actuator 10 Fine movement stage 11, 12 Moving mirror LB1, LB2 Laser beam P1 to P5 Exposure field AM1, AM2 Alignment microscope M1 M5 illumination area

Claims (3)

[Claims] 1. An illumination optical system for illuminating a pattern on a mask with an illumination region having a predetermined shape, and a projection for projecting a light flux passing through the pattern on the mask on a photosensitive substrate as an erect image with substantially equal magnification. An optical system, a mask stage on which the mask is mounted and which is movable in the horizontal direction, and a photosensitive substrate stage on which the photosensitive substrate is mounted and which is movable in the horizontal direction are integrally held, and a predetermined area is provided for the illumination area. A frame that moves in the scanning direction of, and a scanning type exposure apparatus that sequentially exposes the pattern on the mask onto the photosensitive substrate, and detects a relative tilt of the projection optical system with respect to the frame. Means and adjusting means for adjusting the position of at least one of the mask stage and the photosensitive substrate stage based on the detection result of the tilt state detecting means. A scan type exposure apparatus. 2. The tilt state detecting means comprises a member to be detected and a detecting member for detecting an inclination angle of the member to be detected,
The scanning exposure apparatus according to claim 1, wherein the detected member is provided on the frame. 3. The tilt state detecting means detects at least one of a pitching amount and a rolling amount of the frame while the frame is moving.
Or the scanning type exposure apparatus according to 2.