JPH1010746A - Aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a time necessary for exposure/transfer and to improve a throughput, as for an aligner. SOLUTION: The aligner 1 is provided with an illuminating optical system 3 for forming a luminous flux L1 emitted from a light source 2 to a prescribed shape and illuminating an original plate 4 on which a circuit pattern is formed, and a projection optical system 8 for projecting a luminous flux L2 transmitted through the original plate 4 to a photosensitive substrate 7. In this case, the original plate 4 is held by a rotary stage 5 capable of correcting the relative rotational deviation between the original plate 4 and the photosensitive substrate 7, besides, the illuminating optical system 3 includes rotating means 35 and 36 for rotating the luminous flux with the prescribed shape for illuminating the original plate 4 so as to correct the rotational deviation with reference to the exposure area on the original plate 4. Thus, the structure of a stage for placing the photosensitive substrate 7 is simplified and made light in weight, and also the positional deviation at aligning is easily corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, which is suitable for use, for example, when producing a liquid crystal panel for a liquid crystal display.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal panel used for a liquid crystal display is exposed to a circuit pattern drawn on a mask (reticle) on a photosensitive substrate (hereinafter, referred to as a plate) having a surface coated with a photoresist by an exposure apparatus. And make it. In the exposure transfer step, prior to the exposure transfer, it is necessary to first perform alignment (hereinafter referred to as alignment) between the reticle and the plate transferred onto the stage of the exposure apparatus by the substrate transfer system. In this case, the xyz direction and θ between the plate and the reticle conveyed on the stage
The relative displacement in the (rotation) direction is corrected by fine-adjusting the stages of each layer in a four-layer structure stage capable of fine movement in the xyz direction and the θ direction, respectively, according to the amount of positional displacement.

[0003]

In recent years, as liquid crystal displays have become larger, individual panels forming the liquid crystal display, ie, plates forming the panels, have become larger. As described above, if the size of the plate is increased and the weight is increased, the stage itself on which the plate is mounted and moved also needs to be increased in size correspondingly, and the weight also increases. In fact, when exposing and transferring the circuit pattern of the reticle onto the plate in the exposure step, the weighted plate is moved at high speed by the above-described four-layer structure stage for alignment, and further, by the step-and-repeat method. Exposure processing is becoming more technically difficult in terms of stage strength and control method. For this reason, there is a problem that it becomes difficult to shorten the processing time required for plate alignment and exposure transfer in the exposure process accompanying the enlargement of the liquid crystal panel. SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to propose an exposure apparatus capable of reducing the weight of a stage on which a plate is mounted and shortening the processing time in a plate exposure process.

[0004]

According to the present invention, there is provided a mask (4) having a circuit pattern by shaping a light beam (L1) from a light source (2) into a predetermined shape.
In an exposure apparatus (1) including an illumination optical system (3) for illuminating a light source and a projection optical system (8) for projecting a light beam transmitted through the mask (4) onto a photosensitive substrate (7), the mask (4) Detecting means (30) for detecting a relative rotational displacement with respect to the photosensitive substrate;
A, 30B, 31A, 31B), a mask (4), and a rotating stage (5) for rotating the mask (4).
Rotating means (35, 36) for rotating a light beam of a predetermined shape for illuminating the mask (4) by rotating at least a part of the illumination optical system (3); and detecting means (30A, 30)
B, 31A, 31B) and a control unit (20) for controlling the rotating stage (5) and the rotating means based on the detection results.

[0005] Here, the mask (4) is held by a rotary stage (5) capable of correcting a relative rotational displacement between the mask (4) and the photosensitive substrate (7). The illumination optical system (3) includes rotation means (35, 36) for rotating a light beam of a predetermined shape for illuminating the mask to correct a rotational deviation with respect to the exposure area on the mask (4), thereby enabling the photosensitive substrate ( Stage (6) for placing 7)
Can be simplified and reduced in weight, and misalignment at the time of exposure can be easily corrected.

[0006]

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

In FIG. 1, reference numeral 1 denotes a step-and-repeat type exposure apparatus as a whole. Exposure light L 1 emitted from a light source 2 such as an ultra-high pressure mercury lamp is collected by an elliptical mirror 22. Thereafter, the light is reflected by the mirror 23 and enters the fly-eye lens system 25 via the input lens 24. A large number of secondary light source images are formed on the exit side of the fly-eye lens system 25, and the exposure light L1 from each of the secondary light source images is blindly arranged on a surface optically conjugate with the pattern surface of the reticle 4. 26.

The blind 26 has a rectangular opening, and the size of the rectangular opening is arbitrarily set in order to set an illumination area of the exposure light incident on the reticle 4. The blind 26 is rotatable about the optical axis by driving the actuators 35 and 36. The exposure light L1 that has passed through the rectangular opening of the blind 26 passes through the lens system 27,
An image is formed on the pattern surface of the reticle 4 via the mirror 28 and the main condenser lens 29. The reticle 4 has a reticle alignment mark RM for positioning the reticle 4 together with a circuit pattern, and is mounted on the reticle stage 5 by a suction mechanism (not shown).
Reticle stage 5 includes actuators 18, 19, and 20
Can move in the x, y, and θ directions.

The projection optical system 8 reduces the exposure light passing through the reticle 4 to, for example, １ ／ and projects the exposure light onto the plate 7. A search alignment mark for search alignment and an alignment mark PM for positioning the plate 7 are formed on the plate 7. The plate 7 is vacuum-sucked by a holder (not shown) on a z-stage 9 movably provided in the optical axis AX direction (z-direction). Also, between the z stage 9 and the base 12,
A y stage 11 movable in the y direction and an x stage 10 movable in the x direction are provided. Further, a reference member 13 having a reference mark and a movable mirror (not shown) are fixed to the y stage 11. The reference member 13 is set to be substantially the same height as the upper surface of the plate 7.

A moving mirror and a laser interference system (not shown)
The x-coordinate, y-coordinate, and rotational coordinate system of the plate 7 are constantly measured, and the measurement results are supplied to a control unit 15 and a stage drive system 16 described later. The stage drive system 16 controls driving of the z stage 9, the x stage 10, and the y stage 11. The exposure apparatus 1 has a TTR (Throug) for positioning the reticle 4 and the plate 7.
h The Reticle) Alignment System 30 (30A, 30
B) and TTL (Through The Lens) alignment system 31
(31A, 31B) are provided. In addition, TTR
The operation of alignment system 30 and TTL alignment system 31 will be described later.

The exposure apparatus 1 further includes a light projecting section 32A.
Sensor 32 composed of a light receiving portion 32B
Is provided. A slit plate for transmitting light is provided in the light projecting unit 32A, and a light beam transmitted through the slit plate is emitted from the light projecting unit 32A. The light beam emitted from the light projecting unit 32A obliquely enters the exposure surface on the plate 7 that intersects the optical axis AX. The slit-like luminous flux reflected by the exposure surface on the plate 7 enters the light receiving section 32B,
An image is formed on the B light receiver. The photodetector photoelectrically detects the received slit light beam.

The control unit 15 controls the entire exposure apparatus, and particularly controls the blind 26, the reticle stage 5,
Stage drive system 16, TTR alignment system 30, TT
The L alignment system 31 and the focus sensor 32 are controlled. Here, the operation of the TTR alignment system 30 and the TTL alignment system 31 under the control of the control unit 15 will be described. The control unit 15 controls a reticle alignment microscope (not shown) and a stage driving system 16 so that a reference mark of the reference member 13 provided on the y stage 11 and a reticle alignment mark RM formed on the reticle 4 are provided.
And observe. The control unit 15 finely adjusts the position of the reticle stage 5 so that the center of the reference mark matches the center of the reticle alignment mark RM.

Next, the control unit 15 controls the TTR alignment system 30 to obtain a phase difference from the diffraction light from the reference mark of the reference member 13 and the diffraction light from the reticle alignment mark RM. The amount of displacement between the reference mark of the member 13 and the reticle alignment mark RM is obtained.
The laser light emitted from the TTR alignment system 30 passes through a transparent portion (not shown) of the reticle 4 and then enters the reference mark of the reference member 13 via the projection lens 8. This displacement amount is stored in the storage unit in the TTR alignment system 30 as a target drive-in value. Control unit 15
Is the reticle stage 5 after reticle alignment is completed.
Is stored.

Next, the control unit 15 controls the TTL alignment system 31 to detect a search alignment mark on the plate 7 and performs a search alignment of the plate 7. Thereby, the control unit 15 can recognize the rough arrangement of each shot area of the plate 7. The control unit 15 controls the TTR alignment system 31 and the stage drive system 16 so that the reticle alignment mark RM
And an alignment mark RM on the plate 7 provided corresponding to the reticle alignment mark RM, and diffracted light from the reticle alignment mark RM and diffracted light from the alignment mark PM on the plate 7 are detected. And the phase difference between the reticle alignment mark RM and the alignment mark PM on the plate 7 is calculated.

In the processing system in the TTR alignment system 30, the target drive value stored in the storage unit in the TTR alignment system 30 and the reticle alignment mark RM
And a difference between the position deviation amount and the alignment mark PM on the plate 7 are output to the control unit 15. The control unit 15 sets the TT
The reticle stage 5 is set to x, y, θ based on the difference between the target drive-in value stored in the storage unit in the R alignment system 30 and the positional deviation amount between the reticle alignment mark RM and the alignment mark PM on the plate 7. Position in the direction.

Thus, the displacement of the relative position of the reticle 4 with respect to the plate 7 in the xyz and θ directions is TT
R alignment system 30 and TTL alignment system 31
And the control unit 15 calculates a correction amount based on the positional deviation amount of the relative position detected by the focus sensor 32,
The correction can be made by controlling the driving of the actuators 18, 19 and 20 and the stage drive system 16. In this case, the displacement of the reticle 4 in the x direction is corrected by driving the actuator 18 by pushing and pulling, and the displacement of the reticle 4 in the y direction is corrected by driving the actuators 19 and 20 in the same direction by the same amount. It has been made like that.

Further, θ between the reticle 4 and the plate 7
With respect to the relative rotational deviation in the direction, by pressing one of the actuators 19 and 20 and pulling the other in accordance with the amount of positional deviation, the reticle stage 5 is rotationally driven to correct the rotational deviation. Has been made. Thus, the relative rotational deviation between the reticle 4 and the plate 7 in the θ direction is corrected by the rotation control of the reticle stage 5, and the entire weight of the stage 6 is reduced by eliminating the θ stage from the stage 6. In addition, the alignment operation of the stage 6 and the exposure operation by the step-and-repeat method can be easily performed.

Here, regarding the rotational displacement in the θ direction, the rectangular illumination area of the light beam formed by the blind 26 and the reticle 4
The amount of rotation deviation between the exposure area of the reticle 4 and the exposure area of the reticle 4 may be deviated from the exposure area of the reticle 4 by rotating the reticle 4. in this case,
In addition to the rotation of the reticle 4, the control unit 15 further rotates the blind 26 in the θ direction with respect to the reticle 4 so that the rectangular illumination area illuminates the entire exposure area of the reticle 4 without omission. Has been made.

As described above, the actuator 26 for rotating the blind 26 is provided on the blind 26.
And 36 are installed, and the actuators 35 and 36 are driven in accordance with the correction amount for the reticle 4 which has exceeded the allowable rotation error of the plate 7 under the control of the control unit 15, so that the rotational deviation in the θ direction is obtained. Can be corrected so as to coincide with the exposure area of the reticle 4. This rotation deviation correction in the θ direction is performed by rotating the reticle stage 5 so that the final position control of the illumination area is performed. Therefore, the position control by the rotation of the blind 26 may be roughly approximated. Can easily be performed at a high speed, and the throughput in the exposure transfer of the plate 7 can be improved.

In the above configuration, the alignment and exposure steps under the control of the control unit 15 when exposing and transferring the circuit pattern formed on the reticle 4 onto the plate 7 will be described according to the xyθ position control sequence shown in FIG. I do. First, in step SP1, the plate 7 is transferred to the exposure apparatus 1 by a transfer system (not shown), placed on the z-stage 9 (loading), and vacuum-adsorbed (step SP2).

The control unit 15 detects the relative positions of the plate 7 and the reticle 4 vacuum-adsorbed on the z stage 9 in the xyθ directions by the TTR alignment system 30 and the TTL alignment system 31 as described above (step). SP3). Here, the control unit 15 determines xyθ based on the relative position between the reticle 4 and the plate 7 from the position information from the TTR alignment system 30 and the TTL alignment system 31.
The amount of displacement in the direction is calculated, and the amounts of correction in the x, y, and θ directions are calculated (step SP4). The control unit 15
In step SP5, a correction amount is calculated from the rotational deviation in the θ direction which is fed back, and the reticle stage 5 is rotated in the θ direction by pushing and pulling the actuators 19 and 20 based on the correction amount, thereby correcting the rotational deviation. I do.

Here, regarding the rotational deviation in the θ direction, the rectangular illumination area of the light beam formed by the blind 26 and the reticle 4
A large amount of rotational deviation occurs between the reticle 4 and the exposure area of the reticle 4 when the reticle 4 is rotated. in this case,
The control unit 15 rotates the blind 26 with respect to the reticle 4 via the actuators 35 and 36 in accordance with the correction amount in the θ direction in addition to the rotation of the reticle 4. Thereby, the reticle 4 in the rectangular illumination area by the light flux of the exposure light L1 is
Can be corrected with respect to the exposure region.

When the alignment of the plate 7 placed on the z-stage 9 and the reticle 4 in the θ direction is completed, the control unit 15 uses the correction amounts in the x and y directions calculated in SP4. The circuit patterns formed on the reticle 4 surface on the plate 7 are sequentially
Exposure transfer is performed (step SP6). This gives xy
The θ position control sequence ends. The correction of the positional deviation by the xyθ position control sequence can be executed according to the set alignment mode, such as once or several times for each processing of one plate, or for each single exposure.

According to the above configuration, when the rectangular illumination area of the light beam irradiated on the exposure area of the plate 7 has a rotational deviation in the θ direction, the rectangular illumination area is obtained from the TTR alignment system 30 and the TTL alignment system 31. The controller 15 calculates a correction amount from the relative rotational deviation amount of the reticle 4 and the plate 7 in the θ direction, and drives and controls the actuators 19 and 20 based on the correction amount, thereby moving the reticle stage 5 by θ. By rotating in the direction, the rotational deviation can be corrected. As described above, the relative rotational deviation between the reticle 4 and the plate 7 in the θ direction is corrected by controlling the rotation of the reticle stage 5, so that the θ stage does not have to be provided on the plate 7 side. As a result, the weight can be reduced, so that the alignment operation and the step-and-repeat operation can be performed at a high speed even for a relatively large plate.

Here, when the rotational deviation of the reticle 4 with respect to the plate 7 in the θ direction is large, and the rotation of the reticle 4 is controlled, the illumination area of the exposure light L1 with respect to the exposure area of the reticle 4 shifts. The control unit 15 can further correct the rotational deviation by rotating the blind 26 in the θ direction with respect to the reticle 4 and make the rectangular illumination area coincide with the exposure area of the reticle 4. As a result, the rotational deviation of the reticle 4 with respect to the plate 7 in the θ direction is
The rotation can be easily corrected by controlling the rotation of the blind 26. In this case, in the control unit 15, since the final correction of the rotational deviation of the illumination area in the θ direction is performed by the rotation of the reticle stage 5, the rotation control of the blind 26 may be roughly to some extent. Thereby, the alignment can be performed at a high speed in the exposure apparatus 1, and the throughput when exposing and transferring the circuit pattern to the plate can be improved.

In the above embodiment, the exposure light L1
When the amount of rotation deviation between the rectangular illumination area due to the rotation of the reticle 4 and the exposure area of the reticle 4 exceeds a rotation error that can be corrected by controlling the rotation of the reticle 4, the rotation deviation of the rectangular illumination area is caused by rotating the blind 26. Has been described, but the present invention is not limited to this.
For example, by rotating at least a part of the illumination optical system 3, the rotation deviation of the rectangular illumination area may be corrected.

Further, in the above-described embodiment, the case where the rotational deviation in the xyzθ direction is corrected has been described. However, the present invention is not limited to this.
The present invention can also be applied to the case of correcting the displacement in the θ direction. Further, in the above-described embodiment, a case has been described in which the displacement of the rectangular illumination area for illuminating the reticle 4 is corrected in the step-and-repeat type exposure apparatus. However, the present invention is not limited to this, and the present invention is not limited to this. The present invention can also be applied to the case of correcting the displacement of the scanning light beam in the θ direction.

Further, in the above-described embodiment, the case where the circuit pattern is exposed and transferred to the liquid crystal panel has been described. However, the present invention is not limited to this, and may be applied to, for example, the one where the circuit pattern is exposed and transferred to a semiconductor device. .

[0029]

As described above, according to the present invention, an illumination optical system for illuminating a mask having a circuit pattern by shaping a light beam from a light source into a predetermined shape, and projecting a light beam transmitted through the mask onto a photosensitive substrate. In an exposure apparatus having a projection optical system, a mask is held by a rotating stage capable of correcting a relative rotational displacement between the mask and the photosensitive substrate,
Furthermore, by including in the illumination optical system rotation means for rotating the light beam of a predetermined shape to illuminate the mask to correct the rotational deviation with respect to the exposure area on the mask, the stage for correcting the rotational deviation is not provided, The structure of the stage on which the photosensitive substrate is mounted can be simplified and reduced in weight, and the rotational deviation during exposure can be easily corrected. Thus, an exposure apparatus capable of improving the throughput in exposure transfer of the photosensitive substrate by controlling the drive of the stage at high speed can be realized.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing a position control sequence in an xyθ direction.

[Explanation of symbols]

1 exposure apparatus, 2 light source, 3 illumination optical system, 4
Reticle, 5 reticle stage, 7 plate, 8 projection optical system, 9 z stage, 10 x
Stage, 11 ... y stage, 12 ... base, 13
... Reference member 15, 15 control unit 16, stage drive system 18, 19, 20, 35, 36 actuators 23, 28 reflecting mirror 26 blind 30
... TTR alignment system, 31 ... TTL alignment system, 32 ... Focus and leveling sensor.

Claims (3)

[Claims] 1. An exposure system comprising: an illumination optical system for shaping a light beam from a light source into a predetermined shape to illuminate a mask having a circuit pattern; and a projection optical system for projecting a light beam transmitted through the mask onto a photosensitive substrate. In the apparatus, detecting means for detecting a relative rotational shift between the mask and the photosensitive substrate, a rotating stage for mounting the mask and rotating the mask, and rotating at least a part of the illumination optical system A rotation unit configured to rotate the light beam of the predetermined shape that illuminates the mask; and a control unit configured to control the rotation stage and the rotation unit based on a detection result of the detection unit. Exposure apparatus. 2. The exposure apparatus according to claim 1, wherein said control means controls a rotation amount of said rotation means according to a rotation amount of said rotation stage. 3. The illumination optical system according to claim 1, wherein said illumination optical system includes a blind mechanism for shaping a light beam from said light source into a predetermined shape, and said rotating means rotates said blind mechanism. 3. The exposure apparatus according to 2.