JPH04235558A - Exposure device - Google Patents

Abstract

PURPOSE:To obtain an exposure device suitable for exposing a large substrate to form a pattern thereon by providing means for removing the displacement between a substrate and a mask. CONSTITUTION:The displacement amount Xp of movement in X direction and the displacement amount Yp of movement in Y direction of a substrate 25 relative to a mask 31, both of which are found by a length measuring machine, are input to a CPU 37. The CPU 37 corrects the displacement amounts Xp, Yp input from the length measuring machine and the corrected values are input as drive signals to a drive control portion 36. The drive control portion 36 drives an X-stage motor 21 and a Y-stage motor 17 in response to the drive signals from the CPU37 so that the displacement amounts Xp and Yp become 0. Therefore the substrate 25 and the mask 31 opposite each other in Z direction are prevented from being displaced relative to each other in the X and Y directions.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus particularly suitable for exposing a pattern onto a large substrate.

0002

[Prior Art] Exposure devices include pro-miximity type exposure devices that expose a mask and substrate in close proximity with a gap of several tens of microns, stepper type exposure devices that expose a large substrate in small sections using a small mask, and masks. A reflective mirror type projection exposure apparatus is known, which has an optical system between the substrate and the substrate and exposes the substrate all at once using arcuate illumination.

[0003] In the above-mentioned promiximity type exposure apparatus, the larger the substrate, the more difficult it is to set the gap, and the resolution is as low as 10 to 30 microns because it depends on the gap. The above-mentioned stepper type exposure apparatus has a high resolution and can handle large substrates, but has a poor throughput and requires surface splicing between each exposure pattern, resulting in deterioration of the exposed pattern at the surface splicing portion.

On the other hand, the reflection mirror type projection exposure apparatus is suitable for exposing large substrates because it does not have the problems of the proximity type exposure apparatus and the stepper type exposure apparatus. FIG. 6 shows the basic configuration of a reflection mirror type projection exposure apparatus. That is, 1 in the figure is a mask. This mask 1 is irradiated with arcuate slit-shaped illumination light L. The illumination light L transmitted through this mask 1 is incident on the first reflection surface 2a of the reflection mirror 2 and is reflected in a substantially perpendicular direction. A concave mirror 3 is disposed in the direction in which this illumination light L is reflected. The illumination light L reflected by the concave mirror 3 is reflected by the convex mirror 4, then reflected by the concave mirror 3 again, and then reflected by the second reflective surface 2b of the folding mirror 2. The illumination light reflected by this second reflective surface 2b illuminates the substrate 5. Thereby, the pattern of the mask 1 is projected onto the substrate 5.

In the reflective mirror type projection exposure apparatus having such a configuration, in order to project the entire pattern of the mask 1 onto the substrate 5, after aligning the mask 1 and the substrate 5,
They must be moved in the same direction at the same time. Therefore, the mask 1 and the substrate 5 are held on the same stage, and this scanning stage is driven. However, when the scanning stage is driven by a drive mechanism, it is inevitable that the scanning stage will twist (for example, yawing) with respect to the driving direction and a direction perpendicular to the driving direction. A deviation occurs between one end and the other end in the direction. In other words, a misalignment occurs between the mask 1 provided at one end of the scanning stage and the substrate 5, and the pattern of the mask 1 transferred to the substrate 5 is distorted.

In order to compensate for the movement accuracy of the scanning stage, there is a system in which the scanning stage is guided by an aerostatic bearing, and the bearing pressure is varied to ensure the movement accuracy of the scanning stage. However, with the method of controlling air pressure using aerostatic bearings, since air is compressible, not only is it difficult to perform detailed control accurately, but the control of one bearing also affects other bearings. (axis interference), there is a limit to accuracy improvement.

[0007]

[Problems to be Solved by the Invention] As described above, in conventional exposure apparatuses, driving the scanning stage causes a misalignment between the mask and the substrate, and this misalignment causes distortion and magnification in the pattern transferred to the substrate. It was inevitable that errors would occur.

The present invention was made based on the above circumstances, and its purpose is to eliminate the misalignment between the mask and the substrate caused by driving the scanning stage, and to improve the transfer accuracy of the mask pattern. It is an object of the present invention to provide an exposure apparatus that can measure improvements in performance.

[0009]

[Means for Solving the Problems] The present invention includes a scanning stage, a first drive mechanism that drives the scanning stage in a predetermined direction, and a drive direction of the scanning stage driven by the first drive mechanism. A first holding part provided at one end in the orthogonal direction to hold the substrate, a second holding part provided at the other end to hold the mask, and a second holding part provided between the substrate and the mask to hold the substrate; an optical means for guiding the illumination light to the substrate; and a second optical means for driving at least one of the substrate or the mask on the scanning stage in a direction orthogonal to the driving direction of the scanning stage or in at least one direction.
and the relative displacement amount between the substrate and the mask in a direction perpendicular to the driving direction of the scanning stage or at least in one direction, which is caused by the scanning stage being driven by the first driving mechanism. It is characterized by comprising a measuring means for measuring, and a control means for driving and controlling the second driving mechanism so that there is no relative deviation between the substrate and the mask according to the measured value from the measuring means. do.

0010

[Operation] In the above configuration, when a relative shift occurs between the substrate and the mask due to the scanning stage being driven, the shift is measured by the measuring means, and the measurement is performed according to the measured value. The drive mechanism No. 2 is driven to remove the above deviation.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the structure of an exposure apparatus according to an embodiment of the present invention. This exposure apparatus is equipped with a scanning stage 11. The scanning stage 11 is formed in the shape of a hollow rectangular parallelepiped with openings on both sides and the top in the longitudinal direction, and aerostatic pressure bearings 12 each having a substantially U-shaped cross section are installed at both ends in the longitudinal direction of the bottom surface. It is provided along the width direction. These aerostatic pressure bearings 12 are slidably inserted in a non-contact state into a pair of guide bodies 13 arranged in parallel and spaced apart from each other. That is, the scanning stage 11
is supported by the pair of guide bodies 13 by air pressure in a non-contact state.

A driving screw 14 is provided between the pair of guide bodies 13 and parallel to the guide bodies 13. This drive screw 14 has a pair of receiving portions 15 at both ends (only one is shown).
The middle part is screwed to a connecting part (not shown) provided on the lower surface of the scanning stage 11, and the other end is connected to the main motor 16 constituting the first drive mechanism. There is. Drive screw 14
is rotationally driven by the main motor 16. Thereby, the scanning stage 11 is connected to the pair of guide bodies 13.
driven along. The driving direction of the scanning stage 11 along the guide body 13 is defined as the X direction.

On the inner surface of one side wall 11a of the scanning stage 11 in a direction orthogonal to the driving direction of the main motor 16, a first Y stage motor 17 is provided to drive the scanning stage 11 in the height direction (this direction is Y).
A first Y stage 18 is provided with one side slidably joined to the first Y stage 18, which is driven in a direction (direction). An X stage 19 is provided with one side of the X stage 19 slidably joined to the other side of the first Y stage 18 . This X
The stage 19 is operated by the X stage motor 21 to
The scanning stage 11 is driven in the X direction perpendicular to the driving direction of the Y stage 18 , that is, in the same direction as the scanning stage 11 is driven by the main motor 16 . This X
On the other side of the stage 19, there is a Z tilt stage 22 that is minutely driven by a drive source (not shown) in the Z direction perpendicular to the plane formed by the Y direction and the X direction to adjust the focus. It is provided. On the other side of the Z tilt stage 22, a first θ table 23 is provided with one side joined to the first θ table 23, which serves as a first holding part and is rotatable in the θ direction with a rotation center axis perpendicular to this plane. It is being This first θ table 23 is rotationally driven in the θ direction by a first θ motor 24. A large substrate 25 is suctioned and held on the other side of the θ table 23 by means such as vacuum suction, and a pattern of a mask 31 to be described later is transferred onto this substrate 25.

A second Y stage 27 driven in the Y direction by a second Y motor 26 is provided on the outer surface of the other side wall 11b of the scanning stage 11, with one side joined to the second Y stage 27. A second θ table 29 serving as a second holding portion is provided on the other side of the second Y stage 27 and is rotationally driven in the θ direction by a second θ motor 28 . The mask 31 on which a predetermined pattern is formed is held on the other side of the θ table 29 by means such as vacuum suction. the second θ table 29;
The other side wall 11b of the second Y stage 27 and the scanning stage 11 has an opening 32 through which light passes (an opening 32 of the second θ table 29 (only shown) are drilled.

A trapezoidal cross section is formed between the longitudinal center portion of the scanning stage 11, that is, between the substrate 25 held on the first θ table 23 and the mask 31 held on the second θ table 29. No, a folding mirror 33 having first and second reflecting surfaces 33a and 33b formed on both sides, respectively, is disposed. The first reflecting surface 33a of this folding mirror 33 is provided with illumination light L having a short wavelength, such as g-line or i-line, whose cross section is formed into an arcuate slit shape to irradiate almost the entire length of the mask 31 in the height direction (Y direction). is the above mask 3
1 and enters. The illumination light L reflected by the first reflective surface 33a is reflected by a concave mirror 34 disposed opposite to the folding mirror 33. A convex mirror 35 is disposed between the concave mirror 34 and the folding mirror 33. The illumination light L reflected by the concave mirror 34 is reflected by the convex mirror 35, and then reflected by the concave mirror 34 again to reach the second reflective surface 33b of the folding mirror 33.
is incident on the substrate 25 held on the first θ table 23. Thereby, the pattern of the mask 32 is transferred onto the substrate 25.

The above-mentioned folding mirror 33, concave mirror 34 and convex mirror 35 are mounted on the scanning stage 1.
They are fixedly provided to a fixed part (not shown) so as not to move in conjunction with the movement of the parts 1 and 1, so that the distance between them facing each other is always kept constant.

The main motor 16, the first Y stage motor 17, the X stage motor 21, and the first θ motor 2
3. The second Y motor 26 and the second θ motor 28 are connected to a drive control section 36, and are operated in response to a drive signal from the drive control section 36. A CPU 37 as a setting section is connected to the drive control section 36, and a drive signal is output from the drive control section 36 in response to a signal from the CPU 37.

When the scanning stage 11 is driven in the X direction by the main motor 16, the amount of deviation in the X direction between the substrate 25 and the mask 31 caused by the rotation of the scanning stage 11 around the Y axis. (hereinafter referred to as yawing deviation amount) and drive screw 14 (X
The amount of deviation (hereinafter referred to as rolling deviation amount) between the substrate 25 and the mask 31 along the Y direction, which is caused by rotation around the substrate axis), is measured by an optical measurement device 38 shown in FIG. In FIG. 2, the positional relationship between the substrate 25 and the mask 31 is reversed compared to that in FIG. 1 in order to make the measurement state easier to understand.

That is, the optical measuring device 38 has a laser head 41 installed at one end of the scanning stage 11 in the longitudinal direction. The laser beam R output from this laser head 41 is changed in course by a first reflector 42 in a direction parallel to the longitudinal direction of the scanning stage 11 . The laser beam R whose course has been changed is reflected upward in the vertical direction by the first beam splitter 43 at a position facing the side surface of the Z chilled stage 22 along the Y direction.
1 and the light R2 transmitted in the straight direction.

The light R1 reflected by the first beam splitter 43 is split by the second beam splitter 44 into a first reflected light R12 that is reflected in the horizontal direction and a first transmitted light R13 that is transmitted in the vertical direction. be done. The first reflected light R12 enters the first X interferometer 45. The first reflected light R12 emitted from the interferometer 45 enters the first X mirror 46 provided on the side surface of the Z chilled stage 22 along the Y direction. The first reflected light R12 reflected by the first X mirror 46 is received by the first X receiver 47 via the first X interferometer 45. Thereby, the amount of displacement of the Z chilled stage 22 in the X direction, that is, the coordinate Xp of the substrate 25 in the X direction is measured by optical interference, and the measured value is input to the length measuring device 48.

The first transmitted light R13 passes through the second reflector 5.
1 and reflected in the horizontal direction to the first Y interferometer 5.
2. The first transmitted light R13 emitted from the first interferometer 52 is transmitted to the Z chilled stage 2.
The first Y mirror 5 provided on the upper end surface along the X direction of 2
3. The first reflected by this first Y mirror 53
The transmitted light R13 is transmitted through the first Y interferometer 52.
The light is received by the first Y receiver 54 via. As a result, the Y-direction coordinate Yp of the substrate 25, which is the amount of displacement of the Z chilled stage 22 in the Y-direction, is measured, and the measured value is input to the length measuring device 48.

The light R2 transmitted through the first beam splitter 43 is reflected vertically upward by the third reflector 55 at a position corresponding to one side surface of the second Y stage 26 along the Y direction. Light R reflected by the third reflector 55
2 is split by the third beam splitter 56 into a second reflected light R21 that is reflected in the horizontal direction and a second transmitted light R22 that is transmitted in the vertical direction.

The second reflected light R21 enters the second X interferometer 57. The second reflected light R12 emitted from the interferometer 57 is reflected by a second X
The light is incident on the mirror 58. The second reflected light R12 reflected by the second X mirror 58 is received by the second X receiver 59 via the second X interferometer 57. As a result, the X-direction coordinate Xm of the mask 31, which is the amount of displacement of the second Y stage 26 in the X-direction, is measured, and the measured value is input to the length measuring device 48.

The second transmitted light R22 passes through the fourth reflector 6.
1, and the second Y interferometer 6 is reflected at a position corresponding to the upper end surface of the second Y stage 26.
2. The second transmitted light R22 emitted from this interferometer 62 is transmitted to the X
The light is incident on the second Y mirror 63 provided on the upper end surface along the direction. The second transmitted light R22 reflected by the second Y mirror 63 is received by the second Y receiver 64 via the second interferometa 62. Thereby, the amount of displacement of the second Y stage 26 in the Y direction of the mask 3
The Y-direction coordinate Ym of 1 is measured, and the measured value is input to the length measuring device 48.

The length measuring device 48 has a substrate 25 and a mask 31.
The amount of relative shift between the coordinates in the X direction and the Y direction is determined. That is, the relative displacement amount ΔXp of the substrate 25 with respect to the mask 31 in the X direction is (ΔXp = Xm
-Xp ), and the amount of deviation ΔYp in the Y direction is (
ΔYp = Ym - Yp).

The substrate 25 determined by the length measuring device 48
Relative shift amount ΔXp in the X direction with respect to the mask 31
The amount of deviation ΔYp in the Y direction is input to the CPU 37. The CPU 37 corrects the deviation amounts ΔXp and ΔYp from the length measuring device 48 using correction coefficients Ax and Ay described later, and the corrected values are inputted to the drive control section 36 as a drive signal. This drive control section 36
Based on the drive signal from U37, the X stage motor 21 and the first Y stage motor 17 are moved by the above deviation amount Δ.
Drive so that Xp and ΔYp become zero. Thereby, the substrate 26 and the mask 31 facing each other in the Z direction
This makes it possible to eliminate relative deviations between the X direction and the Y direction.

The correction coefficients Ax and Ay are coefficients for correcting measurement errors caused by misalignment of each component of the optical measurement device 38. Therefore, the driving amounts ΔXp' and ΔYp' are driven to correct the deviation between the X direction and the Y direction in which the substrate 25 is actually driven.
is ΔXp'=Ax ・ΔXp ΔYp' =Ay ・ΔYp

[0029] The above correction coefficients Ax and Ay are
For example, the coordinates of the substrate 25 and the mask 31 in the X direction and the Y direction may be measured in a state where the amount of drive of the scanning stage 11 in the X direction is 0, and the displacement amount at that time may be set to be 0. Note that the length dimensions of the first Y mirror 53 and the second Y mirror 63 are set longer than the distance over which the illumination light L illuminates the substrate 25 along the X direction. Next, the operation of the exposure apparatus having the above configuration will be explained with reference to FIG.

First, after setting the correction coefficients Ax and Ay in the X and Y directions in the CPU 37, the substrate 25 and the mask 31 are aligned. In other words, if the mask 31 is positioned at a predetermined position by driving the second Y stage motor 27 and the second θ motor 28, the first Y stage motor 27 and the second θ motor 28 are
The substrate 25 is aligned with the mask 31 by driving the stage motor 17, the first X-stage motor 21, and the 1-liter θ motor 24.

When the alignment between the substrate 25 and the mask 31 is completed, the illumination light L is incident from the mask 31, the main motor 16 is driven, and the scanning stage 11 is moved along the X-axis direction by the drive screw 14. Driven. Thereby, the pattern of the mask 31 is changed to the folding mirror 33, the concave mirror 34, and the convex mirror 35.
The substrate 25 is irradiated via an optical means consisting of
The pattern of the mask 31 is exposed onto this substrate 25.

When the scanning stage 11 is driven in the X-axis direction, the length measuring device 48 of the optical measuring device 38 measures the amount of relative displacement between the substrate 25 and the mask 31 in the X direction and the Y direction. Board 2 measured by length measuring device 48
5 and the mask 31 in the X direction and the Y direction coordinate deviation ΔX
When p, ΔYp are measured, the deviation amount ΔXp, ΔY
p is corrected by correction coefficients Ax and Ay. and,
Based on the corrected deviation amounts ΔXp' and ΔYp', the first Y stage 18 and the X stage 19 holding the substrate 25 are driven by the drive control unit 36 to adjust the deviation amount Δ.
Xp' and ΔYp' are removed.

That is, the scanning stage 11 is
By driving along the axial direction, yawing or rolling occurs in the scanning stage 11, and even if a deviation occurs between the substrate 25 and the mask 31 in the X direction and the Y direction, the deviation occurs and the same is avoided at the same time. is the optical measuring device 38
is detected by the drive control unit 36 via the CPU 37.
is corrected by driving. Therefore, the pattern of the mask 31 can be transferred onto the substrate 25 without any deviation.

FIG. 3 is an explanatory diagram of the occurrence of yawing. That is, when the scanning stage 11 is tilted at an angle θy with the Y-axis as the center of rotation with respect to the driving direction along the L means that the irradiation position on the substrate 25 is shifted by ΔXy. Therefore, this ΔXy becomes the yawing amount, and this yawing amount ΔXy can be obtained as (ΔXy = l·θy).

Although not shown, the amount of rolling is a deviation that occurs when the scanning stage 11 is tilted in the Y direction with the X axis as the center of rotation, and can be determined in the same manner as the amount of yawing. Also, each stage's X, Y
The direction in which the axis is measured is not specified.

On the other hand, by repeating the exposure many times, the substrate 25
Since thermal deformation such as shrinkage occurs in the image, it is necessary to correct the pattern deviation due to the shrinkage, that is, to correct the magnification. FIGS. 4A to 4C explain the principle of magnification correction in the X-axis direction. That is, while the illumination light L irradiates from one end of the mask 31 to the other end, at each X coordinate,
The coordinates of the substrate 25 in the X direction are corrected based on a predetermined magnification correction amount. As a result, even if there is a deviation of ΔXm between one end of the mask 31 and one end of the substrate 25 as shown in FIG. 4(a), at the time of FIG.
Since the relative deviation ΔXm at one end is corrected, even if the substrate 25 shrinks due to repeated exposure,
Pattern deviations in each exposure process are corrected.

The amount of magnification correction in the X direction in this embodiment is performed as follows. That is, before starting each exposure process, the amount of deviation due to thermal deformation between the substrate 25 and the mask 31 is measured, and the measured value is sent to the CPU 37 as the magnification correction amount.
is input. The CPU 37 divides and sets the magnification correction amount for each predetermined X coordinate. Each time the scanning stage 11 is driven to the predetermined X coordinate, the X stage motor 21 is
The substrate 25 is driven in the X direction and the magnification correction described above is performed.

Note that since the magnification correction in the Y direction is in the direction where the width of the substrate 25 is narrow, it is less necessary to correct it than in the X axis direction, but when performing magnification correction in that direction, the illumination light L Before entering the mask 31, an optical system (not shown)
All you have to do is enlarge or reduce it in the direction.

In this way, the illumination light L is corrected for the deviation between the yawing direction and the rolling direction that occurs as the scanning stage 11 is driven, and the magnification is corrected due to thermal deformation of the substrate 25, while the illumination light L is adjusted over the entire length of the substrate 25 along the X direction. When irradiated with , the driving of the scanning stage 11 is stopped and the pattern exposure of the mask 31 onto the substrate 25 is completed.

[0040] In the above embodiment, yawing correction,
To perform rolling correction and magnification correction, the board 25 is
Although the mask 31 is driven not only in the Y direction but also in the X direction, the mask 31 can be driven in the X direction and the Y direction to perform each of the above corrections. Alternatively, the above correction may be performed by driving both the substrate 25 and the mask 31.

Furthermore, in the above embodiment, rolling correction and magnification correction are performed in addition to yawing correction.
The exposure apparatus of the present invention may be configured as long as it can perform at least one of each correction. For example, in the case of only yawing correction, it is sufficient that the substrate 25 is driven only in the X direction, and the optical measuring device 38 only needs to be able to measure the amount of deviation between the substrate 25 and the mask 31 in the X direction.

[0042]

As described above, according to the present invention, the deviation occurring between the substrate and the mask in the direction perpendicular to the driving direction of the scanning stage or in at least one direction is measured, and the deviation is measured in accordance with the measured value. Since at least one of the mask or the substrate is driven to perform exposure while removing the deviation, the pattern of the mask can be accurately exposed without causing deviation of the substrate.

[Brief explanation of the drawing]

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 schematic configuration diagram of an optical measuring device in the same embodiment.

FIG. 3 is an explanatory diagram of the yawing correction principle in the same embodiment.

FIGS. 4(a) to 4(c) are explanatory diagrams of the principle of magnification correction in the same embodiment.

FIG. 5 is a flowchart in the same embodiment.

FIG. 6 is an explanatory diagram of the principle of a reflection mirror type projection exposure apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11...Scanning stage, 16...Main motor (1st drive mechanism), 21...X stage motor (2nd drive mechanism), 25...Substrate, 31...Mask, 33, 34, 35
...Optical means, 36... Drive control section, 37... Setting section (CPU
), 38...Optical measuring device.

Claims (1)

[Claims] 1. A scanning stage, a first driving mechanism for driving the scanning stage in a predetermined direction, and a scanning stage provided at one end in a direction orthogonal to the driving direction of the scanning stage driven by the first driving mechanism. a first holding part that holds the substrate and a second holding part that is provided on the other end side and holds the mask; and a second holding part that is provided between the substrate and the mask and guides illumination light incident on the mask to the substrate. an optical means, a second drive mechanism that drives at least one of the substrate or the mask on the scanning stage in a direction orthogonal to the drive direction of the scanning stage or in at least one direction, and the scanning stage is driven by the first drive mechanism. a measuring means for measuring the amount of relative deviation between the substrate and the mask in a direction orthogonal to the driving direction of the scanning stage, or in at least one direction, which is caused by being driven by the scanning stage; and control means for driving and controlling the second drive mechanism so that there is no relative displacement between the substrate and the mask.