JP3378076B2 - Exposure apparatus and exposure method - Google Patents

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 an exposure method used in the manufacture of semiconductor devices and liquid crystal display devices.

[0002]

2. Description of the Related Art A proximity exposure method (proximity exposure method) is a method in which a glass substrate or wafer coated with a photosensitizer (hereinafter simply referred to as a substrate) and a mask are supported in close proximity to each other, and illumination light is emitted from above the mask. Is an exposure method in which the mask pattern is transferred to a photosensitive agent by irradiating with. Compared with the projection exposure method, this exposure method does not require a complicated lens system or a highly accurate stage, so it is easy to reduce the cost, and compared with the contact exposure method, since the mask and the substrate do not come into direct contact with each other, the peeling of the photosensitive agent It has the excellent feature that defects due to However, the resolution of the transferred image by the proximity exposure largely depends on the distance between the mask and the substrate, and the minimum line width ds of the transferred image is ds = √ (2λ where λ is the wavelength of the light source and g is the distance between the mask and the substrate.
g), for example, using a mercury lamp as the light source,
In order to resolve a line width of about m, the mask and the substrate must be close to each other by about 30 μm, while the waviness of the substrate is generally about 10 to 20 μm, so the distance between the mask and the substrate is extremely small. It must be adjusted precisely. Conventionally, as this method, the distance between the mask and the substrate is measured at multiple points other than the mask pattern, and the substrate surface is aligned with the approximate plane obtained from the measurement results, or scanning local illumination is used as the illumination for exposure. A method has been considered in which the gap between the mask and the substrate at the portion irradiated with the illumination light is measured by a laser reflection type gap sensor and adjusted to a predetermined value.

A conventional proximity exposure apparatus will be described below with reference to the drawings. FIG. 4 shows a first conventional example of a proximity exposure apparatus. In FIG. 4, 1 is a stand, 2
Is a Y-axis guide fixed to the mount 1, 4 is a Y stage slidably attached to the Y-axis guide 2 in the Y direction, 3 is an X-axis guide fixed to the Y stage 4, and 5 is an X-axis guide 3. An X stage slidably mounted in the X direction, 6 is a local illumination unit fixed to the X stage 5, 8 is an optical fiber whose one end is connected to the local illumination unit 6, 11 is a mercury lamp, 1
Reference numeral 2 is a reflecting mirror that collects light from the mercury lamp 11, 7 is a lens fixed in the local illumination unit 6, and 25 is an X-axis guide 3 on the X axis.
A sensor X stage that is slidably attached in a direction and moves in synchronization with the X stage 5, and 40 is a light projecting laser element 40a and a light receiving element 4 fixed to the sensor X stage 25.
0b and gap measuring means, 13 is X on the gantry 1.
XYθ stage mounted slidably on Y plane, 1
Reference numeral 5 is a piezo actuator connected to the XYθ stage 13, 14 is a Z stage which is mounted on the piezo actuator 15 and moves in the Z direction, 31 is a gap adjusting means composed of the piezo actuator 15 and the Z stage 14, and 26 is Z. A quartz chuck fixed on the stage 14, 20 is a substrate chucked and held by a quartz chuck 26, 1
6 is fixed to the gantry 1 at one end and the mask chuck 18 at the other end.
A mask frame connected to the mask frame, 21 a mask sucked and held by a mask chuck, 23 a mask pattern formed on the mask 21, and 17 connected to the mask frame 16 at one end and slidable in the X direction at the other end. Alignment scope 19
Is a bracket attached to, and 37 is a gap setter 3.
2, a controller 33 and a piezo driver 34, and one end is a control unit electrically connected to the gap measuring unit 40 and the other end electrically connected to the piezo actuator 15. The operation of the conventional exposure apparatus configured as described above will be described below.

In the illumination of the conventional example, the light emitted from the mercury lamp 11 is condensed by the reflecting mirror 12 and is guided to one end of the optical fiber 8 and the luminous flux emitted from the other end is reflected by the lens 7 in the local illumination section 6.
The local illumination unit 6 is held in close proximity to the substrate 20 and the alignment scope 1 is adjusted.
The X stage 5 is placed above the mask 21 aligned by
By the Y stage 4 and their driving means (not shown), they can be freely moved in the XY plane. Then, the gap between the mask 21 and the substrate 20 in the illumination light irradiation portion is measured by the laser reflection type gap measuring means 40, and the output signal thereof is compared with the set value of the gap setter 32 in the controller 33, and the deviation signal is detected by the piezo driver 34. Entered in. The piezo driver 34 sends a control signal to the piezo actuator 15 according to the deviation signal to drive the Z stage 14 to drive the substrate 2
It is possible to bring 0 and the mask 21 close to each other at a set predetermined distance, and by scanning and exposing the entire area of the mask 21 with the local illumination unit 6, a high-resolution transferred image can be obtained over the entire exposed area.

Next, a second conventional example will be described with reference to the drawings. FIG. 5 shows a second conventional example of the proximity exposure apparatus. In FIG. 5, 1 is a mount, 52 is a mount attached to the mount 1, the mercury lamp 11, the reflecting mirror 12, and the fly-eye lens 5
An illumination system support member that supports 3 and the condenser lens 54, 13
Is an XYθ stage slidably mounted on the pedestal 1, 15 is arranged so as not to be on the same straight line in the XY plane, one end is attached to the XYθ stage 13, and the other end is Zαβ
Three piezo actuators mounted on the stage 51, 51 are Zαβ stages that can be moved by the piezo actuator 15 in the rotation α direction about the Z direction and the X axis and the rotation β direction about the Y axis, and 58 is the piezo actuator 15 and the Zαβ stage. An interval adjusting means composed of 51, 55 a substrate chuck mounted on the Zαβ stage 51, 20 a substrate suction-held on the substrate chuck 55, 22 an opaque thin film formed on the substrate 20, 16
Is a mask mount attached to the mount 1, 56 is a sensor support attached to the mask mount 16 slidably in the Y direction, and 50 is attached to the sensor support 56 so as not to be on the same straight line in the XY plane. Gap sensor, 17 is a bracket mounted on the mask mount 16, 19 is an alignment scope mounted on the bracket 17 so as to be slidable in the X direction, 18 is a mask chuck mounted on the mask mount 16, and 21 is a mask chuck 18. , 23 is a mask pattern formed on the mask 21, 23 is a mask pattern formed on the mask 21, 57 is a gap measurement window provided on the mask 21, 37 is a gap setter 32, a controller 33 and a piezo driver 34 The other end of the gap sensor 50 is the piezo actuator 1
5 is a control means electrically connected.

The operation of the conventional exposure apparatus configured as described above will be described below. The light beam emitted from the mercury lamp 11 is condensed on the fly-eye lens 53 by the reflecting mirror 12, is uniformized by the fly-eye lens 53, and is then adjusted to a parallel light beam by the condensing lens 54. On the other hand, the substrate 20 sucked and held by the substrate chuck 55 is masked by the gap sensors 50 provided at three locations above the gap measurement window 57.
The distance from 1 is measured. Then, the measured value is input to the controller 33 together with the set value of the gap setter 32, and the controller 33 processes these and outputs a command signal to the piezo driver 34.
Is a control signal corresponding to the command signal. Piezo actuator 1
5, the Zαβ stage 51 is driven to adjust the distance between the substrate 20 and the mask 21. After that, the substrate 20 and the mask 2 are aligned using the alignment scope 19 and the XYθ stage 13.
1 and align the alignment scope 19 to X
Direction, the sensor support member 56 is driven in the Y direction to retract the gap sensor 50 from above the mask 21, and the illumination light is irradiated from above the mask 21 to perform exposure.

[0007]

However, according to the first conventional example, a thin film which is opaque to a laser beam (a metal thin film is often formed on a glass substrate) is formed on the substrate 20. If formed, the gap measuring means 40 cannot measure the distance between the mask 21 and the substrate 20. Further, when the gap measuring means 40 is arranged above, a thin film which is opaque to the laser beam (a metal thin film is often formed on the mask) is formed on the mask 21. Therefore, the gap measurement means 40 cannot measure the distance. Furthermore, when a non-translucent thin film is formed on both the substrate 20 and the mask 21, there is a problem in that the gap cannot be measured at any position of the gap measuring means 40. there were.

On the other hand, according to the second conventional example, the gap between the mask 21 and the substrate 20 at the points other than the measurement points by the gap sensor 50 is inaccurate, and it is difficult to obtain high resolution over the entire exposure area. Had a point.

Therefore, the present invention solves these problems, and improves the entire exposure area even when a thin film opaque to a laser beam or the like is formed on one or both of the substrate and the mask. An object of the present invention is to provide an exposure apparatus and an exposure method capable of performing exposure with a resolution.

[0010]

In order to achieve the above object, the present invention is a proxy for supporting a substrate and a mask in opposition to each other and irradiating the mask with illumination light to expose and transfer the mask pattern onto a photosensitive layer on the substrate. In the Miti exposure apparatus, scanning local illumination means, and mask surface measuring means arranged on the mask side for scanning in synchronization with the local illumination means and detecting the reference surface height of the mask in the irradiation portion of the local illumination means. A reference surface measuring means arranged on the substrate side for scanning in synchronization with the local illuminating means and detecting a reference surface height of the substrate in the irradiation portion; and a mask in the illuminating portion at a measurable position at a predetermined location. Gap measuring means for measuring the distance to the substrate, distance adjusting means for adjusting the distance between the mask and the substrate, mask surface measurement value by the mask surface measuring means, and substrate surface by the substrate surface measuring means The gap between the mask and the substrate is indirectly obtained based on the mask surface measurement value and the substrate surface measurement value by calibrating the difference between the measured value and the gap measurement value by the gap measuring means. And a control means for controlling the interval adjusting means based on the value obtained in step 1 and the set value.

In the above exposure apparatus, it is preferable from the viewpoint of simplification of the structure that the mask surface measuring means and the substrate surface measuring means form a pair to constitute the gap measuring means.
Furthermore, if these are composed of laser reflectometers,
It is preferable from the viewpoint of improving the measurement accuracy.

In order to achieve the above object, the present invention provides a proximity exposure method in which the exposure apparatus having the above-mentioned configuration is used to irradiate the mask with illumination light to transfer the mask pattern onto the photosensitive layer on the substrate by exposure. Alternatively, the substrate is provided with a light-transmitting gap measuring window, and the gap measuring means is used to measure the gap between the mask and the substrate using the gap measuring window.

[0013]

According to the present invention, the measurement value of the mask surface measuring means and the measurement value of the substrate surface measuring means are previously calibrated (calibrated) with the measurement value of the gap measuring means.
As a result, even when an opaque thin film is formed on one or both of the substrate and the mask, the distance between the mask and the substrate can be indirectly measured by the mask surface measuring means and the substrate surface measuring means, and accurate distance adjustment can be performed. Is possible. Further, since it is possible to accurately adjust the interval at each scanning position in the exposure area, it is possible to perform high resolution exposure over the entire exposure area.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a diagram showing an embodiment of an exposure apparatus according to the present invention, FIG. 2 is a partially enlarged view for explaining the calibration function of the present embodiment, and FIG. 3 is a perspective view of a mask of the present embodiment as seen from the pattern side. It is a figure.

In FIG. 1, 1 is a mount, 2 is a Y-axis guide fixed to the mount 1, 4 is a Y stage mounted on the Y-axis guide 2 slidably in the Y direction, and 3 is fixed to the Y stage 4. X-axis guide, 5 is an X stage slidably attached to the X-axis guide 3 in the X direction, 6 is a local illumination unit fixed to the X stage 5, and 9 is a projection laser element fixed to the X stage 5. A laser reflection type mask surface measuring means composed of 9a and a light receiving element 9b, 8 an optical fiber whose one end is connected to the local illumination unit 6, 11 a mercury lamp, 12 a reflecting mirror for collecting the light of the mercury lamp 11, 7 A lens fixed in the local illumination unit 6, 25 is attached to the X-axis guide 3 slidably in the X-direction, and is an X-stage for sensor that moves in synchronization with the X-stage 5, 10 is fixed to the X-stage for sensor 25 Laser A reflection type substrate surface measuring means having a light projecting laser element 10a and a light receiving element 10b, 13 is an XYθ stage slidably mounted on the gantry 1 in the XY plane, and 15 is connected to the XYθ stage 13. 3 or more piezoelectric actuators, 14 is a Z stage which is mounted on the piezoelectric actuator 15 and moves in the Z direction, 31 is the piezoelectric actuators 15 and Z
A space adjusting means constituted by the stage 14, 26 is a quartz chuck fixed on the Z stage 14, 20 is a substrate sucked and held by the quartz chuck 26, and 22 is a non-contact film such as a chromium whole thin film formed on the substrate 20. A translucent thin film, 16 is a mask mount having one end fixed to the mount 1 and the other end connected to the mask chuck 18, 21 is a mask sucked and held by the mask chuck 18, and 23 is a mask formed on the mask 21. A pattern, 24 is a translucent gap measuring window opened in a part of the mask pattern 23, 17 is attached to the alignment scope 19 so that one end is connected to the mask mount 16 and the other end is slidable in the X direction. Bracket, 37
Is composed of a gap setter 32, a controller 33 and a piezo driver 34, one end of which is electrically connected to the mask surface measuring means 9 and the substrate surface measuring means 10 and the other end of which is electrically connected to the piezo actuator 15. It is a means. In this embodiment, the mask surface measuring means 9 and the substrate surface measuring means 10 form a pair to constitute a gap measuring means for measuring the distance between the mask 21 and the substrate 20. An exposure method using the exposure apparatus configured as above will be described below.

In the illumination of this embodiment, the light emitted from the mercury lamp 11 is condensed by the reflecting mirror 12 and is guided to one end of the optical fiber 8 and the luminous flux emitted from the other end is reflected by the lens 7 in the local illumination unit 6.
The collimated light beam is adjusted to irradiate parallel light beams, and the local irradiation unit 6 is held in close proximity to the substrate 20.
The X stage 5 is placed above the mask 21 aligned by
By the Y stage 4 and their driving means (not shown), they can be freely moved in the XY plane.

To adjust the distance between the substrate 20 and the mask 21, first, as shown in FIG. 2, the X stage 5 and the Y stage 4 are moved above the gap measuring window 24, and the mask surface measuring means 9 is used to move the upper surface of the substrate thin film 22. P is measured (measurement value B),
Further, the lower surface Q of the substrate thin film 22 is measured by the laser reflection type substrate surface measuring means 10 (measurement value C), and the difference B-C between the two is measured.
Is stored as an offset value F in the controller 33. That is, the mask surface measuring means 9 and the substrate surface measuring means 10
The offset value F is measured by the gap measuring means consisting of a pair of and and is stored in the controller 33. Then, as shown in FIG. 1, the X stage 5 is moved to a portion other than the calibration window 24 and the mask surface measuring means 9 is moved.
The lower surface R of the mask 21 is measured (measured value A) by the controller 3 together with the measured value C measured by the substrate surface measuring means 10.
3, the distance between the mask 21 and the substrate 20 is obtained by A-C-F, this value is compared with the set value D of the gap setter 32, and the deviation signal is sent to the piezo driver 34.
The piezo driver 34 can send a control signal corresponding to the deviation signal to the piezo actuator 15 to drive the Z stage 14 to bring the substrate 20 and the mask 21 close to each other at a set predetermined interval, and by exposing in this state, high resolution is achieved. Can be exposed. Such a space adjustment is performed at each scanning position, and the space between the mask 21 and the substrate 20 is adjusted over the entire surface.

In this embodiment, the gap between the mask 21 and the substrate 20 was measured using the gap measuring window 24 provided on the mask 21 side, but the gap measuring window provided on the substrate 20 side was used. Further, the gap measuring means is the mask surface measuring means 9 and the substrate surface measuring means 10.
You may provide independently from and.

[0019]

According to the present invention, even when an opaque thin film is formed on one or both of a substrate and a mask, an accurate interval can be provided at each scanning position of the exposure region, so that the exposure region can be formed. High resolution exposure is possible on the entire surface.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged view for explaining a calibration function.

FIG. 3 is a perspective view of a mask.

FIG. 4 is a sectional view showing a first conventional example of a proximity exposure apparatus.

FIG. 5 is a sectional view showing a second conventional example of the proximity exposure apparatus.

[Explanation of symbols]

6 Local illumination means 9 Mask surface measuring means 9, 10 Gap measuring means 10 Board surface measuring means 20 substrates 21 mask 24 Gap measurement window 31 Interval adjustment means 37 Control means

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-326369 (JP, A) JP-A-7-201710 (JP, A) JP-A-6-5486 (JP, A) JP-A-5- 59998 (JP, A) JP-A-3-38025 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 7/20

Claims (4)

(57) [Claims] 1. A proximity exposure apparatus in which a substrate and a mask are supported in opposition to each other, and the mask is irradiated with illumination light to expose and transfer the mask pattern onto a photosensitive layer on the substrate. The mask surface measuring means arranged on the mask side for scanning in synchronization with the illuminating means and detecting the reference surface height of the mask in the illuminated portion of the local illuminating means; A reference plane measuring means arranged on the side of the substrate for detecting the reference plane height of the substrate, a gap measuring means for measuring the distance between the mask and the substrate in the illuminated portion at a predetermined measurable position, and a mask. The gap between the gap measuring means and the gap adjusting means for adjusting the distance to the substrate, the difference between the mask surface measured value by the mask surface measuring means and the substrate surface measured value by the substrate surface measuring means. By calibrating with a measurement value, based on the mask surface measurement value and the substrate surface measurement value, the distance between the mask and the substrate is indirectly obtained, based on the indirectly obtained value and the set value. An exposure apparatus comprising: a control unit that controls the interval adjustment unit. 2. The exposure apparatus according to claim 1, wherein the mask surface measuring means and the substrate surface measuring means are paired to constitute a gap measuring means. 3. The mask surface measuring means and the substrate surface measuring means are constituted by a laser reflection type measuring device.
The exposure apparatus described. 4. A proximity exposure method of irradiating a mask with illumination light to expose and transfer a mask pattern onto a photosensitive layer on a substrate using the exposure apparatus according to claim 1, wherein the mask or the substrate is transparent. An exposure method characterized in that a gap measuring window is provided, and the gap between the mask and the substrate is measured by the gap measuring means using the gap measuring window.