JP3641320B2 - Shutter device used in exposure apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shutter device used in an exposure apparatus for transferring a pattern drawn on a photomask onto the substrate by irradiating light from the light source onto the photosensitive surface of the substrate through the photomask. It is related with the shutter apparatus which is arrange | positioned in the optical path of this light, and can operate | move so that this light may be interrupted | blocked. As such an exposure apparatus, for example, an apparatus that transfers and forms a pattern such as an electric circuit on a printed circuit board or a flat display glass substrate is known.
[0002]
[Prior art]
In a system in which light emitted from a light source (for example, a point light source such as a short arc lamp) is converted into a parallel light beam using a lens and a mirror, and exposure work is continuously performed using the parallel light beam, a shutter device is placed at any position on the optical path. And repeatedly opening and closing the shutter device. Shutter device types include a swing door type that rotates around an axis parallel to the light blocking surface, a slide type that moves within the light blocking surface, and a rotating blade type that rotates around an axis perpendicular to the light blocking surface. There is.
[0003]
Regardless of the type of shutter device, it is preferable to increase the opening / closing speed and control the exposure amount. For this purpose, the shutter device should be small and light. Therefore, it is general that the light from the light source is once condensed and the shutter device is provided near the focal point where the cross-sectional area of the light beam becomes small. This is because if the cross-sectional area of the light beam is reduced, the area of the light blocking surface of the shutter device can be reduced.
[0004]
However, when the beam converges and the cross-sectional area of the light beam decreases, the thermal energy per unit area increases. Due to this increased thermal energy, the light blocking surface of the closed shutter device is heated to a high temperature. In particular, in an exposure apparatus for a large substrate, a lamp with a large output (3 to 8 kw) is used, so the temperature of the light blocking surface of the shutter device may exceed 500 ° C.
[0005]
In order to cope with such a situation, an expensive refractory metal has been conventionally used as a material for the light blocking surface of the shutter device. Nevertheless, cracks occurred and oxidation was severe, and the life of the shutter device was short.
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive shutter device that can maintain a relatively long life even when it receives a converged light beam having high thermal energy and that does not lose its advantages of small size and light weight.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, according to the present invention, an exposure apparatus for transferring a pattern drawn on a photomask onto a substrate by irradiating light from a light source onto the photosensitive surface of the substrate through the photomask. The shutter device is disposed in an optical path of light from the light source and is operable to block the light, wherein the light blocking surface has an uneven shape. Is provided.
[0008]
The uneven shape may have a plurality of grooves parallel to each other.
[0009]
Furthermore, you may provide the apparatus for flowing air along the said some groove | channel.
[0010]
Each of the plurality of grooves may have a triangular cross section.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, a light source box 16, a fly-eye lens 6, a plane mirror 7, a curved mirror 8, and an exposure unit 10 are arranged in the frame 1 of the exposure apparatus. In the exposure box 16, for example, a light source 2 such as a short arc lamp, a condensing mirror (elliptical concave mirror) 3, and a flat mirror 4 are arranged. In the exposure unit 10, a photomask 11 on which a pattern is drawn and a substrate 12 on which the pattern is formed by exposure are arranged.
[0012]
The light emitted from the light source 2 is collected by the condenser mirror 3. The light reflected by the plane mirror 4 is focused near the fly-eye lens 6. The light that has become the parallel light beam 9 from the fly-eye lens 6 through the plane mirror 7 and the curved mirror 8 is exposed by the exposure unit 10.
[0013]
The shutter device 5 is disposed at a location where the cross-sectional area of the light beam is sufficiently small just before the focal point near the fly-eye lens 6. The shutter device 5 has a light blocking surface 13, and the light blocking surface 13 is oriented in a direction perpendicular to the optical axis of the light beam to be irradiated. The shutter device 5 of this embodiment is of a swing door type that rotates around the axis of a shaft 15 parallel to the light blocking surface 13, but is of other types (slide type, rotary blade type) as described above. A thing may be adopted. In FIG. 1, the shutter device 5 drawn by a solid line shows a “closed state”, and the shutter device 5 drawn by a two-dot chain line shows a “open state”.
[0014]
As shown in FIG. 2, a plurality of triangular grooves 17 are formed in parallel on the light blocking surface 13 of the shutter device 5. Such a shape can be formed by alternately bending the metal plates 18. The bent metal plate 18 can be attached to the frame 14 fixed to the shaft 15 by welding or screwing.
[0015]
In the illustrated embodiment, the cross section of the groove 17 is an equilateral triangle having an apex angle of 60 degrees. The light applied to the light blocking surface 13 when the shutter device 5 is closed is not a parallel ray as seen in FIG. 1, but the whole is averaged due to symmetry with respect to the optical axis perpendicular to the light blocking surface 13. Then, it irradiates at right angles with respect to the light blocking surface 13. When the groove 17 has a regular triangular cross section with an apex angle of 60 degrees, the light receiving area of the metal plate 18 in the region of the blocking surface 13 is 2 as compared with the case where the metal plate 18 has a flat shape. It will be understood geometrically that it is doubled. Therefore, the thermal energy of the light is halved per unit light receiving area, and the temperature rise of the metal plate 18 is greatly suppressed.
[0016]
The cross-sectional shape of the groove 17 may be a triangle other than a regular triangle. Further, the groove 17 may have a rectangular cross-sectional shape or a trapezoidal cross-sectional shape. Alternatively, the metal plate 18 may be bent so as to draw a waveform like a continuous sine curve to form a concavo-convex shape, whereby a plurality of parallel grooves 17 may be formed. In any case, an uneven shape that increases the light receiving area is formed on the light blocking surface 13 as compared with the conventional flat light blocking surface.
[0017]
The shutter device 5 according to the present invention may further include a device (not shown) for flowing cooling air along the groove 17. The ventilation by such a device can further suppress the temperature rise of the light blocking surface 13. When the cooling air is blown onto the light blocking surface 13 by such a device, the flow direction of the air is naturally restricted along the groove 17 and flows almost uniformly over the entire light blocking surface 13. Cool down.
[0018]
The concave / convex shape formed on the light blocking surface 13 does not have to form the groove 17 as described above as long as the light receiving area is increased as compared with the conventional flat light blocking surface.
[0019]
In addition, although the example in which the metal plate 18 is bent when forming the uneven shape on the light blocking surface 13 is shown, the uneven shape may be formed by other methods such as a shaving process.
[0020]
【The invention's effect】
In the shutter device according to the present invention, the light receiving surface has an uneven shape instead of the conventional flat surface, so that the light receiving area is increased compared to the flat light blocking surface. Therefore, the thermal energy of light per unit light receiving area is reduced, and the temperature rise of the light blocking surface is suppressed. As a result, a long life can be maintained compared to the conventional one. On the other hand, since the area of the region where the light beam can be blocked by the light blocking surface does not change, the shutter device can maintain the advantages of small size and light weight even though the light receiving area is increased, and the speed of opening and closing operation is impaired. I can't. Further, it is not necessary to use an expensive heat-resistant material, and it can be manufactured at a low cost.
[0021]
When the concavo-convex shape is a plurality of grooves arranged in parallel with each other and cooling air is allowed to flow through the grooves, the temperature rise of the blocking surface of the shutter device is further suppressed. Therefore, the shutter device can perform a reliable operation for a longer period of time.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing an example of an exposure apparatus incorporating a shutter device according to the present invention.
2A and 2B are diagrams showing an embodiment of a shutter device according to the present invention, in which FIG. 2A is a front view, FIG. 2B is a top view, and FIG. 2C is a side view.
[Explanation of symbols]
1 frame, 2 light source, 3 condenser mirror, 4 plane mirror, 5 shutter device, 6 fly-eye lens, 7 plane mirror, 8 curved mirror, 9 parallel light beam, 10 exposure part, 11 photomask, 12 substrate, 13 light blocking Surface, 14 frames, 15 axes, 16 light source box, 17 grooves, 18 metal plate.

Claims (2)

A shutter device used in an exposure apparatus for transferring a pattern drawn on a photomask onto the substrate by irradiating light from the light source onto the photosensitive surface of the substrate through a photomask, In a shutter device arranged in the optical path and operable to block the light,
The light blocking surface has an uneven shape that increases the light receiving area compared to a flat light blocking surface ,
The uneven shape has a plurality of grooves parallel to each other,
The shutter device further comprises a device for flowing air along the plurality of grooves . The shutter device according to claim 1 , wherein each of the plurality of grooves has a triangular cross section.

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