JP3601174B2 - Exposure apparatus and exposure method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exposure apparatus and an exposure method, and can be applied to, for example, exposing a large area pattern on a photosensitive substrate for manufacturing a liquid crystal display device.
[0002]
[Prior art]
Conventionally, when exposing a large area pattern to a photosensitive substrate, a partial pattern is repeatedly exposed until a desired area is reached. On the other hand, a photosensitive substrate for manufacturing a liquid crystal display device has recently been desired to have a large area. For this reason, it has been desired for an exposure apparatus to enlarge an exposure area per unit time. In order to enlarge the exposure area per unit time, a scanning exposure apparatus having a plurality of projection optical systems has been proposed.
[0003]
This scanning type exposure apparatus is provided with a plurality of illumination optical systems, and illuminates different small areas (illumination areas) on the mask with light beams emitted from the respective illumination optical systems. Incidentally, the illumination optical system of this scanning type exposure apparatus uses a field stop to shape a light beam emitted from a light source and having a uniform light amount through an optical system including a fly-eye lens or the like into a desired shape using a field stop. Illuminate the surface.
Subsequently, the scanning type exposure apparatus projects an image of the illuminated pattern on the mask onto a different projection area on the photosensitive substrate via each of the plurality of projection optical systems to form an image. This scanning type exposure apparatus synchronizes a mask and a photosensitive substrate, scans the illumination optical system and the projection optical system, and transfers the entire pattern region on the mask onto the photosensitive substrate.
[0004]
[Problems to be solved by the invention]
Incidentally, there is an appropriate value for the exposure amount of the resist when the pattern on the mask is transferred to the photosensitive substrate. The exposure amount is represented by the product of the illuminance of the light beam emitted from the light source and the exposure time, that is, the exposure amount = the exposure illuminance on the substrate surface × the exposure time. The illuminance of the light beam emitted from the light source increases and decreases in proportion to the luminance of the light source. The brightness of the light source is maximum at the beginning of use and decreases according to the use time.
For this reason, when the luminance of the light source is large, the scanning exposure apparatus described above needs to increase the scanning speed of the mask and the substrate in order to shorten the exposure time. On the other hand, when the luminance of the light source decreases, it is necessary for the above-described scanning exposure apparatus to reduce the scanning speed so as to obtain a constant exposure amount on the resist on the photosensitive substrate.
[0005]
However, the brightness of the light source is generally non-uniform due to manufacturing errors. The scanning speed of the mask and the substrate with respect to the illumination optical system and the projection optical system generally has an upper limit due to the characteristics of the control system. That is, there is a limit to shortening the exposure time by controlling only the scanning speed.
For this reason, if the luminance of the light source is too large to cope with the upper limit scanning speed, the difference between the exposure time at the upper limit scanning speed and the exposure time at the scanning speed required for proper exposure becomes an overexposure time. In addition, there has been a problem that the mask pattern cannot be accurately transferred to the photosensitive substrate.
[0006]
The present invention has been made in consideration of the above points, and even if the brightness of the light source is too large to adjust the exposure amount to an appropriate value only by controlling the scanning speed of the photosensitive substrate with respect to the illumination optical system, the photosensitive substrate It is an object of the present invention to propose an exposure apparatus and an exposure method capable of giving an appropriate exposure amount to a light source.
[0007]
[Means for Solving the Problems]
In order to solve this problem, a description will be given in association with FIG. 2 showing an embodiment. In the exposure apparatus according to claim 1, a plurality of luminous fluxes L6 to L8 respectively emitted from a plurality of ultra-high pressure mercury lamps 10 are provided. Are condensed by the light guide 14 and then divided by the light guide 14 to obtain a plurality of different illumination areas M1 to M5 on the mask on which the pattern is formed. It has an illumination optical system 2 for illuminating each, and a plurality of projection optical systems 4A to 4E arranged corresponding to the plurality of illumination regions M1 to M5, respectively. In an exposure apparatus that projects onto the photosensitive substrate 5 via each of the projection optical systems 4A to 4E, a plurality of shutters 1 that regulate the respective luminous fluxes L6 to L8 emitted by the plurality of ultrahigh-pressure mercury lamps 10 with an aperture ratio. And a light detection element 21 for detecting the illuminance of the light fluxes L1 to L5, and the respective aperture ratios of the plurality of shutters 12 and the illuminances of the plurality of light fluxes L1 to L5 based on the illuminance signals S1 to S5. a memory 23 for storing the luminance data S6, based on the illuminance data S6 which is stored in the memory 23, as the illuminance of the light beam L 1 ~L 5 becomes a predetermined value, any light beam components in the light beam L 1 ~L 5 And a control unit 22 for controlling the shutter 12 so as to regulate the light fluxes L 6 to L 8 emitted by the ultrahigh-pressure mercury lamp 10 emitting light by the aperture ratio.
[0008]
In the exposure apparatus according to the second aspect, the light guide 14 is configured by bundling a plurality of optical fibers.
In the exposure apparatus according to claim 3, shutter 12 controls the opening ratio of the opening for passing the light beam L ₆ ~L _8, to regulate the luminous flux L ₆ ~L _8.
In the exposure apparatus according to the fourth aspect, the portions 4A, 4C, and 4E of the plurality of projection optical systems 4A to 4E have their optical axes arranged in a line along the Y direction, and the plurality of projection optical systems 4A to 4E. The other parts 4B and 4D of 4E have their optical axes parallel to the parts 4A, 4C and 4E of the plurality of projection optical systems and arranged in a line at a predetermined interval, and are substantially orthogonal to the Y direction. The mask 3 and the photosensitive substrate 5 are synchronously scanned in the in-plane direction of the photosensitive substrate 5.
[0009]
In the exposure apparatus according to claim 5, by connexion divided into the light guide 14 after the first and second light fluxes emitted respectively from the ultra-high pressure mercury lamp 10 L ₆ and L ₇ and by connexion condensing the light guide 14 Yotsute the light beam L ₁ and L ₂ the first and second obtained by the first and second illumination areas M1 and M2 differ from each other on the mask 5 in which a pattern is formed by illuminating each first and In the exposure method in which the respective images of the second illumination areas M1 and M2 are projected onto the photosensitive substrate 5 via the first and second projection optical systems 4A and 4B, respectively, the light is emitted from the first ultra-high pressure mercury lamp 10. for each opening ratio for the light flux L ₆ of the first shutter 12 to regulate the light beam L _6, which is by an aperture, a first processing for detecting the first and second illumination intensity of the light beam L ₁ and L _2, the 2 from the ultra-high pressure mercury lamp 10 And for each opening with respect to light flux L _7, second process of detecting the first and second illumination intensity of the light beam L ₁ and L ₂ of the second shutter 12 to the light beam L ₇ is regulated by the aperture rate, the first and on the basis of the illuminance signals S1 and S2 according to the second process, the illumination in association with each of the opening ratio of the first and second shutters 12, and first and second light beams L ₁ and L ₂ illuminance a third process of storing as data S6, when projecting the pattern onto the photosensitive substrate 5, so as to equalize the first and second illumination intensity of the light beam L ₁ and L _2, the illuminance data of the third process A fourth process for controlling the first and second shutters 12 based on S6 is provided.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below in detail with reference to the drawings.
[0011]
FIG. 1 shows a scanning exposure apparatus 1 as a whole, which exposes a large area pattern by only one-dimensional scanning. The scanning exposure apparatus 1 emits _five light beams L _{1 to} L ₅ with uniform illuminance from the illumination optical system 2, and different small illumination regions M _{1 to} M ₁ on the mask 3 by the light beams L _{1 to} L _5. Illuminate M5. The scanning exposure apparatus 1 projects a plurality of luminous fluxes transmitted through the mask 3 onto a photosensitive substrate 5 for manufacturing a liquid crystal display device via different projection optical systems 4A to 4E, respectively. The pattern images of the illumination areas M1 to M5 are formed on P1 to P5.
[0012]
Incidentally, the projection areas P1 to P5 on the photosensitive substrate 5 are such that adjacent projection areas (for example, P1 and P2, P2 and P3) are separated from each other by a predetermined distance in the X direction, and ends of the adjacent projection areas are adjacent to each other. Are arranged so as to overlap in the Y direction orthogonal to the X direction. For this reason, the projection optical systems 4A to 4E are also spaced apart from each other by a predetermined distance in the X direction corresponding to the arrangement of the projection areas P1 to P5, and are also overlapped in the Y direction.
[0013]
Each of the projection optical systems 4A to 4E is an equal-size erect system, and has the same arrangement as the illumination areas M1 to M5 on the mask 3. Therefore, the arrangement of the projection areas P1 to P5 on which the pattern images of the illumination areas M1 to M5 are formed is the same as that of the illumination areas M1 to M5. The plane arrangement of the optical axes of the light beams L _{1 to} L ₅ of the illumination optical system 2 is arranged in the same manner as the illumination areas M _{1 to} M ₅ on the mask 3.
[0014]
The mask 3 and the photosensitive substrate 5 are integrally held on a stage holder 6 in a state where they face each other. As a result, the mask 3 and the photosensitive substrate 5 are mechanically coupled so that their mutual positions are constant. The stage holding base 6 is provided with a driving device that drives with a long stroke in the scanning direction (X direction).
At the time of scanning, the scanning type exposure apparatus 1 drives the stage holder 6 in the X direction by this driving device, and makes the mask 3 and the photosensitive substrate 5 primary to the illumination optical system 2 and the projection optical systems 4A to 4E. Scan synchronously to the original. By this synchronous scanning, the image of the entire surface of the pattern area 3A of the mask 3 can be transferred to the photosensitive surface 5A of the photosensitive substrate 5.
[0015]
The mask 3 is supported by a mask stage 7 arranged on a stage holder 6, and is positioned at an arbitrary position in the in-plane direction of the mask 3 by a plurality of fine movement actuators (not shown). Thus, the scanning type exposure apparatus 1 can perform positioning by the fine movement actuator and correct the positional deviation of the pattern image caused by the inclination of the stage holding table 6 with respect to the projection optical systems 4A to 4E.
[0016]
As shown in FIG. 2, the illumination optical system 2 is provided with, for example, three ultra-high pressure mercury lamps 10, and luminous fluxes L _{6 to} L ₈ respectively emitted from the ultra-high pressure mercury lamp 10 are used as elliptical mirrors 11. Through a shutter 12 and a lens system 13, the light enters a light guide 14 formed by bundling a plurality of optical fibers and is focused.
The illumination optical system 2 divides the condensed light fluxes L _{6 to} L ₈ into five light fluxes L _{1 to} L ₅ by a light guide 14, and divides each of the obtained light fluxes L _{1 to} L ₅ into an emission unit. The illumination is made uniform by a fly-eye lens (not shown).
Incidentally, the shutter 12 is also used in the configuration of a normal illumination optical system, and does not increase the number of components.
[0017]
Subsequently, the illumination optical system 2, for example, a half mirror 15 the light beam L _1, irradiated to the field stop 17 through a condenser lens 16, the O connexion beam L ₁ to the field stop 17 shapes each into a desired shape. The illumination optical system 2, the light beam L ₁ that is shaped by irradiating on the pattern surface of the mask 3 through the relay lens 18 and 19 to form an image of the field stop 17.
[0018]
In the illumination optical system 2, a half mirror 15 is provided between the exit end of the light guide 14 and the condenser lens 16, and a part of the light beam L ₁ enters the light detection element 21. The illumination optical system 2, the light beam L ₂ ~L ₅ be treated in the same manner as the light beam L ₁ is irradiated on the pattern surface of the mask 3, a portion of each of the light beams L ₂ ~L ₅ to the light detection element 21 Incident.
[0019]
The illumination optical system 2 causes the photodetector 21 to generate illuminance signals S1 to S5 in accordance with the illuminance of each of a part of the light beam provided to the photodetector 21 via the half mirror 15 and the lens system 20. The signals S1 to S5 are given to the control unit 22. The illumination optical system 2 determines the illuminance of each of the light fluxes L _{1 to} L ₅ by the control unit 22 based on the illuminance signals S _{1 to S 5} , and stores the illuminance data S 6 generated in association with the aperture ratio of the respective shutters 12. 23.
[0020]
The illumination optical system 2 reads out the illuminance data S6 stored in the memory 23 to the control unit 22, and gives control signals S7 to S9 generated by the control unit 22 based on the illuminance data S6 to the shutter control units 24 to 26, respectively.
Thus, when the illuminance exceeds a proper value, the illumination optical system 2, by adjusting the respective aperture ratio of Yotsute three shutter 12 to the control unit 22, reducing the illuminance of the light beam L ₁ ~L ₅ to the proper value together we are, making uniform the illuminance of mutual light beam L ₂ ~L _5.
[0021]
Here, when obtaining the illuminance data S6, the illumination optical system 2 operates, for example, according to the illuminance data acquisition procedure shown in FIG. That is, the illumination optical system 2 enters from step SP0, clears the parameter M in step SP1, and proceeds to step SP2. In step SP2, the illumination optical system 2 fully opens the N (here, 3) light sources, that is, all the shutters 12 of the ultrahigh-pressure mercury lamp 10, sets the aperture ratio to 100%, and proceeds to step SP3.
[0022]
In step SP3, the illumination optical system 2 detects the illuminance of the light beam _L 1 ~L ₅ in this setting, proceeds to step SP4, the light beam _L 1 ~L each of the three shutter 12 the illumination of ₅ at this time It is stored in association with the aperture ratio. Subsequently, the illumination optical system 2 proceeds to step SP5, increments the parameter M to M + 1, and proceeds to step SP6. In step SP6, the illumination optical system 2 closes the shutter 12 of the M-th (here, the first) ultrahigh-pressure mercury lamp 10, sets the aperture ratio to 0%, and proceeds to step SP7.
[0023]
In step SP7, the illumination optical system 2 detects the illuminance of the light beam _L 1 ~L _5, the correspondence with the aperture ratio of the light beam _L 1 ~L 3 single shutter 12 each illuminance ₅ when this moves to step SP8 To remember. Subsequently, the illumination optical system 2 proceeds to step SP9, and determines whether or not the parameter M satisfies M = N.
If a negative result is obtained in step SP9, the illumination optical system 2 determines that the illuminance corresponding to the aperture ratios of the shutters 12 of all the ultrahigh-pressure mercury lamps 10 has not been detected, and proceeds to step SP10. In step SP10, the illumination optical system 2 sets the aperture ratio of the shutter 12 of the M-th (here, the first) ultrahigh-pressure mercury lamp 10 to 100% again, returns to step SP5, and repeats the above procedure.
[0024]
Eventually, when a positive result is obtained in step SP9, the illumination optical system 2 determines that the illuminance corresponding to the aperture ratios of the shutters 12 of all the ultra-high pressure mercury lamps 10 has been detected, and proceeds to step SP11 to acquire illuminance data. End the procedure.
Yotsute to total such as illuminance of the light beam L ₁ ~L ₅ when the opening ratio of 100% thus obtained, a difference between the illuminance of the light beam L ₁ ~L ₅ when the opening ratio of 0%, lighting The optical system 2 can detect the illuminance of each of the light beams L _{6 to} L ₈ emitted from the ultrahigh-pressure mercury lamp 10 corresponding to the shutter 12 whose aperture ratio is controlled.
[0025]
Further, when each of the illuminance of the light beam _L 6 ~L ₈ is seen, the illumination optical system 2, the light beam L to the optical beam _L 1 ~L ₅ is a secondary light beam which is obtained by dividing the light beam _L 6 ~L ₈ each division ratio of ₆ ~L ₈ can be detected based on the difference described above. It is clear that this division ratio is constant unless the configuration of the light guide 14 is changed.
[0026]
In the above configuration, the illumination optical system 2 obtains the illuminance data S6 corresponding to each of the three ultra-high-pressure mercury lamps 10 and exposes them to the memory 23, for example, before exposing the one-lot photosensitive substrate 5 or immediately after the lamp replacement. Keep it.
The illumination optical system 2, when obtaining the illuminance data S6, when any one of the illuminance of the light beam L ₁ ~L ₅ detects that exceeds a predetermined value, the luminance of any of the ultra-high pressure mercury lamp 10 is excessively large It is determined that there is, and the illuminance of the light fluxes L _{1 to} L ₅ is calibrated.
[0027]
That is, the illumination optical system 2 reads the illuminance data S6 acquired immediately before exposure from the memory 23, the illuminance of the light beam L ₆ ~L ₈ three ultra-high pressure mercury lamp 10 is emitted, the aperture ratio of the three shutters 12 , based on the respective division of the light beam _L 6 ~L ₈ to the light beam _L 1 ~L _5, sets the optimum combination of aperture ratio for the three shutter 12.
[0028]
Accordingly, even if the brightness of any of the ultrahigh-pressure mercury lamps 10 is excessive and it is difficult to adjust the exposure amount to an appropriate value only by adjusting the scanning speed, the entire surface of the photosensitive substrate 5 can be controlled. The photosensitive substrate 5 can be exposed at an appropriate exposure amount by illuminating with a light flux having a uniform illuminance.
[0029]
According to the above configuration, the aperture ratio of the shutter 12 that regulates the light fluxes L _{6 to} L ₈ emitted from the plurality of ultrahigh-pressure mercury lamps 10 and the light fluxes L _{6 to} L ₈ are collected by the light guide 14. based in association with the illuminance of the light beam L ₁ ~L ₅ obtained by light and dividing the illuminance data S6 which is stored in the memory 23, sets the optimum combination of aperture ratio three shutter 12 before exposure be Accordingly, even if the intensity of the ultrahigh-pressure mercury lamp 10 is too large to adjust the exposure amount to an appropriate value only by controlling the scanning speed of the photosensitive substrate with respect to the illumination optical system 2, an appropriate exposure amount is given to the photosensitive substrate 5. be able to.
[0030]
In the above-described embodiment, the case of exposing the photosensitive substrate 5 for manufacturing a liquid crystal display device has been described. However, the present invention is not limited to this, and any photosensitive substrate, for example, a photosensitive substrate for manufacturing a semiconductor element, may be used. The present invention can be applied to a case where a substrate is exposed.
[0031]
Further, in the above-described embodiment, the case where the present invention is applied to the scanning exposure apparatus having the five projection optical systems 4A to 4E has been described. However, the present invention is not limited to this, and the invention is not limited to the five projection optical systems. The present invention can also be applied to an exposure apparatus in which an arbitrary number is arranged.
[0032]
Further, in the above-described embodiment, a case has been described in which the present invention is applied to the exposure apparatus 1 for scanning and exposing only in one dimension, but the present invention is not limited to this, and the exposure apparatus for scanning and exposing in two dimensions Also applicable to
[0033]
Further, in the aforementioned embodiments have dealt with the case of calibrating the illuminance of the light beam L ₁ ~L ₅ is a secondary light beam before the exposure, the present invention is not limited thereto, to regulate the primary light beam during exposure Thus, the present invention can be applied to the case where the illuminance of the secondary light beam is controlled.
[0034]
Furthermore, in the above-described embodiment, the case where the aperture ratio of the shutter 12 is controlled to regulate the light fluxes L _{6 to} L ₈ has been described. However, the present invention is not limited to this, and the light flux regulating means for regulating the light flux is optional. The configuration of
[0035]
Further, in the above-described embodiment, the case where the light beam is condensed and divided by the light guide 14 has been described. However, the present invention is not limited to this, and the light beam is condensed and divided by an optical system having an arbitrary configuration. It can also be applied to
[0036]
【The invention's effect】
As described above, according to the present invention, the regulation state of the beam regulation means for regulating the respective primary beams emitted from the plurality of light sources, and the primary beam is condensed and divided by the optical transmission path. The scanning speed of the photosensitive substrate with respect to the illumination optical system is set by setting the optimum combination of the restricting states for the plurality of light beam restricting means based on the storage result stored in the storing means in association with the obtained illuminance of the secondary light flux. It is possible to realize an exposure apparatus and an exposure method that can provide an appropriate exposure amount to a photosensitive substrate even if the brightness of the light source is so large that the exposure amount cannot be adjusted to an appropriate value only by the above control.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a scanning type exposure apparatus according to an embodiment of an exposure apparatus and an exposure method according to the present invention.
FIG. 2 is a schematic diagram illustrating the configuration of an illumination optical system according to an embodiment.
FIG. 3 is a flowchart for explaining an illuminance data acquisition procedure according to an embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Scanning exposure apparatus, 2 ... Illumination optical system, 3 ... Mask, 3A ... Pattern area, 4A-4E ... Projection optical system, 5 ... Photosensitive substrate, 5A ... Photosensitive surface, 6 ... Stage holder 7, mask stage 10, ultra-high pressure mercury lamp 11, elliptical mirror 12, shutter 13, lens system 14, light guide 15, half mirror 16, Condenser lens, 17 Field stop, 18, 19 Relay lens, 20 Lens system, 21 Photodetector element, 22 Control unit, 23 Memory, 24-26 Shutter control unit, L ₁ ~L ₈ ...... beam, P1~P5 ...... projection area, M1~M5 ...... illumination area.

Claims (5)

A pattern is formed by a plurality of secondary luminous fluxes obtained by condensing a plurality of primary luminous fluxes respectively emitted from a plurality of light sources by an optical transmission path and then dividing by the optical transmission path. An illumination optical system for illuminating a plurality of mutually different regions on the mask, and a plurality of projection optical systems arranged corresponding to the plurality of regions, wherein each image of the plurality of regions is In an exposure apparatus that projects onto a photosensitive substrate via each of the projection optical systems,
A plurality of light beam regulating means for regulating each of the primary light beams emitted by the plurality of light sources;
Illuminance detection means for detecting the illuminance of the secondary light beam;
Based on the detection result, a storage unit that stores each of the regulation states by the plurality of light beam regulation units and the illuminance of the plurality of secondary light beams in association with each other,
Based on the storage result stored in the storage means, the primary light source emitting an arbitrary light beam component in the secondary light beam is emitted such that the illuminance of the secondary light beam becomes a predetermined value. An exposure apparatus comprising: a control unit that controls the light beam regulating unit so as to regulate the light beam . The exposure apparatus according to claim 1, wherein the optical transmission path is configured by bundling a plurality of optical fibers. 2. The exposure apparatus according to claim 1, wherein the light flux regulating unit regulates the primary light flux by controlling an aperture ratio of an opening through which the primary light flux passes. 3. Some of the plurality of projection optical systems have their optical axes arranged in a line along a first direction,
Another part of the plurality of projection optical systems, the optical axis is parallel to a part of the plurality of projection optical systems, and are arranged in a row at a predetermined interval,
2. The exposure apparatus according to claim 1, wherein the mask and the photosensitive substrate are synchronously scanned in a direction substantially perpendicular to the first direction and in an in-plane direction of the photosensitive substrate. First light beams emitted from the first and second light sources, respectively, are condensed by an optical transmission line and then divided by the optical transmission line to obtain first and second secondary light beams. Illuminating different first and second areas on the mask on which the pattern is formed, respectively, and exposing the respective images of the first and second areas via the first and second projection optical systems, respectively. In an exposure method for projecting onto a substrate,
A first detecting unit that detects the illuminance of the first and second secondary light beams for each state of the primary light beam regulated by the first light beam regulating unit that regulates the primary light beam emitted from the first light source; Processing and
A second detecting means for detecting the illuminance of the first and second secondary light fluxes for each of the regulation states of the primary light flux by the second light flux regulating means for regulating the primary light flux emitted from the second light source; Processing and
Based on the detection results obtained by the first and second processes, the respective restriction states by the first and second light beam restriction means are associated with the illuminance of the first and second secondary light beams. A third process for storing;
When projecting the pattern onto the photosensitive substrate, the first and second secondary light beams are made uniform based on the storage result of the third processing so as to make the illuminance of the first and second secondary light beams uniform. A fourth process for controlling the light beam regulating means.

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