JP2004240097A - Exposure method and aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure method capable of easily setting light quantity. <P>SOLUTION: In the exposure method for setting light quantity and exposing a mask pattern on a substrate 100 by getting a shutter blade in and out of an optical path, the sector 14 is operated in such a manner that the speed of the sector 14 when edges 14a, 14b of the sector 14 go out from the inside of the optical path to the outside thereof attains to the maximum speed v1 when getting the sector 14 in and out. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exposure method and an exposure device.
[0002]
[Prior art]
There is known a method of setting a light amount by opening and closing a shutter and exposing a mask pattern on a substrate.
[0003]
[Problems to be solved by the invention]
Conventionally, the effects of acceleration and deceleration of the shutter blades that occur when the shutter is opened and closed have not been considered. However, if the shutter is opened and closed during acceleration and deceleration of the shutter blades, various inconveniences arise in setting the light amount. For example, the integrated exposure must be considered as a function of shutter blade speed. Further, in order to perform exposure with a uniform exposure amount over the exposure area, it is necessary to consider a change in light amount when the shutter is opened and closed. However, if the influence of the acceleration of the shutter blades is also taken into consideration, the calculation of the light amount becomes complicated. For this reason, it has been difficult to accurately obtain an integrated exposure amount set in advance according to the sensitivity of the resist, and to perform exposure with a uniform exposure amount over an exposure region.
[0004]
Therefore, an object of the present invention is to provide an exposure method and an exposure apparatus capable of easily setting a light amount.
[0005]
[Means for Solving the Problems]
Hereinafter, the present invention will be described. In addition, in order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are added in parentheses, but the present invention is not limited to the illustrated embodiment.
[0006]
An exposure method according to the present invention is directed to an exposure method for exposing a mask pattern on a substrate by setting a light amount by moving a shutter blade (14) in and out of an optical path of a light beam (L) capable of contributing to exposure of the substrate (100). The speed of the shutter blade when the edge (14a, 14b) of the shutter blade exits from the optical path to the outside of the optical path reaches the maximum speed (v1) when the shutter blade is moved in and out. The above-described problem is solved by operating the shutter blade.
[0007]
According to the exposure method of the present invention, the speed at which the edge finishes traversing the luminous flux when the shutter is opened or closed is the maximum speed when the shutter blade is moved in and out. For this reason, the speed of the shutter blades during the period from when the shutter starts to open until the shutter is fully opened and between the time when the shutter starts to close and when the shutter is fully closed are higher than in the past. Therefore, the time when the edge crosses the light beam is reduced, and various inconveniences caused by the edge of the shutter blade crossing the light beam during acceleration and deceleration of the shutter blade are eliminated. For example, the variation in the amount of light with respect to the exposure area, which occurs when the edge crosses the light beam, is reduced. In addition, since the time when the edge crosses the light beam is shorter than the time when the shutter is fully open, the influence of the amount of light while the edge crosses the light beam on the integrated exposure is reduced, and the sensitivity of the resist is reduced. It becomes easy to obtain a corresponding integrated exposure amount.
[0008]
In the exposure method of the present invention, acceleration / deceleration that occurs when the shutter blade is operated at the maximum speed ends while the edge is outside the optical path, and the edge is reduced while operating at the maximum speed. The shutter blade may be operated to cross the optical path. In this case, the edge of the shutter blade crosses the light beam only while the shutter blade is moving at the maximum speed. For this reason, various inconveniences caused by the edge of the shutter blade traversing the light beam during acceleration and deceleration of the shutter blade are eliminated. For example, the amount of light passing through the shutter needs to be considered as a function of the speed of the shutter blades, but since the speed of the shutter blades is constant, it is easy to calculate the amount of light when opening and closing the shutter. Therefore, it becomes easy to perform exposure with an integrated exposure amount according to the sensitivity of the resist. Also, it is easy to set a uniform light amount over the exposure area.
[0009]
In the exposure method of the present invention, the direction in which the edge crosses the optical path may be the same direction when the shutter blade is protruded from the optical path and when the shutter blade is inserted into the optical path. In this case, since the light quantity distribution when the shutter blades are put out of the optical path and the light quantity distribution when the shutter blades are put into the optical path are mutually inverted distributions, a uniform light quantity is set over the exposure area.
[0010]
In the exposure method of the present invention, the shutter blade may be operated at the maximum speed until the shutter blade comes out of the optical path and enters the optical path. In this case, since the speed of the shutter blades is constant while the shutter is open, it is easy to calculate the time during which the shutter is open.
[0011]
In the exposure method of the present invention, the speed of the shutter blade is temporarily reduced and then accelerated again to the maximum speed before the shutter blade is taken out of the optical path and put into the optical path, and the timing of ending the acceleration The shutter blades may be operated such that the time when the edge starts traversing the optical path coincides with the time. In this case, the time for opening the optical path is adjusted by the acceleration and deceleration of the shutter blade. The time to open the optical path is determined by the integrated light amount required for exposure and the illuminance of the light source, and when the time when the optical path is opened is specified, the time when the optical path should be closed is also specified, and further, the edge starts to cross the optical path. The time when it should be specified is also specified. In the above-described embodiment, since the acceleration ends when the edge starts to cross, only the time required for the acceleration is started before the time when the edge should start to cross the optical path, and only the time required for the exposure is accurately obtained. The light path can be opened. Note that the concept of reducing the speed of the shutter blade includes stopping and moving the shutter blade in the opposite direction. If the position at which acceleration is restarted is adjusted by stopping and moving the shutter blades in the opposite direction, it is easier to adjust the speed at which the edge crosses the light beam and the time at which exposure ends.
[0012]
In the exposure method of the present invention, the operation of taking out the shutter blade from the optical path may be started before the end of the alignment between the substrate and the photomask. In this case, as compared with the case where the driving of the shutter blade is started after the completion of the alignment, the time from the completion of the alignment until the speed of the shutter blade reaches the set speed is reduced.
[0013]
In the exposure method of the present invention, the shutter blades may be arranged so that an edge crossing the optical path when the shutter blade is taken out of the optical path starts crossing the optical path after the alignment between the substrate and the photomask is completed. May be operated. That is, when the operation of taking the shutter blades out of the optical path is started before the end of the alignment as described above, conditions may be set so that exposure failure does not occur.
[0014]
An exposure apparatus (1) according to the present invention includes a shutter blade (14) that can enter and exit an optical path of a light beam that can contribute to exposure of a substrate (100), and a driving unit (15) that drives the shutter blade. In an exposure apparatus that exposes a mask pattern to a substrate, the driving unit is configured such that the speed of the shutter blade when the edge of the shutter blade goes out of the optical path to the outside of the optical path is the maximum speed when the shutter blade is moved in and out. By driving the shutter blades as described above, the above-mentioned problem is solved.
[0015]
According to the exposure apparatus of the present invention, the above-described exposure method of the present invention can be realized.
[0016]
In the exposure apparatus of the present invention, the driving unit may swing the shutter blade while the light beam is blocked by the shutter blade. In this case, the position where the light beam is irradiated changes with the swing of the shutter blade. Therefore, the same portion of the shutter blade is prevented from being heated for a long time, and the deformation and breakage of the shutter blade are prevented.
[0017]
In the exposure apparatus of the present invention, the surface of the shutter blade on the light-emitting side of the light beam may be a black body. In this case, heat radiation from the shutter blades is facilitated, and deformation and breakage of the shutter blades are prevented.
[0018]
In the exposure apparatus of the present invention, the shutter blade may have an uneven portion on a surface on an emission side of the light beam. In this case, since the surface area of the shutter blade is increased, heat is easily released, and deformation and breakage of the shutter blade are prevented.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a side view showing a configuration of an exposure apparatus 1 of the present invention. The exposure apparatus 1 is configured as an apparatus that performs proximity type exposure on the substrate 100. The substrate 100 is configured as a glass substrate such as a color filter or a TFT substrate.
[0020]
The exposure apparatus 1 includes a light source 2, an elliptical mirror 3 for condensing light from the light source 2, a mirror 4 for changing a direction of a light beam L from the light source 2 and the elliptical mirror 3, and a light beam L from the mirror 4. A rotary shutter 6 (hereinafter simply referred to as “shutter 6”) for opening and closing the optical path, an integrator lens 5 for equalizing the light flux L passing through the shutter 6, and a direction of the light flux L from the integrator lens 5 are changed. A parabolic mirror 7 for changing the light beam L into a parallel light beam, a photomask 9 to which the light beam L from the parabolic mirror 7 is irradiated, a stage 10 on which a substrate 100 to be exposed is mounted, and a photomask 4 A driving device 11 for driving the stage 2 in the horizontal and vertical directions, and a control device 13 for controlling various devices such as the driving device 11.
[0021]
The shutter 6 includes a shutter blade 14 that can be moved in and out of an optical path, a servomotor 15 (hereinafter, simply referred to as a “motor 15”) that drives the shutter blade 14, a rotary encoder 16 that detects a rotational position of the motor 15, and a control unit. A motor driver 17 that supplies electric power to the motor 15 based on an instruction signal from the device 13.
[0022]
The shutter blade 14 is formed in a semicircular shape centered on the output shaft 15a of the motor 15 as shown in FIG. 2A, and the radius thereof is set to be larger than the cross-sectional diameter of the light beam L. . The shutter blades 14 are formed of a high heat transfer material such as copper or aluminum. For example, aluminum is vapor-deposited on the surface on the incident side (the integrator lens 5 side) of the shutter blade 14, and the reflectance is set high. The back surface (the surface on the emission side of the light beam L) is, for example, a black body or provided with irregularities so as to have a large surface area, thereby facilitating heat radiation. In order to form a black body, for example, the back surface of the shutter blade 14 may be painted with a black paint. The unevenness may be provided by, for example, pressing the shutter blades 14.
[0023]
The shutter blade 14 is rotated in the direction of arrow y1 by the motor 15, and a position where the edge 14a coincides with the position P0 is set as a stop position. Further, as shown in FIG. 2B, θ1 is the rotation amount during the acceleration of the shutter blade 14 (time T1), and θ2 is the rotation amount during the rotation of the shutter blade 14 at the maximum speed (constant speed) v1 (time The rotation amount of T2), θ3, is set as the rotation amount during the time when the shutter blades 14 decelerate (time T3). The position P1 is a position where the edge 14a starts to cross the light beam L, and the position P2 is a position of the edge 14a when the edge 14b goes out of the light path to the outside of the light path and finishes crossing the light beam L. The position P0 is set at a position shifted from the position P1 by θ1 in a direction opposite to the rotation direction of the shutter blade 14. θ1 is set by, for example, obtaining the amount of rotation required for the shutter blade 14 to reach the speed v1 by an experiment or the like. The speed v1 is set to, for example, 5 m / sec or more at the position of the center of the light beam L. Note that the edge 14a exits from the inside of the optical path to the outside of the optical path at the position P3, and finishes crossing the light flux L.
[0024]
The detection signal of the rotary encoder 16 is output to the control device 13. The control device 13 rotates the motor 15 at a predetermined angular speed via the motor driver 17 based on a signal from the rotary encoder 16 and positions the output shaft 15a of the motor 15 at a predetermined position.
[0025]
The operation of the exposure apparatus 1 having the above configuration will be described. FIG. 3 is a flowchart illustrating a procedure of the alignment process performed by the control device 13. This processing is started, for example, when the substrate 100 is transferred to the stage 10. In step S1, the control device 13 outputs an instruction signal to the driving device 12, drives the stage 10 in the horizontal direction so that the substrate 100 is positioned below the photomask 9, and at the same time through a predetermined proximity gap. The stage 10 is driven upward so that the photomask 9 and the substrate 100 face each other. In step S2, the driving device 11 and the driving device 11 are adjusted to align the alignment mark (not shown) of the photomask 9 with the alignment mark (not shown) of the substrate 100 based on an image signal captured by a camera (not shown). An instruction signal is output to the driving device 12.
[0026]
FIG. 4 is a flowchart illustrating a procedure of a drive instruction process executed by the control device 13. This processing is started, for example, when the substrate 100 is transferred to the stage 10. When this process is started, the shutter blade 14 is stopped at a position where the edge 14a coincides with the position P0, and the light beam L is blocked by the shutter 6.
[0027]
First, the control device 13 determines whether or not step S1 in FIG. 3 has ended, and waits until step S1 ends (step S11). When it is determined that step S1 has been completed, a waiting time T0 until the motor 15 is driven is set in the timer, and the timer starts counting (step S12).
[0028]
The time T0 satisfies the following equation, for example, assuming that the time from when it is determined that the step S1 is completed (time t0 in FIG. 2B) to when the alignment of the alignment mark is completed in step S2 is Te. Set as follows.
(Equation 1)
max Te = T0 + T1
Here, max Te is the maximum value that Te can take. The max Te is obtained by, for example, an experiment.
[0029]
In step S13, it is determined whether or not the time T0 has elapsed, and the process waits until it is determined that the time T0 has elapsed. If it is determined that the time T0 has elapsed, the driving of the motor 15 is started via the motor driver 17 so as to rotate the motor 15 at a constant speed (step S14).
[0030]
By the processing in FIG. 4, as shown in FIG. 2B, driving of the shutter blades 14 is started at time t1. By setting the time T0 as in Equation 1, the driving of the shutter blades 14 is started before the time te when the alignment ends, and the exposure is started after the time te. The edges 14a and 14b cross the light beam L while the shutter blade 14 rotates at the maximum speed v1 (time T2).
[0031]
Note that the time T0 may be appropriately calculated by the control device 13 by predicting or learning the time Te, or a predetermined time T0 may be stored in the control device 13. . When the time Te is shorter than the time T1, the time T0 may be set to 0, and the driving instruction may be issued immediately at the time t0.
[0032]
When considering the position where the edges 14a and 14b cross the light beam, the light beam effective for exposure among the light beams from the light source 2 may be considered. For example, when the speed at which the edges 14a and 14b cross the light beam is set to a constant speed, the light beam is irradiated to the outside of the integrator lens 5 and does not reach the substrate 100, or passes through an aperture (not shown) provided in the light path. For light beams and the like that do not occur, the edges 14a and 14b may cross these light beams when the shutter blade 14 is accelerated or decelerated.
[0033]
When the shutter 6 is closed for a long time, such as while the substrate 100 is being conveyed to the stage 2, the shutter blades 14 are swung within a range in which the light flux L does not pass (a range in which the edge 14a is within θ1 and θ3). May be moved to prevent the same portion of the shutter blade from being heated for an extended period of time. Alternatively, air may be blown onto the heated portion to cool it.
[0034]
The present invention is not limited to the above embodiments, and may be implemented in various forms as long as the technical idea of the present invention is substantially the same.
[0035]
When the shutter 6 is fully opened (between the time when the edge 14a crosses the light beam L and the time when the edge 14b starts to cross the light beam L), the shutter blade 14 may be decelerated and accelerated. One example is shown in FIGS. In this figure, the shutter blades 14 are set to decelerate when the edge 14a is in the range of θ5, stop when the edge 14a is in the position P4, and accelerate when the edge 14a is in the range of θ6. The position P4 is set, for example, at a position shifted by θ6 from a position P5 at which the edge 14b starts to cross the light beam L. θ6 is, for example, the amount of rotation required for the shutter blade 14 to reach the maximum speed v1. Since the exposure time T2 is determined by the integrated light amount required for the exposure and the illuminance of the light source 2, when set as shown in FIG. 5, the time tr at which the driving of the shutter blades 14 is started again at the position P4 is appropriately set. By setting, the exposure can be performed exactly during the exposure time T2. For example, when it is difficult to reduce the speed from the speed v1 to the speed 0 in the range of θ5, the shutter blade 14 is moved in the reverse direction after passing the position P4, and the shutter blade 14 is stopped at the position P4. You may let it.
[0036]
In the example described above, the acceleration ends when the edge 14a reaches the position P1, and the deceleration starts when the edge 14a reaches the position P2. However, the acceleration ends before the edge 14a reaches the position P1. Alternatively, deceleration may be started after the edge 14a has passed the position P2. The maximum speed v1 may be reached when the edges 14a and 14b finish traversing the light beam L, such as when the edge 14a reaches the position P3.
[0037]
The maximum speed v1 may be appropriately set according to various circumstances such as the performance of the motor 15 and the exposure time. It is desirable that the maximum speed v1 be as large as possible from the viewpoint of shortening the time for the edges 14a and 14b to cross the light beam L. On the other hand, the range that can be secured as the acceleration range of the shutter blade 14 is from the time when one edge has finished traversing the light beam L to the time when the other edge has finished traversing the light beam L. For example, in the case of a semicircular shutter blade like the shutter blade 14, a range in which the shutter blade 14 makes a half circle is a range that can be used for acceleration. Therefore, for example, when the acceleration performance of the motor 15 is high and the motor 15 can be accelerated to the maximum angular speed of the motor 15 while the shutter blade 14 is half-turned, the speed of the shutter blade 14 at that time is set as the maximum speed v1. May be. Further, for example, when the motor 15 cannot be accelerated to the maximum angular velocity of the motor 15 while the shutter blade 14 is half-turned, an appropriate speed is set as the maximum speed v1 according to the size of the range available for acceleration. You may.
[0038]
The shutter 6 may be provided at any position in the optical path. For example, it may be provided on the parabolic mirror 7 side of the integrator lens 5. The shutter 6 is not limited to a rotary shutter. Any known shutter can be used as the shutter of the exposure apparatus of the present invention as long as the light beam can be blocked when the shutter blades are accelerated or decelerated. For example, a reciprocating shutter blade may be used.
[0039]
【The invention's effect】
As described above, according to the present invention, the speed of the shutter when the edge finishes traversing the light beam is the maximum speed when the shutter blade is moved in and out. That is, the speed at which the edge crosses the light beam is higher than in the conventional case. For this reason, the time when the edge crosses the light beam is reduced, and various inconveniences caused by the edge of the shutter blade crossing the light beam during acceleration and deceleration of the shutter blade are eliminated. For example, the variation in the amount of light with respect to the exposure area, which occurs when the edge crosses the light beam, is reduced. In addition, since the time when the edge crosses the light beam is shorter than the time when the shutter is fully open, the influence of the amount of light while the edge crosses the light beam on the integrated exposure is reduced, and the sensitivity of the resist is reduced. It becomes easy to obtain a corresponding integrated exposure amount.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an exposure apparatus of the present invention.
FIG. 2 is a diagram showing a shape and a speed change of a shutter blade of the exposure apparatus of FIG.
FIG. 3 is a flowchart illustrating a procedure of a positioning process performed by a control device of the exposure apparatus of FIG. 1;
FIG. 4 is a flowchart illustrating a procedure of a drive instruction process executed by a control device of the exposure apparatus of FIG. 1;
FIG. 5 is a modified example of the change in the speed of the shutter blade in FIG. 2;
[Explanation of symbols]
REFERENCE SIGNS LIST 1 Exposure device 9 Photomask 11 Drive device 12 Drive device 13 Control device 14 Shutter blade 15 Motor 100 Substrate

Claims (11)

In an exposure method in which a shutter blade is put in and out of an optical path of a light beam that can contribute to exposure of a substrate to set a light amount, and a mask pattern is exposed on the substrate,
Operating the shutter blades such that the speed of the shutter blades when the edge of the shutter blades exits from the optical path to the outside of the optical path has reached the maximum speed when the shutter blades are moved in and out. Exposure method. The acceleration / deceleration that occurs when operating the shutter blade at the maximum speed ends while the edge is outside the optical path, and the edge crosses the optical path while operating at the maximum speed. The exposure method according to claim 1, wherein the shutter blade is operated. The exposure according to claim 2, wherein the direction in which the edge crosses the optical path is the same direction when the shutter blade is protruded from the optical path and when the shutter blade is inserted into the optical path. Method. The exposure method according to any one of claims 1 to 3, wherein the shutter blade is operated at the maximum speed until the shutter blade exits from the optical path and enters the optical path. The shutter blade is once reduced in speed and then accelerated again to the maximum speed until the shutter blade is moved out of the optical path and into the optical path, and the end time of the acceleration and the optical path of the edge are changed. The exposure method according to any one of claims 1 to 3, wherein the shutter blades are operated such that a timing of starting the crossing coincides. The exposure method according to any one of claims 1 to 5, wherein an operation of taking out the shutter blade from within the optical path is started before positioning of the substrate and the photomask is completed. Operating the shutter blades so that an edge crossing the optical path when the shutter blade is taken out of the optical path starts crossing the optical path after the alignment between the substrate and the photomask is completed. The exposure method according to claim 6. An exposure apparatus for exposing a mask pattern to a substrate, comprising: a shutter blade that can be moved in and out of an optical path of a light beam that can contribute to exposure of the substrate; and a driving unit that drives the shutter blade.
The driving unit controls the shutter blade so that the speed of the shutter blade when the edge of the shutter blade goes out of the optical path to the outside of the optical path has reached the maximum speed when the shutter blade is moved in and out. An exposure apparatus characterized by being driven. 9. The exposure apparatus according to claim 8, wherein the driving unit swings the shutter blade while the light beam is blocked by the shutter blade. The exposure apparatus according to claim 8, wherein a surface of the shutter blade on the light-emitting side of the light beam is a black body. The exposure apparatus according to any one of claims 8 to 10, wherein the shutter blade has an uneven portion on a surface on an emission side of the light beam.

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