JPH10284376A - Light source and aligner provided with the light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably control the output of a light source even during open/close operation of a shutter when illuminating light from a light source such as a mercury lamp is used by opening/closing the shutter. SOLUTION: Illuminating light from a mercury lamp 1 is collected by an oval mirror 2 to be split by a beam splitter 3, the illuminating light reflected by the beam splinter 3 is led to a reticle R through a shutter 5, an interference filter 7, etc., and the illuminating light split in the middle is received by an integrator sensor 16. The illuminating light transmitted through the beam splitter 3 is led to a mercury lamp output sensor 32, and the output of the mercury lamp 1 is controlled based on a signal obtained by correcting the detection signal of the mercury lamp output sensor 32 by the detection signal of the integrator sensor 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device having a function of controlling the output of a light source such as an ultra-high pressure mercury lamp, and a lithography for manufacturing a semiconductor device or a liquid crystal display device provided with the light source device. The present invention relates to an exposure apparatus used when a mask pattern is transferred onto a substrate in a process.

[0002]

2. Description of the Related Art When manufacturing a semiconductor device or the like, a pattern of a reticle as a mask is transferred onto a wafer (or a glass plate or the like) coated with a photoresist through a projection optical system under exposure light. A projection exposure apparatus such as a stepper and a proximity type exposure apparatus for directly transferring a reticle pattern onto a wafer are used. In these exposure apparatuses, the exposure light is conventionally g of an ultra-high pressure mercury lamp (hereinafter simply referred to as “mercury lamp”).
Line (wavelength 436 nm), h line (wavelength 405 nm), i line (wavelength 365 nm) and the like are widely used.

In a conventional exposure apparatus using a mercury lamp as an exposure light source, constant power control for turning on the mercury lamp at a constant power has been performed. Even when such constant power control is performed, the output of the mercury lamp tends to fluctuate, so that conventionally, exposure light from the mercury lamp is passed through a shutter in order to give a proper exposure amount to the photoresist on the wafer. In addition to opening and closing, after the shutter, the light quantity of the light beam branched from the optical path of the exposure light is measured by an integrator sensor including a photoelectric detector. Then, after opening the shutter, the amount of exposure light irradiated onto the wafer is indirectly integrated via an integrator sensor, and the integrated amount of light is measured in advance with respect to the target exposure amount before exposure. When the shutter is closed, the shutter is closed when the amount of light passing therethrough decreases.

[0004]

As described above, in the conventional exposure apparatus, the mercury lamp is driven at a constant power, and the shutter is opened and closed based on the detection result of the integrator sensor provided behind the shutter to reduce the exposure amount. Had control.
However, recently, mercury lamps that can obtain higher output by driving with higher power have been used due to the improvement of the performance of mercury lamps, and the sensitivity of photoresist as a photosensitive material has been gradually increased. Therefore, the ratio of the exposure amount during the shutter closing operation to the entire exposure amount is increasing.

In this case, during the closing operation of the shutter, there is no method for correcting the output fluctuation of the mercury lamp. Therefore, if the light amount fluctuation during the closing operation is large, the fluctuation amount of the exposure amount as a whole also becomes large. As a result, there is a disadvantage that an appropriate exposure amount cannot be obtained. If an appropriate amount of exposure is not obtained in this way, variations in the line width of the resist pattern for each shot area on the wafer due to variations in the amount of exposure, and eventually, malfunctions of semiconductor devices and the like finally manufactured will occur.

In order to suppress the fluctuation of the output of the mercury lamp during the closing operation of the shutter, recently, a sensor arranged in front of the shutter constantly measures the amount of illumination light from the mercury lamp. A control method for comparing the power with a predetermined reference value and adjusting the power to be applied to the mercury lamp according to the difference is also being studied. However, when a normal mercury lamp is used, the exposure light having a desired wavelength is selected by a wavelength selection member disposed after the shutter. There is an inconvenience that part of the light reflected by the shutter enters the sensor in front of the shutter. As described above, when the reflected light from the wavelength selection member enters the sensor, the output of the sensor fluctuates with the opening and closing of the shutter. Therefore, it is difficult to stably control the output of the mercury lamp while the shutter is driven. is there.

In view of the above, the present invention can stably control the output of a light source such as a mercury lamp even when the shutter is used to open and close the shutter. It is an object to provide a light source device. Still another object of the present invention is to provide an exposure apparatus provided with such a light source device.

[0008]

A first light source device according to the present invention comprises, as shown in FIGS. 1 and 2, a light source (1) for generating illumination light and an optical path of the illumination light from the light source. A shutter (5) that opens and closes, wherein the illumination light from the light source (1) is opened and closed by the shutter (5) for use by the illumination from the light source (1) without passing through the shutter (5). A first photoelectric detector (32) for receiving a part of light;
A light beam splitting member (14) for splitting a part of the illumination light passing through the shutter (5), a second photoelectric detector (16) for receiving the light beam split by the light beam splitting member, and a first photodetector thereof.
A control system (26) for controlling the output of the light source (1) according to the detection signals of the photoelectric detector and the second photoelectric detector.

In the present invention, when, for example, a wavelength selecting member is provided after the shutter (5), when the shutter (5) is opened, reflected light from the wavelength selecting member is directed to the light source (1). Returning, and further entering the first photoelectric detector (32), the detection signal of the first photoelectric detector (32) changes when the shutter (5) is opened and closed. At this time, the amount of light returning to the first photoelectric detector (32) is proportional to the amount of light passing through the shutter (5), that is, the detection signal of the second photoelectric detector (16). The relationship between the detection signal of the detector (16) and the change amount of the detection signal of the first photoelectric detector (32) may be obtained. And the first photoelectric detector (32)
The light source (1) is such that the signal obtained by correcting the detection signal of the second photoelectric detector (16) in accordance with the detection signal of the second photoelectric detector (16) becomes a predetermined level.
, The output of the light source can be controlled stably.

[0010] Further, a state in which the shutter (5) is opening,
Or, in the closed state, for example, part of the reflected light from the wavelength selection member is blocked by the shutter (5) and does not return to the first photoelectric detector (32) side. That is, since the amount of change in the detection signal of the first photoelectric detector (32) is not completely proportional to the detection signal of the second photoelectric detector (16) in a strict sense, the amount of change is determined in advance by the second photoelectric detector. The function is stored as a function of the detection signal of the detector (16), and the first photoelectric detector (3) is used in real time in actual operation using the function.
By correcting the detection signal of 2), the stability of the output of the light source (1) is improved.

At this time, the point is that it is only necessary to detect the amount of light passing through the shutter (5).
Instead of 4) and the second photoelectric detector (16), a sensor (rotary encoder or the like) capable of detecting the opening / closing degree of the shutter (5) (ratio of light flux that can pass) is used, and is detected via this sensor. The detection signal of the first photoelectric detector (32) may be corrected according to the opening / closing degree of the shutter.

A second light source device according to the present invention comprises, as shown in FIGS. 4 and 2, a light source (1) for generating illumination light, and a shutter () for opening and closing the optical path of the illumination light from the light source. And 5) the illumination light from the light source (1) is used by opening and closing the shutter with the shutter (5). When the shutter (5) is closed, the illumination light reflected from the shutter is A first photoelectric detector (32A) for receiving light, a light beam splitting member (14) for splitting a part of the illumination light passing through the shutter (5), and a second photoelectric sensor for receiving the light beam split by the light beam splitting member. A detector (16) and a light source (1) according to detection signals of the first photoelectric detector and the second photoelectric detector.
And a control system (26) for controlling the output of.

In the second light source device of the present invention as well, if, for example, a wavelength selecting member is installed after the shutter (5), the reflected light from the wavelength selecting member when the shutter (5) is opened. Returns to the light source (1) side.
Therefore, in the present invention, the illumination light from the light source (1) can be received even when the shutter (5) is closed or is being closed, and a position not affected by the return light, that is, the shutter (5). The first photoelectric detector (32A) is arranged at a position where the illumination light from the light source (1) is reflected by the shutter (5) when is closed. This first photoelectric detector (32
Since the return light from the wavelength selection member or the like does not enter A), for example, when the shutter (5) is closed, the return signal is obtained by multiplying the detection signal of the first photoelectric detector (32A) by a predetermined correction coefficient. The output of the light source (1) is controlled so that the output signal is at a predetermined level and the detection signal of the second photoelectric detector (16) is at a predetermined level when the shutter (5) is open, so that a stable output is obtained. can get.

In this case, the control system is, for example, the first system.
The output of the light source (1) may be controlled so that the sum of the detection signals of the photoelectric detector (32A) and the second photoelectric detector (16) becomes a predetermined value. Finding the sum is the first
Assuming that the detection signal of the photoelectric detector (32A) is Yt and the detection signal of the second photoelectric detector (16) is It, for example, using a correction coefficient k corresponding to the reflectance of the shutter (5), This means that the sum I of the detection signals corrected by the coefficient k is obtained.

I = It + k · Yt The sum I of the detection signals is a signal proportional to the total amount of illumination light from the light source (1) even when the shutter (5) is opening or closing. Therefore, by controlling the light source (1) so that the sum I becomes a predetermined level, the output of the light source (1) is always stabilized.

An exposure apparatus according to the present invention includes the above-described light source device according to the present invention, and a stage system (23, 28) for positioning the mask (R) and the substrate (W). The mask (R) is illuminated with the provided illumination light, and the pattern of the mask (R) is transferred onto the substrate (W) under the illumination light. According to the exposure apparatus of the present invention, since the output of the light source can be controlled stably, the exposure amount control accuracy for the substrate (W) can be increased.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a projection exposure apparatus used in this embodiment. In FIG. 1, a light emitting portion (arc portion) of an ultra-high pressure mercury lamp (hereinafter simply referred to as “mercury lamp”) 1 is a first focal point of an elliptical mirror 2. Illumination light from the mercury lamp 1 which is arranged nearby is condensed by the elliptical mirror 2 and is incident on the beam splitter 3 having a large reflectance and a small transmittance. The illumination light IL1 transmitted through the beam splitter 3 is condensed by a condenser lens 31 and is incident on a light receiving surface of a mercury lamp output sensor 32 including a photoelectric detector such as a photodiode.

On the other hand, the illumination light IL2 reflected by the beam splitter 3 is reflected by a mirror 4 for bending the optical path, and is then arranged near the second focal point of the elliptical mirror 2 and a plurality of blades are arranged at equal angular intervals. And enters the shutter 5. Each blade of the shutter 5 is approximately 45 degrees with respect to the optical axis AX1 of the illumination system.
And is rotated by a drive motor 6 so as to cross the optical axis AX1. A rotary encoder 41 for detecting the rotation angle of the shutter 5 is mounted on the rotation axis of the shutter 5. Based on a detection signal of the rotary encoder 41, the rotation angle of the shutter 5 and, consequently, the opening / closing degree (for the incident light amount) (The ratio of the amount of light passing therethrough).

When the shutter 5 is open, the shutter 5
The illumination light IL2 that has passed between the blades of the
The illumination light other than the i-line is removed. Actually, most of the illumination light such as the h-line and the g-line near the i-line is reflected and returned to the shutter 5 side. In addition, since infrared rays transmitted through the interference filter 7 are almost absorbed in the process of passing through a large number of lenses in the illumination system, it is not particularly necessary to provide an infrared absorption filter. I transmitted through the interference filter 7
Exposure light IL consisting of lines is input to the first input lens 8A,
The mirror 9 for bending the optical path, and the fly-eye lens 10 which becomes a substantially parallel light beam through the second input lens 8B
Incident on. An aperture stop plate 11 of an illumination system is rotatably disposed on the exit surface of the fly-eye lens 10, and a normal circular aperture stop 13 is provided around a rotation axis of the aperture stop plate 11.
A, an aperture stop 13B for a deformed light source composed of a plurality of eccentric small apertures, an annular stop 13C, and the like are formed. Then, by rotating the aperture stop plate 11 by the drive motor 12, a desired illumination system aperture stop can be set on the exit surface of the fly-eye lens 10.

A part of the exposure light IL that has passed through the aperture stop on the exit surface of the fly-eye lens 10 is
After being reflected by the integrator sensor 1 including a photoelectric detector such as a photodiode via a condenser lens 15
6 is incident. The exposure light IL transmitted through the beam splitter 14 passes through a first relay lens 17A, a projection type reticle blind (variable field stop) 18, a second relay lens 17B, a mirror 19 for bending an optical path, and a condenser lens 20. The reticle R is illuminated. Exposure light IL
, The image of the pattern 21 on the reticle R is projected onto the wafer W via the projection optical system PL. A photoresist is applied on the wafer W.

Here, the Z axis is taken in parallel with the optical axis AX of the projection optical system PL, and the orthogonal coordinate system of a plane perpendicular to the Z axis is represented by the X axis.
Assuming the Y axis, the reticle R is held on a reticle stage 28 for positioning in the X, Y, and rotation directions. Further, the wafer W is held by suction on the wafer holder 22, and the wafer holder 22 is fixed on the wafer stage 23. The wafer stage 23 corrects the position and the tilt angle of the wafer W in the Z direction and projects the surface of the wafer W onto the projection optical system. System PL
And the stepping and positioning of the wafer W in the X and Y directions. After the exposure of a certain shot area on the wafer W is completed, the operation of stepping the wafer stage 23 and moving the shot area to be exposed next to the exposure field to perform exposure is performed by a step-and-repeat method. The exposure is repeatedly performed on each shot area on the wafer W. Also, since the photoresist on the wafer W has an appropriate exposure amount,
When exposing each shot area, it is necessary to control the exposure amount.

FIG. 2 shows the exposure control mechanism of this embodiment. In FIG. 2, the detection signal Yt output from the mercury lamp output sensor 32 and amplified via the amplifier 24A is
It is taken into an exposure control system 26 composed of a computer via an A / D converter 25A. Similarly, the detection signal It output from the integrator sensor 16 and amplified via the amplifier 24B is also taken into the exposure control system 26, and the exposure control system 26 detects the detection signal from the mercury lamp output sensor 32. The mercury lamp 1 is caused to emit light via the power supply 27 so that a signal (details described later) obtained by correcting Yt using the detection signal It of the integrator sensor 16 becomes a predetermined level. Further, when exposing each shot area on the wafer W, the exposure control system 26 opens the shutter 5 via the drive motor 6 and then integrates the detection signal It of the integrator sensor 16 so as to accumulate on the wafer W. The integrated exposure amount is monitored, and the shutter 5 is closed via the drive motor 6 when the integrated value reaches a predetermined level.

Further, a detection signal of the rotary encoder 41 mounted on the shutter 5 is also supplied to the exposure control system 26, and the exposure control system 26 is configured so that the degree of opening and closing of the shutter 5 can be recognized from the detection signal. ing. next,
An example of a method for controlling the output of the mercury lamp 1 of the present embodiment will be described. In FIG. 1, each blade of the shutter 5 has an optical axis AX1.
, The light from the mercury lamp 1 is all laterally reflected by the shutter 5 when the shutter 5 is closed.
It does not return to the mercury lamp 1. When the shutter 5 is open, the illumination light IL2 that has passed through the shutter 5 enters the interference filter 7. The interference filter 7 of this example has an optical axis A
The illumination light IL3 in a wavelength range other than the i-line reflected from the interference filter 7 when the shutter 5 is open is arranged along the optical axis AX1 because the illumination light IL3 is arranged so as to be substantially perpendicular to X1. Is reflected back to the elliptical mirror 2,
The illumination light (return light) IL3 reflected by the elliptical mirror 2 again enters the beam splitter 3, and a part of the light passes through the beam splitter 3 and enters the mercury lamp output sensor 32.

During the opening and closing operation of the shutter 5, a part of the reflected light of the interference filter 7 is reflected on the back surface of the shutter 5 and does not return to the mercury lamp output sensor 32. Therefore, before the exposure operation is performed, the value I of the detection signal It of the integrator sensor 16 in a state where the shutter 5 is closed.
c, the value Yc of the detection signal Yt of the mercury lamp output sensor 32, the value Io of the detection signal of the integrator sensor 16 with the shutter 5 opened, and the value Yo of the detection signal of the mercury lamp output sensor 32 are measured. Keep it. For this purpose, for example, the shutter 5 is repeatedly opened and closed for a predetermined time before actual exposure of the wafer, and the average value of the detection signals of the sensors 16 and 32 in the open state and the closed state of the shutter 5 during that time is obtained. Good.

The values Ic, Io, Yc and Yo of the detection signals of the sensors 16 and 32 are stored in the storage unit of the exposure control system 26 shown in FIG. Then, at the time of exposure, an exposure amount control system 2
In 6, the detected signal Yt ′ of the mercury lamp output sensor 32 after correction is classified as follows based on the detection signal It of the integrator sensor 16 and the detection signal Yt of the mercury lamp output sensor 32 at a certain time t. And calculate.

Here, the correction start value and the correction end value of the detection signal It of the integrator sensor 16 determined in advance are Is and Ie (Ie> Is), respectively. (When It> Ie) Yt ′ = Yt− (Yo−Yc) (1) (When Ie ≧ It> Is) Yt ′ = Yt− (Yo−Yc) × (It−Is) / (Ie−Is) (2) (When Is ≧ It) Yt ′ = Yt (3)

This is because the detection signal It of the integrator sensor 16 is larger than the correction end value Ie.
Is substantially open), the value obtained by subtracting the variation (Yo−Yc) from the detection signal Yt of the mercury lamp output sensor 32 as in equation (1) is used, and the detection signal It of the integrator sensor 16 is used as the correction start value. In the range of Is or less (the shutter 5 is almost closed), the detection signal Yt of the mercury lamp output sensor 32 is used as it is as shown in Expression (3), and the change (Yo) is intermediately shown in Expression (2). This means that a value obtained by subtracting an amount obtained by proportionally dividing −Yc) by the detection signal It of the integrator sensor 16 from the detection signal Yt of the mercury lamp output sensor 32 is used. And an exposure control system 2
6 supplies power to the mercury lamp 1 via the power supply 27 so that the corrected detection signal Yt ′ is maintained at a predetermined level. Even if the return light from the interference filter 7 in FIG. 1 is incident on the mercury lamp output sensor 32, the detection signal Yt 'after the correction is stable, so that the mercury lamp 1 is turned on using the detection signal Yt'. As a result, the output of the mercury lamp 1 becomes stable even during the opening / closing operation of the shutter 5, and each shot area on the wafer W can be exposed with an appropriate exposure amount.

More specifically, a result of turning on the mercury lamp 1 by setting the correction start value Is and the correction end value Ie of the detection signal It of the integrator sensor 16 as follows will be described. Is = Ic + 0.50 × (Io−Ic) (4) Ie = Ic + 0.90 × (Io−Ic) (5)

In this case, the detection signal It of the integrator sensor 16 and the detection signal Yt of the mercury lamp output sensor 32 have changed as shown in FIGS. 3A and 3B, respectively. The horizontal axis of each drawing in FIG. 3 is the elapsed time T (ms), and the vertical axis is the signal level. As can be seen from FIG.
The detection signal Yt of the mercury lamp output sensor 32 is high due to the influence of the return light during the period when the shutter 5 is open (the period when the level of the detection signal It is high).
When the output of the mercury lamp 1 is controlled so that the detection signal Yt becomes constant, the output of the mercury lamp 1 becomes unstable.

On the other hand, using the correction start value Is and the correction end value Ie of the equations (4) and (5), the corrected detection signal Yt calculated from the equations (1) to (3). '
As shown in FIG. 3C, the detection signal Y shown in FIG.
The change amount of the signal is about 1/3 or less as compared with t. Therefore, by controlling the output of the mercury lamp 1 so that the corrected detection signal Yt 'is constant, the output fluctuation of the mercury lamp 1 is reduced to about 1/3 or less, and high exposure amount control accuracy is obtained.

In the above-described embodiment, the calculation formula of the corrected detection signal Yt 'is not limited to the formulas (1) to (3). For example, the correction start value Is of the detection signal It,
As for the correction end value Ie, if the relationship of Ie> Is is satisfied, the correction start value Is becomes Ic− (Io−I
c) to the correction end value Ie in the range of Ic + (Io−Ic).
May be set in the range of Ic to Ic + 2 (Io−Ic).

As a correction equation when Ie ≧ It> Is, a trigonometric function such as the following equation may be used instead of equation (2). Yt ′ = Yt−0.5 × (Yo−Yc) × [1-cos {π (It−Is) / (Ie−Is)}] (6) Further, a correction formula for calculating the signal Yt ′. In general, if the correction value subtracted from the detection signal Yt of the mercury lamp output sensor 32 is a function that increases as the intensity of light transmitted through the shutter 5 increases,
Any type such as a high-order polynomial may be used.

Note that, in the above-described embodiment, the expression (1) to the expression (1) are used by using the detection signal It of the integrator sensor 16.
The correction of the detection signal Yt is performed by the equation (3) and the like. However, in this example, since the rotary encoder 41 that detects the rotation angle of the shutter 5 is provided, the relationship between the rotation angle θt of the shutter 5 detected by the rotary encoder 41 and the transmitted light amount of the shutter 5 is obtained in advance. Thus, the amount of transmitted light of the shutter 5 can be calculated from the rotation angle θt,
That is, the detection signal It of the integrator sensor 16 can be estimated. Therefore, the detection signal It is the correction start value I
Assuming that s and the rotation angle θt of the shutter 5 when taking the correction end value Ie are θs and θe, respectively, the exposure amount control system 26 uses the rotation angle θt of the shutter 5 obtained from the detection signal of the rotary encoder 41 based on the rotation angle θt. , Formula (1)
The corrected detection signal Yt ′ may be calculated using the same equation as the equation (3). This also stabilizes the output of the mercury lamp 1 as in the case where the detection signal It of the integrator sensor 16 is used.

In the above embodiment, the mercury lamp output sensor 32 receives the luminous flux transmitted through the beam splitter 3. For example, the beam splitter 3 is used as a mirror and the mirror and the mercury lamp 1 are arranged on opposite sides. A mercury lamp output sensor 32 may be provided. Even in this arrangement, the mercury lamp output sensor 32 can monitor the illumination light of the mercury lamp 1 irrespective of the opening and closing of the shutter 5, and the effect of the return light from the interference filter 7 is reduced by performing the above-described output correction.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is also an embodiment for eliminating the influence of the return light from the interference filter 7, and in FIG. 4, the portions corresponding to FIG. 1 are denoted by the same reference numerals and the detailed description thereof will be omitted. FIG. 4 shows a projection exposure apparatus according to the present embodiment. In FIG. 4, illumination light IL2 emitted from a mercury lamp 1 and condensed by an elliptical mirror 2 includes a mirror 3A and a mirror 4
And reaches the shutter 5 disposed near the second focal point of the elliptical mirror 2. When the shutter 5 is open, the illumination light IL2 that has passed through the shutter 5 passes through the interference filter 7, the fly-eye lens 10, and the like, and then becomes the exposure light IL via the beam splitter 14 and the condensing lens 15, and the integrator sensor 16 Is received at. The integrator sensor 16 is a photoelectric detector for light transmitted through the shutter 5.

On the other hand, when the shutter 5 is closed, the blades of the shutter 5 intersect at 45 ° with the optical axis AX1 of the illumination system.
Numeral 2 goes outward almost perpendicularly to the optical axis AX1, and enters one end of an optical fiber 44 via a condenser lens 42 and an interference filter 43 that selects an i-line like the interference filter 7. The other end of the optical fiber 44 is branched into two, and the illumination light having the same wavelength as the exposure light IL emitted from the first end 44a emits a mercury lamp output sensor 32A composed of a photoelectric detector such as a photodiode. Incident on. The mercury lamp output sensor 32A is a photoelectric detector for reflected light from the shutter 5.

A reference mark member 45 made of a glass substrate is fixed near the wafer holder 22 on the wafer stage 23 of the present embodiment, and the surface of the reference mark member 45 is set at the same height as the surface of the wafer W. I have. Further, a slit-shaped opening pattern 46 is formed in the chromium film on the surface of the reference mark member 45. Then, the optical fiber 44
The illumination light having the same wavelength as the exposure light IL emitted from the second end portion 44b is guided into the wafer stage 23 and illuminates the opening pattern 46 from the bottom surface. By moving this opening pattern 46 into the exposure field of the projection optical system PL,
The image of the opening pattern 46 is re-projected onto the opening pattern 46 via the projection optical system PL and the reticle R, and the amount of light that has passed through the opening pattern 46 is received by an internal photoelectric detector, whereby the projection optical system PL Is configured to be able to detect the image plane.

The other structure is the same as that of the embodiment of FIG. 1, and the exposure control mechanism is also the same as that of FIG. However, in FIG. 2, instead of the mercury lamp output sensor 32, FIG.
A mercury lamp output sensor 32A for reflected light is used. Next, an example of a method for controlling the output of the mercury lamp 1 of the present embodiment will be described. In this example, when the shutter 5 is operating, that is, in a half-open state, a part of the illumination light reflected by the shutter 5 can be received by the mercury lamp output sensor 32A, and a part of the illumination light transmitted through the shutter 5 is Light can be received by the integrator sensor 16. Therefore, before the exposure operation is started, the value Ic of the detection signal It of the integrator sensor 16 and the value Yc of the detection signal Yt of the mercury lamp output sensor 32A in a state where the shutter 5 is closed, and a state where the shutter 5 is opened in advance The value Io of the detection signal of the integrator sensor 16 and the value Yo of the detection signal of the mercury lamp output sensor 32 are measured in advance. The values Ic, Io, Yc, and Yo of the detection signals of the sensors 16 and 32A are stored in the storage unit of the exposure control system 26 in FIG.

In this case, when a correction coefficient k corresponding to the reflectance of the shutter 5 is introduced, the total amount of illumination light from the mercury lamp 1 is substantially proportional to the following sum signal I. I = Ic + k × Yc = Io + k × Yo (7) From this equation, the correction coefficient k is as follows. k = (Io−Ic) / (Yc−Yo) (8) Therefore, at the time of subsequent exposure, the exposure control system 26 performs the detection signal It of the integrator sensor 16 and the mercury lamp output sensor 32A at a predetermined sampling rate. And the sum signal I is calculated from the following equation.

I = It + k × Yt (9) The exposure control system 26 in FIG. 2 adjusts the power supplied to the mercury lamp 1 via the power supply 27 so that the sum signal I becomes constant. In this case, the interference filter 7 shown in FIG.
Is reflected by the shutter 5 in the reverse direction and does not enter the mercury lamp output sensor 32A. Therefore, the sum signal I in the equation (9) is almost exactly the total amount of illumination light from the mercury lamp 1 at all times. Changes in proportion to Therefore, by controlling the output of the mercury lamp 1 based on the sum signal I, the output of the mercury lamp 1 can be controlled stably. Specifically, for example, when the output of the mercury lamp 1 is controlled based on only the output signal of the mercury lamp output sensor 32 that detects the illumination light transmitted through the beam splitter 3 as shown in FIG. However, in this example, the output fluctuation of the mercury lamp 1 when opening and closing the shutter 5 could be reduced to 0.5% or less.

In the above embodiment, the light source device of the present invention is applied to a projection exposure apparatus using a projection optical system composed of a refracting system. The light source device of the present invention is composed of a catadioptric system. It is apparent that the present invention can be applied to a projection exposure apparatus using a projection optical system and a proximity type or contact type exposure apparatus not using a projection optical system. As described above, the present invention is not limited to the above-described embodiment, and can take various configurations without departing from the gist of the present invention.

[0042]

According to the first light source device of the present invention, the influence of the return light of the illuminating light passing through the shutter can be corrected using the detection signal of the second photoelectric detector. In the case of using the illumination light from the shutter by opening and closing the shutter, there is an advantage that the output of the light source can be controlled stably even during the opening and closing operation of the shutter.

According to the second light source device of the present invention,
Since the output of the light source is controlled by using the amount of light passing through the shutter and the amount of light reflected by the shutter, when the illumination light from a light source such as a mercury lamp is used by opening and closing the shutter, the shutter is not used. There is an advantage that the output of the light source can be stably controlled even during the opening / closing operation. In addition, the control system
When the output of the light source is controlled so that the sum of the detection signals of the photoelectric detector and the second photoelectric detector becomes a predetermined value, the output of the light source can be stabilized by simple control.

Further, according to the exposure apparatus of the present invention, since the output of the light source can be controlled stably by the light source device of the present invention, high exposure amount control accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a projection exposure apparatus used in a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing an exposure amount control mechanism used in the embodiment.

FIG. 3 is a diagram showing corrected detection signals obtained from detection signals of an integrator sensor 16 and a mercury lamp output sensor 32 in the first embodiment.

FIG. 4 is a perspective view showing a schematic configuration of a projection exposure apparatus used in a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mercury lamp 2 Elliptical mirror 3 Beam splitter 3A mirror 5 Shutter 7 Interference filter 10 Fly-eye lens 11 Illumination system aperture stop plate 14 Beam splitter 15 Condenser lens 16 Integrator sensor 18 Projection type reticle blind R Reticle PL Projection optical system W Wafer 31 Condensing lens 32, 32A Mercury lamp output sensor 41 Rotary encoder 44 Optical fiber

Claims (4)

[Claims] 1. A light source device comprising: a light source for generating illumination light; and a shutter for opening and closing an optical path of the illumination light from the light source, wherein the shutter uses the illumination light from the light source for opening and closing. A first photoelectric detector that receives a part of the illumination light from the light source without passing through the shutter; a light beam branching member that branches a part of the illumination light that has passed through the shutter; A light source, comprising: a second photoelectric detector that receives the emitted light beam; and a control system that controls an output of the light source in accordance with detection signals of the first photoelectric detector and the second photoelectric detector. apparatus. 2. A light source device comprising: a light source for generating illumination light; and a shutter for opening and closing an optical path of the illumination light from the light source, wherein the shutter uses the illumination light from the light source for opening and closing. A first photoelectric detector that receives illumination light reflected from the shutter when the shutter is closed; a light beam branching member that branches a part of the illumination light that has passed through the shutter; A second photoelectric detector that receives the emitted light beam; and a control system that controls an output of the light source in accordance with detection signals of the first photoelectric detector and the second photoelectric detector. Light source device. 3. The light source device according to claim 2, wherein the control system controls an output of the light source so that a sum of detection signals of the first photoelectric detector and the second photoelectric detector becomes a predetermined value. A light source device characterized by controlling. 4. A light source device according to claim 1, further comprising: a stage system for positioning a mask and a substrate; illuminating the mask with illumination light opened and closed by the light source device; An exposure apparatus, wherein the pattern of the mask is transferred onto the substrate under the illumination light.