JP2003218013A - Measurement image pick-up device and measuring method, aligner and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an accuracy in the optical measurement of an aligner. <P>SOLUTION: This measurement image pick-up device is used as an optical measuring device of an aligner and equipped with a plurality of image pick-up units, a measurement processing unit, and a power control unit. The image pick-up units are annexed to the optical unit of the aligner to image an object with their own timing. The measurement processing unit enables image signals picked up by the image pick-up units to undergo measurement signal processing to generate measurement data for the aligner. On the other hand, the power control unit carried out the power control of the image pick-up units in accordance with the operation timing of the image pick-up units. That is, the power control unit feeds an electrical power necessary for an image pick-up operation to the image pick-up units in operation. The power control unit stops feeding a power to the image pick-up unit not in operation or reduces a power supplied to the image pick-up unit not in operation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device which is mounted on an exposure apparatus which projects an exposure pattern onto an exposure target (for example, a semiconductor element, a liquid crystal element, a magnetic head, etc.) and which is used for optical measurement of the exposure apparatus. The present invention relates to an imaging device. The present invention relates to a method of optical measurement of an exposure apparatus. The present invention relates to an exposure apparatus. The present invention relates to an exposure method for projecting an exposure pattern on an exposure target.

[0002]

2. Description of the Related Art An exposure apparatus (so-called stepper) for exposing and transferring an exposure pattern is used in the manufacture of semiconductor elements, liquid crystal elements and the like. Since this type of exposure apparatus projects a fine exposure pattern precisely, extremely high optical accuracy is required. Therefore, for example, in a reduction projection type exposure apparatus made in 1997, the tolerance of the surface accuracy of the projection optical system was 1 / 100,000 mm or less for a lens with a diameter of 200 mm (this is on a baseball field with a diameter of 120 m). , 0.006 mm, which corresponds to the accuracy that allows only unevenness). Also, when positioning the exposure target,
Extremely high alignment accuracy of several tens of nm is required. Therefore, a precise optical design is made in consideration of the altitude and climate of the delivery destination of the exposure apparatus.

[0003]

By the way, such an exposure apparatus includes a projection optical system for projecting an exposure pattern,
An alignment optical system for position control is provided. An imaging device for measurement is attached to these optical systems. Naturally, such a measurement image pickup apparatus is also required to have extremely high accuracy as described above.

However, there is a concern that such heat generation of the measurement image pickup device may cause a disturbance and disturb the optical accuracy of the exposure device. Such an adverse effect becomes a serious obstacle in further improving the resolution of the exposure apparatus. Therefore, it is an object of the present invention to improve accuracy irregularity caused by such a measurement image pickup device.

[0005]

In order to solve the above problems, the present invention is configured as follows. <Claim 1> The invention according to claim 1 is a measurement imaging device used for optical measurement of an exposure apparatus, and includes a plurality of imaging units and power control. Among these, the plurality of imaging units images the light emitted from the optical unit at individual timings. On the other hand, the power control unit controls the power of the imaging unit according to the operation timing of the plurality of imaging units. That is, the power control unit supplies the power required for the image capturing operation to the image capturing unit during image capturing. In addition, the power control unit "stops the supply of power" to the image capturing unit when the image is not captured.
Or carry out "power reduction". <Claim 2> According to a second aspect of the present invention, in the measurement image pickup apparatus according to the first aspect, each image pickup unit outputs a two-dimensionally arranged light receiving element array and an output of the light receiving element array for each vertical column. And a horizontal transfer unit that horizontally transfers the output transferred by the vertical transfer unit. The power control unit stops the power supply to the horizontal transfer unit at the timing of non-imaging. <Claim 3> The invention according to claim 3 is the measurement image pickup apparatus according to any one of claims 1 and 2, wherein each image pickup unit power-amplifies a picked-up image signal. Have respectively. The power control unit stops the power supply to the output amplifier at the timing of non-imaging. <Claim 4> According to a fourth aspect of the invention, in the measurement image pickup apparatus according to any one of the first to third aspects, a plurality of image pickup sections are individually arranged, and the optical units are different from each other. Image signals for measuring optical characteristics are individually generated. <Claim 5> The invention according to claim 5 is a method for measuring optical characteristics of an optical system of an exposure apparatus, which comprises an imaging step,
And a power control step. Of these, in the imaging step, the plurality of imaging units are driven at individual timings, the light emitted from the optical system is received, and the image signals for optical measurement are respectively generated. On the other hand, in the power control step, the power control of the image pickup unit is executed at the drive timing of the image pickup unit in the image pickup step. That is, in this case,
Electric power required for the image capturing operation is supplied to the image capturing unit during image capturing. In addition, “non-imaging of power” or “reduction of power” is performed on the imaging unit during non-imaging. <Claim 6> According to a sixth aspect of the present invention, in the measurement method according to the fifth aspect, each imaging unit has a two-dimensionally arrayed light receiving element array and an output from the light receiving element array for each vertical column. It has a vertical transfer unit for vertical transfer and a horizontal transfer unit for horizontal transfer of the output transferred by the vertical transfer unit. In the power control step, power is supplied to the horizontal transfer unit of the imaging unit during non-imaging. It is characterized by stopping. <Claim 7> According to a seventh aspect of the present invention, in the measurement method according to any one of the fifth to sixth aspects, each imaging unit includes an output amplifier that power-amplifies a captured image signal. The power control step is characterized in that the power supply to the output amplifier of the imaging unit is stopped during non-imaging. <Claim 8> The invention according to claim 8 is the measurement method according to any one of claims 5 to 7, wherein the optical system forms an image of the pattern formed on the mask on the substrate. It is characterized in that it includes a projection optical system for projecting, and measures information on the aberration of the projection optical system based on the image signal generated in the imaging step. <Claim 9> The invention according to claim 9 is the measurement method according to any one of claims 5 to 8, wherein the optical system forms an image of the pattern formed on the mask on the substrate. It is characterized in that it includes a projection optical system for projecting, and measures information about a pupil shape of the projection optical system based on the image signal generated in the imaging step. <Claim 10> The invention according to claim 10 is an exposure apparatus for transferring a pattern formed on a mask onto a substrate through a projection optical system, and the invention is any one of claims 1 to 4. The measurement image pickup device according to the item 1 is used to have a measurement processing unit that performs predetermined measurement signal processing on image signals picked up by a plurality of image pickup units to generate measurement data. The exposure control is performed based on << Claim 11 >> The invention according to Claim 11 is Claim 1
In the exposure apparatus described in 0, the optical characteristic of the projection optical system is measured by using the measurement imaging device, and the optical characteristic of the projection optical system is adjusted based on the measured optical characteristic. <Claim 12> The invention according to claim 12 is an exposure method for transferring a pattern formed on a mask onto a substrate through a projection optical system, and uses the measurement method according to claim 8. It is characterized in that it has an adjusting step for adjusting the aberration of the projection optical system based on the aberration information measured by. <Claim 13> The invention according to claim 13 is an exposure method for transferring a pattern formed on a mask onto a substrate through a projection optical system, and uses the measurement method according to claim 9. It is characterized in that it has an adjusting step for adjusting the pupil shape of the projection optical system based on the pupil shape information measured by.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an exposure apparatus (including a measurement image pickup apparatus) according to this embodiment. In FIG. 1, Z is shown in the normal direction of the wafer W to be exposed.
The axis is set, the Y axis is set in the direction parallel to the paper surface in the plane of the wafer W, and the X axis is set in the direction orthogonal to the paper surface in the plane of the wafer W. Further, in FIG. 1, in order to measure the optical characteristics of the projection optical system PL, the imaging unit S
Is inserted (attached) in the optical path of the projection optical system PL.

In the exposure apparatus shown in FIG. 1, the exposure light is, for example, 248 nm (KrF) or 193 nm.
A light source 1 that emits light of wavelength (ArF) is arranged. The substantially parallel light beam emitted from the light source 1 is shaped into a light beam having a predetermined cross section through the beam shaping optical system 2 and then reaches the coherence reduction unit 3. The coherence reduction unit 3 reduces an interference pattern generated on the mask surface M (and hence the wafer W) that is the surface to be irradiated, and is disclosed in, for example, Japanese Patent Laid-Open No. 59-2263.
No. 17 publication.

The light flux that has passed through the coherence reducing section 3 is converged at multiple points via the first fly-eye lens 4 and forms a large number of light spots (pseudo light sources) on the focal plane on the rear side. Light fluxes from these many light spots reach the second fly-eye lens 7 via the vibrating mirror 5 and the relay optical system 6. Here, the vibrating mirror 5 is a bending mirror that rotates around the X axis, and has a function of reducing an interference pattern that occurs on the illuminated surface.

The second fly-eye lens 7 converges the light beam at multiple points and forms a large number of light spots (pseudo-planar secondary light sources) on the focal plane on the rear side. The light flux from the secondary light source, through the aperture stop 8 and the condenser optical system 9, illuminates the mask M having a predetermined exposure pattern on the lower side surface substantially uniformly. The light flux that has passed through the mask M is projected via the projection optical system PL to form an optical image of a predetermined exposure pattern on the wafer W.

The wafer W is vacuum chucked by the wafer holder WH on the wafer stage WS. The wafer stage WS is position-controlled with nano-order accuracy by a wafer stage controller (not shown). The exposure apparatus shown in FIG. 1 includes an off-axis alignment optical system for detecting the position of the wafer W on the XY plane. For example, a halogen lamp (not shown) is attached to the alignment optical system as a light source that supplies illumination light having a wide wavelength band. Illumination light from this light source is transmitted to the relay optical system (not shown) and the light guide 2.
Injected via 1. The illumination light thus emitted enters the half prism 24 via the condenser lens 22 and the relay lens 23.

The illumination light reflected by the half prism 24 is incident on the alignment mark on the wafer W by epi-illumination via the first objective lens 25 and the reflection prism 26.
The light from the alignment mark passes through the half prism 24 via the reflection prism 26 and the first objective lens 25. The transmitted light is split into two directions by the half prism 28 via the second objective lens 27.

Of the branched light, the light that has passed through the half prism 28 forms an image of an alignment mark on an image pickup section 29 for X-direction image pickup. On the other hand, the light reflected by the half prism 28 forms an image of the alignment mark on the image capturing section 30 for capturing the Y direction. Alignment system control unit 30
a drives the two image pickup units 29 and 30 to individually pick up the images of the alignment marks, and performs signal processing on these two image signals to detect the position of the wafer W on the XY plane. The details of the alignment system are described in, for example, JP-A-4-65603 and JP-A-4-27324.
The details are disclosed in Japanese Patent No.

Further, since the exposure apparatus shown in FIG. 1 detects the position of the wafer W in the Z direction, it is of the oblique incidence type.
A dimensional autofocus (AF) system is provided. The two-dimensional AF system includes, for example, a halogen lamp (not shown) as a light source that supplies illumination light having a wide wavelength band. Illumination light from such a light source is emitted via a relay optical system (not shown) and a light guide 31. The illumination light emitted in this manner is shaped into a substantially parallel light flux via the condenser lens 32, and then enters the deflection prism 33. The deflection prism 33 deflects this parallel light flux. Stripe gratings (slits) in the X direction are formed on the exit surface of the deflection prism 33. The light that has passed through this stripe grating and becomes a stripe pattern is projected onto the projection optical system PL.
It passes through a projection condenser lens 34 which is arranged in parallel with the optical axis. The passing light reaches the wafer W at a predetermined incident angle after passing through the mirror 35 and the projection objective lens 36.

In this way, the primary image of the stripe pattern is formed on the wafer W. The light of this primary image is
Via the light receiving objective lens 37 and the vibrating mirror 38,
It reaches the light-receiving condenser lens 39. Light-receiving condenser lens 3
The light transmitted through 9 forms a secondary image in a stripe pattern on the incident surface of the deflection prism 40. This secondary image is laterally displaced in the stripe pitch direction due to the displacement of the wafer W in the Z direction.

On the other hand, a stripe grating in the X direction is pre-patterned on the incident surface of the deflecting prism 40. The secondary image with lateral displacement is the stripe width (that is, the amount of light) when passing through the slit of this stripe grating.
Changes. The secondary image thus light-modulated is subjected to tilt correction by the deflection prism 40, and then projected onto the image pickup unit 42 via the relay optical system 41.

The image pickup section 42 picks up this projected image and two-dimensionally measures the brightness of the projected image. From this measurement result, the surface position of the wafer W in the Z direction is detected. The surface position of the wafer W can be precisely adjusted by moving the wafer stage WS in the Z-axis direction or rotating around the X-axis or the Y-axis according to the surface position. The exposure apparatus shown in FIG. 1 also includes an image pickup unit S for measuring the wavefront aberration and pupil shape of the projection optical system PL. When the image pickup unit S is used, as shown in FIG. 1, the wafer stage WS moves laterally so that the image pickup unit S is attached to the projection optical system PL.

Further, when measuring the aberration of the image pickup unit S, a test mask TM provided with a test pattern for aberration measurement (for example, a plurality of circular openings) is arranged on the mask stage MS. On the other hand, the image pickup unit S is provided with a marking plate 11 (for example, a glass plate having a light transmission region in the center and alignment marks on the periphery). The light flux of the projection optical system PL, after passing through the sign board 11, reaches the half mirror 14 a via the collimator lens 12 and the relay lens 13. The half mirror 14a splits this light flux into two directions.

That is, the light transmitted through the half mirror 14a reaches the image pickup section 15a. At this time, the imaging unit 15
The pupil shape of the projection optical system PL is formed as an image on the imaging surface of a. The pupil-shaped image signal captured by the image capturing unit 15 a is transmitted to the measurement unit 51 via the drive unit 50. The measurement unit 51 measures the pupil shape of the projection optical system PL by performing signal processing on this image signal.

On the other hand, the light reflected by the half mirror 14a reaches the micro fly's eye 14b. The micro fly's eye 14b spatially divides the reflected light into small wavefronts and forms a secondary image for each wavefront. The large number of secondary images are captured by the image capturing unit 15b for measuring wavefront aberration. The image signal thus captured by the image capturing unit 15b is transmitted to the measurement unit 51 via the drive unit 50. The measurement unit 51 measures the wavefront aberration of the projection optical system PL by processing the image signal. The measurement unit 51 may individually obtain the “spherical aberration”, “coma aberration”, “astigmatism”, etc. of the projection optical system PL by analyzing the Zernike coefficient from this wavefront aberration.

FIG. 2 is a diagram showing a control system of the above-mentioned image pickup units 15a and 15b. This control system is roughly configured by the drive unit 50 and the measurement unit 51 described above. Among them, the drive unit 50 has the following constituent requirements. Correlated double sampling circuit 52a for removing a noise level from the image signal of the image pickup section 15a Correlated double sampling circuit 52b for removing a noise level from the image signal of the image pickup section 15b A / D conversion etc. to the image signal of the image pickup section 15a Output circuit 53a for performing the processing of 5) Output circuit 53b for performing processing such as A / D conversion on the image signal of the image pickup section 15b Horizontal drive for supplying a drive pulse for horizontally transferring the image signal to the image pickup section 15a Circuit 54a Horizontal drive circuit 54b that supplies a drive pulse for horizontally transferring an image signal to the image pickup unit 15b Power supply circuit 55a that supplies a voltage for bias current generation to an output amplifier in the image pickup unit 15a Inside image pickup unit 15b Power supply circuit 55b for supplying a bias current generation voltage to the output amplifier of the two imaging units 15a and 15b, On the other hand the vertical driving circuit 56 supplies driving pulses for direct transfer, the measuring unit 51, two imaging units 15a, 15
The image signal from b is taken in at different timings, and the signal processing for each measurement is executed independently. At this time, the measurement unit 51 adjusts the control signal PWSAVE-a and the control signal PWSA according to the operation timings of the two imaging units 15a and 15b.
The VE-b is output to the drive unit 50.

FIG. 3 is a diagram showing an internal configuration of the horizontal drive circuit 54a and the power supply circuit 55a controlled by the control signal PWSAVE-a. (Note that the internal configurations of the horizontal drive circuit 54b and the power supply circuit 55b are the same as those in FIG. 3 except that the subscript a is replaced with b, and therefore the illustration thereof is omitted here.) In FIG. Horizontal drive circuit 5
4a is a drive pulse generator 61 and a NAND gate group 6
2 to 65. On the other hand, the power supply circuit 55a
Is generally composed of a voltage follower circuit 67 and a CMOS switch 66.

FIG. 4 shows the image pickup section 15 in order to show the whereabouts of the drive pulses of the horizontal drive circuit 54a and the power supply circuit 55a.
It is a figure which shows the internal structure of a. The image pickup unit 15a is roughly configured by a two-dimensionally arranged light receiving element array 71, a vertical CCD 72, a horizontal CCD 73, and an output amplifier 74. (Note that the internal configuration of the image capturing unit 15b is the same as that of the image capturing unit 15a, so illustration thereof is omitted here.)

[Correspondence Relationship with the Invention] Here, the correspondence relationship between the above-described embodiment and the present invention will be described. It should be noted that the correspondence relationship here is one interpretation for reference, and the present invention is not limited to these. The measuring image pickup device according to the claims comprises an image pickup unit S and a drive unit 5.
0 and the measurement unit 51. The plurality of imaging units described in the claims correspond to the imaging unit 15a and the imaging unit 15b. The power control unit described in the claims corresponds to the drive unit 50. The light receiving element array described in the claims corresponds to the light receiving element array 71. The vertical transfer unit described in the claims corresponds to the vertical CCD 72. The horizontal transfer unit described in the claims corresponds to the horizontal CCD 73. The output amplifier according to the claims is
It corresponds to the output amplifier 74. The position control unit described in the claims corresponds to the control unit 30a. The measurement processing unit described in the claims corresponds to the measurement unit 51. The alignment optical system described in the claims corresponds to the first objective lens 25, the second objective lens 27, the half prism 28, and the like.
The exposure unit described in the claims comprises a light source 1, a beam shaping optical system 2,
It corresponds to the first fly-eye lens 4, the second fly-eye lens 7, the condenser optical system 9, and the like. The projection optical system described in the claims corresponds to the projection optical system PL.

[Description of Operation of this Embodiment] The operation of this embodiment will be described below with reference to FIGS. First, the measurement unit 51 alternately performs the pupil shape measurement and the wavefront aberration measurement as follows.

(1) Measurement operation of pupil shape When measuring the pupil shape, the measurement unit 51 uses a control signal.
PWSAVE-a is set to high level and the other control signal
Lower PWSAVE-b to low level. As a result, the horizontal drive circuit 54a outputs the output pulse X of the drive pulse generator 61.
H and XRG invert and pass through the NAND gates 62 and 63. These inverted outputs are two-phase transfer pulses H1,
H2, read pulse LH1, and reset pulse R
Each is shaped into G. The drive pulse shaped in this manner is supplied to the horizontal CCD 73 of the image pickup unit 15a and is used as a power source for horizontal transfer.

The output pulses XSHP and XSHD of the drive pulse generator 61 are inverted and passed through the NAND gates 64 and 65. These inverted outputs are used for timing control of the correlated double sampling circuit 52a. On the other hand, in the power supply circuit 55a, C is generated by the control signal PWSAVE-a.
The MOS switch 66 turns off. As a result, the reference voltage Vgg is output from the voltage follower circuit 67 and supplied to the output amplifier 74 of the imaging unit 15a. The output amplifier 74 generates a bias current by this reference voltage Vgg and uses it as a power source for amplification operation.

By such power supply, the image pickup section 15a
On the side, an image signal indicating the pupil shape is generated. The measurement unit 51 performs signal processing on this image signal to measure the pupil shape. Note that the imaging unit 15b is placed at this time when not imaging. At this time, the control signal PWSAVE-b is set to the low level, so that both the “driving pulse for horizontal transfer” and the “reference voltage Vgg of the output amplifier” are cut off in the horizontal driving circuit 54b and the power supply circuit 55b. . As a result, the electric power supplied from the drive unit 50 to the imaging unit 15b is reduced.

(2) Wavefront Aberration Measuring Operation On the other hand, when measuring the wavefront aberration, the measuring unit 51
The control signal PWSAVE-a is lowered to the low level, and the other control signal PWSAVE-b is raised to the high level. As a result, an operation reverse to that at the time of measuring the pupil shape described above occurs. That is, the image pickup unit 15b is supplied with electric power required for the image pickup operation from the drive unit 50. As a result, the image signal indicating the wavefront aberration is output from the imaging unit 15b. The measurement unit 51 performs signal processing on this image signal to measure the wavefront aberration. On the other hand, on the imaging unit 15a side, the "driving pulse for horizontal transfer" and the "reference voltage V of the output amplifier V"
Any "gg" is blocked. As a result, the electric power supplied from the drive unit 50 to the imaging unit 15a is reduced.

(3) Exposure operation In accordance with the wavefront aberration and the pupil shape thus measured,
The exposure apparatus performs adjustments such as slightly moving the lenses of the projection optical system PL, controlling the pressure between the lenses, and inserting an aberration correcting optical system. By such adjustment, the wavefront aberration of the projection optical system PL is minimized and the pupil shape is optimized. After such adjustment of the projection optical system PL, the exposure apparatus projects the exposure pattern of the mask M onto the wafer W (photosensitive substrate) via the projection optical system PL.

[Effects of this Embodiment] As described above, in this embodiment, the imaging unit 15a for pupil shape measurement,
The imaging unit 15b for measuring wavefront aberration operates alternately. At this time, the "driving pulse for horizontal transfer" and the "reference voltage Vgg of the output amplifier" are cut off in the imaging unit in the non-imaging state. As a result, without hindering the imaging operation,
It is possible to reduce heat generation from the imaging units 15a and 15b as much as possible. Due to this reduction in heat generation, fluctuations in the air flow are reduced, and the accuracy of optical measurement of the exposure apparatus can be further improved.

By the way, in this embodiment, the drive pulse for vertical transfer is continuously supplied to the image pickup section in the non-image pickup state. Therefore, in the imaging unit in the non-imaging state,
Vertical transfer (discharging operation) of ineffective charges is continuously executed.

The operating frequency of such vertical transfer is significantly lower than the operating frequency of horizontal transfer. Therefore,
Even if the vertical transfer operation is continued, the temperature rise of the imaging unit is small,
The adverse effect on the accuracy of optical measurement is small.

Furthermore, by continuing the vertical transfer (discharging operation) of the invalid charges in the image pickup section during non-imaging, it is not necessary to start the vertical transfer of the invalid charges from the beginning when the image pickup is restarted. As a result, it is possible to effectively reduce the time lag before resuming imaging. By shortening the time lag at the time of resuming imaging in this way, two types of measurement processing can be repeated at high speed, and the adjustment time of the projection optical system PL can be shortened.

[Supplementary Notes on the Embodiment] In the above-described embodiment, the "driving pulse for horizontal transfer" and the "reference voltage Vgg of the output amplifier" are applied to the image pickup unit when the image pickup is not performed.
Is shut off. However, the present invention is not limited to this. More generally, in the present invention, it is preferable to reduce the heat generated from the image pickup unit during non-image pickup to the extent that the accuracy of optical measurement can be improved. Therefore, the power supply to the imaging unit during non-imaging may be partially reduced or completely stopped as long as such an effect can be obtained.

Further, in the above-described embodiment, the image pickup units 15a and 15b for performing the optical measurement of the projection optical system PL,
Power is controlled. However, the present invention is not limited to this. For example, the imaging units 29 and 30 attached to the alignment optical system (specifically, the X-direction imaging unit 29 that images the X-direction alignment mark and the Y-direction imaging unit 30 that images the Y-direction alignment mark). The same power control may be implemented for the above). In this case, it is possible to reduce the turbulence of the airflow due to the heat generation of the imaging units 29 and 30, and it is possible to improve the alignment measurement accuracy.

The alignment system for performing such power control is not limited to the off-axis type alignment system as shown in FIG. For example, the projection optical system P
An alignment system that takes an image of the alignment mark of the wafer W (or the reference mark on the wafer stage WS) via L, the alignment mark of the mask M and the alignment mark of the wafer W (or the wafer stage W).
The present invention may be applied to an alignment system in which a reference mark on S) is superimposed and imaged.

The present invention is not limited to the exposure apparatus of the type shown in FIG. In general, the present invention is applicable to a measurement image pickup apparatus having a plurality of image pickup units, or an exposure apparatus in which the measurement image pickup apparatus is mounted.

In this embodiment, the image pickup units 15a and 15b differ in pupil shape and wavefront aberration of the projection optical system PL.
Is measured using. However, the present invention is not limited to this. For example, one image pickup unit generates an image signal for measuring a specific aberration (for example, spherical aberration, coma aberration, astigmatism, etc.), and the other image pickup unit generates an image signal for measuring a pupil shape. May be generated.

[0039]

According to the present invention, a plurality of image pickup portions are provided for optical measurement of the exposure apparatus, and the plurality of image pickup portions are operated at individual timings. At this time, the heat generation from the image pickup unit is reduced without hindering the image pickup operation by controlling the power supply to the image pickup unit at the time of non-image pickup so as to stop or reduce the power supply. As a result, the fluctuation of the air flow caused by the heat generation of the imaging unit is reduced, and the accuracy of the optical measurement in the exposure apparatus can be further improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exposure apparatus (including a measurement image pickup apparatus) in the present embodiment.

FIG. 2 is a diagram showing a control system of imaging units 15a and 15b.

FIG. 3 is a diagram showing an internal configuration of a horizontal drive circuit 54a and a power supply circuit 55a.

FIG. 4 is a diagram showing an internal configuration of an imaging unit 15a.

[Explanation of symbols]

1 light source 2 beam shaping optics 3 Interference reduction section 4 First fly-eye lens 5 Vibration mirror 6 Relay optical system 7 Second fly-eye lens 8 aperture stop 9 Condenser optical system 12 Collimating lens 13 relay lens 14a Half mirror 14b Micro fly eye 15a, 15b Imaging unit 21 Light Guide 22 Condenser lens 23 relay lens 24 Half prism 25 First Objective Lens 26 Reflective prism 27 Second objective lens 28 Half prism 29,30 Imaging unit 30a control unit 33 deflection prism 34 Condensing lens for projection 37 Light receiving objective lens 40 deflection prism 50 drive unit 51 Measuring unit 52a Correlated double sampling circuit 53a output circuit 54a Horizontal drive circuit 54b Horizontal drive circuit 55 Power circuit 55a power supply circuit 55b power supply circuit 56 Vertical drive circuit 61 Drive pulse generator 66 CMOS switch 67 Voltage follower circuit 71 Light receiving element array 72 Vertical CCD 73 horizontal CCD 74 Output amplifier PL projection optical system M mask S Imaging unit WS wafer stage

Claims (13)

[Claims] 1. A measuring image pickup apparatus used in an exposure apparatus, comprising: a plurality of image pickup sections for picking up light emitted from an optical unit of the exposure apparatus at individual timings; On the other hand, a measurement image pickup apparatus comprising: a power control unit that supplies power necessary for an image pickup operation at the time of image pickup, and stops the supply of power or reduces the power at the time of non-image pickup. 2. The measurement image pickup device according to claim 1, wherein each of the image pickup units has a two-dimensionally arranged light receiving element array, and a vertical transfer unit that vertically transfers an output of the light receiving element array for each vertical column. And a horizontal transfer unit that horizontally transfers the output transferred by the vertical transfer unit, and the power control unit includes, among the plurality of imaging units, the imaging unit at the time of non-imaging, An imaging device for measurement, characterized in that power supply to the horizontal transfer unit is stopped. 3. The measurement image pickup device according to claim 1, wherein each of the image pickup units has an output amplifier that amplifies a picked-up image signal by power, and the power control unit. The image pickup apparatus for measurement is characterized in that the section stops the supply of power to the output amplifier to the image pickup section during non-image pickup among the plurality of image pickup sections. 4. The measuring image pickup apparatus according to claim 1, wherein the plurality of image pickup units are individually arranged, and are for measuring different optical characteristics of the optical unit. An imaging device for measurement, which is characterized by individually generating image signals. 5. A measuring method used for measuring an optical characteristic of an optical system of an exposure apparatus, wherein a plurality of image pickup units are driven at individual timings to receive light emitted from the optical system, An image capturing step for generating image signals for measurement, and an electric power required for the image capturing operation for the image capturing section of the plurality of image capturing sections at the time of image capturing in accordance with the drive timing of the image capturing section in the image capturing step. And a power control step of stopping or reducing the power supply to the imaging unit during non-imaging. 6. The measuring method according to claim 5, wherein each of the imaging units includes a two-dimensionally arranged light receiving element array,
A vertical transfer unit that vertically transfers the output from the light-receiving element array for each vertical column, and a horizontal transfer unit that horizontally transfers the output transferred from the vertical transfer unit, respectively, in the power control step, A measuring method, characterized in that the power supply to the horizontal transfer unit of the image pickup unit at the time of non-image pickup is stopped. 7. The measuring method according to claim 5, wherein each of the image pickup units includes an output amplifier that amplifies a picked-up image signal by power, and the power control step. Then, the measuring method, characterized in that the power supply to the output amplifier of the imaging unit is stopped during the non-imaging. 8. The measuring method according to claim 5, wherein the optical system includes a projection optical system that projects an image of a pattern formed on a mask onto a substrate, A measuring method characterized by measuring information on an aberration of the projection optical system based on the image signal generated in the imaging step. 9. The measuring method according to claim 5, wherein the optical system includes a projection optical system that projects an image of a pattern formed on a mask onto a substrate, A measuring method characterized by measuring information about a pupil shape of the projection optical system based on the image signal generated in the imaging step. 10. An exposure apparatus for transferring a pattern formed on a mask onto a substrate via a projection optical system, the measurement imaging apparatus according to claim 1. A measurement processing unit that performs predetermined measurement signal processing on the image signals captured by the plurality of image capturing units to generate measurement data, and performs exposure control based on the measurement data. An exposure apparatus characterized by the above. 11. The exposure apparatus according to claim 10, wherein an optical characteristic of the projection optical system is measured using the measurement image pickup device, and the optical characteristic of the projection optical system is measured based on the measured optical characteristic. An exposure apparatus characterized by adjusting optical characteristics. 12. An exposure method for transferring a pattern formed on a mask onto a substrate via a projection optical system, which is based on aberration information measured by using the measurement method according to claim 8. An exposure method comprising an adjusting step of adjusting an aberration of the projection optical system. 13. An exposure method for transferring a pattern formed on a mask onto a substrate via a projection optical system, which is based on pupil shape information measured using the measurement method according to claim 9. And an adjusting step for adjusting the pupil shape of the projection optical system.