JP2001143993A - Exposure apparatus and exposure method, light source apparatus, and device manufacturing method - Google Patents

Abstract

(57) [Problem] To maintain high exposure accuracy for a long period of time without frequently replacing optical sensors. SOLUTION: Various optical sensors provided in an exposure apparatus,
For example, the beam monitor in the light source 16, the integrator sensor 46, the reflected light monitor 47, and the illuminometer 5 on the stage 58
9, a light-receiving layer having a light-receiving layer made of a GaN-based semiconductor and having a Schottky electrode provided on one surface thereof and capable of receiving light incident from the electrode side. It consisted of sensors. According to this sensor, the exposure light can be detected with high accuracy and high sensitivity. In addition, since the GaN-based semiconductor has excellent resistance to ultraviolet light, it is possible to effectively suppress deterioration over time and the like. Therefore, by controlling the exposure amount, the imaging characteristics, and the like based on the information of the optical sensor, the exposure accuracy can be maintained at a high level over a long period of time without frequently replacing the optical sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, an exposure method, a light source apparatus, and a device manufacturing method, and more particularly, to an exposure apparatus used in a photolithography process for manufacturing a semiconductor element, a liquid crystal display element, and the like. The present invention relates to an exposure method, a light source device suitable as a light source of the exposure apparatus, and a device manufacturing method including a step of performing exposure using the exposure apparatus and the exposure method.

[0002]

2. Description of the Related Art Conventionally, in a photolithography process for manufacturing a semiconductor device or a liquid crystal display device, etc., a step-and-repeat type reduction projection exposure apparatus (a so-called stepper) or a step-and-step method in which the stepper is improved. A projection exposure apparatus such as an AND-scan type scanning exposure apparatus (a so-called scanning stepper) is mainly used.

The resolution of a projection optical system constituting this type of projection exposure apparatus is R = k × λ / N, as is well known by the Rayleigh equation. A. It is expressed by the relationship. here,
R is the resolution of the projection optical system, λ is the wavelength of the exposure light, A.
Is the numerical aperture of the projection optical system, and k is a constant determined by the process in addition to the resolution of the resist.

[0004] As the integration density of semiconductor elements increases, the resolution required for the projection optical system becomes increasingly finer. To realize this, as can be seen from the above equation, the wavelength of the exposure light becomes shorter and the projection optical system becomes smaller. The so-called high N.N.
A. Efforts are being made to make this happen. In recent years, 248n
m k output wavelength krypton excimer laser (K
An exposure apparatus having a projection optical system having a numerical aperture of 0.6 or more has been put to practical use using an exposure light source of (rF excimer laser), and exposure with a device rule (practical minimum line width) of 0.25 μm has been realized.

Recently, as a light source following the krypton excimer fluoride laser, an argon fluoride excimer laser (ArF excimer laser) having an output wavelength of 193 nm, and a fluorine laser (F) having an output wavelength of 157 nm, which is shorter than this, are used. ₂ lasers) are attracting attention.
If an exposure apparatus using these lasers as a light source for exposure is put into practical use, it is expected that mass production of micro devices having fine patterns ranging from 0.18 μm to 0.10 μm or less in device rule will be possible. And vigorous R & D is being actively pursued.

Incidentally, in the projection exposure apparatus, in order to realize high-precision exposure, it is necessary to perform various measurements using light having an exposure wavelength prior to exposure. For example, exposure control has been performed as follows. That is, the amount of exposure light irradiated on the reticle in front of the projection optical system is measured in advance by a light amount monitor (called an integrator sensor) disposed in the illumination optical system, and the reticle and the reticle are measured behind the projection optical system. The light amount of the exposure light transmitted through the projection optical system is measured by a light amount monitor on the wafer stage, for example, an illuminometer, and the output ratio between the integrator sensor and the illuminometer is obtained in advance. At the time of exposure, the illuminance of the wafer surface (image surface) is estimated from the output value of the integrator sensor using the output ratio, and the exposure amount is feedback-controlled so that the illuminance of the image surface becomes a desired value.

When a laser light source such as an excimer laser light source is used as the light source, the output fluctuates. Therefore, the output fluctuation is detected using a light amount monitor (energy monitor) disposed inside the light source. You also need to do it. Further, in order to detect the imaging characteristic of the projection optical system with high accuracy, it is necessary to perform various measurements using a sensor under light having an exposure wavelength. Furthermore, since the transmittance and the imaging characteristics of the optical system also fluctuate due to the irradiation of the exposure light, it is necessary to detect these fluctuations and correct the exposure amount and adjust the imaging characteristics in consideration of the detection result. is there.

[0008]

However, in a conventional stepper or the like, a photodiode (PD) using a Si semiconductor material or the like is typically used as an optical sensor (light receiving element) for the above various measurements. Wavelength 24
8 nm KrF excimer laser light or 193 nm wavelength A
When an intense energy beam such as rF excimer laser light is used as the exposure illumination light, the deterioration of the Si-based PD becomes remarkable, and the light-receiving surface and its surface are contaminated by surroundings.
The recombination speed of the carrier changes greatly due to surface deterioration, etc.,
For example, most of the carriers generated near the surface disappear rapidly due to surface recombination and do not sufficiently contribute to photocurrent. There was an inconvenience of becoming.

Therefore, in order to maintain high-precision exposure for a long period of time, the above-mentioned optical sensor must be frequently replaced with a new one.

By the way, there are PDs based on many light receiving principles, and one of them is a Schottky barrier type PD. An example of a Schottky barrier type PD that receives ultraviolet light is described in Japanese Patent Application Laid-Open No. 61-91977. PD described in this publication
A is formed on a sapphire substrate through an AlN buffer layer.
An lGaN layer is grown, and a Schottky electrode (an electrode joined so as to form a Schottky barrier) and an ohmic electrode are provided on the GaN layer to constitute a PD.

However, in the PD described in the above publication, light to be received is transmitted from the sapphire substrate to the thick AlGa.
Since the light is guided through the N layer to the back surface of the Schottky electrode and received, the light to be received is AlGa.
It is absorbed by the N layer and sensitivity is reduced. In particular, as the wavelength of the ultraviolet light to be received becomes shorter, that is, as the energy of the light increases and moves away from the band gap of AlGaN, the absorption coefficient of the light in the AlGaN layer sharply increases, and the light is formed by the Schottky junction. In some cases, it may not be possible to reach the depletion layer region or the vicinity thereof.

For these reasons, if the Schottky barrier type PD described in the above publication is used as it is,
It is difficult to detect the KrF excimer laser light or the like.

The present invention has been made in view of such circumstances, and a first object of the present invention is to maintain high exposure accuracy for a long period of time without frequently replacing optical sensors. An object of the present invention is to provide an exposure device and a light source device.

A second object of the present invention is to provide an exposure method capable of transferring a pattern onto a substrate with high line width accuracy.

A third object of the present invention is to provide a device manufacturing method capable of improving the productivity of microdevices with higher integration.

[0016]

Generally SUMMARY OF THE INVENTION The formula In _x Ga _y A
l _z N (0 ≦ X ≦ 1, 0 ≦ Y ≦ 1, 0 ≦ Z ≦ 1, X + Y
+ Z = 1), the group III-V compound semiconductor is
It is called a GaN-based compound semiconductor. The present inventors have made various prototypes of Schottky barrier type light receiving elements, and repeated various light receiving experiments. As a result, the light receiving element using a GaN-based compound semiconductor as a light receiving layer was obtained by devising the shape of the Schottky electrode. also, the latest exposure apparatus ArF excimer laser light source or the next generation or the F ₂ laser light source has attracted attention as a light source of next next-generation exposure apparatus as a light source, a laser plasma light source, wavelength 200nm or less short emanating from SOR like It has been found that sufficient sensitivity and sufficient durability to light having a wavelength can be obtained. The present invention has been made based on such new knowledge, and employs the following configurations.

According to a first aspect of the present invention, there is provided an exposure apparatus for illuminating a mask (R) with an energy beam and transferring a pattern formed on the mask onto a substrate (W). A light-receiving layer made of a first-conductivity-type GaN-based semiconductor, provided on one side of a light-receiving surface (1a) provided inside the housing of the light source and receiving the energy beam; 1) and a Schottky electrode (Q1) provided on the light receiving surface, and a length of a boundary line between a region covered with the Schottky electrode and an exposed region of the light receiving surface. A first optical sensor (16c) having a Schottky barrier type semiconductor light receiving element (17) whose sum is longer than the outer peripheral length of the light receiving surface.
And;

In this specification, a GaN-based semiconductor is
Formula _{In x Ga y Al z N (} 0 ≦ X ≦ 1,0 ≦ Y ≦ 1,0 ≦
This is synonymous with a GaN-based compound semiconductor determined by Z ≦ 1, X + Y + Z = 1). This GaN-based semiconductor has a melting point of 1
It is a stable material with a very high temperature of 200 ° C. or higher and a hardness close to that of diamond.

Since the Schottky barrier type semiconductor photodetector constituting the first optical sensor uses a GaN-based semiconductor, the illuminance is less deteriorated and the crystal band gap is smaller than that of, for example, a Si-based PD. Since it is larger than Si, drift due to heat is also small, and high-precision detection is possible. In other words, gain (output signal) fluctuation can be reduced. Also, even if an opaque electrode is used as a Schottky barrier type PD, the light to be received is composed of a GaN-based semiconductor because it has a structure to receive light from the upper surface side of the Schottky electrode. It is possible to directly enter the depletion layer without passing through the light receiving layer and while being incident from the electrode side. Thereby, it has excellent sensitivity to light having a wavelength of blue to ultraviolet.
In particular, the sensitivity does not decrease even if the wavelength is shortened.
Therefore, by using the first optical sensor having the Schottky barrier type semiconductor light receiving element, it is possible to detect light intensity with high accuracy, high sensitivity, and excellent stability. Also, Ga
N-based semiconductors respond to changes in external conditions such as heat and atmosphere.
Since it is hard to deteriorate as compared with other semiconductor materials such as a Si-based compound semiconductor, the resistance to ultraviolet rays is also improved. (The same applies to each optical sensor in the following claims).

According to this, the first optical sensor can detect the intensity, center wavelength, spectral half width, etc. of the energy beam with high accuracy, high sensitivity, and excellent stability. Deterioration of measurement reproducibility and deterioration over time due to poor sensitivity of the sensor are suppressed, and unnecessary output fluctuation of the first optical sensor is reduced. Therefore, occurrence of an exposure amount control error due to this can be suppressed. . Therefore, the exposure accuracy can be maintained at high accuracy over a long period of time without frequently replacing the first optical sensor. In particular, in the case of a scanning exposure apparatus having a pulse light source such as a laser light source, the energy variation Epσ per pulse is reduced, and the minimum pulse oscillation number n required to achieve the irradiation energy error Eσ allowed during exposure is reduced. Thus, the throughput can be improved by improving the scanning speed (scan speed).

According to a second aspect of the present invention, there is provided an exposure apparatus for illuminating a mask (R) with an energy beam and transferring a pattern formed on the mask onto a substrate (W). A light source (16) provided between the light source and the substrate surface, and a light receiving surface (1a) for receiving the energy beam is provided on one side thereof, the light receiving member comprising a first conductivity type GaN-based semiconductor. A layer (1) and a Schottky electrode (Q1) provided on the light receiving surface,
Of the light-receiving surface, the total length of the boundary line between the area covered with the Schottky electrode and the exposed area is
A second optical sensor (4) having a Schottky barrier type semiconductor light receiving element (17) longer than the outer circumference of the light receiving surface.
6) and;

According to this, it is possible to detect the energy beam with high accuracy, high sensitivity and excellent stability by the second optical sensor. By using the second optical sensor for various measurements, The exposure accuracy can be improved based on the measured value. For example, the second optical sensor guides an energy beam output from a light source to an illumination optical system.
It is used for detecting the displacement of the optical axis between the routing optical system and the illumination optical system, or when there is no beam monitoring mechanism in the light source, the intensity of the energy beam, the central wavelength, the detection of the spectrum half width, etc. It can be used for. Therefore, based on the measurement value of the second optical sensor,
Optical axis alignment can be performed with high accuracy,
By adjusting the oscillation wavelength or narrowing the band with high accuracy, the exposure accuracy can be improved as a result.

In the second aspect of the present invention, as in the third aspect of the invention, the second optical sensor may be an integrator sensor used for estimating the illuminance of an image plane. As in the invention described in Item 4, the second optical sensor may be used to constantly monitor the energy beam. In the former case, deterioration of measurement reproducibility and deterioration over time due to poor sensitivity of the integrator sensor can be suppressed. Accurate estimation of the image plane illuminance becomes possible, and the output of this integrator sensor is used for normalization to prevent fluctuations in the measurement values of other sensors due to fluctuations in the power of the light source. Is also suppressed. Therefore, the exposure accuracy can be maintained at high accuracy over a long period of time without frequently replacing the integrator sensor. In the latter case, the second optical sensor can constantly monitor the state of the energy beam with high accuracy regardless of whether the exposure is performed or not.

Further, since the output of the integrator sensor is used as a reference for other sensors, the accuracy of exposure amount matching with another exposure apparatus (other unit) after calibration using, for example, a reference illuminometer can be maintained for a long time. , The maintenance interval for the calibration can be lengthened, which contributes to the improvement of MTBF (mean time between failures) or MTTR (mean time to repair).

As described above, since the integrator sensor is used for estimating the illuminance of the image plane, the integrated exposure amount on the substrate is set to the target exposure value based on the output of the integrator sensor. It is desirable to further include an exposure amount control device that controls the exposure amount so as to obtain the amount. In such a case, the integrator sensor can detect an energy beam with high accuracy, high sensitivity, and excellent stability, thereby improving the exposure amount control accuracy and, consequently, the pattern line width accuracy formed on the substrate. Becomes possible.

According to the third aspect of the present invention, as in the sixth aspect of the present invention, a projection optical system (PL) for projecting the energy beam emitted from the mask (R) onto the substrate (W). And a light receiving surface (1a) for receiving a reflected light beam from at least one of the substrate and the mask when the energy beam from the light source (16) is irradiated from the mask side toward the projection optical system. Includes a light receiving layer (1) made of a first conductivity type GaN-based semiconductor provided on one side thereof, and a Schottky electrode (Q1) provided on the light receiving surface. A third optical sensor having a Schottky barrier type semiconductor light receiving element in which the total length of the boundary line between the area covered with the key electrode and the exposed area is longer than the outer circumference of the light receiving surface (47) ; It may further comprise a. In such a case, for example, the transmittance of the mask can be measured by the third optical sensor. That is, by irradiating the mask with the energy beam from the light source in a state where the return light from the substrate side can be ignored, by calculating the ratio between the output of the integrator sensor and the output of the third optical sensor at that time, With a predetermined calculation, the reflectance (transmittance) of the mask can be detected with high accuracy.

In this case, the reflectance of the substrate is calculated based on the output of the integrator sensor (46) and the output of the third optical sensor (47). An arithmetic unit (50) for calculating an irradiation amount of the energy beam to the projection optical system (PL) based on an output of the integrator sensor
And an imaging characteristic adjusting device (74a to 74c, 78, 50) for adjusting the imaging characteristic of the projection optical system based on the reflectance and the irradiation amount calculated by the arithmetic device. May be.

In such a case, even if the exposure operation is continued for a long time, the energy beam from the light source is detected with high accuracy by the integrator sensor, and the reflected light from the mask and the projection optical system from the substrate side are detected by the third optical sensor. The energy beam returning after passing through can be detected with high accuracy, and the output of the integrator sensor and the third
The reflectance of the substrate is calculated with high accuracy based on the output of the optical sensor, and the irradiation amount of the energy beam to the projection optical system is calculated with high accuracy based on the output of the integrator sensor. Then, since the imaging characteristic adjustment device adjusts the imaging characteristic of the projection optical system based on the reflectance and the irradiation amount calculated by the arithmetic device, the imaging characteristic caused by the irradiation variation of the projection optical system can be accurately determined. Correction becomes possible.

According to the fifth aspect of the present invention, as in the eighth aspect, a projection optical system (P) for projecting the energy beam emitted from the mask onto the substrate.
L); a substrate stage (58) that holds the substrate and moves at least two-dimensionally; and a second stage that is disposed on the substrate stage and receives the energy beam applied to at least a part of a predetermined illumination field. 4 optical sensors (5
9B), and a transmittance measuring device (46, 59A, 50) for measuring the transmittance of an optical system including the projection optical system (PL) at predetermined intervals using the fourth optical sensor. If provided, the exposure control device (50)
The control of the exposure amount may be further performed in consideration of a change in the transmittance measured by the transmittance measuring device.

In the present specification, the transmittance of the optical system is
For example, when the projection optical system is an all-reflection optical system,
This is a concept including the reflectance. That is, the concept indicates the ratio of light emitted from the optical system to light incident from the optical system.

In such a case, the transmittance of the optical system is measured by a transmittance measuring device at a predetermined interval, for example, every time exposure of a predetermined number of substrates is completed, and the exposure control device measures the transmittance by the transmittance measuring device. Since the exposure amount is controlled in further consideration of the fluctuation of the transmittance, it is possible to control the exposure amount with higher accuracy, and furthermore, perform exposure with higher accuracy.

In this case, as in the ninth aspect of the present invention, the fourth optical sensor (59B) has a light receiving surface (1a) for receiving the energy beam via the projection optical system (PL). Ga of the first conductivity type provided on one side thereof
It includes a light receiving layer (1) made of an N-based semiconductor and a Schottky electrode (Q1) provided on the light receiving surface, and is exposed in a region of the light receiving surface covered with the Schottky electrode. It is desirable to have a Schottky barrier type semiconductor light receiving element (17) in which the total length of the boundary line with the region is longer than the outer circumference of the light receiving surface.

According to a tenth aspect of the present invention, there is provided an exposure apparatus for illuminating a mask (R) with an energy beam and transferring a pattern formed on the mask onto a substrate (W),
A substrate stage (58) holding the substrate and moving at least two-dimensionally; a light receiving surface (1a) arranged on the substrate stage and receiving the energy beam irradiated to at least a part of a predetermined illumination field Includes a light receiving layer (1) made of a GaN-based semiconductor of the first conductivity type provided on one side thereof, and a Schottky electrode (Q1) provided on the light receiving surface. The fifth embodiment includes a Schottky barrier type semiconductor light receiving element (17) in which the total length of the boundary line between the area covered with the key electrode and the exposed area is longer than the length of the outer periphery of the light receiving surface. Optical sensor (59).

According to this, even if the exposure operation is continued for a long time, the energy beam can be accurately detected on the image plane by the fifth optical sensor. It is possible to accurately obtain the illuminance (including the illuminance distribution) on the image plane, or to accurately obtain the projection position of the mask pattern based on the image plane, and adjust the light amount or the position of the mask accordingly. Thus, the exposure accuracy can be maintained at a high level over a long period of time without frequently replacing the fifth optical sensor.

In this case, the configuration of the irradiation amount sensor,
Various uses are conceivable, for example, as in the invention according to claim 11, a projection optical system (PL) that projects the energy beam emitted from the mask (R) onto the substrate (W).
The fifth optical sensor may be a sensor that receives light from a mark arranged on the object plane side of the projection optical system on the image plane side of the projection optical system. In such a case, the projection position of the mask pattern serving as a reference for mask alignment or baseline measurement is obtained based on the measurement value of the fifth optical sensor, or based on the projection position of the mark image or the contrast of the image light flux. For example, it is possible to determine the imaging characteristics of the projection optical system.

Alternatively, when the apparatus further comprises a projection optical system for projecting the energy beam emitted from the mask onto the substrate, the fifth optical sensor may include the projection optical system. It may be a sensor used for measuring the transmittance of an optical system including a system. In such a case, a change in the transmittance of the optical system caused by irradiation of an energy beam having a high energy can be detected with high accuracy, high sensitivity, and stability. By correcting the imaging characteristics of the above or performing exposure amount control in accordance with the transmittance variation, it becomes possible to improve the accuracy of the pattern line width transferred and formed on the substrate at the time of exposure.

Alternatively, as in the invention according to the thirteenth aspect, when the apparatus further comprises a projection optical system for projecting the energy beam emitted from the mask onto the substrate, the fifth optical sensor includes the illumination field. An irradiation amount monitor having the light receiving surface having an area capable of receiving the energy beam applied to the entire surface at one time may be used. In such a case, a good imaging state is maintained by correcting the imaging characteristics in consideration of the irradiation fluctuation of the imaging characteristic of the projection optical system and the irradiation fluctuation of the mask based on the measurement value of the irradiation amount monitor. Becomes possible. In addition, even when the illumination conditions are changed, the irradiation amount monitor can accurately detect the energy beam passing through the projection optical system, so that the basic data of the irradiation variation calculation of the imaging characteristics is corrected accordingly. It is also possible.

Alternatively, when the apparatus further comprises a projection optical system for projecting the energy beam emitted from the mask onto the substrate, the fifth optical sensor may include the substrate stage. (58) the light-receiving layer detachably mounted on the light-receiving layer, the light-receiving layer receiving interference light between the energy beam applied to at least a part of the illumination field and a light beam emitted from a predetermined pinhole; It may be a sensor used to measure the imaging characteristics of the projection optical system. In such a case, the sensor can detect the imaging characteristics of the projection optical system with high accuracy, so that, for example, when assembling the apparatus, when starting up after transport,
This makes it possible to adjust the imaging characteristics of the projection optical system with high accuracy at the time of an emergency recovery operation such as a power failure.

In the exposure apparatus according to the thirteenth or fourteenth aspect, the adjustment (correction) of the image forming characteristic of the projection optical system can be performed completely manually.
As described in the invention described in the above item, the image processing apparatus may further include an imaging characteristic adjustment device that adjusts the imaging characteristic of the projection optical system based on the measurement value of the fifth optical sensor. In such a case, since the imaging characteristic adjustment device automatically adjusts the imaging characteristic of the projection optical system based on the measurement value of the fifth optical sensor, the adjustment operation of the imaging characteristic is at least partially automated. can do.

In the exposure apparatus according to the tenth aspect, as in the sixteenth aspect, the irradiation amount sensor is a reference illuminometer (90) detachably mounted on the substrate stage. Is also good. In such a case, another optical sensor fixed on the substrate stage and frequently irradiated with the energy beam, or another optical sensor constantly irradiated with the energy beam such as an integrator sensor arranged in the illumination optical system Is calibrated with reference to the output of the reference illuminometer, so that the performance of other optical sensors can be maintained for a long time.

In this case, the reference illuminometer may be used for calibrating an exposure amount on a substrate between a plurality of exposure apparatuses. In such a case, calibration (calibration) for matching the exposure amount on the substrate between the devices (illuminance matching) can be performed with high accuracy.

In the sixteenth aspect of the present invention, as in the eighteenth aspect, the fifth optical sensor comprises:
A sensor (59B) that can measure in-plane illuminance in a predetermined illumination field may be used. In such a case, the in-plane illuminance in the predetermined illumination field can be measured with high accuracy by the fifth optical sensor. For example, by moving the substrate stage two-dimensionally, the optical system including the projection optical system can be measured. Irradiation unevenness (illuminance distribution) through the system can be accurately measured on the substrate surface (image surface), and based on the value, illumination unevenness can be accurately adjusted to improve illuminance uniformity. Therefore, the accuracy of the pattern line width transferred and formed on the substrate is improved.

According to a nineteenth aspect of the present invention, there is provided an exposure apparatus which illuminates a mask (R) with an energy beam and transfers a pattern formed on the mask onto a substrate (W) via a projection optical system (PL). A light source (16) for outputting said energy beam; and
A substrate stage (58) that moves three-dimensionally; an irradiation surface (83) is provided on the substrate stage, and an energy beam from the light source transmitted through a predetermined opening (59f) formed in the irradiation surface is transmitted through the substrate stage. A light-receiving surface (1a) for receiving light includes a light-receiving layer (1) made of a first conductivity type GaN-based semiconductor provided on one side thereof, and a Schottky electrode (Q1) provided on the light-receiving surface; A Schottky barrier type semiconductor light receiving element in which a total length of a boundary line between a region covered with the Schottky electrode and an exposed region in the light receiving surface is longer than an outer peripheral length of the light receiving surface. (17),
By relative scanning the image of the measurement pattern formed on the mask and the opening, the second used for detecting information for determining the positional relationship between the mask and the substrate with a maximum of six degrees of freedom. 6 optical sensors (59C).

According to this, the image of the measurement pattern formed on the mask is relatively scanned with the opening formed on the light receiving surface on the substrate stage, and the energy beam from the light source transmitted through the opening is converted into the sixth beam. , The information for determining the positional relationship between the image plane of the mask or the projection optical system and the substrate with a maximum of six degrees of freedom can be detected with high accuracy. For example, when the relative scanning is performed in a two-dimensional XY plane for a plurality of measurement patterns on the mask, the aerial images of the respective measurement patterns are measured based on the output of the sixth optical sensor, and from the measurement results of these aerial images, High-accuracy detection of imaging characteristics in the XY plane direction (a type of information that determines the positional relationship (overlapping offset) between the mask and the substrate in the XY plane) such as the magnification and distortion of the projection optical system. Can be. Further, for example, by changing the position of the substrate stage in the Z direction orthogonal to the XY plane during the relative scanning, or by repeatedly performing the relative scanning while changing the Z position of the substrate stage, for example, the output of the optical sensor The focus offset, the focal position of the projection optical system, the telecentricity, the depth of focus, and the like, which are the reference information for determining the positional relationship in the Z direction between the mask and the substrate based on the change in the contrast of the differential signal of Can be detected. Further, the detection of the focus offset is performed for at least three different measurement marks on the mask, so that the θ between the mask and the substrate can be obtained.
The leveling offset (the shape of the image plane of the projection optical system or the field curvature) serving as a reference for determining the relative positional relationship in the x and θy directions can be detected with high accuracy. Therefore, the magnification of the projection optical system or the like is adjusted according to the above detection result,
By performing the focus leveling control based on the focus offset and the leveling offset, it is possible to improve the overlay accuracy (overlay accuracy) of the mask and the substrate and the line width control accuracy. Also in this case, it is not necessary to frequently replace the sixth optical sensor.

According to a twentieth aspect of the present invention, there is provided an exposure apparatus for illuminating a mask (R) with an energy beam and transferring a pattern formed on the mask onto a substrate (W) via a projection optical system (PL). A substrate stage (58) for holding the substrate and moving at least two-dimensionally; a mark pattern existing in a predetermined illumination field on the mask, and correspondingly present on the substrate stage. An alignment system having a seventh optical sensor that detects a predetermined mark pattern, wherein the seventh optical sensor receives image light fluxes of both mark patterns (1a).
Includes a light receiving layer (1) made of a first conductivity type GaN-based semiconductor provided on one side thereof, and a Schottky electrode (Q1) provided on the light receiving surface. A Schottky barrier type semiconductor light receiving element (1) in which the total length of the boundary line between the area covered with the key electrode and the exposed area is longer than the outer circumference of the light receiving surface.
7).

According to this, for example, the seventh optical sensor constituting the alignment system is provided with a mark pattern existing in a predetermined illumination field on the mask and a predetermined pattern present on the substrate stage corresponding to the mark pattern. By detecting the alignment mark pattern on the substrate as the mark pattern, the so-called TTR (through the reticle) type substrate alignment can be performed in which the substrate is aligned with reference to the mask. . Further, for example, a seventh optical sensor constituting an alignment system may be configured such that a mark pattern existing in a predetermined illumination field on a mask and a reference mark corresponding to the mark pattern existing on the substrate stage. By detecting the reference mark on the mark plate, so-called mask alignment can be performed. Here, “mask alignment” includes detection of a mask position on a mask coordinate system or a projection position of the mask on a substrate coordinate system, and association between the mask coordinate system and the substrate coordinate system.

In this case, for example, it is possible to detect a mark pattern with high accuracy even if light having a wavelength of 200 nm or less is used as an energy beam for exposure and light having a wavelength which is the same as or nearly equal to the exposure wavelength is used as an alignment wavelength. Become. Therefore, according to the present invention, the overlay accuracy can be improved. In this case, the focus offset and the leveling offset (optical characteristics of the projection optical system,
Or image plane shape), and by performing focus leveling control based on this, it is also possible to improve the line width control accuracy. When the alignment system is an image processing type alignment system, the seventh optical sensor may detect either a one-dimensional image or a two-dimensional image. Also in this case, it is not necessary to frequently exchange the seventh optical sensor.

According to a twentieth aspect of the present invention, as in the twenty-first aspect, the seventh optical sensor includes an image sensor (104R) for detecting a projected image of the both mark patterns as a predetermined two-dimensional image. , 104R), and the alignment system may be a mask alignment system (100) for positioning the mask (R).

The invention according to claim 22 is based on claim 1,
The exposure apparatus according to each of the inventions described in 2, 10, 19, and 20, further comprising one or more eighth optical sensors that receive the energy beam, wherein at least one of the eighth optical sensors is A first conductivity type GaN provided with a light receiving surface (1a) for receiving the energy beam on one side thereof;
A light-receiving layer (1) made of a system semiconductor; and a Schottky electrode (Q1) provided on the light-receiving surface. An optical sensor having a Schottky barrier type semiconductor light receiving element (17) having a total length of the boundary line with the light receiving surface longer than the outer peripheral length of the light receiving surface.

According to this, a light receiving layer made of the first conductivity type GaN-based semiconductor is provided on one side of the eighth light sensor, the light receiving surface for receiving the energy beam, and the light receiving layer is provided on the light receiving surface. And a Schottky electrode,
An optical sensor having a Schottky barrier type semiconductor light receiving element in which the total length of the boundary line between the region covered with the Schottky electrode and the exposed region is longer than the outer peripheral length of the light receiving surface, As a result of being able to detect an energy beam with excellent accuracy, high sensitivity, and stability, the exposure amount control accuracy, the overlay accuracy (the mask and the (Including a synchronization error with the substrate) or the improvement of the line width accuracy on the substrate allows the exposure accuracy to be maintained at high accuracy over a long period of time without frequently replacing the optical sensor. In this case, all of the eighth optical sensors are replaced by GaN of the first conductivity type having a light receiving surface for receiving an energy beam provided on one side thereof.
A total length of a boundary line between a region covered with the Schottky electrode and an exposed region of the light receiving surface, including a light receiving layer made of a system semiconductor and a Schottky electrode provided on the light receiving surface. However, in the case of an optical sensor having a Schottky barrier type semiconductor light receiving element longer than the outer circumference of the light receiving surface, the exposure accuracy is most improved by improving the exposure amount control accuracy, the overlay accuracy, or the line width accuracy on the substrate. Can be improved.

In the exposure apparatus according to the present invention, the substrate stage can control the position and orientation of the substrate in at least five degrees of freedom. It is desirable that Here, the directions of five degrees of freedom mean the superposition control axes (X, Y) and the focus / leveling control axes (Z, θx, θy) excluding the in-plane rotation direction (θz direction) of the substrate. The θz direction can be controlled either on the substrate stage side or by driving the mask side. According to the present invention, the relative positional relationship between the mask and the substrate in the directions of six degrees of freedom can be set to a desired relationship.

In the exposure apparatus according to any one of the first to twenty-third aspects, it is preferable that the wavelength of the energy beam is 300 nm or less, as in the twenty-fourth aspect. While it was difficult to detect an energy beam in such a wavelength band with a conventional PD (photodiode) with high sensitivity and stably for a long period of time, the photosensor employed in the exposure apparatus of the present invention is difficult. High precision,
Since it can be detected with high sensitivity and good stability, for example, a KrF excimer laser beam having a wavelength of 248 nm, a wavelength of 1
ArF excimer laser light 93 nm, by performing exposure using an energy beam of the F ₂ laser beam, or it than the short wavelength of 157 nm, the improvement of the resolving power of the projection optical system, it is possible to highly accurate exposure.

According to a twenty-fifth aspect of the present invention, there is provided an exposure method for illuminating a mask with an energy beam and transferring a pattern formed on the mask onto a substrate via a projection optical system. Of the first conductivity type provided on the side
The light receiving portion, which is made of an N-based semiconductor and has a Schottky electrode provided on the light receiving surface, receives the energy beam in a state where a reverse bias is applied, and based on a photocurrent taken out from the light receiving portion to the outside. An exposure method, comprising: a first step of detecting information on the intensity of an energy beam; and a second step of transferring the pattern of the mask on the substrate at a predetermined resolution and a depth of focus using the detected information.

According to this, in the first step, the light-receiving surface is made of a GaN-based semiconductor of the first conductivity type provided on one side thereof, and the light-receiving portion provided with the Schottky electrode on the light-receiving surface is provided with:
An energy beam is received in a state where a reverse bias is applied, and information on the intensity of the energy beam is detected based on a photocurrent extracted from the light receiving unit to the outside. Thereafter, in a second step, a mask pattern is transferred onto the substrate at a predetermined resolution and depth of focus using the detected information. In this case, in the first step, the resistance to ultraviolet light is S
Since information about the intensity of the energy beam is detected using a GaN-based semiconductor that is higher than that of the i-type light receiving element, information about the intensity of the energy beam can be detected with high accuracy over a long period of time. Since the mask pattern is transferred onto the substrate at a predetermined resolution and depth of focus using this information in the second step, the line width accuracy of the pattern transferred and formed on the substrate can be improved.

In the exposure method according to the twenty-fifth aspect of the present invention, as in the twenty-sixth aspect, the first method includes:
The information detected in the step includes at least adjustment of the imaging characteristics of the projection optical system, control of the exposure amount, and adjustment of the relative position between the mask (or the imaging surface of the projection optical system) and the substrate in the second step. One can be used.

The invention according to claim 27 is a light source device used for an exposure apparatus for illuminating a mask with an energy beam and transferring a pattern formed on the mask onto a substrate, and outputs the energy beam. Beam source (16
a) a first conductivity type Ga housed in the same housing as the beam source and having a light receiving surface (1a) provided on one side thereof for receiving the energy beam output from the beam source;
It includes a light receiving layer (1) made of an N-based semiconductor and a Schottky electrode (Q1) provided on the light receiving surface, and is exposed in a region of the light receiving surface covered with the Schottky electrode. An optical sensor (16c) having a Schottky barrier type semiconductor light receiving element (17) having a total length of the boundary line with the region longer than the outer peripheral length of the light receiving surface is provided.

According to this, high accuracy and high accuracy can be obtained by the optical sensor.
It is possible to detect the intensity, center wavelength, spectral half width, etc. of the energy beam with high sensitivity and excellent stability, and to suppress deterioration in measurement reproducibility and deterioration over time due to poor sensitivity of the optical sensor. Unnecessary output fluctuation is reduced, so that the occurrence of an exposure amount control error due to this can be suppressed. Therefore, the exposure accuracy can be maintained at high accuracy over a long period of time without frequently replacing the optical sensor. In particular, when the beam source constituting the light source device of the present invention is a pulse emission source and is applied to a scanning exposure apparatus, the energy variation Epσ per pulse becomes small, and the irradiation energy error Eσ allowed during exposure is reduced.
, The minimum pulse oscillation number n required to achieve the above can be reduced, thereby improving the scanning speed (scan speed), thereby improving the throughput.

According to a twenty-eighth aspect of the present invention, there is provided a device manufacturing method including a photolithography step, wherein exposure is performed by using the exposure apparatus according to the twenty-fourth aspect in the photolithography step. According to this, exposure is performed by the above-described exposure apparatus using an energy beam having a wavelength of 300 nm or less, and at this time, based on information measured using a sensor having a light detection unit made of the GaN-based crystal, An image of the mask pattern is formed thereon at a predetermined resolution and depth of focus. Therefore, in the device manufacturing method according to the present invention, for example, the resolution is 0.25 μm
A circuit device formed by exposing a line width of up to 0.05 μm can be manufactured with a high yield.

[0059]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG.

FIG. 1 shows a schematic configuration of an exposure apparatus 10 according to one embodiment. The exposure apparatus 10 is a step-and-scan type scanning exposure apparatus.

The exposure apparatus 10 includes an illumination system including a light source 16 and an illumination optical system 12 as a light source device, a reticle stage RST for holding a reticle R as a mask illuminated by exposure light IL from the illumination system, and a reticle. R
A projection optical system PL for projecting the exposure light IL emitted from the substrate onto a wafer W as a substrate, an XY stage 14 on which a Z tilt stage 58 as a substrate stage for holding the wafer W is mounted, and a control system therefor. Have.

The light source 16 has a wavelength of 193 nm, for example.
An ArF excimer laser light source that outputs ultraviolet pulsed light (or a KrF excimer laser light source that outputs ultraviolet pulsed light having a wavelength of 248 nm) is used. The light source 16 is actually a clean room in which the chamber 11 in which the components of the illumination optical system 12 and the exposure apparatus main body including the reticle stage RST, the projection optical system PL, and the XY stage 14 are housed is installed. It is located in another service room with low cleanliness,
(Illumination optical system 12) is connected via a beam matching unit (not shown) and a relay optical system. In addition,
An F ₂ laser light source (output wavelength: 157 nm) or another pulse light source may be used as the light source.

FIG. 2 shows the inside of the light source 16 together with the main controller 50. The light source 16 includes a laser resonator 16a, a beam splitter 16b, a beam monitor 16c as a first optical sensor, and an energy controller 16d.
And a high voltage power supply 16e.

The laser beam LB emitted in a pulse form from the laser resonator 16a enters a beam splitter 16b having a high transmittance and a small reflectance, and the laser beam LB transmitted through the beam splitter 16b is emitted to the outside. You. The laser beam LB reflected by the beam splitter 16b is incident on a beam monitor 16c as a first optical sensor having a detector made of a GaN-based crystal, and a photoelectric conversion signal from the beam monitor 16c is used as a peak hold (not shown). It is supplied to the energy controller 16d as an output ES via a circuit. The beam monitor 16
The configuration and the like of the optical sensor constituting c are features of the present invention, and will be described in detail later.

At the time of normal light emission, the energy controller 16d sets the output ES of the beam monitor 16c to a value corresponding to the target value of energy per pulse in the control information TS supplied from the main controller 50. The power supply voltage of the high-voltage power supply 16e is feedback-controlled. The unit of the energy control amount corresponding to the output ES of the beam monitor 16c is [mJ / pulse]. The energy controller 16d sets the power supply voltage in the high-voltage power supply 16e based on the control information TS from the main control device 50, and thereby sets the laser beam L
The pulse energy of B is set near a predetermined value. In this case, the average value of the energy per pulse of the light source 16 is normally stabilized at a predetermined center energy E ₀ , but the average value of the energy is in a predetermined variable range above and below the center energy E ₀ ( (For example, about ± 10%). In the present embodiment, fine modulation of pulse energy is performed in the variable range. The energy controller 16d also changes the oscillation frequency by controlling the energy supplied to the laser resonator 16a via the high-voltage power supply 16e.

The beam splitter 16 in the light source 16
A shutter 16f for blocking the laser beam LB in accordance with control information from the main controller 50 is also provided outside b.

Here, the beam monitor 16c of the present embodiment is used.
An example of a GaN-based semiconductor light-receiving element constituting an optical sensor used as a device will be described with respect to its structure, detection principle, and the like.

FIG. 3A is a plan view of the GaN-based semiconductor light-receiving element 17, and FIG. 3B is a plan view of FIG.
The sectional views taken along the line B are shown.

This GaN-based semiconductor light receiving element 17 is similar to that shown in FIG.
As shown in (B), a crystal substrate B1, a light-receiving layer 1 made of a first conductivity type GaN-based semiconductor laminated on the crystal substrate B1 via a buffer layer B2, and the light-receiving layer 1 And a Schottky electrode Q1 and an ohmic electrode Q2 provided on the light receiving surface 1a, which is a surface on one side (the upper side in FIG. 3B). Symbol L in FIG. 3B indicates light to be detected.

The crystal substrate B1 only needs to be capable of growing a GaN-based semiconductor crystal, and can be made of sapphire, quartz, SiC
And GaN-based crystals. If the crystal substrate is an insulator, a sapphire C-plane or A-plane, particularly a C-plane sapphire substrate is preferable. If the crystal substrate requires conductivity, a 6H-SiC substrate or a GaN-based crystal is preferable.

The buffer layer B2 is provided to alleviate the difference in the lattice constant and the coefficient of thermal expansion between the crystal substrate B1 (for example, a sapphire crystal plate) and the GaN-based crystal. Become. Buffer layer B
2 may not necessarily be provided, or a GaN-based crystal thin film may be provided between the buffer layer B2 and the light receiving layer 1.

The conductivity type of the GaN-based semiconductor used for the light-receiving layer 1 may be the first conductivity type (that is, either p-type or n-type). In view of the above, it is preferable to use an n-type. In the following description, it is assumed that the light-receiving layer 1 uses an n-type GaN-based semiconductor.

The GaN-based semiconductor used for the light receiving layer 1 is as follows:
The value at the long wavelength end of the wavelength range of the light to be detected,
Its optimal composition is determined. For example, the blue region (48
0 nm) and shorter wavelengths, InGaN when targeting light in the short wavelength range of 400 nm or less even with ultraviolet light.
GaN and AlGaN are selected when only nGaN and 365 nm or less ultraviolet rays are targeted.

In this embodiment, an electrode having a comb shape as shown in FIG. 3A is used as the Schottky electrode Q1. In this case, in the light receiving surface 1a, a boundary line between a region covered with the Schottky electrode Q1 (hereinafter, referred to as “covered region”) and an exposed region (hereinafter, referred to as “exposed region”). , Ie, the total extension of the entire outline of the Schottky electrode Q1 is longer than the outer periphery of the light receiving surface 1a. The reason for this will be described later.

As is well known, a Schottky electrode refers to an electrode in which a potential barrier called a Schottky barrier is generated by a junction between a metal and a semiconductor, and examples of the electrode material include Au, Pt, and TiW. Can be Further, these materials may be used in combination.

The material of the ohmic electrode Q2 is as follows.
A1 / Ti, Au / Ti, Ti, and the like. Further, these materials may be used in combination. Also,
At the time of light detection, as will be described later, a voltage is applied so that the Schottky electrode Q1 side is reverse-biased. Therefore, even if the ohmic electrode Q2 side has a Schottky barrier, no significant problem occurs. This means that even if both electrodes are formed as Schottky electrodes, if a reverse bias voltage is applied to the electrode on the light receiving surface, the other electrode will be in a forward-biased state, and as a result, will be equivalent to an ohmic electrode. Means to work.

The principle of light detection of the GaN semiconductor light receiving element 17 will be briefly described. By applying a reverse bias voltage between the two electrodes Q1 and Q2, electrons can easily flow from the light receiving layer 1 to the Schottky electrode Q1. In addition, the flow of electrons generated by photoexcitation in the light receiving layer 1 is detected as a current.

The GaN semiconductor light receiving device 1 according to the present embodiment
The feature of No. 7 is that, as shown in FIG. 4, the depletion layer 1b is used noting just under the Schottky electrode Q1 but also extending a small amount around the electrode Q1 and utilizing it. It is in. Light L1 can also enter the portion of the depletion layer 1b that protrudes only a small amount around the electrode Q1 (hereinafter, referred to as "protrusion of the depletion layer") from the upper surface side of the electrode Q1. Further, the light L is located near the periphery of the electrode Q1 even immediately below the Schottky electrode Q1.
There is also light incident in an oblique direction as shown in FIG. Light entering the semiconductor also causes an interaction with the depletion layer 1b below the electrode Q1 due to diffraction.

In the present embodiment, the protruding portion of the depletion layer and the depletion layer portion immediately below the electrode Q1 are more secured, and are positively used for light reception detection. Therefore, as described above, the length of the boundary between the covering region and the exposed region is set to be longer than the outer circumference of the light receiving surface 1a. Thereby, the length of the boundary line becomes sufficiently long, and light emitted from the upper surface side of the electrode Q1 can be detected.

The shape of the Schottky electrode Q1 is shown in FIG.
In the case of a comb-shaped wiring pattern as shown in (A), the portion corresponding to the teeth of the comb has a stripe shape in which strip-shaped conductors are arranged in parallel. The width of the strip-shaped conductor corresponding to the teeth of the comb is 0.1 μm to 2000 μm, and the width of the gap between the conductors is 0.1 μm to 2000 μm. Preferably it is 1000 μm.

The shape of the Schottky electrode may be a wiring pattern formed by arbitrarily combining strip conductors other than the comb shape. For example, a pattern in which the strip-shaped conductor meanders like a rectangular wave, a pattern in which the strip-shaped conductor intersects in a grid pattern, and the like are given. The width of the band of the band-shaped conductor is preferably 0.1 μm to 2000 μm as in the case of the comb shape. Further, in addition to the above-described pattern, an embodiment having an opening of an arbitrary shape as an exposed region may be adopted. As the number of openings increases, the total length of the boundary between the electrode region and the exposed region increases.

Next, a specific embodiment of the GaN-based semiconductor light receiving element 17 will be described. In the semiconductor light receiving element 17 according to this embodiment, Ga on the C-plane sapphire substrate B1
N-type AlGaN layer (light receiving layer) via N buffer layer B2
1 was grown. The AlGaN layer has a composition ratio such that the band gap is about 3.67 eV, the thickness is 3 μm, the outer shape of the light receiving surface 1a is a square of 5 mm × 5 mm, and the carrier concentration is 1 × 10 ¹⁷ cm ⁻³ .

5 mm × 48 of the square of the light receiving surface 1 a
A Schottky electrode Q1 having a comb-shaped pattern was provided in a square region of 40 μm, and a square ohmic electrode Q2 was provided in the remaining region to face each other. The Schottky electrode Q1 was made of Au having a thickness of 500 nm and had a comb-shaped pattern with 500 teeth. At this time, the total length of the boundary line between the covering region and the exposed region was about 230 times the outer circumference of the light receiving surface. The ohmic electrode Q2 was formed on the light receiving surface in the order of a Ti layer and an A1 layer.

With a reverse bias of 5 V applied between the two electrodes Q1 and Q2 of the GaN-based semiconductor light-receiving element 17 manufactured as described above, light of various wavelengths from above and perpendicular to the light-receiving surface 1a. Was irradiated, and the light-receiving performance was examined. As a result, it was found that the film was sensitive to ultraviolet rays of about 340 nm or less. In the wavelength range of 340 nm or less, the light absorption characteristic of AlGaN, which is a problem when light is incident from the substrate side as in the related art, directly contributes to the light receiving sensitivity in the present embodiment. It became a flat characteristic. In the wavelength region longer than 340 nm, since light was not absorbed, the temperature of the element rarely rose, and there was no sensitivity at all.

When the Schottky electrode and the ohmic electrode are provided as described above, for example, another n-type GaN-based crystal layer for providing the ohmic
Between the buffer layer B2 and another n-type G
An ohmic electrode may be provided on the upper surface of the aN-based crystal layer so as to surround the Schottky electrode. Alternatively, crystal substrate B
When 1 is a substrate made of a material exhibiting conductivity, an ohmic electrode may be provided on almost the entire lower surface of the crystal substrate.

The GaN-based semiconductor light receiving element 17 configured as described above is housed in a package, for example, as shown in FIG. The optical sensor 2 shown in FIG. 5 uses a so-called hermetic seal container, and has a structure in which a GaN-based semiconductor light receiving element 17 is mounted on a stem P1 provided with a terminal 3 and sealed with a cap P2. Has become. Cap P2
Is provided with a window 4 for allowing external light to enter the internal GaN-based semiconductor light-receiving element 17 as in a known light-receiving element package. Inside the window 4, a window plate 5 made of fluorite or synthetic quartz for transmitting light to be received is attached.
A short wavelength transmission filter F that transmits only light having a wavelength shorter than 0 nm is provided. In this way, light other than the light to be received can be cut. However, when used in an exposure apparatus, the filter F need not always be provided because it is usually used under the condition that only light to be received is irradiated.

According to the optical sensor 2 shown in FIG.
The ArF excimer laser light L of 3 nm passes through the window plate 5 and the filter F, and is transmitted by the GaN-based semiconductor light receiving element 17.
It is detected with good sensitivity.

Returning to FIG. 1, the illumination optical system 12 includes a beam shaping optical system 18, an energy rough adjuster 20, a fly-eye lens 22 as an optical integrator (homogenizer), an illumination system aperture stop plate 24, a beam splitter 26, First relay lens 28A, second relay lens 28
B, a fixed reticle blind 30A, a movable reticle blind 30B, a mirror M for bending the optical path, a condenser lens 32, and the like.

The beam shaping optical system 18 includes the chamber 1
1 (to be precise, a lens barrel of the illumination optical system 12 or one end surface of a housing for housing the same) is connected to a beam matching unit (or a relay optical system) (not shown) through a light transmission window 13 provided in the illumination optical system 12. I have. The beam shaping optical system 18
The sectional shape of the laser beam LB pulsed in step 6 is
The laser beam LB is shaped so as to efficiently enter a fly-eye lens 22 provided behind the optical path of the laser beam LB.
For example, it is composed of a cylinder lens, a beam expander (both not shown), and the like.

The energy rough adjuster 20 is disposed on the optical path of the laser beam LB behind the beam shaping optical system 18.
Here, the transmittance around the rotating plate 34 (= 1−the extinction ratio)
(For example, two ND filters 36A and 36D are shown in FIG. 1), and its rotating plate 34 is rotated by a driving motor 38 The transmittance for the incident laser beam LB can be switched from 100% in geometric progression in a plurality of steps. Drive motor 38
Is controlled by a main controller 50 described later. Note that a rotary plate similar to the rotary plate 34 may be arranged in two stages so that the transmittance can be more finely adjusted by a combination of two sets of ND filters.

The fly-eye lens 22 is arranged on the optical path of the laser beam LB emitted from the energy rough adjuster 20, and is a surface light source composed of a number of light source images for illuminating the reticle R with a uniform illuminance distribution. Form a secondary light source. The laser beam emitted from the secondary light source is also referred to as “exposure light IL” in this specification.

In the vicinity of the exit surface of the fly-eye lens 22,
An illumination system aperture stop plate 24 made of a disk-shaped member is arranged. This illumination system aperture stop plate 24 is provided at equal angular intervals,
For example, an aperture stop composed of a normal circular aperture, an aperture stop composed of small circular apertures for reducing the σ value which is a coherence factor, a ring-shaped aperture stop for annular illumination, and a plurality of apertures for a modified light source method. A modified aperture stop which is eccentrically arranged (only two types of aperture stops are shown in FIG. 1) and the like are arranged. The illumination system aperture stop plate 24 is configured to be rotated by a driving device 40 such as a motor controlled by a main controller 50, whereby any one of the aperture stops is selectively placed on the optical path of the exposure light IL. Is set to

Exposure light IL emitted from illumination system aperture stop plate 24
A beam splitter 26 having a small reflectance and a large transmittance is disposed on the optical path of the first relay lens 28A, and the first relay lens 28A and the second relay A relay optical system including a lens 28B is provided.

The fixed reticle blind 30A is arranged on a plane slightly defocused from a plane conjugate to the pattern plane of the reticle R, and has a rectangular opening defining an illumination area 42R on the reticle R. Further, a movable reticle blind 30B having an opening whose position and width in the scanning direction are variable near the fixed reticle blind 30A.
Is arranged, and at the start and end of the scanning exposure, the illumination area 42R is further restricted via the movable reticle blind 30B, so that exposure of an unnecessary portion is prevented. In the present embodiment, the movable reticle blind 30B is also used for setting an illumination area when detecting an aerial image by aerial image measurement described later.

A bending mirror M for reflecting the exposure light IL passing through the second relay lens 28B toward the reticle R is disposed on the optical path of the exposure light IL behind the second relay lens 28B constituting the relay optical system. And this mirror M
A condenser lens 32 is arranged on the optical path of the rear exposure light IL.

Further, an integrator sensor 46 as a second and a third optical sensor and a reflected light monitor 47 are provided on one of the optical paths which are vertically bent by the beam splitter 26 in the illumination optical system 12 and on the other optical path. Each is arranged. In the present embodiment, as the integrator sensor 46 and the reflected light monitor 47, the optical sensor 2 having the above-described GaN-based semiconductor light receiving element 17 is used.
These integrator sensor 46 and reflected light monitor 47
Has good sensitivity in the deep ultraviolet region and the vacuum ultraviolet region, and has a light source 1
6 has a high response frequency to detect the pulsed light emission.

The operation of the illumination system 12 configured as described above will be briefly described. The laser beam LB pulse-emitted from the light source 16 enters a beam shaping optical system 18 where a rear fly-eye lens is provided. After its cross-sectional shape is shaped so as to be efficiently incident on the energy 22, the light is incident on the energy rough adjuster 20. The laser beam LB transmitted through any of the ND filters of the energy rough adjuster 20
Enter the fly-eye lens 22. As a result, a secondary light source is formed on the exit-side focal plane of the fly-eye lens 22 (pupil plane of the illumination optical system 12). The exposure light IL emitted from the secondary light source passes through one of the aperture stops on the illumination system aperture stop plate 24, and then reaches a beam splitter 26 having a large transmittance and a small reflectance. The exposure light IL transmitted through the beam splitter 26 is transmitted to a first relay lens 28
After passing through the rectangular opening of the fixed reticle blind 30A and the movable reticle blind 30B via A, the second
After the optical path is bent vertically downward by the mirror M after passing through the relay lens 28B, the rectangular illumination area 42R on the reticle R held on the reticle stage RST is illuminated with a uniform illuminance distribution via the condenser lens 32. I do.

On the other hand, the exposure light IL reflected by the beam splitter 26 is received by an integrator sensor 46 via a condenser lens 44, and a photoelectric conversion signal of the integrator sensor 46 is converted to a peak hold circuit (not shown) and an A / D converter.
It is supplied to the main controller 50 as an output DS (digit / pulse) via a converter. The correlation coefficient between the output DS of the integrator sensor 46 and the illuminance (exposure amount) of the exposure light IL on the surface of the wafer W is obtained in advance as described later, and is provided in the memory provided in the main controller 50. 51.

The illuminated area 42R on the reticle R illuminates the luminous flux reflected by the pattern surface of the reticle (the lower surface in FIG. 1). The light is reflected by the beam splitter 26 and received by a reflected light monitor 47 via a condenser lens 48. When the Z tilt stage 58 is below the projection optical system PL, the exposure light IL transmitted through the pattern surface of the reticle is applied to the projection optical system PL and the surface of the wafer W (or the surface of a reference mark plate FM described later). The reflected light flux passes through the projection optical system PL, the reticle R, the condenser lens 32, and the relay optical system sequentially in the opposite direction to the front, is reflected by the beam splitter 26, and is reflected by the condensing lens 48. The light is received by the monitor 47. Each optical element disposed between the beam splitter 26 and the wafer W has an anti-reflection film formed on the surface thereof, but the exposure light IL is slightly reflected on the surface, and the reflected light is also reflected light. The light is received by the monitor 47. The photoelectric conversion signal of the reflected light monitor 47 is supplied to the main controller 50 via a peak hold circuit and an A / D converter (not shown). In this embodiment, the reflected light monitor 47 is mainly used for measuring the reflectance of the wafer W and the like. This will be described later. The reflected light monitor 47 is connected to the reticle R
May be used at the time of preliminary measurement of the transmittance.

A reticle R is mounted on the reticle stage RST, and is held by suction via a vacuum chuck (not shown). The reticle stage RST is finely drivable in a horizontal plane (XY plane), and is scanned by a reticle stage driving unit 49 in a predetermined stroke range in a scanning direction (here, the Y direction which is the horizontal direction of the paper of FIG. 1). It has become so. The position and the rotation amount of the reticle stage RST during the scanning are measured by an external laser interferometer 54R via a movable mirror 52R fixed on the reticle stage RST, and the measured value of the laser interferometer 54R is used as a main controller. 50.

The material used for the reticle R must be properly used depending on the light source used. That is, Kr
When an F excimer laser light source or an ArF excimer laser light source is used as a light source, synthetic quartz can be used.
_{In the} case where a _two- laser light source is used, it is necessary to use fluorite, synthetic quartz doped with fluorine, or quartz.

The projection optical system PL is, for example, a double-sided telecentric reduction system, and includes a plurality of lens elements 70a, 70b,... Having a common optical axis in the Z-axis direction. As the projection optical system PL, one having a projection magnification β of, for example, １ ／, 、, 、, or the like is used. Therefore, as described above, when the illumination area 42R on the reticle R is illuminated by the exposure light IL, the image formed by reducing the pattern formed on the reticle R by the projection optical system PL at the projection magnification β is applied to the surface. Is projected onto a slit-shaped exposure region 42W on a wafer W on which a resist (photosensitive agent) is applied and transferred.

In this embodiment, among the above lens elements, a plurality of lens elements can be independently moved. For example, the uppermost lens element 70a closest to the reticle stage RST is held by a ring-shaped support member 72.
Telescopic drive elements, for example, piezo elements 74a, 74
b, 74c (the drive element 74c on the far side of the drawing is not shown) is supported at three points and is connected to the lens barrel 76. The drive elements 74a, 74b, and 74c allow the three peripheral points of the lens element 70a to be independently moved in the optical axis AX direction of the projection optical system PL. That is, the lens element 70a can be translated along the optical axis AX according to the displacement of the driving elements 74a, 74b, 74c, and can be arbitrarily inclined with respect to a plane perpendicular to the optical axis AX. . Then, these drive elements 74a, 74b, 74
The voltage applied to c is controlled by the imaging characteristic correction controller 78 based on a command from the main controller 50, whereby the displacement of the driving elements 74a, 74b, 74c is controlled. In FIG. 1, the optical axis AX of the projection optical system PL refers to the optical axis of the lens element 70b fixed to the lens barrel 76 and other lens elements (not shown).

In the present embodiment, the relationship between the vertical amount of the lens element 70a and the change amount of the magnification (or distortion) is obtained in advance by experiments, and this is stored in the memory inside the main controller 50. The vertical amount of the lens element 70a is calculated from the magnification (or distortion) corrected by the main controller 50 at the time of correction, and an instruction is given to the imaging characteristic correction controller 48 to drive the drive elements 74a, 7a.
By driving the 4b and 74c, magnification (or distortion) correction is performed. The relationship between the vertical amount of the lens element 70a and the amount of change in magnification or the like may use an optically calculated value. In this case, an experiment is performed to determine the relationship between the vertical amount of the lens element 70a and the amount of change in magnification. Process can be omitted.

As described above, the lens element 70a closest to the reticle R is movable. However, this lens element 70a has a larger influence on the magnification and distortion characteristics than the other lens elements and can be easily controlled. As long as one of them is selected and satisfies the same condition, any lens element may be configured to be movable for adjusting the lens interval instead of the lens element 70a. Note that the lens element 7
By moving at least one lens element other than 0a, other optical characteristics such as curvature of field, astigmatism, coma, or spherical aberration can be adjusted.
In addition, by providing a sealed chamber between specific lens elements near the center of the projection optical system PL in the optical axis direction, and adjusting the pressure of gas in the sealed chamber by a pressure adjusting mechanism such as a bellows pump, An imaging characteristic correction mechanism for adjusting the magnification of the projection optical system PL may be provided. Alternatively, for example, an aspherical lens may be used as a part of the lens elements constituting the projection optical system PL, and the lens may be rotated. May be. In this case, so-called rhombic distortion can be corrected. Alternatively, the projection optical system P
A parallel plane plate may be provided in L, and the imaging characteristic correction mechanism may be configured by a mechanism that tilts or rotates it.

When KrF excimer laser light or ArF excimer laser light is used as the exposure light IL, synthetic quartz, fluorite or the like is used as each lens element (and the above-mentioned parallel plane plate) constituting the projection optical system PL. it can be used, in the case of using the F ₂ laser light, the material of the lens and the like used in the projection optical system PL, all fluorite is used.

The XY stage 14 is two-dimensionally driven by a wafer stage driving section 56 in the Y direction, which is the scanning direction, and the X direction, which is orthogonal to the scanning direction (the direction perpendicular to the plane of FIG. 1). The wafer holder 61 is mounted on a Z tilt stage 58 mounted on the XY stage 14.
The wafer W is held by vacuum suction or the like via an illustration (not shown in FIG. 1, see FIG. 6). Z tilt stage 58
Has a function of adjusting the position (focus position) of the wafer W in the Z direction (focus position) by, for example, three actuators (piezo elements or voice coil motors) and adjusting the tilt angle of the wafer W with respect to the XY plane. Also, X
The position of the Y stage 14 is controlled by an external laser interferometer 54 via a movable mirror 52W fixed on a Z tilt stage 58.
W, and the measured value of the laser interferometer 54W is supplied to the main controller 50.

Here, the moving mirror is actually an X moving mirror 54 having a reflecting surface perpendicular to the X axis, as shown in FIG.
There is a Wx and a Y moving mirror 54Wy having a reflecting surface perpendicular to the Y axis, and correspondingly, the laser interferometer is also used for the X axis position measurement, the Y axis position measurement, and the rotation measurement (the amount of yawing,
(Including a pitching amount and a rolling amount) are provided, respectively, and in FIG. 1, these are representatively shown as a moving mirror 52W and a laser interferometer 54W.

On the Z tilt stage 58, a light receiving surface (or a surface to be irradiated) having the same height as the exposure surface of the wafer W is provided near the wafer W, and the exposure light having passed through the projection optical system PL is provided. An irradiation amount sensor 59 for detecting the amount of IL light is disposed. In the present embodiment, three types of irradiation amount sensors, an irradiation amount monitor, an illuminance unevenness sensor, and an aerial image measuring device, are provided, but these are representatively shown as an irradiation amount sensor 59 in FIG. I have.

FIG. 6 is a schematic plan view of the Z tilt stage 58. As shown in FIG.
Among the four corners of the Z tilt stage 58, at the first corner at the end in the + Y direction and at the end in the -X direction, the irradiation amount monitor 59A and the unevenness sensor 59B are arranged side by side in the Y direction. Further, an aerial image measuring instrument 59C is arranged at a second corner of the + Y direction end and the + X direction end of the Z tilt stage 58.

The irradiation amount monitor 59A has a rectangular housing in a plan view extending in the X direction, which is slightly larger than the exposure area 42W. 59d are formed. The opening 59d is actually formed by removing a part of the light shielding film formed on the upper surface of the light receiving glass made of synthetic quartz or the like forming the ceiling surface of the housing. The irradiation amount monitor 59A is used for measuring the intensity of the exposure light IL applied to the exposure area 42W.

The unevenness sensor 59B has a housing having a substantially square shape in plan view, and a pinhole-shaped opening 59e is formed in the center of the housing. This opening 5
9e is actually formed by removing a part of the light shielding film formed on the upper surface of the light receiving glass made of synthetic quartz or the like forming the ceiling surface of the housing. Z tilt stage 5
Driving 8 in the XY two-dimensional directions via the XY stage 14 is used to measure the illuminance unevenness in the exposure area 42W, that is, the distribution of the intensity of the exposure light IL at each point in the exposure area 42W. In the present embodiment, the unevenness sensor 49B is also used for measuring the transmittance of the projection optical system PL, as described later.

The aerial image measuring instrument 59C has a substantially square housing in plan view, and a part of a reflection film formed on the upper surface of a light-receiving glass made of synthetic quartz or the like forming the ceiling surface of the housing has: A rectangular opening 59f is formed. The aerial image measuring device 59C is used for measuring the imaging characteristics of the projection optical system PL. The method of measuring the imaging characteristics will be described later.

Next, the configuration of the irradiation sensor will be described by taking the aerial image measuring instrument 59C as a representative of the three irradiation sensors. FIG. 7A shows this aerial image measuring device 5.
The vicinity of the Z tilt stage 58 of FIG. 1 including 9C is shown in an enlarged manner. In FIG. 7A, a projecting portion 58 having an open top is provided on the upper surface of one end of the Z tilt stage 58.
The light receiving glass 82 is fitted so as to close the opening of the protruding portion 58a. On the upper surface of the light-receiving glass 82, a reflection film 83 also serving as a light-shielding film, the surface of which is an irradiation surface, is formed. A substantially square opening (opening pattern) 59f as shown is formed. In FIG. 7B, a hatched portion (shaded portion) indicates a reflection surface (a surface to be irradiated) made of a reflection film. The reflecting surface also has a role of a reference reflecting surface when the focus sensor is to be described later in this embodiment.

As shown in FIG. 7A, lenses 84 and 8 are provided inside the Z tilt stage 58 below the opening 59f.
6 and a relay optical system (84,
86), a light receiving optical system including a bending mirror 88 that bends an optical path of an illumination light beam (image light beam) relayed by a predetermined optical path length, and the optical sensor 2 having the GaN semiconductor light receiving element 17 described above are arranged. .

According to the aerial image measuring device 59C, the projection optical system P of the measurement pattern formed on the reticle R described later is used.
At the time of detecting the projected image via L, the exposure light IL transmitted through the projection optical system PL illuminates the light receiving glass 82, and the exposure light IL transmitted through the opening 59f on the light receiving glass 82 is used as the light receiving optical element. GaN-based semiconductor light-receiving element 17 constituting optical sensor 2
At 7, photoelectric conversion is performed, and a light amount signal P corresponding to the amount of received light is output to the main controller 50.

The optical sensor 2 does not necessarily need to be provided inside the Z-tilt stage 58. The optical sensor 2 is arranged outside the Z-tilt stage 58, and the illumination light beam relayed by the relay optical system is used as an optical fiber or the like. Of course, the light sensor 2 may be led to the optical sensor 2 via

The structures of the irradiation amount monitor 59A and the unevenness sensor 59B are the same as those of the aerial image measuring device 59C except for the shape of the opening (opening pattern). The irradiation amount monitor 59A and the unevenness sensor 59B are described above. GaN
A light amount signal corresponding to the amount of light received by the system semiconductor light receiving element 17 is supplied to the main controller 50.

Returning to FIG. 1, on the Z tilt stage 58, there is provided a reference mark plate FM used for performing reticle alignment described later. The surface of the reference mark plate FM has substantially the same height as the surface of the wafer W. In practice, as shown in the plan view of FIG.
It is arranged at a third corner on the −X direction end and the −Y direction end on the Z tilt stage 58. Reference marks such as a reticle alignment reference mark and a baseline measurement reference mark are formed on the surface of the reference mark plate FM (this will be described later).

Although not shown in FIG. 1 to avoid complicating the drawing, the exposure apparatus 10 includes a reticle alignment system for performing the reticle alignment. Here, referring to FIG. 8 and FIG.
Configuration of reticle alignment system 100, alignment mark (reticle mark) formed on reticle R, and corresponding reference mark, and reticle R using them
An example of the alignment operation will be described.

FIG. 8 is a schematic side view of the condenser lens 32, the reticle R, the projection optical system PL, the Z tilt stage 58, the XY stage 14 and the like in FIG. 1 viewed in the + Y direction. However, reticle stage RST is not shown.

In FIG. 8, four pairs of reticle marks each formed of, for example, a cross-shaped two-dimensional mark are formed so as to sandwich the pattern area of the pattern surface of reticle R in the X direction. On the surface of the reference mark plate FM on the Z tilt stage 58, four pairs of reference marks are formed in an array in which the four pairs of reticle marks are reduced by the projection magnification.

FIG. 9 is an enlarged plan view showing a state where a part of the projection image RP of the reticle R and the reference mark plate FM in FIG. In FIG. 9, a first pair of reference marks 114A and 114E and a second pair of reference marks 11 are provided on the reference mark plate FM at predetermined intervals in the Y direction.
4B, 114F, a third pair of reference marks 114C, 1
14G, and a fourth pair of fiducial marks 114D, 114
H is formed. In FIG. 9, reticle R
The image PAP of the pattern area is projected onto the center of the projected image RP of the first pair of reticle mark images 113AP, 113EP, and the second pair at both sides of this image PAP at predetermined intervals in the Y direction.
A pair of reticle mark images 113BP and 113FP, a third pair of reticle mark images 113CP and 113GP,
And a fourth pair of reticle mark images 113DP, 113
HP is projected. Note that, in FIG. 9, for simplicity of description, the above is performed as described above. However, in the case of a scanning exposure apparatus such as the present embodiment, in fact, all reticle mark images are projected simultaneously, Needless to say, the entire pattern area is not projected at once. FIG.
In FIG. 9, a pair of reference marks 114D and 114H and reticle marks 113D and 113H corresponding to the reticle mark images 113DP and 113HP appear.

When performing alignment of reticle R, first, main controller 50 drives reticle stage RST and XY stage 14 via reticle stage driving section 49 and wafer stage driving section 56, as shown in FIG. The reference marks 114D and 114H on the reference mark plate FM are set in the rectangular exposure area 42W, and the reticle mark image 113 is set on the reference marks 114D and 114H.
The relative position between reticle R and Z tilt stage 58 is set such that DP and 113HP substantially overlap. In this state, as shown in FIG. 8, a pair of half prisms 10 of the reticle alignment system 100
1R and 101L are inserted by a driving device (not shown).
During normal exposure, the half prisms 101R, 101R, 10R
1L is retracted outside the optical path.

Then, the illumination light ILR transmitted through the condenser lens 32 is transmitted through the half prism 101R and is applied to the reticle mark 113H on the reticle R. The illumination light reflected by the reticle mark 113H is applied to the half prism 101R. Return to Also, reticle mark 1
Illumination light ILR transmitted through the periphery of 13H is projected onto projection optical system P
L, the reference mark 114H on the reference mark plate FM is illuminated, and the reflected light from the reference mark 114H passes through the projection optical system PL and the reticle R to form the half prism 101R.
Return to Reticle mark 113H and reference mark 114
The reflected light from H is reflected by the half prism 101R, and then is applied to the reticle mark 11 on the imaging surface of the two-dimensional imaging device 104R via the relay lenses 102R and 103R.
An image of 3H and the reference mark 114H is formed. The imaging signal of the imaging element 104R is supplied to the main control device 50, and the main control device 50 processes the imaging signal and processes the reference mark 1
The amount of displacement of the projected image of the reticle mark 113H with respect to 14H in the X and Y directions is calculated. Similarly, the relay lens 102L is also provided on the half prism 101L side on which the other illumination light ILL transmitted through the condenser lens 32 is incident.
L, 103L and an image sensor 104L are provided, and an image signal of the image sensor 104L is also supplied to the main controller 50,
In the main controller 50, the reference mark 114 is obtained from the image signal.
X direction of the projected image of reticle mark 113D with respect to D,
The amount of displacement in the Y direction is calculated.

In this embodiment, the image pickup device 104R,
As the image pickup device 104L, a two-dimensional image pickup device including a light receiving unit including a large number of the above-described GaN-based semiconductor light receiving devices 17 is used.

FIG. 10 shows an example of the configuration of the image sensor 104R. As illustrated in FIG. 10, the image sensor 104 </ b> R sets the left-right direction on the paper as a row direction (horizontal direction),
The above-mentioned GaN-based semiconductor light-receiving elements 17 arranged in a matrix with the vertical direction of the paper as a column direction (vertical direction);
A switch element 301 provided for each GaN-based semiconductor light receiving element 17, a vertical signal line 303 provided in common for the GaN-based semiconductor light-receiving elements 17 arranged in the column direction, and a switch element 301 provided for each vertical signal line 303. Switch element 305
And an image signal output line 307 provided in common to all the GaN-based semiconductor light receiving elements 17 and connected to the image signal output terminal 313. Here, the wiring for the switch elements 301 is arranged so that the switch elements 301 corresponding to the GaN-based semiconductor light receiving elements 17 arranged in the row direction are simultaneously opened and closed. In FIG. 10,
The GaN-based semiconductor light receiving element 17 is represented by a diode symbol, and the switch elements 301 and 305 are represented by FET symbols. In FIG. 10, the GaN-based semiconductor light receiving element 1
7 is arranged in a matrix of 5 rows and 5 columns, the arrangement of the GaN-based semiconductor light receiving elements 17 is arbitrary, and the form of the arrangement may be determined according to a desired imaging resolution and imaging range. it can. Further, the image sensor 104R further includes a vertical shift register 309 for controlling opening and closing of the switch element 301 and a horizontal shift register 311 for controlling opening and closing of the switch element 305.

In the image sensor 104R, the vertical shift register 309 operates in synchronization with the supplied vertical clock signal.
The signal output terminals of the GaN-based semiconductor light receiving elements 17 arranged in each row are connected to each GaN-based semiconductor light receiving element 17 by sequentially selecting the first row and setting the switch element 301 corresponding to the selected row to a closed state (ON). It is connected to the vertical signal line 303 corresponding to the system semiconductor light receiving element 17. Each time one row is selected by the vertical shift register 309, the horizontal shift register 311 sequentially selects the first column to the last column in synchronization with the supplied horizontal clock signal, and selects the selected column. , The signal output terminals of the GaN-based semiconductor light receiving elements 17 arranged in the selected row are sequentially connected to the image signal output lines.

As described above, the signal output terminal of each GaN-based semiconductor light receiving element 17 is sequentially connected to the image signal output terminal 313, so that each GaN-based semiconductor light-receiving element 1 is connected.
The signal charges photoelectrically converted and accumulated at 7 are guided to an externally provided low-noise amplifier via the image signal output terminal 313 at the same timing as the signal obtained using the CCD element.

In FIG. 10, an example in which an output signal similar to a normal image signal is obtained has been described. However, a method of randomly accessing signal charges of each of the GaN-based semiconductor light receiving elements 17 is adopted, and an image pickup element 104R is used. Can of course be configured.

The image sensor 104L has the same configuration as the image sensor 104R described above.

In this embodiment, the half prism 101
R, 101L, relay lenses 102R, 103R, relay lenses 102L, 103L, and image sensor 104R,
A reticle alignment system 100 as a mask alignment system is constituted by 104L.

The reticle alignment of the present embodiment is used to measure the amount of positional deviation with high accuracy when the reticle is replaced or when the reticle is displaced due to thermal deformation or the like due to irradiation of illumination light. "Fine mode"
And a “quick mode” for confirming the position of the reticle at the time of wafer exchange or before and after wafer exchange. The alignment in the quick mode is also called “interval alignment”.

In the former fine mode, after the positional displacement of the image of the pair of reticle marks 113D and 113H is measured in the state shown in FIG. 8, the main controller 50 controls the reticle stage driving section 49 and the wafer stage driving section. By moving the reference mark plate FM and the reticle R in the Y direction in synchronization with the projection magnification ratio via the respective 56, the other three pairs of reference marks 114C, 114G to 114A,
Reticle mark images 113CP and 113 for 114E
The positional deviation amounts of GP to 113AP and 113EP are measured. Then, main controller 50 determines the offset, rotation angle, distortion, and scanning direction of the positional deviation of the projected image of reticle R with respect to reference mark plate FM, and thus Z tilt stage 58, from the positional deviation of these four pairs of reticle marks. Of the reticle R at the time of scanning exposure so as to minimize the amount of positional deviation of the reticle R, and project the image via the imaging characteristic correction controller 78 so as to minimize the distortion. Optical system PL
And the reticle R during scanning exposure.
Is corrected in the scanning direction.

On the other hand, in the latter quick mode, as shown in FIG. 8, a pair of fiducial marks 114D, 114H
Only the two-dimensional displacement of the images of the reticle marks 113D and 113H with respect to is measured, and only the offset and rotation angle of the reticle R obtained from the measurement result are corrected. By using this quick mode, it is possible to correct the positional deviation amount of the reticle R in a short time such as when exchanging a wafer, so that sufficient alignment performance can be maintained without lowering the throughput of the exposure process. it can. These alignment operations are disclosed in detail in Japanese Patent Application Laid-Open No. 7-176468.

A detection signal (image signal) of the projected image of the reference mark obtained as a result of the alignment of the reticle.
It is also possible to obtain a focus offset and a leveling offset (the focal position of the projection optical system PL, the image plane inclination, and the like) based on the contrast information included in.

In the present embodiment, at the time of the reticle alignment described above, the main controller 50 also measures the baseline amount of the wafer-side off-axis alignment sensor (not shown) provided on the side surface of the projection optical system PL. Done. That is, as shown in FIG. 9, the reference mark Wm for baseline measurement is provided on the reference mark plate FM in a predetermined positional relationship with respect to the reference marks 114D, 114H and the like.
Are formed. When measuring the amount of displacement of the reticle mark via the reticle alignment system 100, the reference mark Wm is detected via the alignment sensor on the wafer side.
By measuring the amount of displacement of the alignment sensor with respect to the detection center of the alignment sensor, the baseline amount of the alignment sensor, that is, the relative positional relationship between the reticle projection position and the alignment sensor is measured.

Further, as shown in FIG. 1, the exposure apparatus 10 of the present embodiment has a light source 16 whose on / off is controlled by the main controller 50, and a large number of light sources 16 are directed toward the image forming plane of the projection optical system PL. An irradiation optical system 60a for irradiating an imaging light beam for forming an image of the pinhole or the slit from an oblique direction with respect to the optical axis AX, and receives the reflected light beam of the imaging light beam on the surface of the wafer W. An oblique incident light type multi-point focal position detection system (focus sensor) including the light receiving optical system 60b is provided. The main controller 50 controls the inclination of the reflected light flux of the parallel plate (not shown) in the light receiving optical system 60b with respect to the optical axis, thereby offsetting the focus detection system (60a, 60b) in accordance with the focus fluctuation of the projection optical system PL. To perform the calibration. As a result, the image plane of the projection optical system PL and the surface of the wafer W coincide with each other within the range (width) of the depth of focus in the above-described exposure area 42W. The detailed configuration of the multipoint focus position detection system (focus sensor) similar to that of the present embodiment is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-283403.

At the time of scanning exposure or the like, the main controller 50 controls the Z tilt stage 58 so that the defocus becomes zero based on a defocus signal (defocus signal) from the light receiving optical system 60b, for example, an S-curve signal. By controlling the Z position via a drive system (not shown), auto focus (auto focus) and auto leveling are executed.

The reason why a parallel flat plate is provided in the light receiving optical system 60b to give an offset to the focus detection systems (60a, 60b) is that, for example, the focus is adjusted by moving the lens element 70a up and down for magnification correction. Also, since the projection optical system PL absorbs the exposure light IL, the imaging characteristics change and the position of the imaging surface fluctuates. In such a case, an offset is given to the focus detection system, and the focus detection system This is because it is necessary to match the in-focus position with the position of the imaging plane of the projection optical system PL. For this reason, in the present embodiment, the relationship between the vertical amount of the lens element 70a and the focus change amount is also obtained by an experiment in advance and stored in the memory inside the main control device 50. The lens element 70
A calculated value may be used for the relationship between the vertical amount of a and the focus change amount. Further, the auto-leveling may not be performed in the scanning direction but may be performed only in the non-scanning direction orthogonal to the scanning direction.

The control system is mainly constituted by a main control device 50 as a control device in FIG. Main controller 50
Is configured to include a so-called microcomputer (or workstation) composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., so that the exposure operation can be performed accurately. For example, synchronous scanning of the reticle R and the wafer W, stepping of the wafer W, exposure timing, and the like are controlled. Further, in the present embodiment, the main controller 50 controls the exposure amount at the time of scanning exposure as described later,
The amount of change in the imaging characteristics of the projection optical system PL is calculated by calculation based on the detection result of the projection image (aerial image) of the measurement mark (mark pattern) described later, and the imaging characteristics are calculated based on the calculation result. The projection optical system P via the correction controller 78
In addition to adjusting the imaging characteristics of L, the overall control of the entire apparatus is performed.

More specifically, the main controller 50 synchronizes with the scanning of the reticle R via the reticle stage RST in the + Y direction (or the −Y direction) at the speed Vr = V, for example, during scanning exposure. , The wafer W is moved in the −Y direction (or + Y direction) with respect to the exposure area 42W via the XY stage 14.
Laser interferometer 54 so that scanning is performed at a speed Vw = β · V (β is a projection magnification from reticle R to wafer W).
The positions and speeds of the reticle stage RST and the XY stage 14 are controlled via the reticle stage driving unit 49 and the wafer stage driving unit 56 based on the measured values of R and 54W, respectively. Further, at the time of stepping, main controller 50 controls XY stage 14 via wafer stage driving unit 56 based on the measurement value of laser interferometer 54W.
Control the position of.

Next, the calibration (calibration) of the integrator sensor 46 by the reference illuminometer as a premise of the exposure amount control will be described. The reason why such calibration is required is to match the exposure amount between the exposure apparatuses, that is, between the exposure machines. That is, by using a reference illuminometer common to a plurality of exposure apparatuses used in the same device manufacturing line, and calibrating an integrator sensor serving as a reference of the illuminance of each exposure apparatus, one exposure apparatus can be used. If the exposure amount is optimally set for a resist having a certain sensitivity, the optimal exposure amount can be set for a resist having the same sensitivity in a similar manner in another apparatus.

First, the reference illuminometer for calibration will be briefly described. This reference illuminometer is a type of irradiation sensor that detects the intensity of the exposure light IL on the image plane via the projection optical system PL. As shown in FIG. 11, the reference illuminometer 90 is separated into a sensor head section 90A and a main body data processing section (not shown), and these are connected by a cable 92. Since the reference illuminometer 90 needs to be used also for calibration of the integrator sensor of another unit (exposure apparatus), the sensor head unit 90 is advantageous for carrying.
A has a compact configuration. The main body data processing unit (not shown) is online with respect to the control system of the exposure apparatus 10, and is configured to be able to communicate data such as illuminance.

As described above, the sensor head 90A
Is separated from the main body data processing unit, so that the exposure apparatus 10 can be easily installed on the Z tilt stage 58. The sensor head portion 90A includes a fourth corner at the + X direction end and the −Y direction end of the Z tilt stage 58 (the remaining corners on which none of the sensors 59A to 59C and the reference mark plate FM in FIG. 6 are provided). Corner). For this reason, a positioning metal fitting (not shown) is provided at a predetermined position of the fourth corner portion, and the sensor head portion 90A can be fixed to the positioning metal fitting with screws or the like. I have.

Alternatively, a magnet may be provided on the back surface of the sensor head unit 90A, and the sensor head unit 90A may be attracted and fixed on the Z tilt stage 58 by the magnetic force of the magnet. In this case, the sensor head section 90A is positioned at a predetermined position only by aligning the sensor head section 90A with the positioning metal fitting, and is attracted and fixed by the magnetic force of the magnet. Further, in this case, not only is the installation of the sensor head unit 90A easy, but also if any load is applied, the sensor head unit 90A is immediately pulled out.
When the Y stage 14 moves, the cable 92
It is possible to prevent an accident such as damage to the inside of the exposure apparatus 10 due to the sensor head portion 90A jumping over and catching on a part of the exposure device 10 beforehand.

As shown in FIG. 11, the reference illuminometer 90
After the sensor head unit 90A is set at a predetermined position on the Z-tilt stage 58 by any of the above-described methods, as shown in FIG. Sensor head 9 of illuminometer 90
The XY stage 14 is moved so that the center position of 0A is located. In FIG. 12, a circle IF represents a projection optical system PL.
This shows the image field of.

In this state, main controller 50 executes simultaneous measurement of illuminance by reference illuminometer 90 and integrator sensor 46. When this measurement is completed, FIG.
As shown schematically, the position of the sensor head unit 90A is changed to the integrator sensor 46 inside the exposure area 42W.
The illuminance is simultaneously measured by the reference illuminometer 90 and the integrator sensor 46 while sequentially stepping in the XY two-dimensional directions within the area corresponding to the light receiving surface of the illuminator. In this manner, simultaneous measurement is performed by the integrator sensor 46 and the on-stage reference illuminometer 90 while moving the reference illuminometer 90 on the Z tilt stage 58 in a so-called raster scan state by m × n frames (see FIG. 13). . When the measurement is completed, main controller 50 obtains an average value of the measurement values of reference illuminometer 90 obtained by m × n measurements.

The above simultaneous measurement is performed for the entire illuminance adjustment range, and the average value of the measured values of the reference illuminometer 90 at each illuminance is determined.

When the simultaneous measurement by the integrator sensor 46 and the reference illuminometer 90 is completed over the entire illuminance adjustment range, the output value of the integrator sensor 46 corresponding to the average value of the measurement values of the reference illuminometer 90 at each illuminance is obtained. With the reference illuminometer 9 using the data.
The output of the integrator sensor 46 is calibrated against the output of 0. The specific sequence of calibration of the integrator sensor using such a reference illuminometer, which is based on the case where a mercury lamp is used as a light source, is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 10-83953. In the present embodiment, the sequence disclosed in the above publication can be partially modified and used.

By the way, in the reference illuminometer 90 of the present embodiment, the optical sensor having the GaN-based semiconductor light receiving element 17 described above is used for the sensor head 90A.

Next, a description will be given of a method of calculating a change in the imaging characteristic of the projection optical system PL due to absorption of illumination light.

First, a description will be given of a method of measuring the dose Q, which is a premise.

With the reticle R used for exposure mounted on the reticle stage RST, the movable reticle blind 30B and the illumination conditions (numerical aperture NA and coherence factor σ value) are set to the state at the time of exposure. For example, the main controller 50 adjusts an aperture stop (not shown) provided at the position of the pupil plane of the projection optical system PL and adjusts the numerical aperture N. A. Is set, and the illumination system aperture stop plate 2
4 is selectively set on the optical path.

Next, the main controller 50 drives the XY stage 14 so that the irradiation amount monitor 59A is located immediately below the projection optical system PL. Next, the main controller 50 controls the light source 16.
And reticle stage RST and XY stage 14
By capturing and at the same time at the output and a predetermined sampling interval the output I ₀ of the integrator sensor 46 of the radiation amount monitor 59A while moving synchronously in the same conditions as the actual exposure, and dose corresponding to the synchronous movement position (scan position) The value of Q ₀ and the corresponding output I ₀ of the integrator sensor 46 are stored in the memory 51. That is, the irradiation amount Q ₀ and the integrator sensor output I ₀ are equal to the reticle R
Are stored in the memory 51 as a function corresponding to the scanning position of

The above preparation work is performed by main controller 50.
Is executed prior to exposure. And at the time of actual exposure
The irradiation stored according to the scanning position of the reticle R
Quantity Q ₀And the output I of the integrator sensor 46₀And exposure
Output I of the integrator sensor 46 at the time₁On the basis of the,
Irradiation dose Q at that time₁Is calculated based on the following equation (1), and
Used to calculate bright light absorption.

Q ₁ = Q ₀ × I ₁ / I ₀ (1)

According to the equation (1), since the output of the integrator sensor 46 is used for the calculation, the irradiation amount can be calculated without error even when the power of the light source 16 fluctuates. Further, since the function corresponds to the scanning position of the reticle R, the irradiation amount can be accurately calculated even when the reticle pattern is unevenly distributed in the plane, for example.

In the above description, the output of the dose monitor 59A is taken under the illumination condition at the time of actual exposure as a preparatory work. However, for example, the signal may be saturated due to the characteristics of the dose monitor. In this case, the above-described preparation work may be performed under illumination conditions in which the illumination light amount is intentionally reduced by, for example, selectively putting an ND filter constituting the energy rough adjuster 34 on the illumination optical path. . In this case,
Actual may be performed calculation of the dose Q ₁ at the time of exposure in consideration of the extinction ratio of the ND filter.

Next, the wafer reflectance R _W , which is also assumed to be the same,
The method of measuring is described.

First, two reflectors (not shown) each having a known reflectance _RH and a known reflectance _RL are set on the Z tilt stage 58. Next, similarly to the irradiation light amount measurement described above, the main controller 50 sets the same exposure conditions (reticle R, reticle blind 30B, illumination conditions) as those in the actual exposure, and drives the XY stage 14 for installation. The reflecting plate having the obtained reflectance _RH is moved directly below the projection optical system PL.
Next, the main controller 50 oscillates the light source 16 to move the reticle stage RST and the XY stage 14 synchronously under the same conditions as the actual exposure, while outputting the output V _{H0 of the} reflected light monitor 47.
And the output I _{H0 of the} integrator sensor at the same time at a predetermined sampling interval, so that the output V _H0 of the reflected light monitor 47 corresponding to the synchronous movement position (scanning position) and the output I _{H0 of} the integrator sensor 46 corresponding thereto.
Is stored in the memory 51. Thus, the output V _H0 of the reflected light monitor 47 and the output I _H0 of the integrator sensor 46 are stored in the memory 51 as a function according to the scanning position of the reticle R. Next, in the main controller 50,
The XY stage 14 is driven to move the installed reflection plate of the reflectance _RL directly below the projection optical system PL, and the output V _L0 of the reflected light monitor 47 and the output I of the integrator sensor 46 are moved in the same manner as described above. _L0 is stored in the memory 51 as a function corresponding to the scanning position of the reticle R.

The main controller 50 executes such a preparation operation prior to the exposure. Then, at the time of actual exposure, the output of the reflected light monitor 47 and the output of the integrator sensor 46 stored according to the scanning position of the reticle R, and the output V ₁ of the reflected light monitor and the output I of the integrator sensor 46 at the time of exposure. based on _1, wafer reflectivity R _W
Is calculated based on the following equation (2), and is used for calculating the illumination light absorption.

[0163]

(Equation 1)

According to the equation (2), since the output ratio of the integrator sensor 46 is used for calculation, the light source 16
Can be accurately calculated even when the power varies.

Next, a method for calculating the amount of change in the imaging characteristics due to the absorption of illumination light will be described by taking focus as an example.

The dose Q ₁ obtained as described above,
From the wafer reflectivity R _W using a model function represented by the following formula (3) to calculate a focus variation F _HEAT with illumination light absorption in projection optical system PL.

[0167]

(Equation 2)

Here, F _HEAT : Focus change due to illumination light absorption Δt: Calculation interval of focus change due to illumination light absorption T _Fk : Focus change time constant due to illumination light absorption F _HEATk : Focus change before time Δt due to illumination light absorption the time constant T _Fk component C _FHK: constant T _Fk component when the focus change rate with respect to the illumination light absorption alpha _F: a wafer reflectivity dependency.

The model function of the above equation (3) has the form of the sum of three first-order lag systems when the irradiation amount is regarded as input and the focus change is regarded as output. Note that the model function may be changed depending on the amount of illumination light absorbed by the projection optical system PL and the required accuracy. For example, if the illumination light absorption amount is relatively small, the sum of two first-order delay systems may be used, or one primary-order delay system may be used. Further, if it takes time due to heat conduction until the projection optical system PL absorbs the illumination light and appears as a change in the imaging characteristic, a model function of a waste time system may be employed. In addition, the wafer reflectivity dependency is usually 1, but depending on the type of the projection optical system PL, for example, when glass having a large absorptance is used as a material on the side closer to the wafer W, the dependency greatly depends on the reflectivity. is there. This time will be a value greater than 1 is set to alpha _F. Value smaller than 1 is set in the alpha _F when its absorption rate closer to the opposite to the wafer W is adopted small glass. The focus change time constant due to illumination light absorption, the focus change rate with respect to illumination light absorption, and the wafer reflectance dependency are all determined by experiments. Alternatively, it may be calculated by a highly accurate thermal analysis simulation.

By the same method as the above-mentioned focus, it is possible to calculate a change due to absorption of illumination light for other image forming characteristics, for example, magnification, distortion and the like.

In the above-described focusing, a model function of the sum of three first-order lag systems is required. However, for example, it is considered that one first-order lag system is sufficient for calculating the curvature of field. The model function of the illumination light absorption may be changed for each imaging characteristic according to the required accuracy. When the first-order lag system uses two or one model function, there is an effect of reducing the calculation time.

Next, at a predetermined time, for example, at the time of assembling or starting up the device, the aerial image measuring device 5
Regarding a method of detecting a projected image of a measurement mark on a reticle R using 9C and a method of calculating an imaging characteristic using the same,
The magnification will be described as an example.

As a premise, it is assumed that four measurement marks 90 _{-1 to} 90 _-4 are formed on reticle R as shown in FIG. Each measurement mark 90
_-n (n = 1 to 4) is equal to X as shown in FIG.
One set of the mark Mx and the Y mark My forms one measurement mark. The X mark Mx and the Y mark My have a line and space (L / S) mark pattern including five bar marks.

For example, the measurement mark 90_-1X-ma that constitutes
When detecting the projected image of the mark Mx, the main controller 50
Drives the movable reticle blind 30B to measure
K90 _-1Make sure that only small areas, including parts, are illuminated.
The opening of the moving reticle blind 30B is set and the projection light
An opening 5 on the light receiving glass 82 immediately below the optical axis AX of the science system PL
XY stage so that the reflection film 83 on the −X side of 9f is located.
Page 14 is moved. In this state, the X mark Mx
The detection of the projection image is started.

At this start position, when the X mark Mx is illuminated by the exposure light IL from the illumination optical system 12, this X mark
The projection image Mx ′ of the X mark Mx is formed on the reflection film 83 on the −X side of the opening pattern 59f on the light receiving glass 82 by the exposure light IL transmitted through the mark Mx portion (five bar marks). The state at this time is shown in FIG.

Then, main controller 50 moves XY stage 14 at a predetermined speed in the −X direction via wafer stage drive unit 56. As a result, the projected image Mx ′ of the X mark Mx gradually overlaps the opening 59f from the right side. As the overlap between the projection image Mx 'of the X mark Mx and the opening 59f increases, the amount of light incident on the optical sensor 2 constituting the aerial image measuring device 59C increases, and the projection image Mx' of the X mark Mx and the opening 59f The light amount is the maximum when the light beams overlap. Thereafter, when the XY stage 14 further moves in the −X direction, the amount of light incident on the optical sensor 2 gradually decreases, and the projected image Mx ′ of the X mark Mx and the opening 59
The light amount incident on the optical sensor 2 when the overlap of f disappears is zero.

FIG. 16A shows the change in the light amount at this time. In the main control device 50, the waveform of the light amount signal P as shown in FIG. 16A (actually, digital data captured at a predetermined sampling interval)
Is differentiated with respect to the scanning direction to calculate a differentiated waveform as shown in FIG. As is clear from FIG. 16B, when the front edge of the opening 59f in the scanning direction crosses the projected image Mx 'of the X mark, the light amount gradually increases, that is, the differential waveform becomes positive. Conversely, when the rear edge of the opening 59f in the scanning direction crosses the projected image Mx 'of the X mark Mx, the light amount gradually decreases, that is, the differential waveform becomes negative.

In the main controller 50, FIG.
A known signal processing such as a Fourier transform method is performed on the basis of the differential waveform shown in (1) to detect an optical image (aerial image) on which the X mark Mx is projected.

[0179] Then, the detection of the optical image Y mark My constituting the measuring mark 90 _-1 is projected (aerial image) is performed in the same manner as described above.

Thus, the measurement mark 90_-1Is projected
When the detected aerial image is completed, the main controller 50
Drives the movable reticle blind 30B to measure
K90 _-2, 90_-3, 90_-FourWhile lighting the parts sequentially,
Measurement mark 90_-2, 90_-3, 90 _-FourOf the projected aerial image
Detection is performed as described above.

With the above measurement sequence, the aforementioned
Thus the measurement mark 90_-1~ 90_-FourThe projected image of
Then, main controller 50 measures the measurement pattern based on the projection image.
Arc 90_-1~ 90_-FourOf the XY coordinate position (X_i,
Y_i) (I = 1 to 4), and based on the measured value, X_Four
And X₁The absolute value of the difference ΔX₁, X_ThreeAnd X_TwoThe absolute value of the difference from
X_Two, X_FourAnd X_TwoThe absolute value of the difference ΔX_Three, X₁And X_ThreeAbsolute difference
Logarithmic ΔX_Four, And Y_FourAnd Y _ThreeAnd the absolute value of the difference ΔY₁, Y₁When
Y_TwoAnd the absolute value of the difference ΔY_Two, Y_FourAnd Y_TwoThe absolute value of the difference Δ
Y_Three, Y₁And Y_ThreeAnd the absolute value of the difference ΔY_FourRespectively, and
Absolute value of these differences ΔX_i, ΔY_i(I = 1-4) and it
Design value ΔX of absolute value of difference corresponding to each_P1, ΔX_P2, Δ
X_P3, ΔX_P4And ΔY_P1, ΔY_P2, ΔY_P3, ΔY_P4And
And in the X and Y directions based on the following equations (4) and (5).
Magnification shift ΔM_xi, ΔM_yiIs calculated.

ΔM _xi = ΔX _i / ΔX _Pi (i = 1 to 4) (4)

ΔM _yi = ΔY _i / ΔY _Pi (i = 1 to 4) (5)

The main controller 50 gives a command value of the drive amount of the lens element for correcting the above-mentioned magnification change ΔM _xi to the imaging characteristic correction controller 78, and the imaging characteristic correction controller 78 makes the above-mentioned magnification change ΔM _xi Are driven to drive the driving elements 74a, 74b, 74c. Thus, the measurement of the magnification change and the correction of the magnification in the non-scanning direction are completed. The change in magnification in the scanning direction can be easily corrected, for example, by adjusting the scanning speed of at least one of the reticle stage RST and the XY stage 14 during scanning exposure and changing the speed ratio.

In this case, as shown in FIG. 14 (B), each measurement mark is composed of a mark in two directions of an X mark and a Y mark.
The magnification shifts ΔM _xi and ΔM _yi in the direction can be respectively measured. By using these data separately, not only the magnification but also the distortion can be measured.

By detecting the projection images (aerial images) of the plurality of measurement marks arranged on the reticle R using the detection method described above, the imaging of the magnification and distortion of the projection optical system PL is performed. Characteristics can be determined.

In the above detection method, the measurement mark 90
_Since the projection image of _-n is directly detected, it is possible to see the optical performance of the projection optical system PL including magnification and distortion.

If the Z-tilt stage 58 is driven in the Z-direction for any one of the above-mentioned measurement marks and the Z-position is changed within a predetermined range, the aerial image detection is performed. The focus position (or focus offset) and the depth of focus can be detected based on the contrast of the image (the amplitude of the differential waveform data). Further, the telecentricity of the projection optical system PL can be detected based on the position in the X direction (or Y direction) of the aerial image at each Z position. Further, it is possible to calculate the image plane inclination (or leveling offset) and other image forming characteristics (for example, field curvature) based on the data of the focal position obtained for each of at least three measurement marks.

The method of detecting the imaging characteristics such as the magnification by the aerial image measuring device is described in, for example,
No. 209031, disclosed in detail,
A method of detecting the focus offset and the leveling offset by the same detection means as that of the aerial image measuring device is disclosed in detail, for example, in Japanese Patent Application Laid-Open No. 9-283421. Also in the present embodiment, the contents disclosed in these publications can be used as they are or partially modified.

Next, an exposure sequence when a reticle pattern is exposed on a predetermined number (N) of wafers W in exposure apparatus 10 of the present embodiment will be described.
The following description focuses on the control operation.

First, the preconditions will be described. I / O device 62 such as console by operator
Based on the shot arrangement, shot size, exposure order of each shot, and other necessary data input from FIG. 1 (see FIG. 1), shot map data (data in which the exposure order and scanning direction of each shot area are determined in advance) are generated. It is assumed that it is created and stored in the memory 51 (see FIG. 1). The output DS of the integrator sensor 46 is Z
The output of the reference illuminometer 90 installed at the same height as the image plane (that is, the surface of the wafer) on the tilt stage 58 is calibrated in advance as described above. The data processing unit of the reference illuminometer is (mJ / (c
m ² · pulse)), and the calibration of the integrator sensor 46 means the output DS of the integrator sensor 46.
(Digit / pulse) to the exposure amount on the image plane (mJ / (cm ² · pu)
lse)) to obtain a conversion coefficient K1 (or a conversion function). Using this conversion coefficient K1,
The exposure amount (energy) given indirectly to the image plane can be measured from the output DS of the integrator sensor 46. In addition, the output DS of the integrator sensor 46 for which the calibration has been completed is applied to the beam monitor 1.
The output ES of 6c is also calibrated, and the correlation coefficient K2 between them is also obtained in advance and stored in the memory 51. Further, the output of the reflected light monitor 47 is calibrated with respect to the output of the integrator sensor 46 for which the above calibration is completed, and the correlation coefficient K3 between the output of the integrator sensor 46 and the output of the reflected light monitor 47 is obtained.
Is obtained in advance and stored in the memory 51.

First, the illumination conditions (numerical aperture NA of the projection optical system, the shape of the secondary light source (the type of the aperture stop 24), the coherence factor σ) are input by the operator from the input / output device 62 (see FIG. 1) such as a console. And exposure conditions including the type of reticle pattern (contact hole, line and space, etc.), the type of reticle (phase difference reticle, halftone reticle, etc.), and the minimum line width or exposure tolerance). According to the main controller 50
Are the setting of the aperture stop (not shown) of the projection optical system PL, the selection setting of the aperture of the illumination system aperture stop plate 24, the energy coarse adjuster 20.
, And setting of a target integrated exposure amount according to the resist sensitivity.

Next, main controller 50 loads reticle R to be exposed onto reticle stage RST using a reticle loader (not shown).

Next, as described above, reticle alignment is performed using reticle alignment system 100, and baseline measurement is performed.

Next, the main controller 50 measures the transmittance of the optical system as follows. That is, the unevenness sensor 5
The XY stage 14 is driven via the wafer stage driving unit 56 so that the 9B is located immediately below the projection optical system PL, and a trigger pulse is applied to the light source 16 to cause the light source 16 to oscillate (emit light). The transmittance is obtained by multiplying the ratio between the output of the sensor 46 and the output of the unevenness sensor 59B by 100 and multiplying the ratio by a predetermined coefficient (K4). At this time, the unevenness sensor 59B may be positioned at each of a plurality of points in the exposure area 42W while the wafer stage 14 is stepped, and an average value of the transmittance calculated at each of the plurality of points may be used. Further, by this measuring operation, not only the transmittance but also the illuminance distribution in the exposure area 42W can be obtained. In addition, the unevenness sensor 59B is positioned at each of the above-described plurality of points, and
In addition, the unevenness sensor 59B may be positioned again at the plurality of points in the reverse order, and the illuminance distribution may be determined from the average value of the two illuminances measured at each point. In this case, since the forward path and the backward path are reverse paths, that is, the measurement order is reversed, the irradiation of the exposure light IL causes
Drift (particularly, a linear component) of the output of the unevenness sensor 59B caused by the thermal energy stored in 9B can be canceled. Furthermore, even if the transmittance of the optical system (including the projection optical system PL and the like) arranged between the beam splitter 26 and the unevenness sensor 59B fluctuates during a series of measurement operations by the unevenness sensor 59B, the transmittance is changed by the reciprocating operation. The influence of the fluctuation can be reduced, and in particular, the linear component can be corrected, and the measurement accuracy of the illuminance distribution can be improved.

Next, main controller 50 instructs a wafer transfer system (not shown) to replace wafer W. As a result, the wafer is exchanged (mere wafer loading when there is no wafer on the stage) by the wafer transfer system and a wafer transfer mechanism (not shown) on the XY stage 14, and then so-called search alignment and fine alignment (such as EGA) Is performed in a series of alignment steps.
Since the wafer exchange and wafer alignment are performed in the same manner as in a known exposure apparatus, further detailed description is omitted here.

Next, based on the alignment result and the shot map data, the operation of moving the wafer W to the scanning start position for exposure of each shot area on the wafer W and the above-described scanning exposure operation are repeated. Then, the reticle pattern is transferred to a plurality of shot areas on the wafer W by a step-and-scan method. During this scanning exposure, the main controller 50 sends the control information TS to the light source 16 while monitoring the output of the integrator sensor 46 in order to give the target integrated exposure amount determined according to the exposure condition and the resist sensitivity to the wafer W. By supplying the reticle R, the oscillating frequency (light emission timing) and the light emission power of the light source 16 are controlled, or the light amount irradiated to the reticle R by controlling the energy rough adjuster 20 via the motor 38, that is, Adjust the exposure. At this time, exposure control is performed based on the transmittance measured above and the exposure control target value. Further, the integrated exposure amount distribution is made substantially uniform based on the previously measured illuminance distribution. For example, as disclosed in JP-A-59-226317 and the like, the incident angle of the illumination light incident on the fly-eye lens 22 is changed for each pulse by a vibrating mirror arranged on the incident surface side of the fly-eye lens 22. Just change it. As a result, the illuminance distribution in the exposure area 42W changes for each pulse, and the integrated exposure amount distribution in the shot area becomes substantially uniform.

The method of controlling the amount of exposure by the main controller 50, particularly the control of the number of pulses, is described in, for example,
For example, Japanese Patent Application Laid-Open No. 10-270345 discloses details of exposure control including pulse energy, pulse oscillation frequency, and scanning speed. Therefore, further description is omitted here, but the disclosure in each of the above publications can be used as it is or in a partially modified manner in the exposure apparatus 10 of the present embodiment.

The main controller 50 controls the illumination system aperture stop plate 24 via the driving device 40, and further synchronizes with the operation information of the stage system to move the movable reticle blind 30B.
Control the opening and closing operations of

When exposure of the first wafer W is completed, main controller 50 instructs a wafer transfer system (not shown) to replace wafer W. As a result, the wafer is exchanged by the wafer transfer system and the wafer transfer mechanism (not shown) on the XY stage 14, and thereafter, search alignment and fine alignment are performed on the replaced wafer in the same manner as described above. In this case, the first wafer W
Is obtained based on the measurement values of the integrator sensor 46 and the reflected light monitor 47 from the start of the exposure of the projection optical system PL (including the fluctuation of the focus) from the start of the exposure, and the irradiation fluctuation is corrected. The command value is given to the imaging characteristic correction controller 78 and the light receiving optical system 6
0b is given an offset.

Then, as described above, a reticle pattern is transferred to a plurality of shot areas on wafer W by a step-and-scan method.

When the exposure of a predetermined number (M of wafers) of the wafers W, which is determined in advance as the transmittance measurement interval, is completed, the transmittance of the optical system is measured in the same manner as described above. Is stored in the memory 51, that is, the measured value of the transmittance is updated.

Thereafter, in the same manner as described above, each time M wafers are exposed, the transmittance of the optical system is repeatedly measured.
When the exposure for the N-th wafer W is completed, a series of exposure processing ends. Note that, between the transmittance measurements, the transmittance measured immediately before may be used as a fixed value, or the transmittance variation may be sequentially updated by calculation and the calculated value may be used. This may be determined according to the transmittance measurement interval or the like.

As is clear from the above description, in this embodiment, the transmittance measuring device is constituted by the integrator sensor 46, the irradiation amount monitor 59A and the main controller 50. Further, in the present embodiment, the piezoelectric elements 74a, 74b, 74c for driving the lens element 70a,
The imaging characteristic correction controller 78 and the main controller 50 constitute an imaging characteristic adjustment device. In the present embodiment, the main controller 50 includes an exposure controller (exposure amount control system) and a stage controller (stage control system).
Also has the role of. Needless to say, these controllers may be provided separately from main controller 50.

In the exposure apparatus 10 of this embodiment, the light source 16
Since the optical sensor 2 having the GaN-based semiconductor light receiving element 17 as described above is used as the beam monitor 16c in the housing, the light receiving element 17 has a carrier layer existing on the surface thereof. Ultraviolet light (ArF excimer laser light) oscillated from the laser resonator 16a
LB intensity (power) can be detected with good stability. Therefore, the deterioration of measurement reproducibility and the deterioration over time due to the poor sensitivity of the beam monitor 16c are suppressed, and unnecessary output fluctuation of the beam monitor 16c is reduced. It is possible to suppress the occurrence of an exposure amount control error). In this case, there is no need to frequently change the beam monitor 16c. Of course, the center wavelength and the half-width of the spectrum of the pulsed ultraviolet light LB may be detected and maintained within a predetermined allowable range.

In a scanning type exposure apparatus having a laser light source (pulse light source) such as the exposure apparatus 10 of the present embodiment, the scanning speed (scanning speed) of the wafer W is set to V _W , and the slit-shaped exposure Assuming that the width (slit width) of the region 42W in the scanning direction is D and the oscillation frequency of the laser light source is F, the interval at which the wafer W moves between pulse emission is V _W /
Since F, the pulse number (number of exposure pulses) N of the pulse exposure light IL to be irradiated per one point on the wafer is expressed by the following equation.

N = D / (V _W / F) (6)

On the other hand, the above-mentioned exposure pulse number N is used to irradiate each point on the wafer W determined based on the known variation Epσ of the pulse energy of the light source 16 in order to obtain necessary exposure amount control reproduction accuracy. It must be equal to or greater than the minimum pulse number N _min of the exposure light IL to be performed.

From the above equation, the number of exposure pulses N and the scanning speed V _W
Is inversely proportional, it is assumed that the slit width D and the oscillation frequency F are constant, and the scanning speed is improved as the number N of exposure pulses, and therefore the minimum number of exposure pulses (minimum pulse oscillation number) _Nmin, is smaller. be able to.

In this embodiment, the intensity (power) of the pulsed ultraviolet light LB oscillated from the laser resonator 16a can be detected with high accuracy and high sensitivity by the beam monitor 16c with high stability. Variation Ep
σ becomes small, and the minimum number N _min of exposure pulses required to achieve the irradiation energy error Eσ permitted at the time of exposure (to obtain the necessary exposure amount control reproduction accuracy) can be reduced, thereby increasing the scanning speed ( It is possible to improve the throughput by improving the scanning speed.

Further, the integrator sensor 46 having the above-mentioned optical sensor 2 makes it possible to detect the light intensity of the exposure light IL with high accuracy, high sensitivity, and excellent stability, and to perform measurement reproducibility due to poor sensitivity of the integrator sensor 46. And the deterioration over time are suppressed, so that the occurrence of measurement errors by the integrator sensor 46 due to this is suppressed, and it is possible to estimate the image plane illuminance over a long period of time with high accuracy. The output of the integrator sensor 46 is
Since it is used for normalization for preventing the fluctuation of the measurement values of the other sensors due to the fluctuation of the power, the occurrence of the measurement error of those sensors is also suppressed.

Further, the output of the integrator sensor 46 is used as a reference for other sensors.
Since the accuracy of exposure amount matching with another exposure apparatus (other unit) after calibration using 0 can be maintained well over a long period of time, and the maintenance interval for the calibration can be lengthened, MTBF (mean time between failur
es) or MTTR (mean time to repair).

As described above, the main controller 50 estimates the image plane illuminance based on the output of the integrator sensor 46 and controls the exposure so that the integrated exposure on the wafer W becomes the target exposure. As a result, the light intensity of the exposure light IL can be detected with high accuracy, high sensitivity, and stably by the integrator sensor 46. As a result, the exposure amount control accuracy and the pattern line width accuracy formed on the wafer W can be improved. Will be possible.

In this embodiment, the main controller 50
However, since the transmittance of the optical system is measured at predetermined intervals using the unevenness sensor 59B, and the exposure amount is controlled in consideration of the fluctuation of the measured transmittance, the exposure amount control is more highly accurate. Thus, exposure with higher precision is possible. Further, a non-uniformity sensor 59B used for measuring the transmittance.
Semiconductor light receiving element 17 as a light receiving element constituting
, Even if the exposure operation is continued for a long time,
The unevenness sensor 59B can accurately measure the light intensity of the exposure light IL passing through the projection optical system PL on the image plane, so that the transmittance of the optical system is measured with high accuracy, high sensitivity, and stably. be able to.

In the present embodiment, the dose monitor 5 having an opening 59d having an area capable of receiving the exposure light IL applied to the entire surface of the illumination field (exposure area 42W) at one degree.
Using the optical sensor 2 having the GaN-based semiconductor light receiving element 17 as 9A, calculating the irradiation variation of the imaging characteristic of the projection optical system PL based on the measurement value of the optical sensor, and correcting the imaging characteristic accordingly. Therefore, it is possible to maintain a good imaging state. Of course, the variation in irradiation of the reticle R may be obtained based on the measurement value of the irradiation amount monitor 59A, and the imaging characteristics of the projection optical system may be corrected in consideration of this. Also, when the illumination condition is changed, the irradiation amount monitor 59
By A, the light intensity on the image plane of the exposure light IL passing through the projection optical system PL can be accurately measured, and accordingly, the basic data of the irradiation variation calculation of the imaging characteristics can be corrected accordingly. It is.

In this embodiment, the irradiation amount sensor 59
(Specifically, the irradiation amount monitor 59 for measuring the illuminance of the image plane
A, based on the measurement values of the unevenness sensor 59B and the aerial image measuring device 59C used for transmittance measurement, the imaging characteristics of the projection optical system PL are changed by the imaging characteristics adjusting devices (74a to 74c, 78, 50). Since the adjustment is automatically performed, the adjustment operation of the imaging characteristics can be partially or entirely automated.

In the present embodiment, the imaging characteristic adjusting device adjusts the imaging characteristic (mainly irradiation variation) of the projection optical system PL in further consideration of the output of the reflected light monitor 47. That is, the reflectivity of the wafer W is calculated as described above based on the output of the integrator sensor 46 and the output of the reflected light monitor 47 during exposure, and the irradiation variation amount of the projection optical system PL is considered in consideration of the calculation result. Is obtained and corrected by the image forming characteristic adjusting device, so that the image forming characteristic caused by the irradiation fluctuation of the projection optical system PL can be corrected more accurately.
Further, G is used as a light receiving element constituting the reflected light monitor 47.
Since the aN-based semiconductor light receiving element 17 is used, even if the exposure operation is continued for a long time, the reflected light from the reticle R and the projection optical system P
It is possible to accurately measure the intensity of the exposure light IL that returns after passing through L, and hence the reflectivity of the wafer W, whereby the imaging characteristic adjustment device causes the projection optical system to emit light due to the above-described irradiation fluctuation of the projection optical system. Image characteristics can be corrected more accurately.

A reference illuminometer 90, which is removably mounted on the Z tilt stage 58 and calibrates the exposure amount on the substrate between a plurality of exposure apparatuses, is
Since the optical sensor having the aN-based semiconductor light receiving element 17 is used, the calibration (calibration) for matching the exposure amount on the substrate between the devices (illuminance matching) can be performed with high accuracy. Further, an optical sensor having a GaN-based semiconductor light receiving element 17 is used as the illuminance unevenness sensor 59B capable of measuring the in-plane illuminance unevenness of the irradiation amount of the exposure light IL in a predetermined illumination field by two-dimensionally moving the Z tilt stage 58. Therefore, it is possible to accurately measure the unevenness of the illumination via the optical system including the projection optical system PL on the substrate surface (image surface), and to adjust the unevenness of the illumination accurately based on the value. The integrated exposure dose distribution can be made uniform, thereby improving the accuracy of the pattern line width transferred and formed on the wafer W.

In this embodiment, the image of the measurement pattern formed on the reticle R is relatively scanned with the opening 59f of the light receiving surface (illuminated surface) provided on the Z tilt stage 58, and the opening 59f is Since the optical sensor 2 having the GaN-based semiconductor light receiving element 17 is used as the aerial image measuring device 59C for receiving the transmitted exposure light IL by the optical sensor, the reticle R is provided by the aerial image measuring device 59C.
Alternatively, information for determining the positional relationship between the imaging plane of the projection optical system PL and the wafer W can be detected with high accuracy.
For example, when the relative scanning is performed on a plurality of measurement patterns on a reticle in an XY two-dimensional plane, a spatial image of each measurement pattern is measured based on the output of the optical sensor 2 and a projection optical system is obtained from the measurement result of the spatial image. High-precision detection of imaging characteristics in the XY plane direction (a kind of information serving as a reference for determining the positional relationship (overlay offset) of the reticle R and the wafer W in the XY plane) such as PL magnification and distortion. Can be. Further, for example, by changing the position of the Z tilt stage 58 in the Z direction orthogonal to the XY plane during the relative scanning, or by repeatedly performing the relative scanning while changing the Z position of the Z tilt stage 58, For example, a focus offset which is information serving as a reference for determining a positional relationship between the reticle R and the wafer W in the Z direction based on a change in contrast of a differential signal of the output of the optical sensor 2, a focus position of the projection optical system PL, and a telecentric City,
Alternatively, the depth of focus and the like can be detected with high accuracy.
Further, the detection of the focus offset is performed by using a reticle R
By performing the measurement for at least three different measurement marks, a leveling offset (a shape or an image plane of an image plane of the projection optical system) serving as a reference for determining a relative positional relationship between the reticle R and the wafer W in the θx and θy directions. Curvature) can be detected with high accuracy. Therefore, by adjusting the magnification or the like of the projection optical system PL according to the above detection result, or by performing focus leveling control based on the focus offset and the leveling offset, the overlay accuracy (overlay accuracy) of the reticle R and the wafer W is achieved. In addition, it is possible to improve the line width control accuracy.

Also, the relative position between the plurality of reference marks (mark patterns) formed on the reference mark plate FM and the projected images of the reticle marks (mark patterns) formed on the reticle corresponding to these reference marks are detected. Since the GaN-based semiconductor light-receiving elements 17 arranged in a matrix are used as the two-dimensional image pickup device constituting the reticle alignment system 100 to perform the reticle alignment system 100, the projected image of each of the above-described marks is converted into a predetermined two Dimensional images can be detected with high accuracy. In this case, the overlay offset can be obtained with high accuracy based on the in-plane positional deviation between the projection images, so that the overlay accuracy can be improved. In this case, it is possible to obtain a focus offset and a leveling offset based on the contrast of the detection signal of the projection image,
By performing the focus leveling control based on this, it is possible to improve the line width control accuracy.

Further, in the exposure apparatus 10 of the present embodiment,
ArF excimer laser light having a wavelength of 193 nm or KrF excimer laser light having a wavelength of 248 nm or less is used as the exposure light IL. However, a conventional ultraviolet light in such a wavelength band cannot be detected stably for a long period of time. Unlike a PD (photodiode) using a Si-based crystal, the GaN-based semiconductor light-receiving element 17 constituting each optical sensor can detect the exposure light IL with high accuracy, high sensitivity, and stability. It becomes possible. Therefore, in the present embodiment, by performing exposure using an energy beam having a short wavelength, the resolution of the projection optical system PL is improved,
High-precision exposure becomes possible.

In summary, in the present embodiment, in the present embodiment, the beam monitor 16c, the integrator sensor 46, the reflected light monitor 47, the irradiation amount sensor 59 (the irradiation amount monitor 59A, the unevenness sensor 59B, the aerial image measuring instrument 59C), the reticle alignment system A GaN-based semiconductor light-receiving element 17 as a light-receiving element constituting each optical sensor such as the imaging elements 104R and 104L
Therefore, there is an effect on improvement of total overlay accuracy, improvement of line width control accuracy, improvement of device stability, improvement of matching accuracy between devices, and improvement of throughput without replacing each optical sensor for a long time.

However, it is not always necessary to use the GaN-based semiconductor light-receiving element 17 or a light-receiving element similar to the GaN-based semiconductor light-receiving element for all of the above-mentioned optical sensors, and it is also possible to use only any of the optical sensors. For example, the above-mentioned GaN is mainly used for a sensor part having a high luminance and a sensor part used for calibration.
The system semiconductor light receiving element 17 or a light receiving element similar thereto may be used, and the other parts may use the conventional Si semiconductor light receiving element. In such a case, the cost can be reduced.

In the present embodiment, Ga is assigned to each optical sensor.
Although an N-based semiconductor light-receiving element is used, impurities directly adhering to the surface of the optical sensor due to a chemical reaction with an illumination light beam may cause a deterioration in sensor sensitivity, so in practice, use quartz or fluorite. The cover surrounding the optical path is made detachable, the inside of the cover is purged with an inert gas such as nitrogen, helium, argon, krypton, etc., and a means for flowing (flowing) the inert gas is provided. It is important to use a technique for cleaning the sensor surface by so-called light cleaning.

Although not particularly described in the above embodiment, in the case of an apparatus for performing exposure at an exposure wavelength of 248 nm or less as in this embodiment, the light beam passing portion is passed through a chemical filter. It is necessary to take measures such as filling or flowing clean air, dry air, N ₂ gas, or an inert gas such as helium, argon, or krypton, or evacuating the light passing portion.

Further, the GaN-based semiconductor light receiving element 1 described above
Since outgas from the optical sensor having 7 may cause fogging of other optical members, the sensor has a hierarchical structure such as an adhesive that prevents degassing,
It is desirable to provide an air-conditioning mechanism for preventing the generated gas from being emitted to the outside as an optical contact and further a negative pressure.

In the above embodiment, the case where the measurement of the projection image (aerial image) of the measurement mark on the reticle R is performed using the aerial image measuring device on the Z-tilt stage has been described. A wavefront aberration measuring device, which is a kind of detachable irradiation amount sensor, may be provided on the Z tilt stage, and the imaging characteristic of the projection optical system may be measured by the wavefront aberration measuring device.

FIG. 17 is a sectional view showing an example of the wavefront aberration measuring instrument 120 installed at a predetermined position on the Z tilt stage. The wavefront aberration measuring device 120 is detachably mounted on the Z tilt stage 58 near the place where the sensor head unit 90A of the reference illuminometer 90 is installed. The wavefront aberration measuring device 120 includes a case 122 having an open upper surface, an image sensor 124 similar to the image sensor 104R described above with reference to FIG. 10 fixed to the bottom plate 122a of the case 122, and an upper open end of the case 122 closed. And a light receiving glass 126 to be used. A light shielding film 128 is formed on the upper surface of the light receiving glass 126 by a chrome layer or the like.
A predetermined opening 130a and a pinhole-shaped opening 130b are formed in a part of the light shielding film. Also,
A bending mirror 132 is obliquely arranged at an angle of 45 ° substantially below the opening 130a, and a half mirror 134 is disposed substantially directly below the opening 130b in parallel with the bending mirror. The image sensor 124 is connected to the cable 13
6, a main body data processing unit (not shown) is connected to the control system of the exposure apparatus 10 online, and is configured to be able to communicate measurement data and the like. .

According to the wavefront aberration measuring device 120, one light beam (plane wave) LL1 emitted from the projection optical system PL and traveling toward the opening 130a passes through the opening 130a and the light receiving glass 126, and is bent by the bending mirror 132 and the half mirror 134. Are sequentially reflected toward the image sensor 124. On the other hand, the other light beam LL2 emitted from the projection optical system PL and traveling toward the opening 130b is converted from a plane wave to a spherical wave by passing through the opening 130b, and
26, the light beam LL
1 and are combined coaxially with each other and head toward the image sensor 124. For this reason, an interference fringe due to interference between the plane wave and the spherical wave forms an image on the light receiving surface of the image sensor 124, and an image signal of the interference fringe is sent to a data processing unit (not shown) via the cable 136.
Therefore, the wavefront aberration of the projection optical system is required. And
The measurement data of the obtained wavefront aberration is sent from the data processing unit to the control system of the exposure apparatus 10, that is, the main control unit 50. Main controller 50 corrects the imaging characteristics of projection optical system PL via imaging characteristic correction controller 78 based on the measurement data of the wavefront aberration.

As described above, when the wavefront aberration measuring device 120 is used, a technique of detecting an image of interference fringes is employed, and therefore, it is difficult to accurately detect the imaging characteristics by the aerial image measuring device 59C described above. Even in this case, it is possible to measure the wavefront aberration of the projection optical system with high accuracy, for example, when assembling the apparatus, when starting up after transporting, when returning from an emergency such as a power failure, etc., the projection can be accurately performed. It becomes possible to adjust the imaging characteristics of the optical system. The adjustment operation of the imaging characteristics in such a case may be performed completely manually. However, in the present embodiment, the adjustment operation is automatically performed by the main controller 50 via the imaging characteristic correction controller 78 as described above. Therefore, the burden on the worker is reduced correspondingly.

The exposure apparatus of the above embodiment assembles various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. It is manufactured by. Before and after this assembly, adjustments to achieve optical accuracy for various optical systems, adjustments to achieve mechanical accuracy for various mechanical systems, and various electric systems to ensure these various accuracy Are adjusted to achieve electrical accuracy. The process of assembling the exposure apparatus from various subsystems includes mechanical connections, wiring connections of electric circuits, and piping connections of pneumatic circuits among the various subsystems. It goes without saying that there is an assembling process for each subsystem before the assembling process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed, and various precisions of the entire exposure apparatus are secured. It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

In each of the above embodiments, the case where the present invention is applied to a step-and-scan type scanning exposure apparatus has been described. However, the scope of the present invention is not limited to this. The present invention can also be suitably applied to a static exposure type, for example, a step-and-repeat type exposure apparatus (such as a stepper). Further, the present invention can be applied to a step-and-stitch type exposure apparatus, a mirror projection aligner, and the like.

In each of the above embodiments, in each of the above embodiments, the present invention uses A
The case where the present invention is applied to an exposure apparatus using excimer laser light such as rF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), or F ₂ excimer laser light (wavelength 157 nm) has been described.
The present invention is not limited to this, and the present invention can be suitably applied to an exposure apparatus using vacuum ultraviolet light such as Kr ₂ laser light having a wavelength of 146 nm and Ar ₂ laser light having a wavelength of 126 nm.

Further, a single-wavelength laser beam in the infrared or visible range oscillated from a DFB semiconductor laser or a fiber laser is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and yttrium), and nonlinearly amplified. It is also possible to use a harmonic whose wavelength has been converted to ultraviolet light using an optical crystal.

For example, the oscillation wavelength of a single wavelength laser is set to 1.
When the wavelength is in the range of 51 to 1.59 μm, the generated wavelength is 18
An eighth harmonic having a wavelength in the range of 9 to 199 nm or a tenth harmonic having a generation wavelength in the range of 151 to 159 nm is output. Especially the oscillation wavelength is 1.544 to 1.553 μm
m, an 8th harmonic having a generation wavelength in the range of 193 to 194 nm, that is, ultraviolet light having substantially the same wavelength as the ArF excimer laser light is obtained, and the oscillation wavelength is set to 1.57.
When it is within the range of 1.58 μm, the generated wavelength is 157 to
The 10th harmonic within the range of 158 nm, that is, ultraviolet light having substantially the same wavelength as the F ₂ laser light is obtained.

The oscillation wavelength is set to 1.03 to 1.12 μm
, A 7th harmonic whose output wavelength is in the range of 147 to 160 nm is output.
When the wavelength is in the range of 099 to 1.106 μm, a 7th harmonic having a generated wavelength in the range of 157 to 158 μm, that is, ultraviolet light having substantially the same wavelength as the F ₂ laser light is obtained. In this case, as the single-wavelength oscillation laser, for example, an ytterbium-doped fiber laser can be used.

The projection optical system and the illumination optical system shown in the above embodiments are only examples, and it goes without saying that the present invention is not limited to these. For example, the projection optical system is not limited to the refractive optical system, but may be a reflective system including only a reflective optical element, or a catadioptric system having a reflective optical element and a refractive optical element (a catadioptric system). Vacuum ultraviolet light (VUV light) with a wavelength of about 200 nm or less
In an exposure apparatus using, a catadioptric system may be used as the projection optical system. As the catadioptric projection optical system, for example, a catadioptric system having a beam splitter and a concave mirror as a reflective optical element, or a catadioptric system disclosed in Japanese Patent Application Laid-Open Nos. A catadioptric system having a concave mirror or the like can be used as a reflective optical element without using a beam splitter as disclosed in Japanese Unexamined Patent Publication No. Hei 8-334695 and Japanese Unexamined Patent Publication No. Hei 10-3039.

In addition, US Pat. No. 5,488,229
And a plurality of refractive optical elements and two mirrors (a primary mirror which is a concave mirror and a reflective surface formed on the side opposite to the incident surface of the refractive element or the parallel flat plate) disclosed in Japanese Patent Application Laid-Open No. 10-104513. And a reflection mirror that re-images an intermediate image of the reticle pattern formed by the plurality of refractive optical elements on the wafer by the primary mirror and the secondary mirror. A refraction system may be used. In this catadioptric system, a primary mirror and a secondary mirror are arranged following a plurality of refractive optical elements, and illumination light is reflected through a part of the primary mirror in the order of a secondary mirror and a primary mirror. Part to reach the wafer.

Of course, not only an exposure apparatus used for manufacturing a semiconductor device, but also an exposure apparatus used for manufacturing a display including a liquid crystal display element for transferring a device pattern onto a glass plate, and manufacturing a thin film magnetic head The present invention can also be applied to an exposure apparatus used to transfer a device pattern onto a ceramic wafer, an exposure apparatus used to manufacture an imaging device (such as a CCD), and the like.

<< Device Manufacturing Method >>

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus and exposure method in a lithography step will be described.

FIG. 18 shows devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads,
The flowchart of the example of manufacture of a micromachine etc. is shown. As shown in FIG.
In 1 (design step), a function / performance design of a device (for example, a circuit design of a semiconductor device) is performed, and a pattern design for realizing the function is performed. Subsequently, in step 202 (mask manufacturing step)
A mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step)
A wafer is manufactured using a material such as silicon.

Next, in step 204 (wafer processing step), using the mask and the wafer prepared in steps 201 to 203, an actual circuit or the like is formed on the wafer by lithography or the like, as described later. . Next, in step 205 (device assembly step), device assembly is performed using the wafer processed in step 204. Step 205 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary.

Finally, step 206 (inspection step)
In step, inspections such as an operation confirmation test and a durability test of the device manufactured in step 205 are performed. After these steps, the device is completed and shipped.

FIG. 19 shows a detailed flow example of step 204 in the case of a semiconductor device. In FIG. 19, step 211 (oxidation step)
In, the surface of the wafer is oxidized. Step 212
In the (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), electrodes are formed on the wafer by vapor deposition. Step 2
At 14 (ion implantation step), ions are implanted into the wafer. Steps 211 to 214 described above
Each of them constitutes a pre-processing step of each stage of wafer processing, and is selected and executed according to a necessary process in each stage.

In each stage of the wafer process, when the above pre-processing step is completed, a post-processing step is executed as follows. In this post-processing step, first, in step 2
In 15 (resist forming step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (exposure step), the circuit pattern of the mask is transferred onto the wafer by the lithography system (exposure apparatus) and the exposure method described above. Next, in Step 217 (developing step), the exposed wafer is developed, and Step 2
In 18 (etching step), the exposed members other than the portion where the resist remains are removed by etching. Then, in step 219 (resist removing step), unnecessary resist after etching is removed.

By repeating these pre-processing and post-processing steps, multiple circuit patterns are formed on the wafer.

By using the device manufacturing method of the present embodiment described above, in the exposure step (step 216),
Exposure is performed by the exposure apparatus of the above-described embodiment using an energy beam having a wavelength of 300 nm or less.
An image of the mask pattern is formed on the substrate at a predetermined resolution and depth of focus based on information measured using a sensor having a light detection unit made of an N-type crystal. Then, the substrate on which the image of the mask pattern is formed is peeled off in a developing step to form a step structure. next,
On the substrate having the same step structure, the processes of the respective processes such as an etching process, a vapor deposition process, and an ion implantation process are hierarchically performed, and a predetermined circuit device is formed. Therefore, it is possible to manufacture a circuit device formed by exposing a line width having a resolution of 0.25 μm to 0.05 μm with a high yield.

[0249]

As described above, according to the exposure apparatus, the light source device, and the exposure method according to the present invention, the exposure accuracy can be maintained at a high level over a long period of time without frequently replacing the optical sensor. There is an effect that can be.

Further, according to the device manufacturing method of the present invention, there is an effect that the productivity of a microdevice having a higher degree of integration can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an exposure apparatus according to an embodiment.

FIG. 2 is a block diagram showing the inside of the light source of FIG. 1 together with a main controller.

3 (A) is a plan view showing a GaN-based semiconductor light receiving element 17 constituting an optical sensor, and FIG. 3 (B) is FIG. 3 (A).
FIG. 7 is a sectional view taken along line BB of FIG.

FIG. 4 is a diagram showing a relationship between a depletion layer of a Schottky barrier and light incidence in the GaN-based semiconductor light receiving element 17;

FIG. 5 is a diagram showing an example of a configuration of an optical sensor including the GaN-based semiconductor light receiving element of FIG.

FIG. 6 is a schematic plan view showing a Z tilt stage.

FIG. 7A is an enlarged view showing a part of the vicinity of the Z tilt stage of FIG. 1 including the aerial image measuring device, partially cut away,
FIG. 8B is an enlarged plan view showing the reflection film portion of FIG.

FIG. 8 shows the condenser lens, reticle,
Projection optical system, Z tilt stage, XY stage, etc.
It is the schematic side view seen in the Y direction.

9 is an enlarged plan view showing a state in which a part of a projection image RP of a reference mark plate FM and a reticle R in FIG. 8 is superimposed.

FIG. 10 is a diagram illustrating an example of a configuration of an image sensor 104R.

FIG. 11 is a schematic plan view showing a sensor head of a reference illuminance meter installed at a predetermined position on a Z tilt stage.

FIG. 12 is a diagram showing a state in which the center position of the sensor head of the reference illuminometer is positioned at the center of the projection optical system.

FIG. 13 is a conceptual diagram showing a state of simultaneous measurement of illuminance by a reference illuminometer and an integrator sensor.

FIG. 14A is a plan view showing an example of a reticle on which a measurement mark is formed, and FIG. 14B is a diagram showing a specific configuration of the measurement mark.

FIG. 15 is a diagram for explaining a photoelectric detection method of a measurement mark projected image.

FIG. 16A is a diagram showing a waveform of a light amount signal obtained as a result of photoelectrically detecting a projected image of the X mark;
(B) is a diagram showing the differential waveform.

FIG. 17 is a cross-sectional view showing a wavefront aberration measuring instrument installed at a predetermined position on a Z tilt stage.

FIG. 18 is a flowchart illustrating an embodiment of a device manufacturing method according to the present invention.

FIG. 19 is a flowchart showing a process in step 204 of FIG. 18;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light receiving layer, 1a ... Light receiving surface, 2 ... Optical sensor, 10 ... Exposure device, 16 ... Light source (light source device), 16c ... Beam monitor (1st optical sensor), 46 ... Integrator sensor (2nd optical sensor) , A part of the transmittance measuring device), 47: a reflected light monitor (third optical sensor), 50: a main controller (a part of an exposure amount control device, an arithmetic device, an imaging characteristic adjusting device, a transmittance measuring device) 58) Z tilt stage (substrate stage), 59A ... Irradiation amount monitor (fifth optical sensor), 5
9B: Unevenness sensor (fourth optical sensor, part of transmittance measuring device, fifth optical sensor), 59C: aerial image measuring instrument (fifth optical sensor)
Optical sensor, sixth optical sensor), 59f: opening pattern (opening), 74a to 74c: driving elements (part of the imaging characteristic adjustment device), 78: imaging characteristic correction controller (imaging characteristic adjustment device) , 83... Reflective film (irradiated surface), 9
0: Reference illuminometer (fifth optical sensor), 100: Mask alignment system (alignment system), 104R, 104L
... Imaging element (seventh optical sensor), LB ... Laser beam (energy beam), R ... Reticle (mask), W ... Wafer (substrate), Q1 ... Schottky electrode, IL ... Exposure light (energy beam), PL ... Projection optical system.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroaki Ogawa 4-3 Ikejiri, Itami-shi, Hyogo Mitsubishi Cable Industries, Ltd. Itami Works (72) Inventor Yoichiro Ouchi 4-3-3 Ikejiri, Itami-shi, Hyogo Mitsubishi Electric Wire Inside the Itami Works of Industrial Co., Ltd. (72) Masahiro Koto 4-3-1 Ikejiri, Itami-shi, Hyogo Mitsubishi Cable Industries Inside Itami Works, Ltd. (72) Inventor Kazumasa Hiramatsu 1-4-4-2 Shibata, Yokkaichi-shi, Mie Prefecture ( 72) Inventor Jin Takeuchi 3-2-3 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation (72) Inventor Hiroshi Hamamura 3-2-3 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation (72) Inventor Tatsushi Nomura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term in Nikon Corporation (reference) 2F065 AA03 AA06 AA09 AA20 AA39 BB27 CC20 DD16 EE00 EE05 EE08 FF02 FF04 FF44 FF46 FF51 FF61 GG03 GG04 GG08 GG17 GG22 HH04 HH05 HH13 HH14 HH15 JJ01 JJ03 JJ05 NN09 LL26 LL12 LL12 LL12 LL12 LL12 LL12 LL12 QQ12 QQ13 QQ17 QQ23 QQ25 QQ26 QQ27 QQ28 QQ41 QQ42 5F046 BA04 BA05 CA04 CA08 CB02 CB10 CB12 CB13 CC03 CC04 DA02 DB01 DB14 DC01 DC02 DC12 ED01 FA16 FB04 FB08 FB12

Claims (28)

[Claims] Illuminating a mask with an energy beam;
An exposure apparatus for transferring a pattern formed on the mask onto a substrate, comprising: a light source that outputs the energy beam; and a light receiving surface that is provided inside a housing of the light source and receives the energy beam. A light-receiving layer made of a GaN-based semiconductor of the first conductivity type provided on the side, and a Schottky electrode provided on the light-receiving surface; and a region of the light-receiving surface covered with the Schottky electrode. A first optical sensor having a Schottky barrier type semiconductor light receiving element having a total length of a boundary line with an exposed region longer than an outer peripheral length of the light receiving surface. Illuminating the mask with an energy beam;
An exposure apparatus for transferring a pattern formed on the mask onto a substrate, comprising: a light source for outputting the energy beam; and a light receiving surface provided between the light source and the substrate surface for receiving the energy beam. A light-receiving layer made of a GaN-based semiconductor of the first conductivity type provided on one side thereof; and a Schottky electrode provided on the light-receiving surface, and the light-receiving surface is covered with the Schottky electrode. A second semiconductor light-receiving element having a Schottky barrier type semiconductor light-receiving element in which the total length of the boundary line between the region and the exposed region is longer than the outer peripheral length of the light-receiving surface;
And an optical sensor. 3. The exposure apparatus according to claim 2, wherein the second optical sensor is an integrator sensor used for estimating illuminance on an image plane. 4. The exposure apparatus according to claim 2, wherein the second optical sensor is used to constantly monitor the energy beam. 5. The apparatus according to claim 3, further comprising an exposure amount control device for controlling an exposure amount based on an output of the integrator sensor so that an integrated exposure amount on the substrate becomes a target exposure amount. Exposure apparatus according to the above. 6. A projection optical system for projecting the energy beam emitted from the mask onto the substrate; and when the energy beam from the light source is irradiated from the mask side toward the projection optical system, A light-receiving layer made of a GaN-based semiconductor of a first conductivity type provided with a light-receiving surface for receiving a reflected light beam from at least one of the substrate and the mask, and a Schottky electrode provided on the light-receiving surface; Wherein the sum of the lengths of the boundary lines between the area covered with the Schottky electrode and the exposed area of the light receiving surface is longer than the outer peripheral length of the light receiving surface. And a third optical sensor having the semiconductor light receiving element. 7. A method of calculating a reflectance of the substrate based on an output of the integrator sensor and an output of the third optical sensor, and irradiating the projection optical system with the energy beam based on an output of the integrator sensor. A calculating device for calculating an amount; and an imaging characteristic adjusting device for adjusting an imaging characteristic of the projection optical system based on the reflectance and the irradiation amount calculated by the calculating device. The exposure apparatus according to claim 6, wherein 8. A projection optical system for projecting the energy beam emitted from the mask onto the substrate; a substrate stage that holds the substrate and moves at least two-dimensionally; A fourth optical sensor for receiving the energy beam applied to at least a part of the illumination field, and using the fourth optical sensor to determine the transmittance of the optical system including the projection optical system at a predetermined interval; And a transmittance measuring device for measuring the exposure amount, wherein the exposure amount control device controls the exposure amount further considering the fluctuation of the transmittance measured by the transmittance measuring device. An exposure apparatus according to claim 5. 9. A light-receiving layer comprising a first-conductivity-type GaN-based semiconductor provided on one side with a light-receiving surface for receiving the energy beam via the projection optical system, the fourth light sensor comprising: A Schottky electrode provided on the light-receiving surface, wherein the sum of the lengths of the boundaries between the area covered with the Schottky electrode and the exposed area of the light-receiving surface is the light-receiving surface. 9. The exposure apparatus according to claim 8, further comprising a Schottky barrier type semiconductor light receiving element longer than the outer circumference of the semiconductor light receiving element. 10. An exposure apparatus for illuminating a mask with an energy beam and transferring a pattern formed on the mask onto a substrate, wherein the substrate stage holds the substrate and moves at least two-dimensionally; A light-receiving layer made of a GaN-based semiconductor of the first conductivity type, provided on one side of the light-receiving surface for receiving the energy beam irradiated on at least a part of a predetermined illumination field; A Schottky electrode provided on the surface, and the sum of the lengths of the boundary lines between the area covered with the Schottky electrode and the exposed area in the light receiving surface is the outer circumference of the light receiving surface. A fifth optical sensor having a Schottky barrier type semiconductor light receiving element longer than the length of the semiconductor light receiving element. 11. A projection optical system for projecting the energy beam emitted from the mask onto the substrate, wherein the fifth optical sensor is configured to detect an energy beam from a mark arranged on an object plane side of the projection optical system. The exposure apparatus according to claim 10, wherein the sensor is a sensor that receives light on an image plane side of the projection optical system. 12. A projection optical system for projecting the energy beam emitted from the mask onto the substrate, wherein the fifth optical sensor is used for measuring transmittance of an optical system including the projection optical system. The exposure apparatus according to claim 10, wherein the exposure apparatus is a sensor. 13. A projection optical system for projecting the energy beam emitted from the mask onto the substrate, wherein the fifth optical sensor applies the energy beam to the entire illumination field at one degree. 11. An irradiation amount monitor having the light receiving surface having an area capable of receiving light.
3. The exposure apparatus according to claim 1. 14. A projection optical system for projecting the energy beam emitted from the mask onto the substrate, wherein the fifth optical sensor is detachably mounted on the substrate stage, Having the light receiving layer to receive interference light of the energy beam irradiated to at least a part thereof and a light beam emitted from a predetermined pinhole,
The exposure apparatus according to claim 10, wherein the exposure apparatus is a sensor used to measure an imaging characteristic of the projection optical system. 15. The exposure according to claim 13, further comprising an imaging characteristic adjusting device that adjusts an imaging characteristic of the projection optical system based on a measurement value of the fifth optical sensor. apparatus. 16. The exposure apparatus according to claim 10, wherein the fifth optical sensor is a reference illuminometer detachably mounted on the substrate stage. 17. The exposure apparatus according to claim 16, wherein the reference illuminometer is used for calibrating an exposure amount on a substrate between a plurality of exposure apparatuses. 18. The exposure apparatus according to claim 10, wherein the fifth optical sensor is a sensor that can measure an in-plane illuminance in a predetermined illumination field. 19. An exposure apparatus for illuminating a mask with an energy beam and transferring a pattern formed on the mask onto a substrate via a projection optical system, comprising: a light source for outputting the energy beam; A substrate stage that holds and moves at least two-dimensionally; a light receiving surface that is provided on the substrate stage and receives the energy beam from the light source that has passed through a predetermined opening formed in the light receiving surface A light-receiving layer made of a GaN-based semiconductor of the first conductivity type, the surface of which is provided on one side thereof; and a Schottky electrode provided on the light-receiving surface, wherein the light-receiving surface is covered with the Schottky electrode. A total length of the boundary line between the exposed region and the exposed region has a Schottky barrier type semiconductor light receiving element longer than the outer peripheral length of the light receiving surface, and is formed on the mask. A sixth optical sensor used for detecting information for determining a positional relationship between the mask and the substrate with a maximum of six degrees of freedom by relatively scanning the image of the measured pattern and the opening. An exposure apparatus comprising: 20. An exposure apparatus for illuminating a mask with an energy beam and transferring a pattern formed on the mask onto a substrate via a projection optical system, wherein the substrate moves at least two-dimensionally while holding the substrate. A stage for detecting a mark pattern present in a predetermined illumination field on the mask and a predetermined mark pattern correspondingly present on the substrate stage;
An alignment system having an optical sensor of the first type, wherein the seventh optical sensor has a light receiving surface for receiving image light fluxes of the both mark patterns on one side thereof, and a light receiving surface made of a GaN-based semiconductor of the first conductivity type. Layer, including a Schottky electrode provided on the light receiving surface, of the light receiving surface, the sum of the length of the boundary line between the region covered with the Schottky electrode and the exposed region, An exposure apparatus comprising: a Schottky barrier type semiconductor light receiving element longer than the outer circumference of the light receiving surface. 21. An image sensor for detecting a projected image of each of the mark patterns as a predetermined two-dimensional image, wherein the seventh optical sensor is a mask alignment system for performing mask alignment. 21. The exposure apparatus according to claim 20, wherein 22. The apparatus further comprising one or more eighth optical sensors for receiving the energy beam, wherein at least one of the eighth optical sensors has a light receiving surface for receiving the energy beam on one side thereof. A light-receiving layer made of a GaN-based semiconductor of the first conductivity type provided on the light-receiving surface, and a Schottky electrode provided on the light-receiving surface. 3. An optical sensor having a Schottky barrier type semiconductor light receiving element having a total length of a boundary line with a region where the light receiving surface is longer than an outer peripheral length of the light receiving surface. 21. The exposure apparatus according to any one of 10, 19, and 20. 23. The exposure apparatus according to claim 8, wherein the substrate stage is capable of controlling the position and orientation of the substrate in at least six degrees of freedom. 24. The energy beam has a wavelength of 300 n.
The exposure apparatus according to any one of claims 1 to 23, wherein m is equal to or less than m. 25. An exposure method for illuminating a mask with an energy beam and transferring a pattern formed on the mask onto a substrate via a projection optical system, wherein the light receiving surface is provided on one side thereof. A photocurrent that is made of a conductive type GaN-based semiconductor and receives the energy beam in a state where a reverse bias is applied to a light receiving unit provided with at least a Schottky electrode on the light receiving surface, and a photocurrent extracted to the outside from the light receiving unit And a second step of transferring the pattern of the mask onto the substrate at a predetermined resolution and depth of focus using the detected information. Exposure method. 26. The information detected in the first step is adjusted in an image forming characteristic of the projection optical system in the second step.
3. The method according to claim 2, wherein the control unit is used for at least one of controlling an exposure amount and adjusting a relative position between the mask and the substrate.
6. The exposure method according to 5. 27. A light source device used in an exposure apparatus that illuminates a mask with an energy beam and transfers a pattern formed on the mask onto a substrate, wherein the beam source outputs the energy beam; and the beam source. A light-receiving layer made of a first conductivity type GaN-based semiconductor, the light-receiving surface receiving the energy beam output from the beam source being provided on one side thereof; and a light-receiving layer provided on the light-receiving surface. And the total length of the boundary line between the area covered with the Schottky electrode and the exposed area of the light receiving surface is greater than the outer peripheral length of the light receiving surface. A light sensor having a long Schottky barrier type semiconductor light receiving element. 28. A device manufacturing method including a photolithography step, wherein in the photolithography step, exposure is performed using the exposure apparatus according to claim 24.