JP2005026461A - Telecentricity adjusting method of image observing apparatus, focusing position measuring method thereof, exposure apparatus and focusing position measuring method of projection optical system including image observing apparatus adjusted and measured therewith adjusting method or measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the telecentricity adjusting method of an image observing apparatus which can adjust, with higher accuracy, telecentricity of an image observing apparatus using a low price tool. <P>SOLUTION: In this telecentricity adjusting method of the image observing apparatus, the image of an observation object is formed on the imaging surface of an imaging element 28 on the basis of the light from the observation object via an objective optical system 22 by guiding the light to the observation object from the predetermined secondary light source 10b. This adjusting method comprises a secondary light source image forming process to form the image of the predetermined secondary light source on the predetermined surface on the basis of the light from the predetermined secondary light source 10b via the objective optical system 22, an image focusing aperture iris image forming process to form an image of the image focusing aperture iris 20 applicated between the objective optical system 22 and the imaging element 28 to the predetermined surface on the basis of the light from the predetermined secondary light source 10b via the objective optical system 22, and an adjusting process to adjust the location of the predetermined secondary light source 10b on the basis of both images of the secondary light source and the image focusing aperture iris. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a telecentricity adjustment method for an image observation apparatus that adjusts telecentricity of an image observation apparatus, a focus position measurement method for an image observation apparatus that measures a focus position of the image observation apparatus, the adjustment method, or the measurement The present invention relates to an exposure apparatus having an image observation apparatus adjusted or measured by the method, and a focus position measuring method of a projection optical system for measuring a focus position of the projection optical system.
[0002]
[Prior art]
In the manufacturing process of semiconductor elements, liquid crystal display elements, and other micro devices, an exposure apparatus that projects and exposes a pattern, which is an original image formed on a mask, onto a photosensitive substrate coated with a photosensitive agent such as a photoresist (for example, Step-and-repeat type exposure apparatus) is used. Here, the exposure apparatus includes an image observation apparatus for performing alignment (alignment) between the mask and the photosensitive substrate in order to perform overlay exposure. The accuracy of alignment by this image observing apparatus is required to be high with the miniaturization of the pattern, and the exposure apparatus has an alignment of about a fraction of the minimum line width of the pattern or about several tenths. An image observation apparatus having the accuracy of 2 is provided.
[0003]
As the above-described image observation apparatus, an FIA (Field Image) that measures the position of an alignment mark by performing image processing on image data of the alignment mark that is illuminated and picked up by light having a wide wavelength bandwidth emitted from a light source such as a halogen lamp. Alignment microscope is present. Also, in order to measure the focus position and mask position of the FIA microscope with respect to the substrate stage on which the photosensitive substrate is placed, so-called baseline measurement, a CCD is embedded in the substrate stage, and the position of the photosensitive substrate surface is imaged by the CCD. There is an AIS (Aerial Image Sensor) equipped with a relay lens system for enlarging and projecting onto a surface.
[0004]
FIG. 28 is a diagram showing the configuration of the FIA microscope. The FIA microscope includes a light source 200, and light emitted from the light source 200 becomes parallel light by passing through the collector lens 202, and becomes light in a desired wavelength range by passing through the wavelength selection filter 204, and is emitted by the condenser lens 206. The light is condensed on the incident end 208 a of the guide 208. Light emitted from the exit end 208 b of the light guide 208 enters the half mirror 212 via the condenser lens 210. The illumination light reflected by the half mirror 212 illuminates the object 216 placed at the focal position of the first objective lens 214 through the first objective lens 214. At this time, the illumination light that illuminates the object 216 is so-called Koehler illumination in order to uniformly illuminate the object 216, and the condenser lens 210 so that the exit end 208 b of the light guide 208 is at infinity on the object 216. As a result, an image of the exit end 208 b of the light guide 208 is formed in the vicinity of the rear focal position of the first objective lens 214. The reflected light reflected by the object 216 becomes parallel light by the first objective lens 214, passes through the half mirror 212, forms an image on the imaging surface of the CCD 220 through the second objective lens 218, and forms an object on the CCD 220. The position of the object 216 is measured by image processing the image. The FIA microscope is disclosed in Patent Document 1 and the like.
[0005]
The FIA microscope described above includes an aperture stop 222 in the vicinity of the rear focal position of the first objective lens 214 in order to prevent a change in magnification or a positional shift caused by defocusing of the object and to measure the position of the object 216 with high accuracy. The object surface side is configured to be telecentric. Further, this FIA microscope is used with respect to the focal plane of the projection optical system of the exposure apparatus in order to minimize the amount of movement of the substrate stage in the optical axis direction of the exposure apparatus during exposure and measurement of the position measurement mark. The focus position of the FIA microscope is adjusted so as to approximately match. In addition, in a liquid crystal exposure apparatus that exposes a large photosensitive substrate, a plurality of FIA microscopes may be mounted to simultaneously measure position measurement marks formed at a plurality of locations on the photosensitive substrate. . In order to perform measurement simultaneously with the plurality of FIA microscopes, it is necessary to adjust the focal position of the FIA microscope with high accuracy.
[0006]
As a telecentricity adjustment method for an FIA microscope, the substrate stage is moved in the normal direction of the substrate stage with the FIA microscope mounted on the exposure apparatus, and the substrate stage (or the photosensitive substrate placed on the substrate stage) There is a method for measuring and adjusting the position of the mark formed thereon. That is, the amount of movement in the normal direction of the substrate stage of the exposure apparatus is ΔZ, the amount of mark position movement is Δr, the amount of telecentricity is a (= Δr / ΔZ), and the light source of the FIA microscope is set so that a is within a predetermined value. Adjust the position or σ aperture position conjugate with the light source.
[0007]
As a method for measuring the focus position of the FIA microscope, the substrate stage is moved in the normal direction of the substrate stage with the FIA microscope mounted on the exposure apparatus, and the spatial image intensity distribution of the marks formed on the substrate stage is used. There is a contrast method for measuring the focus position. That is, the differential peak value is obtained from the aerial image intensity distribution of the mark, the normal direction moving position of the substrate stage at which the differential peak value becomes the highest is measured, and the focus position of the FIA microscope is measured based on the measured value.
[0008]
In addition, as a method for measuring the baseline of the FIA microscope using the above-mentioned AIS, an index image projected by the FIA optical system is formed in the FIA microscope so as to form an image at a position corresponding to the surface of the photosensitive substrate. In addition, there is a method of measuring by the AIS based on the CCD center of the AIS, and a method of measuring the position of the AIS index provided in the vicinity of the photosensitive substrate surface by the CCD of the FIA microscope. When providing an index on the AIS side, since the position of the index is fixed with respect to the AIS, it is necessary to accurately match the focus position of the AIS and the position of the index when the AIS is mounted on the exposure apparatus. .
[0009]
When performing exposure for creating a color filter, the illumination wavelength of the FIA microscope may be switched corresponding to each of RGB. In this case, the focus position is adjusted by a predetermined standard illumination wavelength, and the focus position for each illumination wavelength is obtained in advance by measurement. When switching the illumination wavelength, the substrate stage is moved to the focus position of the illumination wavelength measured in advance, and the position measurement mark position is measured.
[0010]
As a method for measuring the focus position of the projection optical system, an index is placed at the focal position of the AIS, the position of the index plane in the optical axis direction of the projection optical system is measured by autofocus, and the projection optical system places it on the index. There is a method in which the imaged mask pattern is imaged again on the imaging surface of the CCD by an AIS relay lens and the contrast is measured by the aerial image intensity distribution. That is, the aerial image intensity distribution is measured by sequentially moving the substrate stage in the direction of the optical axis, and the measurement position by autofocus on the index plane when the contrast reaches a peak is detected as the focus position of the projection optical system.
[0011]
As a method for measuring distortion of the projection optical system, the position of the mask pattern projected by the projection optical system is measured with reference to the index position of the AIS, and the substrate stage is placed in a plane perpendicular to the optical axis. There is a method for measuring the distortion of the projection optical system by moving and measuring the pattern projection position of the entire exposure area in the same manner.
[0012]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-214047
[0013]
[Problems to be solved by the invention]
Incidentally, the telecentricity adjustment and the focus position measurement of the FIA microscope are performed in a state where the FIA microscope is mounted on the exposure apparatus. However, in order to measure the focus position of the FIA microscope with high accuracy, it is necessary to measure the focus position by finely adjusting the pitch in the direction of the optical axis in the depth of focus or higher range, which requires an enormous amount of time. .
[0014]
In addition, since the substrate size has increased in recent years, errors in the position in the optical axis direction during measurement of the focus position, such as leveling errors in the substrate stage and waviness in the photosensitive substrate, tend to increase. The accuracy of the city and focus position greatly affects the exposure accuracy of the exposure apparatus. However, in order to perform telecentricity measurement and focus position measurement with high accuracy, the driving amount of the substrate stage of the exposure apparatus in the optical axis direction and the stroke of the measurement system for detecting the optical axis position are expanded. As a result, it becomes a factor of cost increase. Also, in order to measure the telecentricity and the focus position with high accuracy before mounting on the exposure apparatus by assembling and adjusting the FIA microscope in units, exposure is performed as a tool for adjusting the FIA microscope. Since the driving mechanism in the optical axis direction of the apparatus and the measurement system for detecting the position in the optical axis direction are required, it is necessary to use an expensive one.
[0015]
In the method of measuring the position of the AIS index provided in the vicinity of the photosensitive substrate surface, which is one of the methods for measuring the focus position of the FIA microscope, using the CCD of the FIA microscope, the index is set on the exposure apparatus. There is no mechanism for moving the lens up and down with respect to the AIS, and there is a disadvantage that the focus can be adjusted only by visual confirmation even when adjusting the focus position of the FIA microscope.
[0016]
Also in the measurement of the focus position of the projection optical system, if the index position is deviated by ΔZ from the AIS focal plane, the position detected as the focal plane of the projection optical system is deviated by ΔZ from the actual focus position of the projection optical system. End up.
[0017]
Further, when the index position is deviated by ΔZ from the AIS focal plane, the index position measured by the AIS system is not used when the index illumination light is not telecentric, that is, when the projection optical system is not telecentric (a telecentricity amount a). Is shifted by ΔZ × a. For this reason, in distortion measurement of a projection optical system that performs measurement using the index position as a reference, if the telecentricity in the exposure area plane is not uniform, the reference index position varies depending on the measurement location. An error occurs in the distortion measurement value.
[0018]
An object of the present invention is to provide a telecentricity adjustment method for an image observation apparatus that can adjust the telecentricity of the image observation apparatus with high accuracy using an inexpensive tool, and to adjust the focus position of the image observation apparatus with high accuracy using an inexpensive tool. A focus position measuring method of an image observation apparatus capable of measuring, an exposure apparatus having an image observation apparatus adjusted or measured by the adjustment method or the measurement method, and a projection capable of easily performing a focus position measurement of a projection optical system To provide a focus position measuring method for an optical system.
[0019]
[Means for Solving the Problems]
The telecentricity adjustment method for an image observation apparatus according to claim 1, wherein light from a predetermined secondary light source is guided to an observation object, and based on the light from the observation object via an objective optical system, In the telecentricity adjustment method for an image observation apparatus that forms an image of the observation object on an imaging surface, the predetermined secondary light source is based on light from the predetermined secondary light source via the objective optical system. A secondary light source image forming step for forming the image on a predetermined surface and light from the predetermined secondary light source via the objective optical system, and disposed between the objective optical system and the imaging device. An imaging aperture stop image forming step of forming an image of the imaging aperture stop on the predetermined surface, and the predetermined secondary light source based on both the image of the secondary light source and the image of the imaging aperture stop. And an adjusting step for adjusting the position.
[0020]
According to the telecentricity adjustment method for an image observation apparatus according to claim 1, the position of the secondary light source is adjusted based on the secondary light source and the imaging aperture stop image formed on the predetermined surface. Perform telecentricity adjustment. That is, the telecentricity adjustment can be performed by a simple method before the image observation apparatus is mounted on the exposure apparatus. Therefore, the cost for adjusting the telecentricity of the image observation apparatus can be reduced, and the telecentricity adjustment of the image observation apparatus can be performed easily and with high accuracy.
[0021]
The telecentricity adjustment method of the image observation apparatus according to claim 2, wherein an imaging surface of an imaging device different from the imaging device is disposed on the predetermined surface, and the image of the secondary light source and the imaging aperture stop The imaging aperture stop image forming step is based on light from the predetermined secondary light source via both the imaging aperture stop and the objective optical system. Forming an image of the imaging aperture stop, and in the adjusting step, based on the image of the secondary light source and the image of the imaging aperture stop taken in the imaging step, the position of the secondary light source It is characterized by adjusting.
[0022]
According to the telecentricity adjustment method of the image observation apparatus according to claim 2, the image is picked up by the image pickup device using a simple and inexpensive tool such as an image pickup device for performing the telecentricity adjustment of the image observation device. The telecentricity adjustment of the image observation apparatus is performed by adjusting the position of the secondary light source based on the image of the secondary light source and the image of the imaging aperture stop. That is, before the image observation apparatus is mounted on the exposure apparatus, the telecentricity adjustment of the image observation apparatus can be performed by a simple method. Therefore, the cost for adjusting the telecentricity of the image observation apparatus can be reduced, and the telecentricity adjustment of the image observation apparatus can be performed easily and with high accuracy.
[0023]
The telecentricity adjustment method for an image observation apparatus according to claim 3 includes a tool optical system arranging step of arranging a tool optical system in an optical path between the objective optical system and the imaging device, and the tool optical system. An imaging surface arrangement step of positioning the imaging surface of the imaging element at a focal position of the imaging element, an image of the secondary light source, and an image of an imaging aperture stop disposed between the objective optical system and the imaging element; An imaging step of imaging using the imaging element, and in the adjustment step, the secondary light source is based on the image of the secondary light source and the image of the imaging aperture stop imaged in the imaging step. The position of is adjusted.
[0024]
According to the telecentricity adjustment method for an image observation apparatus according to the third aspect, a simple and inexpensive tool optical system for adjusting the telecentricity of the image observation apparatus is used, and the image is picked up by the image pickup device of the image observation apparatus. The telecentricity adjustment of the image observation apparatus is performed by adjusting the position of the secondary light source based on the image of the secondary light source and the image of the imaging aperture stop. That is, before the image observation apparatus is mounted on the exposure apparatus, the telecentricity adjustment of the image observation apparatus can be performed by a simple method. Therefore, the cost for adjusting the telecentricity of the image observation apparatus can be reduced, and the telecentricity adjustment of the image observation apparatus can be performed easily and with high accuracy.
[0025]
The telecentricity adjustment method for an image observation apparatus according to claim 4, wherein the image of the predetermined secondary light source and the image of the imaging aperture stop are formed on the predetermined surface. The method further includes a step of moving the position along the optical axis direction.
[0026]
According to the telecentricity adjustment method of the image observation apparatus according to claim 4, the image of the secondary light source and the image of the imaging aperture stop are displayed on the predetermined surface by moving the position of the secondary light source along the optical axis direction. Form simultaneously on top. Further, the telecentricity adjustment of the image observation apparatus is performed by adjusting the position of the secondary light source based on the image of the secondary light source and the imaged aperture stop image formed at the same time. Therefore, before the image observation apparatus is mounted on the exposure apparatus, the telecentricity adjustment of the image observation apparatus can be performed with high accuracy by a simple method.
[0027]
The telecentricity adjustment method for an image observation apparatus according to claim 5 further includes a step of inserting a diffusion plate in an optical path between the predetermined secondary light source and the imaging aperture stop. To do.
[0028]
According to the telecentricity adjustment method of the image observation apparatus according to claim 5, an image and an image of the secondary light source are formed by inserting a diffusion plate in the optical path between the secondary light source and the imaging aperture stop. An aperture stop image is simultaneously formed on a predetermined surface. Further, the telecentricity adjustment of the image observation apparatus is performed by adjusting the position of the secondary light source based on the image of the secondary light source and the imaged aperture stop image formed at the same time. Therefore, before the image observation apparatus is mounted on the exposure apparatus, the telecentricity adjustment of the image observation apparatus can be performed with high accuracy by a simple method.
[0029]
The telecentricity adjustment method for an image observation apparatus according to claim 6 is characterized in that the diffusivity of the diffusion plate is determined so that an image of the secondary light source can be discriminated on the predetermined plane. To do.
[0030]
According to the telecentricity adjustment method of the image observation apparatus according to claim 6, since the diffusivity of the diffusion plate is determined so that the image of the secondary light source can be determined on the predetermined surface, the image of the secondary light source And an image of the imaging aperture stop can be simultaneously formed on a predetermined plane. Further, the telecentricity adjustment of the image observation apparatus can be performed based on the image of the secondary light source and the imaging aperture stop image formed at the same time. Therefore, before the image observation apparatus is mounted on the exposure apparatus, the telecentricity adjustment of the image observation apparatus can be performed with high accuracy by a simple method.
[0031]
The telecentricity adjustment method for an image observation apparatus according to claim 7, wherein the adjustment step is performed such that the image of the predetermined secondary light source and the image of the imaging aperture stop are concentric. The position of the secondary light source is adjusted.
[0032]
According to the telecentricity adjustment method of the image observation apparatus according to claim 7, the position of the secondary light source is adjusted so that the simultaneously formed image of the secondary light source and the image of the imaging aperture stop are concentric. By doing so, the telecentricity adjustment of the image observation apparatus can be performed. That is, the telecentricity adjustment of the image observation apparatus can be performed with high accuracy by a simple method before the image observation apparatus is mounted on the exposure apparatus.
[0033]
The telecentricity adjustment method for an image observation apparatus according to claim 8, wherein the adjustment step includes a position of a light guide end surface for forming the predetermined secondary light source based on light from a light source, or the predetermined The position of the illumination σ stop for forming the secondary light source is adjusted.
[0034]
According to the telecentricity adjustment method of the image observation apparatus according to claim 8, the position of the light guide end face for forming the secondary light source based on the light from the light source, or the illumination for forming the secondary light source By adjusting the position of the σ stop, the optical system of the image observation apparatus can be a telecentric optical system. That is, the telecentricity adjustment of the image observation apparatus can be performed with high accuracy by a simple method before the image observation apparatus is mounted on the exposure apparatus.
[0035]
Further, the focus position measuring method of the image observation apparatus according to claim 9, wherein light from a predetermined secondary light source is guided to an observation object, and an image sensor is based on light from the observation object via an objective optical system In the focus position measurement method of the image observation apparatus for forming an image of the observation object on the imaging surface of the illumination observation light eccentricity, the predetermined secondary light source is decentered in a predetermined eccentric direction with respect to the optical axis of the image observation apparatus And a linear pattern extending in a direction perpendicular to the eccentric direction in the vicinity of the surface (including the surface on which the observation object is disposed) or the surface on which the observation object is disposed A pattern placement step for positioning in the vicinity of a conjugate plane (including a plane conjugate with the placed plane), an aerial image intensity distribution measurement step for measuring an aerial image intensity distribution of the linear pattern, and the aerial image intensity Measured in the distribution measurement process On the basis of the asymmetry of the aerial image intensity distributions, wherein said including the focus measuring step of measuring the focus position of the objective optical system.
[0036]
According to the focus position measuring method of the image observation apparatus according to claim 9, the aerial image intensity distribution of the linear pattern is measured using the linear pattern, and based on the asymmetry of the measured aerial image intensity distribution. Then, the focus position of the image observation apparatus is measured. That is, the focus position can be measured by a simple method before the image observation apparatus is mounted on the exposure apparatus. Therefore, the time and cost for measuring the focus position of the image observation apparatus can be reduced, and the focus position measurement of the image observation apparatus can be performed easily and with high accuracy. Note that, when a mirror is interposed between the secondary light source and the linear pattern in the eccentric direction of the illumination light, the influence of bending of the optical path of the illumination light by the mirror is also considered.
[0037]
The focus position measurement method of the image observation apparatus according to claim 10 further includes an image position measurement step of measuring an image position of the linear pattern, wherein the focus position measurement step is performed in the aerial image intensity distribution measurement step. The focus position of the objective lens is measured based on the asymmetry of the measured aerial image intensity distribution and the image position of the linear pattern measured in the image position measuring step.
[0038]
According to the focus position measurement method of the image observation apparatus according to claim 10, in addition to focus position measurement based on asymmetry of the aerial image intensity distribution of the linear pattern, the image position of the linear pattern is measured and measured. The focus position is measured based on the image position of the linear pattern. That is, the focus position of the image observation apparatus can be measured easily and with extremely high accuracy before the image observation apparatus is mounted on the exposure apparatus.
[0039]
According to another aspect of the present invention, there is provided a focus position measuring method for guiding the light from a predetermined secondary light source to an observation object, and an imaging device based on the light from the observation object via an objective optical system. In the focus measurement method of the image observation apparatus that forms the image of the observation object on the imaging surface of the illumination observation light, the illumination light eccentric step of decentering the predetermined secondary light source in a predetermined eccentric direction with respect to the optical axis of the image observation apparatus And a linear pattern extending in a direction perpendicular to the eccentric direction in the vicinity of the surface (including the surface on which the observation object is disposed) or the surface on which the observation object is disposed. A pattern placement step for positioning in the vicinity of a plane (including a plane conjugate with the surface to be placed), a measurement step for measuring the image position of the linear pattern, and the linear shape measured in the measurement step Based on pattern image position , Characterized in that it comprises a focus measuring step of measuring the focus position of the objective optical system.
[0040]
According to the focus position measuring method of the image observation apparatus according to claim 11, the image position of the linear pattern is measured using the linear pattern, and the image observation is performed based on the measured image position of the linear pattern. The focus position of the device is measured. That is, the focus position can be measured by a simple method before the image observation apparatus is mounted on the exposure apparatus. Therefore, it is possible to reduce the time and cost for measuring the focus position of the image observation apparatus, and it is possible to easily and accurately perform the focus position measurement of the image observation apparatus.
[0041]
The focus position measuring method of the image observation apparatus according to claim 12, wherein the illumination light eccentric step includes a position of a light guide end surface for forming the predetermined secondary light source based on light from a light source, or the A step of decentering the position of the illumination σ stop for forming the predetermined secondary light source along the decentering direction.
[0042]
According to the focus position measuring method of the image observation apparatus according to claim 12, the position of the light guide end surface for forming the secondary light source or the position of the illumination σ stop for forming the secondary light source is decentered. Thus, the secondary light source can be easily decentered. Therefore, it is possible to easily and accurately measure the focus position of the image observation apparatus before mounting the image observation apparatus on the exposure apparatus.
[0043]
The focus position measuring method of the image observation apparatus according to claim 13, wherein the illumination light eccentric step further includes a step of replacing an illumination σ stop for forming the predetermined secondary light source. .
[0044]
According to the focus position measuring method of the image observation apparatus of the thirteenth aspect, the image of the secondary light source can be easily formed on the imaging surface of the image sensor by exchanging the illumination σ stop. Therefore, it is possible to easily and accurately measure the focus position of the image observation apparatus before mounting the image observation apparatus on the exposure apparatus.
[0045]
The focus position measurement method for an image observation apparatus according to claim 14 is characterized in that the linear pattern is a phase pattern.
[0046]
According to the focus position measuring method of the image observation apparatus according to claim 14, the phase pattern is used to measure the light intensity of the phase pattern image, and based on the asymmetry of the measured light intensity of the phase pattern image. The focus position of the image observation apparatus is measured. That is, the focus position can be measured by a simple method before the image observation apparatus is mounted on the exposure apparatus. Therefore, it is possible to reduce the time and cost for measuring the focus position of the image observation apparatus, and it is possible to easily and accurately perform the focus position measurement of the image observation apparatus.
[0047]
An exposure apparatus according to a fifteenth aspect includes an image observation apparatus that performs telecentricity adjustment by the telecentricity adjustment method according to any one of the first to eighth aspects. .
[0048]
According to the exposure apparatus of the fifteenth aspect, the image observation apparatus in which the telecentricity adjustment is performed precisely is provided. Therefore, since the mask and the photosensitive substrate are aligned based on the position of the photosensitive substrate accurately measured by this image observation apparatus, a fine exposure pattern can be satisfactorily exposed.
[0049]
An exposure apparatus according to a sixteenth aspect includes an image observation apparatus that measures a focus position by the focus position measurement method according to any one of the ninth to fourteenth aspects.
[0050]
According to the exposure apparatus of the sixteenth aspect, the image observation apparatus in which the focus position measurement is precisely performed is provided. Therefore, since the photosensitive substrate is placed at the focus position accurately measured by the image observation apparatus and exposure is performed, a fine exposure pattern can be satisfactorily exposed.
[0051]
The focus position measurement method for a projection optical system according to claim 17, wherein the focus of the projection optical system projects a pattern image formed on a mask disposed on the first surface onto a photosensitive substrate disposed on the second surface. In the position measurement method, an illumination light decentering step for decentering a predetermined secondary light source in a predetermined decentering direction with respect to the optical axis of the projection optical system, and the light from the decentered secondary light source on the first surface And an illumination process that leads to a linear pattern extending in a direction perpendicular to the eccentric direction (including the first surface) or near a surface conjugate with the first surface (the first (Including a plane conjugate with one surface), an aerial image intensity distribution measuring step for measuring an aerial image intensity distribution of the linear pattern, and the aerial image intensity distribution measuring step. Based on asymmetry of aerial image intensity distribution There are, characterized in that it comprises a focus measuring step of measuring the focus position of the projection optical system.
[0052]
According to the focus position measuring method for a projection optical system according to claim 17, a linear pattern is used to measure the aerial image intensity distribution of the linear pattern, and based on the asymmetry of the measured aerial image intensity distribution. The focus position of the projection optical system is measured. Therefore, it is possible to reduce time and cost for measuring the focus position of the projection optical system, and it is possible to easily and accurately measure the focus position of the projection optical system.
[0053]
The focus position measurement method for a projection optical system according to claim 18 further includes an image position measurement step of measuring an image position of the linear pattern, wherein the focus position measurement step includes the aerial image intensity distribution measurement step. The focus position of the projection optical system is measured based on the asymmetry of the measured aerial image intensity distribution and the image position of the linear pattern measured in the image position measuring step.
[0054]
According to the focus position measuring method of the projection optical system according to claim 18, in addition to the focus position measurement based on the asymmetry of the aerial image intensity distribution of the linear pattern, the image position of the linear pattern is measured and measured. The focus position is measured based on the image position of the linear pattern. Therefore, the focus position measurement of the projection optical system can be performed easily and with extremely high accuracy.
[0055]
The focus position measuring method for a projection optical system according to claim 19 is the focus of the projection optical system for projecting the pattern image formed on the mask arranged on the first surface onto the photosensitive substrate arranged on the second surface. In the position measurement method, an illumination light decentering step for decentering a predetermined secondary light source in a predetermined decentering direction with respect to the optical axis of the projection optical system, and the light from the decentered secondary light source on the first surface And an illumination process that leads to a linear pattern extending in a direction perpendicular to the eccentric direction (including the first surface) or near a surface conjugate with the first surface (the first (Including a plane conjugate with one surface), a measurement step for measuring the image position of the linear pattern, and an image position of the linear pattern measured in the measurement step, The focus position of the objective optical system Characterized in that it comprises a focus measuring step of measuring.
[0056]
According to the focus position measurement method for a projection optical system according to claim 19, a linear pattern is used, an image position of the linear pattern is measured, and projection optical is determined based on the measured image position of the linear pattern. Measure the focus position of the system. Therefore, it is possible to reduce time and cost for measuring the focus position of the projection optical system, and it is possible to easily and accurately measure the focus position of the projection optical system.
[0057]
The exposure method of the present invention is characterized in that a predetermined pattern on a mask is exposed onto a photosensitive substrate using the exposure apparatus according to claim 15 or claim 16. According to this exposure method, exposure is performed using an exposure apparatus including an image observation apparatus in which telecentric adjustment or focus position measurement is accurately performed. Therefore, a fine exposure pattern can be satisfactorily exposed.
[0058]
An exposure method according to the present invention is an image of a predetermined pattern on a mask using a projection optical system in which a focus position is measured by the focus position measurement method according to any one of claims 17 to 19. Is projected and exposed onto a photosensitive substrate. According to this exposure method, since the exposure is performed using the exposure apparatus including the projection optical system in which the focus position is precisely measured, a fine exposure pattern can be satisfactorily exposed.
[0059]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a tool for performing telecentricity adjustment of an FIA microscope and an FIA microscope which are image observation apparatuses.
[0060]
As shown in FIG. 1, the FIA microscope includes a light source 2 made of a halogen lamp. The light beam emitted from the light source 2 disposed at the focal position of the collector lens 4 passes through the collector lens 4 to become parallel light and enters the wavelength selection filter 6. The light in the desired wavelength range that has passed through the wavelength selection filter 6 is condensed at the incident end 10 a of the light guide 10 by the condenser lens 8.
[0061]
The light beam collected at the incident end 10 a of the light guide 10 propagates through the light guide 10 and is emitted from the emission end 10 b of the light guide 10. The light beam from the secondary light source formed at the exit end 10 b of the light guide 10 enters the half mirror 18 through the σ stop 12, the field stop 14, and the condenser lens 16. The light beam reflected by the half mirror 18 passes through the aperture stop 20 and the first objective lens (objective optical system) 22.
[0062]
Here, when the FIA microscope is incorporated in the exposure apparatus and measures the position of the photosensitive substrate (observation object), it is arranged at the focal position of the first objective lens 22 by the light beam that has passed through the first objective lens 22. A position measurement mark (not shown) on the photosensitive substrate is illuminated. The light that illuminates the photosensitive substrate is so-called Koehler illumination in order to uniformly illuminate the photosensitive substrate, and the condenser lens so that the exit end 10b of the light guide 10 is at infinity on the photosensitive substrate. 16, an image of the exit end 10 b of the light guide 10 is formed in the vicinity of the rear focal position of the first objective lens 22. Usually, the image of the exit end 10b of the light guide 10 is smaller than the aperture stop image because the σ value of the σ stop 12 is σ <1. The reflected light reflected by the photosensitive substrate becomes parallel light by the first objective lens 22, passes through the aperture stop 20, the half mirror 18, and the second objective lens 24, is reflected by the reflecting mirror 26, and is a CCD (imaging device). ) An image is formed on the imaging surface 28, and an image of a position measurement mark on the photosensitive substrate is formed. The image formed on the CCD 28 is subjected to image processing, and the position of the photosensitive substrate is measured based on the image processing result.
[0063]
On the other hand, when the telecentricity adjustment of the FIA microscope is performed, the light that has passed through the first objective lens 22 is reflected by the tool mirror 30 for performing the telecentricity adjustment of the FIA microscope and passes through the tool lens 32. Then, the light is incident on a CCD (an image sensor different from the image sensor 28) 34 disposed at the focal position of the tool lens.
[0064]
FIG. 2 is a flowchart showing a telecentricity adjustment method for the FIA microscope according to the first embodiment.
[0065]
First, as shown in FIG. 1, a tool mirror 30, a tool lens 32, and a CCD 34 are arranged below the first objective lens 22 constituting the FIA microscope (step S10). Here, the focal length of the tool lens 32 arranged for performing telecentricity adjustment of the FIA microscope shown in FIG. 1 is based on the focal length and numerical aperture of the first objective lens 22 on the imaging surface of the CCD 34. It is determined so that an aperture stop image of an appropriate size is formed. The imaging surface of the CCD 34 is arranged at the focal position of the tool lens 32.
[0066]
Next, a sigma stop (illumination sigma stop) with a sigma value of 1 or more is prepared and replaced with a sigma stop 12 with a sigma value of 0.7 to 0.9 provided in the FIA microscope (step S11). That is, when the σ value of the σ stop is 0.7 to 0.9, an aperture stop image described later cannot be observed, and only an exit end image of a light guide described later can be observed. On the other hand, when the σ value of the σ stop is 1 or more, the aperture stop image and the light guide exit end image can be observed simultaneously.
[0067]
Next, an aperture stop image (image aperture stop image) and a ride guide exit end (σ stop) image (secondary light source image) are formed (formed) on the imaging surface (predetermined surface) of the CCD 34. In this way, the position of the exit end 10b of the light guide 10 is moved and adjusted along the optical axis direction (step S12). That is, since the FIA microscope has a Kohler illumination arrangement, an aperture stop image and an exit end image of the ride guide are formed on the imaging surface of the CCD 34. In the adjustment in step S12, the aperture stop 20 may be moved in the optical axis direction instead of moving the exit end 10b of the light guide 10 in the optical axis direction.
[0068]
Next, based on the light emitted from the exit end 10 b of the light guide 10 and passing through the σ stop 12, the field stop 14, the condenser lens 16, the aperture stop 20, and the first objective lens 22, an exit end image of the light guide is obtained. It is formed on the imaging surface of the CCD 34 (step S13). Further, based on the light emitted from the exit end 10 b of the light guide 10 and passing through the σ stop 12, the field stop 14, the condenser lens 16, the aperture stop 20, and the first objective lens 22, an aperture stop image is obtained on the imaging surface of the CCD 34. It is formed on top (step S14).
[0069]
Next, both the exit end image of the ride guide formed in step S13 and the aperture stop image formed in step S14 are imaged by the CCD 34 (step S15). Next, based on the exit end image and aperture stop image of the light guide imaged in step S15, the position of the exit end 10b of the light guide 10 or the σ stop 12 is adjusted so that the FIA microscope becomes telecentric (step S15). S16). That is, as shown in FIG. 3, the position of the exit end 10b of the light guide 10 or the σ stop 12 is adjusted so that the aperture stop image 36 and the exit end image 38 of the light guide are concentric. Here, when the aperture stop 20 is fixed and the position of the aperture stop 20 is decentered with respect to the optical axis of the FIA microscope, the aperture stop image 36 and the light guide exit end image 38 are concentric. Even if it adjusts so that it may become, since the aperture stop 20 is decentered, exact telecentricity adjustment is not performed. Therefore, an amount obtained by subtracting the amount of deviation between the optical axis of the FIA microscope and the center of the aperture stop 20 from the amount of deviation between the center of the exit end 10b of the light guide 10 and the center of the aperture stop 20 is calculated. Based on the above, the position of the exit end 10b of the light guide 10 or the σ stop 12 is adjusted.
[0070]
According to the telecentricity adjustment method of the FIA microscope according to the first embodiment, based on the exit end image and aperture stop image of the ride guide imaged by the CCD arranged to perform the telecentricity adjustment. The telecentricity adjustment is performed by adjusting the position of the light guide exit end or the position of the σ stop forming the secondary light source. That is, before the FIA microscope is mounted on the exposure apparatus, the telecentricity adjustment of the FIA microscope can be performed by a simple method using an inexpensive tool mirror, tool lens, and CCD for performing the telecentricity adjustment. it can. Therefore, the cost for adjusting the telecentricity of the FIA microscope can be reduced, and the telecentricity adjustment of the FIA microscope can be performed easily and with high accuracy.
[0071]
In the telecentricity adjustment method of the observation image device according to the first embodiment, the direction of the light toward the CCD 34 is changed by disposing the tool mirror 30 below the first objective lens 22. The tool lens 32 and the CCD 34 may be arranged on the straight line of the optical axis of the FIA microscope without arranging the tool mirror 30.
[0072]
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a flowchart showing a telecentricity adjustment method of an FIA microscope which is an image observation apparatus according to the second embodiment. The configuration of the FIA microscope according to the second embodiment is the same as that of the FIA microscope according to the first embodiment. In the description of the FIA microscope according to the second embodiment, the same configuration as that of the FIA microscope according to the first embodiment is the same as that used in the description of the first embodiment. The description will be made using the same reference numerals.
[0073]
First, as shown in FIG. 5, in the optical path between the first objective lens 22 and the CCD 28 (this embodiment) so that the imaging surface of the CCD 28 provided in the FIA microscope and the aperture stop 20 are conjugate. , A tool lens (tool optical system) 40 is disposed in the optical path between the reflecting mirror 26 and the CCD 28 (step S20). Next, the imaging surface of the CCD 28 is positioned at the focal position of the tool lens 40 arranged in step S20 (step S21). That is, the position of the tool lens 40 is moved and adjusted in the optical axis direction so that the imaging surface of the CCD 28 is positioned at the focal position of the tool lens 40. Next, the reflecting plate 42 is disposed at the focal position of the first objective lens 22 (step S22).
[0074]
Next, similarly to step S11 of FIG. 1 according to the first embodiment, a sigma stop having a sigma value of 1 or more is prepared, and the sigma value provided in the FIA microscope is 0.7 to 0.9. It replaces with the σ aperture (step S23). Next, similarly to step S12 according to the first embodiment, an aperture stop image (image aperture stop image) and a ride guide exit end (σ stop) image (on the imaging surface (predetermined surface) of the CCD 28 ( The position of the exit end 10b of the light guide 10 is moved and adjusted along the optical axis direction so that the image of the secondary light source is formed (formed) (step S24). In the adjustment in step S24, the aperture stop 20 may be moved in the optical axis direction instead of moving the exit end 10b of the light guide 10 in the optical axis direction.
[0075]
Next, the light is emitted from the exit end 10 b of the light guide 10, reflected by the reflecting plate 42 through the condenser lens 16, the aperture stop 20, and the first objective lens 22, and the first objective lens 22, the aperture stop 20, and the half mirror 18. The exit end image of the light guide is formed on the imaging surface of the CCD 28 based on the light that has passed through the second objective lens 24 and the reflecting mirror 26 and passed through the tool lens 40 and reached the imaging surface of the CCD 28 (step). S25). Further, the light guide 10 is emitted from the exit end 10b, is reflected by the reflector 42 through the condenser lens 16, the aperture stop 20, and the first objective lens 22, and the first objective lens 22, the aperture stop 20, the half mirror 18, An aperture stop image is formed on the imaging surface of the CCD 28 based on the light passing through the tool lens 40 and reaching the imaging surface of the CCD 28 through the second objective lens 24 and the reflecting mirror 26 (step S26).
[0076]
Next, both the exit end image of the ride guide formed in step S25 and the aperture stop image formed in step S26 are imaged by the CCD 28 (step S27). Next, based on the exit end image and aperture stop image of the light guide imaged in step S27, the position of the exit end 10b or the σ stop 12 of the light guide 10 is adjusted so that the FIA microscope becomes telecentric (step S27). S28). That is, the position of the exit end 10b of the light guide 10 or the σ stop 12 is adjusted so that the aperture stop image and the exit end image of the light guide are concentric. Here, when the aperture stop 20 is fixed and the position of the aperture stop 20 is decentered with respect to the optical axis of the FIA microscope, the aperture stop image and the exit end image of the light guide are concentric. Even when the aperture stop is adjusted, the telecentricity adjustment is not performed accurately because the aperture stop 20 is eccentric. Therefore, an amount obtained by subtracting the amount of deviation between the optical axis of the FIA microscope and the center of the aperture stop 20 from the amount of deviation between the center of the exit end 10b of the light guide 10 and the center of the aperture stop 20 is calculated. Based on the above, the position of the exit end 10b of the light guide 10 or the σ stop 12 is adjusted.
[0077]
According to the telecentricity adjustment method of the FIA microscope according to the second embodiment, the tool lens is disposed in the optical path between the second objective lens and the CCD, and the image is taken by the CCD of the FIA microscope. Telecentricity adjustment is performed based on the exit end image and aperture stop image of the light guide. That is, before the FIA microscope is mounted on the exposure apparatus, telecentricity adjustment can be performed by a simple method using an inexpensive tool lens and a CCD provided in the FIA microscope. Therefore, the cost for adjusting the telecentricity of the FIA microscope can be reduced, and the telecentricity adjustment of the FIA microscope can be performed easily and with high accuracy.
[0078]
In the telecentricity adjustment method of the FIA microscope according to the above-described embodiment, a diffusion plate or the like is inserted between the light guide exit end and the aperture stop in order to set the σ value of the σ stop to 1 or more. May be. In this case, after arranging the tool for adjusting the telecentricity of the FIA microscope (step S10 in FIG. 2 in the first embodiment and step S20 in FIG. 4 in the second embodiment). A diffusion plate is inserted between the exit end 10 b of the light guide 10 and the aperture stop 20. The diffuser plate or the like is preferably inserted in the vicinity of the field stop 14 disposed at the rear focal position of the condenser lens 16. Further, since the divergence degree of the diffusion plate is determined so that the exit end image of the light guide can be discriminated on the imaging surfaces of the CCDs 28 and 34, the exit end image of the light guide and the aperture stop image can be observed simultaneously. It becomes possible.
[0079]
Further, in the telecentricity adjustment method of the FIA microscope according to the above-described embodiment, the aperture stop 20 is disposed between the half mirror 18 and the first objective lens 22, but the first objective lens 22 and the CCD 28 are arranged. May be arranged at any position between.
[0080]
Further, in the telecentricity adjustment method for the FIA microscope according to the above-described embodiment, the center of the imaging surface of the CCDs 28 and 34 and the optical axis of the FIA microscope are matched in advance, and the aperture stop 20 with reference to the CCDs 28 and 34. The telecentricity of the FIA microscope may be adjusted by adjusting the position of the exit end 10b of the light guide 10.
[0081]
Further, when the aperture stop 20 is disposed so as to be orthogonal to the optical axis of the FIA microscope, first, in step 22 of the telecentricity adjustment method (FIG. 4) of the FIA microscope according to the second embodiment. The center shift of the aperture stop 20 can be detected based on the aperture stop image observed by the CCD 28.
[0082]
Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a flowchart showing a focus position measuring method of the FIA microscope according to the third embodiment. The configuration of the FIA microscope according to the third embodiment is the same as that of the FIA microscope according to the first embodiment. In the description of the FIA microscope according to the third embodiment, the same configuration as that of the FIA microscope according to the first embodiment is used in the description of the first embodiment. The description will be made using the same reference numerals.
[0083]
First, the σ stop (illumination σ stop) 12 provided in the FIA microscope shown in FIG. 7 is replaced with a σ stop having a σ value of 0.35 (step S30). Next, the exit end 10b (secondary light source) of the light guide 10 is decentered with respect to the optical axis of the FIA microscope so that the numerical aperture is 0.1 and the illumination light eccentricity is 50 mrad (step S31). Instead of decentering the exit end 10b of the light guide 10, the σ stop replaced in step S30 may be decentered. Further, in the eccentric direction of the illumination light, the influence of bending of the illumination light by the half mirror 18 disposed between the exit end 10b of the light guide 10 and a linear pattern described later is also taken into consideration.
[0084]
FIG. 8 is a diagram illustrating the arrangement of the light guide exit end image 50 and the aperture stop image 52 on the pupil when the exit end 10b of the light guide 10 is decentered in step S31. The arrangement of the exit end image 50 and the aperture stop image 52 of the light guide on the pupil shown in FIG. 8 is the same as the tool mirror 30 and the tool lens used in the telecentricity adjustment method (FIG. 1) according to the first embodiment. 32 and can be confirmed directly by the CCD 34.
[0085]
Next, an indicator 48 having a 20 μm line width Cr blanked line pattern as shown in FIG. 9 is prepared. A position (the substrate stage of the exposure apparatus) that becomes the focal position of the FIA microscope when the FIA microscope is incorporated in the exposure apparatus so that the linear pattern extends in a direction perpendicular to the eccentric direction of the exit end 10b of the light guide 10 The index 48 is arranged at or near the substrate surface position held by (step S32). That is, it is arranged on the surface where the object to be observed by the FIA microscope is arranged or in the vicinity of the surface. The index 48 may be positioned and arranged on a plane conjugate with or near a position where an object to be observed by the FIA microscope is arranged.
[0086]
Next, the aerial image intensity distribution is measured when the linear pattern index 48 is irradiated with illumination light having a wavelength of 500 to 700 nm, and a differential value thereof is calculated (step S33). A thick solid line L1 in FIG. 10 is an aerial image intensity distribution, and a thin solid line L2 in FIG. 10 is a graph showing a differential value thereof. The differential peak value on the left side of the graph is the pattern edge A, the differential value is a, the differential peak value on the right side is the pattern edge B, and the differential value is b, and T = (a + b) / (ab) is defined.
[0087]
Next, whether or not the FIA microscope is in an ideal imaging state, that is, whether or not spherical aberration and coma remain in the FIA microscope is based on a graph in which T values are plotted against defocus amounts. (Step S34). FIG. 11 is a graph showing the T value with respect to the defocus amount when it is determined that spherical aberration and coma do not remain in the FIA microscope. If it is determined that the spherical aberration and the coma aberration do not remain in the FIA microscope based on the graph in which the T value is plotted against the defocus amount, the non-target property of the aerial image intensity distribution measured in step S33 is considered. Based on this, the best focus position of the FIA microscope is measured (step S37). That is, the position when T = 0 (a = −b) shown in the graph of FIG. 11 is the best focus position.
[0088]
On the other hand, the T value with respect to the defocus amount when it is determined that spherical aberration remains in the FIA microscope is shown in the solid line graph of FIG. If spherical aberration remains in the FIA microscope, the position of the exit end 10b of the light guide 10 is decentered to a position symmetrical to the optical axis of the FIA microscope with respect to the eccentric position of the exit end 10b of the light guide 10 in step S31. (Step S35), the aerial image intensity distribution is measured (step S36). The T value with respect to the defocus amount in step S36 is shown in the broken line graph of FIG. When spherical aberration remains, T = 0 does not become the focal position, but the best focus position is a position where the contrast of the illumination light peaks as shown in the graph of FIG. That is, it coincides with the position where the solid line and the broken line in FIG. Therefore, the best focus position of the FIA microscope when the spherical aberration remains is the position where the T value before rotating the illumination light eccentricity 180 degrees and the T value after rotating the illumination light eccentricity 180 degrees intersect ( Step S37).
[0089]
Further, the T value with respect to the defocus amount when it is determined that the coma aberration remains in the FIA microscope is shown in the solid line graph of FIG. When coma aberration remains in the FIA microscope, it is decentered to a position symmetrical to the optical axis of the FIA microscope with respect to the eccentric position of the exit end 10b of the light guide 10 in step S31 (step S35), and the aerial image intensity distribution. Is measured (step S36). The T value with respect to the defocus amount in step S36 is shown in the broken line graph of FIG. When coma remains, T = 0 does not become the focal position, but the best focus position coincides with the position where the solid line and the broken line intersect. Therefore, the best focus position of the FIA microscope when the coma aberration remains is the position where the T value before rotating the illumination light eccentricity 180 degrees and the T value after rotating the illumination light eccentricity 180 degrees intersect, It becomes the focal position (step S37).
[0090]
According to the focus position measuring method of the FIA microscope according to the third embodiment, a linear pattern is used, the aerial image intensity distribution of the linear pattern is measured, and the asymmetry of the measured aerial image intensity distribution is reduced. Based on this, the focus position of the FIA microscope is measured. That is, the focus position can be measured by a simple method before the FIA microscope is mounted on the exposure apparatus. Therefore, the time and cost for measuring the focus position of the FIA microscope can be reduced, and the focus position measurement of the FIA microscope can be performed easily and with high accuracy.
[0091]
In the focus position measuring method of the FIA microscope according to the third embodiment, the T value changes substantially linearly with respect to the optical axis direction within the depth of focus. Therefore, the inclination of the T value can be calculated in advance by calculation or the like, and the position in the optical axis direction can be calculated from the T value. Further, the coma aberration amount can also be obtained based on the value when the T values intersect, that is, the T value at the best focus position.
[0092]
Further, by using the FIA microscope focus position measurement method according to the third embodiment, the focus position of the AIS that is the image observation apparatus can be measured. That is, an independent illumination system configured to decenter the illumination light is prepared, and the illumination system is decentered with respect to the optical axis of the AIS. Next, an index 48 having a 20 μm line width Cr-extracted linear pattern as shown in FIG. 9 is arranged at an AIS index position so as to extend in a direction perpendicular to the eccentric direction. Next, an aerial image intensity distribution when the illumination light is irradiated onto the index 48 is measured, and a differential value thereof is calculated. Next, as in the third embodiment, the AIS best focus position is measured based on the calculated asymmetry of the aerial image intensity distribution. According to this AIS focus position measurement method, the AIS index position with respect to the AIS can be measured with high accuracy before the AIS is mounted on the exposure apparatus.
[0093]
Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 15 is a flowchart showing a focus position measuring method of the FIA microscope according to the fourth embodiment. The configuration of the FIA microscope according to the fourth embodiment is the same as that of the FIA microscope according to the first embodiment. In the description of the FIA microscope according to the fourth embodiment, the same configuration as that of the FIA microscope according to the first embodiment is used in the description of the first embodiment. The description will be made using the same reference numerals.
[0094]
First, the σ stop 12 provided in the FIA microscope shown in FIG. 7 is replaced with a σ stop having a σ value of 0.35 (step S40). Next, the exit end 10b (secondary light source) of the light guide 10 is decentered with respect to the optical axis of the FIA microscope so that the numerical aperture is 0.1 and the illumination light eccentricity is 50 mrad (step S41). Instead of decentering the exit end 10b of the light guide 10, the σ stop replaced in step S40 may be decentered. FIG. 8 is a diagram showing the arrangement of the light guide exit end image 50 and the aperture stop image 52 on the pupil when the exit end 10b of the light guide 10 is decentered in step S41.
[0095]
Next, at the position that becomes the focal position of the FIA microscope (the position of the substrate surface held on the substrate stage of the exposure apparatus when incorporated in the exposure apparatus) or in the vicinity thereof, the Cr removal with a 20 μm line width as shown in FIG. The indicator 48 having a linear pattern is arranged so that the linear pattern extends in a direction perpendicular to the eccentric direction (step S42). That is, it is arranged on the surface where the object to be observed by the FIA microscope is arranged or in the vicinity of the surface. The index 48 may be positioned and arranged on a plane conjugate with or near a position where an object to be observed by the FIA microscope is arranged.
[0096]
Next, illumination light is irradiated and the linear pattern position of the index 48 is measured (step S43). Next, the position of the exit end 10b of the light guide 10 is decentered to a position symmetric with respect to the position decentered in step S41 and the optical axis (step S44). Next, illumination light is irradiated and the linear pattern position of the index 48 is measured (step S45). FIG. 16 is a diagram illustrating the arrangement of the light guide exit end image 62 and the aperture stop image 64 on the pupil when the illumination light is decentered in step S44 to a position perpendicular to the position of step S41 and the optical axis. .
[0097]
Next, the best focus position of the FIA microscope is measured (step S46). That is, at the best focus position of the FIA microscope, the linear pattern position of the index 48 does not change even if the eccentric amount of the illumination light is changed. Therefore, when the position of the linear pattern measured in step S43 coincides with the position of the linear pattern measured in step S45, the measured position becomes the best focus position of the FIA microscope. On the other hand, if the position of the linear pattern measured in step S43 and the position of the linear pattern measured in step S45 do not match, the measured position is not the best focus position of the FIA microscope and needs to be adjusted. .
[0098]
According to the focus position measurement method of the FIA microscope according to the fourth embodiment, a linear pattern is used, the image position of the linear pattern is measured, and based on the measured image position of the linear pattern, Measure the focus position of the FIA microscope. That is, the focus position can be measured by a simple method before the FIA microscope is mounted on the exposure apparatus. Therefore, the time and cost for performing the focus position measurement of the FIA microscope can be reduced, and the focus position measurement of the FIA microscope can be performed easily and with high accuracy.
[0099]
In the focus position measurement method of the FIA microscope according to the third and fourth embodiments, focus position measurement is performed using a linear pattern (bright / dark pattern) extending perpendicular to the eccentric direction. The focus position of the FIA microscope may be measured using the phase pattern. That is, the phase pattern is arranged in step S32 in the third embodiment and in step S42 in the fourth embodiment so that the pattern extends in a direction perpendicular to the eccentric direction. Then, the light intensity distribution of the phase pattern is measured, and the focus position of the FIA microscope is measured based on the asymmetry of the light intensity of the phase pattern. Note that details of the phase pattern are disclosed in JP-A-2000-77295.
[0100]
Further, the focus position may be measured by combining the focus position measurement methods of the FIA microscopes according to the third and fourth embodiments. That is, the focus position of the FIA microscope may be measured based on the asymmetry of the aerial image intensity distribution of the line pattern and the position measurement of the line pattern. In this case, the focus position of the FIA microscope can be measured with higher accuracy.
[0101]
Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 17 is a view showing the arrangement of the projection exposure apparatus according to the fifth embodiment.
[0102]
As shown in FIG. 17, the light beam emitted from the light source 72 composed of a high-pressure mercury lamp arranged at the first focal position of the elliptical mirror 70 is reflected by the elliptical mirror 70 and the dichroic mirror 74, and is reflected by the mirror of the elliptical mirror 70. The light is condensed at the second focal position of the elliptical mirror 70. The light beam condensed at the second focal position of the elliptical mirror 70 passes through the relay lens 76 and enters the fly-eye lens 78 that is an optical integrator element. The fly-eye lens 78 is configured by arranging a large number of lens elements vertically and horizontally and densely so that the optical axes of the large number of lens elements having positive refractive power are parallel to the optical axis of the illumination optical system. ing. Therefore, the light beam incident on the fly-eye lens 78 is divided into wavefronts by a large number of lens elements, and one light source image is formed on the rear focal plane of each lens element constituting the fly-eye lens 78. That is, on the rear focal plane of the fly-eye lens 78, a substantial surface light source consisting of a large number of light source images, that is, a secondary light source is formed.
[0103]
The light beam from the secondary light source formed on the rear focal plane of the fly-eye lens 78 passes through the σ stop 80, the condenser lens 82, and the collimating lens 84, and is reflected by the reflecting mirror 86. The light beam reflected by the reflecting mirror 86 illuminates the mask M almost uniformly by the condenser lens 88. The light flux from the mask M enters the projection optical system PL, and the pattern image of the mask M is projected and exposed on a plate (photosensitive substrate) P.
[0104]
In the projection exposure apparatus according to the fifth embodiment, a mask stage (first surface, not shown) on which a mask M is placed and a plate stage on which a plate P is placed (in order to perform optimum exposure) Image observation devices 90, 92, and 94 are provided for aligning (aligning) the second surface (not shown). Since the FIA microscopes according to the first to fourth embodiments are used for the image observation apparatuses 90 and 92, detailed description of the configuration is omitted. Further, the FIA microscopes 90 and 92 are telecentricity adjusted by at least one of the telecentricity adjustment methods of the FIA microscopes according to the first and second embodiments. The FIA microscopes 90 and 92 measure the focus position by at least one of the focus position measurements of the FIA microscopes according to the third and fourth embodiments.
[0105]
The image observation apparatus 94 uses an AIS provided with a relay lens 98 in which the CCD 100 is embedded in the substrate stage and the surface position of the plate P is enlarged and projected onto the imaging surface of the CCD 100. The AIS 94 includes an index 96 at or near the substrate stage surface position.
[0106]
FIG. 18 is a flowchart for explaining a focus position measuring method of the projection optical system PL of the projection exposure apparatus according to the fifth embodiment.
[0107]
First, the σ stop (illumination σ stop) 80 in the illumination optical system of the exposure apparatus shown in FIG. 17 is replaced with a σ stop having a σ value of 0.35 (step S50). Next, the σ stop is decentered with respect to the optical axis of the projection optical system PL so that the numerical aperture is 0.1 and the illumination light eccentricity is 50 mrad (step S51). That is, the secondary light source formed on the rear focal plane of the fly-eye lens 78 is decentered with respect to the optical axis of the projection optical system PL. Note that a σ stop having a shape as shown in FIG. 19 may be created, and may be decentered by shading one side by a shutter or the like.
[0108]
Next, the mask M is irradiated with light from the secondary light source through the σ stop decentered in step S51 (step S52). Next, an indicator 48 having a 20 μm line width Cr blanked line pattern as shown in FIG. 9 is prepared. An index 48 is arranged on the mask stage of the exposure apparatus or in the vicinity thereof so that the linear pattern extends in a direction perpendicular to the eccentric direction (step S53). The index 48 may be positioned and arranged on a plane conjugate with the mask stage or in the vicinity thereof.
[0109]
Next, the spatial image intensity distribution of the linear pattern when the illumination light with a wavelength of 500 to 700 nm is irradiated onto the index 48 is measured by the CCD embedded in the substrate stage, and the differential of the measured aerial image intensity distribution. A value is calculated (step S54). The T value is defined by the same method as the focus position measuring method of the FIA microscope according to the third embodiment.
[0110]
When spherical aberration remains in the projection optical system PL (step S55), the projection optical system starts from the position of the σ stop decentered in step S51, as in the focus position measurement method of the FIA microscope according to the third embodiment. The σ stop is decentered at a position symmetrical to the PL optical axis (step S56), and the aerial image intensity distribution is measured (step S57). When the projection optical system PL has spherical aberration, T = 0 is not obtained at the focal position, but the best focus position is a position where the contrast of the illumination light reaches a peak. Therefore, the best focus position of the projection optical system PL when there is spherical aberration is a position where the T value before rotating the illumination light eccentricity 180 degrees and the T value after rotating the illumination light eccentricity 180 degrees intersect. (Step S58).
[0111]
If coma remains in the projection optical system PL (step S55), the projection is performed from the position of the σ stop decentered in step S51, as in the focus position measuring method of the FIA microscope according to the third embodiment. The σ stop is decentered at a position symmetrical to the optical axis of the optical system PL (step S56), and the aerial image intensity distribution is measured (step S57). When the projection optical system PL has coma aberration, T = 0 does not become the focal position, but the best focus position is obtained by rotating the illumination light eccentricity by 180 degrees and the T value before rotating the illumination light eccentricity by 180 degrees. It becomes the position where the T value later intersects, that is, the focal position (step S58).
[0112]
On the other hand, when spherical aberration and coma do not remain in the projection optical system PL (step S55), the best focus position of the projection optical system PL is determined based on the asymmetry of the aerial image intensity distribution measured in step S54. measure. That is, the position when T = 0 is the best focus position (step S58).
[0113]
In step S54, the aerial image intensity distribution of the linear pattern of the index 48 is measured, and at the same time, the focus position measurement similar to that in steps S54 to S58 is performed on the aerial image intensity distribution of the index provided in the AIS. As a result, the shift amount of the focus position of the index with respect to the AIS can be measured. By measuring the deviation amount of the focus position of the index with respect to the AIS, the value obtained by subtracting the deviation amount from the focus position measured in step S58 becomes the best focus position of the projection optical system PL, and a more accurate best focus position is measured. can do.
[0114]
According to the focus position measurement method for a projection optical system according to the fifth embodiment, a linear pattern is used, the aerial image intensity distribution of the linear pattern is measured, and the measured asymmetric image intensity distribution is asymmetry. Based on the above, the focus position of the projection optical system is measured. Therefore, it is possible to reduce time and cost for measuring the focus position of the projection optical system, and it is possible to easily and accurately measure the focus position of the projection optical system.
[0115]
In the focus position measuring method of the projection optical system according to the fifth embodiment, FIA microscope marks created with a plurality of types of phase patterns are placed outside the AIS field of view on the AIS index. By performing the same measurement as the focus position measurement method of the projection optical system according to the embodiment, it may be used to adjust the focus position of the FIA microscope mounted on the exposure apparatus. For example, a pattern is formed by etching a glass to provide a step, and the step is an integral multiple of λ / 2 and an odd multiple of λ / 4 with respect to the center wavelength of the FIA microscope illumination wavelength region, so that the contrast is A pattern provided with a plurality of step patterns such as a high pattern and a low pattern is placed outside the AIS visual field on the AIS index. Next, the σ stop having a σ value of 0.35 is decentered with respect to the optical axis of the projection optical system PL, and the light intensity distribution of the step pattern when the index is irradiated is measured. Based on the asymmetry of the measured light intensity distribution, the focus position of the FIA microscope is measured. The adjustment pattern plate of the FIA microscope may be prepared separately from the AIS index.
[0116]
Next, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 20 is a flowchart showing a focus position measuring method of the projection optical system according to the sixth embodiment. The configuration of the exposure apparatus according to the sixth embodiment is the same as that of the exposure apparatus according to the fifth embodiment. In the description of the exposure apparatus according to the sixth embodiment, the same reference numerals as those used in the description of the fifth embodiment are used for the configuration of the exposure apparatus according to the fifth embodiment. Give an explanation.
[0117]
First, the σ stop 80 provided in the exposure apparatus shown in FIG. 17 is replaced with a σ stop having a σ value of 0.35 (step S60). Next, the σ stop is decentered with respect to the optical axis of the projection optical system PL so that the numerical aperture is 0.1 and the illumination light eccentricity is 50 mrad (step S61). That is, the secondary light source formed on the rear focal plane of the fly-eye lens 78 is decentered with respect to the optical axis of the projection optical system PL. Note that a σ stop having a shape as shown in FIG. 19 may be created, and may be decentered by shading one side by a shutter or the like.
[0118]
Next, the mask M is irradiated with light from the secondary light source through the σ stop decentered in step S61 (step S62). Next, an indicator 48 having a 20 μm line width Cr blanked line pattern as shown in FIG. 9 is prepared. An index 48 is arranged on the mask stage of the exposure apparatus or in the vicinity thereof so that the linear pattern extends in a direction perpendicular to the eccentric direction (step S63). The index 48 may be positioned and arranged on a plane conjugate with the mask stage or in the vicinity thereof.
[0119]
Next, the linear pattern position of the index 48 is measured by the CCD 100 of the AIS94 (step S64). Next, the σ stop is decentered to a position symmetrical to the position of step S61 and the optical axis (step S65), and the linear pattern position of the index 48 is measured by the CCD 100 of the AIS94 (step S66).
[0120]
Next, the best focus position of the projection optical system PL is measured (step S67). That is, at the best focus position of the projection optical system PL, the linear pattern position of the index 48 does not change even if the illumination light eccentricity is changed. Therefore, when the position of the linear pattern measured in step S64 matches the position of the linear pattern measured in step S66, the measured position becomes the best focus position of the projection optical system PL. On the other hand, if the position of the linear pattern measured in step S64 and the position of the linear pattern measured in step S66 do not match, the measured position is not the best focus position of the projection optical system PL and needs to be adjusted. There is.
[0121]
According to the focus position measuring method of the FIA microscope according to the sixth embodiment, a linear pattern is used, the image position of the linear pattern is measured, and based on the measured image position of the linear pattern, Measure the focus position of the projection optical system. Therefore, it is possible to reduce time and cost for measuring the focus position of the projection optical system, and it is possible to easily and accurately measure the focus position of the projection optical system.
[0122]
Further, the focus position may be measured by combining the focus position measurement methods of the projection optical system according to the fifth and sixth embodiments. In other words, the focus position of the projection optical system may be measured based on the asymmetry of the aerial image intensity distribution of the linear pattern and the position measurement of the linear pattern. In this case, since the measurement is performed by combining the focus position measurement methods of the projection optical system, the focus position of the projection optical system can be measured with higher accuracy.
[0123]
Next, a seventh embodiment of the present invention will be described with reference to the drawings. FIG. 21 is a flowchart showing a defocus amount measuring method of the FIA microscope according to the seventh embodiment. The configuration of the exposure apparatus according to the seventh embodiment is the same as that of the exposure apparatus according to the fifth embodiment. In the description of the exposure apparatus according to the seventh embodiment, the same configuration as that of the exposure apparatus according to the fifth embodiment is the same as that used in the description of the fifth embodiment. Explanation will be made using reference numerals.
[0124]
The configuration of the FIA microscopes 90 and 92 mounted on the exposure apparatus according to the seventh embodiment is the same as that of the FIA microscope according to the first embodiment. In the description of the FIA microscope according to the seventh embodiment, the same reference numerals as those used in the first embodiment are assigned to the same configurations as those of the FIA microscope according to the first embodiment. A description will be given.
[0125]
First, an index 48 having a 20 μm line width Cr-extracted linear pattern as shown in FIG. 9 is placed perpendicular to the eccentric direction at the position of the field stop 14 of the FIA microscope shown in FIG. 22 or in the vicinity thereof. It arrange | positions so that it may extend in a direction (step S70). Next, the reflecting object 60 is placed on the substrate stage (step S71).
[0126]
Next, the σ stop 12 provided in the FIA microscopes 90 and 92 is replaced with a σ stop having a σ value of 0.35, so that the numerical aperture is 0.1 and the illumination light eccentricity is 50 mrad. Is decentered with respect to the optical axis of the FIA microscope (step S72). Instead of decentering the exit end 10b of the light guide 10, the replaced σ stop may be decentered.
[0127]
Next, illumination light is irradiated, and the linear pattern position of the index 48 is measured by the CCD 28 provided in the FIA microscopes 90 and 92 in the same manner as the focus position measuring method of the FIA microscope according to the fourth embodiment. (Step S73). Next, the exit end 10b of the light guide 10 is decentered to a position symmetrical with respect to the position of step S71 and the optical axis (step S74). Next, illumination light is irradiated, and the linear pattern position of the index 48 is measured by the CCD 28 provided in the FIA microscopes 90 and 92 (step S75), and the focus position measurement of the FIA microscope according to the fourth embodiment is performed. Similar to the method, the defocus amounts of the FIA microscopes 90 and 92 are measured (step S76). In this case, since the index pattern reflected by the substrate stage is used for defocus amount measurement, half of the measured value is the defocus amount of the FIA microscopes 90 and 92.
[0128]
According to the defocus amount measuring method of the FIA microscope according to the seventh embodiment, the defocus amount can be measured by a simple method with the FIA microscope mounted on the exposure apparatus. By subtracting the measured defocus amount from the position of the measured mask or photosensitive substrate, the position of the mask or photosensitive substrate can be accurately measured. Therefore, since the mask and the photosensitive substrate are aligned based on the position of the mask and the photosensitive substrate accurately measured by the FIA microscope, a fine exposure pattern can be satisfactorily exposed.
[0129]
In the defocus amount measuring method of the FIA microscope according to the seventh embodiment, the defocus amount is measured based on the position measurement value of the index pattern. However, the asymmetry of the aerial image intensity distribution of the index pattern The defocus amount may be measured by performing measurement similar to the focus position measurement method according to the third embodiment.
[0130]
In the FIA microscope defocus amount measuring method according to the seventh embodiment, the position of the index pattern is measured by the CCD 34 provided in the FIA microscopes 90 and 92. The position of the index pattern may be measured by the AIS94 CCD 100 provided in the exposure apparatus. In this case, it is not necessary to place the reflecting object 60 on the substrate stage, and the measurement value measured by measuring the position of the index pattern becomes the defocus amount of the FIAs 90 and 92.
[0131]
Further, an illumination system for illuminating the index pattern may be provided separately from the illumination light of the FIA microscopes 90 and 92 and used as alignment focus position measurement during normal alignment measurement on the exposure apparatus.
[0132]
The exposure apparatus according to the eighth embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 23 is a perspective view showing an overall schematic configuration of an exposure apparatus according to the eighth embodiment. In the eighth embodiment, a mask (first substrate) M2 and a plate (second substrate) P2 as a substrate are provided for a projection optical system PL20 including a plurality of catadioptric projection optical units PL1 to PL5. A step-and-scan type exposure apparatus that transfers an image of a pattern DP (see FIG. 24) of the liquid crystal display element formed on the mask M2 onto the plate P2 as a substrate while moving the film relatively will be described as an example. To do.
[0133]
In the following description, the XYZ rectangular coordinate system shown in each drawing is set, and the positional relationship of each member will be described with reference to this XYZ rectangular coordinate system. The XYZ orthogonal coordinate system is set so that the X axis and the Y axis are parallel to the plate P2, and the Z axis is set to a direction orthogonal to the plate P2. In the XYZ coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z-axis is set vertically upward. In the present embodiment, the direction (scanning direction) in which the mask M2 and the plate P2 are moved is set to the X-axis direction.
[0134]
The exposure apparatus of the eighth embodiment uniformly illuminates a mask M2 supported in parallel with the XY plane via a mask holder (not shown) on a mask stage (first stage) MS (see FIG. 24). The illumination optical system IL is provided. 24 is a side view of the illumination optical system IL, and the same members as those shown in FIG. 23 are denoted by the same reference numerals. Referring to FIGS. 23 and 24, the illumination optical system IL includes a light source 101 made of, for example, a mercury lamp or an ultrahigh pressure mercury lamp. Since the light source 101 is disposed at the first focal position of the elliptical mirror 102, the illumination light beam emitted from the light source 101 forms a light source image at the second focal position of the elliptical mirror 2 via the dichroic mirror 103.
[0135]
In the present embodiment, the light emitted from the light source 101 is reflected by the reflective film formed on the inner surface of the elliptical mirror 102 and the dichroic mirror 103, whereby the g-line (436 nm) light and the h-line (405 nm) are reflected. ) And i-line (365 nm) light including a light having a wavelength range of 300 nm or more is formed at the second focal position of the elliptical mirror 102. That is, components that are unnecessary for exposure outside the wavelength region including g-line, h-line, and i-line are removed when reflected by the elliptical mirror 102 and the dichroic mirror 103.
[0136]
A shutter 104 is disposed at the second focal position of the elliptical mirror 102. The shutter 104 includes an opening plate 104a (see FIG. 24) disposed obliquely with respect to the optical axis AX1, and a shielding plate 104b (see FIG. 24) that shields or opens the opening formed in the opening plate 104a. . The shutter 104 is disposed at the second focal position of the elliptical mirror 102 because the illumination light beam emitted from the light source 101 is focused, so that the opening formed in the aperture plate 104a is shielded with a small amount of movement of the shield plate 104b. This is because the amount of the illumination light beam passing through the aperture can be changed abruptly to obtain a pulsed illumination light beam.
[0137]
The divergent light beam from the light source image formed at the second focal position of the elliptical mirror 102 is converted into a substantially parallel light beam by the collimator lens 105 and enters the wavelength selection filter 106. The wavelength selection filter 106 transmits only a light beam in a wavelength region including g-line, h-line, and i-line. The light that has passed through the wavelength selection filter 106 forms an image again via the relay lens 108. An incident end 109a of the light guide 109 is disposed in the vicinity of the imaging position. The light guide 109 is, for example, a random light guide fiber configured by randomly bundling a large number of fiber strands, and has the same number of incident ends 109a as the number of light sources 101 (one in FIG. 23), and a projection optical system. The same number of exit ends as the number of projection optical units (partial projection optical systems) constituting the PL (five in FIG. 23), that is, the exit end 109b and the other four exit ends (in FIG. 24, only the exit end 109b is shown). ). Thus, the light incident on the incident end 109a of the light guide 109 propagates through the inside thereof, and then is divided and emitted from the emission end 109b and the other four emission ends. When the amount of light is insufficient with only one light source 101, a plurality of light sources are provided, and each light source has a plurality of incident ends provided. It is preferable to provide a light guide that divides into the same amount of light and emits from each exit end.
[0138]
As shown in FIG. 24, at the incident end 109a of the light guide 109, a blade 110 configured to be able to continuously change the position is disposed. This blade 110 continuously changes the intensity of light emitted from the exit end 109b of the light guide 109 and each of the other four exit ends by shielding a part of the entrance end 109a of the light guide 109. belongs to. Control of the light shielding amount with respect to the incident end 109 a of the light guide 109 of the blade 110 is performed by the main control system 120 in FIG. 24 controlling the driving device 119.
[0139]
Between the exit end 109b of the light guide 109 and the mask M2, a collimating lens 111b, a fly-eye integrator 112b, an aperture stop 113b (not shown in FIG. 23), a beam splitter 114b (not shown in FIG. 23), and a condenser The lens system 115b is arranged in order. Similarly, between the other four exit ends of the light guide 109 and the mask M2, a collimating lens, a fly-eye integrator, an aperture stop, a beam splitter, and a condenser lens system are arranged in that order. .
[0140]
Here, for simplification of description, the configuration of the optical member provided between each exit end of the light guide 109 and the mask M2 is provided between the exit end 109b of the light guide 109 and the mask M2. The collimating lens 111b, the fly-eye integrator 112b, the aperture stop 113b, the beam splitter 114b, and the condenser lens system 115b will be representatively described.
[0141]
The divergent light beam emitted from the exit end 109b of the light guide 109 is converted into a substantially parallel light beam by the collimator lens 111b and then enters the fly-eye integrator 112b. The fly-eye integrator 112b is configured by arranging a large number of positive lens elements vertically and horizontally and densely so that the central axis thereof extends along the optical axis AX2. Therefore, the light beam incident on the fly-eye integrator 112b is divided into wavefronts by a large number of lens elements, and a secondary light source composed of the same number of light source images as the number of lens elements is formed on the rear focal plane (that is, in the vicinity of the exit surface). Form. That is, a substantial surface light source is formed on the rear focal plane of the fly-eye integrator 112b.
[0142]
Light beams from a number of secondary light sources formed on the rear focal plane of the fly-eye integrator 112b are limited by an aperture stop 113b disposed near the rear focal plane of the fly-eye integrator 112b, The light enters the condenser lens system 115b via the splitter 114b. The aperture stop 113b is disposed at a position optically conjugate with the pupil plane of the corresponding projection optical unit PL1, and has a variable aperture for defining the range of the secondary light source that contributes to illumination. The aperture stop 113b changes the aperture diameter of the variable aperture portion to change the σ value for determining the illumination condition (the pupil plane relative to the aperture diameter of the pupil plane of each of the projection optical units PL1 to PL5 constituting the projection optical system PL20). The ratio of the aperture diameter of the secondary light source image above is set to a desired value.
[0143]
The light flux through the condenser lens system 115b illuminates the mask M2 on which the pattern DP is formed in weight. Similarly, the divergent light beams emitted from the other four light exit ends of the light guide 109 are respectively weighted through the mask M2 through the collimator lens, the fly-eye integrator, the aperture stop, the beam splitter, and the condenser lens in this order. Irradiate. That is, the illumination optical system IL illuminates a plurality of trapezoidal regions (illumination visual fields) arranged in the Y-axis direction (five in FIG. 23 in total) on the mask M2. The light source included in the illumination optical system IL may be an ultraviolet radiation type LED or LD.
[0144]
On the other hand, the light passing through the beam splitter 114b provided in the illumination optical system IL is received by an integrator sensor 117b including a photoelectric conversion element via a condenser lens 116b as shown in FIG. The photoelectric conversion signal of the integral overnight sensor 117b is supplied to the main control system 120 via a peak hold circuit and an A / D converter (not shown). A correlation coefficient between the output of the integrator sensor 117b and the energy (exposure amount) per unit area of the light irradiated on the surface of the plate P2 is obtained in advance and stored in the main control system 120.
[0145]
The main control system 120 is in synchronization with stage system operation information from a stage controller (not shown) that controls the plate stage (second stage) on which the plate P2 is placed and the mask stage MS on which the mask M2 is placed. Timing for controlling the opening / closing operation of the shutter 104, outputting a control signal to the driving device 119 in accordance with the photoelectric conversion signal output from the integrator sensor 117b, and irradiating the mask M2 with illumination light from the illumination optical system IL And control the intensity of the illumination light.
[0146]
The illumination optical system IL is configured so that its illumination optical characteristics (for example, telecentricity and illuminance unevenness) can be varied. For example, at least some of the plurality of lenses constituting the condenser lens system 115b are moved in the optical axis AX2 direction (Z direction), tilted with respect to the optical axis AX2 (θx, θy directions), and with respect to the optical axis AX2. Thus, the illuminance unevenness (isotropic component or tilt component with respect to the optical axis) can be adjusted by decentering (X and Y directions). Further, the illuminance unevenness (tilt component) can also be corrected by tilting the exit end 109b of the light guide 109 (in the θx and θy directions). Then, by moving the fly-eye integrator 112b in the optical axis AX2 direction (Z direction), the telecentricity magnification component (rotationally symmetric with respect to the optical axis) can be adjusted, and the fly-eye integrator 112b and The tilt component of telecentricity can be adjusted by moving the aperture stop 113b integrally or by moving the aperture stop 113b in the direction perpendicular to the optical axis (in the XY plane). In addition, for adjustment of illuminance unevenness, the opening width in the scanning direction is orthogonal to the scanning direction (non-scanning) in the vicinity of the mask surface (plate surface) or in the optical conjugate with the mask surface (plate surface) or in the vicinity thereof. It is also possible to correct by arranging a field stop that is different in (direction). For details of this correction method, refer to, for example, JP-A-7-142313. In such a correction method, a configuration may be provided in which a density distribution filter having a distribution in which the transmission characteristics can correct illuminance unevenness in the non-scanning direction is used instead of changing the width of the aperture of the field stop.
[0147]
The light from each illumination area on the mask M2 is a projection optical system composed of a plurality of projection optical units PL1 to PL5 (a total of five in FIG. 23) arranged along the Y-axis direction so as to correspond to each illumination area. Incident on system PL20. The light passing through the projection optical system PL20 forms an image of a pattern DP on a plate P2 supported in parallel to the XY plane via a plate holder (not shown) on a plate stage (not shown). That is, as described above, each of the projection optical units PL1 to PL5 is configured as an equal-magnification erecting system, so that trapezoidal exposures arranged in the Y-axis direction so as to correspond to the illumination areas on the plate P2. An equal-magnification erect image of the pattern DP is formed in the region.
[0148]
Referring back to FIG. 23, the above-described mask stage MS is provided with a scanning drive system (not shown) having a long stroke for moving the mask stage MS along the X-axis direction that is the scanning direction. In addition, a pair of alignment drive systems (not shown) are provided for moving the mask stage MS by a minute amount along the Y-axis direction, which is the direction orthogonal to the scan, and rotating the mask stage MS by a minute amount around the Z-axis. The position coordinate of the mask stage MS is measured and controlled by a laser interferometer (not shown) using the moving mirror 125. Further, the mask stage MS is configured such that the position in the Z direction is variable.
[0149]
A similar drive system is also provided for the plate stage. That is, a scanning drive system (not shown) having a long stroke for moving the plate stage along the X-axis direction, which is the scanning direction, and moving the plate stage by a minute amount along the Y-axis direction, which is the orthogonal direction of scanning. In addition, a pair of alignment drive systems (not shown) are provided for rotating by a minute amount around the Z axis. The position coordinate of the plate stage is measured and controlled by a laser interferometer (not shown) using a movable mirror 126. Similarly to the mask stage MS, the plate stage is also configured to be movable in the Z direction. The positions of the mask stage MS and the plate stage in the Z direction are controlled by the main control system 120.
[0150]
The above-described projection optical units PL1, PL3, and PL5 are arranged as a first row at a predetermined interval in a direction orthogonal to the scanning direction. Similarly, the projection optical system units PL2 and PL4 are arranged in the second row with a predetermined interval in a direction orthogonal to the scanning direction. Between the projection optical unit in the first row and the projection optical unit in the second row, an off-axis alignment system 152 for aligning the plate P and an auto for focusing the mask M2 and the plate P2 are provided. A focus system 154 is arranged. The telecentricity adjustment and the focus adjustment in the off-axis alignment system 152 can be adjusted by the methods according to the first to seventh embodiments described above.
[0151]
In addition, an illuminance measurement unit 129 for measuring the illuminance of light irradiated on the plate P2 via the projection optical system PL20 is provided on the plate stage, and light (image) irradiated on the plate P2 An aerial image measuring device 124 is provided for measuring the spatial distribution.
[0152]
FIG. 25 is a diagram showing a configuration of the projection optical unit PL1 according to the embodiment of the present invention. The configuration of the projection optical units PL2 to PL5 is the same as that of PL1. The projection optical unit PL1 shown in the figure has a first imaging optical system K1 that forms a primary image of the mask pattern based on the light from the mask M2, and an erect image (second image) of the mask pattern based on the light from the primary image. And a second imaging optical system K2 that forms a next image) on a glass substrate (plate) P2. Note that, in the vicinity of the primary image formation position of the mask pattern, a field area (illumination area) of the projection optical unit PL1 on the mask M2 and a projection area (exposure area) of the projection optical unit PL1 on the glass substrate P are defined. A field stop FS is provided.
[0153]
The first imaging optical system K1 is a first deflection that is obliquely provided at an angle of 45 ° with respect to the mask surface (XY plane) so that light incident along the −Z direction from the mask M2 is reflected in the + X direction. A first reflecting surface P1r of a member (first deflection member) is provided. The first imaging optical system K1 includes, in order from the first reflecting surface P1r side, a first refractive optical system G1P having a positive refractive power, and a first concave reflecting mirror having a concave surface facing the first reflecting surface P1r side. MI1. The first refractive optical system G1P and the first concave reflecting mirror MI1 are disposed along the X direction, and constitute the first catadioptric optical system HK1 as a whole. Further, the first imaging optical system K1 has an angle of 45 ° with respect to the mask surface (XY plane) so as to reflect the light incident along the −X direction from the first catadioptric optical system HK1 in the −Z direction. The second reflecting surface P2r of the second deflecting member (third deflecting member) that is obliquely provided is provided. A first aperture stop AS1 is disposed adjacent to the first concave reflecting mirror MI1 in the first imaging optical system K1.
[0154]
On the other hand, the second imaging optical system K2 is inclined at an angle of 45 ° with respect to the glass substrate surface (XY plane) so that light incident along the −Z direction from the second reflecting surface P2r is reflected in the + X direction. A third reflecting surface P3r of the provided third deflecting member (fourth deflecting member) is provided. The second imaging optical system K2 includes, in order from the third reflecting surface P3r side, a second refractive optical system G2P having a positive refractive power and a second concave reflecting mirror having a concave surface directed to the third reflecting surface P3r side. MI2. The second refractive optical system G2P and the second concave reflecting mirror MI2 are arranged along the X direction, and constitute a second catadioptric optical system HK2 as a whole. Further, the second imaging optical system K2 is 45 ° with respect to the glass substrate surface (XY plane surface) so as to reflect the light incident along the −X direction from the second catadioptric optical system HK2 in the −Z direction. The fourth reflecting surface P4r of the fourth deflecting member (second deflecting member) inclined at an angle of is provided. A second aperture stop AS2 is disposed adjacent to the second concave reflecting mirror MI2 in the second imaging optical system K2. The second concave reflecting mirror MI2 is configured to be able to change the direction of the concave reflecting surface. That is, the direction of the reflecting surface can be changed by changing the thickness of the washer for attaching the second concave reflecting mirror MI2 to the housing or the like.
[0155]
A magnification adjusting member 144 is provided in the optical path between the fourth reflecting surface P4r of the fourth deflecting member and the glass substrate P. The magnification adjusting member 144 also functions as a distortion adjusting member and an image plane adjusting member. Furthermore, it also functions as a decentration aberration adjusting member for adjusting decentration distortion, decentered image surface aberration, decentration coma aberration, and decentration chromatic aberration.
[0156]
Further, the magnification adjustment by the magnification adjustment member 144, the distortion adjustment by the magnification adjustment member 144 that functions as a distortion adjustment member, the image surface adjustment by the magnification adjustment member 144 that functions as an image surface adjustment member, and the magnification adjustment member that functions as an eccentric aberration adjustment member A pair of wedge-shaped declination prism pairs 140 in the optical path between the mask M2 and the first reflecting surface P1r of the first deflecting member in order to correct the image shift in the XYZ directions caused by the decentration aberration adjustment by 144; And a plane parallel plate 142 constituting an image shifter. Here, the declination prism pair 140 constitutes a focal position correcting means for correcting the imaging position. The plane parallel plate 142 constitutes an image shift means for correcting (shifting) the imaging position.
[0157]
As described above, the pattern formed on the mask M2 is illuminated with substantially uniform illuminance by illumination light (exposure light) from an illumination optical system generally used in this technical field. The light traveling along the −Z direction from the mask pattern formed in each illumination area on the mask M2 enters the first reflecting surface P1r via the declination prism pair 140 and the parallel plane plate 142, and the first The light is deflected by 90 ° by the reflecting surface P1r, and enters the first catadioptric optical system HK1 along the + X direction. The light incident on the first catadioptric optical system HK1 reaches the first concave reflecting mirror MI1 via the first refractive optical system G1P. The light reflected by the first concave reflecting mirror MI1 enters the second reflecting surface P2r along the −X direction again through the first refractive optical system G1P. The light that is deflected by 90 ° at the second reflecting surface P2r and travels along the −Z direction forms a primary image of the mask pattern in the vicinity of the field stop FS. The lateral magnification in the X direction of the primary image is +1 times, and the lateral magnification in the Y direction is -1.
[0158]
The light traveling along the −Z direction from the primary image of the mask pattern is deflected by 90 ° by the third reflecting surface P3r and enters the second catadioptric optical system HK2 along the + X direction. The light incident on the second catadioptric optical system HK2 reaches the second concave reflecting mirror MI2 via the second refractive optical system G2P. The light reflected by the second concave reflecting mirror MI2 enters the fourth reflecting surface Pr4 along the −X direction again via the second refractive optical system G2P. The light that is deflected by 90 ° on the fourth reflecting surface Pr4 and travels along the −Z direction forms a secondary image of the mask pattern in the corresponding exposure region on the glass substrate P2 via the magnification adjusting member 144. . Here, the lateral magnification in the X direction and the lateral magnification in the Y direction of the secondary image are both +1 times. That is, the mask pattern image formed on the glass substrate P2 via the projection optical unit PL1 is a 1 × erect image, and the projection optical unit PL1 constitutes a 1 × erect system.
[0159]
In the first catadioptric optical system HK1 described above, the first aperture stop AS1 and the first concave reflecting mirror MI1 are disposed at the rear focal position of the first refractive optical system G1P. Telecentric on the FS side. Also in the second catadioptric optical system HK2, since the second aperture stop AS2 and the second concave reflecting mirror MI2 are disposed at the rear focal position of the second refractive optical system G2P, the field stop FS side and the glass substrate are arranged. Telecentric on the P2 side. As a result, the projection optical unit PL1 is a telecentric optical system on both sides (the mask M2 side and the glass substrate P2 side).
[0160]
As described above, the mask pattern image formed on the glass substrate P2 via the projection optical unit PL1 is an equal-size erect image. Therefore, desired scanning exposure can be performed by moving the mask M2 held on the mask stage MS and the glass substrate P2 held on the substrate stage integrally along the same direction (X direction). it can.
[0161]
Now, in the projection optical system PL1 according to the eighth embodiment shown in FIG. 25, the second concave reflecting mirror MI2 is formed of a light-transmitting material such as low-expansion glass or quartz glass. A dielectric film having a reflectivity of about 99% is deposited on the reflecting surface of the two concave reflecting mirror MI2. Therefore, about 1% of exposure light passes to the back surface side (+ X direction side) of the second concave reflecting mirror MI2. Here, since the reflecting surface of the concave reflecting mirror is a pupil conjugate surface, an image of the secondary light source is formed on this reflecting surface. When the back surface of the second concave reflecting mirror MI2 is a smooth surface (polished surface), a secondary light source can be visually observed from the back surface side of the second concave reflecting mirror MI2 by placing a diffusion plate or thin paper on the back surface. The image can be observed. If the back surface of the second concave reflecting mirror MI2 is like a diffusing surface, the image of the secondary light source can be observed as it is.
[0162]
For this reason, in the eighth embodiment, a diffusing plate is arranged on the illumination optical system IL side with respect to the mask pattern surface, and the illumination light is supplied to the projection optical system PL20 so that the sigma value σ ≧ 1. . At this time, the diffusion plate diffuses so that the image of the aperture stop 113 (or the image of the secondary light source formed by the fly-eye integrator 112) and the aperture stop AS2 can be simultaneously observed on the reflection surface of the second concave reflecting mirror MI2. Set the degree.
[0163]
Then, while observing the positional relationship between the aperture stop AS2 and the light source (secondary light source image), the fly-eye integrator 112 and the aperture stop AS2 and the light source (secondary light source image) are substantially concentric. The telecentricity is adjusted by adjusting the position of the aperture stop 113. At this time, since the image of the aperture stop AS1 adjacent to the first concave reflector MI1 is also formed on the reflection surface of the second concave reflector MI2, the positional relationship of the aperture stop AS1 with respect to the aperture stop AS2 is also confirmed. It is possible.
[0164]
In the eighth embodiment, the example of adjusting the telecentricity of the projection optical system having the two catadioptric imaging optical systems K1 and K2 has been described. A catadioptric projection optical system comprising the above refractive imaging optical system, a catadioptric projection optical system comprising only one catadioptric imaging optical system, and further a reflective projection optical system It is possible to adjust the telecentricity.
[0165]
In the exposure apparatuses according to the fifth to eighth embodiments described above, the reticle (mask) is illuminated by the illumination device (illumination process), and the transfer pattern formed on the mask using the projection optical system is photosensitive. Microdevices (semiconductor elements, imaging elements, liquid crystal display elements, thin film magnetic heads, etc.) can be manufactured by exposing the substrate (exposure process). Hereinafter, an example of a technique for obtaining a semiconductor device as a microdevice by forming a predetermined circuit pattern on a plate or the like as a photosensitive substrate using the exposure apparatus according to the fifth to eighth embodiments. This will be described with reference to the flowchart of FIG.
[0166]
First, in step 301 of FIG. 26, a metal film is deposited on one lot of plates. In the next step 302, a photoresist is applied on the metal film on the one lot of plates. Thereafter, in step 303, using the exposure apparatus including the FIA microscope according to the fifth to eighth embodiments, the image of the pattern on the mask is formed on the one lot of plates via the projection optical system. The exposure is sequentially transferred to each shot area. Thereafter, in step 304, the photoresist on the one lot of plates is developed, and in step 305, the resist pattern is etched on the one lot of plates to form a pattern on the mask. Corresponding circuit patterns are formed in each shot area on each plate.
[0167]
Thereafter, a device pattern such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer. According to the semiconductor device manufacturing method described above, a semiconductor device having an extremely fine circuit pattern can be obtained with high throughput. In steps 301 to 305, a metal is vapor-deposited on the plate, a resist is applied on the metal film, and exposure, development, and etching processes are performed. Prior to these processes, the process is performed on the plate. It is needless to say that after forming a silicon oxide film, a resist may be applied on the silicon oxide film, and steps such as exposure, development, and etching may be performed.
[0168]
In the exposure apparatus according to the fifth to eighth embodiments, a liquid crystal display element as a micro device is obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). You can also. Hereinafter, an example of the technique at this time will be described with reference to the flowchart of FIG. In FIG. 27, in the pattern formation step 401, the mask pattern is transferred to a photosensitive substrate (such as a glass substrate coated with a resist) using an exposure apparatus equipped with FIA microscopes according to the fifth to eighth embodiments. A so-called photolithographic process of exposing is performed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes steps such as a developing step, an etching step, and a resist stripping step, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming step 402.
[0169]
Next, in the color filter forming step 402, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three of R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning line direction. Then, after the color filter forming step 402, a cell assembling step 403 is executed. In the cell assembly step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step 401, the color filter obtained in the color filter formation step 402, and the like. In the cell assembly step 403, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern formation step 401 and the color filter obtained in the color filter formation step 402, and a liquid crystal panel (liquid crystal cell) is obtained. ).
[0170]
Thereafter, in a module assembling step 404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, since exposure is performed using an exposure apparatus in which accurate alignment is performed by an image observation apparatus in which telecentricity adjustment and focus position measurement are performed, an extremely fine circuit pattern is formed. A liquid crystal display element having the above can be obtained with high throughput.
[0171]
【The invention's effect】
According to the telecentricity adjustment method of the image observation apparatus of the present invention, an image of the secondary light source imaged by the imaging element using an inexpensive tool such as an imaging element for performing the telecentricity adjustment of the image observation apparatus. The telecentricity adjustment of the image observation apparatus is performed by adjusting the position of the secondary light source based on the imaging aperture stop image. That is, before the image observation apparatus is mounted on the exposure apparatus, the telecentricity adjustment of the image observation apparatus can be performed by a simple method. Therefore, the cost for adjusting the telecentricity of the image observation apparatus can be reduced, and the telecentricity adjustment of the image observation apparatus can be performed easily and with high accuracy.
[0172]
Further, according to the focus position measurement method of the image observation apparatus of the present invention, a linear pattern is used, the spatial image intensity distribution of the linear pattern is measured, and based on the asymmetry of the measured spatial image intensity distribution, The focus position of the image observation apparatus is measured. Alternatively, the image position of the linear pattern is measured using the linear pattern, and the focus position of the image observation apparatus is measured based on the measured image position of the linear pattern. That is, the focus position can be measured by a simple method before the image observation apparatus is mounted on the exposure apparatus. Therefore, the time and cost for measuring the focus position of the image observation apparatus can be reduced, and the focus position measurement of the image observation apparatus can be performed easily and with high accuracy.
[0173]
Further, according to the exposure apparatus of the present invention, the image observation apparatus in which telecentricity adjustment or focus position measurement is precisely performed by the method of the present invention is provided. Therefore, since the mask and the photosensitive substrate are aligned based on the position of the mask and the photosensitive substrate accurately measured by the image observation apparatus, a fine exposure pattern can be satisfactorily exposed.
[0174]
Further, according to the focus position measurement method of the projection optical system of the present invention, a linear pattern is used, the aerial image intensity distribution of the linear pattern is measured, and based on the asymmetry of the measured aerial image intensity distribution, Measure the focus position of the projection optical system. Alternatively, a linear pattern is used, the image position of the linear pattern is measured, and the focus position of the projection optical system is measured based on the measured image position of the linear pattern. Therefore, it is possible to reduce time and cost for measuring the focus position of the projection optical system, and it is possible to easily and accurately measure the focus position of the projection optical system.
[Brief description of the drawings]
FIG. 1 is a diagram showing an FIA microscope and a tool for performing telecentricity adjustment of the FIA microscope according to a first embodiment of the present invention.
FIG. 2 is a flowchart for explaining a telecentricity adjustment method for the FIA microscope according to the first embodiment of the present invention;
FIG. 3 is a diagram illustrating a state where an exit end image and an aperture stop image of the light guide according to the first embodiment are captured.
FIG. 4 is a flowchart for explaining a telecentricity adjustment method for an FIA microscope according to a second embodiment of the present invention;
FIG. 5 is a diagram showing an FIA microscope and a tool for performing telecentricity adjustment of the FIA microscope according to a second embodiment of the present invention.
FIG. 6 is a flowchart for explaining a focus position measuring method for an FIA microscope according to a third embodiment of the present invention;
FIG. 7 is a diagram for explaining focus position measurement of an FIA microscope according to a third embodiment of the present invention.
FIG. 8 is a diagram illustrating a state where an exit end image and an aperture stop image of a light guide according to a third embodiment are captured.
FIG. 9 is a diagram showing a linear pattern of indices according to a third embodiment.
FIG. 10 is a graph showing an aerial image intensity distribution of an index according to the third embodiment and a differential value thereof.
FIG. 11 is a graph showing a T value determined based on an aerial image intensity distribution according to the third embodiment.
FIG. 12 is a graph showing a T value determined based on an aerial image intensity distribution when spherical aberration remains in the FIA microscope according to the third embodiment.
FIG. 13 is a graph showing a contrast value when spherical aberration remains in the FIA microscope according to the third embodiment.
FIG. 14 is a graph showing a T value determined based on an aerial image intensity distribution when coma aberration remains in the FIA microscope according to the third embodiment.
FIG. 15 is a flowchart for explaining a focus position measuring method for an FIA microscope according to a fourth embodiment of the present invention;
FIG. 16 is a diagram illustrating a state where an exit end image and an aperture stop image of a light guide of an FIA microscope are captured.
FIG. 17 is a view showing the arrangement of an exposure apparatus according to the fifth embodiment of the present invention.
FIG. 18 is a flowchart for explaining a focus position measuring method for a projection optical system according to a fifth embodiment of the invention;
FIG. 19 is a diagram for explaining a configuration of a σ stop according to a fifth embodiment;
FIG. 20 is a flowchart for explaining a focus position measuring method for a projection optical system according to a sixth embodiment of the present invention;
FIG. 21 is a flowchart for explaining a defocus amount measuring method of an FIA microscope according to a seventh embodiment of the present invention;
FIG. 22 is a diagram showing a configuration of an FIA microscope according to a seventh embodiment of the present invention.
FIG. 23 is a perspective view showing an overall schematic configuration of a scanning exposure apparatus according to an eighth embodiment of the present invention.
FIG. 24 is a side view of an illumination optical system configuration according to an eighth embodiment.
FIG. 25 is a diagram showing the configuration of each projection optical unit according to the eighth embodiment.
FIG. 26 is a flowchart of a method of manufacturing a semiconductor device as a micro device according to an embodiment.
FIG. 27 is a flowchart of a method of manufacturing a liquid crystal display element as a micro device according to an embodiment.
FIG. 28 is a diagram showing a configuration of a conventional FIA microscope.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Light source, 4 ... Collector lens, 6 ... Wavelength selection filter, 8 ... Condenser lens, 10 ... Light guide, 12 ... σ stop, 14 ... Field stop, 16 ... Condenser lens, 18 ... Half mirror, 20 ... Aperture stop, 22 ... first objective lens, 24 ... second objective lens, 26 ... reflecting mirror, 28,34 ... CCD, 30 ... tool mirror, 32,40 ... tool lens, 42 ... reflecting plate, 48 ... index, 72 ... elliptical mirror 72 ... light source 74 ... dichroic mirror 76 ... relay lens 78 ... fly eye lens 80 ... sigma aperture 82 ... condenser lens 84 ... collimator lens 86 ... reflecting mirror 90,92 ... FIA microscope 94 ... AIS, 124: aerial image measuring device, 125, 126 ... moving mirror, 129 ... illuminance measuring unit, 152 ... alignment system, 154 ... autofocus system, IL ... illumination optical system, M, M2 ... mask, PL, PL20 ... projection optical system, PL1-PL5 ... projection optical unit, P, P2 ... plate.

Claims (19)

An image observation apparatus for guiding light from a predetermined secondary light source to an observation object and forming an image of the observation object on an imaging surface of an image sensor based on light from the observation object via an objective optical system In the telecentricity adjustment method of
A secondary light source image forming step of forming an image of the predetermined secondary light source on a predetermined surface based on light from the predetermined secondary light source via the objective optical system;
An imaging that forms an image of an imaging aperture stop disposed between the objective optical system and the imaging element on the predetermined surface based on light from the predetermined secondary light source via the objective optical system Aperture stop image forming process;
A telecentricity adjustment method for an image observation apparatus, comprising: an adjustment step of adjusting a position of the predetermined secondary light source based on both the image of the secondary light source and the image of the imaging aperture stop. . An imaging step of arranging an imaging surface of an imaging device different from the imaging device on the predetermined surface and capturing both the image of the secondary light source and the image of the imaging aperture stop;
In the imaging aperture stop image forming step, an image of the imaging aperture stop is formed based on light from the predetermined secondary light source through both the imaging aperture stop and the objective optical system,
The position of the secondary light source is adjusted in the adjusting step based on the image of the secondary light source and the image of the imaging aperture stop imaged in the imaging step. Telecentricity adjustment method of the image observing apparatus. A tool optical system arranging step of arranging a tool optical system in an optical path between the objective optical system and the image sensor;
An imaging surface arrangement step of positioning the imaging surface of the imaging element at a focal position of the tool optical system;
An image capturing step of capturing an image of the secondary light source and an image of an imaging aperture stop disposed between the objective optical system and the image sensor using the image sensor;
The position of the secondary light source is adjusted in the adjusting step based on the image of the secondary light source and the image of the imaging aperture stop imaged in the imaging step. Telecentricity adjustment method of the image observing apparatus. The method further includes a step of moving the position of the secondary light source along the optical axis direction so that the image of the predetermined secondary light source and the image of the imaging aperture stop are formed on the predetermined surface. The telecentricity adjustment method of the image observation apparatus as described in any one of Claim 1 thru | or 3. The image observation according to any one of claims 1 to 4, further comprising a step of inserting a diffuser plate in an optical path between the predetermined secondary light source and the imaging aperture stop. Device telecentricity adjustment method. 6. The telecentricity adjustment method for an image observation apparatus according to claim 5, wherein the diffusivity of the diffusion plate is determined so that an image of the secondary light source can be discriminated on the predetermined plane. The adjustment step adjusts the position of the predetermined secondary light source so that the image of the predetermined secondary light source and the image of the imaging aperture stop are concentric. The telecentricity adjustment method of the image observation apparatus as described in any one of Claims 6. The adjusting step adjusts a position of a light guide end surface for forming the predetermined secondary light source or a position of an illumination σ stop for forming the predetermined secondary light source based on light from a light source. The telecentricity adjustment method for an image observation apparatus according to claim 1, wherein: An image observation apparatus for guiding light from a predetermined secondary light source to an observation object and forming an image of the observation object on an imaging surface of an image sensor based on light from the observation object via an objective optical system In the focus position measurement method of
An illumination light eccentric step for decentering the predetermined secondary light source in a predetermined eccentric direction with respect to the optical axis of the image observation device;
A pattern placement step of positioning a linear pattern extending in a direction perpendicular to the eccentric direction in the vicinity of the surface on which the observation object is placed or in the vicinity of a surface conjugate with the placed surface;
An aerial image intensity distribution measuring step for measuring an aerial image intensity distribution of the linear pattern;
A focus position measuring step of measuring a focus position of the objective optical system based on asymmetry of the aerial image intensity distribution measured in the aerial image intensity distribution measuring step. Focus position measurement method. An image position measuring step of measuring an image position of the linear pattern;
The focus position measuring step is based on the asymmetry of the aerial image intensity distribution measured in the aerial image intensity distribution measuring step and the image position of the linear pattern measured in the image position measuring step. The focus position measuring method of the image observation apparatus according to claim 9, wherein the focus position is measured. An image observation apparatus for guiding light from a predetermined secondary light source to an observation object and forming an image of the observation object on an imaging surface of an image sensor based on light from the observation object via an objective optical system In the focus position measurement method of
An illumination light eccentric step for decentering the predetermined secondary light source in a predetermined eccentric direction with respect to the optical axis of the image observation device;
A pattern placement step of positioning a linear pattern extending in a direction perpendicular to the eccentric direction in the vicinity of the surface on which the observation object is placed or in the vicinity of the surface conjugate with the placed surface;
A measurement step of measuring the image position of the linear pattern;
And a focus position measuring step of measuring a focus position of the objective optical system based on the image position of the linear pattern measured in the measuring step. In the illumination light eccentric step, the position of the light guide end surface for forming the predetermined secondary light source based on the light from the light source, or the position of the illumination σ stop for forming the predetermined secondary light source The focus position measuring method for an image observation apparatus according to claim 9, further comprising a step of decentering along an eccentric direction. The image observation according to any one of claims 9 to 12, wherein the illumination light decentering step further includes a step of replacing an illumination σ stop for forming the predetermined secondary light source. Device focus position measurement method. The focus position measurement method for an image observation apparatus according to claim 9, wherein the linear pattern is a phase pattern. An exposure apparatus comprising: an image observation apparatus that adjusts telecentricity by the telecentricity adjustment method according to claim 1. An exposure apparatus comprising: an image observation apparatus that measures a focus position by the focus position measurement method according to any one of claims 9 to 14. In a focus position measuring method of a projection optical system for projecting a pattern image formed on a mask arranged on a first surface onto a photosensitive substrate arranged on a second surface,
An illumination light decentering step of decentering a predetermined secondary light source in a predetermined eccentric direction with respect to the optical axis of the projection optical system;
An illuminating step for guiding the eccentric light from the secondary light source to the first surface;
A pattern placement step of positioning a linear pattern extending in a direction perpendicular to the eccentric direction in the vicinity of the first surface or in the vicinity of a surface conjugate with the first surface;
An aerial image intensity distribution measuring step for measuring an aerial image intensity distribution of the linear pattern;
A focus position measuring step of measuring a focus position of the projection optical system based on asymmetry of the aerial image intensity distribution measured in the aerial image intensity distribution measuring step. Focus position measurement method. An image position measuring step of measuring the image position of the linear pattern;
In the focus position measurement step, based on the asymmetry of the aerial image intensity distribution measured in the aerial image intensity distribution measurement step and the image position of the linear pattern measured in the image position measurement step, the projection optical system The focus position measuring method for a projection optical system according to claim 17, wherein the focus position is measured. In a focus position measuring method of a projection optical system for projecting a pattern image formed on a mask arranged on a first surface onto a photosensitive substrate arranged on a second surface,
An illumination light decentering step of decentering a predetermined secondary light source in a predetermined eccentric direction with respect to the optical axis of the projection optical system;
An illuminating step for guiding the eccentric light from the secondary light source to the first surface;
A pattern placement step of positioning a linear pattern extending in a direction perpendicular to the eccentric direction in the vicinity of the first surface or in the vicinity of a surface conjugate with the first surface;
A measurement step of measuring the image position of the linear pattern;
A focus position measurement method for a projection optical system, comprising: a focus position measurement step for measuring a focus position of the projection optical system based on an image position of the linear pattern measured in the measurement step.

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