Patent Publication Number: US-2022216119-A1

Title: Surface position detection device, exposure apparatus, substrate-processing system, and device-manufacturing method

Description:
TECHNICAL FIELD 
     The present invention relates to a surface position detection device, an exposure apparatus, a substrate-processing system, and a device-manufacturing method. 
     BACKGROUND 
     In an exposure apparatus in which a pattern formed on a mask is projected and exposed onto a photosensitive substrate via a projection optical system, a depth of focus of the projection optical system is relatively shallow, and an exposed surface (surface: transfer surface) of the photosensitive substrate may not be flat. Therefore, in the exposure apparatus, it is necessary to accurately perform position alignment of a surface of the photosensitive substrate relative to an image surface (imaging surface) of the projection optical system. 
     For example, an oblique-incidence-type surface position detection device is known as a device that detects a surface position (surface position of the exposed surface) of the photosensitive substrate along an optical axis direction of the projection optical system (refer to Patent Document 1). 
     RELATED ART DOCUMENTS 
     Patent Document 
     
         
         [Patent Document 1] United States patent application, Publication No. 2010/0231881 
       
    
     SUMMARY OF INVENTION 
     A surface position detection device of a first aspect of the present invention is a surface position detection device that obtains position information of a detected surface along an axis that intersects the detected surface, the surface position detection device including: a light transmission unit by which a plurality of detection lights having a smoothly modulated intensity in the detected surface in a first direction within the detected surface are radiated and superimposed onto the detected surface obliquely from a direction having a direction component in the first direction and which forms an irradiation region on the detected surface; a light reception unit that has a light detection portion having a light reception surface arranged at an optically conjugated position with respect to the detected surface, receives at a different position of each light reception surface, the plurality of detection lights reflected by a detection region of which a width in the first direction is a predetermined value in the irradiation region, and outputs each photoelectric conversion signal of the plurality of detection lights; and a calculation unit that calculates position information of the detected surface based on the photoelectric conversion signal of the plurality of detection lights output from the light reception unit. 
     A surface position detection device of a second aspect of the present invention obtains position information of a detected surface along an axis that intersects the detected surface, the surface position detection device including: a light transmission unit by which a plurality of detection lights having a modulated intensity in the detected surface in a first direction within the detected surface are radiated and superimposed onto the detected surface obliquely from a direction having a direction component in the first direction and which forms an irradiation region on the detected surface; a light reception unit that has a light detection portion having a light reception surface arranged at an optically conjugated position with respect to the detected surface, receives at a different position of the light reception surface, each of the plurality of detection lights reflected by a detection region of which a width in the first direction is a predetermined value in the irradiation region, and outputs each photoelectric conversion signal of the plurality of detection lights; and a calculation unit that calculates position information of the detected surface based on the photoelectric conversion signal of the plurality of detection lights output from the light reception unit, wherein a width of a third direction having an imaging relationship with the first direction of an image of the detection region in the light reception surface is narrower than a width of a fourth direction that intersects the third direction in the light reception surface. 
     An exposure apparatus of a third aspect of the present invention includes: a projection optical system; a substrate stage on which a substrate is mounted and which moves the substrate; and a surface position detection device of the first aspect or the second aspect that detects a position of a surface of the substrate as the detected surface. 
     A device-manufacturing method of a fourth aspect of the present invention includes: forming a resist on a surface of a substrate; detecting a position of a surface of the resist formed on the surface of the substrate using the exposure apparatus of the third aspect, setting the surface of the resist at a predetermined position in the optical axis direction of the projection optical system, and exposing an exposure pattern; developing the resist; and processing the surface of the substrate based on a resist pattern formed by the developing. 
     A substrate-processing system of a fifth aspect of the present invention is a system in which a substrate is a processing target, the substrate-processing system including: a measurement device having a first stage on which the substrate is mounted and the surface position detection device of the first aspect or the second aspect that measures a position in a direction which intersects the surface of a plurality of points on a surface of the substrate; and an exposure apparatus that includes a second stage on which the substrate for which the measurement by the measurement device has been completed is mounted and that exposes the substrate which is mounted on the second stage, wherein the exposure apparatus performs the exposure while changing a position in the direction which intersects the substrate using at least a measurement result by the measurement device. 
     A device-manufacturing method of a sixth aspect of the present invention includes: forming a resist on a surface of a substrate; detecting a position in a direction which intersects the surface of a plurality of points in a surface of the resist formed on the surface of the substrate and exposing an exposure pattern while changing the position of the surface of the resist in the direction which intersects the surface based on the detected position of the plurality of points using the substrate-processing system of the fifth aspect; and forming a circuit pattern based on the exposure pattern. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view schematically showing a configuration of a surface position detection device  100  of a first embodiment. 
         FIG. 2  is a side view of a configuration of a portion of the surface position detection device  100  when seen from a −Y direction. 
         FIG. 3  is a top view of a configuration of a portion of the surface position detection device  100  when seen from a +Z direction. 
         FIG. 4  is a view showing an example of a detection light division member. 
         FIG. 5 ( a )  is a view showing an irradiation region IA on a detected surface WA, and  FIG. 5 ( b )  is a view showing a light amount distribution in an X-axis direction of the irradiation region IA. 
         FIG. 6  is a view of an incident surface  23   a  of a light reception prism  23  when seen from a normal direction with respect to the incident surface  23   a.    
         FIG. 7  is a view showing an example of a compound separation member  25 . 
         FIG. 8  is a view showing an image of a P-polarization component of an opening portion SL formed on the light reception surface  29   a.    
         FIG. 9  is a view showing an example of a relationship between a position (horizontal axis) in a Z-axis direction of the detected surface WA, and a photoelectric conversion signal S 1   b  and a photoelectric conversion signal S 2   b.    
         FIG. 10 ( a )  is a perspective view showing a detection light division member of another example, and  FIG. 10 ( b )  is a view of the detection light division member of another example when seen from a light transmission-side first lens  17  side. 
         FIG. 11 ( a )  is a view representing a light amount distribution of first detection light, second detection light, and third detection light on the detected surface WA in a surface position detection device of a second embodiment, and  FIG. 11 ( b )  is a view showing a relationship between a position (horizontal axis) in a Z-axis direction of the detected surface WA and a photoelectric conversion signal. 
         FIG. 12  is a view schematically showing an exposure apparatus  200  of a third embodiment. 
         FIG. 13  is a view schematically showing a substrate-processing line that includes a substrate-processing system  300  of a fourth embodiment. 
         FIG. 14  is a view showing an outline of a device-manufacturing method. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the present specification, “optically conjugated” means that one surface and another surface have an imaging relationship via an optical system. 
     In the present specification, “imaging relationship” means a relationship in which light emitted from an arbitrary one point in one region is focused in a range of about the resolution of an optical system centered at one point in another region via the optical system. 
     In the present specification, “sinusoidal function” means a function in which a predetermined constant is added to a sine function (sin) or a cosine function (cos), and all values are non-negative. 
     (Surface Position Detection Device of First Embodiment) 
       FIG. 1  is a view schematically showing a configuration of a surface position detection device  100  of a first embodiment. In  FIG. 1 , a Z-axis is set in a direction (normal direction) perpendicular to a surface (hereinafter, also referred to as a “detected surface”) WA of a measured object W mounted on the surface position detection device  100 , an X-axis is set to be parallel to a paper plane of  FIG. 1  within a plane perpendicular to the Z-axis, that is, within a plane parallel to the detected surface WA, and a Y-axis is set to be perpendicular to the paper plane of  FIG. 1 . 
     An outline of a path of detection light in the surface position detection device  100  of the first embodiment is described. The detection light is supplied to a light introduction portion  12 , for example, from a light source  10  via a light guide  11 . A wavelength band of the detection light from the light source  10  is, as an example, 400 nm to 800 nm, but is not limited thereto. For example, the wavelength band may be 400 nm or less and be, as an example, near 200 nm, or may be an infrared band of 800 nm or more and be, as an example, 1200 nm to 1700 nm. The detected surface WA is irradiated with the detection light emitted from the light introduction portion  12  via a condenser lens group  13 , a diffraction grating plate  14 , a light transmission-side second lens group  15 , a light transmission-side first lens group  17 , a mirror  18 , and the like. The detection light reflected by the detected surface WA reaches a light reception prism  23  via a mirror  19 , a light reception-side first lens group  20 , a light reception-side second lens group  22 , and the like. The detection light refracted by the light reception prism  23  enters a polarization separation prism  27  via a relay optical system constituted of a front-side lens group  24  and a rear-side lens group  26 . Then, the detection light is separated into two different polarization components at the polarization separation prism  27 , and one of the separated detection lights enters a light reception surface  29   a  of a light detection portion  28   a  and the other enters a light reception surface  29   b  of a light detection portion  28   b.    
     In  FIG. 1  to  FIG. 3 , only one lens of each lens group is shown in the drawings, but each lens group may be constituted of one or more lenses. 
     The measured object W is mounted on a stage ST, and the XYZ position of the stage ST is measured by an interferometer or an encoder (not shown). 
     In the present specification, all or part of the light introduction portion  12 , the condenser lens group  13 , the diffraction grating plate  14 , the light transmission-side second lens group  15 , a detection light division member  16 , the light transmission-side first lens group  17 , and the mirror  18  are also collectively referred to as a light transmission unit TS. 
     In the present specification, all or part of the mirror  19 , the light reception-side first lens group  20 , a cylindrical lens  21 , the light reception-side second lens group  22 , the light reception prism  23 , the relay optical system ( 24 ,  26 ), a compound separation member  25 , the polarization separation prism  27 , and the light detection portions  28   a  and  28   b  are also collectively referred to as a light reception unit RS. 
       FIG. 2  and  FIG. 3  are views schematically showing a configuration of a portion of the surface position detection device  100  shown in  FIG. 1 .  FIG. 2  is a side view of a configuration from the condenser lens group  13  to the light detection portion  28   a  when seen from a −Y direction. In  FIG. 2 , an optical path from the diffraction grating plate  14  to the detected surface WA and an optical path from the detected surface WA to the light reception prism  23  are linearly deployed.  FIG. 3  is a top view of a configuration from the condenser lens group  13  to the light detection portion  28   a  when seen from a +Z direction. In  FIG. 2  and  FIG. 3 , the mirrors  18  and  19 , the polarization separation prism  27 , and the light detection portion  28   b  are omitted from the drawings. Further, in  FIG. 2  and  FIG. 3 , an optical axis AX 2  is matched with an optical axis AX 3 , an optical axis AX 4  is matched with an optical axis AX 5 , and an optical axis AX 6  is matched with the X-axis direction. 
     The light emitted from the light introduction portion  12  enters the condenser lens group  13  and enters the diffraction grating plate  14  substantially along an optical axis AX 1  of the condenser lens group  13 . A diffraction grating  14   a  constituted of a dielectric film or a metal film is formed on a surface of the diffraction grating plate  14 . The diffraction grating  14   a  is, as an example, a one-dimensional grating in which a substantially rectangular pattern having a longitudinal direction matched with the Y direction in the drawing is aligned at a predetermined period in an in-plane direction of the diffraction grating plate  14  perpendicular to the Y direction. In the present example, the diffraction grating  14   a  is one that selectively generates+1st-order diffraction light DP and −1st-order diffraction light DM. 
     The ±1st-order diffraction lights DP and DM reflected and diffracted by the diffraction grating plate  14  enter the detection light division member  16  via the light transmission-side second lens  15 . The detection light division member  16  is arranged on a pupil surface TP of a light transmission optical system constituted of the light transmission-side second lens group  15  and the light transmission-side first lens group  17 . Here, the pupil surface TP is a plane on which a plurality of rays that enter different positions on the detected surface WA from the same direction are concentrated at approximately one point. Conversely, lights that travel in different directions from one point on the pupil surface TP enter different positions on the detected surface WA from the same direction. The optical axis AX 2  is an optical axis of the light transmission-side second lens group  15  and the light transmission-side first lens group  17  and is matched with the optical axis AX 1  of a condenser lens  13  reflected (mirrored) by the diffraction grating plate  14 . 
       FIG. 4  is a view showing an example of the detection light division member  16 .  FIG. 4 ( a )  is a perspective view showing the detection light division member  16 , and  FIG. 4 ( b )  is a view of the detection light division member  16  when seen from a light transmission-side first lens group  17  side. The optical axis AX 2  and the Y-axis of  FIG. 4  indicate the same direction as the optical axis AX 2  and the Y-axis shown in  FIG. 1  to  FIG. 3 . A z1-axis of  FIG. 4  indicates a direction perpendicular to the optical axis AX 2  and the Y-axis. The detection light division member  16  includes four prisms  16   a  to  16   d  as an example. The prism  16   a  and the prism  16   b  are arranged at substantially the same position in the optical axis AX 2  direction to be in contact with each other in the Y direction. The prism  16   c  and the prism  16   d  are arranged at positions away from the prism  16   a  and the prism  16   b  toward the downstream side of the optical path in the optical axis AX 2  direction to be in contact with each other in the Y direction. A boundary between the prism  16   a  and the prism  16   b  and a boundary between the prism  16   c  and the prism  16   d  are on a plane that passes through the optical axis AX 2  and is parallel to the z1 axis. 
     Any one of the four prisms  16   a  to  16   d  has a thickness in the optical axis AX 2  direction that is changed in accordance with the position in the z1 direction, provides the light transmitting therethrough with a phase difference that is changed in accordance with the position in the z1 direction, and deflects the proceeding direction of the light transmitting therethrough by a minute angle in the z1 direction. 
     The prisms  16   a  and  16   b , and the prisms  16   c  and  16   d  may not be two separate prisms, and may be a prism in which the shape of an incident surface or an emission surface of an integrated prism is different between a +Y side and a −Y side of the optical axis AX 2 . 
     The +1st-order diffraction light DP and the −1st-order diffraction light DM that enter the detection light division member  16  are divided at the pupil surface TP into first detection light DL 1  that is emitted from the prism  16   c  arranged on a further+Y side than the optical axis AX 2  and second detection light DL 2  that is emitted from the prism  16   d  arranged on a further −Y side than the optical axis AX 2 , respectively. Then, the first detection light DL 1  and the second detection light DL 2  are deflected from each other by a minute angle in the z1 direction. 
     It should be noted that both of the +1st-order diffraction light DP and the −1st-order diffraction light DM are included in each of the first detection light DL 1  and the second detection light DL 2 . 
     Further, a diffraction light selection filter that selectively transmits only the +1st-order diffraction light DP and the −1st-order diffraction light DM may be provided on one side or the other side in the optical axis AX 2  direction of the detection light division member  16 . In this case, a diffraction grating that generates diffraction light other than the +1st-order diffraction light DP and the −1st-order diffraction light DM may be used as the diffraction grating  14   a.    
     The first detection light DL 1  and the second detection light DL 2  are focused by the light transmission-side first lens group  17 , then are reflected by the mirror  18 , are radiated on the detected surface WA, and form an irradiation region IA on the detected surface WA. The first detection light DL 1  and the second detection light DL 2  are lights passing through a position that is displaced in the Y direction with respect to each other in the pupil surface TP. Accordingly, as shown in  FIG. 3 , an incident direction of the first detection light DL 1  and the second detection light DL 2  to the detected surface WA is a direction almost parallel to the +X direction but is displaced in the Y direction with respect to each other. 
     An incident angle θ (an angle of incident light with respect to a normal line NV of the detected surface WA) of the detection light to the detected surface WA is set to, for example, a large angle equal to or more than 80 degrees and less than 90 degrees. The optical axis AX 3  is a reflected (mirrored) axis of the optical axis AX 2  by the mirror  18 . The incident angle θ may be less than 80 degrees or may be equal to or more than 90 degrees. 
       FIG. 5 ( a )  is a view showing the irradiation region IA on the detected surface WA, and  FIG. 5 ( b )  is a view showing a light amount distribution in the X-axis direction of the irradiation region IA. A solid line represents a light amount distribution IDL 1  of the first detection light DL 1 , and a dashed line represents a light amount distribution IDL 2  of the second detection light DL 2 . A detection region DA shown in  FIG. 5  will be described later. 
     Since each of the first detection light DL 1  and the second detection light DL 2  is constituted of two diffraction lights which are the +1st-order diffraction light DP and the −1st-order diffraction light DM, both of the light amount distribution IDL 1  and the light amount distribution IDL 2  form an interference fringe formed of two diffraction lights. Accordingly, as shown in  FIG. 5 ( b ) , both the light amount distribution IDL 1  and the light amount distribution IDL 2  define a distribution in which the intensity is modulated by a sinusoidal function (sine function) having an amplitude and a predetermined period FX in the X direction. In the present example, the period FX in the X direction and the amplitude of the sinusoidal function that modulates the light amount distribution IDL 1  are equal to those that modulate the light amount distribution IDL 2 . 
     The first detection light DL 1  and the second detection light DL 2  are deflected by a minute angle by the detection light division member  16  as described above. According to this deflection, the phase of the sinusoidal functions of the light amount distribution IDL 1  and the light amount distribution ID are displaced by half of the period FX of the sinusoidal function of each intensity modulation. However, since the deflection amount is small, the first detection light DL 1  and the second detection light DL 2  are superimposed, that is, are almost overlapped with each other and are radiated onto the irradiation region IA on the detected surface WA. 
     In other words, the first detection light DL 1  and the second detection light DL 2  are radiated and superimposed onto the detected surface WA obliquely from a direction having a direction component in the +X direction and form the irradiation region IA on the detected surface WA. 
     Accordingly, in the irradiation region IA, at an arbitrary position in the X-axis direction, the sum of the light amount of the first detection light DL 1  and the light amount of the second detection light DL 2  is constant. In other words, the light amount distribution IDL 1  and the light amount distribution IDL 2  are complementary with respect to the X direction. 
     In addition, both the light amount distribution IDL 1  and the light amount distribution IDL 2  are constant within a predetermined range in the Y direction. 
     The X direction within the plane of the detected surface WA may be interpreted as a first direction. The Y direction within the plane of the detected surface WA may be interpreted as a second direction. 
     The reason for arranging the detection light division member  16  on the pupil plane TP is to divide the ±1st-order diffraction lights DP and DM into the first detection light DL 1  and the second detection light DL 2  in accordance with the incident direction to the detected surface WA regardless of the incident position to the detected surface WA. Accordingly, the position of the pupil surface TP at which the detection light division member  16  is arranged may not necessarily be a plane in which a plurality of rays incident from the same direction to different positions on the detected surface WA are collected at exactly one point. That is, the position may be a position that is shifted frontward or rearward to a certain degree along the optical axis AX 2  as long as the lights can be divided into the first detection light DL 1  and the second detection light DL 2  in accordance with the incident direction to the detected surface WA. This also applies to another pupil surface which will be described later. 
     The light reflected by the detected surface WA of the measured object W enters the incident surface  23   a  of the light reception prism  23  via the mirror  19 , the light reception-side first lens group  20 , the cylindrical lens  21 , and the light reception-side second lens group  22 . The optical axis AX 5  is an optical axis of the light reception-side first lens  20  and the light reception-side second lens  22 . The optical axis AX 4  is a reflected (mirrored) axis of the optical axis AX 5  by the mirror  19 . 
     The mirror  19 , the light reception-side first lens group  20 , and the light reception-side second lens group  22  are arranged at a symmetrical position and each has a symmetrical configuration to the mirror  18 , the light transmission-side first lens group  17 , and the light transmission-side second lens group  15 , respectively, with respect to a YZ plane that includes a center of the irradiation region IA. 
     The incident surface  23   a  of the light reception prism  23  is arranged at a symmetrical position to the diffraction grating  14   a  on the diffraction grating plate  14  with respect to the YZ plane that includes the center of the irradiation region IA. 
       FIG. 6  is a view of the incident surface  23   a  of the light reception prism  23  when seen from a normal direction with respect to the incident surface  23   a . An opening portion (slit) SL that is a light transmission portion having a longitudinal direction in the Y direction is formed at an intersection point of the optical axis AX 2  with the incident surface  23   a  or in the vicinity of the intersection point. A light-shielding portion OF that is covered by a light shield film is formed at a part other than the opening portion SL of the incident surface  23   a.    
     The incident surface  23   a  is optically conjugated with the detected surface WA of the measured object W via the mirror  19 , the light reception-side first lens group  20 , and the light reception-side second lens group  22 . That is, both the first detection light DL 1  and the second detection light DL 2  emitted from one point in the detected surface WA are focused to one point on the incident surface  23   a . An x2 axis that is an in-plane direction of the incident surface  23   a  is in an imaging relationship with the X-axis in the detected surface WA. That is, an arbitrary region along the X direction in the detected surface WA is imaged in a region along the x2 direction in the incident surface  23   a . The z2 axis is an axis in a direction perpendicular to the Y axis and the x2 axis. 
     The opening portion SL selectively transmits only light of the first detection light DL 1  and the second detection light DL 2  that is reflected by a portion having an imaging relationship with the opening portion SL in the irradiation region IA on the detected surface WA formed on the incident surface  23   a . Accordingly, the portion of the irradiation region IA on the detected surface WA having an imaging relationship with the opening portion SL on the incident surface  23   a  via the light reception-side first lens  20 , the light reception-side second lens  22 , and the like may be interpreted as the detection region DA as shown in  FIG. 5 ( a )  and  FIG. 5 ( b ) . That is, only the light reflected by the detection region DA on the detected surface WA of the first detection light DL 1  and the second detection light DL 2  transmits the opening portion SL. 
     The width in the x2 direction of the opening portion SL is a width Swx, the width in the Y direction is a width Swy, the width in the X direction of the detection region DA on the detected surface WA is a width Dwx, and the width in the Y direction is a width Dwy as shown in  FIG. 5 ( a ) . An imaging magnification ratio from the detected surface WA to the incident surface  23   a  by the light reception-side first lens  20  and the light reception-side second lens  22  is matched with a ratio of the width Swx to the width Dwx and a ratio of the width Swy to the width Dwy. 
     In order to focus the reflection light from the large detection region DA having the width Dwx on the narrow opening portion SL having the width Swx, the cylindrical lens  21  may be provided on a pupil surface RP 1  of the optical system constituted of the light reception-side first lens group  20  and the light reception-side second lens group  22  or in the vicinity of the pupil surface RP 1 . Here, the pupil surface RP 1  is a plane on which a plurality of rays that are emitted from different positions on the detected surface WA in the same direction are concentrated at approximately one point. 
     The light reception-side first lens group  20  and the light reception-side second lens group  22  may be interpreted as a first light reception optical system. 
     The x2 direction in the incident surface  23   a  may be interpreted as a third direction. The Y direction in the incident surface  23   a  may be interpreted as a fourth direction. 
     A pupil surface RP 1  may be interpreted as a first pupil surface. 
     The first detection light DL 1  and the second detection light DL 2  that have transmitted through the opening portion SL are deflected by a predetermined angle by a refraction action of the light reception prism  23 , are then emitted from the light reception prism  23 , and enter the front-side lens group  24  of the relay optical system ( 24 ,  26 ). The optical axis AX 6  is an optical axis of the front-side lens group  24  and the rear-side lens group  26  of the relay optical system. 
     Since the first detection light DL 1  and the second detection light DL 2  are diffracted when transmitting through the opening portion SL having a relatively narrow width Swx in the X2 direction, and the proceeding direction extends in the Z direction, it becomes impossible to distinguish between the +1st-order diffraction light DP and the −1st-order diffraction light DM. Accordingly, in  FIG. 2 , the light after transmitting through the opening portion SL is shown as the first detection light DL 1 . Further, in  FIG. 2  seen from the −Y direction, the second detection light DL 2  is displayed to overlap the first detection light DL 1  and is therefore not shown. 
     A compound separation member  25  is arranged on a pupil surface RP 2  by the front-side lens group  24  with respect to the incident surface  23   a . Here, the pupil surface RP 2  is a plane on which a plurality of rays that are emitted from different positions on the incident surface  23   a  in the same direction are concentrated at approximately one point. The details of the compound separation member  25  will be described later. 
     The first detection light DL 1  and the second detection light DL 2  that are emitted from the compound separation member  25  enter the polarization separation prism  27  via the rear-side lens group  26  of the relay optical system. A P-polarization component of the first detection light DL 1  and the second detection light DL 2  proceeds straight through the polarization separation prism  27  and forms an image of the P-polarization component of the opening portion SL on the light reception surface  29   a  on the light detection portion  28   a . On the other hand, an S-polarization component of the first detection light DL 1  and the second detection light DL 2  is reflected by the polarization separation prism  27  and forms an image of the S-polarization component of the opening portion SL on the light reception surface  29   b  on the light detection portion  28   b.    
     The opening portion SL is formed on the incident surface  23   a  of the light reception prism  23  that is greatly inclined from a plane perpendicular to the optical axis AX 6 . However, as shown in  FIG. 2 , an optical path length inside the light reception prism  23  is changed with respect to the Z direction, and thereby, the inclination of the image surface is corrected. As a result, the image of the opening portion SL is formed to coincide with the light reception surface  29   a  arranged perpendicular to the optical axis AX 6 . That is, the light reception prism  23  may be interpreted as an image surface inclination correction member. 
     A rotation direction about the optical axis AX 6  of the polarization separation prism  27  is set such that the P polarization and the S polarization with respect to the polarization separation surface  27   a  of the polarization separation prism  27  are matched with the P polarization and the S polarization with respect to the detected surface WA. 
     A photoelectric conversion signal of the detection light that is received by the light reception surfaces  29   a  and  29   b  of the light detection portions  28   a  and  28   b  and is photoelectrically converted is output from the light detection portions  28   a  and  28   b  and is input to a calculation unit PU. The calculation unit PU may be a computer device that includes a CPU and a memory. 
     The details of an image of the opening portion SL formed on the light detection portions  28   a  and  28   b  and the light reception surfaces  29   a  and  29   b  thereof will be described later. 
       FIG. 7  is a view showing an example of the compound separation member  25 . In  FIG. 7 , for ease of understanding, the optical axis AX 6  is represented to be parallel to the X-axis in the same manner as shown in  FIG. 2  and  FIG. 3 .  FIG. 7 ( a )  shows a cross-sectional view in an XY plane passing through the optical axis AX 6  of the compound separation member  25 , and  FIG. 7 ( b )  shows a cross-sectional view in an XZ plane passing through the optical axis AX 6  of the compound separation member  25 . 
     The compound separation member  25  is functionally divided along the optical axis AX 6  into a light separation member  25   a  on the incident side and a spectroscopic member  25   b  on the emission side. 
     A first block  251  arranged on the +Y side of the optical axis AX 6  and a second block  252  arranged on the −Y side of the optical axis AX 6  are arranged on an incident side of the light separation member  25   a . Incident surfaces of the first block  251  and the second block  252  are surfaces that are each rotated in different directions about a rotation axis parallel to the Z-axis with respect to a surface perpendicular to the optical axis AX 6 . Emission surfaces of the first block  251  and the second block  252  are similar to the incident surfaces of the first block  251  and the second block  252 . The shape of an incident surface of a third block  253  is matched with the shape of the emission surfaces of the first block  251  and the second block  252 . The emission surface of the third block  253  is a plane perpendicular to the optical axis AX 6 . 
     As a result, the light separation member  25   a  refracts (deflects) light that enters a further +Y side than the optical axis AX 6  and light that enters a further −Y side than the optical axis AX in different directions. It is preferable that the first block  251  and the second block  252  be formed of a material having a refractive index different from that of a material forming the third block  253 . 
     Since the compound separation member  25  is arranged on the pupil surface RP 2 , as shown in  FIG. 3 , the light that enters the further +Y side than the optical axis AX 6  is the first detection light DL 1 , and the light that enters the further −Y side than the optical axis AX 6  is the second detection light DL 2 . Then, the lights that are deflected from each other by a minute angle in the Y direction on the pupil surface RP 2  are formed at positions that are shifted from each other in the Y direction on the light reception surfaces  29   a  and  29   b.    
     The spectroscopic member  25   b  on the emission side is a prism in which a fourth block  254  and a fifth block  255  that are two triangular prisms are arranged such that oblique sides thereof face each other. An incident surface of the fourth block  254  is matched with the emission surface of the third block  253 , and an emission surface of the fifth block  255  is matched with a plane perpendicular to the optical axis AX 6 . An interface plane between the fourth block  254  and the fifth block  255  is a plane that includes a Y-axis direction. The fourth block  254  and the fifth block  255  are formed of a material having a different dispersion. 
     Therefore, at the interface plane between the fourth block  254  and the fifth block  255 , the lights having different wavelengths from each other included in the first detection light DL 1  and the second detection light DL 2  are each refracted at different angles depending on the wavelength. As a result, the first detection light DL 1  and the second detection light DL 2  are dispersed by the spectroscopic member  25   b , become detection lights DL 1   a  to DL 1   c  that are deflected by a minute angle in the Z direction from one another for each wavelength, and are emitted from the spectroscopic member  25   b.    
     The spectroscopic member  25   b  may be formed of one prism having a different refractive power depending on the wavelength. 
     Since the compound separation member  25  is arranged on the pupil surface RP 2 , the lights that are deflected by a minute angle in the Z-direction from each other by the compound separation member  25  are formed on the light reception surfaces  29   a  and  29   b  at positions that are shifted in the Z-direction from each other. 
     In  FIG. 7 , for ease of understanding, the second detection light DL 2  and detection lights DL 2   a  to DL 2   c  obtained by dispersing the second detection light DL 2  are not shown. 
       FIG. 8  is a view showing an image of a P-polarization component of the opening portion SL formed on the light reception surface  29   a . In  FIG. 8 , an x3 axis in an in-plane direction of the light reception surface  29   a  is in an imaging relationship with the x2 axis in the incident surface  23   a  described above. That is, an arbitrary region along the x2 direction of the incident surface  23   a  is imaged in a region along the x3 direction in the light reception surface  29   a.    
     As described above, the x2 axis which is the in-plane direction of the incident surface  23   a  is in an imaging relationship with the X axis in the detected surface WA. Accordingly, the x3 axis in the in-plane direction of the light reception surface  29   a  is also in an imaging relationship with the X axis in the detected surface WA. The z3 axis is an axis in a direction perpendicular to the Y axis and the x3 axis. 
     It should be noted that  FIG. 2  in which the optical path is shown to be linearly deployed is described such that the x3 axis in the in-plane direction of the light reception surface  29   a  is matched with the Z axis conveniently. 
     The relay optical system constituted of the front-side lens group  24  and the rear-side lens group  26  may be interpreted as a second light reception optical system. 
     The x2 direction in the incident surface  23   a  may be interpreted as a third direction. The Y direction in the incident surface  23   a  may be interpreted as a fourth direction. 
     The pupil surface RP 2  may be interpreted as a second pupil surface. 
     The x3 direction in the light reception surface  29   a  may be interpreted as a fifth direction. The Y direction in the light reception surface  29   a  may be interpreted as a sixth direction. 
     Since according to the separation and the deflection of the detection light by the compound separation member  25 , different wavelength components of each of the first detection light DL 1  and the second detection light DL 2  are guided to different positions on the light reception surface  29   a , a plurality of images (IM 1   a  to IM 1   c  and IM 2   a  to IM 2   c ) of the opening portion SL are formed on the light reception surface  29   a.    
     The images IM 1   a  to IM 1   c  and the images IM 2   a  to IM 2   c  that are formed to be away from each other in the Y direction on the light reception surface  29   a  are images formed by the first detection light DL 1  and the second detection light DL 2  deflected by a minute angle in the Y direction from each other by the light separation member  25   a  of the compound separation member  25 , respectively. The first detection light DL 1  and the second detection light DL 2  are dispersed by the spectroscopic member  25   b  into detection lights DL 1   a  to DL 1   c  and detection lights DL 2   a  to DL 2   c , respectively, that are deflected by a minute angle in a direction perpendicular to the Y direction from each other for each wavelength. Accordingly, images of the opening portion SL that are formed on the light reception surface  29   a  are also formed at different positions in the x3 direction depending on the wavelength. 
     The image IM 1   a  is an image by light having a first wavelength of the first detection light DL 1 , the image IM 1   b  is an image by light having a second wavelength of the first detection light DL 1 , and the image IM 1   c  is an image by light having a third wavelength of the first detection light DL 1 . 
     On the other hand, the image IM 2   a  is an image by light having a first wavelength of the second detection light DL 2 , the image IM 2   b  is an image by light having a second wavelength of the second detection light DL 2 , and the image IM 2   c  is an image by light having a third wavelength of the second detection light DL 2 . 
     In  FIG. 8 , for ease of understanding, the first detection light DL 1  and the second detection light DL 2  include lights of three different wavelengths. Accordingly, the number of images IM 1   a  to IM 1   c  by the first detection light DL 1  is three, and the number of images IMIM 2   a  to IM 2   c  by the second detection light DL 2  is three. 
     However, the wavelengths of lights included in the first detection light DL 1  and the second detection light DL 2  are not limited to three discrete wavelengths and may be four or more discrete different wavelengths. In this case, the number of images IMla to IM 1   c  by the first detection light DL 1  and the number of images IMIM 2   a  to IM 2   c  by the second detection light DL 2  are equal to or more than four. 
     Further, the wavelengths of lights included in the first detection light DL 1  and the second detection light DL 2  are not limited to a plurality of discrete wavelengths and may be a plurality of discrete or continuous wavelength bands. 
     The light reception surface  29   a  photoelectrically converts and outputs each of light amounts of these images IM 1   a  to IM 1   c  and IM 1 M 2   a  to IM 2   c . As an example, a plurality of separate photoelectric conversion units are provided on the light reception surface  29   a , the photoelectric conversion units each including each of the images IM 1   a  to IM 1   c  and IMIM 2   a  to IM 2   c . Each photoelectric conversion unit receives each of the images IM 1   a  to IM 1   c  and IMIM 2   a  to IM 2   c  and photoelectrically converts and outputs the light amount. 
     As the light detection portion  28   a , a two-dimensional image sensor in which microscopic light reception pixels are two-dimensionally aligned on the light reception surface  29   a  may be used. In this case, for example, one image IM 1   a  is received by a plurality of light reception pixels. In this case, the light detection portion  28   a  outputs a signal obtained by photoelectric conversion of each light amount of the detection light received by the plurality of light reception pixels as a photoelectric conversion signal. 
     When the two-dimensional image sensor is used as the light detection portion  28   a , since the resolution in the x3 direction of the light reception surface  29   a  is improved, the first detection light DL 1  and the second detection light DL 2  can be dispersed with higher accuracy and received. Thereby, light having a continuous spectrum can be used as the first detection light DL 1  and the second detection light DL 2 . 
     By narrowing the width in the x3 direction of each of the plurality of images IM 1   a  to IM 1   c  and IMIM 2   a  to IM 2   c  on the light reception surfaces  29   a  and  29   b  compared to the width in the Y direction, the first detection light DL 1  and the second detection light DL 2  can be dispersed with further high accuracy and received. 
     Since the light detection portion  28   b  has a configuration similar to that of the light detection portion  28   a  described above, the description thereof is omitted. 
     Further, since the image of the S polarization component of the opening portion SL formed on the light reception surface  29   b  is similar to the image of the P polarization component of the opening portion SL formed on the light reception surface  29   a  described above, the description thereof is omitted. 
     Hereinafter, a measurement principle in the surface position detection device  100  of the first embodiment is described. As described above, the light amount distribution IDL 1  and the light amount distribution IDL 2  shown in  FIG. 5 ( b )  are formed on the detected surface WA by the irradiation of the first detection light DL 1  and the second detection light DL 2 , respectively. Both of the first detection light DL 1  and the second detection light DL 2  are incident from a direction inclined by an incident angle θ in the −X direction relative to the normal line NV of the detected surface WA. Accordingly, when the detected surface WA moves upward or downward in the Z direction of  FIG. 1 , the light amount distribution IDL 1  and the light amount distribution IDL 2  are shifted in the X direction as a whole while maintaining the distribution shape of the light amount distribution IDL 1  and the light amount distribution IDL 2 . When the detected surface WA moves in the +Z direction, the light amount distribution IDL 1  and the light amount distribution IDL 2  are shifted in the −X direction. 
     On the other hand, the detection region DA shown in  FIG. 5 ( b )  is a region indicating that the first detection light DL 1  and the second detection light DL 2  reflected by the detection region DA transmit through the opening portion SL on the incident surface  23   a  of the light reception prism  23 . That is, the detection region DA is in an imaging relationship with the opening portion SL via the light reception-side first lens  20 , the light reception-side second lens  22 , and the like. However, since the optical axis AX 5  of the light reception-side first lens  20  is inclined in the +X direction relative to the normal line NV of the detected surface WA, when the detected surface WA moves upward or downward in the Z direction of  FIG. 1 , the position of the detection region DA is also shifted in the X direction on the detected surface WA. When the detected surface WA moves in the +Z direction, the detection region DA is shifted in the +X direction. That is, in accordance with the movement of the detected surface WA in the Z direction, the positional relationship in the X direction between the light amount distribution IDL 1  and the light amount distribution IDL 2  shown in  FIG. 5 ( b )  and the detection region DA is changed. 
     The light amount of each image IMla to IM 1   c  of the opening portion SL by the first detection light DL 1  on the light reception surface  29   a  is proportional to the sum of the light amount of the first detection light DL 1  in the detection region DA. Further, the light amount of each image IM 2   a  to IM 2   c  of the opening portion SL by the second detection light DL 2  on the light reception surface  29   a  is proportional to the sum of the light amount of the second detection light DL 2  in the detection region DA. Accordingly, the light amount of each image IMla to IM 1   c  and IM 2   a  to IM 2   c  is varied in accordance with the variation of position in the Z direction of the detected surface WA. 
     It should be noted that, unlike most conventional surface position detection devices, even when the position in the Z direction of the detected surface WA is varied, the position of each image IM 1   a  to IM 1   c  and IM 2   a  to IM 2   c  on the light reception surface  29   a  is not varied. 
       FIG. 9  is a view showing, as an example, a relationship between a position (horizontal axis) in a Z-axis direction of the detected surface WA, and a photoelectric conversion signal S 1   b  of the image IM 1   b  by a second wavelength component of the first detection light DL 1  and a photoelectric conversion signal S 2   b  of the image IM 2   b  by a second wavelength component of the second detection light DL 2 . As described above, the first detection light DL 1  and the second detection light DL 2  have the light amount distributions IDL 1  and IDL 2 , respectively, of sinusoidal functions having an equal period FX and an equal amplitude and having a displaced phase by half of the period FX on the detected surface WA. Therefore, both of the photoelectric conversion signal S 1   b  and the photoelectric conversion signal S 2   b  become signals represented by the following Expression (1) and Expression (2), respectively, in which, with respect to the position in the Z-axis direction of the detected surface WA, the periods FZ are equal to each other, the amplitudes A 1  are equal to each other, and the phases are displaced by half of the period FZ from each other. 
         S 1 b=A 1+ A 1×cos {2π( Z−Za )/ FZ}   (1)
 
         S 2 b=A 1− A 1×cos {2π( Z−Za )/ FZ}   (2)
 
     The Za is a Z position of the detected surface WA where the photoelectric conversion signal S 1   b  is maximized, and the photoelectric conversion signal S 2   b  is minimized. The Zb shown in  FIG. 9  is a Z position of detected surface WA which is located a position adjacent to the Za on the +Z side of the Za and at which the photoelectric conversion signal S 1   b  is minimized, and the photoelectric conversion signal S 2   b  is maximized. 
     The calculation unit PU calculates a Z position Zt of the detected surface WA which is located at an arbitrary position between the Za and the Zb by a calculation based on Expression (3) and Expression (4) from a value S 1   t  of the photoelectric conversion signal S 1   b  and a value S 2   t  of the photoelectric conversion signal S 2   b.    
         Zt=Za+FZ ×cos−1{( S 2 t−S 1 t )/(2× A 1)}/2π  (3)
 
         A 1=( S 2 t+S 1 t )/2  (4)
 
     The cos−1 is an inverse cosine function. 
     When the width Dwx in the X direction of the detection region DA is shorter than half of the period FX in the X direction of the light amount distribution IDL 1  and the light amount distribution IDL 2 , the variation of the photoelectric conversion signal S 1   b  and the photoelectric conversion signal S 2   b  can be increased when the detected surface WA is varied in the Z direction. As a result, it is possible to further improve the detection accuracy. 
     In the conventional surface position detection device, by obliquely radiating detection light on the detected surface, forming an irradiation region having a predetermined width in the X direction, and detecting a position of the center of gravity of the light amount in the X direction of the irradiation region, the Z position of the detected surface is detected. Accordingly, when there is a change in a reflectance in the X direction inside the irradiation region of the detected surface, since the position of the center of gravity of the light amount of the irradiation region is changed by the change in the reflectance, a detection error occurs. 
     For example, in a case of a semiconductor wafer in a formation process of an integrated circuit, the reflectance differs depending on a position of a surface of the wafer depending on an internal structure and the like. Accordingly, it is difficult to accurately detect a surface position of a semiconductor wafer surface in a conventional surface position detection device. 
     On the other hand, in the surface position detection device of the first embodiment, the detected Z position Zt of the detected surface WA is hardly affected by the change in the reflectance of the detection region DA. When the reflectance of the detection region DA is changed, both of the photoelectric conversion signal S 1   b  and the photoelectric conversion signal S 2   b  are increased and decreased with an equal proportionality coefficient in response to the change in the reflectance of the detection region DA. This is because even when (S 2   t −S 1   t ) in Expression (3) becomes α-fold due to the change in the reflectance of the detection region DA, since the A 1  in Expression (3), that is, (S 2   t +S 1   t )/2 in Expression (4) also becomes α-fold, the Zt obtained from Expression (3) is not changed. 
     That is, in the surface position detection device  100  of the first embodiment, a highly accurate surface position detection device that is not susceptible to variation of the reflectance of the detected surface WA can be realized. 
     In the above description, since the light amount distribution IDL 1  of the first detection light DL 1  radiated on the detected surface WA and the light amount distribution IDL 2  of the second detection light DL 2  are sinusoidal functions with respect to the X, the calculation unit PU calculates the detection position Zt on the basis of Expression (3) that includes the inverse cosine function. 
     However, in a case where the light amount distribution IDL 1  and the light amount distribution IDL 2  are other functions that are not the sinusoidal functions, the calculation unit PU may calculate the detection position Zt on the basis of an inverse function of the other function. Accordingly, the light amount distribution IDL 1  of the first detection light DL 1  radiated on the detected surface WA and the light amount distribution IDL 2  of the second detection light DL 2  are not limited to the sinusoidal function with respect to the X and may be another function. 
     However, at least in a portion corresponding to the detection region DA, the light amount distribution IDL 1  and the light amount distribution IDL 2  need to be smooth. This is because, when the light amount distribution IDL 1  and the light amount distribution IDL 2  are not smooth, that is, when the light amount distribution is changed not to be differentiable in the X direction at an arbitrary position, it becomes difficult to calculate the detection position Zt with high accuracy from the value S 1   t  of the photoelectric conversion signal S 1   b  and the value S 2   t  of the photoelectric conversion signal S 2   b . The smoothness may be defined as the function having a continuous differential coefficient (derivative function) within a certain interval (that is, is not bent). A definition that the light amount distribution IDL 1  and the light amount distribution IDL 2  are smooth in a portion corresponding to the detection region DA may be that, when the light amount distribution IDL 1  and the light amount distribution IDL 2  are fitted by a function, the fitted function has a continuous differential coefficient in the portion corresponding to the detection region DA. 
     When the light amount distribution IDL 1  and the light amount distribution IDL 2  are the sinusoidal functions as described above, since the calculation unit PU can calculate the detection position Zt using a common inverse cosine function or an inverse sine function, it is possible to simplify the configuration of the calculation unit PU. 
     The calculation unit PU may not calculate a surface position itself of the detected surface WA as described above and may calculate a conversion surface position in which the surface position of the detected surface WA is represented by an internal coordinate in the surface position detection device  100  or the like. Hereinafter, the surface position and the conversion surface position of the detected surface WA are also collectively or individually referred to as surface position information of the detected surface WA. 
     The calculation unit PU may calculate the amplitude A 1  from the sum of the value S 1   t  of the photoelectric conversion signal S 1   b  and the value S 2   t  of the photoelectric conversion signal S 2   b  on the basis of Expression (4). In this case, it is preferable that, before the measurement of the measured object W is performed, the amplitude A 1  (hereinafter, referred to as an amplitude A 0 ) with respect to a reference measurement object having a known reflectance of the detected surface WA be further calculated. Thereby, the calculation unit PU can calculate the reflectance of the detected surface WA of the measured object W from the ratio of the amplitude A 1  to the amplitude A 0 . 
     The above description is based on the photoelectric conversion signals S 1   b  and S 2   b  of the images IM 1   b  and IM 2   b  formed of the second wavelength components in the first detection light DL 1  and the second detection light DL 2 , respectively. However, of course, even when any one of pairs of images (a pair of the image IM 1   a  and the image IM 2   a , a pair of the image IM 1   b  and the image IM 2   b , and a pair of the image IM 1   c  and the image IM 2   c ) formed by the first detection light DL 1  and the second detection light DL 2  in each wavelength component is used, it is possible to perform the calculation of the position information of the detected surface WA according to the method described above. Further, the position information of the detected surface WA may be calculated by using each of the pairs of the images formed by the first detection light DL 1  and the second detection light DL 2  in each wavelength component. 
     In the case of the semiconductor wafer in the formation process of the integrated circuit described above or the like, the reflectance of the detected surface W may differ depending on the wavelength of the detection light depending on the internal structure and the like. Accordingly, the calculation unit PU may calculate position information of the detected surface WA from each of the pairs of images by a plurality of wavelength components in the first detection light DL 1  and the second detection light DL 2 , statistically process the plurality of calculated position information, and calculate final position information of the detected surface WA. The plurality of position information of the detected surface WA calculated from each of the pairs of images by the plurality of wavelength components may be interpreted as a position information element in order to be distinguished from the final position information of the detected surface WA. 
     Further, by performing the detection and the calculation similar to those described above of not only the image of the P polarization component received by the light detection portion  28   a  but also the image of the opening portion SL of the S polarization component received by the light detection portion  28   b , it is possible to calculate each of a plurality of position information elements of the detected surface WA. 
     The calculation unit PU may calculate an average value of the plurality of position information elements as the statistical process described above. In addition, the calculation unit PU may calculate, from a pair of images by a plurality of wavelength components, the reflectance of the detected surface WA of the measured object W at the wavelength for each P polarization component and S polarization component and calculate final position information on the basis of the polarization and the position information element and the reflectance for each wavelength. 
     The calculation unit PU may correct the calculated position information of the detected surface WA regarding the Z direction using information of a Z position of the stage ST measured by the interferometer or the encoder (not shown). 
     Further, the position information regarding the Z direction may be acquired throughout the entire surface of the detected surface WA by detecting the position in the Z direction of the detected surface WA while controlling and scanning the stage ST in the X direction and the Y direction by a control unit (not shown). 
     Modification Example 1 
     In the first embodiment described above, the surface position detection device  100  detects the position in the Z direction perpendicular to the detected surface WA of the measured object W. However, the position is not limited to a position in a direction perpendicular to the detected surface WA, and the position in a direction that intersects the detected surface WA may be detected. 
     Modification Example 2 
     In the first embodiment, the longitudinal direction of the opening portion SL on the incident surface  23   a  of the light reception prism  23  shown in  FIG. 6  is matched with the Y direction. However, the longitudinal direction of the opening portion SL is not necessarily matched with the Y direction, may be deviated by a predetermined angle from the Y direction within the plane of the incident surface  23   a , and may be the x2 direction in  FIG. 6 , that is, a direction that intersects the direction having an imaging relationship with the X direction on the detected surface WA. In this case, the longitudinal direction of the detection region DA on the detected surface WA and each image (IM 1   a  to IM 1   c , IM 2   a  to IM 2   c , and the like) of the opening portion SL formed on the light reception surfaces  29   a  and  29   b  is also deviated by a predetermined angle from the Y direction. In order to deal with this, the shape of each photoelectric conversion unit in the light reception surfaces  29   a  and  29   b  may be a shape that includes each image (IM 1   a  to IM 1   c , IM 2   a  to IM 2   c , and the like), and the longitudinal direction of the above-described pattern having a rectangular shape that constitutes the diffraction grating  14   a  may be deviated by a predetermined angle from the Y direction. 
     In the surface position detection device  100  of the first embodiment, both the light amount distribution IDL 1  of the first detection light DL 1  on the detected surface WA and the light amount distribution IDL 2  of the second detection light DL 2  are constant within a predetermined range in the Y direction. However, in a case where the longitudinal direction of the detection region DA is deviated by a predetermined angle from the Y direction as described above, it is preferable that both the light amount distribution IDL 1  and the light amount distribution IDL 2  be constant within a predetermined range in a direction that is deviated by a predetermined angle from the Y direction. 
     As understood from the above detection principle, the light amount distribution IDL 1  and the light amount distribution IDL 2  do not always need to be constant in the Y direction or a direction that is rotated by a predetermined angle from the Y direction. That is, the sum of the light amount distributions of the width Dwy in the Y direction of the detection region DA or the direction that is rotated by a predetermined angle from the Y direction may be constant at each position in the X direction. 
     However, both the light amount distribution IDL 1  and the light amount distribution IDL 2  are caused to be constant within a predetermined range in the Y direction or the direction that is rotated by a predetermined angle from the Y direction, and thereby, the impact of the variation of the reflectance is small even in a case where the reflectance of the detected surface WA is greatly varied in the Y direction. As a result, it is possible to perform detection of the surface position with further high accuracy. 
     Modification Example 3 
     The first detection light DL 1  and the second detection light DL 2  do not always need to enter the detected surface WA at the same incident angle θ. For example, the incident angles of the first detection light DL 1  and the second detection light DL 2  may be different from each other to a certain degree. In this case, by adding an optical member such as a prism that adjusts the difference between the incident angles of the +1st-order diffraction light DP and the −1st-order diffraction light DM included in each of the first detection light and the second detection light, it is possible to match the frequencies FX in the X direction of the light amount distributions of the first detection light DL 1  and the second detection light DL 2  on the detected surface WA with each other. 
     However, by equalizing the incident angles of the first detection light DL 1  and the second detection light DL 2 , it is not necessary to add such an optical member, and there is an advantage in that it is possible to simplify the optical system. 
     Modification Example 4 
     The sum of the light amounts of the first detection light DL 1  and the second detection light DL 2  in the irradiation region IA of the detected surface WA may not necessarily be constant along the X direction. As described above, the first detection light DL 1  and the second detection light DL 2  are received at different positions of the light reception surfaces  29   a  and  29   b  of the light detection portion  28   a  and  28   b . Therefore, in the light detection portions  28   a  and  28   b , the sensitivity of the photoelectric conversion with respect to the first detection light DL 1  and the second detection light DL 2  may be separately set easily. 
     Accordingly, this is because it is possible to obtain the photoelectric conversion signals S 1   a  and S 1   b  having the same amplitude by adjusting the sensitivity of the photoelectric conversion of the light detection portions  28   a  and  28   b , for example, even when the light amount distribution IDL 1  by the first detection light DL 1  and the light amount distribution IDL 2  by the second detection light DL 2  are different from each other. 
     However, by causing the sum of the light amounts of the first detection light DL 1  and the second detection light DL 2  in the irradiation region IA of the detected surface WA to be constant, it is possible to omit the sensitivity adjustment by the light detection portions  28   a  and  28   b  or the calculation unit PU, and it is possible to simplify the configuration of the surface position detection device  100 . 
     Modification Example 5 
     In the surface position detection device  100  of the first embodiment, the light-shielding portion OF and the opening portion SL are formed on the incident surface  23   a  of the light reception prism  23 , and the opening portion SL defines the detection region DA on the detected surface WA. However, since the detected surface WA, the opening portion SL, and the light reception surfaces  29   a  and  29   b  are in an imaging relationship (conjugate), a light reception region (a region where the photoelectric conversion is performed) in the light reception surfaces  29   a  and  29   b  may be limited instead of providing the light-shielding portion OF. That is, the width in the x3 direction of each light reception region may be set to be narrower than the width in the Y direction. Alternatively, in a case where the two-dimensional image sensor is used as the light detection portion  28   a , the calculation unit PU may perform the calculation of the surface position of the detected surface WA by using only the photoelectric conversion signal from a light reception pixel that corresponds to the opening portion SL instead of providing the light-shielding portion OF. That is, the calculation unit PU may calculate the surface position of the detected surface WA by using the photoelectric conversion signal from the light reception pixel within a range where the width in the x3 direction is narrower than the width in the Y direction of the two-dimensional image sensor. At this time, the compound separation member  25  may be omitted. Alternatively, the detection light from the light source  10  may be monochromatic light. 
     Modification Example 6 
     In the surface position detection device  100  of the first embodiment, the detection light division member  16  is arranged at the light transmission unit; however, the member that divides the first detection light DL 1  and the second detection light DL 2  is not limited to the detection light division member  16  arranged on the pupil plane TP of the light transmission unit. 
     For example, the optical system may be constituted such that the first detection light DL 1  and the second detection light DL 2  are formed to be superimposed on the detected surface WA without using the detection light division member  16 . 
     Further, the detection light division member  16  is not limited to the member constituted of a plurality of prisms described above. For example, a division mirror constituted of a plurality of reflection surfaces that are not parallel to one another may be used. 
     (Surface Position Detection Device of Second Embodiment) 
     Next, a surface position detection device  100   a  of a second embodiment is described. However, since most parts of the surface position detection device  100   a  of the second embodiment are common to the surface position detection device  100  of the first embodiment described above, only the differences are described below, and the common points are not described. 
     In the surface position detection device  100   a  of the second embodiment, a detection light division member  161  shown in  FIG. 10 ( a )  is used instead of the detection light division member  16  in the first embodiment shown in  FIG. 4 ( a ) . 
       FIG. 10 ( a )  is a perspective view showing the detection light division member  161 , and  FIG. 10 ( b )  is a view of the detection light division member  161  when seen from the light transmission-side first lens  17  side. The optical axis AX 2  and the Y axis of  FIG. 10  are the same as the optical axis AX 2  and the Y axis of  FIG. 4 , respectively. The detection light division member  161  includes: a prism  16   e  having a thickness in the optical axis AX 2  direction that is changed depending on the position of z1; and three prisms  16   f  to  16   h  arranged in contact with each other in the Y direction at a position away from the prism  16   e  to the downstream side of the optical path in the optical axis AX 2  direction. 
     The three prisms  16   f  to  16   h  are arranged in contact with each other in the Y direction, the boundaries between the prisms are parallel to the z1 direction, and the thicknesses in the optical axis AX 2  direction of the prisms are different from one another depending on the position of z1. 
     As a result, the detection light division member  161  divides, at the pupil surface TP, the detection light into three detection lights which are first detection light DL 10 , second detection light DL 20 , and third detection light DL 30  in the Y direction. Then, the detection light division member  161  deflects the proceeding direction of the first detection light DL 10 , the second detection light DL 20 , and the third detection light DL 30  by a minute angle in the z1 direction. 
       FIG. 11 ( a )  is a view representing light amount distributions IDL 10 , IDL 20 , and IDL 30  of the first detection light DL 10 , the second detection light DL 20 , and the third detection light DL 30 , respectively, on the detected surface WA in the surface position detection device  100   a  of the second embodiment. 
     By appropriately setting the deflection amount of the first detection light DL 10 , the second detection light DL 20 , and the third detection light DL 30  by the detection light division member  161 , the light amount distributions IDL 10 , IDL 20 , and IDL 30 , respectively, are light amount distributions that are displaced by one third of the period FX 2  of the intensity modulation thereof from each other. 
     The detection light division member  161  divides the detection light into the three detection lights which are the first detection light DL 10 , the second detection light DL 20 , and the third detection light DL 30  in the Y direction at the pupil surface TP of the light transmission unit. Accordingly, in the surface position detection device  100   a  of the second embodiment, even in the light separation member  25   a  of the compound separation member  25  arranged on the pupil surface RP 2  of a light reception unit, the detection light is divided into three in the Y direction of the pupil surface RP 2 . Specifically, a new block in which both of an incident surface and an emission surface are perpendicular to the optical axis AX 6  may be added between the first block  251  and the second block  252  of the light separation member  25   a  shown in  FIG. 7 ( b ) . Then, the shape of the surface on an incident side surface of the third block  253  may be matched with the shape of the surface on an emission side surface of the first block  251 , the second block  252 , and the new block. 
     As a result, images by the first detection light DL 10 , the second detection light DL 20 , and the third detection light DL 30  of the opening portion SL are formed separately from one another in the Y direction on the light reception surfaces  29   a  and  29   b.    
     As an example,  FIG. 11 ( b )  is a view showing a relationship between a position (horizontal axis) in the Z-axis direction of the detected surface WA and a photoelectric conversion signal S 10   b  of an image IM 10   b  by a second wavelength component of the first detection light DL 10 , a photoelectric conversion signal S 20   b  of an image IM 20   b  by a second wavelength component of the second detection light DL 20 , and a photoelectric conversion signal S 30   b  of an image IM 30   b  by a second wavelength component of the third detection light DL 30 . 
     The photoelectric conversion signal S 10   b , the photoelectric conversion signal S 20   b , and the photoelectric conversion signal S 30   b  are signals having the same period FZ and the same amplitude A 2  with respect to the position in the Z-axis direction of the detected surface WA and having a phase that is displaced by ⅓ of the period FZ represented by the following Expression (5) to Expression (7). 
         S 10 b=A 2+ A 2×cos {2π( Z−Zc )/ FZ 2}  (5)
 
         S 20 b=A 2+ A 2×cos {2π( Z−Zc )/ FZ 2−2π/3}  (6)
 
         S 30 b=A 2+ A 2×cos {2π( Z−Zc )/ FZ 2−4π/3}  (7)
 
     The Zc is a Z position of the detected surface WA where the photoelectric conversion signal S 10   b  is maximized. The Zd shown in  FIG. 11 ( b )  is a position that is away toward the +Z side of the Zc by the period FZ 2 . 
     The calculation unit PU calculates a candidate (Zu 1  to Zu 3 ) of a Z position Zu of the detected surface WA that is located at an arbitrary position between Za and Zb from a value S 10   u  of the photoelectric conversion signal S 10   b , a value S 20   u  of the photoelectric conversion signal S 20   b , and a value S 20   u  of the photoelectric conversion signal S 30   b  by a calculation based on Expression (8) to Expression (11). 
         Zu 1= FZ 2×[cos−1{( S 10 u−A 2)/ A 2}]/2π+ Zc   (8)
 
         Zu 2= FZ 2×[cos−1{( S 20 u−A 2)/ A 2}+2π/3]/2π+ Zc   (9)
 
         Zu 3= FZ 2×[cos−1{( S 20 u−A 2)/ A 2}+4π/3]/2π+ Zc   (10)
 
         A 2=( S 10 u+S 20 u+S 30 u )/3  (11)
 
     From the nature of the inverse cosine function, two values are obtained for each of the candidates Zu 1  to Zu 3  of the Z position Zu in a range from Zc to Zd. By employing values that are substantially matched with one another among the obtained values and performing an averaging process of Expression (12), the calculation unit PU calculates the Z position Zu of the detected surface WA. 
         Zu =( Zu 1+ Zu 2+ Zu 3)/3  (12)
 
     Even in the second embodiment, when the width Dwx in the X direction of the detection region DA is shorter than half of the period FX in the X direction of the light amount distribution IDL 10  to the light amount distribution IDL 30 , the variation of the photoelectric conversion signal S 10   b  to the photoelectric conversion signal S 30   b  can be increased when the detected surface WA is varied in the Z direction. As a result, it is possible to further improve the detection accuracy. 
     In the second embodiment, since the light amount distributions IDL 10 , IDL 20 , and IDL 30  having a different phase by one third of the period FX 2  of the intensity modulation are formed on the detected surface WA, the photoelectric conversion signals S 10   b  to S 30   b  are also changed as a so-called three-phase signal with respect to the Z position of the detected surface WA. Therefore, the position of the detected surface WA can be detected in a wider range (Zc to Zd) of Z compared to the first embodiment. 
     The above embodiment is described using the photoelectric conversion signals S 10   b , S 20   b , and S 30   b  of the second wavelength component in the first detection light DL 10  to the third detection light DL 0 ; however, the position of the detected surface WA can be calculated using the photoelectric conversion signal of each wavelength component of each detection light DL 10  to DL 30  in the same manner as in the first embodiment. 
     Further, by performing the detection and the calculation similar to those described above of not only the image of the P polarization component received by the light detection portion  28   a  but also the image of the opening portion SL of the S polarization component received by the light detection portion  28   b , it is possible to calculate each of a plurality of position information elements of the detected surface WA. The method of calculating final position information of the detected surface WA from the plurality of calculated position information elements is similar to the method in the first embodiment described above. 
     The configuration property described in each modification example of the first embodiment described above may also be applied to the surface position detection device of the second embodiment by adding appropriately required modifications. 
     Effects of First Embodiment, Second Embodiment, and Each Modification Example 
     (1) The surface position detection devices  100 ,  100   a  of the first embodiment, the second embodiment, and each modification example described above are the surface position detection device  100  that obtains position information of a detected surface WA along an axis (Z axis) that intersects the detected surface WA, the surface position detection device including: the light transmission unit TS by which a plurality of detection lights (DL 1 , DL 2 , and the like) having a smoothly modulated intensity in the detected surface WA in a first direction (X direction) within the detected surface WA are radiated and superimposed onto the detected surface WA obliquely from a direction having a direction component in the first direction and form an irradiation region IA on the detected surface WA; the light reception unit RS that has the light detection portions  28   a  and  28   b  having the light reception surfaces  29   a  and  29   b  arranged at an optically conjugated position with respect to the detected surface WA, receives at a different position of each of the light reception surfaces  29   a  and  29   b , the plurality of detection lights (DL 1 , DL 2 , and the like) reflected by the detection region DA of which the width DWx in the first direction is a predetermined value in the irradiation region IA, and outputs each photoelectric conversion signal of the plurality of detection lights (DL 1 , DL 2 , and the like); and the calculation unit PU that calculates position information of the detected surface WA based on the photoelectric conversion signal of the plurality of detection lights output from the light reception unit RS. 
     According to this configuration, a highly accurate surface position detection device  100  that is not susceptible to variation of the reflectance of the detected surface WA can be realized. 
     (2) By causing the light intensity in the second direction that intersects the first direction (X direction) in the irradiation region IA to be constant with respect to each of the plurality of detection lights (DL 1 , DL 2 , and the like), the impact of the variation of the reflectance is small even in a case where the reflectance of the detected surface WA is greatly varied in a direction that intersects the first direction. As a result, it is possible to perform detection of the surface position with higher accuracy. 
     (3) By causing the sum of the light amounts of the plurality of detection lights (DL 1 , DL 2 , and the like) in the detection region DA on the detected surface WA to be constant along the first direction (X direction), it is possible to easily calculate the reflectance of the detection region DA from the sum of photoelectric conversion signals (Sib, S 2   b , and the like) of the plurality of detection lights that are received by the light detection portions  28   a  and  28   b  and are photoelectrically converted. Then, the calculated reflectance is reflected in the calculation of the surface position of the detection region DA, and thereby, it is possible to perform detection of the surface position with further higher accuracy. 
     (4) By causing each of the plurality of detection lights (DL 1 , DL 2 , and the like) to have a modulated intensity in the first direction (X direction) by the sinusoidal function having the same period FX and the same amplitude and have a different phase from each other in the first direction of the sinusoidal function in the detected surface WA, it is possible to simplify the configuration of the calculation unit PU. 
     (5) By causing the plurality of detection lights to be a configuration that includes the first detection light DL 10 , the second detection light DL 20 , and the third detection light DL 30  each having phases of the sinusoidal function different by one third of the period FX 2  from one another, it is possible to detect the position on the detected surface WA over a wider range in a measurement direction (Z direction). 
     (6) By causing the width Dwx in the first direction (X direction) of the detection region DA to be shorter than half of the period FX of the sinusoidal function, it is possible to increase the variation of the photoelectric conversion signals S 1   b  and S 2   b  and the like when the detected surface WA is varied in the Z direction. As a result, it is possible to further improve the detection accuracy. 
     (7) A configuration can be employed in which each of the plurality of detection lights (DL 1 , DL 2 , and the like) radiated on the detected surface WA by the light transmission unit TS has a different wavelength, and the light reception unit RS includes the spectroscopic member  25   b  that disperses each of the plurality of detection lights depending on the wavelength and guides the dispersed detection lights to different positions on the light reception surfaces  29   a  and  29   b . Further, a configuration can also be employed in which each of the light detection portions  28   a  and  28   b  outputs photoelectric conversion signals (S 1   b , S 2   b , and the like) for each of a plurality of different wavelengths that enters a different position with respect to each of the plurality of detection lights (DL 1 , DL 2 , and the like), and the calculation unit PU calculates position information of the detected surface WA on the basis of the photoelectric conversion signals (S 1   b , S 2   b , and the like) of the plurality of detection lights for each of the plurality of different wavelengths. In this case, since the position of the detected surface WA is detected by the detection light of a plurality of different wavelengths, the position of the detected surface WA can be detected with higher accuracy. 
     In the surface position detection device of the first and second embodiments, the position information of the detected surface WA may not be obtained. As an example, in the surface position detection device of the first and second embodiments, a spectral reflectance distribution of the detected surface WA may be measured without obtaining the position information of the detected surface WA. 
     (Exposure Apparatus of Third Embodiment) 
       FIG. 12  is a view schematically showing an exposure apparatus  200  of a third embodiment. The exposure apparatus  200  of the third embodiment is an exposure apparatus for exposing and transferring an exposure pattern to a photoresist (resist) PR formed on a surface of a semiconductor wafer or a substrate (hereinafter, collectively referred to as a “substrate”) WF for a display device. The exposure apparatus  200  includes the surface position detection device  100 ,  100   a  of the first embodiment or the second embodiment described above. The surface position detection device  100 ,  100   a  treats the substrate WF as the measured object W described above and treats the surface of the photoresist formed on the surface of the substrate WF as the detected surface WA described above. 
     In the direction of XYZ axes of  FIG. 12 , a direction parallel to an optical axis AXP of a projection optical system  57  is a Z-axis direction. 
     The substrate WF carried in the exposure apparatus  200  is mounted on a movable substrate stage  59  on a platen  61  and is arranged below the surface position detection device  100  by the movement of the substrate stage  59 . A control device  70  causes the surface position detection device  100  to detect position information in the Z direction of a plurality of points of the surface of the substrate WF while sending a control signal S 5  and moving the substrate stage  59  in an XY plane. At this time, the position information in the Z direction of the substrate stage  59  on which the substrate WF is mounted is measured by interferometers  63   a  and  64   b  that are held integrally with the surface position detection device  100  via the positions of reference mirrors  60   a  and  60   b . The position in the XY-direction of the substrate stage  59  is measured by an interferometer  62  via the position of the reference mirror  60   b . The interferometers  63   a  and  64   b  may be interpreted as a first measurement unit. 
     Information about the Z-direction position of the surface of the substrate WF detected by the surface position detection device  100  and position information in the Z direction of the substrate stage  59  are transmitted as a signal S 2  to the control device  70 . Position information in the XY direction of the substrate stage  59  is transmitted as a signal S 3  to the control device  70 . Map data representing the position information in the Z direction with respect to the XY position of the surface of the substrate WF is generated in the control device  70  on the basis of the signal S 2  and the signal S 3 . 
     Subsequently, the control device  70  moves the substrate stage  59  in the XY plane such that the substrate WF is arranged below the projection optical system  57  and exposes the resist PR formed on the surface of the substrate WF. The exposure may be so-called step exposure or may be scan exposure. Upon exposure, the control device  70  controls the substrate stage  59  on the basis of the map data representing the position information in the Z direction with respect to the XY position of the surface of the substrate WF. That is, the control device  70  transmits a control signal S 4  to the substrate stage  59 , moves the substrate stage  59  in the XY direction, and drives the substrate stage  59  in the Z direction such that the surface of the substrate WF in an exposure field of the projection optical system  57  is matched with an image surface of the projection optical system  57 . If necessary, the control device  70  minutely rotates (levels) the substrate stage  59  such that the Y-axis direction and the X-axis direction are rotation centers. 
     The position in the Z direction of the substrate stage  59  during exposure is measured by interferometers  58   a  and  58   b  held integrally with the projection optical system  57  via positions of reference mirrors  60   a  and  60   b  and is transmitted as a signal S 1  to the control device  70 . The position in the XY direction of the substrate stage  59  during exposure is measured by an interferometer  62  via a position of the reference mirror  60   b  and is transmitted as a signal S 3  to the control device  70 . The interferometers  58   a  and  58   b  may be interpreted as a second measurement unit. 
     The control device  70  controls the substrate stage  59  during exposure on the basis of the map data representing the position information in the Z direction with respect to the XY position of the surface of the substrate WF described above, the signal S 1 , and the signal S 3 . 
     In the exposure operation described above, illumination light from an exposure light source  50  is illuminated via an illumination optical system  51  to an original plate (mask pattern) drawn on a mask  52 . As a result, an image of the original plate is projected via the projection optical system  57  to the resist PR on the substrate WF, and the resist PR is exposed with an exposure pattern. 
     In a case where the exposure operation is the scan exposure, the mask  52  and the substrate WF synchronize and scan relative to the projection optical system  57  during the exposure operation. For this scanning, the mask  52  is mounted on the mask stage  53 , and the mask stage  53  is moveable in the X direction on a mask platen  54 . The position of the mask stage  53  is measured by a mask interferometer  56  via a position of a mask reference mirror  55 . 
     In a case where the exposure operation is a step exposure, the substrate stage  59  is stationary during exposure of one shot, and the substrate stage  59  moves in the X direction or the Y direction by a predetermined distance between shots. 
     The projection optical system  57  may be a so-called immersion optical system in which a liquid is provided between the projection optical system  57  and the substrate WF. Alternatively, the exposure apparatus  200  is not limited to an apparatus that performs exposure by light or ultraviolet light and may be an apparatus that performs exposure by an electron beam or X-ray. 
     The interferometers  58   a ,  58   b ,  63   a ,  63   b , and  62  are not limited to interferometers and may be encoders for position measurement. 
     (Effects of Exposure Apparatus of Third Embodiment) 
     (8) The exposure apparatus  200  of the third embodiment includes the surface position detection device  100  of the first embodiment or the second embodiment as a device that detects the position in the Z direction of the surface of the substrate WF on which the resist PR is formed. According to this configuration, it is possible to reduce the measurement error caused by the reflectance distribution at the surface of the substrate WF and measure the surface position of the surface of the substrate WF with high accuracy. As a result, in the exposure apparatus of the third embodiment, it is possible to perform position alignment of the surface of the substrate WF on which the resist PR is formed with respect to the projection optical system  57  with high accuracy, and therefore, it is possible to perform good projection exposure. 
     (Substrate-Processing System of Fourth Embodiment) 
       FIG. 13  is a view schematically showing a substrate-processing line that includes a substrate-processing system  300  of a fourth embodiment. The substrate-processing system  300  includes: the surface position detection device  100 ,  100   a  of the first embodiment, the second embodiment, or each modification example described above; the exposure apparatus  200  of the second embodiment described above; and a data-holding device  110 . 
     In the substrate-processing system  300 , a substrate WF having a surface on which a resist PR is formed by a coater developer (track system)  104  is transported to the surface position detection device  100  by a transport mechanism  101 . The surface position detection device  100  includes, in the inside thereof, a stage ST on which the substrate WF is mounted, and the stage ST detects the position information of the surface of the substrate WF across a front surface of the substrate WF by moving the substrate WF in a direction within the surface. Further, the surface position detection device  100  may measure the reflectance of the surface of the substrate WF. Further, the surface position detection device  100  may measure a plurality of position information and reflectance of the surface of the substrate WF for each detection wavelength. The position information of the surface of the substrate WF measured by the surface position detection device  100  or even information of the reflectance is transmitted to the data-holding device  110  and is temporarily stored. 
     The substrate WF of which the surface position is detected by the surface position detection device  100  is transported to the exposure apparatus  200  by the transport mechanism  102 . The position information of the surface of the substrate WF or even the information of the reflectance stored in the data-holding device  110  is also transmitted to the exposure apparatus  200 . In the exposure apparatus  200 , the position of the surface of the substrate WF is detected using the position information of the surface of the substrate WF measured by the surface position detection device  100  or even the information of the reflectance. Then, the exposure apparatus  200  operates the substrate stage  59 , causes the surface of the substrate WF to be matched with an image surface of the projection optical system  57 , and exposes an exposure pattern onto a resist PR on the surface of the substrate WF. 
     In the substrate-processing system  300  of the fourth embodiment, the position information of the surface of the substrate WF or more accurate information of the reflectance has already been measured in the surface position detection device  100 . Accordingly, the surface position detection device  100  in the exposure apparatus  200  may be omitted, and alternatively, a conventional surface position detection device may be used. 
     The substrate WF exposed by the exposure apparatus  200  is transported to the coater developer  104  by a transport mechanism  103 , and the resist PR on the substrate WF is developed by the coater developer  104 . Then, the substrate WF is transported to a processing device  106  by a transport mechanism  105 . The surface of the substrate WF or a film formed on the surface of the substrate WF is processed (etched, ion implanted, or the like) by the processing device  106  using the developed resist PR as a mask, that is, on the basis of the resist pattern PR formed in the resist PR. Accordingly, the substrate-processing system  300  can form a circuit pattern on the basis of the exposure pattern exposed to the resist PR on the substrate WF and fabricate a device. 
     In the substrate-processing system  300  of the fourth embodiment described above, the data-holding device  110  that temporarily stores the position information of the surface of the substrate WF measured by the surface position detection device  100  or even the information of the reflectance is provided; however, the embodiment is not limited thereto. The data-holding device  110  may be embedded in the surface position detection device  100  or may be embedded in the exposure apparatus  200 . Alternatively, the data-holding device  110  may be included in a computer or a storage device that manages a device factory such as a semiconductor factory where the surface position detection device  100  and the exposure apparatus  200  are installed and that is connected to the surface position detection device  100  and the exposure apparatus  200  by a network. 
     (Effects of Substrate-Processing System of Fourth Embodiment) 
     (9) The substrate-processing system of the fourth embodiment is the substrate-processing system  300  in which the substrate WF is a processing target, the substrate-processing system including: a measurement device having a first stage ST on which the substrate WF is mounted and the surface position detection device  100 ,  100   a  of the first embodiment, the second embodiment, or the modification example described above that measures a position in a direction (Z direction) which intersects the surface of a plurality of points on the surface of the substrate WF; and the exposure apparatus  200  that includes a second stage  59  on which the substrate WF for which the measurement by the measurement device has been completed is mounted and that exposes the substrate WF which is mounted on the second stage  59 . The exposure apparatus  200  performs the exposure while changing a position in the direction which intersects the surface of the substrate WF using at least a measurement result by the measurement device  100 ,  100   a.    
     According to this configuration, it is possible to reduce the measurement error caused by the reflectance distribution at the surface of the substrate WF and perform position alignment of the surface of the substrate WF on which the resist PR is formed with respect to the projection optical system  57  with high accuracy. Thereby, it is possible to form a good exposure pattern on the substrate WF. 
     (Device-Manufacturing Method of Fifth Embodiment) 
     A device-manufacturing method of a fifth embodiment is described with reference to  FIG. 14 . The device-manufacturing method of the fifth embodiment is a method of manufacturing a device using the exposure apparatus  200  of the third embodiment described above or the substrate-processing system  300  of the fourth embodiment. Accordingly, the details of the operation of the exposure apparatus  200  of the third embodiment and the substrate-processing system  300  of the fourth embodiment are described above. 
     In step S 100 , a film formed of a dielectric, a metal, or a semiconductor is formed on a surface of a substrate WF (a semiconductor wafer or a substrate for a display device). Next, in step S 101 , a photoresist (resist) PR is formed on the film formed in step S 100 . Then, in step S 102 , the surface position detection device  100  included in the exposure apparatus  200  of the third embodiment described above or the substrate-processing system  300  of the fourth embodiment is used, and the position of the surface of the resist PR formed on the surface of the substrate WF is detected. 
     Next, in step S 103 , by the exposure apparatus  200 , an exposure pattern is exposed to the resist PR on the substrate WF using the position of the surface of the resist PR detected by the surface position detection device  100  in step S 102 . Then, in step S 104 , the resist PR on which the exposure pattern is exposed is developed, and a resist pattern is formed. Then, in step S 105 , processing such as etching, ion implantation or the like is performed on the film formed on the substrate WF or the surface of the substrate WF using the resist pattern as a mask. 
     According to step S 100  to step S 105  described above, a circuit pattern of one layer that constitutes a device is formed on the substrate WF. 
     Accordingly, after the completion of step S 105 , by proceeding to the next step and repeatedly performing step S 100  to step S 105  again, it is possible to manufacture a device (a semiconductor integrated circuit, a display device, and the like) constituted of a plurality of layers. 
     (Effects of Device-Manufacturing Method of Fifth Embodiment) 
     (10) From one point of view, the device-manufacturing method described above includes: forming the resist PR on the surface of the substrate WF; detecting the position of the surface of the resist PR formed on the surface of the substrate WF using the exposure apparatus  200  of the third embodiment described above, setting the surface of the resist PR at a predetermined position in the optical axis (AXP) direction of the projection optical system  57 , and exposing the exposure pattern; developing the resist PR; and processing the surface of the substrate WF on the basis of the resist pattern PR formed by the developing. 
     According to this configuration, it is possible to reduce the measurement error caused by the reflectance distribution at the surface of the substrate WF and perform position alignment of the surface of the substrate WF on which the resist PR is formed with respect to the projection optical system  57  with high accuracy. Thereby, it is possible to form a good exposure pattern on the substrate WF, and eventually, it is possible to manufacture a high-performance device. 
     (11) From another point of view, the device-manufacturing method described above includes: forming the resist PR on the surface of the substrate WF; and detecting a position in a direction which intersects the surface of a plurality of points in a surface of the resist PR formed on the surface of the substrate WF using the substrate-processing system  300  of the fourth embodiment. The method includes: exposing an exposure pattern while changing the position of the surface of the resist PR in the direction which intersects the surface based on the detected position of the plurality of points; and forming a circuit pattern based on the exposure pattern. 
     According to this configuration, it is possible to reduce the measurement error caused by the reflectance distribution at the surface of the substrate WF and perform position alignment of the surface of the substrate WF on which the resist PR is formed with respect to the projection optical system  57  with high accuracy. Thereby, it is possible to form a good exposure pattern on the substrate WF, and eventually, it is possible to manufacture a high-performance device. 
     The present invention is not limited to the embodiments described above. Other aspects conceivable within the scope of the technical ideas of the present invention are also included within the scope of the present invention. The present embodiments may combine all or part of the aspects described above. 
     DESCRIPTION OF THE REFERENCE SYMBOLS 
     
         
         
           
               100 ,  100   a  Surface position detection device 
               200  Exposure apparatus 
               300  Substrate-processing system 
             TS Light transmission unit 
             RS Light reception unit 
             PU Calculation unit 
             W Measured object 
             WA Detected surface 
               14  Diffraction grating plate 
               17  Light transmission-side first lens 
               15  Light transmission-side second lens 
               18 ,  19  Mirror 
             TP Pupil plane 
             RP 1  Pupil plane 
             RP 2  Pupil plane 
             AX 1  to AX 6  Optical axis 
               20  Light reception-side first lens 
               22  Light reception-side second lens 
               23  Light reception prism 
               24  Front-side lens group 
               26  Rear-side lens group 
               27  Polarization separation prism 
               28   a ,  28   b  Light detection portion 
               29   a ,  29   b  Light reception surface 
             ST Stage ST 
               12  Light introduction portion  12   
               13  Condenser lens 
               16  Detection light division member 
               25  Compound separation member 
               25   a  Light separation member  25   a    
               25   b  Spectroscopic member 
             IA Irradiation region 
             DA Detection region 
             DP+1st-order diffraction light 
             DM−1st-order diffraction light 
             DL 1 , DL 10  First detection light 
             DL 2 , DL 20  Second detection light 
             SL Opening portion 
             IM 1   a  to IM 1   c , IM 2   a  to IM 2   c  Image 
             S 1   a , S 1   b  Photoelectric conversion signal