Imaging device, exposure device, and article manufacturing method

Abstract

To provide a small-sized imaging device which can take a plurality of illumination systems.SOLUTION: An imaging device includes: an illumination part which includes an illumination region adjustment part capable of executing first adjustment of adjusting an illumination region of an object by illumination light so that much illumination light including light of a predetermined wavelength is incident on a first region out of the first region and a second region of the object, and second adjustment of adjusting the illumination region so that the much illumination light is incident on the second region out of the first region and the second region, and makes the illumination light incident on the object; an imaging part for receiving light from the object, and thereby acquiring an image of the object; and a stage having a mounting surface on which the object is mounted, and that reflects light of a predetermined wavelength.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an imaging apparatus, an exposure apparatus, and a method for manufacturing an article. [Background technology]

[0002] 2. Description of the Related Art Conventionally, imaging devices that employ an epi-illumination method are known in which illumination light is incident perpendicularly from the side of an object where an imaging optical system is provided, i.e., from the front side of the object, and specularly reflected light from the object is received by an imaging element. Such an imaging device employing an epi-illumination method is used to image a relatively wide variety of objects, and is particularly suitable for imaging objects with clear contours.

[0003] In addition, imaging devices have been known that employ an oblique incidence illumination (side illumination) method in which illumination light having an angle of incidence equal to or greater than the numerical aperture of the imaging optical system is obliquely incident on an object from the front side in a non-perpendicular and non-parallel direction, and the image sensor receives scattered light from the object. An imaging device that employs such an oblique incidence illumination method can obtain an image in which the contours of an object are emphasized.

[0004] Patent Document 1 discloses an imaging device that improves the contrast of edges, notches, characters, etc. in the acquired image by obliquely illuminating light from multiple directions that are non-perpendicular and non-parallel to the main surface of a substrate on which the edges, notches, characters, etc. are formed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-169211 A Summary of the Invention [Problem to be solved by the invention]

[0006] Also known imaging devices employ a back-side transmitted illumination method in which illumination light is incident on the side of the object opposite to the side on which the imaging optical system is provided, i.e., the back side of the object, and the transmitted light that passes through the object is received by an imaging element. In an imaging device that employs such a back-side illumination method, when an object has a transmissive portion and a light-shielding portion, a difference in brightness occurs between the two, making it possible to obtain a high-contrast image of such an object.

[0007] That is, depending on the structure and optical characteristics of an object, the illumination method that is effective for acquiring a high-contrast image of the object varies from among the epi-illumination method, the oblique incidence illumination method, and the back-transmitted illumination method. Therefore, an imaging device that employs multiple illumination methods and can select an appropriate illumination method depending on the structure and optical characteristics of an object can capture high-contrast images of various objects.

[0008] However, when multiple illumination methods are adopted in an imaging device, there is a risk that the device may become large, for example by providing light sources for emitting illumination light on both the same side and the opposite side of the imaging optical system in order to adopt both the oblique incidence illumination method and the back surface transmitted illumination method. SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a compact imaging device capable of employing a plurality of illumination methods. [Means for solving the problem]

[0009] The imaging device of the present invention includes an illumination area adjustment unit capable of performing a first adjustment to adjust the illumination area of ​​the object by illumination light so that more illumination light including light of a predetermined wavelength is incident on a first area out of a first area and a second area of ​​the object, and a second adjustment to adjust the illumination area so that more illumination light is incident on a second area out of the first area and the second area, and is characterized in that it is equipped with an illumination unit that incidents illumination light on the object, an imaging unit that obtains an image of the object by receiving light from the object, and a stage on which the object is placed and which has a mounting surface that reflects light of the predetermined wavelength. Effect of the Invention

[0010] According to the present invention, it is possible to provide a small-sized imaging device capable of adopting a plurality of illumination methods. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view of an exposure apparatus equipped with a position measurement apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a top view of an alignment mark formed on a plate. [Diagram 3] 1 is a cross-sectional view of a position measurement device according to a first embodiment. [Figure 4] 3A and 3B are diagrams showing examples of images formed on an imaging surface in the position measurement device according to the first embodiment. [Diagram 5] 1 is a cross-sectional view of a position measurement device according to a first embodiment. [Figure 6] FIG. 11 is a cross-sectional view of a position measurement device according to a second embodiment. [Figure 7] FIG. 11 is a cross-sectional view of a position measurement device according to a second embodiment. [Figure 8] FIG. 11 is a cross-sectional view of a position measurement device according to a third embodiment. [Figure 9] FIG. 11 is a cross-sectional view of a position measurement device according to a third embodiment. [Figure 10] FIG. 1 is a cross-sectional view of a conventional position measuring device. [Figure 11] 1A to 1C are diagrams showing examples of images formed on an imaging plane in each of conventional position measurement devices employing an epi-illumination system, an oblique incidence illumination system, and a back-side transmitted illumination system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an imaging device according to the present embodiment will be described in detail with reference to the accompanying drawings. Note that the drawings shown below are drawn at a different scale than the actual scale in order to facilitate understanding of the present embodiment. In the following, the direction parallel to the optical axis of the projection optical system 40 is defined as the Z direction, the scanning directions of the mask 20 and the plate 60 within a plane (the plate surface of the plate 60) perpendicular to the Z direction are defined as the Y direction, and the non-scanning direction perpendicular to the Y direction is defined as the X direction.

[0013] [First embodiment] 2. Description of the Related Art Lithography processes, which are included in the manufacturing processes for semiconductor devices, liquid crystal displays, etc., use exposure apparatuses that transfer a pattern formed on an original such as a reticle or mask via a projection optical system onto a substrate such as a wafer or glass plate coated with a photosensitive agent.

[0014] In the exposure apparatus, since it is required to perform highly accurate alignment between the original and the substrate in order to accurately transfer the pattern of the original onto the substrate, a position measurement device is provided to measure the positions of the original and the substrate in accordance with this requirement. Generally, when measuring the positions of an original and a substrate, the positions of the alignment marks drawn on the original and the substrate are measured by capturing images of the alignment marks using a dedicated imaging device (observation device, microscope).

[0015] Furthermore, on the master and substrate, alignment marks are generally drawn using materials such as metal or insulating film, and the optical properties, thickness, taper angle, etc. of the material vary depending on the conditions of the manufacturing process. Furthermore, the surface of the alignment mark thus drawn on the substrate is often coated with a photosensitive agent for exposure.

[0016] As the photosensitizer, various types having different optical properties are used depending on the manufacturing process of the semiconductor device, liquid crystal display, or the like. Therefore, imaging devices for measuring the positions of alignment marks formed on a substrate in particular are required to be able to handle the various optical characteristics of the applied photosensitive agent, in other words, to have high measurement robustness.

[0017] That is, in an imaging device for measuring the position of an alignment mark formed on a substrate, it is preferable that the imaging device be configured so that optical parameters can be changed to accommodate various optical characteristics of the photosensitive agent applied to the substrate. Such optical parameters include, for example, illumination methods such as epi-illumination, oblique incidence illumination (side illumination), and back-transmitted illumination.

[0018] In the epi-illumination method, illumination light is incident perpendicularly on an object from the side where an imaging optical system such as an objective lens is provided, i.e., the front side of the object, and the image sensor mainly receives specularly reflected light from the object. Such an epi-illumination method is used for imaging a relatively wide variety of objects, and is particularly suitable for imaging objects with clear contours.

[0019] In the oblique incidence illumination method, illumination light having an angle of incidence equal to or greater than the numerical aperture of the imaging optical system is made to be obliquely incident on an object from the front side of the object, and scattered light from the object is received by an imaging element. In such oblique incidence illumination schemes, a relatively bright light source is required to increase the intensity of the illumination light and thereby the intensity of the scattered light. On the other hand, since the contours of an object can be emphasized, this can be useful for objects whose contour contrast would be low under other illumination methods.

[0020] In the backside transmission illumination method, illumination light is incident on the object from the side opposite to the side where the imaging optical system is provided, i.e., from the back side of the object, and the transmitted light that passes through the object is received by the imaging element. In such a back-side transillumination method, when an object has a transmissive portion and a light-shielding portion, a difference in brightness occurs between the two, making it possible to image such an object with high contrast.

[0021] As described above, in an imaging apparatus, the effective illumination method varies among the epi-illumination method, the oblique incidence illumination method, and the back-side transmission illumination method depending on the structure and optical characteristics of the object. That is, in order to achieve high measurement robustness in an imaging apparatus, it is preferable to have a plurality of the above illumination methods.

[0022] However, in order to perform illumination using the back-transmitted illumination method, it is generally necessary to either embed a light source within the stage on which the object is placed, or to guide illumination light from an external light source to the back side of the stage on which the object is placed. In that case, the structure below the stage becomes complicated, which may result in an increase in size and cost. In addition, adding such a configuration to an imaging device that employs a reflecting illumination method or an oblique incidence illumination method in order to perform a back-side transmitted illumination method also leads to an increase in size and cost.

[0023] Furthermore, in an imaging device that employs a back-side transmitted illumination method, when illuminating light is emitted from a light source provided on the back side of an object, the area of ​​the support surface of the stage on which the object is placed, through which the illuminating light passes, must be formed as a transparent area. In other words, in a configuration in which the position of an alignment mark on a substrate in an exposure apparatus is measured using an imaging device that employs such a back-side transmitted illumination method, there is a risk that the exposure performance of the exposure apparatus will be degraded by forming a portion of the substrate mounting surface of the substrate stage into a transparent area.

[0024] For example, if the substrate is made of glass, after the exposure light passes through the substrate, reflected light or scattered light is generated on the substrate placement surface of the stage, and the photosensitive agent coated on the substrate is exposed to the reflected light or scattered light. In this case, if a portion of the substrate supporting surface of the substrate stage is formed as a transparent area, the intensity of the generated reflected light and scattered light will change depending on the position on the substrate surface, causing uneven exposure in the photosensitive agent applied to the substrate, thereby reducing the resolution performance during exposure.

[0025] Furthermore, in exposure apparatuses, the substrate stage is configured to be able to accelerate or stop suddenly in order to improve productivity, so the substrate is often held by suction on the substrate stage using vacuum suction or the like. In this case, if a partial area of ​​the substrate placement surface of the substrate stage is formed as a transparent area, the substrate adsorption function of the substrate stage is reduced.

[0026] Furthermore, in an exposure apparatus, the substrate mounting surface of the substrate stage is formed to have a high degree of flatness. Therefore, if a portion of the substrate mounting surface of the substrate stage is formed as a transmission area, it becomes difficult to maintain a high degree of flatness of the substrate mounting surface.

[0027] In view of the above, the present embodiment aims to provide an imaging device that is small and low-cost while adopting multiple illumination methods, and that can suppress a decrease in the exposure performance of an exposure device even when mounted on the exposure device.

[0028] FIG. 1 shows a schematic cross-sectional view of an exposure apparatus 1 equipped with a position measurement apparatus 50 as an imaging apparatus according to the first embodiment.

[0029] The exposure apparatus 1 includes an illumination optical system 10, a mask stage 30, a projection optical system 40, a position measuring apparatus 50 according to this embodiment, and a plate stage 70 (substrate stage). The illumination optical system 10 is configured to uniformly illuminate a mask 20 (original) on which a pattern is drawn by irradiating it with exposure light with a predetermined light quantity and angle distribution.

[0030] The mask stage 30 is configured to hold the mask 20 and to be driven in rotational directions about axes parallel to the X-, Y-, and Z-directions. The projection optical system 40 is disposed between the mask stage 30 and the plate stage 70, and is configured to guide the exposure light that has passed through the mask 20 onto the plate 60 (substrate) so as to project an image of the pattern formed on the mask 20 onto the plate 60. The plate stage 70 is configured to hold the plate 60, which is the object of exposure, and to drive it in the X-direction, Y-direction, and Z-direction, and in rotational directions about axes parallel to the Z-direction.

[0031] When the exposure apparatus 1 employs a scanning method in which exposure is performed by simultaneously scanning the mask stage 30 and the plate stage 70, the mask stage 30 and the plate stage 70 need to be synchronized with each other. In order to synchronize the two, it is necessary to align the mask stage 30 and the plate stage 70 using the alignment marks drawn on the mask 20 and the alignment marks 601 drawn on the plate 60.

[0032] Therefore, in the exposure apparatus 1, a position measuring apparatus 50 according to the present embodiment for measuring the position of the alignment mark 601 on the plate 60 is provided. Specifically, a control unit (not shown) acquires (measures) the position of the alignment mark 601 in a plane perpendicular to the optical axis of the projection optical system 40 from an image of the alignment mark 601 on the plate 60 acquired by the position measurement device 50 of this embodiment.

[0033] Then, the control unit adjusts the position of the plate stage 70 based on the acquired position of the alignment mark 601 . Specifically, the position measurement device 50 according to this embodiment employs an off-axis system, and the detailed configuration will be described later.

[0034] The exposure apparatus 1 is also provided with a Through The Lens (TTL) or Through The Mirror (TTM) type position measurement apparatus (not shown). Then, the relative position between the position measurement device and the position measurement device 50 according to this embodiment is acquired in advance.

[0035] As a result, by measuring the position of the alignment mark 601 on the plate 60 using the position measurement device 50 according to this embodiment, it is possible to align the alignment mark on the mask 20 with the alignment mark 601 on the plate 60. The position measuring device 50 according to this embodiment may also have a function of measuring the focus of the plate 60 .

[0036] Next, a detailed configuration of the position measurement device 50 according to this embodiment will be described. First, FIG. 10 shows a schematic cross-sectional view of a conventional position measurement apparatus 550 for measuring the position of an alignment mark on a plate 60 provided in an exposure apparatus.

[0037] Specifically, the position measurement device 550 employs an epi-illumination method, and includes an illumination unit 51 and an imaging unit 52. The illumination unit 51 is provided with a light source 511 and an illumination optical system 512 .

[0038] As the light source 511, an LED, a lamp, or the like can be used. Instead of providing the light source 511, light may be guided to the illumination optical system 512 using a light guide such as an optical fiber. The illumination optical system 512 includes a condenser lens, a field stop, and the like, converts the light emitted from the light source 511 into illumination light, and guides the illumination light to the beam splitter 513 .

[0039] The imaging section 52 is provided with a beam splitter 513 , an aperture stop 521 , an objective lens 522 , a relay lens 523 , and an imaging element 542 . The illumination light guided to the beam splitter 513 is reflected by the beam splitter 513 so as to be focused at the position of the aperture stop 521 .

[0040] Thereafter, the illumination light that has passed through the aperture stop 521 is guided by the objective lens 522 to the area on the plate 60 where the alignment mark is formed, thereby illuminating the alignment mark. The light reflected by the illuminated alignment mark on the plate 60 passes through the objective lens 522 , the aperture stop 521 , the beam splitter 513 and the relay lens 523 in this order, and is guided to the imaging surface of the image sensor 542 .

[0041] As a result, an image of the alignment marks on the plate 60 is formed on the imaging surface of the imaging element 542 . Then, the image of the alignment mark formed on the imaging surface of the imaging element 542 is processed, and the position of the alignment mark on the plate 60 is measured.

[0042] Here, it is assumed that an alignment mark 601 as shown in FIG. Specifically, the alignment mark 601 has three rectangles (first portions) formed in the center thereof, which extend in the Y direction and are equally spaced apart from one another in the X direction. In the alignment mark 601, two sets of two rectangles extending in the X direction and spaced apart from each other in the Y direction are formed so as to sandwich the above three rectangles in the Y direction.

[0043] Each rectangle in the alignment mark 601 is formed from a metal film such as chromium, and reflects the irradiated light with a high reflectance. Moreover, a glass portion 602 (second portion) is provided around each rectangle in the alignment mark 601, and the glass portion 602 transmits the irradiated light with high transmittance.

[0044] Here, the rectangle indicated by the dashed lines in FIG. 2 including the above-mentioned rectangles and glass portion 602 will be referred to as alignment mark 601. It is also assumed that the area around the alignment mark 601 on the plate 60 is formed of the glass portion 602 .

[0045] 2 is measured using the conventional position measuring device 550 shown in FIG. At this time, an image as shown in FIG. 11( a ) is formed on the imaging surface of the imaging element 542 in the position measurement device 550 .

[0046] That is, the illumination light irradiated onto the alignment mark 601 is specularly reflected by each rectangle included in the alignment mark 601, so that a bright image of each rectangle is formed on the imaging surface of the imaging element 542. On the other hand, since the illumination light passes through the glass portion 602 and almost no specular reflected light is generated, the light does not reach the inside of the imaging section 52, and the area on the imaging surface of the imaging element 542 corresponding to the glass portion 602 becomes dark. Therefore, a difference in brightness (contrast difference) occurs between the images of each rectangle and the area corresponding to the glass portion 602 in the image formed on the imaging surface of the imaging element 542, so that the alignment mark 601 can be imaged, i.e., the position of the alignment mark 601 can be measured.

[0047] Next, a case will be considered in which the position of the alignment mark 601 shown in FIG. 2 is measured by the oblique incidence illumination method. FIG. 11B shows an image formed on the imaging surface of an imaging element when measuring the position of alignment mark 601 shown in FIG. 2 in a conventional position measurement device that employs an oblique incidence illumination method.

[0048] In a conventional position measurement device that employs an oblique incidence illumination method, an illumination unit is provided so as to make illumination light obliquely incident from a direction non-perpendicular and non-parallel to the plate surface on which alignment mark 601 of plate 60 is formed. Then, imaging sections are provided so as to receive light from the plate surface of the plate 60 at positions facing each other in a direction perpendicular to the plate surface.

[0049] In such an oblique incidence illumination configuration, illumination light that is obliquely incident on the alignment mark 601 at an angle of incidence equal to or greater than the numerical aperture of the imaging optical system provided in the imaging section is specularly reflected in a direction non-perpendicular to the plate surface at the center of each rectangle included in the alignment mark 601. Therefore, a bright image of the central portion of each rectangle of the alignment mark 601 is not formed on the imaging surface of the imaging element provided in the imaging section, that is, the area corresponding to the central portion of each rectangle becomes dark.

[0050] In addition, since the illumination light passes through the glass portion 602 and almost no specular reflected light is generated, the light does not reach the inside of the imaging unit, and the area on the imaging surface of the imaging element corresponding to the glass portion 602 becomes dark. On the other hand, near the ends of each rectangle included in the alignment mark 601, the incident illumination light is scattered.

[0051] A part of the scattered light generated by scattering near the ends of each rectangle reaches the inside of the imaging section and is received on the imaging surface of the imaging element. Therefore, as shown in FIG. 11(b), when the alignment mark 601 is illuminated in a conventional position measurement device that employs an oblique incidence illumination method, the areas on the imaging surface of the image sensor that correspond to the vicinity of the ends of each rectangle included in the alignment mark 601 become bright. In other words, the areas on the imaging surface of the image sensor corresponding to the vicinity of the ends of each rectangle are bright because scattered light is predominantly detected, whereas other areas are dark because no scattered light is generated and no specularly reflected light reaches them.

[0052] Next, a case will be considered in which the position of the alignment mark 601 shown in FIG. 2 is measured using the backside transmitted illumination method. FIG. 11C shows an image formed on the imaging surface of an imaging element when measuring the position of alignment mark 601 shown in FIG. 2 in a conventional position measurement device that employs the backside transmissive illumination method.

[0053] In a conventional position measurement device that employs the backside transmitted illumination method, illumination light is incident from a direction perpendicular to the backside of the plate 60, which is the opposite side of the plate surface on which the alignment mark 601 is formed. An illumination unit is provided so that the illumination light passes through the inside of the plate 60, thereby illuminating the alignment mark 601. Then, imaging sections are provided so as to receive light from the plate surface of the plate 60 at positions facing each other in a direction perpendicular to the plate surface.

[0054] In such a back-side transillumination type configuration, if each rectangle included in the alignment mark 601 is formed of a metal film such as chromium, the illumination light incident on each rectangle is blocked. Therefore, bright images of the rectangles of the alignment mark 601 are not formed on the imaging surface of the imaging element provided in the imaging section, that is, the areas corresponding to the rectangles are dark. On the other hand, since the illumination light passes through the glass portion 602, the light reaches the inside of the imaging portion, and the area on the imaging surface of the imaging element corresponding to the glass portion 602 becomes bright.

[0055] Therefore, as shown in FIG. 11(c), when an alignment mark 601 on a plate 60 is illuminated in a conventional position measurement device that employs a back-side transmitted illumination method, the areas on the imaging surface of the image sensor that correspond to each rectangle included in the alignment mark 601 become dark. On the other hand, the areas on the imaging surface of the imaging element other than the rectangular areas of the alignment mark 601, that is, the areas corresponding to the glass portion 602, become bright.

[0056] FIG. 3A is a schematic cross-sectional view of a position measurement device 50 according to this embodiment. The position measurement device 50 of this embodiment includes an illumination unit 53 that illuminates a plate 60, which is an object (subject), by irradiating the plate 60 with illumination light, and a plate stage 70 (stage) having a mounting surface on which the plate 60 is placed.

[0057] An alignment mark 601 is formed on the plate surface of the plate 60. The position measurement device 50 according to this embodiment also includes an imaging unit 54 that receives light from the plate 60 to obtain an image of the plate 60 .

[0058] As shown in FIG. 3(a), the illumination unit 53 is disposed so as to make illumination light obliquely incident on the plate surface (predetermined surface) of the plate 60 from a direction that is non-perpendicular and non-parallel to the plate surface. In other words, the optical axis of the illumination unit 53 is non-perpendicular and non-parallel to the plate surface of the plate 60 . In other words, the illumination unit 53 is positioned so that the illumination light is incident on the plate surface of the plate 60 at an angle of incidence greater than or equal to the numerical aperture of the imaging optical system 541 provided in the imaging unit 54, so that the specularly reflected light from the alignment mark 601 is not detected in the imaging unit 54.

[0059] Specifically, the illumination unit 53 includes a light source 531 and an illumination optical system 532 . As the light source 531, an LED, a lamp, or the like can be used. Instead of providing the light source 531, light may be guided to the illumination optical system 512 using a light guide such as an optical fiber. It is preferable that the light source 531 is configured so that the amount of light emitted is variable.

[0060] Furthermore, the light source 531 is configured to emit light having a wavelength whose transmittance differs between each rectangle included in the alignment mark 601 and the glass portion 602 . Although the illumination unit 53 is equipped with a single light source 531, the wavelength may be changed by using multiple light sources 531, or the wavelength may be changed by using multiple wavelength cut filters or the like in a single light source 531 that emits light in a wide wavelength band. Furthermore, the light source 531 does not need to be configured to emit light of a single wavelength; in other words, the light emitted from the light source 531 only needs to include light of a predetermined wavelength.

[0061] The illumination optical system 532 includes a condenser lens, a field stop 533, an illumination area adjustment section 534, an aperture stop 535, and a projection lens, and is configured to convert the light emitted from the light source 531 into illumination light and guide the illumination light to the plate surface of the plate 60. Specifically, in the illumination optical system 532, a field stop 533 for restricting the beam diameter of the illumination light is provided at a position optically conjugate with the plate 60, and an aperture stop 535 for adjusting the amount of illumination light is also provided. It is preferable that the illumination optical system 532 further includes a wave plate or the like capable of changing the polarization of the illumination light as required. Moreover, the illumination optical system 532 is preferably configured so that the numerical aperture is adjustable.

[0062] Moreover, the illumination unit 53 is preferably configured to be able to adjust the angle of incidence of the illumination light with respect to the plate surface of the plate 60 so that an image of the alignment mark 601 with high contrast is formed in the imaging unit 54. Specifically, it is preferable that the illumination unit 53 is configured to be able to adjust the exit angle of the illumination light so that the illumination light can be incident on the plate surface of the plate 60 at an incident angle equal to or greater than the numerical aperture of the imaging optical system 541 included in the imaging unit 54. Furthermore, the position measurement device 50 according to this embodiment may be configured to include a plurality of illumination units 53 so that the illumination unit 53 that irradiates the illumination light can be selected according to the optical characteristics of the alignment mark 601.

[0063] For example, if the alignment mark 601 has optical characteristics that are sensitive to the angle of incidence of illumination light in the XY plane, the alignment mark 601 may be illuminated from all directions in the XY plane using a ring-shaped light source 531. Furthermore, for example, in addition to the light source 531 for oblique incidence illumination described above, a light source for epi-illumination for illuminating the alignment mark 601 from a direction perpendicular thereto may be further provided.

[0064] In the position measurement device 50 according to this embodiment, an illumination area adjustment unit 534 for adjusting the illumination area on the plate surface of the plate 60 is provided near the field stop 533. In other words, the illumination area adjustment section 534 is disposed closest to the field stop 533 among the optical elements included in the illumination section 53 . Specifically, the illumination area adjustment unit 534 provided in the position measurement device 50 according to this embodiment is a light blocking unit such as an aperture that blocks a part of the illumination light.

[0065] By rotating the illumination area adjustment section 534, which is such a light blocking section, around the optical axis of the illumination section 53 and positioning it at a predetermined angle, the illumination area on the plate surface of the plate 60 can be adjusted. Moreover, by shifting and arranging the illumination area adjustment section 534 in a predetermined direction perpendicular to the optical axis of the illumination section 53, the illumination area on the plate surface of the plate 60 can be adjusted.

[0066] Furthermore, the illumination area adjustment unit 534 is provided with a plurality of light-shielding sections having different shapes, and a specific light-shielding section can be selected, in other words, the illumination area on the plate surface of the plate 60 can be adjusted by replacing the light-shielding section. In addition to the above configuration, the illumination area on the alignment mark 601 may be adjusted by driving the plate stage 70 .

[0067] The imaging section 54 includes an imaging element 542 that receives light from the plate 60, and an imaging optical system 541 that includes an objective lens, an aperture stop, and a relay lens and guides light from the plate 60 to the imaging element 542, and has an optical axis perpendicular to the plate surface of the plate 60.

[0068] The plate stage 70 is a stage having a drive shaft that is used in the exposure apparatus 1 that employs the scan method, step method, or the like as described above, and is provided with a vacuum chuck or the like for adsorbing and holding the plate 60. Furthermore, while the plate stage 70 reflects and scatters the illumination light in the position measurement device 50 of this embodiment, it is preferable that the plate stage 70 has a highly flat mounting surface that is formed using a material with a low thermal expansion coefficient and is less likely to reflect or scatter the exposure light in the exposure apparatus 1.

[0069] FIG. 3B shows a state in which the illumination area on the plate surface of the plate 60 is illuminated without being adjusted by the illumination area adjustment unit 534 in the position measurement device 50 according to this embodiment. At this time, as shown in FIG. 3( b ), the illumination light from the illumination unit 53 is incident on both the alignment mark 601 on the plate surface of the plate 60 and the glass portion 602 around the alignment mark 601 .

[0070] It should be noted that in FIG. 3(b), the alignment mark 601 is shown enlarged to make it easier to see the specularly reflected light and scattered light from the alignment mark 601, and that in reality, the illumination light 55 from the illumination unit 53 is incident on the entire alignment mark 601. Moreover, the arrows in FIG. 3(b) indicate the direction in which each representative light ray travels. The same applies to Figures 5(a) and (b).

[0071] First, of the illumination light 55 contained in the illumination light from the illumination unit 53 that directly enters the alignment mark 601, the light that enters the center of each rectangle contained in the alignment mark 601 is reflected by the center of each rectangle to generate specularly reflected light 551. The generated specularly reflected light 551 has a reflection angle equal to or greater than the numerical aperture of the imaging optical system 541 provided in the imaging section 54 , and therefore does not reach the imaging surface of the imaging element 542 . Therefore, a bright image is not formed in the center of each rectangle on the imaging surface of the imaging element 542.

[0072] Next, of the illumination light 55 contained in the illumination light from the illumination unit 53 that is directly incident on the alignment mark 601, light that is incident near the ends of each rectangle contained in the alignment mark 601 is scattered near the ends of each rectangle to generate scattered light 552. A part of the generated scattered light 552 has a scattering angle less than the numerical aperture of the imaging optical system 541 provided in the imaging section 54, and thus reaches the imaging surface of the imaging element 542 and is received.

[0073] Therefore, the areas on the imaging surface of the image sensor 542 that correspond to the ends of each rectangle become brighter. That is, from the specularly reflected light 551 and the scattered light 552, the same results as those obtained by the oblique incidence illumination method described above with reference to FIG. 11(b) can be obtained.

[0074] Next, most of the illumination light 56 ​​that is included in the illumination light from the illumination unit 53 and that is incident on the glass portion 602 around the alignment mark 601 is transmitted through the glass portion 602 on which it is incident. As a result, the incident light 561 reaches the surface of the plate stage 70 on which the plate 60 is placed.

[0075] The incident light 561 is reflected by the mounting surface of the plate stage 70 to generate reflected light 562, and is scattered by the mounting surface to generate scattered light 563. At this time, since the plate 60 has a thickness, a part of each of the reflected light 562 and the scattered light 563 enters each rectangle included in the alignment mark 601 from below in the Z direction.

[0076] Also, when viewed in the XY plane, a portion of each of the reflected light 562 and scattered light 563 undergoes total reflection and scattering multiple times inside the plate 60, spreading in various directions and thereby entering each rectangle included in the alignment mark 601 from various directions. In this way, a portion of each of the reflected light 562 and the scattered light 563 indirectly illuminates the alignment mark 601 .

[0077] Then, of the reflected light 562 and scattered light 563, the light 564 that is transmitted through the plate surface of the plate 60 and that travels in a direction that forms an angle less than the numerical aperture of the imaging optical system 541 with respect to the normal to the plate surface of the plate 60 reaches the imaging surface of the imaging element 542. On the other hand, light 565 out of reflected light 562 and scattered light 563 is blocked by being incident on each rectangle included in alignment mark 601 and does not reach the imaging surface of imaging element 542 .

[0078] Therefore, the areas on the imaging surface of the imaging element 542 that correspond to the glass portion 602 other than the rectangles included in the alignment mark 601 become brighter. That is, the reflected light 562 and the scattered light 563 produce the same results as those of the backside transmission illumination method described above with reference to FIG. 11(c).

[0079] As described above, in the position measurement device 50 according to this embodiment, when the illumination area on the plate surface of the plate 60 is illuminated without being adjusted by the illumination area adjustment unit 534, an image such as that shown in FIG. 4 is obtained on the imaging surface of the image sensor 542. That is, FIG. 4 shows images formed on the imaging surface of the image sensor 542 by both the above-mentioned oblique incidence illumination method and back surface transmitted illumination method, and it can be seen that there is a decrease in contrast between each rectangle included in the alignment mark 601 and the glass portion 602 other than each rectangle.

[0080] If an attempt is made to measure the position of the alignment mark 601 based on such a low-contrast image, there is a possibility that undesirable results such as erroneous measurement will occur. That is, there is a risk that the accuracy of alignment of the plate 60 will decrease due to erroneous measurement of the position of the alignment mark 601, and that the overlay accuracy when the exposure apparatus 1 exposes the plate 60 will decrease.

[0081] Therefore, in the position measurement device 50 according to this embodiment, an illumination area adjustment unit 534 for adjusting the illumination area on the plate surface of the plate 60 is provided near the field stop 533 included in the illumination unit 53. This allows the alignment mark 601 to be illuminated based on a selected one of the oblique incidence illumination method and the back surface transmitted illumination method while using the same light source 531, thereby making it possible to obtain a high contrast image of the alignment mark 601 on the imaging surface of the imaging element 542.

[0082] FIG. 5A shows how the illumination area on the plate surface of the plate 60 adjusted by the illumination area adjustment unit 534 in the position measurement device 50 according to this embodiment is illuminated. Specifically, in the configuration shown in FIG. 5( a ), the illumination area adjustment unit 534 blocks illumination light 56 ​​from entering the glass portion 602 around the alignment mark 601 . As a result, the illumination area on the plate surface of the plate 60 is illuminated only by the illumination light 55 that is directly incident on the alignment mark 601 .

[0083] In this case, the above-mentioned oblique incidence illumination method is selected, and the reflected light 562 and scattered light 563 illuminating the alignment mark 601 from below can be reduced. Therefore, scattered light 552 generated by scattering near the ends of each rectangle included in the alignment mark 601 reaches the imaging surface of the image sensor 542 and is received, resulting in a high-contrast image as shown in Figure 11(b), in which only the ends of each rectangle are bright.

[0084] FIG. 5B shows how another illumination area on the plate surface of the plate 60 adjusted by the illumination area adjustment unit 534 in the position measurement device 50 according to this embodiment is illuminated. Specifically, in the configuration shown in FIG. 5( b ), the illumination area adjustment unit 534 blocks the illumination light 55 that is directly incident on the alignment mark 601 . As a result, the illumination area on the plate surface of the plate 60 is illuminated only by the illumination light 56 ​​incident on the glass portion 602 around the alignment mark 601 .

[0085] In this case, the above-mentioned back-surface transmitted illumination method is selected, and the illumination light 55 illuminating the alignment mark 601 from above can be reduced. Therefore, of the reflected light 562 and scattered light 563 generated on the placement surface of the plate 60 on the plate stage 70, light 564 that passes through the plate surface of the plate 60 reaches the imaging surface of the imaging element 542 and is received. This results in a high-contrast image as shown in FIG. 11(c), in which only the areas other than the rectangles included in the alignment mark 601 are bright.

[0086] In the position measurement device 50 according to this embodiment, as described above, the illumination area on the plate surface can be switched so that illumination light is incident only on the alignment mark 601 or only on the glass portion 602 surrounding the alignment mark 601. In other words, in the position measurement device 50 according to this embodiment, the illumination area on the plate surface by the illumination light can be adjusted so that more of the illumination light is incident on one of the first and second areas on the plate surface.

[0087] For example, the illumination area on the plate surface is adjusted by the illumination area adjustment unit 534 so that more illumination light is incident on the first area between a first area including at least a portion of the alignment mark 601 and a second area including at least a portion of the glass portion 602 (first adjustment). This allows the alignment mark 601 to be illuminated by an oblique incidence illumination method, making it possible to obtain an image of the plate surface including the alignment mark 601 according to the oblique incidence illumination method.

[0088] In addition, the illumination area on the plate surface is adjusted by the illumination area adjustment unit 534 so that more illumination light is incident on the second area out of the first area including at least a portion of the alignment mark 601 and the second area including at least a portion of the glass portion 602 (second adjustment). This allows the alignment mark 601 to be illuminated by a backside transmission illumination method, making it possible to obtain an image of the plate surface including the alignment mark 601 according to the backside transmission illumination method. In this manner, the illumination area adjustment section 534 provided in the illumination section 53 in the position measurement device 50 according to this embodiment is configured to be able to execute the first adjustment and the second adjustment.

[0089] That is, by illuminating the alignment mark 601 with the same light source 531 using an illumination method selected from the oblique incidence illumination method and the back surface transmission illumination method, a high contrast image of the alignment mark 601 can be acquired. In this case, a control unit (not shown) is provided, and based on parameters (input parameters) input to the control unit, the control unit selects one of the oblique incidence illumination method and the back-transmitted illumination method, and causes the imaging unit 54 to acquire an image of the plate 60.

[0090] Such parameters include, for example, the plate 60, the photosensitive agent applied to the plate surface of the plate 60, and the materials of each rectangle and glass portion 602 included in the alignment mark 601, specifically, optical properties such as reflectance and transmittance for incident light. For example, if the plate 60 does not have a portion that transmits the illumination light, e.g., if it is made of metal, the alignment mark 601 cannot be illuminated by the back-side transmitted illumination method, so the oblique incidence illumination method must be selected.

[0091] On the other hand, when the plate 60 has a portion that transmits illumination light, such as the glass portion 602, one of the oblique incidence illumination method and the backside transmitted illumination method can be selected in order to obtain a high contrast image according to the optical properties described above. Furthermore, when it is not possible to select either the oblique incidence illumination method or the back surface transmitted illumination method based on the above optical properties, it is also possible to cause the imaging unit 54 to acquire images of the plate 60 using both methods, and select the image with the higher contrast from among the two images.

[0092] Moreover, the position measurement device 50 according to this embodiment can be combined with the above-mentioned epi-illumination method. In other words, by providing the above-mentioned illumination unit 53 in a position measurement device that employs, for example, an epi-illumination method, it is possible to provide a position measurement device that can easily switch between three illumination methods, namely, epi-illumination method, oblique incidence illumination method, and back-transmitted illumination method.

[0093] As described above, in the position measurement device 50 according to this embodiment, the illumination area on the plate surface of the plate 60 can be adjusted by providing the illumination unit 53 with the illumination area adjustment unit 534, which is a shading unit that blocks part of the illumination light. Thus, by illuminating the alignment mark 601 with an illumination method selected from the oblique incidence illumination method and the back surface transmission illumination method, a high contrast image of the alignment mark 601 can be acquired.

[0094] That is, in this embodiment, it is possible to provide a position measurement apparatus 50 that can employ both the back surface transmission illumination method and the oblique incidence illumination method within the constraints of the limited space inside the exposure apparatus 1. This makes it possible to provide an exposure apparatus 1 that is equipped with a position measuring device 50 that has a simple, low-cost configuration and high measurement robustness.

[0095] When illumination is performed by the back-side transmitted illumination method as shown in FIG. 5(b) in the position measurement device 50 according to this embodiment, it is preferable that the illumination light 56 ​​is not blocked as much as possible before it reaches the mounting surface of the plate 60 on the plate stage 70. For example, if a portion of the illumination light 56 ​​is blocked by a rectangle contained in another alignment mark 601 before reaching the mounting surface of the plate 60 on the plate stage 70, reflected light 562 and scattered light 563 that are missing that portion will be generated.

[0096] Then, when the alignment mark 601 is illuminated by the partially missing reflected light 562 and the scattered light 563, uneven illuminance occurs in the image formed on the imaging surface of the imaging element 542. Therefore, when illuminating a specific alignment mark 601 using the backside transmitted illumination method, it is preferable that the illumination light 56 ​​passes through the glass portion 602 on the plate surface of the plate 60 on which no other alignment mark 601 is formed.

[0097] Further, in the above, an example was shown in which the position measuring device 50 according to this embodiment is provided in the exposure apparatus 1, but the present invention is not limited to this, and it is also possible to provide it in a pattern forming apparatus such as an imprint apparatus or a drawing apparatus.

[0098] Here, the imprinting device is a device that brings an imprinting material supplied onto a substrate into contact with a mold, and then applies energy for hardening to the imprinting material to form a pattern of the hardened material to which the pattern of the mold is transferred. Moreover, a drawing apparatus is an apparatus that forms a pattern (latent image pattern) on a substrate by drawing on the substrate with a charged particle beam (electron beam) or a laser beam.

[0099] Furthermore, this embodiment is not limited to being applied to the position measurement device 50, but can also be applied to various types of observation devices such as microscopes. Furthermore, the position measurement device 50 according to this embodiment is not limited to being provided in the exposure apparatus 1 that employs the scan method, but may be provided in an exposure apparatus that employs another exposure method, such as a step method.

[0100] [Second embodiment] FIG. 6A shows a schematic cross-sectional view of a position measurement device 150 according to the second embodiment. The position measurement device 150 of this embodiment has the same configuration as the position measurement device 50 of the first embodiment, except that an illumination area adjustment unit 536 is provided instead of an illumination area adjustment unit 534. Therefore, the same components are given the same reference numbers and their descriptions are omitted.

[0101] Specifically, in the position measurement device 150 according to this embodiment, the illumination area adjustment section 536 formed of a transmission section in the illumination section 53 is provided in the vicinity of the field stop 533 . In other words, the illumination area adjustment section 536 is disposed closest to the field stop 533 among the optical elements included in the illumination section 53 . More specifically, the illumination area adjustment unit 536 is, for example, a flat plate (transmitting element) that transmits light emitted from the light source 531, and is configured to be rotatable around a rotation axis perpendicular to the optical axis of the illumination optical system 532.

[0102] By rotating the illumination area adjustment unit 536 around the rotation axis, the illumination light can be incident on a position on the plate surface of the plate 60 that is shifted in a direction perpendicular to both the optical axis of the illumination optical system 532 and the rotation axis. That is, in the position measurement device 150 according to this embodiment, the illumination area can be adjusted by changing the irradiation position of the illumination light on the plate surface of the plate 60.

[0103] FIG. 6B shows a state in which the illumination area on the plate surface of the plate 60 is illuminated without being adjusted by the illumination area adjustment unit 536 in the position measurement device 150 according to this embodiment. At this time, as shown in FIG. 6( b ), the illumination light from the illumination unit 53 is incident on both the alignment mark 601 on the plate surface of the plate 60 and the glass portion 602 around the alignment mark 601 .

[0104] It should be noted that in FIG. 6(b), the alignment mark 601 is shown enlarged to make it easier to see the specularly reflected light and scattered light from the alignment mark 601, and that in reality, illumination light 55 from the illumination unit 53 is incident on the entire alignment mark 601. Moreover, the arrows in FIG. 6(b) indicate the traveling direction of each representative light ray. The same applies to Figures 7(a) and (b).

[0105] In this case, as described using FIG. 3(b) in the position measurement device 50 according to the first embodiment, both illumination light 55 and 56 are incident, generating specular reflected light 551, scattered light 552, reflected light 562, and scattered light 563. Then, a part of the scattered light 552 and a part of the reflected light 562 and the scattered light 563 that is transmitted through the plate surface of the plate 60 (light 564) reach the imaging surface of the imaging element 542 and are received.

[0106] In this manner, when the illumination area on the plate surface of the plate 60 is illuminated without being adjusted by the illumination area adjustment unit 536 in the position measurement device 150 according to this embodiment, an image such as that shown in FIG. 4 is obtained on the imaging surface of the image sensor 542. In other words, when images are formed on the imaging surface of the imaging element 542 using both the above-mentioned oblique incidence illumination method and back surface transmitted illumination method, the contrast between each rectangle included in the alignment mark 601 and the glass portion 602 other than each rectangle is reduced.

[0107] If an attempt is made to measure the position of the alignment mark 601 based on such a low-contrast image, there is a possibility that undesirable results such as erroneous measurement will occur. That is, there is a risk that the accuracy of alignment of the plate 60 will decrease due to erroneous measurement of the position of the alignment mark 601, and that the overlay accuracy when the exposure apparatus 1 exposes the plate 60 will decrease.

[0108] Therefore, in the position measurement device 150 according to this embodiment, an illumination area adjustment unit 536 for adjusting the illumination area on the plate surface of the plate 60 is provided near the field stop 533 included in the illumination unit 53. This makes it possible to illuminate the alignment mark 601 using the same light source 531 based on a selected one of the oblique incidence illumination method and the backside transmission illumination method. Therefore, a high-contrast image of the alignment mark 601 can be acquired on the imaging surface of the imaging element 542.

[0109] FIG. 7A shows how the illumination area on the plate surface of the plate 60 adjusted by the illumination area adjustment unit 536 in the position measurement device 150 according to this embodiment is illuminated. Specifically, in the configuration shown in FIG. 7(a), the illumination area on the plate surface of the plate 60 is adjusted by rotating the illumination area adjustment unit 536 so that the illumination light from the illumination unit 53 is directly incident on the alignment mark 601. In other words, the illumination area adjustment unit 536 does not generate illumination light 56 ​​that is incident on the glass portion 602 surrounding the alignment mark 601, but instead generates only illumination light 55 that is directly incident on the alignment mark 601, thereby illuminating the illumination area.

[0110] In this case, the above-mentioned oblique incidence illumination method is selected, and the reflected light 562 and scattered light 563 illuminating the alignment mark 601 from below can be reduced. Therefore, scattered light 552 generated by scattering near the ends of each rectangle included in the alignment mark 601 reaches the imaging surface of the image sensor 542 and is received, resulting in a high-contrast image as shown in Figure 11(b), in which only the ends of each rectangle are bright.

[0111] FIG. 7B shows how another illumination area on the plate surface of the plate 60 adjusted by the illumination area adjustment unit 536 in the position measurement device 150 according to this embodiment is illuminated. Specifically, in the configuration shown in FIG. 7(b), the illumination area on the plate surface of the plate 60 is adjusted by rotating the illumination area adjustment unit 536 so that the illumination light from the illumination unit 53 is incident on the glass portion 602 surrounding the alignment mark 601. In other words, the illumination area adjustment unit 536 does not generate illumination light 55 that directly enters the alignment mark 601, but instead generates only illumination light 56 ​​that enters the glass portion 602 surrounding the alignment mark 601, thereby illuminating the illumination area.

[0112] In this case, the above-mentioned back-surface transmitted illumination method is selected, and the illumination light 55 illuminating the alignment mark 601 from above can be reduced. Therefore, of the reflected light 562 and scattered light 563 generated on the placement surface of the plate 60 on the plate stage 70, light 564 that passes through the plate surface of the plate 60 reaches the imaging surface of the imaging element 542 and is received. This results in a high-contrast image as shown in FIG. 11(c), in which only the areas other than the rectangles included in the alignment mark 601 are bright.

[0113] In the position measurement device 150 according to this embodiment, as described above, the illumination area on the plate surface can be switched so that illumination light is incident only on the alignment mark 601 or only on the glass portion 602 surrounding the alignment mark 601. That is, by illuminating the alignment mark 601 with the same light source 531 using an illumination method selected from the oblique incidence illumination method or the back surface transmission illumination method, a high contrast image of the alignment mark 601 can be acquired.

[0114] As described above, in the position measurement device 150 according to this embodiment, the illumination area on the plate surface of the plate 60 can be adjusted by providing the illumination unit 53 with the illumination area adjustment unit 536, which is a transmissive unit for shifting the optical axis of the illumination unit 53 in a direction perpendicular to the optical axis of the illumination unit 53. This makes it possible to obtain a high-contrast image of the alignment mark 601 by illuminating the alignment mark 601 with an illumination method selected from the oblique incidence illumination method and the back surface transmission illumination method.

[0115] In addition, in the position measurement device 150 of this embodiment, all of the light from the light source 531 can be incident on the plate surface of the plate 60 without blocking a portion of it, so that it is possible to illuminate a wide illumination area with higher illumination efficiency than the position measurement device 50 of the first embodiment. Furthermore, in the position measurement device 150 of this embodiment, in addition to the illumination area adjustment unit 536 consisting of a rotatable flat plate, an illumination area adjustment unit 534 consisting of a light-shielding unit used in the position measurement device 50 of the first embodiment may be further provided.

[0116] [Third embodiment] FIG. 8A shows a schematic cross-sectional view of a position measurement device 250 according to the third embodiment. The position measurement device 250 of this embodiment has the same configuration as the position measurement device 50 of the first embodiment, except that an illumination area adjustment unit 537 is provided instead of the illumination area adjustment unit 534. Therefore, the same components are given the same reference numbers and their descriptions are omitted.

[0117] Specifically, in the position measurement device 250 according to this embodiment, the illumination area adjustment unit 537 formed of a reflecting portion in the illumination unit 53 is provided in the vicinity of the aperture stop 535 . In other words, the illumination area adjustment section 537 is disposed closest to the aperture stop 535 among the optical elements included in the illumination section 53 . More specifically, the illumination area adjustment unit 537 is, for example, a galvanometer mirror (reflective element) that reflects light emitted from the light source 531, and is configured to be rotatable around an axis perpendicular to both the optical axis of the illumination optical system 532 and the normal to the reflecting surface.

[0118] Then, by rotating the illumination area adjustment unit 537, i.e., by adjusting the angle of the reflecting surface, the angle of the illumination light reflected by the illumination area adjustment unit 537 can be changed, thereby changing the irradiation position of the illumination light on the plate surface of the plate 60. That is, in the position measurement device 250 according to this embodiment, the illumination area can be adjusted by changing the irradiation position of the illumination light on the plate surface of the plate 60.

[0119] FIG. 8B shows a state in which the illumination area on the plate surface of the plate 60 is illuminated without being adjusted by the illumination area adjustment unit 537 in the position measurement device 250 according to this embodiment. At this time, as shown in FIG. 8( b ), the illumination light from the illumination unit 53 is incident on both the alignment mark 601 on the plate surface of the plate 60 and the glass portion 602 around the alignment mark 601 .

[0120] It should be noted that in Figure 8(b), the alignment mark 601 is shown enlarged to make it easier to see the specularly reflected light and scattered light from the alignment mark 601, and that in reality, the illumination light 55 from the illumination unit 53 is incident on the entire alignment mark 601. Moreover, the arrows in FIG. 8(b) indicate the traveling direction of each representative light ray. The same applies to Figures 9(a) and (b).

[0121] In this case, as described using FIG. 3(b) in the position measurement device 50 according to the first embodiment, both illumination light 55 and 56 are incident, generating specular reflected light 551, scattered light 552, reflected light 562, and scattered light 563. Then, a part of the scattered light 552 and a part of the reflected light 562 and the scattered light 563 that is transmitted through the plate surface of the plate 60 (light 564) reach the imaging surface of the imaging element 542 and are received.

[0122] In this way, when the illumination area of ​​the alignment mark 601 is illuminated without being adjusted by the illumination area adjustment unit 537 in the position measurement device 250 according to this embodiment, an image such as that shown in FIG. 4 is obtained on the imaging surface of the image sensor 542. In other words, when images are formed on the imaging surface of the imaging element 542 using both the above-mentioned oblique incidence illumination method and back surface transmitted illumination method, the contrast between each rectangle included in the alignment mark 601 and the glass portion 602 other than each rectangle is reduced.

[0123] If an attempt is made to measure the position of the alignment mark 601 based on such a low-contrast image, undesirable results such as erroneous measurements may occur. That is, there is a risk that the accuracy of alignment of the plate 60 will decrease due to erroneous measurement of the position of the alignment mark 601, and that the overlay accuracy when the exposure apparatus 1 exposes the plate 60 will decrease.

[0124] Therefore, in the position measurement device 250 according to this embodiment, an illumination area adjustment unit 537 for adjusting the illumination area on the plate surface of the plate 60 is provided near the aperture stop 535 included in the illumination unit 53. This makes it possible to illuminate the alignment mark 601 using the same light source 531 based on a selected one of the oblique incidence illumination method and the backside transmission illumination method. Therefore, a high-contrast image of the alignment mark 601 can be acquired on the imaging surface of the imaging element 542.

[0125] FIG. 9A shows how the illumination area on the plate surface of the plate 60 adjusted by the illumination area adjustment unit 537 in the position measurement device 250 according to this embodiment is illuminated. Specifically, in the configuration shown in FIG. 9(a), the illumination area on the plate surface of the plate 60 is adjusted by rotating the illumination area adjustment unit 537 so that the illumination light from the illumination unit 53 is directly incident on the alignment mark 601. In other words, the illumination area adjustment unit 537 does not generate illumination light 56 ​​that is incident on the glass portion 602 surrounding the alignment mark 601, but instead generates only illumination light 55 that is directly incident on the alignment mark 601, thereby illuminating the illumination area.

[0126] In this case, the above-mentioned oblique incidence illumination method is selected, and the reflected light 562 and scattered light 563 illuminating the alignment mark 601 from below can be reduced. Therefore, scattered light 552 generated by scattering near the ends of each rectangle included in the alignment mark 601 reaches the imaging surface of the image sensor 542 and is received, resulting in a high-contrast image as shown in Figure 11(b), in which only the ends of each rectangle are bright.

[0127] FIG. 9B shows how another illumination area on the plate surface of the plate 60 adjusted by the illumination area adjustment unit 537 in the position measurement device 250 according to this embodiment is illuminated. Specifically, in the configuration shown in FIG. 9(b), the illumination area on the plate surface of the plate 60 is adjusted by rotating the illumination area adjustment unit 537 so that the illumination light from the illumination unit 53 is incident on the glass portion 602 surrounding the alignment mark 601. In other words, the illumination area adjustment unit 537 does not generate illumination light 55 that directly enters the alignment mark 601, but instead generates only illumination light 56 ​​that enters the glass portion 602 surrounding the alignment mark 601, thereby illuminating the illumination area.

[0128] In this case, the above-mentioned back-surface transmitted illumination method is selected, and the illumination light 55 illuminating the alignment mark 601 from above can be reduced. Therefore, of the reflected light 562 and scattered light 563 generated on the placement surface of the plate 60 on the plate stage 70, light 564 that passes through the plate surface of the plate 60 reaches the imaging surface of the imaging element 542 and is received. This results in a high-contrast image as shown in FIG. 11(c), in which only the areas other than the rectangles included in the alignment mark 601 are bright.

[0129] In the position measurement device 250 according to this embodiment, as described above, the illumination area on the plate surface can be switched so that illumination light is incident only on the alignment mark 601 or only on the glass portion 602 surrounding the alignment mark 601. That is, by illuminating the alignment mark 601 with the same light source 531 using an illumination method selected from the oblique incidence illumination method or the back surface transmission illumination method, a high contrast image of the alignment mark 601 can be acquired.

[0130] As described above, in the position measurement device 250 according to this embodiment, the illumination area on the plate surface of the plate 60 can be adjusted by providing the illumination area adjustment unit 537, which is a reflecting unit that reflects illumination light, in the illumination unit 53. Thus, by illuminating the alignment mark 601 with an illumination method selected from the oblique incidence illumination method and the back surface transmission illumination method, a high contrast image of the alignment mark 601 can be acquired.

[0131] In addition, in the position measurement device 250 of this embodiment, all of the light from the light source 531 can be incident on the plate surface of the plate 60 without blocking a portion of it, so that it is possible to illuminate a wide illumination area with higher illumination efficiency than the position measurement device 50 of the first embodiment. Moreover, in the position measurement device 250 according to this embodiment, the illumination area adjustment unit 537 changes the reflection angle of the illumination light, thereby changing the irradiation position of the illumination light on the plate surface of the plate 60. Therefore, the illumination area can be adjusted at higher speed than the position measurement device 50 according to the first embodiment and the position measurement device 150 according to the second embodiment.

[0132] Furthermore, the position measurement device 250 according to this embodiment may further include the illumination area adjustment unit 534 in the position measurement device 50 according to the first embodiment or the illumination area adjustment unit 536 in the position measurement device 150 according to the second embodiment. That is, in addition to arranging the illumination area adjustment section 537 near the aperture stop 535 , the illumination area adjustment section 534 and the illumination area adjustment section 536 may be arranged near the field stop 533 .

[0133] Although the preferred embodiments have been described above, the present invention is not limited to these embodiments and various modifications and changes are possible within the scope of the gist thereof.

[0134] [Production method] The method for manufacturing an article according to this embodiment includes a step of exposing a substrate, such as a wafer or a glass substrate, coated with a photosensitive agent, using an exposure apparatus 1 equipped with a position measurement apparatus according to any of the first to third embodiments. The articles in question include semiconductor integrated circuit (IC) elements, liquid crystal display elements, and microelectromechanical systems (MEMS), etc.

[0135] The method for manufacturing an article according to this embodiment also includes a step of developing the exposed substrate (photosensitive agent) and other well-known steps of treating the developed substrate. The other well-known processes include etching, photoresist peeling, dicing, bonding, packaging, and the like.

[0136] According to the method for manufacturing an article according to this embodiment, it is possible to manufacture an article of higher quality than before.

[0137] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) An imaging device comprising: an illumination area adjustment unit capable of performing a first adjustment of adjusting an illumination area of ​​an object by illumination light so that illumination light including light of a predetermined wavelength is incident on a first area out of a first area and a second area of ​​the object; and a second adjustment of adjusting the illumination area so that illumination light is incident on a second area out of the first area and the second area; an illumination unit that incidents illumination light on the object; an imaging unit that obtains an image of the object by receiving light from the object; and a stage on which the object is placed and which has a mounting surface that reflects light of the predetermined wavelength. (Configuration 2) An imaging device according to configuration 1, characterized in that the object includes a first portion that scatters incident light of a predetermined wavelength, and the first region includes at least a portion of the first portion. (Configuration 3) The imaging device according to configuration 2, wherein the imaging section obtains an image of the object by receiving light of a predetermined wavelength scattered by the first portion in the first adjustment. (Configuration 4) An imaging device according to configuration 2 or 3, characterized in that the imaging unit includes an imaging element that receives light from the object and an imaging optical system that guides the light from the object to the imaging element, and the illumination unit causes illumination light to be incident on the object at an angle of incidence that is equal to or greater than the numerical aperture of the imaging optical system in the first adjustment. (Configuration 5) An imaging device described in any one of configurations 2 to 4, characterized in that the object includes a second portion that transmits incident light of a specific wavelength, and the second region includes at least a portion of the second portion. (Configuration 6) The imaging device described in Configuration 5, characterized in that the imaging unit obtains an image of the object by receiving light of a predetermined wavelength that passes through the second portion during the second adjustment, is reflected by the mounting surface, and then passes through the second portion. (Configuration 7) The imaging device according to any one of configurations 1 to 6, wherein the illumination area adjustment unit includes a light blocking unit that blocks a portion of the illumination light. (Configuration 8) An imaging device described in Configuration 7, characterized in that the illumination unit is arranged at a position optically conjugate with the object and includes a field diaphragm that regulates the beam diameter of the illumination light, and the shading unit is arranged closest to the field diaphragm among the optical elements included in the illumination unit. (Configuration 9) An imaging device described in configuration 7 or 8, characterized in that the illumination area adjustment unit adjusts the illumination area by rotating the shading unit around the optical axis of the illumination unit, shifting the shading unit in a predetermined direction perpendicular to the optical axis of the illumination unit, or replacing the shading unit with another shading unit. (Configuration 10) An imaging device described in any one of configurations 1 to 9, characterized in that the illumination area adjustment unit includes a transmission unit that transmits illumination light so as to shift the optical axis of the illumination unit in a predetermined direction perpendicular to the optical axis of the illumination unit. (Configuration 11) An imaging device described in Configuration 10, characterized in that the illumination unit is arranged at a position optically conjugate with the object and includes a field stop that regulates the beam diameter of the illumination light, and the transmission unit is arranged closest to the field stop among the optical elements included in the illumination unit. (Configuration 12) An imaging device described in configuration 10 or 11, characterized in that the illumination area adjustment unit adjusts the illumination area by rotating the transmission unit around an axis perpendicular to both the specified direction and the optical axis of the illumination unit. (Configuration 13) The imaging device according to any one of configurations 1 to 12, wherein the illumination area adjustment section includes a reflecting section that reflects the illumination light. (Configuration 14) An imaging device according to Configuration 13, characterized in that the illumination unit includes an aperture stop that adjusts the amount of illumination light, and the reflection unit is disposed closest to the aperture stop among the optical elements included in the illumination unit. (Configuration 15) The imaging device according to configuration 13 or 14, wherein the illumination area adjustment section adjusts the illumination area by adjusting the angle of the reflecting surface of the reflecting section. (Configuration 16) An imaging device described in any one of configurations 1 to 15, characterized in that the illumination unit includes a light source that emits illumination light and an illumination optical system that guides the illumination light from the light source to an object, and the illumination unit is configured to be able to adjust at least one of the angle of incidence of the illumination light with respect to the object, the numerical aperture of the illumination optical system, the wavelength of the illumination light, the amount of the illumination light, and the polarization of the illumination light. (Configuration 17) The imaging device according to any one of configurations 1 to 16, wherein the number of light sources included in the illumination section for emitting illumination light is one. (Configuration 18) An imaging device described in any one of configurations 1 to 17, characterized in that the object has a specified surface including a first region and a second region, and the optical axis of the illumination unit is non-perpendicular and non-parallel to the specified surface. (Configuration 19) The imaging device according to configuration 18, wherein the optical axis of the imaging section is perpendicular to the predetermined plane. (Configuration 20) An imaging device according to any one of configurations 1 to 19, characterized in that it includes a control unit that causes the imaging unit to acquire an image in one of the first adjustment and the second adjustment selected based on an input parameter, or causes the imaging unit to acquire an image in each of the first adjustment and the second adjustment. (Configuration 21) The imaging device according to configuration 20, wherein the input parameters include the material of the object. (Configuration 22) An exposure apparatus that projects an image of a pattern of an original onto a substrate and exposes the substrate, comprising: a projection optical system that guides exposure light that has passed through the original onto the substrate, an imaging device according to any one of configurations 1 to 21 that acquires an image of the substrate on which an alignment mark is formed, and a control unit that acquires the position of the alignment mark in a plane perpendicular to the optical axis of the projection optical system from an image of the alignment mark included in the image of the substrate acquired by the imaging device, and adjusts the position of a stage based on the acquired position. (Method 1) A method for manufacturing an article, comprising the steps of exposing a substrate by the exposure apparatus according to Configuration 22, and developing the exposed substrate. [Explanation of symbols]

[0138] 50, 150, 250 Position measurement device (imaging device) 53 Lighting Department 54 Imaging unit 60 Plate (Object) 70 Plate Stage (Stage) 534, 536, 537 Lighting area adjustment section

Claims

1. an illumination unit including an illumination area adjustment unit capable of performing a first adjustment of adjusting an illumination area of ​​the object by illumination light such that illumination light including light of a predetermined wavelength is incident on the first area out of a first area and a second area of ​​the object, and a second adjustment of adjusting the illumination area such that illumination light is incident on the second area out of the first area and the second area, and causing the illumination light to be incident on the object; an imaging unit that receives light from the object to obtain an image of the object; a stage having a mounting surface on which the object is placed and which reflects light of the predetermined wavelength; An imaging device comprising:

2. the object includes a first portion that scatters incident light of the predetermined wavelength; The imaging device according to claim 1 , wherein the first region includes at least a part of the first portion.

3. The imaging device according to claim 2 , wherein the imaging section obtains the image of the object by receiving light of the predetermined wavelength scattered by the first portion during the first adjustment.

4. the imaging unit includes an imaging element that receives light from the object, and an imaging optical system that guides the light from the object to the imaging element; 3 . The imaging apparatus according to claim 2 , wherein the illumination unit causes the illumination light to be incident on the object at an angle of incidence equal to or greater than a numerical aperture of the imaging optical system in the first adjustment.

5. the object includes a second portion that transmits incident light of the predetermined wavelength; The imaging device according to claim 2 , wherein the second region includes at least a part of the second portion.

6. The imaging device according to claim 5, characterized in that the imaging unit obtains the image of the object by receiving light of the specified wavelength that has passed through the second portion during the second adjustment, been reflected by the placement surface, and then passed through the second portion.

7. The imaging device according to claim 1 , wherein the illumination area adjustment unit includes a light blocking unit that blocks a part of the illumination light.

8. the illumination unit is disposed at a position optically conjugate with the object and includes a field stop that regulates a beam diameter of the illumination light; The imaging device according to claim 7 , wherein the light blocking portion is disposed closest to the field stop among the optical elements included in the illumination portion.

9. 8. The imaging device according to claim 7, wherein the illumination area adjustment unit adjusts the illumination area by rotating the light-shielding portion around an optical axis of the illumination unit, shifting the light-shielding portion in a predetermined direction perpendicular to the optical axis of the illumination unit, or replacing the light-shielding portion with another light-shielding portion.

10. 2. The imaging device according to claim 1, wherein the illumination area adjustment unit includes a transmission unit that transmits the illumination light so as to shift the optical axis of the illumination unit in a predetermined direction perpendicular to the optical axis of the illumination unit.

11. the illumination unit is disposed at a position optically conjugate with the object and includes a field stop that regulates a beam diameter of the illumination light; The imaging device according to claim 10 , wherein the transmission section is disposed closest to the field stop among the optical elements included in the illumination section.

12. 11. The imaging device according to claim 10, wherein the illumination area adjustment unit adjusts the illumination area by rotating the transmission unit around an axis perpendicular to both the predetermined direction and the optical axis of the illumination unit.

13. The imaging device according to claim 1 , wherein the illumination area adjustment section includes a reflecting section that reflects the illumination light.

14. the illumination unit includes an aperture diaphragm for adjusting an amount of the illumination light, The imaging device according to claim 13 , wherein the reflecting section is disposed closest to the aperture stop among the optical elements included in the illumination section.

15. The imaging device according to claim 13 , wherein the illumination area adjustment section adjusts the illumination area by adjusting an angle of a reflecting surface of the reflecting section.

16. the illumination unit includes a light source that emits the illumination light, and an illumination optical system that guides the illumination light from the light source to the object; 2. The imaging device according to claim 1, wherein the illumination unit is configured to be able to adjust at least one of an incident angle of the illumination light with respect to the object, a numerical aperture of the illumination optical system, a wavelength of the illumination light, an amount of the illumination light, and a polarization of the illumination light.

17. 2. The imaging device according to claim 1, wherein the number of light sources included in the illumination unit that emits the illumination light is one.

18. the object has a predetermined surface including the first region and the second region; 2. The imaging device according to claim 1, wherein an optical axis of the illumination unit is non-perpendicular and non-parallel to the predetermined plane.

19. 20. The imaging device according to claim 18, wherein an optical axis of the imaging section is perpendicular to the predetermined plane.

20. The imaging device according to claim 1, further comprising a control unit that causes the imaging unit to acquire the image in one of the first adjustment and the second adjustment selected based on an input parameter, or causes the imaging unit to acquire the image in each of the first adjustment and the second adjustment.

21. 21. The imaging device according to claim 20, wherein the input parameters include a material of the object.

22. An exposure apparatus that projects an image of a pattern of an original onto a substrate and exposes the substrate, comprising: a projection optical system that guides the exposure light that has passed through the original onto the substrate; An imaging device according to any one of claims 1 to 21, which acquires an image of the substrate on which an alignment mark is formed; a control unit that acquires a position of the alignment mark in a plane perpendicular to the optical axis of the projection optical system from an image of the alignment mark included in the image of the substrate acquired by the imaging device, and adjusts a position of the stage based on the acquired position; An exposure apparatus comprising:

23. exposing a substrate by the exposure apparatus according to claim 22; developing the exposed substrate; A method for producing an article, comprising:

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