Foreign matter inspection device, exposure device, and object manufacturing method

Abstract

To provide a foreign matter inspection device capable of improving the accuracy of foreign matter inspection compared with a conventional manner.SOLUTION: A foreign matter inspection device includes: a projection section for emitting inspection light toward a predetermined area of an object; an imaging section for acquiring an image by receiving light from the predetermined area; and an image processing section for determining whether foreign matter exists in the predetermined area based on an image extracted according to the time of acquisition by the imaging section.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, there has been a demand for improving the accuracy of detecting foreign matter in a foreign matter inspection apparatus that determines whether or not a foreign matter exists in an object. Patent Document 1 discloses a foreign body inspection device that improves the accuracy of foreign body detection by providing a light shielding plate to prevent inspection light from entering unnecessary areas and thereby suppressing the generation of flare light from the unnecessary areas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-62457 Summary of the Invention [Problem to be solved by the invention]

[0004] Even if a light shield is provided to prevent inspection light from entering some unnecessary areas that may generate flare light, as in the foreign body inspection device disclosed in Patent Document 1, the improvement in foreign body detection accuracy will not be sufficient if the inspection light enters other remaining unnecessary areas. SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a foreign matter inspection apparatus capable of improving the accuracy of foreign matter detection as compared with the conventional apparatus. [Means for solving the problem]

[0005] The foreign body inspection device of the present invention is characterized by comprising a light-projecting unit that emits inspection light toward a predetermined area of ​​an object, an imaging unit that obtains an image by receiving light from the predetermined area, and an image processing unit that determines whether a foreign body is present in the predetermined area based on the image extracted according to the time obtained by the imaging unit. Effect of the Invention

[0006] According to the present invention, it is possible to provide a foreign matter inspection device that can improve the foreign matter detection accuracy as compared with the conventional device. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic perspective view of a foreign matter inspection device according to a first embodiment. [Diagram 2] 4 is a flowchart showing a foreign matter inspection process performed by the foreign matter inspection device according to the first embodiment. [Diagram 3] 2 is a diagram showing an arrangement of cells in an object inspected by the foreign matter inspection device according to the first embodiment. [Figure 4] FIG. 2 is a schematic cross-sectional view of a portion of the foreign matter inspection device according to the first embodiment. [Diagram 5] 5A and 5B are diagrams showing changes over time in an image of a predetermined cell of an object acquired by the foreign matter inspection device according to the first embodiment. [Figure 6] FIG. 11 is a schematic perspective view of a foreign matter inspection device according to a second embodiment. [Figure 7] 10 is a flowchart showing a foreign matter inspection process performed by a foreign matter inspection device according to a second embodiment. [Figure 8] FIG. 13 is a schematic perspective view of a foreign matter inspection device according to a third embodiment. [Figure 9] 1 is a schematic cross-sectional view of an exposure apparatus equipped with a foreign substance inspection apparatus according to any one of the first to third embodiments. [Figure 10] FIG. 1 is a schematic cross-sectional view of a conventional foreign matter inspection device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a foreign matter inspection device according to the present embodiment will be described in detail with reference to the accompanying drawings. Note that the drawings shown below may be drawn at a scale different from the actual scale in order to facilitate understanding of the present embodiment. In the following description, two directions perpendicular to each other within a plane in which the object 2 moves as a result of being driven by the drive unit 9 are defined as the X direction and the Y direction, and a direction perpendicular to the plane is defined as the Z direction.

[0009] [First embodiment] FIG. 10 shows a schematic cross-sectional view of a conventional foreign matter inspection device 501.

[0010] As shown in FIG. 10, in a conventional foreign matter inspection device 501 , inspection light is irradiated from a light source unit 503 onto a predetermined area of ​​an object 2 mounted on a mounting part 506 that is moved by a driving part 509 . Next, the reflected light from the predetermined area is received by the image sensor 505 . Then, the image of the specified area of ​​the object 2 acquired by the imaging element 505 is processed by the image processing unit 507 to determine whether or not a foreign object 10 is present in the specified area, and the result of the determination is output by the display unit 508, thereby detecting the foreign object 10.

[0011] Furthermore, in the conventional foreign body inspection device 501, a light shielding plate 511 is provided to suppress irradiation of the inspection light from the light source unit 503 onto each component constituting the mounting portion 506, thereby suppressing the generation of diffuse reflected light by each component. This makes it possible to suppress the formation of flare or ghosts due to the diffusely reflected light in the image of a specified area of ​​the object 2 acquired by the image sensor 505, thereby improving the accuracy of detecting the presence of a foreign object 10 in the specified area.

[0012] In this manner, the conventional foreign matter inspection device 501 uses a hardware configuration to suppress the formation of flare and ghosts in the image of the object 2 acquired by the image sensor 505, thereby improving the accuracy of detecting the presence of a foreign matter 10 in the object 2. Another foreign body inspection apparatus is also known that uses a hardware configuration in which an aperture is used to suppress the formation of flare and ghosts in an image of an object. However, even if a hardware configuration using a light shield or an aperture is used, it is extremely difficult to completely suppress the formation of flare and ghosts caused by diffuse reflection of the inspection light from the light source unit that is generated by objects other than foreign bodies due to diffraction of light.

[0013] On the other hand, foreign matter inspection devices that use software configurations to improve the accuracy of detecting the presence of foreign matter in an object are also known. For example, a foreign body inspection device is known that irradiates an inspection light onto a predetermined area on the surface of an object, receives the light reflected from the predetermined area, and determines whether or not a defect exists in the predetermined area. The foreign body inspection device uses software to remove flare and ghost images that are formed due to diffuse reflection from the back surface, etc.

[0014] However, in foreign substance inspection devices that use such software configurations, the areas in the acquired image where flare or ghosts are formed are calculated in advance using a simulation or the like, and the image is processed to remove the flare or ghosts in those areas. Therefore, only the flare and ghosts in the area calculated in this way are removed.

[0015] As described above, in a foreign substance inspection device using the above-mentioned hardware configuration or a foreign substance inspection device using the above-mentioned software configuration, it is difficult to sufficiently suppress the formation of flare and ghosts in the acquired images. Therefore, an object of this embodiment is to provide a foreign matter inspection apparatus capable of detecting foreign matters with high accuracy by using an image in which the formation of flare and ghosts is sufficiently suppressed.

[0016] FIG. 1 shows a schematic perspective view of a foreign matter inspection device 1 according to the first embodiment. The foreign matter inspection device 1 according to this embodiment includes a light source unit 3, a shutter 4 (light blocking member), an imaging element 5 (imaging section), a mounting section 6, an image processing section 7, a display section 8, a drive section 9, and a control section 20. The light source unit 3 is configured to emit inspection light toward an object 2 that is mounted on a mounting portion 6 and is to be inspected for foreign objects.

[0017] The shutter 4 blocks the inspection light emitted from the light source unit 3 when closed, and has an opening through which the inspection light emitted from the light source unit 3 passes when opened. That is, the shutter 4 is configured to control the irradiation time of the inspection light onto the object 2 by controlling the opening and closing of the shutter 4.

[0018] Further, a diaphragm and a lens (not shown) are provided on the optical path of the inspection light between the shutter 4 and the object 2 for defining the irradiation area (predetermined area) of the object 2 with the inspection light. In the foreign matter inspection device 1 according to this embodiment, the light source unit 3, the shutter 4, the control unit 20, the diaphragm, the lens, and the like form a light projecting unit.

[0019] The imaging element 5 is configured to obtain an image by receiving light from the object 2, including reflected light generated when a foreign object 10 present on the object 2 reflects the incident inspection light. That is, in the foreign matter inspection device 1 according to this embodiment, the light source unit 3 and the image pickup element 5 are arranged on the same side with respect to a predetermined plane of the object 2.

[0020] The image processing unit 7 is configured to process the image of the object 2 acquired by the imaging element 5 to determine whether or not a foreign object is present on the object 2. Specific image processing by the image processing unit 7 will be described later. The display unit 8 is configured to display the result of the image processing by the image processing unit 7, that is, the result of the judgment on the object 2.

[0021] The driving unit 9 is configured to change the area of ​​the object 2 that is irradiated with the inspection light by moving the mounting unit 6 on which the object 2 is mounted, for example, within the XY plane. The control unit 20 is configured to control the driving of the light source unit 3, the shutter 4, and the driving unit 9, for example.

[0022] In the foreign matter inspection device 1 according to this embodiment, inspection light is emitted from the light source unit 3 and the shutter 4 is opened, thereby starting inspection of a predetermined area of ​​the object 2 for foreign matters. Next, the image sensor 5 receives light from the specified area of ​​the object 2, and the image information acquired by the image sensor 5 is processed by the image processing unit 7 to determine whether or not a foreign object is present in the specified area of ​​the object 2, and the results of the image processing by the image processing unit 7 are output to the display unit 8. Then, the mounting part 6 on which the object 2 is mounted is moved within the XY plane by the drive part 9, and the entire specified surface of the object 2 that is parallel to the XY plane is scanned with the inspection light, thereby making it possible to inspect whether or not there are foreign objects on that specified surface of the object 2.

[0023] FIG. 2 is a flowchart showing a foreign matter inspection process by the foreign matter inspection device 1 according to this embodiment. Each step in the flowchart is performed by the control unit 20.

[0024] First, when the foreign body inspection device 1 of this embodiment starts the inspection process for foreign bodies on a predetermined surface of the object 2 parallel to the XY plane, it controls the drive unit 9 so that the inspection light from the light source unit 3 is irradiated to the cell (X0, Y0) on the predetermined surface of the object 2 (step S101). It should be noted that the cell referred to here is an area on a given surface of the object 2 where it is possible to determine whether or not a foreign substance is present in a single inspection, that is, an area corresponding to a light receiving area on the light receiving surface of the imaging element 5.

[0025] FIG. 3 is a diagram showing an arrangement of cells on a predetermined surface parallel to the XY plane of the object 2 inspected by the foreign matter inspection apparatus 1 according to this embodiment. As shown in FIG. 3, in the foreign body inspection apparatus 1 according to this embodiment, m+1 cells are arranged in the X direction and n+1 cells in the Y direction, i.e., (m+1) × (n+1) cells, in a lattice pattern on a predetermined surface of the object 2.

[0026] Next, the light source unit 3 is turned on to emit inspection light (step S102), and the shutter 4 is opened (step S103), whereby the inspection light is emitted onto the cell (X0, Y0) of the object 2. Then, the light from the cell (X0, Y0) of the object 2, including reflected light generated when the inspection light is reflected by the cell (X0, Y0) of the object 2, is received by the imaging element 5, and an image of the cell (X0, Y0) of the object 2 is obtained (step S104).

[0027] Next, the image of the cell (X0, Y0) of the object 2 acquired by the imaging element 5 in step S104 is transmitted to the image processing unit 7 (step S105). Then, assuming that the time T when the shutter 4 is opened in step S103 is 0, it is determined whether the time T is less than T3 (step S106). It should be noted that the time T3 used in step S106 is set to be sufficiently longer than the time T2 described below.

[0028] If the time T is less than T3 (Yes in step S106), the process returns to step S104, and acquisition of the image of the cell (X0, Y0) of the object 2 continues. On the other hand, if the time T is equal to or greater than T3 (No in step S106), the shutter 4 is closed (step S107) to terminate irradiation of the inspection light onto the cell (X0, Y0) of the object 2.

[0029] Next, as described in detail below, the images of the cells (X0, Y0) of the multiple objects 2 received by the image processing unit 7 in step S105 are processed to determine whether a foreign object is present in the cell (X0, Y0) of the object 2 (step S108). Then, the result of the determination made by the image processing unit 7 in step S108 is output by the display unit 8 (step S109).

[0030] Next, it is determined whether the Y coordinate of the cell currently being checked is Yn (step S110). If the Y coordinate of the cell currently being inspected is not Yn (No in step S110), the mounting unit 6 is moved by the drive unit 9 so that the adjacent cell in the Y direction, in this case cell (X0, Y1), is inspected (step S111). Then, the process returns to step S103, and a test is performed on cell (X0, Y1).

[0031] On the other hand, if the Y coordinate of the cell currently being inspected is Yn (Yes in step S110), the mounting unit 6 is moved by the drive unit 9 so that the cell whose Y coordinate is Y0, in this case cell (X0, Y0), is inspected without changing the X coordinate (step S112). Next, in step S112, the mounting unit 6 is moved by the driving unit 9 to determine whether the X coordinate of the cell to be inspected is Xm (step S113).

[0032] If the X coordinate of the cell to be inspected is not Xm (No in step S113), the mounting unit 6 is moved by the driving unit 9 so that the adjacent cell in the X direction, that is, in this case, cell (X1, Y0), is inspected (step S114). Then, the process returns to step S103, and a test is performed on the cell (X1, Y0).

[0033] On the other hand, if the X coordinate of the cell to be inspected is Xm (Yes in step S113), inspection has been performed on all of the (m+1) × (n+1) cells from (X0, Y0) to (Xm, Yn), and the inspection process for foreign bodies on the specified surface of the object 2 is terminated.

[0034] FIG. 4 is a schematic cross-sectional view of a portion of the foreign matter inspection device 1 according to this embodiment. Specifically, Figure 4 shows inspection light from light source unit 3 being irradiated onto a specific cell on a specific surface of object 2, and if a foreign object 10 is present on the specific cell, light from the specific cell containing foreign object 10 is received by image sensor 5.

[0035] FIG. 4 also shows how inspection light from the light source unit 3 is irradiated onto a predetermined portion of the mounting portion 6, and how the light from the predetermined portion is received by the imaging element 5. That is, in the foreign body inspection device 1 according to this embodiment, it is required to distinguish between the light reflected by the foreign body 10 received by the imaging element 5 and the diffusely reflected light by objects other than the foreign body 10, such as a predetermined portion of the mounting part 6.

[0036] Therefore, in the foreign body inspection device 1 of this embodiment, in order to distinguish between reflected light by the foreign body 10 and diffusely reflected light by an object other than the foreign body 10, such as a specific portion of the mounting part 6, the difference between the time at which the reflected light and the diffusely reflected light are received by the image sensor 5 is utilized. Specifically, as shown in FIG. 4, consider a total optical path a (second total optical path) indicated by solid arrows of the inspection light between the light source unit 3 and the foreign object 10, and the light reflected by the foreign object 10 between the foreign object 10 and the imaging element 5.

[0037] Also, consider a total optical path b (first total optical path) indicated by the dashed arrow of the inspection light between the light source unit 3 and a specified portion of the mounting portion 6, and the diffusely reflected light by the specified portion between the specified portion and the imaging element 5. At this time, in the foreign body inspection device 1 of this embodiment, the mounting unit 6 is positioned by the driving unit 9 so that the inspection light is irradiated to a specific cell on a specific surface of the object 2 on which the foreign body 10 is present, so it is considered that the distance of the total optical path a is shorter than the distance of the total optical path b. In addition, if a specific portion of the mounting portion 6 onto which the inspection light is irradiated has a concave shape, the diffuse reflected light generated in the concave is thought to be multiple-reflected, making the total optical path b of the diffuse reflected light even longer.

[0038] Therefore, a difference occurs between the time when the imaging element 5 receives the reflected light from the foreign object 10 that has traveled the total optical path a and the time when the imaging element 5 receives the diffusely reflected light from a specified part of the mounting portion 6 that has traveled the total optical path b. Therefore, in the foreign matter inspection device 1 according to this embodiment, as explained above using the flowchart shown in FIG. 2, in steps S104 to S106, acquisition of images of a specified cell on a specified surface of the object 2 is repeated until time T3.

[0039] In this case, it is necessary to repeatedly acquire images of a specific cell of the object 2 at intervals of a time shorter than the time it takes for light to travel the distance difference ba between the total optical path distance a and the total optical path distance b. For example, the foreign body inspection device 1 according to this embodiment can repeatedly acquire images of a predetermined cell of the object 2 at time intervals (resolution) of 500 picoseconds or less, preferably 300 picoseconds or less, and more preferably 100 picoseconds or less.

[0040] For example, if images of a given cell of object 2 are repeatedly acquired at time intervals of 100 picoseconds, the speed of light is 3 × 10 8 m / sec, the distance difference ba is (3×10 8 m / s)×(100×10 -12 If the reflected light from the foreign object 10 is greater than or equal to 30 mm, the reflected light from the foreign object 10 can be identified. Conversely, when the distance difference ba is sufficiently greater than 30 mm, a resolution of 100 picoseconds is not necessary.

[0041] FIG. 5 shows the time change of an image of a predetermined cell in which a foreign substance 10 exists on a predetermined surface of an object 2, the image being acquired by the foreign substance inspection device 1 according to this embodiment. Specifically, FIG. 5 shows an axis of time T, events at each time, and images captured at each time.

[0042] First, the light source unit 3 emits the inspection light at a time sufficiently before time 0 (first time) at which the shutter 4 is opened. Then, at time 0, the shutter 4 is opened, and the image sensor 5 starts acquiring an image of a predetermined cell on a predetermined surface of the object 2 .

[0043] Next, at a predetermined time T1 (third time) after time 0, i.e., a time after time T1 which is calculated as a time after time 0 by the time it takes for light to travel along the total optical path a, the image sensor 5 captures an image of the specified cell in which the foreign object 10 is present. When the object 2 transmits the irradiated inspection light, a predetermined brightness is measured in a predetermined area by receiving only the light reflected by the foreign object 10 present in the specified cell in the image acquired by the imaging element 5 as shown in Figure 5. Then, images of the specific cell in which the foreign substance 10 exists are repeatedly captured by the imaging element 5 from time T1 onwards.

[0044] Next, at a predetermined time T2 (second time) after time T1, i.e., a time after time T2 which is calculated as a time after time 0 by the time it takes for light to travel along the total optical path b described above, diffusely reflected light from an object other than foreign matter 10 is received by image sensor 5. In FIG. 5, a predetermined portion of the mounting portion 6 is shown as the object other than the foreign object 10.

[0045] As a result, flare or ghosting is caused by the diffusely reflected light on the image of a predetermined cell of the object 2 captured by the imaging element 5. Then, at a predetermined time T3 after time T2, the image capturing element 5 finishes capturing images of the predetermined cell on the predetermined surface of the object 2. As a result, a total of (N+1) images of the predetermined cell, d0 to dN, are captured.

[0046] As shown in FIG. 5, between time 0 and time T1, light from a specific cell on a specific surface of the object 2 does not reach the image sensor 5, and therefore black images d0 and d1, which do not receive any light, are acquired. Next, between time T1 and time T2, light from the specific cell in which the foreign substance 10 exists reaches the imaging element 5, and images d2 to d4 of the specific cell are acquired.

[0047] Between time T2 and time T3, diffusely reflected light from objects other than the foreign substance 10 also reaches the image sensor 5, and images d5 to dN of the specified cell in which flare or ghost is formed due to the diffusely reflected light are acquired. That is, in the foreign body inspection device 1 of this embodiment, a total of three types of images are acquired, including an image in which no light is received, an image of a specific cell in which a foreign body 10 exists, and an image of the specific cell in which a flare or ghost is formed.

[0048] It should be noted that time T3 here should be determined to be a time sufficiently later than time T2, and time T2 can be obtained by calculating the total optical path b for objects other than the foreign substance 10 that is thought to cause the above-mentioned flare or ghost, and then obtaining time T2 from the calculated total optical path b. In the foreign body inspection device 1 of this embodiment, when determining whether a foreign body 10 is present in a specified cell of the object 2 by processing the multiple images d0 to dN received by the image processing unit 7, images d5 to dN acquired at times after time T2 are excluded. In other words, in the foreign body inspection device 1 of this embodiment, when determining whether a foreign body 10 is present in a specified cell of the object 2 by processing multiple images d0 to dN received by the image processing unit 7, images d0 to d4 acquired at a time prior to time T2 are extracted.

[0049] That is, the image processing unit 7 judges whether or not a foreign substance 10 exists in a predetermined cell of the object 2 based on the extracted images d0 to d4. At this time, for example, when a portion having a brightness equal to or greater than a predetermined threshold is measured in the acquired images d0 to d4, it can be determined that a foreign substance 10 exists in the object 2 in that predetermined cell.

[0050] In other words, as shown in FIG. 5, it is possible to determine that a foreign substance 10 exists in a predetermined cell of the object 2 based on the magnitude of brightness in a predetermined portion of the images d2 to d4 among the images d0 to d4. Then, when it is determined that the foreign matter 10 is present in the predetermined cell of the object 2, cleaning may be performed to remove the foreign matter 10 from the object 2 using, for example, a cleaning device (foreign matter removal device) not shown.

[0051] The presence of the foreign matter 10 in a predetermined cell of the object 2 may be determined based on the size of the area of ​​a portion having a brightness equal to or greater than a predetermined threshold value in the acquired image. Furthermore, if it is determined that the foreign matter 10 present in a specified cell of the object 2 is sufficiently small based on the area size of the part in the acquired image that has a brightness equal to or greater than a specified threshold value, control can be performed so that cleaning is not performed.

[0052] As described above, in the foreign matter inspection device 1 according to this embodiment, the image processing unit 7 determines whether a foreign matter 10 is present in a predetermined cell of the object 2 based on an image extracted according to the time acquired by the imaging element 5. This makes it possible to accurately determine whether or not the foreign matter 10 is present in the object 2 by using an image in which the formation of flare and ghosts due to diffusely reflected light generated by objects other than the foreign matter 10 is sufficiently suppressed.

[0053] The foreign matter inspection apparatus 1 of this embodiment can be used, for example, when determining whether a foreign matter 10 is present on an original used in an exposure apparatus as the object 2, but it can also be used to determine whether a foreign matter 10 is present on a substrate used in the exposure apparatus. Furthermore, the foreign matter inspection apparatus 1 of this embodiment can determine whether foreign matter 10 is present in various objects, such as an original chuck for holding an original on an original stage provided in an exposure apparatus, and a substrate chuck for holding a substrate on a substrate stage.

[0054] Furthermore, the foreign matter inspection device 1 according to this embodiment is not limited to an object 2 that transmits inspection light, and may also perform inspection to determine the presence of foreign matter on an object 2 that reflects inspection light. Furthermore, the foreign matter inspection device 1 according to this embodiment is not limited to inspection for determining whether or not the foreign matter 10 is present in the object 2, but can also be used for other inspections of the object 2 using the light projecting unit and the light receiving unit.

[0055] Furthermore, in the foreign body inspection device 1 according to this embodiment, a plurality of images are acquired by repeatedly capturing images of a specific cell of the object 2, and it is determined whether a foreign body 10 is present in the specific cell of the object 2 based on an image extracted from the plurality of acquired images according to the time of acquisition. However, if it is possible to determine the time T2 at which the formation of flare or ghosts due to diffuse reflection of light from objects other than the foreign object 10 begins in an image of a specific cell of the object 2, it is possible to determine whether the foreign object 10 is present based on a single image of that cell acquired at a time prior to time T2.

[0056] [Second embodiment] FIG. 6 shows a schematic perspective view of a foreign substance inspection device 101 according to the second embodiment. The foreign body inspection device 101 according to this embodiment has the same configuration as the foreign body inspection device 1 according to the first embodiment, except that a light source unit 103, a shutter 104, and an image sensor unit 105 are provided instead of the light source unit 3, the shutter 4, and the image sensor 5. Therefore, the same members are given the same reference numerals, and descriptions thereof will be omitted.

[0057] Specifically, the light source unit 103 provided in the foreign substance inspection apparatus 101 according to this embodiment is, for example, (m+1) light sources 103 arranged along the X direction. 0 , 103 1 , , 103 m It has. and multiple light sources 103 0 ~103 mare each positioned so as to irradiate inspection light to (m+1) cells (X0,Y), (X1,Y), ..., (Xm,Y) (multiple regions) arranged along the X direction at a predetermined Y coordinate Y on a predetermined surface of object 2.

[0058] The image sensor unit 105 provided in the foreign body inspection apparatus 101 according to this embodiment includes (m+1) image sensors 105 arranged along the X direction, for example. 0 , 105 1 , , 105 m It has. and a plurality of image sensors 105 0 ~105 m are each positioned to receive light from (m+1) cells (X0,Y), (X1,Y), ..., (Xm,Y) arranged along the X direction at a predetermined Y coordinate Y on a predetermined surface of object 2.

[0059] FIG. 7 is a flowchart showing a foreign matter inspection process by the foreign matter inspection apparatus 101 according to this embodiment. Each step in the flowchart is performed by the control unit 20.

[0060] First, when the inspection process for foreign bodies on a predetermined surface of the object 2 parallel to the XY plane begins, the driving unit 9 is controlled so that the inspection light from the light source unit 103 is irradiated to each of the cells (X0, Y0) to (Xm, Y0) on the predetermined surface of the object 2 (step S201). Next, the light source unit 103 is turned on to emit inspection light (step S202), and the shutter 4 is opened (step S203), whereby the inspection light is emitted onto each of the cells (X0, Y0) to (Xm, Y0) of the object 2. Then, light from each of the cells (X0, Y0) to (Xm, Y0) of the object 2, including reflected light generated by the inspection light being reflected by each of the cells (X0, Y0) to (Xm, Y0) of the object 2, is received by the image sensor unit 105 (step S204).

[0061] Next, the image acquired by the image sensor unit 105 in step S204 is transmitted to the image processing unit 7 (step S205). Then, assuming that the time when the shutter 4 is opened in step S203 is T=0, it is determined whether the time T is less than T3 (step S206). Incidentally, the time T3 used in step S206 is set to be sufficiently longer than the time T2, similarly to the first embodiment.

[0062] If the time T is less than T3 (Yes in step S206), the process returns to step S204, and the acquisition of images of the object 2 from the cells (X0, Y0) to (Xm, Y0) continues. On the other hand, if the time T is equal to or greater than T3 (No in step S206), the shutter 104 is closed (step S207) to terminate irradiation of the inspection light onto the cells (X0, Y0) to (Xm, Y0) of the object 2.

[0063] Next, similarly to the first embodiment, the multiple images received by the image processing unit 7 in step S205 are processed to determine whether or not a foreign object is present in each of the cells (X0, Y0) to (Xm, Y0) of the object 2 (step S208). Then, the result of the determination made by the image processing unit 7 in step S208 is output by the display unit 8 (step S209).

[0064] Next, it is determined whether the Y coordinate of the cell currently being checked is Yn (step S210). If the Y coordinate of the cell currently being inspected is not Yn (No in step S210), the mounting unit 6 is moved by the drive unit 9 so that the adjacent cells in the Y direction, i.e., in this case cells (X0, Y1) to (Xm, Y1), are inspected (step S211). Then, the process returns to step S203, and the cells (X0, Y1) through (Xm, Y1) are inspected.

[0065] On the other hand, if the Y coordinate of the cell currently being inspected is Yn (Yes in step S210), inspection has been completed for all (m+1) × (n+1) cells from (X0, Y0) to (Xm, Yn), and the inspection process for foreign bodies in object 2 is terminated.

[0066] As described above, in the foreign matter inspection apparatus 101 according to this embodiment, the imaging elements 105 of the imaging element unit 105 0 ~105 m It is determined whether or not a foreign object 10 exists in each of the plurality of cells of the object 2 based on the images extracted according to the time when each was acquired. This makes it possible to accurately determine whether or not the foreign matter 10 is present in the object 2 by using an image in which the formation of flare and ghosts due to diffusely reflected light generated by objects other than the foreign matter 10 is sufficiently suppressed.

[0067] Furthermore, in the foreign matter inspection apparatus 101 according to this embodiment, the number of cells of the object 2 that can be inspected at one time can be increased compared to the foreign matter inspection apparatus 1 according to the first embodiment. Therefore, the time required to perform an inspection to determine whether or not the foreign substance 10 exists on a predetermined surface of the object 2 can be shortened, that is, the throughput can be increased.

[0068] [Third embodiment] FIG. 8 shows a schematic perspective view of a foreign matter inspection device 201 according to the third embodiment. The foreign matter inspection device 201 according to this embodiment has the same configuration as the foreign matter inspection device 101 according to the second embodiment, except that an image sensor unit 205 is provided instead of the image sensor unit 105. Therefore, the same members are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0069] Specifically, the image sensor unit 205 provided in the foreign substance inspection device 201 according to this embodiment is made up of (m+1) image sensors 205 arranged along the X direction, for example. 0 , 205 1 , , 205 m It has. and a plurality of image sensors 205 0 ~205 m are each positioned to receive light from (m+1) cells (X0,Y), (X1,Y), ..., (Xm,Y) arranged along the X direction at a predetermined Y coordinate Y on a predetermined surface of object 2.

[0070] The imaging element unit 205 also includes a plurality of imaging elements 205 0 , 205 1 , , 205 m are each formed of a Single Photon Avalanche Diode (hereinafter referred to as SPAD) imaging element. A CMOS (Complementary Metal Oxide Semiconductor) image sensor, which is a typical image sensor, measures the amount of light accumulated in a specific pixel within a specific period of time when acquiring light received at the specific pixel as an electrical signal.

[0071] On the other hand, in a SPAD imaging element, when photons are input to a specific pixel and converted into an electric charge, the electric charge is amplified by avalanche amplification, making it possible to count the number of photons. Furthermore, compared to conventional imaging elements such as CMOS imaging elements, the SPAD imaging element can detect light with a small amount of light, and therefore can reduce the amount of inspection light irradiated by the light source unit 103 in the foreign body inspection device 201 of this embodiment.

[0072] In addition, SPAD image sensors are less susceptible to noise even in low-illumination conditions, enabling them to measure the amount of light with high sensitivity and precision. A SPAD imager may also have a time resolution of, for example, about 100 picoseconds.

[0073] In addition, in the foreign matter inspection device 201 according to this embodiment, for example, each member forming the mounting portion 6 is subjected to a black chemical treatment. This allows the reflectance of each member constituting the mounting portion 6 with respect to the inspection light irradiated from the light source unit 103 to be reduced to 4 to 6%.

[0074] Therefore, the generation of diffusely reflected light by objects other than the foreign object 10, and therefore the formation of flare or ghosts due to the diffusely reflected light on the image of each cell of the object 2 acquired by the image sensor unit 205, can be suppressed. In the foreign matter inspection device 201 of this embodiment, the amount of inspection light from the light source unit 103 is reduced as described above, and the generation of diffuse reflected light is suppressed in accordance with the black chemical treatment, thereby making it possible to sufficiently suppress the formation of flare and ghosts on the image of each cell of the object 2.

[0075] In the foreign matter inspection apparatus 201 according to this embodiment, like the foreign matter inspection apparatus 101 according to the second embodiment, it is possible to determine whether a foreign matter 10 is present on a specified surface of the object 2 by following the flowchart shown in FIG. 7.

[0076] As described above, in the foreign matter inspection apparatus 201 according to this embodiment, the plurality of image pickup elements 205 of the image pickup element unit 205 0 ~205 m It is determined whether or not a foreign object 10 exists in each of the plurality of cells of the object 2 based on the images extracted according to the time when each was acquired. In addition, in the foreign matter inspection device 201 according to this embodiment, the amount of inspection light irradiated by the light source unit 103 is reduced by using a SPAD imaging element, and a black chemical treatment is applied to components that may generate diffusely reflected light. This allows the use of an image in which the formation of flare and ghosts caused by diffusely reflected light generated by objects other than the foreign object 10 is sufficiently suppressed, and by suppressing the formation of the flare and ghosts, it is possible to determine with sufficient accuracy whether or not the foreign object 10 is present in the object 2.

[0077] In the foreign matter inspection device 201 according to this embodiment, each member constituting the mounting portion 6 is subjected to a black chemical treatment, but the present invention is not limited to this. In other words, the effects of this embodiment can be enjoyed even if at least a portion of an object that is likely to generate diffusely reflected light that creates flare or ghosts in the image acquired by the image sensor unit 205 has been subjected to a black chemical treatment.

[0078] [Exposure equipment] FIG. 9 shows a schematic cross-sectional view of an exposure apparatus 90 equipped with a foreign substance inspection apparatus 1 according to any one of the first to third embodiments.

[0079] The exposure apparatus 90 includes an illumination optical system 91 , an original stage 93 , a projection optical system 94 , a substrate stage 96 , and an original exchange unit 97 . The illumination optical system 91 is configured to illuminate an original 92 on which a pattern is drawn by irradiating it with exposure light.

[0080] The original stage 93 is configured to hold the original 92 and to drive it in rotational directions about axes parallel to the X-, Y-, and Z-directions. The projection optical system 94 is disposed between the original stage 93 and the substrate stage 96, and is configured to project an image of the pattern formed on the original 92 onto the substrate 95 by guiding the exposure light that has passed through the original 92 onto the substrate 95.

[0081] The substrate stage 96 is configured to hold a substrate 95 to be exposed, and to drive it in the X-direction, Y-direction, and Z-direction, and in rotational directions about axes parallel to the Z-direction. With the above-described configuration, the exposure apparatus 90 can project an image of the pattern of the original 92 onto the substrate 95 and expose the substrate 95 to light.

[0082] The master replacement unit 97 is configured to store a plurality of masters 92 and to replace the master 92 held by the master stage 93 in accordance with a command from a control unit (not shown). The original plate replacement unit 97 also has a foreign matter inspection device 1 relating to any of the first to third embodiments that determines whether a foreign matter is present on the original plate 92, and a foreign matter removal device 98 that removes the foreign matter by cleaning the original plate 92 when it is determined that the foreign matter is present on the original plate 92. In addition, the foreign matter removal device 98 may remove the foreign matter by cleaning the original 92 when it is determined that a foreign matter of a predetermined size or larger is present on the original 92 because the size of an area having a predetermined brightness in the image acquired by the foreign matter inspection device 1 is equal to or larger than a predetermined threshold value.

[0083] [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 90 equipped with a foreign matter inspection apparatus 1 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.

[0084] The method for manufacturing an article according to this embodiment also includes a step of developing the exposed substrate (photosensitive agent) and other known steps of processing the developed substrate. The other well-known processes include etching, photoresist peeling, dicing, bonding, packaging, and the like.

[0085] According to the method for manufacturing an article according to this embodiment, it is possible to manufacture an article of higher quality than before.

[0086] 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.

[0087] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) A foreign body inspection device comprising a light-projecting unit that emits inspection light toward a predetermined area of ​​an object, an imaging unit that acquires an image by receiving light from the predetermined area, and an image processing unit that determines whether a foreign body is present in the predetermined area based on the image extracted according to the time acquired by the imaging unit. (Configuration 2) The foreign body inspection device according to configuration 1, wherein the image processing unit extracts an image acquired at a time after a first time when the light projecting unit starts emitting inspection light from the image acquired by the imaging unit. (Configuration 3) A foreign body inspection device according to configuration 2, wherein the light-projecting unit has a light-shielding member having an opening formed therein that blocks the inspection light when closed, and the image processing unit determines the first time as the time when the opening is opened. (Configuration 4) The foreign body inspection device according to configuration 2 or 3, wherein the image processing unit extracts an image acquired before a second time that is later than the first time from the image acquired by the imaging unit. (Configuration 5) A foreign body inspection device according to configuration 4, further comprising a mounting section on which an object is mounted, and an image processing section calculates a first total optical path distance between the light projecting section and a specified portion of the mounting section, and between the specified portion and the imaging section, and calculates a second time as a time that is later than the first time by the time it takes for light to travel the calculated first total optical path distance. (Configuration 6) A foreign body inspection device according to any one of configurations 2 to 5, characterized in that the image processing unit extracts an image acquired after a third time that is later than the first time from the image acquired by the imaging unit. (Configuration 7) A foreign body inspection device according to configuration 6, characterized in that the image processing unit calculates a second total optical path distance between the light projection unit and the specified area, and between the specified area and the imaging unit, and calculates a third time as a time that is later than the first time by the time it takes for light to travel the calculated second total optical path distance. (Configuration 8) The foreign body inspection device according to any one of configurations 1 to 7, wherein the imaging unit repeatedly acquires images at predetermined time intervals. (Configuration 9) The foreign body inspection apparatus according to configuration 8, wherein the predetermined time interval is 500 picoseconds or less. (Configuration 10) A foreign body inspection device as described in any one of configurations 1 to 9, characterized in that it comprises a mounting unit on which an object is mounted, and a drive unit that moves the mounting unit so as to change the specified area onto which the inspection light is irradiated. (Configuration 11) A foreign body inspection device described in any one of configurations 1 to 10, characterized in that the light-projecting unit has a plurality of light sources that irradiate inspection light onto each of a plurality of areas arranged along a predetermined direction on a predetermined surface of the object, and the imaging unit has a plurality of imaging elements that obtain an image by receiving light from each of the plurality of areas. (Configuration 12) The foreign body inspection device according to any one of configurations 1 to 11, wherein the imaging section has a SPAD imaging element. (Configuration 13) A foreign body inspection device according to any one of configurations 1 to 12, characterized in that the light projecting unit and the imaging unit are arranged on the same side of a predetermined plane including a predetermined area. (Configuration 14) A foreign body inspection device according to any one of configurations 1 to 13, wherein the object transmits the irradiated inspection light. (Configuration 15) A foreign body inspection device according to any one of configurations 1 to 14, comprising a mounting section on which an object is mounted, at least a portion of the mounting section being subjected to a black chemical treatment. (Configuration 16) A foreign body inspection device according to any one of configurations 1 to 15, characterized in that the image processing unit determines whether a foreign body is present in a predetermined area of ​​the object based on the magnitude of luminance in the predetermined area within the image. (Configuration 17) A foreign body inspection device according to any one of configurations 1 to 16, characterized in that the image processing unit determines whether a foreign body is present in a predetermined area of ​​the object based on the size of an area having a predetermined brightness in the image. (Configuration 18) The foreign matter inspection device according to any one of configurations 1 to 17, further comprising a display unit that displays the result of the image processing unit's determination of the presence of a foreign matter in a predetermined area. (Configuration 19) An exposure apparatus that projects an image of a pattern of an original onto a substrate and exposes the substrate, characterized in that it is equipped with a foreign matter inspection apparatus described in any one of Configurations 1 to 18 that determines whether a foreign matter is present on the original. (Configuration 20) An exposure apparatus according to configuration 19, further comprising a foreign matter removal device that removes foreign matter from the original when the foreign matter inspection device determines that foreign matter is present on the original. (Method 1) A method for manufacturing an article, comprising the steps of exposing a substrate by the exposure apparatus according to Configuration 19 or 20, and developing the exposed substrate. [Explanation of symbols]

[0088] 1 Foreign body inspection equipment 2 objects 3 Light source unit (light projector) 4 Shutter (light projector) 5. Imaging element (imaging section) 7 Image Processing Section 10 Foreign object

Claims

1. a light projection unit that projects inspection light toward a predetermined area of ​​the object; an imaging unit that acquires an image by receiving light from the predetermined area; an image processing unit that determines whether a foreign object is present in the predetermined area based on the image extracted according to the time acquired by the imaging unit; A foreign body inspection device comprising:

2. 2. The foreign body inspection device according to claim 1, wherein the image processing unit extracts the image acquired at a time after a first time at which the light projector starts emitting the inspection light from the image acquired by the imaging unit.

3. the light projecting unit has a light blocking member having an opening that blocks the inspection light when closed; 3. The foreign matter inspection apparatus according to claim 2, wherein the image processing section determines the first time as a time when the opening is opened.

4. 3. The foreign body inspection device according to claim 2, wherein the image processing unit extracts the image acquired before a second time that is later than the first time from the image acquired by the imaging unit.

5. A mounting portion on which the object is mounted is provided, The image processing unit includes: Calculating a distance of a first total optical path between the light projecting unit and a predetermined portion of the mounting unit and between the predetermined portion and the imaging unit; 5. The foreign body inspection apparatus according to claim 4, wherein the second time is calculated as a time that is later than the first time by the time it takes for light to travel the calculated first total optical path distance.

6. 3. The foreign body inspection device according to claim 2, wherein the image processing unit extracts the image acquired after a third time that is later than the first time from the image acquired by the imaging unit.

7. The image processing unit includes: Calculating a distance of a second total optical path between the light projecting unit and the predetermined area and between the predetermined area and the imaging unit; 7. The foreign body inspection apparatus according to claim 6, wherein the third time is calculated as a time that is later than the first time by the time it takes for light to travel the calculated second total optical path distance.

8. 2. The foreign matter inspection device according to claim 1, wherein the imaging unit repeatedly acquires the images at predetermined time intervals.

9. 9. The foreign matter inspection apparatus according to claim 8, wherein the predetermined time interval is 500 picoseconds or less.

10. a mounting portion on which the object is mounted; a driving unit that moves the mounting unit so as to change the predetermined area onto which the inspection light is irradiated; 2. The foreign matter inspection apparatus according to claim 1, further comprising:

11. the light projecting unit has a plurality of light sources that irradiate the inspection light onto a plurality of regions that are arranged along a predetermined direction on a predetermined surface of the object, 2. The foreign body inspection device according to claim 1, wherein the imaging section includes a plurality of imaging elements that obtain the image by receiving light from each of the plurality of regions.

12. 2. The foreign matter inspection device according to claim 1, wherein the imaging unit has a SPAD imaging element.

13. 2. The foreign body inspection device according to claim 1, wherein the light projecting section and the imaging section are disposed on the same side of a predetermined plane including the predetermined area.

14. 2. The foreign matter inspection apparatus according to claim 1, wherein the object transmits the irradiated inspection light.

15. A mounting portion on which the object is mounted is provided, 2. The foreign matter inspection device according to claim 1, wherein at least a part of the mounting portion is subjected to a black chemical treatment.

16. 2. The foreign matter inspection apparatus according to claim 1, wherein the image processing section determines whether the foreign matter is present in a predetermined area of ​​the object based on a luminance level in the predetermined area within the image.

17. 2. The foreign matter inspection device according to claim 1, wherein the image processing section determines whether the foreign matter is present in the predetermined area of ​​the object based on the size of an area having a predetermined brightness in the image.

18. 2. The foreign matter inspection apparatus according to claim 1, further comprising a display unit that displays a result of the image processing unit's determination of the presence of the foreign matter in the predetermined region.

19. An exposure apparatus that projects an image of a pattern of an original onto a substrate and exposes the substrate, comprising:

19. An exposure apparatus comprising: the foreign matter inspection apparatus according to claim 1, which judges whether a foreign matter is present on the original.

20. 20. An exposure apparatus according to claim 19, further comprising a foreign matter removal device that removes foreign matter from the original when the foreign matter inspection device determines that a foreign matter is present on the original.

21. exposing a substrate by the exposure apparatus according to claim 19; developing the exposed substrate; A method for producing an article, comprising:

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