Image processing device and image processing method

Abstract

This image processing device (2) according to the present disclosure comprises: a support unit (40) that rotatably supports an object around a rotation axis (C1); an objective lens (21) that condenses a reflected light (R1) reflected by the object; drive units (12, 22) that can change a Z position, which is the relative position of the objective lens (21) with respect to the object, in an optical axis (C2) direction of the objective lens (21); an acquisition unit (31) that acquires a captured image of the object via the objective lens (21); a control unit (35) that causes the acquisition unit (31) to acquire a plurality of captured images; a specification unit (32) that specifies, in a plurality of captured images having different Z positions and different rotation angles (theta) of the object, a pixel position that is the position of a pixel having a luminance greater than or equal to a prescribed luminance; a storage unit (33) that stores the specified pixel position (P) as high-luminance time information together with the Z position and the rotation angle (theta) in each captured image; and a generation unit (34) that generates image information of the object on the basis of the high-luminance time information.

Description

Image processing device and image processing method

[0001] The present disclosure relates to an image processing device and an image processing method.

[0002] For example, Patent Document 1 proposes a method for measuring the shape of the circumference of a wafer edge.

[0003] Patent No. 6644282

[0004] Thus, there is a demand for a method for measuring information about an object, such as the shape of the circumference of a wafer edge, quickly and accurately.

[0005] The present disclosure has been made to solve such problems, and aims to provide an image processing device and an image processing method that can measure information about an object quickly and accurately.

[0006] The image processing device according to the present disclosure includes a support unit that supports an object rotatably around a rotation axis, an objective lens that focuses light reflected by the object, a drive unit that can change a Z position, which is the relative position between the object and the focusing position of the objective lens in the optical axis direction of the objective lens, an acquisition unit that acquires an image of the object via the objective lens, a control unit that controls the support unit and the drive unit and causes the acquisition unit to acquire a plurality of the imaged images, an identification unit that identifies pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of the imaged images, each of which has a different Z position and a different rotation angle of the object, a memory unit that stores the identified pixel positions together with the Z position and the rotation angle in each imaged image as high brightness information, and a generation unit that generates image information of the object based on the stored plurality of high brightness information.

[0007] In the image processing device, the control unit may cause the acquisition unit to acquire multiple captured images of the end of the object by rotating the object around the rotation axis using the support unit while changing the Z position using the drive unit.

[0008] In the image processing device, the driving unit can change the radial position, which is the relative position between the object and the focusing position of the objective lens, in a direction perpendicular to the rotation axis, and the control unit can rotate the object around the rotation axis using the support unit, change the radial position using the driving unit in a first direction perpendicular to the rotation axis, and keep the Z position constant at the first position, and cause the acquisition unit to acquire multiple captured images of the main surface of the object.

[0009] In the image processing device, the control unit rotates the object around the rotation axis using the support unit, changes the radial position in a second direction opposite to the first direction using the drive unit, and keeps the Z position constant at the second position, causing the acquisition unit to acquire multiple images of the main surface of the object, wherein the second position is different from the first position, and the difference between the second position and the first position may be within the focal depth of an optical system including the objective lens.

[0010] The image processing device according to the present disclosure includes a support unit that supports an object rotatably around a rotation axis, an objective lens that focuses light reflected by the object, a drive unit that can change the Z position, which is the relative position between the object and the focusing position of the objective lens in the optical axis direction of the objective lens, an acquisition unit that acquires an image of the object through the objective lens, a control unit that controls the support unit and the drive unit and causes the acquisition unit to acquire multiple images, an identification unit that identifies pixel positions where the brightness is greater than or equal to a predetermined value in multiple images that have different Z positions and different rotation angles of the object, and a generation unit that generates image information of the object based on the pixels where the brightness is greater than or equal to the predetermined value, and the generation unit may generate image information of the object at the specific rotation angle based on pixels where the brightness is greater than or equal to the predetermined value in multiple images that have different Z positions and that have the rotation angle at a specific rotation angle.

[0011] In the image processing device, the generation unit may generate the image information of the object at a plurality of specific rotation angles based on pixels that have a brightness greater than or equal to a predetermined value in a plurality of captured images in which the rotation angle is a first rotation angle and the Z positions are different from each other, and pixels that have a brightness greater than or equal to a predetermined value in a plurality of captured images in which the rotation angle is a second rotation angle and the Z positions are different from each other.

[0012] In the image processing device, the drive unit may be capable of changing an optical axis angle, which is the angle of the optical axis of the objective lens with respect to a plane perpendicular to the rotation axis, and the identification unit may identify pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of the captured images, each of which has a different Z position, rotation angle, and optical axis angle, and the generation unit may generate the image information of the end of the object at the specific rotation angle based on pixels where the brightness is equal to or greater than a predetermined value in a plurality of the captured images, each of which has a rotation angle that is a specific rotation angle, a first optical axis angle, and a different Z position, and pixels where the brightness is equal to or greater than a predetermined value in a plurality of the captured images, each of which has a rotation angle that is a specific rotation angle, a second optical axis angle, and a different Z position.

[0013] In the image processing device, the acquisition unit may acquire a first captured image from a first light receiving unit that receives light of a first wavelength corresponding to a first color in the reflected light, and acquire a second captured image from a second light receiving unit that receives light of a second wavelength corresponding to a second color in the reflected light, the identification unit may identify first-wavelength pixel positions that are the pixel positions where the brightness is equal to or greater than a predetermined value in a plurality of the first captured images that have different Z positions, and identify second-wavelength pixel positions that are the pixel positions where the brightness is equal to or greater than a predetermined value in a plurality of the second captured images that have different Z positions, and the generation unit may generate a color image of the object represented in a plurality of colors based on the pixels in the first captured image and the second captured image that have a brightness equal to or greater than the predetermined value.

[0014] The image processing method according to the present disclosure includes the steps of supporting an object on a support unit so that it can rotate around a rotation axis, focusing light reflected by the object with an objective lens, causing a drive unit to change the Z position, which is the relative position between the object and the focusing position of the objective lens in the optical axis direction of the objective lens, causing an acquisition unit to acquire an image of the object via the objective lens, and a control unit that controls the support unit and the drive unit causing the acquisition unit to acquire a plurality of the imaged images, causing an identification unit to identify pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of the imaged images, each of which has a different Z position and a different rotation angle of the object, storing the identified pixel positions in a memory unit as high-brightness information together with the Z position and the rotation angle in each imaged image, and causing a generation unit to generate image information of the object based on the stored plurality of high-brightness information.

[0015] In the above image processing method, in the step of causing the acquisition unit to acquire the captured image, the control unit may cause the acquisition unit to acquire multiple captured images of the end portion of the object by rotating the object around the rotation axis using the support unit while changing the Z position using the drive unit.

[0016] In the above image processing method, in the step of supporting the object on the support unit, the drive unit moves the object in a direction perpendicular to the rotation axis, and in the step of having the acquisition unit acquire the captured image, the control unit may rotate the object around the rotation axis using the support unit, change the radial position using the drive unit in a first direction perpendicular to the rotation axis, and keep the Z position constant at the first position, and cause the acquisition unit to acquire the multiple captured images of the main surface of the object.

[0017] In the above image processing method, in the step of having the acquisition unit acquire the captured image, the control unit rotates the object around the rotation axis using the support unit, changes the radial position using the drive unit in a second direction opposite to the first direction, and keeps the Z position constant at a second position, so that the acquisition unit acquires multiple captured images of the main surface of the object, wherein the second position is different from the first position, and the difference between the second position and the first position may be within the focal depth of an optical system including the objective lens.

[0018] The image processing method according to the present disclosure includes the steps of supporting an object on a support unit so that it can rotate around a rotation axis; focusing light reflected by the object with an objective lens; changing the Z position, which is the relative position between the object and the focusing position of the objective lens in the optical axis direction of the objective lens, with a drive unit; causing an acquisition unit to acquire an image of the object via the objective lens; a control unit that controls the support unit and the drive unit causing the acquisition unit to acquire a plurality of the imaged images; causing an identification unit to identify pixel positions, which are positions of pixels where the brightness is greater than or equal to a predetermined value, in a plurality of imaged images where the Z positions are different and the rotation angles of the object are different; and causing a generation unit to generate image information of the object based on the pixels where the brightness is greater than or equal to the predetermined value. In the step of causing the generation unit to generate image information of the object, the generation unit generates image information of the object at the specific rotation angle based on pixels where the brightness is greater than or equal to the predetermined value in a plurality of imaged images where the rotation angle is a specific rotation angle and the Z positions are different from each other.

[0019] In the above image processing method, in the step of generating the image information by the generation unit, the generation unit may generate the image information of the object at a plurality of specific rotation angles based on pixels that have a brightness greater than or equal to a predetermined value in a plurality of captured images in which the rotation angle is a first rotation angle and the Z positions are different from each other, and pixels that have a brightness greater than or equal to a predetermined value in a plurality of captured images in which the rotation angle is a second rotation angle and the Z positions are different from each other.

[0020] In the image processing method, in the step of changing the Z position to the driving unit, the driving unit changes an optical axis angle, which is the angle of the optical axis of the objective lens with respect to a plane perpendicular to the rotation axis; and in the step of causing the identifying unit to identify the pixel position, the identifying unit identifies pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of the captured images, each of which has a different Z position, rotation angle, and optical axis angle; and in the step of causing the generating unit to generate the image information, the generating unit may generate the image information of the end of the object at the specific rotation angle based on pixels where the brightness is equal to or greater than a predetermined value in a plurality of the captured images, each of which has a rotation angle that is a specific rotation angle, a first optical axis angle, and a different Z position, and pixels where the brightness is equal to or greater than a predetermined value in a plurality of the captured images, each of which has a rotation angle that is a specific rotation angle, a second optical axis angle, and a different Z position.

[0021] In the image processing method, in the step of acquiring the captured images, the control unit may cause the acquisition unit to acquire a first captured image from a first light receiving unit that receives light of a first wavelength corresponding to a first color in the reflected light, and to acquire a second captured image from a second light receiving unit that receives light of a second wavelength that corresponds to a second color in the reflected light; in the step of causing the identification unit to identify the pixel positions, the identification unit may identify first-wavelength pixel positions that are the pixel positions where the luminance is equal to or greater than a predetermined value in a plurality of the first captured images that have different Z positions, and identify second-wavelength pixel positions that are the pixel positions where the luminance is equal to or greater than a predetermined value in a plurality of the second captured images that have different Z positions; and in the step of causing the generation unit to generate the image, the generation unit may generate a color image of the edge of the object represented in a plurality of colors based on the first-wavelength high-luminance information and the second-wavelength high-luminance information.

[0022] According to the present disclosure, it is possible to provide an image processing device and an image processing method that can measure information about an object quickly and accurately.

[0023] 1 is a configuration diagram illustrating an inspection apparatus according to embodiment 1. FIG. 2 is a plan view illustrating a stage in the inspection apparatus according to embodiment 1. FIG. 3 is a configuration diagram illustrating an imaging unit in the inspection apparatus according to embodiment 1. FIG. 4 is a block diagram illustrating an image processing apparatus according to embodiment 1. FIG. 5 is a diagram illustrating an inspection image acquired by an acquisition unit in the image processing apparatus according to embodiment 1, where the horizontal axis indicates a rotation angle and the vertical axis indicates pixels at which the edge of the wafer is imaged. FIG. 6 is a diagram illustrating a profile of the edge of the wafer generated by a generation unit in the image processing apparatus according to embodiment 1. FIG. 7 is a flowchart illustrating an image processing method using the image processing apparatus according to embodiment 1. FIG. 8 is a flowchart illustrating an inspection method using the inspection apparatus according to embodiment 1. FIG. 9 is a configuration diagram illustrating an image processing apparatus according to embodiment 2. FIG. 10 is a cross-sectional view illustrating an object in the image processing apparatus according to embodiment 2. FIG. 11 is a plan view illustrating an object in the image processing apparatus according to embodiment 2. FIG. 12 is a diagram illustrating a position at which the imaging unit captures an image when the support unit rotates in the image processing apparatus according to embodiment 2. FIG. 13 is a diagram illustrating a position at which the imaging unit captures an image when the support unit rotates in the image processing apparatus according to embodiment 2. 1 is a block diagram illustrating an image processing unit according to a second embodiment. FIG. 2 is a diagram illustrating captured images acquired by an acquisition unit in an image processing unit according to a second embodiment, where the horizontal axis indicates a rotation angle and the vertical axis indicates pixels capturing an image of the wafer surface of the wafer. FIG. 3 is a diagram explaining the correspondence between the positions of pixels included in each captured image and the positions on the wafer surface of the wafer when the radial position increases for each sampling time in an image processing unit according to a second embodiment. FIG. 4 is a diagram illustrating a profile of the wafer surface of the wafer generated by a generation unit in an image processing device according to a second embodiment. FIG. 5 is a flowchart illustrating an image processing method using the image processing device according to a second embodiment.

[0024] Hereinafter, a specific configuration of the present embodiment will be described with reference to the drawings. The following description shows a preferred embodiment of the present disclosure, and the scope of the present disclosure is not limited to the following embodiment. In the following description, parts with the same reference numerals indicate substantially the same content.

[0025] (Embodiment 1) An image processing device and an image processing method according to embodiment 1 will be described. First, in <Inspection device>, an inspection device will be described as an example of an optical device. Next, in <Image processing device>, an image processing device provided in an optical device will be described. Next, in <Image processing method> and <Inspection method>, an image processing method using the image processing device and an inspection method as an example of a method of using the optical device will be described.

[0026] The image processing device and image processing method according to an example of the present disclosure may be used for an inspection device as described in the following embodiments, but are not limited to this. For example, the image processing device and image processing method according to an example of the present disclosure may be used as a device (review device) that displays an image (captured image) obtained by illuminating a sample on a display or the like.

[0027] <Inspection device> Fig. 1 is a configuration diagram illustrating an inspection device 1 according to embodiment 1. Fig. 2 is a plan view illustrating a stage 10 in the inspection device 1 according to embodiment 1. Fig. 3 is a configuration diagram illustrating an imaging unit 20 in the inspection device 1 according to embodiment 1.

[0028] 1 to 3, the inspection device 1 includes a stage 10, an imaging unit 20, and an image processing device 30. The inspection device 1 inspects an object. For example, the inspection device 1 inspects an edge of the object.

[0029] The object includes, for example, a wafer WF. In this case, the edge of the object includes the edge WFE of the wafer WF. In the following description, the object is assumed to be a wafer WF. Note that the object is not limited to a wafer WF, and may include plate-like objects such as semiconductor chips and printed circuit boards, or objects other than plate-like objects, as long as the object has an edge.

[0030] The stage 10 places the wafer WF on it. The stage 10 has a stage surface 11. The stage 10 places the wafer WF flat on the stage surface 11. The back surface of the wafer WF contacts the stage surface 11. The stage 10 may have a predetermined set position on the stage surface 11 where the wafer WF is set. For example, when inspecting the wafer WF, the wafer WF may first be fixed at the set position. The wafer WF has a wafer surface WF1. Here, for convenience of explanation of the inspection apparatus 1, an αβγ Cartesian coordinate system is introduced. The plane parallel to the stage surface 11 is defined as the αβ plane. The direction perpendicular to the stage surface 11 is defined as the γ axis direction.

[0031] The stage 10 has, for example, a rotation axis C1. The rotation axis C1 extends, for example, in the γ-axis direction. The rotation axis C1 passes through the wafer WF placed on the stage surface 11. Therefore, the stage 10 rotates the wafer WF around the rotation axis C1. For example, the stage 10 may be connected to a drive unit 12 such as a motor. The drive unit 12 rotates the stage 10 around the rotation axis C1. When the wafer WF rotates on the stage 10, the rotation angle from a predetermined set position is called θ.

[0032] The stage 10 may have a three-axis adjustment mechanism or the like that adjusts the position of the stage 10 and the gradient of the stage surface 11. The stage 10 may also include a sensor 13 such as an encoder that senses the rotation angle θ rotated from a predetermined set position. Furthermore, instead of a driver 22 for the objective lens 21, which will be described later, a driver 12 may move the position of the objective lens 21 relative to the wafer WF.

[0033] The stage 10 is connected to the image processing device 30 via a communication line that includes at least one of a wireless and a wired line. Specifically, the stage 10 is connected in a state in which information including data on the rotation angle θ can be transmitted to the image processing device 30. The stage 10 outputs information such as data on the sensed rotation angle θ to the image processing device 30.

[0034] The imaging unit 20 captures an inspection image of the edge WFE of the wafer WF. The imaging unit 20 includes, for example, an objective lens 21, a drive unit 22, and a light receiving unit 23. The imaging unit 20 may further include a light source 24, a pinhole 25, a beam splitter 26, an optical element 27, an optical element 28, and a sensor 29. Note that, as long as the imaging unit 20 can capture an inspection image of the edge WFE of the wafer WF, any of the above optical components may be replaced with other optical components, or other optical components may be included in addition to the above optical components. The imaging unit 20 captures an inspection image of the edge WFE from reflected light R1 reflected by the edge WFE of the wafer WF.

[0035] The objective lens 21 collects reflected light R1 reflected by the edge WFE of the wafer WF. The reflected light R1 may be illumination light L1 emitted from the light source 24 and reflected by the edge WFE of the wafer WF. The objective lens 21 has an optical axis C2. The direction of the optical axis C2 is called the optical axis direction.

[0036] The driver 22 changes the relative position between the object and the focusing position of the objective lens 21 in the optical axis direction of the objective lens 21. The relative position between the object and the focusing position of the objective lens 21 in the optical axis direction of the objective lens 21 is referred to as the Z position. For example, the driver 22 moves the position of the objective lens 21 in the optical axis direction. The driver 22 may change the relative position between the object and the focusing position of the objective lens 21 in the optical axis direction of the objective lens 21 by changing the shape, position, or attitude of an optical element, changing the focusing distance of the objective lens 21, or the like. For simplicity, the following description will be given using an example in which the driver 22 changes the relative position (Z position) between the object and the focusing position of the objective lens 21 in the optical axis direction of the objective lens 21 by moving the position of the objective lens 21 in the optical axis direction. In addition, the driver 22 changes the angle of the optical axis C2 of the objective lens 21 with respect to a plane perpendicular to the rotation axis C1 of the stage 10. The angle of the optical axis C2 of the objective lens 21 with respect to a plane perpendicular to the rotation axis C1 of the stage 10 is called the optical axis angle Φ.

[0037] The light receiving unit 23 receives the reflected light R1 collected by the objective lens 21. As a result, the imaging unit 20 captures an inspection image from the reflected light R1 reflected by the end WFE of the wafer WF. The light receiving unit 23 may include a first light receiving unit 23 a and a second light receiving unit 23 b. Furthermore, the light receiving unit 23 may further include a third light receiving unit 23 c in addition to the first light receiving unit 23 a and the second light receiving unit 23 b.

[0038] The first light receiving unit 23a receives light of a first wavelength corresponding to a first color of the reflected light R1. The second light receiving unit 23b receives light of a second wavelength corresponding to a second color of the reflected light R1. The third light receiving unit 23c receives light of a third wavelength corresponding to a third color of the reflected light R1. The first color, the second color, and the third color may include, for example, red, blue, and green. In this case, the image capturing unit 20 may include optical elements 27 and 28 having a spectroscopic function, such as dichroic mirrors.

[0039] The optical elements 27 and 28 separate the reflected light R1 into the light of the first wavelength, the light of the second wavelength, and the light of the third wavelength. Note that the optical elements 27 and 28 are not limited to dichroic mirrors, and may be other optical elements such as bandpass filters, as long as they can separate the reflected light R1 into the light of the first wavelength, the light of the second wavelength, and the light of the third wavelength.

[0040] The pinhole 25 is disposed at the exit port of the light source 24 from which the illumination light L1 is emitted. The pinhole 25 is also disposed on the light receiving surface of the light receiving unit 23 (first light receiving unit 23a, second light receiving unit 23b, and third light receiving unit 23c). The beam splitter 26 reflects the illumination light L1 emitted from the light source 24 toward the wafer WF. The beam splitter 26 also transmits reflected light R1 reflected by the edge WFE of the wafer WF toward the light receiving unit 23.

[0041] The imaging unit 20 may have a confocal optical system. Therefore, the imaging unit 20 can capture an image so that the edge WFE of the wafer WF is in focus. However, in this embodiment, the imaging unit 20 may move the Z position of the objective lens 21 without paying attention to the focus during imaging. The brightness of the reflected light R1 from the position of the edge WFE in focus increases. This allows the in-focus Z position to be identified. Therefore, after imaging, various data information such as the in-focus Z position, brightness information, rotation angle θ, optical axis angle Φ, and the sampling time of the image is referenced. A profile of the edge WFE of the wafer WF can be formed based on the referenced various data information. In this way, the imaging unit 20 enables three-dimensional measurement.

[0042] The imaging unit 20 may include a sensor 29 that senses the Z position to which the imaging unit 20 has moved from a predetermined set position. The sensor 29 may sense the optical axis angle Φ that has changed from the predetermined set position.

[0043] The imaging unit 20 is connected to the image processing device 30 via a communication line including at least one of wireless and wired. Specifically, the imaging unit 20 is connected in a state in which information including data such as image data, Z position, rotation angle θ, optical axis angle Φ, sampling time, etc. can be transmitted to the image processing device 30. The imaging unit 20 outputs information such as captured image data, Z position, rotation angle θ, optical axis angle Φ, sampling time, etc. to the image processing device 30.

[0044] <Image Processing Device> Next, the image processing device 30 will be described. Fig. 4 is a block diagram illustrating the image processing device 30 according to the first embodiment. As shown in Fig. 4, the image processing device 30 includes an acquisition unit 31, an identification unit 32, a storage unit 33, a generation unit 34, and a control unit 35. The acquisition unit 31, the identification unit 32, the storage unit 33, the generation unit 34, and the control unit 35 function as an acquisition means, an identification means, a storage means, a generation means, and a control means. The image processing device 30 is an information processing device including a computer such as a PC, a server, or a smartphone, for example.

[0045] The acquisition unit 31 moves the Z position while rotating the wafer WF around the rotation axis C1 on the stage 10, thereby acquiring inspection images of the edge WFE of the wafer WF at a plurality of Z positions from the reflected light R1 collected by the objective lens 21. The inspection images include pixels of the edge WFE corresponding to the rotation angle θ at each Z position.

[0046] 5 is a diagram illustrating an example of an inspection image acquired by the acquisition unit 31 in the image processing device 30 according to the first embodiment, where the horizontal axis represents the rotation angle θ and the vertical axis represents the pixels at which the edge WFE of the wafer WF is imaged. As shown in FIG. 5, the acquisition unit 31 acquires a plurality of inspection images each having a different Z position. Each inspection image corresponds the rotation angle θ of the edge WFE of the wafer WF to the pixels at which the edge WFE is imaged at the rotation angle θ. The rotation angle θ in the inspection image may be in the range of 0° to 360° so as to correspond to the entire circumference of the edge WFE of the wafer WF, or may be within a predetermined range.

[0047] 5 shows the case where the optical axis angle Φ is Φ=Φ1. On the other hand, the acquisition unit 31 may acquire inspection images when the optical axis angle Φ is changed. For example, the acquisition unit 31 may acquire an inspection image with an optical axis angle Φ=+90°, such as when the edge WFE of the wafer WF is imaged from the +γ-axis direction. The acquisition unit 31 may also acquire an inspection image with an optical axis angle Φ=-90°, such as when the edge WFE of the wafer WF is imaged from the −γ-axis direction. In this way, the optical axis angle Φ of the inspection image may include a range from −90° to +90°.

[0048] The acquisition unit 31 may acquire the inspection image from the first light receiving unit 23 a that receives light of the first wavelength. The inspection image acquired from the first light receiving unit 23 a is called the first inspection image. Therefore, in this case, the acquisition unit 31 acquires the first inspection image.

[0049] For example, assume that the acquisition unit 31 acquires a first inspection image as shown in Fig. 5. In this case, the acquisition unit 31 may acquire a second inspection image and a third inspection image similar to those shown in Fig. 5. Here, the inspection image acquired from the second light receiving unit 23b that receives light of the second wavelength in the reflected light R1 is referred to as the second inspection image, and the inspection image acquired from the third light receiving unit 23c that receives light of the third wavelength in the reflected light R1 is referred to as the third inspection image. The first inspection image, the second inspection image, and the third inspection image may each include multiple inspection images with different Z positions.

[0050] As shown in FIG. 5 , the identifying unit 32 identifies pixel positions in the inspection image where the luminance is equal to or greater than a predetermined value. The pixel positions where the luminance is equal to or greater than a predetermined value are referred to as pixel positions P. Note that some reference numerals are omitted in FIG. 5 to avoid cluttering the drawing. As described above, the inspection image includes a plurality of inspection images with different Z positions. For example, FIG. 5 illustrates a case where the Z positions are Z=Z1, Z2, and Z3. The identifying unit 32 may identify pixel positions P where the luminance is equal to or greater than a predetermined value in the inspection images with Z positions Z=Z1, Z2, and Z3. The identifying unit 32 may also identify pixel positions P where the luminance is equal to or greater than a predetermined value in a plurality of inspection images obtained by changing the optical axis angle Φ. The above is an example of a process for identifying pixel positions P where the luminance is equal to or greater than a predetermined value in a plurality of inspection images with different Z positions and different object rotation angles θ. The identifying unit 32 may identify pixel positions P where the luminance is equal to or greater than a predetermined value in a plurality of inspection images, each of which has a different Z position and a different rotation angle θ of the object, based on the plurality of inspection images corresponding to Z positions and pixels capturing images of the end portions at the Z positions. The identifying unit 32 may identify pixel positions P where the goodness of an evaluation parameter for a pixel is equal to or greater than a predetermined value. A luminance equal to or greater than a predetermined value is an example of the goodness of an evaluation parameter for a pixel being equal to or greater than a predetermined value. The evaluation parameters for a pixel may include, in addition to luminance, parameters obtained by normalizing luminance, etc. Furthermore, identifying pixel positions where the goodness of an evaluation parameter for a luminance or a pixel is equal to or greater than a predetermined value may also include identifying pixel positions where the goodness of an evaluation parameter for a luminance or a pixel is less than a predetermined value and excluding the pixel from processing.

[0051] Whether the quality of the brightness or pixel evaluation parameter is equal to or higher than a predetermined level may be determined by using the brightness or pixel evaluation parameter when an image is formed in a state where the object is focused to a predetermined degree as a threshold value. Here, the state where the object is focused to a predetermined degree may mean just focus, or may include a state including an amount of defocus that is acceptable in terms of design.

[0052] The identifying unit 32 may identify a first-wavelength pixel position P1 in a plurality of first inspection images each having a different Z position acquired by the acquiring unit 31. The identifying unit 32 may identify a second-wavelength pixel position in a plurality of second inspection images each having a different Z position acquired by the acquiring unit 31, or may identify a third-wavelength pixel position in a plurality of third inspection images each having a different Z position. Here, a pixel position in the first inspection image where the luminance is equal to or greater than a predetermined value is referred to as a first-wavelength pixel position P1, a pixel position in the second inspection image where the luminance is equal to or greater than a predetermined value is referred to as a second-wavelength pixel position P2 (not shown), and a pixel position in the third inspection image where the luminance is equal to or greater than a predetermined value is referred to as a third-wavelength pixel position P3 (not shown).

[0053] The storage unit 33 stores the identified pixel position P together with the Z position, rotation angle θ, and sampling time in each inspection image as high-brightness information. The storage unit 33 may store the optical axis angle Φ together with the pixel position P as high-brightness information. The storage unit 33 may store high-brightness information at multiple optical axis angles Φ.

[0054] The storage unit 33 may store the first-wavelength pixel position P1 together with the Z position, rotation angle θ, and sampling time as first-wavelength high-brightness information for each first inspection image. Furthermore, the storage unit 33 may store the second-wavelength pixel position P2 together with the Z position, rotation angle θ, and sampling time as second-wavelength high-brightness information for each second inspection image, and may store the third-wavelength pixel position P3 together with the Z position, rotation angle θ, and sampling time as third-wavelength high-brightness information for each third inspection image.

[0055] The generating unit 34 generates image information of the edge WFE of the wafer WF based on the stored plurality of pieces of high-brightness information. The image information may include, for example, a profile of the edge WFE. Generating image information based on the high-brightness information by the generating unit 34 may include the generating unit 34 outputting brightness level information or height information indicating a physical height based on the Z position at that time based on the brightness at the pixel position P indicated by the high-brightness information. Generating image information based on the high-brightness information by the generating unit 34 may also include the generating unit 34 acquiring statistical values ​​such as an average or standard deviation based on the brightness at the plurality of pixel positions P indicated by the plurality of pieces of high-brightness information, or acquiring values ​​interpolated based on the brightness at the plurality of pixel positions P, and outputting the acquired statistical values ​​as brightness level information or height information converted into a physical height.

[0056] FIG. 6 is a diagram illustrating a profile of the edge WFE of the wafer WF generated by the generation unit 34 in the image processing device 30 according to the first embodiment. FIG. 6 illustrates a case where the rotation angle θ is θ=θ1. FIG. 6 also illustrates a case where the optical axis angle Φ is multiple values ​​Φ1 to Φ5. Note that the optical axis angle Φ being −90° to +90° is an example. Dividing the optical axis angle Φ from −90° to +90° into Φ1 to Φ5 is also an example. As shown in FIG. 6, the generation unit 34 may generate a profile of the cross section of the edge WFE as image information. As described above, a pixel whose brightness (the pixel's evaluation parameter) is equal to or greater than a predetermined value may be considered to be appropriately focused on the edge WFE at that Z position, e.g., just focused. In this case, the generation unit 34 can generate a profile of the cross section of the edge WFE based on the Z position at that time.

[0057] The generating unit 34 may generate image information about the rotation angle θ of the entire circumference of the edge WFE of the wafer WF based on the high-brightness information. For example, the generating unit 34 may generate a cross-sectional profile about the rotation angle θ of the entire circumference of the edge WFE of the wafer WF.

[0058] The generation unit 34 may also generate image information based on high-brightness information at multiple optical axis angles Φ relative to the wafer WF. For example, the generation unit 34 may generate a cross-sectional profile of the edge WFE based on high-brightness information at multiple optical axis angles Φ relative to the wafer WF. For example, the generation unit 34 may generate a profile of the edge WFE from the back surface to the front surface of the wafer WF by generating a profile over a range of optical axis angles Φ = -90° to +90° with respect to a plane perpendicular to the rotation axis C1. Furthermore, the generation unit 34 may generate a cross-sectional profile of the edge WFE from the front surface to the back surface of the wafer WF over the entire circumference of the edge WFE of the wafer WF by generating a cross-sectional profile of the edge WFE for the rotation angle θ of the entire circumference of the edge WFE of the wafer WF.

[0059] The generation unit 34 may generate a color image of the edge WFE of the wafer WF expressed in multiple colors based on the first wavelength high-brightness information and the second wavelength high-brightness information. The generation unit 34 may also generate a color image of the edge WFE of the wafer WF expressed in multiple colors based on the first wavelength high-brightness information, the second wavelength high-brightness information, and the third wavelength high-brightness information. The generation unit 34 may generate a reference image of the edge WFE of the wafer WF based on the image information. Here, the reference image is an image of the edge WFE of an ideal wafer WF (a wafer WF that can be said to be defect-free) used to inspect the edge WFE of the wafer WF for defects, etc.

[0060] The control unit 35 controls the operations of the acquisition unit 31, the identification unit 32, the storage unit 33, and the generation unit 34 in the image processing device 30. The control unit 35 may also control the operations of the drive unit 12 of the stage 10, the drive unit 22 of the imaging unit 20, the light receiving unit 23, and the light source 24 in the inspection device 1. The control unit 35 may inspect the wafer WF for defects, etc., based on the image information. For example, the inspection target wafer WF may be inspected by comparing image information of an ideal wafer WF with image information of the inspection target wafer WF. Instead of the image information, the inspection target wafer WF may be inspected using a profile, color image, or image of the edge WFE generated based on the image information.

[0061] <Image Processing Method> Next, a description will be given of an image processing method using the image processing device 30 according to this embodiment. Fig. 7 is a flowchart illustrating an image processing method using the image processing device 30 according to the first embodiment.

[0062] 7 , the controller 35 causes the acquiring unit 31 to acquire inspection images. Specifically, the controller 35 causes the stage 10 to rotate the wafer WF around the rotation axis C1 while moving the Z position, thereby causing the acquiring unit 31 to acquire inspection images of the edge WFE of the wafer WF at multiple Z positions from the reflected light R1 collected by the objective lens 21. In step S11, the controller 35 may cause the acquiring unit 31 to acquire a first inspection image from the first light receiving unit 23 a that receives light of a first wavelength in the reflected light R1, to acquire a second inspection image from the second light receiving unit 23 b that receives light of a second wavelength, and to acquire a third inspection image from the third light receiving unit 23 c that receives light of a third wavelength.

[0063] Next, as shown in step S12, the control unit 35 causes the identifying unit 32 to identify pixel positions P. Specifically, the control unit 35 causes the identifying unit 32 to identify pixel positions P where the luminance is equal to or greater than a predetermined value in a plurality of inspection images having different Z positions. In step S12, the control unit 35 may cause the identifying unit 32 to identify first-wavelength pixel positions P1 in a plurality of first inspection images, second-wavelength pixel positions P2 in a plurality of second inspection images, and third-wavelength pixel positions P3 in a plurality of third inspection images. The control unit 35 may cause the identifying unit 32 to identify pixel positions where the luminance is equal to or greater than a predetermined value in a plurality of inspection images having different Z positions and different rotation angles θ of the object.

[0064] Next, as shown in step S13, the control unit 35 stores high-brightness information in the storage unit 33. Specifically, the control unit 35 stores the identified pixel position P together with the Z position, rotation angle θ, and sampling time in each inspection image as high-brightness information in the storage unit 33. In step S13, the control unit 35 may store the optical axis angle Φ together with the pixel position P as high-brightness information in the storage unit 33. The control unit 35 may also store high-brightness information for multiple optical axis angles Φ in the storage unit 33.

[0065] Furthermore, the control unit 35 may store the first-wavelength pixel position P1 in the memory unit 33 together with the Z position, rotation angle θ, and sampling time as information when the first wavelength is high in each first inspection image, store the second-wavelength pixel position P2 in the memory unit 33 together with the Z position, rotation angle θ, and sampling time as information when the second wavelength is high in each second inspection image, and store the third-wavelength pixel position P3 in the memory unit 33 together with the Z position, rotation angle θ, and sampling time as information when the third wavelength is high in each third inspection image.

[0066] Next, as shown in step S14, the control unit 35 causes the generation unit 34 to generate image information regarding the edge WFE of the wafer WF based on the stored multiple pieces of high-brightness information. In step S14, the control unit 35 may cause the generation unit 34 to generate image information based on the high-brightness information at multiple optical axis angles Φ relative to the wafer WF. The control unit 35 may also cause the generation unit 34 to generate image information regarding the rotation angle θ of the entire circumference of the edge WFE of the wafer WF based on the high-brightness information. Furthermore, in step S14, the control unit 35 may cause the generation unit 34 to generate a color image of the edge WFE of the wafer WF expressed in multiple colors based on the first-wavelength high-brightness information, second-wavelength high-brightness information, and third-wavelength high-brightness information.

[0067] <Inspection Method> Next, a description will be given of an inspection method using the inspection device 1 according to this embodiment. Fig. 8 is a flow chart illustrating an inspection method using the inspection device 1 according to the first embodiment.

[0068] 8, the wafer WF is rotated on the stage 10. Specifically, for example, the control unit 35 drives the drive unit 12 of the stage 10 to rotate the wafer WF on the stage 10 around the rotation axis C1.

[0069] Next, as shown in step S22, the reflected light R1 reflected by the edge WFE of the wafer WF is collected by the objective lens 21. Specifically, for example, the control unit 35 drives the drive unit 22 to control the position of the objective lens 21 so that the objective lens 21 collects the reflected light R1.

[0070] Next, as shown in step S23, the Z position is moved by the drive unit 22. Specifically, for example, the control unit 35 drives the drive unit 22 to move the Z position in the optical axis direction.

[0071] Next, as shown in step S24, the control unit 35 causes the imaging unit 20 to capture an inspection image. For example, the control unit 35 causes the light receiving unit 23 to receive reflected light and capture the inspection image.

[0072] Next, as shown in step S25, the inspection image is subjected to image processing by the image processing device 30. The image processing method using the image processing device 30 is as described above. Note that the method may also include a step of inspecting the object based on the image information.

[0073] Next, the effects of this embodiment will be described. The image processing device 30 of this embodiment acquires an inspection image of the edge WFE by changing the Z position of the objective lens 21, which collects reflected light R1 from the edge WFE of the wafer WF, while rotating the wafer WF around the rotation axis C1. The image processing device 30 then identifies pixel positions P from the inspection image where the brightness is equal to or greater than a predetermined value, and generates image information of the edge WFE based on the pixel positions P. This allows the image processing device 30 to obtain profiles of the edge WFE for multiple rotation angles θ. Specifically, it is possible to obtain profile information of the edge WFE around the entire periphery of the wafer WF. Therefore, the image processing device 30 can measure information about an object such as a wafer WF quickly and accurately.

[0074] There is a technique for forming a profile of the edge WFE by measuring the position of the edge WFE of the wafer WF from a position focused by a confocal optical system while rotating the stage 10. However, with this method, after measurement of the position of the edge WFE at an arbitrary rotation angle θ is completed, the data at that rotation angle θ is not used for measuring the position of the edge WFE at a subsequent rotation angle θ.

[0075] In contrast, the image processing device 30 of this embodiment stores data of a plurality of inspection images acquired by the acquisition unit 31 in the storage unit 33. Therefore, if a singular point due to a measurement error or the like is found in the profile of the edge WFE, correction such as interpolation can be performed on the singular point based on the data around the singular point stored in the storage unit 33, thereby improving the accuracy of the profile of the edge WFE of the wafer WF.

[0076] Recent semiconductor devices are stacked three-dimensionally, improving their integration density. This can lead to larger irregularities in the surface shape of the wafer WF. When a wafer WF on which such semiconductor devices are formed is measured using a confocal optical system, only the focal length (depth of field) range is in focus. Therefore, the in-focus portion of the semiconductor device may be limited. Furthermore, in this case, the autofocus function may not be fully utilized. While a method of widening the focal length range is conceivable, this may result in a reduction in resolution.

[0077] In contrast, the image processing device 30 of this embodiment scans the objective lens 21 in the optical axis direction regardless of the focal length of the objective lens 21. This makes it possible to acquire an image in focus on the object, thereby eliminating the need for an autofocus function.

[0078] In related devices for capturing color images, multiple light receiving elements corresponding to different colors are used to capture the color image. Each light receiving element must be in focus at the same time. If the light receiving elements are not in focus at the same time, the generated color image will not display the correct colors due to chromatic aberration.

[0079] In contrast, the image processing device 30 of this embodiment generates a color image based on the focused first wavelength high brightness information, second wavelength high brightness information, and third wavelength high brightness information at each light receiving unit 23 (first light receiving unit 23 a, second light receiving unit 23 b, and third light receiving unit 23 c) ​​while scanning the objective lens 21 in the optical axis direction. In other words, the first inspection image, second inspection image, and third inspection image are combined to generate a color image. This enables high-speed and high-precision color image generation.

[0080] Generally, in the semiconductor manufacturing process, it is important to be able to quickly analyze factors that reduce yield. For example, when searching for factors that reduce yield in wafer WF, various information is required, such as identifying killer defects and measuring the profile shape of the wafer itself. Inspecting and measuring these requires the use of multiple devices, which consumes a lot of time and money.

[0081] The image processing device 30 and inspection device 1 of this embodiment use a device equipped with a confocal optical microscope and can simultaneously generate a high-resolution color image and a cross-sectional profile of the wafer WF. Specifically, as described above, the inspection device 1 may be configured to include a confocal optical imaging unit 20, a stage 10 having a rotation axis C1, and multiple light receiving units 23 that detect different wavelengths. While rotating the stage 10 at high speed, a scan is performed by moving the objective lens 21 in the direction of the optical axis C2 relative to the focus position.

[0082] At this time, it is possible to obtain a profile of the entire circumference of the wafer WF and an all-in-focus image of the high-definition confocal optical system by referring to brightness information at the timing when the focus is achieved by the multiple light receiving units 23, position information of the Z position of the objective lens 21, and angle information of the rotation angle θ of the stage 10. Furthermore, by combining all-in-focus images of multiple wavelengths (for example, RGB), it is possible to generate a color image and simultaneously generate a height image in which the position information of the Z position is converted into image gradation.

[0083] With this configuration, the image processing device and inspection device 1 of this embodiment can be expected to have the following effects.

[0084] The first benefit is cost reduction. Because the profile information of the wafer WF and the inspection image used for defect inspection are captured simultaneously, the number of devices used can be reduced, leading to reduced man-hours and costs.

[0085] The second is to obtain a profile of unevenness larger than the focal length. The image processing device 30 of this embodiment can obtain focused images even for wafers WF with large uneven shapes. Recent semiconductor devices tend to be formed three-dimensionally, and many wafers WF have surface unevenness of several tens of micrometers or more. For this reason, it is difficult to obtain an image in focus over the entire surface with the focal length of a typical confocal optical microscope. To obtain an image in focus over the entire surface, it is possible to sacrifice resolution and use a method with a wider focal length. However, this would result in a decrease in resolution. In this embodiment, an image in focus over the entire surface with high resolution can be obtained.

[0086] The third benefit is the reduction of chromatic aberration in color images. In a confocal optical system, brightness increases where the image is in focus and decreases where it is not. Therefore, if there is a discrepancy in the timing at which the images are focused between multiple cameras, the colors will not be displayed correctly. In this embodiment, an image in which each light-receiving unit 23 is in focus can be obtained by scanning along the optical axis. Therefore, by combining the images of each color later, a color image in which all colors are in focus can be generated.

[0087] (Embodiment 2) Next, an image processing device according to embodiment 2 will be described. In the following, description of the same configuration as in embodiment 1 may be omitted. The image processing device of this embodiment may be called an inspection device. Also, the inspection device 1 of embodiment 1 described above may be called an image processing device. In that case, the image processing device 30 will be called an image processing unit 30a. Below, after describing the <image processing device> and <image processing unit>, the <image processing method> will be described.

[0088] <Image Processing Device> FIG. 9 is a configuration diagram illustrating an image processing device 2 according to a second embodiment. FIG. 10 is a cross-sectional view illustrating an example of an object in the image processing device 2 according to the second embodiment. FIG. 11 is a plan view illustrating an example of an object in the image processing device 2 according to the second embodiment. As shown in FIGS. 9 to 11, the image processing device 2 includes a support unit 40, a drive unit 12, a drive unit 22, an imaging unit 20, and an image processing unit 30a. The image processing device 2 processes, for example, captured images of the object. The image processing device 2 may inspect the object. In that case, the captured images include an inspection image. The image processing device 2 may process captured images of the edge of the object and captured images of the main surface of the object.

[0089] The object includes, for example, a wafer WF. In this case, the edge of the object includes the edge WFE of the wafer WF. The main surface of the object includes the wafer surface WF1 of the wafer WF. Note that the main surface of the object does not exclude including the back surface of the wafer WF. In the following description, the object may be referred to as a wafer WF. Note that the object is not limited to a wafer WF, and may include plate-like objects such as semiconductor chips and printed circuit boards, or objects other than plate-like objects, as long as it has an edge and a main surface.

[0090] 11, for ease of explanation of the image processing device 2, an rθ polar coordinate system is introduced with the rotation axis C1 as the center for the αβ plane in the αβγ Cartesian coordinate system. The radial position r indicates the distance from the rotation axis C1. The rotation angle θ indicates the angle between the α axis and the −α axis direction.

[0091] The support unit 40 supports the object. The support unit 40 may include, for example, a stage 10. The stage 10 supports a wafer WF placed on a stage surface 11. The stage 10 may be connected to a drive unit 12 such as a motor. The drive unit 12 rotates the stage 10 around a rotation axis C1. The stage 10 may have a three-axis adjustment mechanism or the like that adjusts the position of the stage 10 and the gradient of the stage surface 11. The drive unit 12 may move the stage 10 in a direction perpendicular to the rotation axis C1. Alternatively, the drive unit 12 may move the stage 10 in a direction parallel to the rotation axis C1. The drive unit 12 may be capable of changing the relative position between the object and the focusing position of the objective lens 21 in a direction parallel to the rotation axis C1.

[0092] Therefore, the support unit 40 supports the object so that it can rotate around the rotation axis C1. The support unit 40 also supports the object so that it can move in a direction perpendicular to the rotation axis C1. For example, the support unit 40 supports the object so that it can move in the α-axis direction. The support unit 40 may sense the amount of movement in the α-axis direction using the sensor 13. The amount of movement of the support unit 40 in the α-axis direction corresponds to the radial position r at which the imaging unit 20 images the wafer surface WF1.

[0093] Furthermore, the support unit 40 supports the object so that it can move in a direction parallel to the rotation axis C1. For example, the support unit 40 supports the object so that it can move in the γ-axis direction. When the main surface of the object is imaged, the support unit 40 may sense the Z position from the amount of movement in the γ-axis direction using the sensor 13. Note that the support unit 40 is not limited to the stage 10, as long as it can support the object so that it can rotate around the rotation axis C1 and can support it so that it can move in a direction perpendicular to and parallel to the rotation axis C1.

[0094] The support unit 40 is connected to the image processing unit 30a via a communication line that includes at least one of a wireless and a wired line. The support unit 40 is connected in a state in which information including data on the radial position r, the rotation angle θ, and the Z position can be transmitted to the image processing unit 30a. The support unit 40 outputs this information.

[0095] The driver 12 rotates the stage 10 around the rotation axis C1. Therefore, the driver 12 rotates the object around the rotation axis C1. The driver 12 may change the position of the stage 10 by driving a three-axis adjustment mechanism or the like. The driver 12 can change the relative position (referred to as the radial position r) between the object and the focusing position of the objective lens 21 in a direction perpendicular to the rotation axis C1. For example, the driver 12 moves the stage 10 in the α-axis direction perpendicular to the rotation axis C1. Therefore, the driver 12 moves the object in the α-axis direction. The driver 12 also moves the stage 10 in the γ-axis direction parallel to the rotation axis C1. Therefore, the driver 12 moves the object in the γ-axis direction.

[0096] As in the Z scan shown in FIG. 10 , the driver 12 may fix the Z position when changing the radial position r in a direction perpendicular to the rotation axis C1. As an example, when changing the radial position r in a direction perpendicular to the rotation axis C1, the driver 12 may fix the position of the objective lens 21 in the γ-axis direction. When changing the radial position r in a direction perpendicular to the rotation axis C1, the driver 12 may fix the Z position to a first position, a second position, or the like. For example, when changing the radial position r in a direction perpendicular to the rotation axis C1, the driver 12 may fix the position of the objective lens 21 in the γ-axis direction to a first position, a second position, or the like. Specifically, as shown by the support unit 40 on the left side of FIG. 11 , when moving the support unit 40 in the −α-axis direction while rotating the support unit 40, the driver 12 fixes the Z position to a first position. In contrast, as shown by the support unit 40 on the right side of FIG. 11 , when the driver 12 moves the support unit 40 in the +α-axis direction while rotating it, the driver 12 fixes the Z position at the second position. The first position and the second position may be different in the γ-axis direction. The difference between the first position and the second position in the γ-axis direction is preferably within the focal depth of the optical system including the objective lens 21. When the driver 12 changes the radial position r in a direction perpendicular to the rotation axis C1, the driver 12 may set the optical axis angle Φ to approximately 90°. That is, when the driver 12 changes the radial position r in a direction perpendicular to the rotation axis C1, the driver 12 may set the optical axis angle Φ so that the optical axis C2 of the objective lens 21 and the rotation axis C1 are approximately parallel. Note that, in the above description, the driver 12 changes the radial position r in a direction perpendicular to the rotation axis C1, fixes the Z position at the first position, the second position, etc., or sets the optical axis angle Φ. However, instead of or in addition to this, the driver 22 may perform these operations.

[0097] The imaging unit 20 captures an image of an object. The imaging unit 20 captures images of the edge WFE and wafer surface WF1 of the wafer WF. The imaging unit 20 includes, for example, an objective lens 21, a drive unit 22, and a light-receiving unit 23. As described above, the imaging unit 20 may further include a light source 24, a pinhole 25, a beam splitter 26, an optical element 27, an optical element 28, and a sensor 29. Note that, as long as the imaging unit 20 can capture images of the edge WFE and wafer surface WF1 of the wafer WF, any of the above optical components may be replaced with other optical components, or other optical components may be included in addition to the above optical components. The imaging unit 20 captures an image of the edge WFE from the reflected light R1 reflected by the end WFE of the wafer WF. The imaging unit 20 also captures an image of the wafer surface WF1 from the reflected light R1 reflected by the wafer surface WF1. For simplicity, this may be simply described as the imaging unit 20 capturing an image of the edge WFE and wafer surface WF1 from the reflected light R1 reflected by the edge WFE and wafer surface WF1 of the wafer WF. Similarly, for simplicity, the reflected light R1 reflected by at least one of the edge WFE and wafer surface WF1 of the wafer WF may be simply described as the reflected light R1 reflected by the edge WFE and wafer surface WF1 of the wafer WF.

[0098] The objective lens 21 collects reflected light R1 reflected by the object. Specifically, for example, the objective lens 21 collects reflected light R1 reflected by the edge WFE and wafer surface WF1 of the wafer WF. The reflected light R1 may be illumination light L1 emitted from the light source 24 reflected by at least one of the edge WFE and wafer surface WF1 of the wafer WF. The objective lens 21 has an optical axis C2. The direction of the optical axis C2 is called the optical axis direction.

[0099] At least one of the driving units 12 and 22 can change the Z position, which is the relative position between the object and the focusing position of the objective lens 21 in the optical axis direction of the objective lens 21. For example, the driving unit 22 moves the position of the objective lens 21 in the optical axis direction. At least one of the driving units 12 and 22 can also change the optical axis angle Φ, which is the angle of the optical axis C2 of the objective lens 21 with respect to a plane perpendicular to the rotation axis C1 of the stage 10. Furthermore, at least one of the driving units 12 and 22 can change the radial position r, which is the relative position between the object and the focusing position of the objective lens 21 in the direction perpendicular to the rotation axis C1 of the stage 10. For example, the driving unit 12 changes the radial position r of the objective lens 21 by moving the stage 10 in the α-axis direction.

[0100] 12 and 13 are diagrams illustrating positions G1 and G2 at which the imaging unit 20 captures an image when the support unit 40 rotates in the image processing device 2 according to the second embodiment. As shown in FIG. 12 , at sampling time t=t1, information about position G1 at which the imaging unit 20 captures an image includes sampling time t1, radial position r1, and rotation angle θ1. As shown in FIG. 13 , at sampling time t=t2, rotation of the support unit 40, such as the stage 10, causes the rotation angle θ to change from θ1 to θ2. At the same time, movement of the support unit 40, such as the stage 10, in the −α-axis direction causes the radial position r to change from r1 to r2. Information about position G2 at which the imaging unit 20 captures an image includes sampling time t2, radial position r2, and rotation angle θ2.

[0101] The imaging unit 20 may have a confocal optical system. This allows the imaging unit 20 to image the edge WFE and wafer surface WF1 of the wafer WF so that they are in focus. However, in this embodiment, the imaging unit 20 and the like may move the Z position of the objective lens 21 without focusing on focus during imaging. The brightness of reflected light R1 from the focused positions of the edge WFE and wafer surface WF1 increases. Therefore, the focused Z position can be identified. Therefore, after imaging, various data information such as the focused radial position r, Z position, brightness information, evaluation parameters, rotation angle θ, optical axis angle Φ, and sampling time of the image are referenced. Based on the referenced various data information, profiles of the edge WFE and wafer surface WF1 of the wafer WF can be formed. In this way, the imaging unit 20 enables three-dimensional measurement.

[0102] The imaging unit 20 is connected to the image processing unit 30a via a communication line that includes at least one of wireless and wired lines. Specifically, the imaging unit 20 is connected in a state in which information including data such as image data, radial position r, Z position, rotation angle θ, optical axis angle Φ, and sampling time can be transmitted to the image processing unit 30a. The imaging unit 20 outputs this information to the image processing unit 30a.

[0103] <Image Processing Unit> Next, the image processing unit 30a will be described. Fig. 14 is a block diagram illustrating the image processing unit 30a according to the second embodiment. As shown in Fig. 14, the image processing unit 30a includes an acquisition unit 31, an identification unit 32, a storage unit 33, a generation unit 34, and a control unit 35, similar to the image processing device 30 described above. Note that the image processing unit 30a does not necessarily have to include the storage unit 33.

[0104] The acquisition unit 31 acquires a captured image of the object via the objective lens 21. The acquisition unit 31 acquires a captured image of the end or main surface of the object via the objective lens 21 by changing the Z position while rotating the object around the rotation axis C1 using at least one of the drive units 12 and 22. The acquisition unit 31 acquires a plurality of captured images each having a different Z position and a different rotation angle θ of the object.

[0105] 15 is a diagram illustrating an example of captured images acquired by the acquisition unit 31 in the image processing unit 30a according to the second embodiment, where the horizontal axis represents the rotation angle θ and the vertical axis represents the pixels capturing an image of an area on the wafer surface WF1 of the wafer WF at a predetermined radial position r. As shown in FIG. 15 , the acquisition unit 31 acquires multiple captured images with different Z positions and radial positions r. Each captured image corresponds to the rotation angle θ of the position G on the wafer surface WF1 of the wafer WF captured by the imaging unit 20 and the pixels capturing the image of the wafer surface WF1 at the rotation angle θ. The rotation angle θ in the captured image may include a range of 0° to 360° so as to correspond to the entire circumference surrounding the central axis C1 of the wafer surface WF1 of the wafer WF, or may include a predetermined partial range.

[0106] The acquisition unit 31 may acquire multiple captured images when the radial position r is changed when the Z position is Z=Z1. For example, the acquisition unit 31 may acquire captured images when the radial position r is changed from r1 to r3 or more. Furthermore, the acquisition unit 31 may acquire multiple captured images when the Z position is moved in the γ-axis direction at a predetermined distance within the focal depth of the optical system including the objective lens 21, such as a first position Z1, a second position Z2, a third position Z3, etc. In other words, when the Z position is the first position Z1, multiple captured images may be acquired at radial positions r1 to r3 or more; when the Z position is the second position Z2, multiple captured images may be acquired at radial positions r1 to r3 or more; and when the Z position is the third position Z3, multiple captured images may be acquired at radial positions r1 to r3 or more. For each captured image, the horizontal axis indicates the rotation angle θ, and the vertical axis indicates the pixels capturing an image of an area on the wafer surface WF1 of the wafer WF at a predetermined radial position r.

[0107] 16 is a diagram illustrating the correspondence relationship between the positions of pixels included in each captured image and the positions on the wafer surface WF1 of the wafer WF when the radial position r increases at each sampling time t in the image processing unit 30a according to the second embodiment. Here, r01<r02<r03<r0N<r0E.

[0108] At sampling time t=t11, pixels included in the captured image correspond to positions on the wafer surface WF1 of the wafer WF at radial position r=r01 and rotation angle θ=0°. At a subsequent sampling time t=t13, pixels included in the captured image correspond to positions on the wafer surface WF1 of the wafer WF at radial position r=r02 and rotation angle θ=360° (which is also 0°). At sampling time t=t12 between time t11 and time t13, pixels included in the captured image may correspond to positions on the wafer surface WF1 of the wafer WF at radial positions between r01 and r02 and rotation angles between 0° and 360°.

[0109] At sampling time t=t21 (which may be the same time as t13), the pixels included in the captured image correspond to positions on the wafer surface WF1 of the wafer WF at the radial position r=r02 and the rotation angle θ=0°. At a subsequent sampling time t=t23, the pixels included in the captured image correspond to positions on the wafer surface WF1 of the wafer WF at the radial position r=r03 and the rotation angle θ=360° (which is also 0°).

[0110] At sampling time t=tN1, the pixels included in the captured image correspond to positions on the wafer surface WF1 of the wafer WF at the radial position r=r0N and the rotation angle θ=0°. At a subsequent sampling time t=tN3, the pixels included in the captured image correspond to positions on the wafer surface WF1 of the wafer WF at the radial position r=r0E and the rotation angle θ=360° (which is also 0°).

[0111] For example, the radial position r01 may be a radial position where the measurement target area closest to the center of the wafer surface WF1 is included in the captured image when the radial position r is increased by a small amount from the radial position r01 at a rotation angle of 0°. The radial position r0E may be a radial position where the measurement target area closest to the edge WFE of the wafer WF is included in the captured image when the radial position r is decreased by a small amount from the radial position r0E at a rotation angle of 0°. This allows the measurement target area on the wafer surface WF1 to be included in the captured image without any shortage.

[0112] For simplicity, the pixels included in the captured image are arranged in a line extending in one direction in Fig. 16, but this is not limiting. Also, Fig. 16 shows an example in which the radial position r increases sequentially, but if the radial position r decreases sequentially, the above explanation can be followed in reverse.

[0113] According to the example shown in FIG. 16, the acquisition unit 31 can acquire the captured image shown in FIG. 15 based on captured images of the wafer surface WF1 of the wafer WF at multiple sampling times t.

[0114] The acquisition unit 31 may acquire captured images from the first light receiving unit 23a that receives light of a first wavelength. The captured image acquired from the first light receiving unit 23a is referred to as the first captured image. The acquisition unit 31 may acquire captured images from the second light receiving unit 23b that receives light of a second wavelength. The captured image acquired from the second light receiving unit 23b is referred to as the second captured image. The acquisition unit 31 may acquire captured images from the third light receiving unit 23c that receives light of a third wavelength. The captured image acquired from the third light receiving unit 23c is referred to as the third captured image. The acquisition unit 31 may acquire second and third inspection images similar to those in FIG. 5. The first, second, and third captured images may each include a plurality of inspection images having different radial positions r and Z positions.

[0115] The control unit 35 controls the support unit 40 and the drive units 12 and 22, and causes the acquisition unit 31 to acquire multiple captured images. The control unit 35 also controls the operations of the acquisition unit 31, the identification unit 32, the storage unit 33, and the generation unit 34. In the above-described first embodiment, the control unit 35 causes the acquisition unit 31 to acquire multiple captured images of the end portion of the object by changing the Z position using at least one of the drive units 12 and 22 while rotating the object around the rotation axis C1 using the support unit 40.

[0116] On the other hand, in this embodiment, the control unit 35 rotates the object around the rotation axis C1 using the support unit 40, causes the driver 22 to change the radial position r in a first direction perpendicular to the rotation axis, and keeps the Z position constant at the first position, causing the acquisition unit 41 to acquire multiple captured images of the object's main surface. Furthermore, while rotating the object around the rotation axis C1 using the support unit 40, the control unit 35 causes the driver 22 to change the radial position r in a second direction perpendicular to the rotation axis, and keeps the Z position constant at the second position, causing the acquisition unit 41 to acquire multiple captured images of the object's main surface. Here, the second direction is the opposite direction to the first direction. The second position is a position different from the first position. Furthermore, the difference between the first position and the second position is within the focal depth of the optical system of the imaging unit 20, including the objective lens 21. In this embodiment, the driver 12 may be driven instead of or in addition to the driver 22.

[0117] The identifying unit 32 identifies pixel positions P, which are positions of pixels where the luminance is equal to or greater than a predetermined value, in a plurality of captured images that are each different in Z position and rotation angle θ of the object. The identifying unit 32 may identify pixel positions P, which are positions of pixels where the luminance is equal to or greater than a predetermined value, in a plurality of captured images that are each different in radial position r, Z position, rotation angle θ, and optical axis angle Φ. Note that, as described above, luminance equal to or greater than a predetermined value is an example of the quality of an evaluation parameter for a pixel being equal to or greater than a predetermined value.

[0118] The identifying unit 32 may identify first-wavelength pixel positions P1 in a plurality of first captured images that are each acquired by the acquiring unit 31 and have different radial positions r or Z positions. The identifying unit 32 may identify second-wavelength pixel positions in a plurality of second captured images that are each acquired by the acquiring unit 31 and have different radial positions r or Z positions, or may identify third-wavelength pixel positions in a plurality of third captured images that are each acquired by the acquiring unit 31 and have different radial positions r or Z positions. Here, a pixel position in the first captured image where the luminance is equal to or greater than a predetermined value is referred to as a first-wavelength pixel position P1, a pixel position in the second captured image where the luminance is equal to or greater than a predetermined value is referred to as a second-wavelength pixel position P2 (not shown), and a pixel position in the third captured image where the luminance is equal to or greater than a predetermined value is referred to as a third-wavelength pixel position P3 (not shown).

[0119] The storage unit 33 stores the identified pixel position P together with the Z position and rotation angle θ in each captured image as high-brightness information. The storage unit 33 may store the identified pixel position P together with the radial position r, Z position, rotation angle θ, optical axis angle Φ, and sampling time in each captured image as high-brightness information.

[0120] The generation unit 34 may generate image information of the object based on the stored plurality of pieces of high-brightness information. Alternatively, the generation unit 34 may generate image information of the object based on pixels having a predetermined brightness or higher. Specifically, the generation unit 34 may generate image information of the object at a specific rotation angle θ based on pixels having a predetermined brightness or higher in a plurality of captured images having different Z positions at a specific rotation angle θ.

[0121] That is, the generation unit 34 may generate image information of the object at a plurality of specific rotation angles θ based on pixels whose brightness is equal to or greater than a predetermined value in a plurality of captured images whose Z positions are different and whose rotation angle θ is a first rotation angle θ1, and pixels whose brightness is equal to or greater than a predetermined value in a plurality of captured images whose Z positions are different and whose rotation angle θ is a second rotation angle θ2. The generation unit 34 may generate the above-described image information for a plurality of radial positions r. In this manner, the generation unit 34 may generate image information of the main surface of the object. The image information may include a profile of the main surface of the object.

[0122] FIG. 17 is a diagram illustrating a profile of the wafer surface WF1 of the wafer WF generated by the generation unit 34 in the image processing device 2 according to the second embodiment. FIG. 17 illustrates a case where the rotation angle θ is θ=θ1. FIG. 17 also illustrates a case where the radial position r is multiple values ​​r1 to r5. As shown in FIG. 17, the generation unit 34 may generate a profile of the cross section of the wafer surface WF1 of the wafer WF as image information. As described above, a pixel whose brightness (the goodness of the pixel evaluation parameter) is equal to or greater than a predetermined value may be considered to be appropriately focused, for example, just focused, on the surface of the edge WFE or the wafer surface WF1 at that Z position. Therefore, the generation unit 34 can generate a profile of the cross section of the wafer surface WF1 or the edge WFE of the wafer WF based on the Z position at that time.

[0123] The generating unit 34 may generate image information about the rotation angle θ of the entire circumference of the main surface of the object based on the high-brightness information or pixels whose brightness is equal to or greater than a predetermined value. For example, the generating unit 34 may generate a cross-sectional profile about the rotation angle θ of the entire circumference of the wafer surface WF1 of the wafer WF.

[0124] The generation unit 34 may generate image information of the end of the object, as in the first embodiment described above. That is, the generation unit 34 generates image information of the end of the object at a specific rotation angle θ based on pixels whose brightness is equal to or greater than a predetermined value in a plurality of captured images in which the rotation angle θ is a specific rotation angle θ, the optical axis angle Φ is a first optical axis angle, and the Z positions are different from each other, and based on pixels whose brightness is equal to or greater than a predetermined value in a plurality of captured images in which the rotation angle θ is a specific rotation angle θ, the optical axis angle Φ is a second optical axis angle, and the Z positions are different from each other. Generating image information based on high-brightness information or pixels whose brightness is equal to or greater than a predetermined value by the generation unit 34 may include the generation unit 34 outputting brightness level information for the brightness of pixels whose brightness is equal to or greater than the predetermined value, or height information indicating a physical height based on the Z position at that time. Furthermore, the generation unit 34 generating image information based on high-brightness information or pixels having a brightness equal to or higher than a predetermined value may include the generation unit 34 obtaining statistical values ​​such as the average or standard deviation of multiple brightnesses of multiple pixels having a brightness equal to or higher than a predetermined value, or obtaining values ​​interpolated based on the multiple brightnesses, and outputting the obtained values ​​as brightness level information or height information converted into physical height. The generation unit may generate a color image of the object represented in multiple colors based on pixels having a brightness equal to or higher than a predetermined value in the first captured image, the second captured image, etc.

[0125] The control unit 35 may inspect the wafer WF for defects, etc., based on the image information. For example, the inspection target wafer WF may be inspected by comparing image information of an ideal wafer WF with image information of the inspection target wafer WF. Instead of the image information, the inspection target wafer WF may be inspected using a profile, a color image, or an image of the edge WFE generated based on the image information.

[0126] <Image Processing Method> Next, an image processing method will be described. Fig. 18 is a flowchart illustrating an image processing method using the image processing device 2 according to the second embodiment.

[0127] The object is supported as shown in step S31 of Fig. 18. For example, the control unit 35 causes the support unit 40 to support the object so that it can rotate around the rotation axis C1.

[0128] Next, as shown in step S32, the reflected light R1 is collected by the objective lens 21. Specifically, for example, the control unit 35 drives the drive unit 22 to control the position of the objective lens 21 so that the reflected light R1 reflected by the object is collected by the objective lens 21.

[0129] Next, as shown in step S33, the Z position is changed by the driving unit 22 or the like. Specifically, for example, the control unit 35 drives the driving unit 22 to cause the driving unit 22 to change the Z position, which is the relative position between the object and the focusing position of the objective lens 21 in the optical axis direction of the objective lens 21. The driving unit 22 or the like may change the optical axis angle Φ of the objective lens 21 with respect to a plane orthogonal to the rotation axis C1.

[0130] Next, as shown in step S34, the control unit 35 controls the acquisition unit 31 to acquire the captured image. For example, the control unit 35 controls the acquisition unit 31 to acquire the captured image. As a result, the control unit 35 controls the acquisition unit 31 to acquire the captured image of the object via the objective lens 21. The control unit 35 may also control the acquisition unit 31 to acquire multiple captured images.

[0131] The control unit 35 may rotate the object around the rotation axis C1 using the support unit 40 while changing the Z position using at least one of the drive unit 12 and the drive unit 22, thereby causing the acquisition unit 31 to acquire multiple captured images of the end of the object.

[0132] The control unit 35 may rotate the object around the rotation axis C1 using the support unit 40, change the radial position in a first direction perpendicular to the rotation axis using the drive unit, and keep the Z position constant at the first position, thereby causing the acquisition unit 31 to acquire multiple images of the main surface of the object.

[0133] The control unit 35 may rotate the object around the rotation axis C1 using the support unit 40, change the radial position in a second direction perpendicular to the rotation axis using the drive unit, and keep the Z position constant at the second position, thereby causing the acquisition unit 31 to acquire multiple images of the main surface of the object.

[0134] Next, as shown in step S35, a pixel position is identified. For example, the control unit 35 causes the identification unit 32 to identify a pixel position P, which is a pixel position where the brightness is equal to or greater than a predetermined value, in a plurality of captured images each having a different Z position and a different rotation angle θ of the object. The image processing method of this embodiment may include, between step S35 and step S36, a step of storing the identified pixel position P in the storage unit 33 as high-brightness information together with the radial position r, Z position, rotation angle θ, optical axis angle Φ, and sampling time in each captured image.

[0135] Next, as shown in step S36, image information is generated. Specifically, the control unit 35 causes the generation unit 34 to generate image information of the object based on pixels whose brightness is equal to or greater than a predetermined value. The generation unit 34 generates image information of the object at a specific rotation angle θ based on pixels whose brightness is equal to or greater than a predetermined value in multiple captured images where the rotation angle θ is a specific rotation angle θ and the Z positions are different from each other. The generation unit 34 may generate image information of the object at multiple specific rotation angles θ based on pixels whose brightness is equal to or greater than a predetermined value in multiple captured images where the rotation angle θ is a first rotation angle θ1 and the Z positions are different from each other, and pixels whose brightness is equal to or greater than a predetermined value in multiple captured images where the rotation angle θ is a second rotation angle θ2 and the Z positions are different from each other. Note that the control unit 35 may cause the generation unit 34 to generate image information of the object based on multiple pieces of high-brightness information stored.

[0136] Although the embodiments of the present invention have been described above, the present invention includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the above-described embodiments.

[0137] (Supplementary Note 1) An image processing device comprising: an acquisition unit that acquires inspection images of the end of the object at a plurality of Z positions from the reflected light collected by the objective lens by moving a Z position, which is a position of the objective lens in the optical axis direction of the objective lens, while rotating the object around the rotation axis on a stage having the rotation axis; an identification unit that identifies pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of inspection images each having a different Z position and a different rotation angle of the object; a storage unit that stores the identified pixel positions together with the Z position and the rotation angle in each inspection image as high-brightness information; and a generation unit that generates image information of the end of the object based on the stored plurality of pieces of high-brightness information. (Supplementary Note 2) The image processing device according to Supplementary Note 1, wherein the storage unit stores, as the high-brightness information, an optical axis angle, which is the angle of the optical axis of the objective lens with respect to a plane orthogonal to the rotation axis, together with the pixel position. (Supplementary Note 3) The image processing device according to Supplementary Note 2, wherein the object includes a plate-like object, the storage unit stores the high-brightness information at a plurality of the optical axis angles, and the generation unit generates the image information based on the high-brightness information at a plurality of the optical axis angles for the object. (Supplementary Note 4) The image processing device according to Supplementary Note 1, wherein the generation unit generates the image information for the rotation angle of the entire circumference at the end of the object based on the high-brightness information.(Supplementary Note 5) The acquisition unit acquires a first inspection image from a first light receiving unit that receives light of a first wavelength corresponding to a first color in the reflected light, and acquires a second inspection image from a second light receiving unit that receives light of a second wavelength corresponding to a second color in the reflected light; the identification unit identifies first-wavelength pixel positions that are pixel positions where the luminance is equal to or greater than a predetermined value in the plurality of first inspection images having different Z positions, and identifies second-wavelength pixel positions that are pixel positions where the luminance is equal to or greater than a predetermined value in the plurality of second inspection images having different Z positions; the storage unit stores the first-wavelength pixel positions together with the Z position and the rotation angle as first-wavelength high-luminance information in each first inspection image, and stores the second-wavelength pixel positions together with the Z position and the rotation angle as second-wavelength high-luminance information in each second inspection image; and the generation unit generates a color image of the edge of the object represented in a plurality of colors based on the first-wavelength high-luminance information and the second-wavelength high-luminance information. The image processing device according to Supplementary Note 1. (Supplementary Note 6) The image processing device according to Supplementary Note 5, wherein the acquisition unit further acquires a third inspection image from a third light receiving unit that receives light of a third wavelength corresponding to a third color in the reflected light, the identification unit further identifies third-wavelength pixel positions that are the pixel positions where the brightness is equal to or greater than a predetermined value in a plurality of the third inspection images having different Z positions, the storage unit further stores the third-wavelength pixel positions together with the Z position and the rotation angle as third-wavelength high-brightness information in each of the third inspection images, and the generation unit generates a color image of the edge of the object expressed in a plurality of colors based on the first-wavelength high-brightness information, the second-wavelength high-brightness information, and the third-wavelength high-brightness information. (Supplementary Note 7) The image processing device according to Supplementary Note 1, wherein the object includes a wafer, and the edge includes an edge of the wafer. (Supplementary Note 8) The image processing device according to any one of Supplements 1 to 7, further comprising a control unit that inspects the object based on the image information.(Supplementary Note 9) An image processing method comprising: a first step of causing an acquisition unit to acquire inspection images of the end of the object at a plurality of Z positions from the reflected light focused by the objective lens, by moving a Z position, which is the position of the objective lens in the optical axis direction of the objective lens, while rotating the object around the rotation axis on a stage having the rotation axis; a second step of causing an identification unit to identify pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of inspection images each having a different Z position and a different rotation angle of the object; a third step of causing a memory unit to store the identified pixel positions together with the Z position and the rotation angle in each inspection image as high brightness information; and a fourth step of causing a generation unit to generate image information of the end of the object based on the stored plurality of pieces of high brightness information. (Supplementary Note 10) The image processing method according to Supplementary Note 9, wherein in the third step, an optical axis angle, which is the angle of the optical axis of the objective lens with respect to a plane orthogonal to the rotation axis, is stored together with the pixel position as the high-brightness information. (Supplementary Note 11) The image processing method according to Supplementary Note 10, wherein the object includes a plate-like object, and in the third step, the high-brightness information for a plurality of the optical axis angles is stored, and in the fourth step, the image information is generated based on the high-brightness information for the plurality of the optical axis angles with respect to the object. (Supplementary Note 12) The image processing method according to Supplementary Note 9, wherein in the fourth step, the image information for the rotation angle of the entire circumference at the end of the object is generated based on the high-brightness information.(Supplementary Note 13) In the first step, a first inspection image is acquired from a first light receiving unit that receives light of a first wavelength corresponding to a first color in the reflected light, and a second inspection image is acquired from a second light receiving unit that receives light of a second wavelength corresponding to a second color in the reflected light; in the second step, first-wavelength pixel positions are identified in the plurality of first inspection images having different Z positions, where the pixel positions are where the brightness is equal to or greater than a predetermined value; and second-wavelength pixel positions are identified in the plurality of second inspection images having different Z positions, where the pixel positions are where the brightness is equal to or greater than a predetermined value; in the third step, the first-wavelength pixel positions are stored together with the Z position and the rotation angle as first-wavelength high-brightness information in each first inspection image; and the second-wavelength pixel positions are stored together with the Z position and the rotation angle as second-wavelength high-brightness information in each second inspection image; and in the fourth step, The image processing method of Supplementary Note 9, wherein a color image of the edge of the object expressed in a plurality of colors is generated based on the first wavelength high-brightness information and the second wavelength high-brightness information. (Supplementary Note 14) The image processing method of Supplementary Note 13, wherein in the first step, a third inspection image is further acquired from a third light receiving unit that receives light of a third wavelength corresponding to a third color in the reflected light, in the second step, third-wavelength pixel positions are further identified as the pixel positions where the brightness is equal to or greater than a predetermined value in the plurality of third inspection images having different Z positions, in the third step, the third-wavelength pixel positions are further stored together with the Z position and the rotation angle as third-wavelength high-brightness information for each third inspection image, and in the fourth step, a color image of the edge of the object expressed in a plurality of colors is generated based on the first wavelength high-brightness information, the second wavelength high-brightness information, and the third wavelength high-brightness information. (Supplementary Note 15) The image processing method according to Supplementary Note 9, wherein the object includes a wafer, and the end portion includes an edge of the wafer. (Supplementary Note 16) The image processing method according to any one of Supplementary Notes 9 to 15, further comprising a step of inspecting the object based on the image information.

[0138] This application claims priority based on Japanese Patent Application No. 2024-020110, filed February 14, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0139] REFERENCE SIGNS LIST 1 Inspection device 2 Image processing device 10 Stage 11 Stage surface 12 Drive unit 13 Sensor 20 Imaging unit 21 Objective lens 22 Drive unit 23 Light receiving unit 23a First light receiving unit 23b Second light receiving unit 23c Third light receiving unit 24 Light source 25 Pinhole 26 Beam splitter 27, 28 Optical element 29 Sensor 30 Image processing device 30a Image processing unit 31 Acquisition unit 32 Identification unit 33 Storage unit 34 Generation unit 35 Control unit 40 Support unit C1 Rotation axis C2 Optical axis L1 Illumination light R1 Reflected light WF Wafer WF1 Wafer surface WFE Edge θ Rotation angle Φ Optical axis angle

Claims

1. An image processing device comprising: a support unit that supports an object rotatably around a rotation axis; an objective lens that focuses light reflected by the object; a drive unit that can change the Z position, which is the relative position between the object and the focusing position of the objective lens in the optical axis direction of the objective lens; an acquisition unit that acquires an image of the object via the objective lens; a control unit that controls the support unit and the drive unit to cause the acquisition unit to acquire a plurality of the imaged images; an identification unit that identifies pixel positions where the brightness is equal to or greater than a predetermined value in a plurality of imaged images that each have a different Z position and a different rotation angle of the object; a memory unit that stores the identified pixel positions together with the Z position and the rotation angle in each imaged image as high brightness information; and a generation unit that generates image information of the object based on the stored plurality of high brightness information.

2. The image processing device according to claim 1, wherein the control unit causes the acquisition unit to acquire multiple captured images of the end of the object by rotating the object around the rotation axis using the support unit and changing the Z position using the drive unit.

3. The image processing device described in claim 1, wherein the drive unit is capable of changing the radial position, which is the relative position between the object and the focusing position of the objective lens, in a direction perpendicular to the rotation axis, and the control unit, while rotating the object around the rotation axis using the support unit, changes the radial position using the drive unit in a first direction perpendicular to the rotation axis and keeps the Z position constant at the first position, and causes the acquisition unit to acquire multiple captured images of the main surface of the object.

4. The image processing device described in claim 3, wherein the control unit rotates the object around the rotation axis using the support unit, changes the radial position using the drive unit in a second direction opposite to the first direction, and keeps the Z position constant at the second position, and causes the acquisition unit to acquire multiple captured images of the main surface of the object, the second position being different from the first position, and the difference between the second position and the first position being within the focal depth of an optical system including the objective lens.

5. An image processing device comprising: a support unit that supports an object rotatably around a rotation axis; an objective lens that focuses light reflected by the object; a drive unit that can change the Z position, which is the relative position between the object and the focusing position of the objective lens in the optical axis direction of the objective lens; an acquisition unit that acquires an image of the object via the objective lens; a control unit that controls the support unit and the drive unit and causes the acquisition unit to acquire a plurality of the imaged images; an identification unit that identifies pixel positions where the brightness is equal to or greater than a predetermined value in a plurality of imaged images that are each at a different Z position and a different rotation angle of the object; and a generation unit that generates image information of the object based on the pixels where the brightness is equal to or greater than the predetermined value in a plurality of imaged images that are at a specific rotation angle and at different Z positions.

6. The image processing device described in claim 5, wherein the generation unit generates the image information of the object at a plurality of specific rotation angles based on pixels whose brightness is a predetermined value or higher in a plurality of captured images whose rotation angle is a first rotation angle and whose Z positions are different from each other, and pixels whose brightness is a predetermined value or higher in a plurality of captured images whose rotation angle is a second rotation angle and whose Z positions are different from each other.

7. The image processing device described in claim 5, wherein the drive unit is capable of changing the optical axis angle, which is the angle of the optical axis of the objective lens with respect to a plane perpendicular to the rotation axis; the identification unit identifies pixel positions, which are positions of pixels where the brightness is greater than or equal to a predetermined value, in the plurality of captured images where the Z position, the rotation angle, and the optical axis angle are different from each other; and the generation unit generates the image information of the edge of the object at the specific rotation angle based on: pixels where the brightness is greater than or equal to a predetermined value in the plurality of captured images where the rotation angle is the specific rotation angle, the optical axis angle is a first optical axis angle, and the Z position is different from each other; and pixels where the brightness is greater than or equal to a predetermined value in the plurality of captured images where the rotation angle is the specific rotation angle, the optical axis angle is a second optical axis angle, and the Z position is different from each other.

8. The image processing device described in claim 1 or 5, wherein the acquisition unit acquires a first captured image from a first light receiving unit that receives light of a first wavelength corresponding to a first color in the reflected light, and acquires a second captured image from a second light receiving unit that receives light of a second wavelength that corresponds to a second color in the reflected light, the identification unit identifies first wavelength pixel positions that are pixel positions where the brightness is equal to or greater than a predetermined value in the plurality of first captured images that have different Z positions, and identifies second wavelength pixel positions that are pixel positions where the brightness is equal to or greater than a predetermined value in the plurality of second captured images that have different Z positions, and the generation unit generates a color image of the object represented in a plurality of colors based on pixels in the first captured image and the second captured image that have a brightness equal to or greater than the predetermined value.

9. An image processing method comprising the steps of: supporting an object on a support section so that it can rotate around a rotation axis; focusing light reflected by the object with an objective lens; causing a drive section to change a Z position, which is the relative position between the object and the focusing position of the objective lens in the optical axis direction of the objective lens; causing an acquisition section to acquire an image of the object via the objective lens; a control section, which controls the support section and the drive section, causing the acquisition section to acquire a plurality of the imaged images; causing an identification section to identify pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of imaged images, each of which has a different Z position and a different rotation angle of the object; storing the identified pixel positions together with the Z position and the rotation angle in each image in a memory section as high brightness information; and causing a generation section to generate image information of the object based on the stored plurality of high brightness information.

10. An image processing method as described in claim 9, wherein in the step of causing the acquisition unit to acquire the captured images, the control unit causes the acquisition unit to acquire multiple captured images of the end of the object by rotating the object around the rotation axis using the support unit while changing the Z position using the drive unit.

11. The image processing method of claim 9, wherein in the step of supporting the object on the support unit, the drive unit moves a radial position, which is the relative position between the object and the focusing position of the objective lens, in a direction perpendicular to the rotation axis, and in the step of acquiring the captured image on the acquisition unit, the control unit, while rotating the object around the rotation axis using the support unit, changes the radial position using the drive unit in a first direction perpendicular to the rotation axis and keeps the Z position constant at the first position, thereby causing the acquisition unit to acquire the multiple captured images of the main surface of the object.

12. The image processing method of claim 11, wherein in the step of causing the acquisition unit to acquire the captured images, the control unit causes the support unit to rotate the object around the rotation axis, while causing the drive unit to change the radial position in a second direction opposite to the first direction, and keeps the Z position constant at a second position, causing the acquisition unit to acquire multiple captured images of the main surface of the object, wherein the second position is different from the first position, and the difference between the second position and the first position is within the focal depth of an optical system including the objective lens.

13. An image processing method comprising the steps of: supporting an object on a support section so that it can rotate around a rotation axis; focusing light reflected by the object with an objective lens; changing the Z position, which is the relative position between the object and the focusing position of the objective lens in the optical axis direction of the objective lens, with a drive section; causing an acquisition section to acquire an image of the object via the objective lens; a control section, which controls the support section and the drive section, causing the acquisition section to acquire a plurality of the captured images; causing an identification section to identify pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of captured images, each of which has a different Z position and a different rotation angle of the object; and causing a generation section to generate image information of the object based on the pixels where the brightness is equal to or greater than the predetermined value, wherein in the step of causing the generation section to generate image information, the generation section generates image information of the object at the specific rotation angle based on pixels where the brightness is equal to or greater than a predetermined value in a plurality of captured images, each of which has a specific rotation angle and different Z positions.

14. An image processing method as described in claim 13, wherein in the step of causing the generation unit to generate, the generation unit generates the image information of the object at a plurality of specific rotation angles based on pixels whose brightness is a predetermined value or higher in a plurality of captured images whose rotation angle is a first rotation angle and whose Z positions are different from each other, and pixels whose brightness is a predetermined value or higher in a plurality of captured images whose rotation angle is a second rotation angle and whose Z positions are different from each other.

15. The image processing method of claim 13, wherein in the step of changing the Z position by the driving unit, the driving unit changes the optical axis angle, which is the angle of the optical axis of the objective lens with respect to a plane perpendicular to the rotation axis; and in the step of identifying the pixel position by the identifying unit, the identifying unit identifies pixel positions, which are positions of pixels where the brightness is equal to or greater than a predetermined value, in a plurality of captured images where the Z position, the rotation angle, and the optical axis angle are different from each other; and in the step of generating by the generating unit, the generating unit generates the image information of the edge of the object at the specific rotation angle based on: pixels where the brightness is equal to or greater than a predetermined value in a plurality of captured images where the rotation angle is a specific rotation angle, the optical axis angle is a first optical axis angle, and the Z positions are different from each other; and pixels where the brightness is equal to or greater than a predetermined value in a plurality of captured images where the rotation angle is a specific rotation angle, the optical axis angle is a second optical axis angle, and the Z positions are different from each other.

16. An image processing method as described in claim 9 or 13, wherein in the step of acquiring the captured image, the control unit causes the acquisition unit to acquire a first captured image from a first light receiving unit that receives light of a first wavelength corresponding to a first color in the reflected light, and to acquire a second captured image from a second light receiving unit that receives light of a second wavelength that corresponds to a second color in the reflected light; in the step of causing the identification unit to identify the pixel positions, the identification unit identifies first wavelength pixel positions that are pixel positions where the brightness is equal to or greater than a predetermined value in a plurality of the first captured images that have different Z positions, and identifies second wavelength pixel positions that are pixel positions where the brightness is equal to or greater than a predetermined value in a plurality of the second captured images that have different Z positions; and in the step of causing the generation unit to generate a color image of the object represented in a plurality of colors based on pixels in the first captured image and the second captured image that have a brightness equal to or greater than the predetermined value.

Images