Device and method for measuring wafer edge area

Abstract

The present invention discloses a wafer edge region measurement device and method. The device includes: a first optical path structure for illuminating a first region to be measured on the wafer edge from the front, the first region to be measured including an EBR milling line; a second optical path structure for illuminating a second region to be measured on the wafer edge from the back, the second region to be measured including an edge vertex, and the second region to be measured and the first region to be measured being arranged opposite to each other with respect to the wafer; an image acquisition unit for performing reflected light imaging of the first region to be measured and through-light imaging of the second region to be measured, thereby acquiring a measured image including the milling line and the edge vertex; and a processing unit for calculating the width of the EBR operating region based on the imaging positional relationship between the milling line and the edge vertex in the measured image. The present invention images the EBR milling line and the wafer edge region in the same image, thereby accurately measuring the width of the EBR operating region between the milling line and the edge vertex, thereby reducing measurement errors.

Description

Technical Field

[0001] The present application relates to the field of wafer detection technology, and in particular to a wafer edge area measurement device and method. Background Art

[0002] During wafer coating, photoresist is flung to the edge of the substrate, resulting in thicker photoresist at the wafer edge than in the center. This can cause the resist to fall off during subsequent processing steps, affecting subsequent steps such as exposure and development, and therefore requires removal. Currently, the primary method for removing photoresist from wafer edges during photolithography is edge bead removal (EBR). After the EBR operation, the effect of the wafer edge area is measured using optical imaging to determine whether the EBR width meets process requirements.

[0003] However, the existing method generally uses bright field illumination to detect the front EBR line, that is, the circular line on the front side of the wafer close to the edge bevel, which is the contour line left after the EBR operation (EBR milling line), such as Figure 1 As shown, when a detector is used to collect images of the EBR operation area at the edge of the wafer, the angles of the reflected light of the illumination light in the flat area and the bevel area of ​​the wafer edge are different, resulting in the reflected light in the bevel area being unable to be collected by the detector, and further resulting in the inability to measure the radial width from the EBR line to the vertex of the wafer edge, thereby affecting the accuracy of the EBR test data. Summary of the Invention

[0004] In view of this, the present application provides a wafer edge area measurement device and a wafer edge area measurement method to solve the problem of inaccurate width measurement results of the EBR operation area after wafer edge stripping.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a wafer edge area measuring device, which includes: a first optical path structure, used to illuminate the first area to be measured on the edge of the wafer from the front, the first area to be measured includes the milling line of the EBR; a second optical path structure, used to illuminate the second area to be measured on the edge of the wafer from the back, the second area to be measured includes the edge vertex, and the second area to be measured and the first area to be measured are arranged opposite to each other with respect to the wafer; an image acquisition unit, used to perform reflected light imaging of the first area to be measured and through light imaging of the second area to be measured, to obtain an image to be measured containing the milling line and the edge vertex; a processing unit, used to calculate the width of the EBR operation area based on the imaging position relationship between the milling line and the edge vertex in the image to be measured.

[0006] As a further improvement of the present application, the first area to be measured covers the plane area and the bevel area of ​​the wafer edge, and the milling line is set in the plane area of ​​the wafer edge; the first optical path structure includes a first illumination light source, and the first illumination light emitted by the first illumination light source is directed to the first area to be measured at an incident angle of less than 90°, and is reflected at different angles in the plane area and the bevel area of ​​the wafer edge, and only the light beam reflected by the plane area of ​​the wafer edge is configured to reach the image acquisition unit.

[0007] As a further improvement of the present application, the second optical path structure includes a second illumination light source, and the second illumination light emitted by the second illumination light source is directed toward the second area to be measured, and a partial beam of the second illumination light is directly directed along the edge vertex to reach the image acquisition unit.

[0008] As a further improvement of the present application, the second illumination light is configured as parallel light, and the optical axis of the second illumination light forms a preset angle with the wafer surface.

[0009] As a further improvement of the present application, it also includes an optical path folding component, which is arranged in the outer space of the back side of the wafer and is used to guide the second illumination light emitted by the second illumination light source to the second area to be measured by folding.

[0010] As a further improvement of the present application, the optical path deflection assembly includes a first reflector and a second reflector, the first reflector is used to receive the second illumination light and guide the second illumination light to the second reflector, and the second reflector is used to redirect the second illumination light to the second area to be measured.

[0011] As a further improvement of the present application, the image acquisition unit includes a CCD camera for simultaneously receiving the optical signals of the first optical path structure and the second optical path structure.

[0012] As a further improvement of the present application, it also includes a rotating platform for carrying the wafer and achieving 360° rotation. The rotating platform drives the wafer to rotate one circle, and all images of the edge of the wafer are captured by the image acquisition unit.

[0013] In order to solve the above technical problems, another technical solution adopted in the present application is: providing a wafer edge area measurement method, which is applied to one of the above-mentioned wafer edge area measurement devices, the wafer edge area measurement device including a first optical path structure, a second optical path structure, an image acquisition unit and a processing unit; the method includes: the first optical path structure illuminates the first area to be measured on the edge of the wafer from the front, and the second optical path structure synchronously illuminates the second area to be measured on the edge of the wafer from the back, the first area to be measured includes the milling line of the EBR, the second area to be measured includes the edge vertex, and the second area to be measured and the first area to be measured are arranged opposite to each other with respect to the wafer; the image acquisition unit performs reflected light imaging on the first area to be measured and directed light imaging on the second area to be measured to obtain an image to be measured containing the milling line and the edge vertex; the processing unit calculates the width of the EBR operation area according to the imaging position relationship between the milling line and the edge vertex in the image to be measured.

[0014] The beneficial effects of this application are:

[0015] The wafer edge area measurement device of the present application utilizes a first optical path structure to illuminate a first area to be measured on the edge of the wafer from the front side to detect the milling line of the EBR, and utilizes a second optical path structure to illuminate a second area to be measured on the edge of the wafer from the back side of the wafer to detect the edge vertex of the wafer, thereby utilizing front bright field imaging and opposite-field imaging to enable the milling line of the EBR and the edge vertex of the wafer to be in the same image, and finally utilizes a processing unit to accurately calculate the width of the EBR operating area according to the distance between the milling line of the EBR and the edge vertex of the wafer, thereby reducing the measurement error of the EBR, and also overcoming the limitation of the existing method that only the width of the area between the milling line of the EBR and the edge bevel line can be obtained directly through front bright field imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the cross-sectional structure of the wafer edge of the present invention;

[0017] Figure 2 1 is a schematic structural diagram of an embodiment of a wafer edge region measuring device according to the present invention;

[0018] Figure 3 2. It is a schematic diagram of the optical axis of an embodiment of a wafer edge area measurement device of the present invention;

[0019] Figure 4 Another schematic diagram of the cross-sectional structure of the wafer edge of the present invention, wherein (a) is a schematic diagram of the arc-shaped edge, and (b) is a schematic diagram of the combination of the arc-shaped slope and the vertical vertex;

[0020] Figure 5 is a schematic diagram of an image collected when only the first light path structure is irradiated;

[0021] Figure 6 is a schematic diagram of an image collected when the first optical path structure and the second optical path structure are irradiated simultaneously;

[0022] Figure 7 It is a schematic flow chart of an embodiment of a wafer edge area measurement method of the present invention;

[0023] Among them, the reference numerals in the figures are:

[0024] 1. The first optical path structure;

[0025] 2. Second optical path structure; 21. Second illumination light source; 22. Optical path deflection assembly; 221. First reflector; 222. Second reflector;

[0026] 3. Image acquisition unit;

[0027] 4. Processing unit. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] The terms "first," "second," and "third" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first," "second," or "third" may explicitly or implicitly include at least one of such features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined. All directional designations in the embodiments of this application (such as up, down, left, right, front, back, etc.) are intended only to illustrate the relative spatial position and movement of components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional designations will also change accordingly. Furthermore, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to such process, method, product, or apparatus.

[0030] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] Figure 2 FIG is a schematic structural diagram of a wafer edge region measuring device according to an embodiment of the present invention. Figure 2 As shown, the wafer edge area measuring device includes a first optical path structure 1 , a second optical path structure 2 , an image acquisition unit 3 and a processing unit 4 .

[0032] The first optical path structure 1 is used to illuminate the first test area on the edge of the wafer from the front (please refer to Figure 1 ), the first area to be measured includes the milling edge line of EBR.

[0033] The second optical path structure 2 is used to illuminate the second area to be measured on the edge of the wafer from the back side (please refer to Figure 1 ), the second area to be tested includes an edge vertex, and the second area to be tested and the first area to be tested are arranged opposite to each other with respect to the wafer.

[0034] The image acquisition unit 3 is used to perform reflected light imaging on the first area to be measured and through-light imaging on the second area to be measured, so as to obtain an image to be measured containing milling edge lines and edge vertices.

[0035] The processing unit 4 is electrically connected to the image acquisition unit 3 and is used to calculate the width of the EBR operation area according to the imaging position relationship between the edge milling line and the edge vertex in the image to be measured.

[0036] Specifically, the first optical path structure 1 is preferably arranged in the outer space of the front side of the wafer, and is used to emit the first illumination light to the front side of the wafer, forming a front bright field illumination of the first area to be measured on the edge of the front side of the wafer, and the reflected light of the front illumination of the first area to be measured is collected by the image acquisition unit 3, and the first area to be measured is imaged by reflected light. The second optical path structure 2 is preferably arranged in the outer space of the back side of the wafer, and the second optical path structure 2 is used to emit the second illumination light to the second area to be measured on the back side of the wafer, and the second illumination light is collected by the image acquisition unit 3, and the second area to be measured is imaged by incident light. It should be noted that the image acquisition unit 3 synchronously collects the optical signals of the first optical path structure 1 and the second optical path structure 2, and synchronously realizes reflected light imaging of the first area to be measured and incident light imaging of the second area to be measured, thereby obtaining the image to be measured containing the milling edge line and the edge vertex. Finally, the processing unit 4 calculates the width of the EBR operation area based on the distance between the milling edge line and the edge vertex in the image to be measured.

[0037] The wafer edge area measurement device of this embodiment utilizes the first optical path structure 1 to illuminate the first area to be measured on the edge of the wafer from the front side to detect the milling line of the EBR, and utilizes the second optical path structure 2 to illuminate the second area to be measured on the edge of the wafer from the back side of the wafer to detect the edge vertex of the wafer, thereby making the milling line of the EBR and the edge vertex of the wafer in the same image through front bright field imaging and through-beam imaging. Finally, the processing unit 4 is used to accurately calculate the width of the EBR operating area according to the distance between the milling line of the EBR and the edge vertex of the wafer, thereby reducing the measurement error of the EBR. At the same time, it can also overcome the limitation of the existing method that only the width of the area between the milling line of the EBR and the edge bevel line can be obtained directly through front bright field imaging.

[0038] Further, such as Figure 1 As shown, the first area to be measured covers the plane area and the bevel area of ​​the wafer edge, and the milling edge line is set in the plane area of ​​the wafer edge.

[0039] The first optical path structure 1 includes a first illumination light source, the first illumination light emitted by the first illumination light source is directed to the first detection area at an incident angle less than 90°, and is reflected at different angles in the flat area and the bevel area of ​​the wafer edge (please refer to Figure 3 ), the light beam reflected only by the planar area at the edge of the wafer is configured to reach the image acquisition unit 3. To improve the imaging effect, the first optical path structure also includes a collimating lens group that can collimate the first illumination light so that the collimated first illumination light enters the first area to be measured.

[0040] Specifically, see Figure 2 The incident angle of the first illumination light emitted by the first illumination light source is acute, i.e., 0° < incident angle < 90°. The first illumination light source illuminates both the planar and inclined surfaces of the first area to be measured. Due to the inclination angle of the inclined surface, the reflection angle of the reflected light from the inclined surface differs from that from the planar surface. Image acquisition unit 3 is positioned in the path of the reflected light from the planar surface, so that image acquisition unit 3 only captures the reflected light from the planar surface and not from the inclined surface.

[0041] It should be noted that there are other Figure 1 and Figure 3 Other structural forms besides the edge structure shown are still applicable to the wafer edge area measurement device provided in this application. Figure 4, illustrating another cross-sectional structure of a wafer edge, with (a) showing a curved edge and (b) showing a combination of a curved slope and a vertical vertex. In (a), the wafer edge consists of a flat region, a curved slope, and a curved vertex, with the vertex at the end of the curved extension forming the edge vertex. In (b), the wafer edge consists of a flat region, a curved slope, and a vertical region, with any point on the vertical region forming an edge vertex. Since the milling line of EBR always exists in the plane area of ​​the wafer edge, no matter whether the shape of the bevel area of ​​the wafer edge is a straight bevel or an arc bevel, it will not affect the first optical path structure in the wafer edge area measurement device to perform oblique illumination and surface reflection on the plane area, and the image acquisition unit can image the entire plane area; since the edge vertex of the wafer edge is at the outermost side of the edge, it is related to the width of the bevel area but not to the shape of the bevel area, so the edge vertex position can be found by using the second optical path structure in the wafer edge area measurement device to perform cross-illumination on the edge vertex, and the image acquisition unit can image the edge vertex; without considering the position of the edge bevel line, as long as the pixel position of the EBR milling line and the pixel position of the edge vertex are identified in the image, the operating area width of the EBR can be converted.

[0042] It can be understood that the wafer edge area measurement device provided in the present application can solve the measurement problem of the EBR operating area width of edges of different shapes, reduce the measurement error of EBR, and at the same time overcome the limitation of the existing method that only the width of the area between the milling edge line and the edge bevel line of EBR can be obtained directly through the front bright field imaging method.

[0043] like Figure 5 As shown, Figure 5 The image captured by the image acquisition unit 3 when only the first illumination light source is used is shown. The boundary line between the black area and the gray area in the figure is the dividing line between the flat area and the inclined area.

[0044] Furthermore, the second optical path structure 2 includes a second illumination light source 21 , and the second illumination light emitted by the second illumination light source 21 is directed toward the second area to be measured, and a partial beam of the second illumination light is directly directed along the edge vertex to reach the image acquisition unit 3 .

[0045] It should be noted that the illumination area of ​​the second illumination light exceeds the boundary of the second area to be measured, so that part of the second illumination light beam is blocked by the second area to be measured and will not be captured by the image acquisition unit 3, while the other part of the unblocked light beam is irradiated along the edge vertex of the wafer to the image acquisition unit 3 and is captured by the image acquisition unit 3. Therefore, when the reflected light of the first illumination light and the second illumination light are captured by the image acquisition unit 3, the following is formed: Figure 6As shown in the image, the first gray area corresponds to the second illumination light, the boundary line between the first gray area and the black area is the wafer edge vertex position, the black area is the bevel area, the boundary line between the black area and the second gray area is the dividing line between the plane area and the bevel area, and the EBR milling line is on the second gray area. By calculating the distance between the wafer edge vertex position in the image to be measured and the EBR milling line, the width of the EBR operating area can be obtained.

[0046] It should be noted that Figure 6 The image shown shows the wafer edge vertex position and the EBR milling line position, making it easy to obtain the number of pixels along the straight line between the two. Since the numerical conversion relationship between a single pixel and the actual distance can be known based on the imaging magnification, the width of the EBR operating area can be calculated based on the number of pixels and the numerical conversion relationship.

[0047] Furthermore, in order to more accurately capture the position of the wafer edge vertex, the second illumination light is configured as parallel light, and the optical axis of the second illumination light forms a preset angle with the wafer surface.

[0048] Specifically, the second illumination light is configured as parallel light, and the parallel light beam has directional consistency, which can reduce light path diffusion and make the edge vertex form a high-contrast light-dark dividing line on the detector (such as Figure 6 The boundary between the first gray area and the black area in the image is obtained), thereby improving the measurement resolution. It should be noted that in order to ensure clear imaging of the wafer edge vertex, the optical axis of the second illumination light is axial to the diameter of the wafer, so that the second illumination light can be irradiated to the image acquisition unit 3 in parallel with the plane where the wafer edge vertex is located. If the optical axis of the second illumination light is not axial to the diameter of the wafer, the second illumination light may irradiate the side area of ​​the wafer edge vertex (see Figure 1 ), resulting in inaccurate positioning of the wafer edge vertex. It should be understood that while the optical axis of the second illumination light is axially related to the wafer diameter, it also forms a predetermined angle with the wafer surface, such as an acute angle, making the optical axis of the second illumination light parallel to the optical axis of the reflected light of the first illumination light.

[0049] Furthermore, during the wafer inspection process, the bottom space of the operating table is limited and does not have the conditions for installing the second illumination light source 21. Therefore, in some embodiments, the second optical path structure 2 also includes an optical path deflection component 22, which is arranged in the outer space on the back side of the wafer and is used to guide the second illumination light emitted by the second illumination light source 21 to the second area to be tested by deflection.

[0050] Specifically, by arranging a reflector in the outer space of the wafer backside, the second illumination light emitted by the second illumination light source 21 is directed to the second area to be measured, thereby eliminating the need to arrange the second illumination light source 21 in the outer space of the wafer backside.

[0051] It should be understood that the first optical path structure 1 may also be arranged at other spatial positions, and a reflector may be provided to guide the illumination light emitted by the first optical path structure 1 to the first area to be measured.

[0052] Furthermore, in some embodiments, the optical path deflection assembly 22 includes a first reflector 221 and a second reflector 222, the first reflector 221 is used to receive the second illumination light and guide the second illumination light to the second reflector 222, and the second reflector 222 is used to redirect the second illumination light to the second area to be measured.

[0053] Furthermore, the image acquisition unit 3 includes a CCD camera for simultaneously receiving the optical signals of the first optical path structure 1 and the second optical path structure 2. The CCD camera here can be a linear array imaging camera or a planar array imaging camera.

[0054] Furthermore, the wafer edge area measurement device further includes a rotating platform for carrying the wafer and achieving 360° rotation. The rotating platform drives the wafer to rotate one circle, and all images of the wafer edge are captured by the image capture unit 3.

[0055] Specifically, after the positions of the first optical path structure 1 and the second optical path structure 2 are calibrated, the wafer is placed on a rotating platform and the rotating platform is used to rotate the wafer so that the edge of the wafer passes through the areas illuminated by the first optical path structure 1 and the second optical path structure 2 in turn, thereby completing the detection of all areas of the wafer edge.

[0056] Figure 7 : is a schematic diagram of the structure of the wafer edge area measurement method of an embodiment of the present invention. The wafer edge area measurement method is applied to the wafer edge area measurement device of one of the above embodiments, and the wafer edge area measurement device includes: a first optical path structure, a second optical path structure, an image acquisition unit and a processing unit. Figure 7 As shown, the wafer edge area measurement method includes:

[0057] Step S1: The first optical path structure illuminates the first area to be measured on the edge of the wafer from the front, and the second optical path structure synchronously illuminates the second area to be measured on the edge of the wafer from the back. The first area to be measured includes the milling line of the EBR, the second area to be measured includes the edge vertex, and the second area to be measured and the first area to be measured are arranged opposite to each other with respect to the wafer.

[0058] Step S2: the image acquisition unit performs reflected light imaging on the first area to be measured and through-light imaging on the second area to be measured to obtain an image to be measured containing milling edge lines and edge vertices.

[0059] Step S3: the processing unit calculates the width of the EBR operation area according to the imaging position relationship between the edge milling line and the edge vertex in the image to be measured.

[0060] The wafer edge area measurement method of this embodiment utilizes a first optical path structure to illuminate a first area to be measured on the edge of the wafer from the front side to detect the milling line of the EBR, and utilizes a second optical path structure to illuminate a second area to be measured on the edge of the wafer from the back side of the wafer to detect the edge vertex of the wafer, thereby utilizing front bright field imaging and through-beam imaging to enable the milling line of the EBR and the edge vertex of the wafer to be in the same image, and finally utilizes a processing unit to accurately calculate the width of the EBR operating area according to the distance between the milling line of the EBR and the edge vertex of the wafer, thereby reducing the measurement error of the EBR, and also overcoming the limitation of the existing method that only the width of the area between the milling line of the EBR and the edge bevel line can be obtained directly through front bright field imaging.

[0061] The above is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A wafer edge area measurement device, characterized in that: It includes: A first optical path structure is used to illuminate a first area to be measured on the edge of the wafer from the front side, wherein the first area to be measured includes a milling edge line of the EBR; a second optical path structure for illuminating a second area to be measured at the edge of the wafer from the back side, wherein the second area to be measured includes an edge vertex, and the second area to be measured and the first area to be measured are arranged opposite to each other with respect to the wafer; An image acquisition unit, configured to perform reflected light imaging on the first area to be measured and through-light imaging on the second area to be measured, to obtain an image to be measured containing the milling edge line and the edge vertex; a processing unit, configured to calculate a width of an EBR operation area according to an imaging position relationship between the edge milling line and the edge vertex in the image to be measured; Wherein: the first area to be measured covers the plane area and the bevel area of ​​the wafer edge, and the milling edge line is set in the plane area of ​​the wafer edge; The first optical path structure includes a first illumination light source, wherein the first illumination light emitted by the first illumination light source is directed toward the first area to be measured at an incident angle of less than 90°, and is reflected at different angles at a planar area and an inclined area of ​​the wafer edge, and only the light beam reflected by the planar area of ​​the wafer edge is configured to reach the image acquisition unit; The second optical path structure includes a second illumination light source and an optical path deflection component, wherein the second illumination light emitted by the second illumination light source is directed toward the second area to be measured, and a partial beam of the second illumination light is directly directed along the edge vertex to reach the image acquisition unit; The light path folding component is arranged in the outer space of the back side of the wafer, and is used to guide the second illumination light emitted by the second illumination light source to the second area to be measured in a folding manner.

2. The wafer edge area measuring device according to claim 1, wherein: The second illumination light is configured as parallel light, and an optical axis of the second illumination light forms a preset angle with the wafer surface.

3. The wafer edge area measuring device according to claim 1, wherein: The optical path deflection assembly includes a first reflector and a second reflector, the first reflector is used to receive the second illumination light and guide the second illumination light to the second reflector, and the second reflector is used to redirect the second illumination light to the second area to be measured.

4. The wafer edge area measuring device according to claim 1, wherein: The image acquisition unit includes a CCD camera, which is used to simultaneously receive the optical signals of the first optical path structure and the second optical path structure.

5. The wafer edge area measuring device according to claim 1, wherein: It also includes a rotating platform for carrying the wafer and realizing 360° rotation. The rotating platform drives the wafer to rotate one circle, and all images of the edge of the wafer are captured by the image capture unit.

6. A wafer edge area measurement method, characterized in that: The wafer edge area measurement device includes a first optical path structure, a second optical path structure, an image acquisition unit, and a processing unit; the method includes: The first optical path structure illuminates a first area to be measured on the edge of the wafer from the front side, and the second optical path structure synchronously illuminates a second area to be measured on the edge of the wafer from the back side, the first area to be measured includes the milling edge line of the EBR, the second area to be measured includes the edge vertex, and the second area to be measured and the first area to be measured are arranged opposite to each other with respect to the wafer; The image acquisition unit performs reflected light imaging on the first area to be measured and through-light imaging on the second area to be measured to obtain an image to be measured containing the milling edge line and the edge vertex; The processing unit calculates the width of the EBR operation area according to the imaging position relationship between the edge milling line and the edge vertex in the image to be measured; The first optical path structure illuminates a first area to be measured at the edge of the wafer from the front, including: configuring the first area to be measured to cover a planar area and a bevel area of ​​the wafer edge, with the milling edge line being located in the planar area of ​​the wafer edge; configuring the first optical path structure to include a first illumination light source, so that a first illumination light emitted by the first illumination light source is directed toward the first area to be measured at an incident angle less than 90°, and is reflected at different angles in the planar area and the bevel area of ​​the wafer edge, and only the light beam reflected by the planar area of ​​the wafer edge is configured to reach the image acquisition unit; Among them, the second optical path structure synchronously illuminates the second area to be measured on the edge of the wafer from the back side, including: configuring the second optical path structure to include a second illumination light source and an optical path deflecting component, so that the second illumination light emitted by the second illumination light source is directed to the second area to be measured, and a partial beam of the second illumination light is directly emitted along the edge vertex to reach the image acquisition unit; and using the optical path deflecting component to guide the second illumination light emitted by the second illumination light source to the second area to be measured by deflecting.

7. The wafer edge area measurement method according to claim 6, characterized in that: When the second illumination light emitted by the second illumination light source is directed toward the second area to be measured, the second illumination light is configured as parallel light with the optical axis forming a preset angle with the wafer surface.

8. The wafer edge area measurement method according to claim 6, characterized in that: The optical path deflecting assembly includes a first reflector and a second reflector, and the optical path deflecting assembly is used to guide the second illumination light emitted by the second illumination light source to the second area to be measured in a deflecting manner, including: receiving the second illumination light by the first reflector and directing the second illumination light to the second reflector; The second reflecting mirror is used to redirect the second illumination light to the second area to be measured.

9. The wafer edge area measurement method according to claim 6, characterized in that: When the image acquisition unit performs reflected light imaging on the first area to be measured and incident light imaging on the second area to be measured, the image acquisition unit is configured to use a CCD camera to simultaneously receive light signals of the first optical path structure and the second optical path structure.

10. The wafer edge area measurement method according to claim 6, characterized in that: Also includes: A rotating platform is used to carry the wafer and perform a 360° rotation. When the rotating platform drives the wafer to rotate one circle, the image acquisition unit acquires all images of the edge of the wafer.

Images