Wafer pose recognition system and image acquisition device and image acquisition method thereof

Abstract

The invention relates to a wafer pose recognition system and an image acquisition device and an image acquisition method thereof, the wafer pose recognition system comprises a support structure for supporting a wafer to be recognized and the image acquisition device arranged above the wafer to be recognized, and an image sensing module is arranged in the image acquisition device. A fisheye lens group or a negative lens is adopted to enlarge the visual field width of an image sensor, so that the image sensing module can obtain complete edge image information of a wafer in one-time imaging, the positioning efficiency is improved, an annular first light shielding plate and a circular second light shielding plate are arranged on an optical path of the lens to form an annular visual field in a matched mode, and the positioning precision is improved. The edge blurred part image and the middle too bright part image are physically excluded, the imaging quality in the annular view is improved, the clear and complete wafer positioning edge image can be obtained, the contour recognition precision during image recognition is improved, and the positioning accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and particularly to a wafer pose recognition system, an image acquisition device thereof, and an image acquisition method thereof. Background Art

[0002] In the field of semiconductor manufacturing, the transfer of wafers has evolved from manual to fully automated. Therefore, accurate wafer pose judgment is an important link to ensure accurate wafer transfer. Currently, when recognizing the wafer pose through vision, an image sensing module is usually used to take pictures of the wafer from above. Due to the limitations of the effective field of view and recognition accuracy, during positioning shooting, a single shooting generally only performs local shooting and recognition on a certain edge of the wafer, and then multiple shootings are performed on different edges of the wafer respectively to obtain sufficient data for comprehensive calculation to obtain the relative position of the wafer relative to the positioning point. Such a pose recognition method requires multiple shootings, with relatively low efficiency and low positioning accuracy.

[0003] The statements herein only provide background art related to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0004] The purpose of the present invention is to provide a wafer pose recognition system, an image acquisition device thereof, and an image acquisition method thereof, which expand the imaging field of view and improve the positioning efficiency, imaging quality, recognition accuracy, and positioning accuracy.

[0005] To achieve the above purpose, the present invention provides an image acquisition device for acquiring a surface image of a wafer to be recognized, comprising:

[0006] A housing;

[0007] An image sensing module fixedly arranged in the housing;

[0008] A first light-shielding plate, the first light-shielding plate being an annular plate;

[0009] A second light-shielding plate, the second light-shielding plate being a circular plate, the diameter of the second light-shielding plate being smaller than the diameter of the inner ring of the first light-shielding plate, the first light-shielding plate and the second light-shielding plate forming an annular window, so that the image sensing module has a first annular field of view;

[0010] At least one lens module fixedly arranged on the housing, the lens module being located between the image sensing module and the wafer to be recognized in the optical path direction, at least part of the lens module being located within the annular window, and light from the surface of the wafer to be recognized reaching the image sensing module through the lens, so that the image sensing module has a second annular field of view;

[0011] The second annular field of view is larger than the first annular field of view.

[0012] The image sensing module includes a CCD sensor or a CMOS sensor.

[0013] Optionally, the lens module includes a fish-eye lens group.

[0014] Optionally, the lens module includes an annular lens, the inner diameter of the annular lens is smaller than the diameter of the second light shield; the annular lens is a negative lens arranged in a ring shape.

[0015] The distance between the first light shield and the image sensing module is smaller than the distance between the second light shield and the image sensing module, the annular lens is inclined, and the normal of the inclined surface of the annular lens faces the image sensing module.

[0016] Optionally, the lens module uses a meniscus negative lens.

[0017] The present invention also provides a wafer pose recognition system, comprising:

[0018] A support structure for placing and supporting the wafer to be recognized, the support structure includes a preset support position;

[0019] The image acquisition device, the image acquisition device is located above the support structure, and the orthographic projection of the image acquisition device on the preset support position is located at the center position of the preset support position;

[0020] A support frame for installing the image acquisition module.

[0021] The height of the support frame is adjustable, and the support frame drives the image acquisition module to move up and down in the vertical direction.

[0022] The present invention also provides an image acquisition method using the wafer pose recognition system, by setting the image acquisition device above the support structure through the support frame, and making the orthographic projection of the image acquisition device on the preset support position of the support structure be located at the center position of the preset support position, and the image acquisition device acquires a complete edge image of the wafer to be recognized within the second annular field of view.

[0023] Adjust the distance between the image acquisition device and the wafer to be recognized by adjusting the height of the support frame, so that the second annular field of view of the image acquisition device completely covers the entire edge of the wafer to be recognized. The present invention uses a fish-eye lens group or a negative lens to effectively expand the field of view width of the image sensing module. On the premise of meeting the effective viewing distance, the image sensing module can obtain the complete edge image information of the wafer in one imaging, improving the positioning efficiency. The present invention sets an annular first light-shielding plate and a circular second light-shielding plate on the optical path of the lens in the image acquisition device. The annular first light-shielding plate is arranged in the edge area of the optical path and can block the edge distortion and the diffuse edge of the lens. The circular second light-shielding plate is arranged in the central area of the optical path and can block the imaging area with the highest light intensity. By the cooperation of the first light-shielding plate and the second light-shielding plate, an annular field of view is formed, and the images of the edge-blurred part and the overly bright part in the middle can be physically excluded, making the inside of the annular field of view clearer, improving the imaging quality inside the annular field of view, facilitating the acquisition of a clear and complete image of the wafer positioning edge, increasing the recognition accuracy of the contour during image recognition, and improving the positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. is a schematic structural diagram of a wafer pose recognition system provided by the present invention.

[0025] Figure 2 is Figure 1 the top view of.

[0026] Figure 3 is Figure 1 the schematic cross-sectional structure diagram taken along the line A-A in, showing an image acquisition device provided in an embodiment of the present invention.

[0027] Figure 4 is Figure 3 the schematic diagram of the first annular field of view and the second annular field of view in.

[0028] Figure 5 FIG. is the schematic diagram of the second annular field of view of the image acquisition device.

[0029] Figure 6 is Figure 1 the schematic cross-sectional structure diagram taken along the line A-A in, showing an image acquisition device provided in another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following specifically describes the preferred embodiments of the present invention according to Figures 1 to 6 .

[0031] As shown in Figure 1 and Figure 2As shown in the figure, the present invention provides a wafer pose recognition system, which includes a support structure 2 for placing and supporting the wafer 1 to be recognized and an image acquisition device 3 arranged above the wafer 1 to be recognized. The image acquisition device 3 is used to acquire the surface image of the wafer 1 to be recognized so as to realize the pose recognition of the wafer 1 to be recognized. A highly adjustable support frame 4 is used to install the image acquisition device 3. By adjusting the height of the support frame 4, the support frame 3 drives the image acquisition device 3 to lift in the vertical direction, thereby adjusting the distance between the image acquisition device 3 and the wafer 1 to be recognized.

[0032] As Figure 3 shown, in an embodiment of the present invention, the image acquisition device 3 includes a housing 301 and an image sensing module 302 fixedly arranged in the housing 301. The image sensing module 302 includes an image sensor and a corresponding circuit module. The image sensor uses a CCD sensor or a CMOS sensor and is used to acquire the surface image of the wafer 1 to be recognized. The image acquisition device 3 has an annular first light-shielding plate 303 and a circular second light-shielding plate 304. In this embodiment, a transparent mounting plate 306 is used to fixedly mount the first light-shielding plate 303 and the second light-shielding plate 304 to the housing 301. The transparent mounting plate 306 can be fixed to the housing 301 through a connecting piece, a fastening piece, an adhesive, etc., so that the transparent mounting plate 306 is located below the image sensing module 302. The first light-shielding plate 303 and the second light-shielding plate 304 can also be fixed to the transparent mounting plate 306 through a connecting piece, a fastening piece, an adhesive, etc. The diameter of the inner ring of the first light-shielding plate 303 is greater than the diameter of the second light-shielding plate 304, so that the first light-shielding plate 303 is arranged on the periphery of the second light-shielding plate 304 and the first light-shielding plate 303 and the second light-shielding plate 304 are concentrically arranged. Then the first light-shielding plate 303 and the second light-shielding plate 304 jointly form an annular window 307, and the width of the annular window 307 along the radial direction is the same. Because the transparent mounting plate 306 is used, the annular window 307 can transmit light without obstruction. The annular window 307 enables the image sensing module 302 to have a first annular field of view 310 (as Figure 4 shown). The image acquisition device 3 further includes a meniscus negative lens 305 fixedly arranged on the housing 301. Similarly, the meniscus negative lens 305 is fixed to the housing 301 through a connecting piece, a fastening piece, an adhesive, etc., so that the meniscus negative lens 305 is located below the transparent mounting plate 306. The meniscus negative lens 305 is located between the image sensing module 302 and the wafer 1 to be recognized in the optical path direction, and the meniscus negative lens 305 covers the entire annular window 307, as Figure 4As shown, the light from the surface of the wafer 1 to be recognized passes through the meniscus negative lens 305 and then through the annular window 307, and finally reaches the image sensing module 302. The meniscus negative lens 305 enlarges the range of the first annular field of view formed by the annular window 307, so that the image sensing module 302 has an enlarged second annular field of view 309.

[0033] As Figure 1 and Figure 2 shown, when using the image acquisition device 3 to perform image acquisition and pose recognition on the wafer 1 to be recognized placed on the support structure 2, the support structure 2 has a preset support position (not shown in the figure). The preset support position can be set as a shallow groove or other positioning structures. The shape of the preset support position matches that of the wafer 1 to be recognized, and can make the wafer 1 to be recognized placed exactly on the preset support position, so as to ensure that the position of the wafer 1 to be recognized placed on the support structure 2 remains fixed. Use the support frame 4 to set the image acquisition device 3 directly above the wafer 1 to be recognized (i.e., the preset support position), and make the orthographic projection of the image acquisition device 3 on the surface of the wafer 1 to be recognized located at the center position of the surface of the wafer 1 to be recognized (as Figure 2 shown), so that as Figure 5 shown, the edge of the wafer 1 to be recognized can be exactly located within the second annular field of view 309 of the image acquisition device 3. Only the light located within the second annular field of view 309 can pass through the meniscus negative lens 305 and reach the image sensing module 302, while the light located outside the second annular field of view 309 will be blocked by the first light shielding plate 303 and cannot reach the image sensing module 302, so as to block the edge distortion and the diffuse edge of the meniscus negative lens 305. Similarly, the light located within the inner circle of the second annular field of view 309 will be blocked by the second light shielding plate 304 and also cannot reach the image sensing module 302, so as to block the imaging area with the highest light intensity, which is beneficial to highlighting the imaging quality within the annular field of view. Further, adjust the height of the support frame 4 to adjust the distance between the image acquisition device 3 and the wafer 1 to be recognized. When there is a suitable distance between the meniscus negative lens 305 in the image acquisition device 3 and the wafer 1 to be recognized, the second annular field of view 309 of the image acquisition device 3 can completely cover the entire edge area of the wafer 1 to be recognized, so that the image sensing module 302 in the image acquisition device 3 can collect the complete edge image of the wafer 1 to be recognized at one time through the second annular field of view 309.

[0034] The present invention uses a meniscus negative lens to effectively expand the field of view width of the image sensing module. On the premise of meeting the effective viewing distance, the image sensing module can obtain the complete edge image information of the wafer in a single imaging, improving the positioning efficiency. In the present invention, an annular first light-shielding plate and a circular second light-shielding plate are arranged on the optical path of the meniscus negative lens in the image acquisition device. The annular first light-shielding plate is arranged in the edge area of the optical path and can block the edge distortion and the diffused edge of the meniscus negative lens. The circular second light-shielding plate is arranged in the central area of the optical path and can block the imaging area with the highest light intensity. By the cooperation of the first light-shielding plate and the second light-shielding plate, an annular field of view is formed, which can physically exclude the images of the blurred edge part and the overly bright middle part, making the inside of the annular field of view clearer, improving the imaging quality inside the annular field of view, facilitating the acquisition of a clear and complete image of the wafer positioning edge, increasing the recognition accuracy of the contour during image recognition, and improving the positioning accuracy.

[0035] In another embodiment of the present invention, a fish-eye lens array group (not shown in the figure) can also be used for the lens in the image acquisition device 3, and the structures of other components in the image acquisition device 3 remain unchanged. The fish-eye lens array group can also diverge light, increasing the range of the first annular field of view formed by the annular window 307, so that the image sensing module 302 has an enlarged second annular field of view.

[0036] The present invention uses a fish-eye lens to effectively expand the field of view width of the image sensing module. On the premise of meeting the effective viewing distance, the image sensing module can obtain the complete edge image information of the wafer in a single imaging, improving the positioning efficiency. In the present invention, an annular first light-shielding plate and a circular second light-shielding plate are arranged on the optical path of the fish-eye lens in the image acquisition device. The annular first light-shielding plate is arranged in the edge area of the optical path and can block the edge distortion and the diffused edge of the fish-eye lens. The circular second light-shielding plate is arranged in the central area of the optical path and can block the imaging area with the highest light intensity. By the cooperation of the first light-shielding plate and the second light-shielding plate, an annular field of view is formed, which can physically exclude the images of the blurred edge part and the overly bright middle part, making the inside of the annular field of view clearer, improving the imaging quality inside the annular field of view, facilitating the acquisition of a clear and complete image of the wafer positioning edge, increasing the recognition accuracy of the contour during image recognition, and improving the positioning accuracy.

[0037] Such as Figure 6As shown, in another embodiment of the present invention, the lens in the image acquisition device 3 is an annular lens 308. The annular lens 308 can be an annular negative lens or a combination of negative lenses arranged in a ring shape. The annular lens 308 is fixed to the housing 301 by a connecting piece, a fastening piece, an adhesive, etc. The annular lens 308 is located between the image sensing module 302 and the wafer 1 to be recognized in the optical path direction. The annular lens 308 is inclined, and the normal line 311 of the inclined surface of the annular lens 308 faces the image sensing module 302. The annular lens 308 has an inclination angle, which can make its image area larger, equivalent to the image area when using a fisheye lens. The setting position of the first light shielding plate 303 remains unchanged. In addition to using a transparent mounting plate 306 as shown in Figure 3 to fix the first light shielding plate 303, the first light shielding plate 303 can also be directly fixed and mounted to the housing 301 by a connecting piece, a fastening piece, an adhesive, etc. The second light shielding plate 304 can also be arranged on the transparent mounting plate 306 in the manner shown in Figure 3 . In this embodiment, the diameter of the second light shielding plate 304 is larger than the inner diameter of the annular lens 308, so the second light shielding plate 304 can be fixed on the annular lens 308 by an adhesive (usually UV glue). Correspondingly, the distance between the second light shielding plate 304 and the image sensing module 302 is greater than the distance between the first light shielding plate 303 and the image sensing module 302. The first light shielding plate 303 and the second light shielding plate 304 still need to be concentrically arranged, so the first light shielding plate 303 and the second light shielding plate 304 together form an annular window, and the annular window gives the image sensing module 302 a first annular field of view. The annular lens 308 covers the entire annular window. The light from the surface of the wafer 1 to be recognized passes through the annular lens 308 and then through the annular window, and finally reaches the image sensing module 302. The annular lens 308 increases the range of the first annular field of view, so that the image sensing module 302 has an enlarged second annular field of view.

[0038] As shown in Figure 1 and Figure 2 , when using the image acquisition device 3 to perform image acquisition and pose recognition on the wafer 1 to be recognized placed on the support structure 2, the image acquisition device 3 is arranged directly above the wafer 1 to be recognized by using the support frame 4, and the orthographic projection of the image acquisition device 3 on the surface of the wafer 1 to be recognized is located at the center position of the surface of the wafer 1 to be recognized (as shown in Figure 2 ), so that as shown in Figure 5As shown, the edge of the wafer 1 to be recognized can be exactly located within the second annular field of view 309 of the image acquisition device 3. Only the light within the second annular field of view 309 can pass through the annular lens 308 and reach the image sensing module 302, while the light outside the second annular field of view 309 will be blocked by the first light shield 303 and cannot reach the image sensing module 302, thereby blocking the edge distortion and the diffuse edge of the annular lens 308. Similarly, the light within the inner circle of the second annular field of view 309 will be blocked by the second light shield 304 and also cannot reach the image sensing module 302, thus blocking the imaging area with the highest light intensity and being beneficial to highlighting the imaging quality within the annular field of view. Further, by adjusting the height of the support frame 4, the distance between the image acquisition device 3 and the wafer 1 to be recognized is adjusted. When there is a suitable distance between the annular lens 308 in the image acquisition device 3 and the wafer 1 to be recognized, the second annular field of view 309 of the image acquisition device 3 can completely cover the entire edge area of the wafer 1 to be recognized, enabling the image sensing module 302 in the image acquisition device 3 to collect the complete edge image of the wafer 1 to be recognized at one time through the second annular field of view 309.

[0039] The present invention uses a negative lens to effectively expand the field of view width of the image sensing module. On the premise of meeting the effective viewing distance, the image sensing module can obtain the complete edge image information of the wafer in one imaging, improving the positioning efficiency. The present invention provides an annular first light shield and a circular second light shield on the optical path of the annular negative lens in the image acquisition device. The annular first light shield is arranged in the edge area of the optical path and can block the edge distortion and the diffuse edge of the annular negative lens. The circular second light shield is arranged in the central area of the optical path and can block the imaging area with the highest light intensity. By the cooperation of the first light shield and the second light shield, an annular field of view is formed, which can physically exclude the edge-blurred partial image and the overly bright partial image in the middle, making the inside of the annular field of view clearer, improving the imaging quality within the annular field of view, being beneficial to obtaining a clear and complete image of the positioning edge of the wafer, increasing the recognition accuracy of the contour during image recognition, and improving the positioning accuracy.

[0040] It should be noted that in the embodiments of the present invention, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0041] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation to the present invention. After those skilled in the art have read the above content, various modifications and alternatives to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. An image acquisition device for obtaining a surface image of a wafer to be recognized, characterized in that, Comprising: A housing; An image sensing module fixedly disposed within the housing; A first light shield, the first light shield being an annular plate; A second light shield, the second light shield being a circular plate, the diameter of the second light shield being smaller than the diameter of the inner ring of the first light shield, the first light shield and the second light shield forming an annular window, so that the image sensing module has a first annular field of view; At least one lens module fixedly disposed on the housing, the lens module being located between the image sensing module and the wafer to be recognized in the optical path direction, at least a part of the lens module being located within the annular window, light from the surface of the wafer to be recognized passing through the lens to reach the image sensing module, so that the image sensing module has a second annular field of view; The second annular field of view is larger than the first annular field of view.

2. The image acquisition device according to claim 1, characterized in that, The image sensing module includes a CCD sensor or a CMOS sensor.

3. The image acquisition device according to claim 1, characterized in that, The lens module includes a fisheye lens group.

4. The image acquisition device according to claim 1, wherein The lens module includes an annular lens, the inner diameter of the annular lens being smaller than the diameter of the second light shield; the annular lens is a negative lens arranged in a ring shape.

5. The image acquisition device according to claim 4, wherein The distance between the first light shield and the image sensing module is smaller than the distance between the second light shield and the image sensing module, the annular lens is inclined, and the normal of the inclined surface of the annular lens faces the image sensing module.

6. The image acquisition device according to claim 1, characterized in that, The lens module includes a meniscus negative lens.

7. A wafer pose recognition system, characterized in that, Comprising: A support structure for placing and supporting the wafer to be recognized, the support structure including a preset support position; The image acquisition device according to any one of claims 1-6, the image acquisition device being located above the support structure, and the orthographic projection of the image acquisition device at the preset support position being located at the central position of the preset support position; A support frame for mounting the image acquisition module.

8. The wafer pose recognition system according to claim 7, wherein The height of the support frame is adjustable, and the support frame drives the image acquisition module to move up and down in the vertical direction.

9. An image acquisition method using the wafer pose recognition system as described in claim 8, characterized in that, The image acquisition device is arranged above the support structure through the support frame, and the orthographic projection of the image acquisition device at the preset support position of the support structure is located at the central position of the preset support position, and the image acquisition device acquires a complete edge image of the wafer to be recognized located within the second annular field of view.

10. The image acquisition method according to claim 9, wherein The distance between the image acquisition device and the wafer to be recognized is adjusted by adjusting the height of the support frame, so that the second annular field of view of the image acquisition device completely covers the complete edge of the wafer to be recognized.

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