A wafer alignment method and control system based on visual positioning

Abstract

The present invention provides a wafer alignment method and control system based on visual positioning, wherein a wafer is taken out of a jammer through a transport module and transported to a correction platform; a wafer is initially aligned through a first alignment member; a wafer is secondarily aligned through a second alignment member; a control command is sent to a plurality of servo motors; the servo motors are controlled to drive a plurality of alignment modules simultaneously to move the wafer to a reference position; the wafer is transported to an attachment platform through a transport module; an attachment head is driven to attach a UV film to the wafer; a cutter is used to perform profile cutting of the wafer; and the transport module is controlled to transport the wafer to the jammer. The present invention performs initial and secondary alignment of the wafer through the first alignment member and the second alignment member, can achieve high-precision alignment, can facilitate subsequent film pasting and film cutting, and can simultaneously drive a plurality of servo motors to move the wafer to a reference position, which can greatly improve the production efficiency of the wafer.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor chip manufacturing, and in particular to a wafer alignment method and control system based on vision positioning. Background Art

[0002] In semiconductor equipment, wafer is a basic material for manufacturing semiconductor chips. The surface needs to be treated with UV film, which can provide good protection for the wafer surface. Before filming, after the wafer is placed on the platform, the center of the wafer will deviate from the center of the platform, so it is necessary to determine the position of the wafer and align the wafer to ensure the accuracy of filming.

[0003] However, the wafer alignment device in the prior art has low precision, and the alignment process is complicated and time-consuming, resulting in low wafer production efficiency. Summary of the invention

[0004] The present invention aims to solve the problems in the above-mentioned prior art that the wafer alignment has low accuracy, the alignment process is complicated and time-consuming, resulting in low wafer production efficiency, and provides a wafer alignment method and control system based on visual positioning.

[0005] The present invention provides a wafer alignment method based on visual positioning, comprising the following steps:

[0006] The wafer is taken out from the jammer by a preset transport module and transported to a preset calibration platform;

[0007] Performing initial alignment on the wafer by using a preset first alignment member;

[0008] Performing secondary alignment on the wafer by using a preset second alignment member;

[0009] Send control commands to multiple preset servo motors;

[0010] Controlling the servo motor to simultaneously drive a plurality of preset alignment modules to move the wafer to a reference position;

[0011] The wafer is transported to a preset attaching platform by the transport module, and a preset attaching head is driven to attach a UV film to the wafer;

[0012] Profiling the wafer using a preset cutting knife;

[0013] The transport module is controlled to transport the wafer into the plug.

[0014] Furthermore, the wafer is provided with at least one notch for aligning with the first alignment member and the second alignment member.

[0015] Furthermore, the step of initially aligning the wafer by using a preset first alignment member includes:

[0016] Acquiring a contour image of the wafer through the first alignment member;

[0017] The contour image is subjected to image preprocessing by a plurality of preset processors.

[0018] Furthermore, the step of performing image preprocessing on the contour image by using a plurality of preset processors includes:

[0019] Visualizing the focus and brightness of the contour image and comparing it with a preset normal image;

[0020] adjusting the focus and the brightness to be the same as the normal image;

[0021] The contour image is sharpened.

[0022] Furthermore, after the step of sharpening the contour image, the following steps are included:

[0023] Performing preliminary correction on the contour image;

[0024] A secondary correction is performed on the contour image.

[0025] Furthermore, after the step of performing secondary correction on the contour image, the following steps are included:

[0026] Determining whether the contour image includes the gap;

[0027] If yes, controlling the second alignment member to perform secondary alignment;

[0028] If not, the displacement direction and movement amount of the first alignment member are calculated according to the coordinate data of the contour image until the contour image includes the gap.

[0029] Furthermore, the step of performing secondary alignment on the wafer by using a preset second alignment member includes:

[0030] Identifying location information of the notch;

[0031] The notch is aligned with a preset attachment reference point.

[0032] Furthermore, the step of calibrating the notch with a preset attachment reference point includes:

[0033] The correction amount and the rotation angle are calculated based on the position information and the attachment reference point.

[0034] Furthermore, the step of controlling the servo motor to simultaneously drive a plurality of preset alignment modules includes:

[0035] The alignment module is driven to displace the correction amount and rotate the rotation angle.

[0036] Furthermore, the step of performing profile cutting on the wafer by a preset cutting knife includes:

[0037] The cutter is controlled to cut into the notch and perform profile cutting on the wafer.

[0038] The present invention also provides a wafer alignment control system based on visual positioning, including a plug, a transport module, a correction platform, a first alignment component, a second alignment component, an attachment platform, an attachment head, a main controller, a visual controller, a display screen, multiple processors, a servo motor and an alignment module; the main controller is electrically connected to the first alignment component and the second alignment component; the processor is respectively communicated with the first alignment component and the second alignment component; the plug is arranged on one side of the transport module; the attachment head is located on one side of the attachment platform and is electrically connected to the main controller; the main controller is electrically connected to the display screen; the visual controller is electrically connected to the first alignment component and the second alignment component, and is used to control the first alignment component and the second alignment component; the alignment module is provided with an alignment sensor, and is electrically connected to the servo motor, and is used to detect the moving position of the alignment module.

[0039] The present invention provides a wafer alignment method and control system based on visual positioning, which has the following beneficial effects:

[0040] The wafer is initially and secondarily aligned by the first alignment member and the second alignment member, which can achieve high-precision alignment, facilitate the subsequent film lamination and film cutting, and simultaneously drive multiple servo motors to move the wafer to the reference position, which can greatly improve the wafer production efficiency. The wafer contour image can be adjusted in the case of insufficient light, strong light or strong reflection on the wafer surface, which can improve the contour image quality, and the contour image can be initially and secondarily corrected, thereby improving the accuracy of wafer alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the method steps of a wafer alignment method based on visual positioning in the present invention;

[0042] Figure 2 It is a structural block diagram of a wafer alignment control system based on visual positioning in the present invention;

[0043] Figure 3It is a three-dimensional schematic diagram of a wafer alignment control system based on vision positioning in one embodiment of the present invention.

[0044] Description of markings: jam 1, transport module 2, correction platform 3, first alignment component 4, second alignment component 5, attachment platform 6, attachment head 7, main controller 8, visual controller 9, display screen 10, processor 11, servo motor 12, alignment module 13, alignment sensor 14. DETAILED DESCRIPTION

[0045] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Reference Figure 1 , is a wafer alignment method based on visual positioning in one embodiment of the present invention, comprising:

[0048] S1, taking the wafer out of the jammer 1 through the preset transport module 2 and transporting it to the preset calibration platform 3;

[0049] S2, performing initial alignment on the wafer by using a preset first alignment member 4;

[0050] S3, performing secondary alignment on the wafer by using a preset second alignment member 5;

[0051] S4, sending control commands to a plurality of preset servo motors 12;

[0052] S5, controlling the servo motor 12 to simultaneously drive a plurality of preset alignment modules 13 to move the wafer to a reference position;

[0053] S6, transporting the wafer to the preset attaching platform 6 through the transport module 2, and driving the preset attaching head 7 to attach the UV film to the wafer;

[0054] S7, cutting the wafer into a film by using a preset cutting knife;

[0055] S8, controlling the transport module 2 to transport the wafer into the plug 1.

[0056] In the above steps, first, the main controller 8 controls the transport module 2 to remove the wafer from the jam 1, wherein the main controller 8 is a PLC, a programmable logic controller, and stores multiple control commands. Then, the visual controller 9 triggers the first alignment member 4 and the second alignment member 5 to run. In a specific embodiment, the first alignment member 4 and the second alignment member 5 are CCD cameras with 500W pixels. The first alignment member 4 and the second alignment member 5 respectively perform initial alignment and secondary alignment on the wafer, and then drive the alignment module 13 to move the wafer to the reference position. Perform secondary alignment on the basis of the initial alignment, which can reduce the alignment error and improve the accuracy of the wafer alignment. Then send a control command to multiple servo motors 12, and control the servo motors 12 to drive multiple alignment modules 13 at the same time to move the wafer to the reference position. Then, the wafer is transported to the attachment platform 6 through the transport module 2, and the attachment head 7 is driven to operate to attach the film to the wafer. Then, the wafer is profiled and cut by a cutter, that is, the film is cut according to the shape of the wafer. Finally, the transport module 2 is controlled to transport the wafer into the plug 1.

[0057] In one embodiment, the wafer is provided with at least one notch for alignment with the first alignment member 4 and the second alignment member 5 .

[0058] In a specific implementation, a fixed notch is pre-set on the outer edge of the wafer for high-precision calibration of the second alignment member 5 and can be used as a calibration point.

[0059] In one embodiment, the step of initially aligning the wafer by using the preset first alignment member 4 includes:

[0060] Acquire a contour image of the wafer through the first alignment member 4;

[0061] The contour image is subjected to image preprocessing by a plurality of preset processors 11 .

[0062] The step of performing image preprocessing on the contour image by using a plurality of preset processors 11 includes:

[0063] Visualize the focus and brightness of the contour image and compare it with the preset normal image;

[0064] Adjust the focus and brightness to the same as normal images;

[0065] Sharpen the contour image.

[0066] In the specific implementation, the contour image of the wafer is then preprocessed by multiple processors 11. The method of processing the contour image by multiple processors 11 at the same time can have a faster processing speed, and the contour image can be quickly processed into data, wherein the contour image includes a color image and a black and white image. In a specific embodiment, there are three processors 11, including two DSPs and one CPU; wherein the DSP is a Digital Signal Processor, i.e., a digital signal processor; the CPU is a Central Processing Unit, a central processing unit; multiple processors 11 process the contour image at the same time, which can have a faster processing speed. After the contour image is collected, the focus and brightness of the contour image are visualized, that is, the focus data and brightness data of the contour image are processed by the processor 11 and presented on the display screen 10, such as the brightness of 89 can be displayed on the display screen 10. Then, it is compared with the preset normal image. In a specific embodiment, the brightness of the normal image is 100, and the brightness of the contour image is 89. After the comparison, the difference is 11, and the brightness of the contour image is adjusted to the same as the normal image, i.e., adjusted to 100. In another specific embodiment, the focus of the contour image is located on the left side of the image center, while the focus of the normal image is located at the image center. After comparison, the focus of the contour image is adjusted to the center of the contour image, and the adjustment method may be to move the first alignment member 4. Then, the contour image is sharpened to make the contour image clearer for subsequent correction.

[0067] In one embodiment, after the step of sharpening the contour image, the following steps are included:

[0068] Perform preliminary correction on the contour image;

[0069] Perform secondary correction on the contour image.

[0070] In a specific implementation, after the contour image is sharpened, the contour image is initially corrected by the first correction unit. In a specific embodiment, the initial correction is lens distortion correction, that is, the image is enlarged or reduced to improve the problem of inconsistency between the center and the surroundings of the image caused by lens distortion and deformation, so that the image can be evenly displayed on the display screen 10. Then, a secondary correction is performed by the second correction unit, that is, the tilt of the image is corrected. When the image is tilted to the right, the image is corrected to the left to obtain a corrected image.

[0071] In one embodiment, after the step of performing secondary correction on the contour image, the following steps are included:

[0072] Determine whether the contour image contains a gap;

[0073] If yes, the second alignment member 5 is controlled to perform secondary alignment;

[0074] If not, the displacement direction and movement amount of the first alignment member 4 are calculated according to the coordinate data of the contour image until the contour image contains a gap.

[0075] In a specific implementation, after the contour image is corrected twice, the first alignment member 4 is used to determine whether the contour image of the wafer contains a notch, that is, the first alignment member 4 can be used to correct the notch feature to the field of view of the second alignment member 5. If the notch is within the field of view of the second alignment member 5, the wafer is corrected with high precision by the second alignment member 5. If the notch is not within the field of view of the second alignment member 5, the displacement direction and movement amount of the first alignment member 4 are calculated until the notch is within the field of view of the second alignment member 5.

[0076] Specifically, the center coordinates of the wafer contour image are located to the left of the preset reference point (0,0), and the position of the coordinate point is (-8,0). After calculating the difference between the two coordinate points, it is obtained that the first alignment member 4 is offset to the left, and the moving direction needs to be to the right, and the moving amount is 8, so the first alignment member 4 is controlled to move to the right and move 8 units. At this time, the wafer contour image is completely located on the display screen 10, and includes the gap.

[0077] In one embodiment, the step of performing secondary alignment on the wafer by using the preset second alignment member 5 includes:

[0078] Identify the location information of the gap;

[0079] Align the gap with the preset attachment reference point.

[0080] In one embodiment, the step of calibrating the notch with the preset attachment reference point includes:

[0081] The correction amount and rotation angle are calculated based on the position information and the attachment reference point.

[0082] The step of controlling the servo motor 12 to simultaneously drive a plurality of preset alignment modules 13 includes:

[0083] The alignment module 13 is driven to shift the correction amount and rotate the platform 3 to correct the angle.

[0084] In the specific implementation, the film-attaching platform is pre-set with an attachment base point. In the process of correcting the notch at the attachment base point, the correction amount and the rotation angle are first calculated according to the notch position information and the attachment base point, wherein the notch position information is the coordinates of the notch, and the attachment base point is the pre-entered coordinate point. Then the correction amount and the rotation angle between the two on the X-axis and Y-axis are calculated, and the calculation method can be to calculate the difference between the coordinates of the notch and the coordinates of the attachment base point. If the coordinates of the notch are (3,4) and the coordinates of the attachment base point are (5,5), the wafer is displaced by 2 on the X-axis and 1 on the Y-axis until the notch reaches the position of the coordinate point (5,5). In a specific embodiment, the calculated correction amount is 4, and the wafer is controlled to move four units so that the notch reaches the position of the attachment base point. In another specific embodiment, the angle between the notch and the attachment base point is 75°, and the wafer is rotated 75° so that the notch is corrected at the position of the attachment base point.

[0085] In one embodiment, the step of performing profile cutting on the wafer by a preset cutting knife includes:

[0086] The cutter is controlled to cut into the notch and perform profile cutting on the wafer.

[0087] In the specific implementation, after the notch and the attachment base point are corrected and the film is attached, the cutter is controlled to cut into the notch and perform contour cutting for the wafer. In a specific embodiment, the shape of the wafer is circular, so after the cutter cuts into the notch, it cuts around the edge of the wafer. At this time, the UV film is cut into a circle that is consistent with the size and shape of the wafer.

[0088] Reference Figure 2 and Figure 3 A wafer alignment control system based on visual positioning includes a plug 1, a transport module 2, a correction platform 3, a first alignment member 4, a second alignment member 5, an attachment platform 6, an attachment head 7, a main controller 8, a visual controller 9, a display screen 10, multiple processors 11, a servo motor 12 and an alignment module 13; the main controller 8 is electrically connected to the first alignment member 4 and the second alignment member 5; the processor 11 is respectively communicated with the first alignment member 4 and the second alignment member 5; the plug 1 is arranged on one side of the transport module 2; the attachment head 7 is located on one side of the attachment platform 6 and is electrically connected to the main controller 8; the main controller 8 is electrically connected to the display screen 10; the visual controller 9 is electrically connected to the first alignment member 4 and the second alignment member 5, and is used to control the first alignment member 4 and the second alignment member 5; the alignment module 13 is provided with an alignment sensor 14, which is electrically connected to the servo motor 12 and is used to detect the moving position of the alignment module 13.

[0089] In the specific implementation, the main controller 8 is a PLC, a programmable logic controller, and the main controller 8 is electrically connected to the visual controller 9 to control the operation of the visual controller 9. The first alignment member 4 and the second alignment member 5 are cameras, and the visual controller 9 is electrically connected to the first alignment member 4 and the second alignment member 5, and is used to control the first alignment member 4 and the second alignment member 5. On one side of the plug 1 handling module 2, the plug 1 is a multi-layer setting structure and is used to place multiple wafers. The handling module 2 is a three-axis manipulator that can transport the wafer in the directions of the X axis, Y axis and Z axis after taking the wafer. The processor 11 is electrically connected to the first alignment member 4 and the second alignment member 5 respectively, and can process the images taken by the first alignment member 4 and the second alignment member 5; the processor 11 includes a first processor 11, a second processor 11 and a third processor 11, the first processor 11 is a DSP, Digital Signal Processor, that is, a digital signal processor 11; the second processor 11 is a CPU; the third processor 11 is also a DSP, and the collected images are processed by multiple processors 11, which can achieve fast processing. The servo motor 12 is electrically connected to the alignment module 13 and is used to drive the alignment module 13 to move so that the wafer can be aligned. An alignment sensor is provided on one side of the alignment module 13. The alignment sensor is provided in the moving direction of the alignment module 13 and can detect the moving position of the alignment module 13 to obtain the moving distance of the wafer.

[0090] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media provided in this application and used in the embodiments may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0091] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0092] The above description is only a preferred embodiment 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 present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A wafer alignment method based on visual positioning, characterized in that: The following steps are involved: The wafer is taken out from the jammer by a preset transport module and transported to a preset calibration platform; Performing initial alignment on the wafer by using a preset first alignment member; Acquiring a contour image of the wafer through the first alignment member; Performing image preprocessing on the contour image through a plurality of preset processors; The step of performing image preprocessing on the contour image by using a plurality of preset processors includes: Visualizing the focus and brightness of the contour image and comparing it with a preset normal image; adjusting the focus and the brightness to be the same as the normal image; Performing a sharpening process on the contour image; After the step of sharpening the contour image, the method further comprises: Performing preliminary correction on the contour image; Performing secondary correction on the contour image; Performing secondary alignment on the wafer by using a preset second alignment member; Send control commands to multiple preset servo motors; Controlling the servo motor to simultaneously drive a plurality of preset alignment modules to move the wafer to a reference position; The wafer is transported to a preset attaching platform by the transport module, and a preset attaching head is driven to attach a UV film to the wafer; Profiling the wafer using a preset cutting knife; The transport module is controlled to transport the wafer into the plug.

2. The wafer alignment method based on visual positioning according to claim 1, characterized in that: The wafer is provided with at least one notch for aligning with the first alignment member and the second alignment member.

3. The wafer alignment method based on visual positioning according to claim 2, characterized in that: After the step of performing secondary correction on the contour image, the method further comprises: Determining whether the contour image includes the gap; If yes, controlling the second alignment member to perform secondary alignment; If not, the displacement direction and movement amount of the first alignment member are calculated according to the coordinate data of the contour image until the contour image includes the gap.

4. The wafer alignment method based on visual positioning according to claim 2, characterized in that: The step of performing secondary alignment on the wafer by using a preset second alignment member includes: Identifying location information of the notch; The notch is aligned with a preset attachment reference point.

5. The wafer alignment method based on visual positioning according to claim 4, characterized in that: The step of calibrating the notch with the preset attachment reference point includes: The correction amount and the rotation angle are calculated based on the position information and the attachment reference point.

6. The wafer alignment method based on visual positioning according to claim 5, characterized in that: The step of controlling the servo motor to simultaneously drive a plurality of preset alignment modules includes: The alignment module is driven to displace the correction amount and rotate the rotation angle.

7. The wafer alignment method based on visual positioning according to claim 2, characterized in that: The step of performing profile cutting on the wafer by a preset cutting knife comprises: The cutter is controlled to cut into the notch and perform profile cutting on the wafer.

8. A control system for a wafer alignment method based on vision positioning according to any one of claims 1 to 7, characterized in that: It includes a jammer, a transport module, a correction platform, a first alignment member, a second alignment member, an attachment platform, an attachment head, a main controller, a visual controller, a display screen, multiple processors, a servo motor and an alignment module; The main controller is electrically connected to the first alignment member and the second alignment member; The processor is respectively connected to the first alignment member and the second alignment member for communication; The plug is arranged on one side of the transport module; The attachment head is located at one side of the attachment platform and is electrically connected to the main controller; The main controller is electrically connected to the display screen; The visual controller is electrically connected to the first alignment member and the second alignment member, and is used to control the first alignment member and the second alignment member; The alignment module is provided with an alignment sensor, which is electrically connected to the servo motor and is used to detect the moving position of the alignment module.

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