Square wafer pre-alignment method, system, electronic device and storage medium

Abstract

The present application provides a square wafer pre-alignment method, system, electronic device, and storage medium, the method comprising: obtaining a target image corresponding to a square wafer to be aligned; determining the vertex positions of the four vertices of the square wafer to be aligned and the angle information of the four sides based on the target image; determining a first rotation angle based on the angle information of the four sides; controlling a rotating platform to rotate according to the first rotation angle; determining the center point position of the square wafer to be aligned after rotation and the offset distance between the center point position after rotation and the target position based on the first rotation angle and the vertex positions of the four vertices; controlling the movement of a mobile platform based on the offset distance to move the square wafer to be aligned to the target position in the measurement coordinate system to complete position alignment. By adopting the above-mentioned square wafer pre-alignment method, system, electronic device, and storage medium, the problem of being unable to pre-align square wafers is solved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a square wafer pre-alignment method, system, electronic device and storage medium. Background Art

[0002] With the development of semiconductor processing technology, the requirements for wafer alignment accuracy during processing are becoming increasingly higher. In order to shorten the time for precise alignment, it is necessary to add a pre-alignment process during the wafer transfer process before precise alignment to ensure that the wafer can be accurately aligned in a shorter time.

[0003] A wafer refers to a silicon chip used to manufacture silicon semiconductor integrated circuits. Most wafers are round in shape, but in some special fields, square wafers are also needed. Currently, there is a lack of pre-alignment solutions for square wafers in wafer transmission systems. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a square wafer pre-alignment method, system, electronic device and storage medium, which solve the problem of being unable to pre-align square wafers.

[0005] In a first aspect, an embodiment of the present application provides a square wafer pre-alignment method, comprising:

[0006] receiving a feedback signal indicating that the square wafer to be aligned has been placed in the target wafer slot, and obtaining a target image corresponding to the square wafer to be aligned;

[0007] Based on the target image, determining the vertex positions of the four vertices of the square wafer to be aligned and the angle information of the four sides;

[0008] Determine a first rotation angle based on the angle information of the four sides;

[0009] Controlling the rotating platform to rotate according to a first rotation angle so that the square wafer to be aligned is placed at a target angle with respect to the abscissa axis in the measurement coordinate system;

[0010] Determining a center point position of the square wafer to be aligned after rotation and an offset distance between the center point position after rotation and a target position based on the first rotation angle and the vertex positions of the four vertices;

[0011] The movement of the moving platform is controlled based on the offset distance so that the square wafer to be aligned is moved to the target position in the measurement coordinate system to complete the position alignment.

[0012] Optionally, based on the target image, the vertex positions of the four vertices of the square wafer to be aligned and the angle information of the four sides are determined, including: obtaining the grayscale value of each pixel point in the target image; for each pixel point, determining the difference between the grayscale value of multiple adjacent pixel points adjacent to the pixel point and the pixel point; determining the difference between two adjacent pixel points as the gradient of the two adjacent pixel points; determining the pixel points corresponding to multiple gradients greater than the gradient threshold as multiple edge pixel points of the square wafer to be aligned; based on the multiple edge pixel points of the square wafer to be aligned, determining the vertex positions of the four vertices of the square wafer to be aligned and the angle information of the four sides.

[0013] Optionally, based on multiple edge pixel points of the square wafer to be aligned, the vertex positions of the four vertices of the square wafer to be aligned and the angle information of the four sides are determined, including: connecting the multiple edge pixel points through linear fitting to determine the position information of the square wafer to be aligned in the image coordinate system; based on the conversion relationship between the image coordinate system and the measurement coordinate system, converting the position information of the square wafer to be aligned in the image coordinate system into the position information in the measurement coordinate system, the position information in the measurement coordinate system includes the vertex positions of the four vertices and the positions of the four sides; based on the positions of the four sides, determining the angle information of the four sides, the angle information of the four sides includes a first angle, a second angle, a third angle and a fourth angle, the first angle, the second angle, the third angle and the fourth angle are the angles between the first side, the second side, the third side and the fourth side of the square wafer to be aligned and the horizontal positive direction of the measurement coordinate system, respectively. In a clockwise direction, the four sides of the square wafer to be aligned are the first side, the fourth side, the second side and the third side respectively.

[0014] Optionally, based on the angle information of the four sides, the first rotation angle is determined, including: determining the average value of the first angle and the second angle as the horizontal angle; determining the average value of the third angle and the fourth angle as the vertical angle; determining the difference between the vertical angle and 90° as the rotated vertical angle; determining the average value of the horizontal angle and the rotated vertical angle as the reference angle; and determining the difference between the reference angle and the target angle as the first rotation angle.

[0015] Optionally, based on the first rotation angle and the vertex positions of the four vertices, the center point position of the square wafer to be aligned after rotation and the offset distance between the center point position after rotation and the target position are determined, including: determining the two diagonal lines of the square wafer to be aligned based on the vertex positions of the four vertices; determining the intersection position of the two diagonal lines as the center point position of the square wafer to be aligned before rotation; determining the center point position of the square wafer to be aligned after rotation based on the first rotation angle and the center point position before rotation; and determining the offset distance between the center point position after rotation and the target position.

[0016] Optionally, before receiving a feedback signal indicating that the square wafer to be aligned has been placed in the target wafer slot and obtaining a target image corresponding to the square wafer to be aligned, the method also includes: receiving external data, the external data including wafer information of the square wafer to be aligned; and determining a target wafer slot corresponding to the type of the square wafer to be aligned based on the wafer information.

[0017] Optionally, after determining the target wafer slot corresponding to the type of square wafer to be aligned based on the wafer information, the method also includes: determining a second rotation angle based on the position of the target wafer slot on the rotating platform and the position where the external robot places the wafer; controlling the rotating platform to rotate according to the second rotation angle so that the position of the target wafer slot after rotation corresponds to the position where the external robot places the wafer.

[0018] In a second aspect, an embodiment of the present application further provides a square wafer pre-alignment system, the system comprising:

[0019] A control unit, a camera, and a mobile platform, wherein the mobile platform includes a rotating platform on which multiple wafer slots of different types are arranged;

[0020] The control unit performs the steps of the square wafer alignment method as described above;

[0021] The control unit is connected to the camera and the mobile platform respectively to control the camera and the mobile platform;

[0022] The camera is located above the moving platform to take pictures of the square wafer to be aligned on the moving platform.

[0023] In a third aspect, an embodiment of the present application further provides an electronic device comprising: a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor and the memory communicate through the bus, and when the machine-readable instructions are executed by the processor, the steps of the square wafer pre-alignment method as described above are performed.

[0024] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, which executes the steps of the square wafer pre-alignment method as described above when the computer program is executed by a processor.

[0025] The embodiments of the present application bring the following beneficial effects:

[0026] The embodiments of the present application provide a square wafer pre-alignment method, system, electronic device and storage medium, which can obtain the vertex positions of the four vertices of the square wafer and the angle information of the four sides through the target image of the square wafer, determine the pre-alignment rotation angle and offset distance based on the vertex positions of the four vertices and the angle information of the four sides, and move the square wafer to be aligned to the target position by rotating it first and then moving it, thereby solving the problem of being unable to pre-align the square wafer.

[0027] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A flow chart of a square wafer pre-alignment method provided in an embodiment of the present application is shown;

[0030] Figure 2 A schematic diagram of a mobile platform provided in an embodiment of the present application is shown;

[0031] Figure 3 A schematic diagram showing the angle information of the four sides of a square wafer to be aligned provided in an embodiment of the present application;

[0032] Figure 4 A schematic structural diagram of a square wafer pre-alignment system provided in an embodiment of the present application is shown;

[0033] Figure 5 A schematic diagram showing the software architecture provided by an embodiment of the present application;

[0034] Figure 6 A schematic structural diagram of an electronic device provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for which protection is claimed, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, each other embodiment obtained by those skilled in the art without making creative work falls within the scope of protection of the present application.

[0036] It is worth noting that before this application was proposed, with the development of semiconductor processing technology, the requirements for the accuracy of wafer alignment during the processing process became increasingly higher. In order to shorten the time for precise alignment, it is necessary to add a pre-alignment process during the wafer transfer process before precise alignment to ensure that the precise alignment of the wafer is completed in a shorter time. Wafer refers to the silicon wafer used in the manufacture of silicon semiconductor integrated circuits. Its shape is mostly round, but in some special fields, square wafers are also needed. At present, there is a lack of pre-alignment solutions for square wafers in wafer transfer systems.

[0037] Based on this, an embodiment of the present application provides a square wafer pre-alignment method to complete the pre-alignment of a square wafer.

[0038] It should be noted that the square wafer pre-alignment method can be applied to the control unit of a square wafer pre-alignment system to achieve position pre-alignment of the square wafer to be aligned. The square wafer pre-alignment system includes a control unit, a camera, and a mobile platform, wherein the mobile platform is provided with a rotating platform.

[0039] See also Figure 1 , Figure 1 This is a flow chart of a square wafer pre-alignment method provided in an embodiment of the present application. Figure 1 As shown, the square wafer pre-alignment method provided in the embodiment of the present application includes:

[0040] Step S101 : receiving a feedback signal indicating that the square wafer to be aligned has been placed in the target wafer slot, and acquiring a target image corresponding to the square wafer to be aligned.

[0041] In this step, the square wafer to be aligned may refer to a pre-aligned object, and the pre-aligned object is a square wafer, wherein the square wafer includes multiple wafer types, and square wafers of different wafer types correspond to different sizes.

[0042] Illustratively, the square wafer may be a square wafer or a rectangular wafer.

[0043] The target wafer slot may refer to a wafer slot corresponding to the wafer type of the square wafer to be aligned. The target wafer slot is used to hold the square wafer to be aligned. The target wafer slot is selected from a plurality of different types of wafer slots disposed on the rotating platform.

[0044] Refer to the following Figure 2 Let's introduce the position of the wafer slots on the rotating platform.

[0045] Figure 2 A schematic diagram of a mobile platform provided in an embodiment of the present application is shown.

[0046] like Figure 2 As shown, a rotating platform 202 is provided on a mobile platform 201. The rotating platform 202 rotates around a rotation center 203. A first-type wafer slot 204, a second-type wafer slot 205, a third-type wafer slot 206, and a fourth-type wafer slot 207 are located on the rotating platform 202. Point 208 is the target point for an external robot to place a wafer. The first-type wafer slot 204, the second-type wafer slot 205, the third-type wafer slot 206, and the fourth-type wafer slot 207 are all wafer slots of different sizes.

[0047] In an embodiment of the present application, when an external robot places a wafer into a wafer slot, it sends a feedback signal to the control unit. Upon receiving the feedback signal indicating that the square wafer to be aligned has been placed into the target wafer slot, the control unit acquires a target image corresponding to the square wafer to be aligned. Alternatively, a visual inspection method can be used to determine whether the wafer has been placed in the wafer slot by detecting the rate of change in light intensity before and after receiving the square wafer to be aligned.

[0048] In an optional embodiment, before executing step S101, the method further includes: receiving external data, the external data including wafer information of the square wafer to be aligned; and determining a target wafer slot corresponding to the type of the square wafer to be aligned based on the wafer information.

[0049] Here, the external data may refer to data obtained by a system other than the square wafer pre-alignment system, and the external data is used to determine wafer information of the square wafer to be aligned. The external data includes but is not limited to the wafer information of the square wafer to be aligned.

[0050] The wafer information may refer to identification information of the square wafer to be aligned, and the wafer information is used to determine the wafer type of the square wafer to be aligned.

[0051] Illustratively, the identification information may be size information of the square wafer to be aligned, or may be a type identification of the square wafer to be aligned.

[0052] In an embodiment of the present application, after receiving external data, wafer information of the square wafer to be aligned is obtained from the external data, and the size of the square wafer to be aligned is determined based on the wafer information, and then a slot corresponding to the size of the square wafer to be aligned is selected from multiple different types of wafer slots as the target wafer slot.

[0053] In an optional embodiment, after determining the target wafer slot corresponding to the type of square wafer to be aligned based on the wafer information, the method also includes: determining a second rotation angle based on the position of the target wafer slot on the rotating platform and the position where the external robot places the wafer; controlling the rotating platform to rotate according to the second rotation angle so that the position of the target wafer slot after rotation corresponds to the position where the external robot places the wafer.

[0054] Here, with Figure 2 For example, assuming that the third type wafer slot 206 is the target wafer slot, and the position where the external manipulator places the wafer is point 208, it is necessary to rotate the third type wafer slot 206 to the left by a certain angle so that the third type wafer slot 206 moves to the position corresponding to point 208. Here, the angle between the third type wafer slot 206 and point 208 is the second rotation angle. Specifically, in the measurement coordinate system, the center point of the third type wafer slot 206 is first determined, and then the center point of the third type wafer slot 206 and point 208 are respectively connected to the origin of the measurement coordinate system, that is, two line segments are obtained by connecting to the rotation center 203. The angle between these two line segments is the second rotation angle. At the same time, based on the positional relationship of the center point of the third type wafer slot 206 relative to point 208, the rotation direction is determined. Among them, the intersection of the diagonals of the square corresponding to the wafer slot can be used as the center point of the wafer slot.

[0055] Step S102 : determining the vertex positions of the four vertices and the angle information of the four sides of the square wafer to be aligned based on the target image.

[0056] In this step, the target image may refer to an image captured by a camera, and the target image is used to determine position information of the square wafer to be aligned.

[0057] In an embodiment of the present application, after obtaining the target image, the position information of the square wafer to be aligned in the image coordinate system can be determined according to the grayscale value of each pixel point in the target image, and the vertex positions of the four vertices of the square wafer to be aligned in the measurement coordinate system and the angle information of the four sides can be determined according to the position information of the square wafer to be aligned in the image coordinate system.

[0058] Here, two coordinate systems need to be established: a measurement coordinate system and an image coordinate system. The measurement coordinate system is a physical coordinate system with units of millimeters. The rotation center 203 can be used as the origin of the measurement coordinate system, and the horizontal direction of the mobile platform is used as the horizontal axis of the measurement coordinate system. The image coordinate system is a coordinate system determined based on the captured image and is used in units of pixels. The upper left corner of the camera's photosensitive unit can be used as the origin of the image coordinate system.

[0059] In an optional embodiment, executing step S102 includes: obtaining the grayscale value of each pixel in the target image; obtaining the grayscale value of each pixel in the target image; for each pixel, determining the difference between the grayscale value of multiple adjacent pixel points adjacent to the pixel point and the pixel point; determining the difference between two adjacent pixel points as the gradient of the two adjacent pixel points; determining the pixel points corresponding to multiple gradients greater than the gradient threshold as multiple edge pixel points of the square wafer to be aligned; based on the multiple edge pixel points of the square wafer to be aligned, determining the vertex positions of the four vertices of the square wafer to be aligned and the angle information of the four sides.

[0060] Here, after obtaining the grayscale value of each pixel, traverse each pixel, and determine the difference in grayscale value between the pixel and each adjacent pixel for each pixel. This difference is the grayscale value gradient, also called gradient. Compare the calculated gradient with the gradient threshold. If the gradient is greater than the gradient threshold, use the gradient as the target gradient, and use the pixel corresponding to the target gradient as the edge pixel of the square wafer to be aligned. Based on the edge pixel of the square wafer to be aligned, determine the vertex positions of the four vertices of the square wafer to be aligned and the angle information of the four sides.

[0061] In an optional embodiment, based on multiple edge pixel points of the square wafer to be aligned, the vertex positions of the four vertices of the square wafer to be aligned and the angle information of the four sides are determined, including: connecting the multiple edge pixel points through linear fitting to determine the position information of the square wafer to be aligned in the image coordinate system; based on the conversion relationship between the image coordinate system and the measurement coordinate system, the position information of the square wafer to be aligned in the image coordinate system is converted into the position information in the measurement coordinate system, the position information in the measurement coordinate system includes the vertex positions of the four vertices and the positions of the four sides; based on the positions of the four sides, the angle information of the four sides is determined.

[0062] Here, based on the conversion relationship between the image coordinate system and the measurement coordinate system, the vertex coordinates of the four vertices of the square wafer to be aligned in the image coordinate system are converted to vertex coordinates in the measurement coordinate system. The four vertices in the measurement coordinate system are sequentially connected to determine the positions of the four sides of the square wafer to be aligned in the measurement coordinate system. The conversion relationship between the image coordinate system and the measurement coordinate system is known from the prior art and will not be further described here.

[0063] Among them, the angle information of the four sides includes the first angle, the second angle, the third angle and the fourth angle. The first angle, the second angle, the third angle and the fourth angle are the angles between the first side, the second side, the third side and the fourth side of the square wafer to be aligned and the horizontal positive direction of the measurement coordinate system respectively. In the clockwise direction, the four sides of the square wafer to be aligned are the first side, the fourth side, the second side and the third side respectively.

[0064] Refer to the following Figure 3 Let's introduce the angle information of the four sides of the square wafer to be aligned.

[0065] Figure 3 A schematic diagram showing the angle information of the four sides of a square wafer to be aligned provided in an embodiment of the present application is shown.

[0066] like Figure 3 As shown, the four sides of the square wafer to be aligned are the first side 301, the second side 302, the third side 303 and the fourth side 304, the angle between the first side 301 and the horizontal positive direction is ɑ1, the angle between the second side 302 and the horizontal positive direction is ɑ2, the angle between the third side 303 and the horizontal positive direction is ɑ3, and the angle between the fourth side 304 and the horizontal positive direction is ɑ4.

[0067] Step S103: Determine a first rotation angle based on the angle information of the four sides.

[0068] In this step, the first rotation angle may refer to a rotation angle of the rotating platform, and the first rotation angle is used to place the square wafer to be aligned according to a target angle in the measurement coordinate system.

[0069] In an optional embodiment, executing step S103 includes: determining the average value of the first angle and the second angle as the horizontal angle; determining the average value of the third angle and the fourth angle as the vertical angle; determining the difference between the vertical angle and 90° as the rotated vertical angle; determining the average value of the horizontal angle and the rotated vertical angle as the reference angle; and determining the difference between the reference angle and the target angle as the first rotation angle.

[0070] Here, the horizontal angle is used to characterize the degree of parallelism between the two horizontal sides of the square wafer to be aligned and the horizontal direction of the measurement coordinate system, that is, Figure 3 The degree of parallelism between the first side 301 and the second side 302 and the horizontal direction. The smaller the horizontal angle, the more parallel the square wafer to be aligned is to the horizontal direction.

[0071] The vertical angle is used to characterize the degree of parallelism between the two vertical sides of the square wafer to be aligned and the vertical direction of the measurement coordinate system, that is, Figure 3The degree of parallelism between the third side 303 and the fourth side 304 and the vertical direction. The smaller the vertical angle, the more parallel the two vertical sides of the square wafer to be aligned are to the vertical direction.

[0072] The vertical rotation angle is used to convert the parallelism between the two vertical sides of the square wafer to be aligned and the vertical direction of the measurement coordinate system into the horizontal direction for characterization.

[0073] The reference angle is used to characterize the overall offset of the square wafer to be aligned in the horizontal direction.

[0074] by Figure 3 For example, the average horizontal angle is (ɑ1+ɑ2) / 2, and the average vertical angle is (ɑ3+ɑ4) / 2. Converting the average vertical angle to a horizontal angle is (ɑ3+ɑ4) / 2-90°, and the base angle is ((ɑ1+ɑ2) / 2+(ɑ3+ɑ4) / 2-90°) / 2=(ɑ1+ɑ2+ɑ3+ɑ4-180°) / 4.

[0075] If the target angle is 0°, the first rotation angle is (ɑ1+ɑ2+ɑ3+ɑ4-180°) / 4.

[0076] Step S104: controlling the rotating platform to rotate according to a first rotation angle.

[0077] In this step, after determining the first rotation angle, the control unit sends a control signal to the rotating platform, which drives the square wafer to be aligned to rotate so that the square wafer to be aligned is placed at a target angle with the horizontal axis in the measurement coordinate system.

[0078] Step S105 , determining the position of the rotated center point of the square wafer to be aligned and the offset distance between the rotated center point position and the target position based on the first rotation angle and the vertex positions of the four vertices.

[0079] In this step, the center point position may refer to the centroid position of the square wafer to be aligned, and the center point position is used to represent the position of the square wafer to be aligned in the measurement coordinate system.

[0080] The target position may refer to a desired position of the square wafer to be aligned after pre-alignment.

[0081] The offset distance includes a lateral offset distance and a longitudinal offset distance. The lateral offset distance may refer to a direction and distance of movement along a horizontal direction in a measurement coordinate system, and the longitudinal offset distance may refer to a direction and distance of movement along a vertical direction in a measurement coordinate system.

[0082] In an optional embodiment, executing step S105 includes: determining two diagonal lines of the square wafer to be aligned based on the vertex positions of the four vertices; determining the intersection position of the two diagonal lines as the center point position of the square wafer to be aligned before rotation; determining the center point position of the square wafer to be aligned after rotation based on the first rotation angle and the center point position before rotation; and determining the offset distance between the center point position after rotation and the target position.

[0083] Here, after determining the positions of the four vertices of the square wafer to be aligned before rotation, two spaced vertices are connected to obtain two diagonal lines. The intersection of these two diagonals is the center point position of the square wafer to be aligned before rotation, recorded as: (X1, Y1). Since the first rotation angle is known, the center point position of the square wafer to be aligned after rotation can be determined in the measurement coordinate system based on the center point position of the square wafer to be aligned before rotation, recorded as: (X2, Y2).

[0084] The target position is the set position, and its coordinates in the measurement coordinate system are (X0, Y0). The offset distance between the rotated center point and the target position is determined by determining the difference between the horizontal and vertical coordinates between the coordinates (X2, Y2) and (X0, Y0). When X2 - X0 > 0, the mobile platform is controlled to move in the negative horizontal direction, and the distance moved is the absolute value of the difference between the horizontal coordinates. When X2 - X0 < 0, the mobile platform is controlled to move in the positive horizontal direction, and the distance moved is the absolute value of the difference between the horizontal coordinates. When Y2 - Y0 > 0, the mobile platform is controlled to move in the negative vertical direction, and the distance moved is the absolute value of the difference between the vertical coordinates. When Y2 - Y0 < 0, the mobile platform is controlled to move in the positive vertical direction, and the distance moved is the absolute value of the difference between the vertical coordinates.

[0085] Step S106: Control the movement of the mobile platform based on the offset distance.

[0086] In this step, the mobile platform is controlled to move horizontally based on the lateral offset distance, and is controlled to move vertically based on the longitudinal offset distance, so that the square wafer to be aligned is moved to the target position in the measurement coordinate system to complete the position alignment.

[0087] It should be noted that when controlling the mobile platform to move in the horizontal direction or the vertical direction, it can first move in the horizontal direction and then move in the vertical direction; it can also first move in the vertical direction and then move in the horizontal direction. Technical personnel in this field can choose the specific order of movement directions according to actual conditions.

[0088] Compared with the square wafer pre-alignment method in the prior art, the present application can obtain the vertex positions of the four vertices of the square wafer and the angle information of the four sides through the target image of the square wafer, and determine the pre-alignment rotation angle and offset distance based on the vertex positions of the four vertices and the angle information of the four sides. By rotating first and then moving, the square wafer to be aligned is moved to the target position, solving the problem of being unable to pre-align the square wafer.

[0089] Based on the same inventive concept, an embodiment of the present application also provides a square wafer alignment system corresponding to the square wafer pre-alignment method. Since the principle of solving the problem by the system in the embodiment of the present application is similar to the above-mentioned square wafer pre-alignment method in the embodiment of the present application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be repeated.

[0090] See also Figure 4 , Figure 4 This is a schematic diagram of the structure of a square wafer pre-alignment system provided in an embodiment of the present application. Figure 4 As shown in FIG, the square wafer alignment system includes:

[0091] A control unit (not shown), a camera 401, and a mobile platform 402. The mobile platform 402 includes a rotating platform (not shown) on which a plurality of different types of silicon wafer slots are arranged.

[0092] The control unit executes the steps of the square wafer alignment method;

[0093] The control unit is connected to the camera 401 and the mobile platform 402 respectively to control the camera 401 and the mobile platform 402;

[0094] The camera 401 is located above the moving platform 402 to take pictures of the square wafer 403 to be aligned on the moving platform 402 .

[0095] The square wafer alignment system further includes a light source 404 , which is used to illuminate the square wafer to be aligned, so that the camera 401 can obtain a clear target image.

[0096] It should be noted that the control unit of the square wafer pre-alignment system includes a variety of software libraries.

[0097] Refer to the following Figure 5 To introduce the software architecture of the control unit.

[0098] Figure 5 A schematic diagram of the software architecture provided by an embodiment of the present application is shown.

[0099] like Figure 5As shown, the various software libraries include a camera control software library 501 , a database 502 , a light source control software library 503 , an image algorithm software library 504 , and a mobile platform control software library 505 .

[0100] The camera control software library 501 is connected to the camera to set camera parameters and control the camera to take pictures.

[0101] Database 502 is used to maintain various alignment information of the square wafer to be aligned, including at least the size, type, image coordinate system description, measurement coordinate system description, target position coordinates, target angle, process parameters for extracting the edge of the square wafer to be aligned, and coordinate description of the center point of the rotation axis of the mobile platform.

[0102] The light source control software library 503 communicates with the light source controller to set the brightness of the light source and control the switching of the light source.

[0103] The image algorithm software library 504 includes various image processing algorithms for the square wafer to be aligned, including at least camera image distortion correction, image coordinate system establishment, image coordinate system and mobile platform coordinate system conversion method, square piece edge extraction method, geometric center point correction method, reference angle calculation method, and mobile platform rotation and translation relationship calculation method.

[0104] The mobile platform control software library 505 includes horizontal movement control, vertical movement control, and rotation control of the mobile platform.

[0105] See also Figure 6 , Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 6 As shown in FIG, the electronic device 600 includes a processor 610 , a memory 620 and a bus 630 .

[0106] The memory 620 stores machine-readable instructions executable by the processor 610. When the electronic device 600 is running, the processor 610 communicates with the memory 620 via the bus 630. When the machine-readable instructions are executed by the processor 610, the above-mentioned Figure 1 The steps of the square wafer pre-alignment method in the method embodiment shown are specifically implemented in accordance with the method embodiment and will not be described in detail here.

[0107] The embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the computer program can execute the above-mentioned Figure 1 The steps of the square wafer pre-alignment method in the method embodiment shown are specifically implemented in accordance with the method embodiment and will not be described in detail here.

[0108] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0109] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. There may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed may be through some communication interface, indirect coupling or communication connection of devices or units, which may be electrical, mechanical or other forms.

[0110] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0111] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0112] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0113] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above-mentioned embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-mentioned embodiments within the technical scope disclosed in the present application, or perform equivalent replacements for some of the technical features thereof. These modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A square wafer pre-alignment method, characterized in that: The method comprises: receiving a feedback signal indicating that the square wafer to be aligned has been placed in the target wafer slot, and acquiring a target image corresponding to the square wafer to be aligned; Determining, based on the target image, vertex positions of four vertices of the square wafer to be aligned and angle information of four sides, and determining a first rotation angle based on the angle information of the four sides; Controlling the rotating platform to rotate according to the first rotation angle so that the square wafer to be aligned is placed at a target angle with respect to the abscissa axis in the measurement coordinate system; Determining a center point position of the square wafer to be aligned after rotation and an offset distance between the center point position after rotation and a target position based on the first rotation angle and the vertex positions of the four vertices; Controlling the movement of the mobile platform based on the offset distance so that the square wafer to be aligned moves to a target position in a measurement coordinate system to complete position alignment; Determining the vertex positions of the four vertices and the angle information of the four sides of the square wafer to be aligned based on the target image includes: Obtaining the grayscale value of each pixel in the target image, and for each pixel, determining the difference between the grayscale value of the pixel and that of multiple adjacent pixels; The difference between two adjacent pixels is determined as the gradient of the two adjacent pixels; Determine a plurality of corresponding pixel points whose values ​​are greater than a gradient threshold as a plurality of edge pixel points of the square wafer to be aligned; Determining position information of the square wafer to be aligned based on a plurality of edge pixel points of the square wafer to be aligned, the position information including vertex positions of four vertices and positions of four edges; Based on the positions of the four sides, angle information of the four sides is determined.

2. The method according to claim 1, characterized in that The determining the position information of the square wafer to be aligned based on a plurality of edge pixel points of the square wafer to be aligned includes: Connecting multiple edge pixel points by linear fitting to determine the position information of the square wafer to be aligned in the image coordinate system; Based on the conversion relationship between the image coordinate system and the measurement coordinate system, the position information of the square wafer to be aligned in the image coordinate system is converted into position information in the measurement coordinate system, where the position information in the measurement coordinate system includes the vertex positions of the four vertices and the positions of the four edges; The angle information of the four sides includes a first angle, a second angle, a third angle and a fourth angle. The first angle, the second angle, the third angle and the fourth angle are the angles between the first side, the second side, the third side and the fourth side of the square wafer to be aligned and the horizontal positive direction of the measurement coordinate system, respectively. In a clockwise direction, the four sides of the square wafer to be aligned are the first side, the fourth side, the second side and the third side, respectively.

3. The method according to claim 2, characterized in that The determining of the first rotation angle based on the angle information of the four sides includes: determining an average of the first angle and the second angle as a horizontal angle; determining an average of the third angle and the fourth angle as a vertical angle; The difference between the vertical angle and 90° is determined as the rotation vertical angle; Determine the average value of the horizontal angle and the rotation vertical angle as a reference angle; The difference between the reference angle and the target angle is determined as the first rotation angle.

4. The method according to claim 1, wherein The step of determining the position of the center point of the square wafer to be aligned after rotation and the offset distance between the center point position after rotation and the target position based on the first rotation angle and the vertex positions of the four vertices includes: determining two diagonal lines of the square wafer to be aligned based on the vertex positions of the four vertices; Determine the intersection of the two diagonal lines as the center point of the square wafer to be aligned before rotation; Determining the center point position of the square wafer to be aligned after rotation based on the first rotation angle and the center point position before rotation; Determine the offset distance between the rotated center point position and the target position.

5. The method according to claim 1, characterized in that Before receiving a feedback signal indicating that the square wafer to be aligned has been placed in the target wafer slot and obtaining a target image corresponding to the square wafer to be aligned, the method further includes: receiving external data, wherein the external data includes wafer information of a square wafer to be aligned; Based on the wafer information, a target wafer slot corresponding to the type of the square wafer to be aligned is determined.

6. The method according to claim 5, characterized in that After determining the target wafer slot corresponding to the type of the square wafer to be aligned based on the wafer information, the method further includes: Determining a second rotation angle based on the position of the target wafer slot on the rotating platform and the position where the wafer is placed by the external manipulator; The rotating platform is controlled to rotate according to the second rotation angle so that the position of the target wafer slot after rotation corresponds to the position where the external robot places the wafer.

7. A square wafer pre-alignment system, characterized in that: The system includes: a control unit, a camera, and a mobile platform, wherein the mobile platform includes a rotating platform, and a plurality of different types of wafer slots are arranged on the rotating platform; The control unit performs the steps of the square wafer pre-alignment method according to any one of claims 1 to 6; The control unit is connected to the camera and the mobile platform respectively to control the camera and the mobile platform; The camera is located above the moving platform to take pictures of the square wafer to be aligned on the moving platform.

8. An electronic device, characterized in that: include: A processor, a storage medium and a bus, wherein the storage medium stores machine-readable instructions executable by the processor. When the electronic device is running, the processor and the storage medium communicate through the bus, and the processor executes the machine-readable instructions to perform the steps of the square wafer pre-alignment method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the square wafer pre-alignment method according to any one of claims 1 to 6 are executed.

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