A method for determining the positioning accuracy of a wafer transmission system

Abstract

This application provides a method for determining the positioning accuracy of a wafer transfer system. The method includes: acquiring a first target image of a first mark on a target wafer and a second target image of a second mark on the target wafer; determining the current position of the first mark and the current position of the second mark based on the first and second target images; determining the current position of the center point of the target wafer and its placement angle based on the current positions of the first and second marks and the positional relationship between the reference positions of the first mark, the second mark, and the center point of the target wafer; and comparing the current position of the center point of the target wafer with the reference position of the center point and the placement angle with the reference angle to determine whether the positioning accuracy of the wafer transfer system meets the accuracy requirements. By employing the above method for determining the positioning accuracy of a wafer transfer system, the problem of being unable to accurately measure the repeatability positioning accuracy of the wafer transfer system is solved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically, to a method for determining the positioning accuracy of a wafer transport system. Background Technology

[0002] With the rapid development of semiconductor technology, the critical dimensions of wafer fabrication are gradually decreasing, while the complexity of wafer fabrication is constantly increasing, leading to increasingly stringent requirements for wafer processing. The level of wafer processing quality mainly depends on the precision of the processing and the precision of wafer transfer. The wafer transfer process is completed by the wafer transfer system. Therefore, in order to ensure the precision of wafer transfer, it is necessary to measure the repeatability and positioning accuracy of the wafer transfer system.

[0003] Currently, there is a lack of accurate measurement methods for the repeatability positioning accuracy of wafer transfer systems. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method for determining the positioning accuracy of a wafer transfer system, which solves the problem of being unable to accurately measure the repeatability positioning accuracy of the wafer transfer system.

[0005] In a first aspect, embodiments of this application provide a method for determining the positioning accuracy of a wafer transport system, applied to a wafer mounting repeatability inspection system. The wafer mounting repeatability inspection system includes a wafer carrier platform, and the method includes:

[0006] Receive the transfer completion signal sent by the wafer transport system indicating that the target wafer has been placed on the wafer carrier platform, and acquire the first target image of the first mark on the target wafer and the second target image of the second mark on the target wafer;

[0007] Based on the first target image and the second target image, determine the current position of the first marker and the current position of the second marker;

[0008] Based on the current positions of the first marker and the second marker, the current position and placement angle of the target wafer's center point are determined by utilizing the positional relationship between the reference positions of the first marker, the second marker, and the center point of the target wafer.

[0009] The current position of the target wafer's center point is compared with the center point reference position, and the placement angle is compared with the reference angle to determine whether the positioning accuracy of the wafer transport system meets the accuracy requirements.

[0010] Optionally, the wafer repeatability inspection system further includes a first camera and a second camera; acquiring a first target image of a first mark on the target wafer and a second target image of a second mark on the target wafer includes: controlling the first camera to take a picture of the first mark on the target wafer to acquire the first target image, and simultaneously controlling the second camera to take a picture of the second mark on the target wafer to acquire the second target image.

[0011] Optionally, determining the current position of the first marker and the current position of the second marker based on the first target image and the second target image includes: parsing the first target image and the second target image using an image matching algorithm to determine the position of the first marker and the position of the second marker in the image coordinate system; converting the position of the first marker in the image coordinate system to the position of the first marker in the measurement coordinate system based on the transformation relationship between the image coordinate system and the measurement coordinate system, and converting the position of the second marker in the image coordinate system to the position of the second marker in the measurement coordinate system; determining the position of the first marker in the measurement coordinate system as the current position of the first marker, and determining the position of the second marker in the measurement coordinate system as the current position of the second marker.

[0012] Optionally, based on the current positions of the first and second marks, and utilizing the positional relationship between the reference positions of the first mark, the second mark, and the center point of the target wafer, the current position and placement angle of the target wafer are determined, including: based on the current positions of the first and second marks, and utilizing the positional relationship between the reference positions of the first and second marks and the reference position of the center point of the target wafer, the current position of the target wafer is determined; the center points of the first and second marks are determined; the center points of the first and second marks are connected to obtain a line connecting the center points of the marks; and the angle between the extension of the line connecting the center points of the marks and the horizontal direction of the measurement coordinate system is determined as the placement angle of the target wafer.

[0013] Optionally, the target wafers include multiple wafers, and the method further includes: sequentially placing the multiple target wafers into the wafer carrier platform of the wafer mounting repeatability inspection system; for each target wafer placed in the wafer carrier platform, determining the current position of the center point and the placement angle of the target wafer; and determining whether the positioning accuracy of the wafer transport system meets the accuracy requirements based on the current position of the center point and the placement angle of each of the multiple target wafers.

[0014] Optionally, based on the current position and placement angle of the center points of multiple target wafers, determine whether the positioning accuracy of the wafer transfer system meets the accuracy requirements, including: determining the comprehensive position deviation value and comprehensive angle deviation value of the multiple target wafers based on the current position and placement angle of their respective center points; determining whether the comprehensive position deviation value is less than a position deviation threshold; determining whether the comprehensive angle deviation value is less than an angle deviation threshold; if the comprehensive position deviation value is less than the position deviation threshold and the comprehensive angle deviation value is less than the angle deviation threshold, then the positioning accuracy of the wafer transfer system meets the requirements; if the comprehensive position deviation value is not less than the position deviation threshold, and / or the comprehensive angle deviation value is not less than the angle deviation threshold, then the positioning accuracy of the wafer transfer system does not meet the requirements.

[0015] Optionally, based on the current position of the center point and the placement angle of each of the multiple target wafers, the comprehensive position deviation value and comprehensive angle deviation value of the multiple target wafers are determined, including: calculating the difference between the current position of the center point of each of the multiple target wafers and the reference position of the center point, to obtain multiple position differences; determining the average of the multiple position differences as the comprehensive position deviation value; calculating the difference between the placement angle of each of the multiple target wafers and the reference angle, to obtain multiple angle differences; and determining the average of the multiple angle differences as the comprehensive angle deviation value.

[0016] Secondly, embodiments of this application also provide a wafer mounting repeatability inspection system, the system comprising:

[0017] Control unit, first camera, second camera, and wafer carrier platform;

[0018] The control unit executes the steps of the positioning accuracy determination method for the wafer transfer system described above.

[0019] The control unit is connected to the first camera and the second camera respectively to control the first camera and the second camera;

[0020] The first and second cameras are positioned above the wafer carrier platform to photograph the target wafer on the platform.

[0021] Thirdly, embodiments of this application also provide an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the positioning accuracy determination method for the wafer transfer system described above are performed.

[0022] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the positioning accuracy determination method for a wafer transfer system as described above.

[0023] The embodiments of this application bring the following beneficial effects:

[0024] This application provides a method for determining the positioning accuracy of a wafer transfer system. It can acquire a first target image corresponding to a first marker and a second target image corresponding to a second marker using a first camera and a second camera respectively. Based on the first and second target images, it determines the current position and placement angle of the center point of the target wafer. Then, based on the current position and placement angle of the center point of the target wafer, it determines whether the positioning accuracy of the wafer transfer system meets the accuracy requirements. Compared with existing methods for determining the positioning accuracy of wafer transfer systems, this method solves the problem of not being able to accurately measure the repeatability positioning accuracy of the wafer transfer system.

[0025] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A flowchart is shown below illustrating the method for determining the positioning accuracy of a wafer transport system provided in an embodiment of this application.

[0028] Figure 2 This diagram illustrates the device location of the wafer mounting repeatability testing system provided in an embodiment of this application.

[0029] Figure 3 This paper shows a schematic diagram of the wafer repeatability testing system provided in an embodiment of this application.

[0030] Figure 4 A schematic diagram of the control unit provided in an embodiment of this application is shown;

[0031] Figure 5 A schematic diagram of the structure of the electronic device provided in the embodiments of this application is shown. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0033] It is worth noting that prior to this application, with the rapid development of semiconductor technology, the critical dimensions of wafer fabrication have gradually decreased, while the complexity of wafer fabrication has continuously increased, leading to increasingly stringent requirements for wafer processing. The level of wafer processing capability primarily depends on the precision of the processing and the precision of wafer transfer. Since the wafer transfer process is completed by the wafer transfer system, it is necessary to measure the repeatability positioning accuracy of the wafer transfer system to ensure wafer transfer precision. Currently, there is a lack of accurate measurement methods for the repeatability positioning accuracy of the wafer transfer system.

[0034] Based on this, embodiments of this application provide a method for determining the positioning accuracy of a wafer transfer system, so as to improve the accuracy when measuring the repeatability positioning accuracy of the wafer transfer system.

[0035] Please see Figure 1 , Figure 1 This is a flowchart illustrating a method for determining the positioning accuracy of a wafer transport system provided in an embodiment of this application. Figure 1 As shown in the embodiments of this application, the method for determining the positioning accuracy of a wafer transport system is applied to a wafer mounting repeatability inspection system. The wafer mounting repeatability inspection system includes a wafer carrier platform, and the method includes:

[0036] Step S101: Receive the transfer completion signal sent by the wafer transfer system indicating that the target wafer has been placed on the wafer carrier platform, and acquire the first target image of the first mark on the target wafer and the second target image of the second mark on the target wafer.

[0037] In this step, the wafer transport system can refer to the system that transports wafers, and the wafer transport system is connected to the wafer loading repeatability detection system.

[0038] The target wafer may refer to the wafer being transferred, and the target wafer has a first mark and a second mark.

[0039] The first mark may refer to a graphic mark, which is used to determine the center point position and placement angle of the target wafer.

[0040] The second mark may refer to a graphic mark with the same shape as the first mark. The second mark is used together with the first mark to locate the center point and placement angle of the target wafer.

[0041] For example, the shapes of the first mark and the second mark can be crosses, squares, or right-angled broken line segments.

[0042] In this embodiment, the wafer transfer system places the target wafer bearing the first and second marks onto the wafer carrier platform of the wafer loading repeatability inspection system at a predetermined loading angle, such as 0°. Then, it sends a loading completion signal to the wafer loading repeatability inspection system via a network interface. After receiving the loading completion signal from the wafer transfer system, the wafer loading repeatability inspection system turns on its light source and adjusts the brightness to the optimal value so that the first and second marks present the best contrast in the camera's field of view, i.e., the first and second marks can be clearly seen. Then, the camera takes pictures to obtain the first target image corresponding to the first mark on the target wafer and the second target image corresponding to the second mark on the target wafer.

[0043] In an optional embodiment, the wafer repeatability inspection system further includes a first camera and a second camera; the execution step S101 includes: controlling the first camera to take a picture of the first mark on the target wafer to obtain a first target image, and simultaneously controlling the second camera to take a picture of the second mark on the target wafer to obtain a second target image.

[0044] Here, the wafer repeatability inspection system uses two cameras: a first camera and a second camera. The first camera is controlled to take a picture of a first mark, and the second camera is controlled to take a picture of a second mark, thereby obtaining a first target image corresponding to the first mark and a second target image corresponding to the second mark, respectively. It should be noted that when the first and second cameras are taking pictures, they simultaneously capture images of the first and second marks.

[0045] The following reference Figure 2 This section introduces the equipment installation location of the wafer repeatability testing system.

[0046] Figure 2 A schematic diagram of the device location of the wafer repeatability testing system provided in an embodiment of this application is shown.

[0047] like Figure 2As shown, a first camera 201 and a second camera 202 are mounted above a wafer carrier platform 206. A target wafer 205 is placed on the wafer carrier platform 206. A first adjustment platform 203 is connected to the first camera 201 and is used to adjust the position of the first camera 201 so that a first mark on the target wafer 205 is within the field of view of the first camera 201. A second adjustment platform 204 is connected to the second camera 202 and is used to adjust the position of the second camera 202 so that a second mark on the target wafer 205 is within the field of view of the second camera 202. The first adjustment platform 203 and the second adjustment platform 204 are fixed on a bracket 207.

[0048] Specifically, when starting to measure the positioning accuracy of the wafer transfer system, the positions of the first adjustment platform 203 and the second adjustment platform 204 must first be calibrated so that the first camera 201 can clearly capture the first target image of the first mark and the second target image of the second mark.

[0049] Step S102: Based on the first target image and the second target image, determine the current position of the first marker and the current position of the second marker.

[0050] In this step, the first target image can refer to the image taken relative to the first mark on the target wafer, and the first target image is used to determine the current position of the first mark.

[0051] The second target image can refer to an image taken of a second mark on a target wafer, and the second target image is used to determine the current position of the second mark.

[0052] In this embodiment of the application, after the camera takes pictures of the first mark and the second mark, a first target image corresponding to the first mark and a second target image corresponding to the second mark can be obtained. The position of the first mark can be determined by the first target image, and the position of the second mark can be determined by the second target image.

[0053] In an optional embodiment, step S102 includes: parsing the first target image and the second target image using an image matching algorithm to determine the position of the first marker and the position of the second marker in the image coordinate system; based on the transformation relationship between the image coordinate system and the measurement coordinate system, converting the position of the first marker in the image coordinate system to the position of the first marker in the measurement coordinate system, and converting the position of the second marker in the image coordinate system to the position of the second marker in the measurement coordinate system; determining the position of the first marker in the measurement coordinate system as the current position of the first marker, and determining the position of the second marker in the measurement coordinate system as the current position of the second marker.

[0054] Here, the image matching algorithm can refer to the recognition algorithm for the first marker and the second marker. The image matching algorithm is used to determine the first marker from the first target image and to identify the second marker from the second target image.

[0055] The image coordinate system can refer to the coordinate system established relative to the first camera and the second camera. The unit of the image coordinate system is pixels, and the image coordinate system includes the first image coordinate system and the second image coordinate system.

[0056] The first image coordinate system is used to determine the position of the first mark in the image coordinate system, and the origin of the first image coordinate system is the upper left corner of the first camera photosensitive unit.

[0057] The second image coordinate system is used to determine the position of the second mark in the image coordinate system. The origin of the second image coordinate system is the upper left corner of the second camera's photosensitive unit.

[0058] The measurement coordinate system can refer to a plane rectangular coordinate system. The unit of the measurement coordinate system is millimeters. The origin of the measurement coordinate system can be any position on the plane where the upper surface of the support is located. For example, it can be the midpoint between the first adjustment platform and the second adjustment platform on the plane where the upper surface of the support is located. The horizontal axis of the measurement coordinate system is parallel to the horizontal side of the upper surface of the support, and the vertical axis of the measurement coordinate system is parallel to the vertical side of the upper surface of the support. The upper surface of the support is rectangular. The horizontal side of the upper surface of the support refers to the two longer sides of the support, and the vertical side of the upper surface of the support refers to the two shorter sides of the support.

[0059] Specifically, after establishing the image coordinate system, the transformation relationship between the image coordinate system and the measurement coordinate system can be determined based on the position of the origin of the image coordinate system in the measurement coordinate system and the dimensional transformation relationship between the image coordinate system and the measurement coordinate system. That is, the position coordinates of each point in the image coordinate system in the measurement coordinate system can be determined. The dimensional transformation relationship between the image coordinate system and the measurement coordinate system can specify how many millimeters one pixel equals.

[0060] In this way, after acquiring the first target image and the second target image, the position coordinates of the first mark and the second mark in the image coordinate system can be determined. Then, based on the transformation relationship between the image coordinate system and the measurement coordinate system, the position coordinates of the first mark and the second mark in the measurement coordinate system can be determined.

[0061] Step S103: Based on the current position of the first marker and the current position of the second marker, the current position of the center point of the target wafer and the placement angle are determined by utilizing the positional relationship between the reference positions of the first marker, the second marker and the center point of the target wafer.

[0062] In this step, the reference position can refer to the position where there is no positional deviation after the wafer transfer system transfers the target wafer. The reference position is used to determine the current position of the center point of the target wafer and the placement angle. The reference position is the coordinate position in the measurement coordinate system.

[0063] In this embodiment of the application, after determining the current position of the first mark and the current position of the second mark, the current position of the center point of the target wafer and the placement angle can be calculated based on the positional relationship between the reference positions of the first mark, the second mark and the center point of the target wafer.

[0064] In an optional embodiment, step S103 is performed as follows: Based on the current position of the first mark and the current position of the second mark, the current position of the center point of the target wafer is determined by utilizing the positional relationship between the reference position of the first mark, the reference position of the second mark, and the reference position of the center point of the target wafer; the center point of the first mark and the center point of the second mark are determined; the center point of the first mark and the center point of the second mark are connected to obtain the line connecting the center points of the marks; the angle between the extension of the line connecting the center points of the marks and the horizontal direction of the measurement coordinate system is determined as the placement angle of the target wafer.

[0065] Here, the current position of the target wafer's center point can be determined first based on the positions of the first and second markers, and then the placement angle of the target wafer can be determined. Alternatively, the placement angle of the target wafer can be determined first, and then the current position of the target wafer's center point can be determined. The positional relationship between the first marker, the second marker, and the reference position of the target wafer's center point can be determined as follows: First, give the reference coordinates of the three points. For example, if the reference position of the first marker is [10, 10], the reference position of the second marker is [-10, 10], and the reference position of the target wafer's center point is [0, 1], then the positional relationship can be determined using the following two formulas: X1-X0+X2-X0=0, Y1-Y0+Y2-Y0=18, where X1 represents the x-coordinate of the first marker's reference position, Y1 represents the y-coordinate of the first marker's reference position, X2 represents the x-coordinate of the second marker's reference position, Y2 represents the y-coordinate of the second marker's reference position, X0 represents the x-coordinate of the target wafer's center point's reference position, and Y0 represents the y-coordinate of the target wafer's center point's reference position. Thus, when the current position of the first marker is [9, 10] and the current position of the second marker is [-11, 10], the current position of the center point of the target wafer can be calculated as [-1, 1] using the two calculation formulas mentioned above.

[0066] The placement angle of the target wafer can also be determined based on the positions of the first and second marks. Specifically, first, the center points of the first and second marks are determined according to their shapes. Taking a cross shape as an example, the center points of the first and second marks are at the intersection of the cross. Then, the center points of the first and second marks are connected, and the angle between the extension of this line and the horizontal direction of the measurement coordinate system is determined as the placement angle of the target wafer. This angle is actually the angle between the extension of the line and the horizontal line that passes through the first mark and is parallel to the horizontal axis. The center point of the first mark is taken as the vertex of the angle. In this way, the direction of rotation can be determined by the sign of the angle.

[0067] Step S104: Compare the current position of the center point of the target wafer with the reference position of the center point and the placement angle with the reference angle to determine whether the positioning accuracy of the wafer transfer system meets the accuracy requirements.

[0068] In this step, the accuracy requirement refers to the requirements for the current position of the center point of the target wafer and the placement angle. The accuracy requirement is used to evaluate the positioning accuracy of the wafer transport system.

[0069] In this embodiment, the current position of the center point of the target wafer is compared with the reference position of the center point, and the placement angle is also compared with the reference angle. Based on the comparison results, it can be determined whether the positioning accuracy of the wafer transfer system meets the accuracy requirements. For example, if the difference between the current position of the center point of the target wafer and the reference position of the center point is less than a set threshold, and the difference between the placement angle and the reference angle is less than a set threshold, then it is determined that the positioning accuracy of the wafer transfer system meets the accuracy requirements.

[0070] In an optional embodiment, the target wafers include multiple wafers, and the method further includes: sequentially placing the multiple target wafers into the wafer carrier platform of the wafer mounting repeatability inspection system; determining the current position of the center point and the placement angle of each target wafer placed in the wafer carrier platform; and determining whether the positioning accuracy of the wafer transport system meets the accuracy requirements based on the current position of the center point and the placement angle of each of the multiple target wafers.

[0071] Here, the positioning accuracy of the wafer transport system can be determined by the current position and placement angle of the center point of each of the multiple target wafers. Specifically, the wafer transport system places individual target wafers from the multiple target wafers onto the wafer carrier platform of the wafer mounting repeatability inspection system in sequence. The wafer mounting repeatability inspection system determines the current position and placement angle of the center point of each target wafer in sequence, and determines whether the positioning accuracy of the wafer transport system meets the accuracy requirements based on the current position and placement angle of the center point of each target wafer.

[0072] In one optional embodiment, determining whether the positioning accuracy of the wafer transfer system meets the accuracy requirements based on the current position of the center point of multiple target wafers and their placement angle includes: determining the comprehensive position deviation value and comprehensive angle deviation value of the multiple target wafers based on the current position of their respective center points and their placement angle; determining whether the comprehensive position deviation value is less than a position deviation threshold; determining whether the comprehensive angle deviation value is less than an angle deviation threshold; if the comprehensive position deviation value is less than the position deviation threshold and the comprehensive angle deviation value is less than the angle deviation threshold, then the positioning accuracy of the wafer transfer system meets the requirements; if the comprehensive position deviation value is not less than the position deviation threshold, and / or the comprehensive angle deviation value is not less than the angle deviation threshold, then the positioning accuracy of the wafer transfer system does not meet the requirements.

[0073] Here, the comprehensive position deviation value can refer to the target position value of multiple position deviation values. The comprehensive position deviation value is used to determine the overall deviation of multiple position deviation values. For example, the target position value includes, but is not limited to, any one of the following: the mean, maximum, and minimum of multiple position deviation values.

[0074] The comprehensive angle deviation value can refer to the target angle value of multiple angle deviation values. The comprehensive angle deviation value is used to determine the overall deviation of multiple angle deviation values. For example, the target angle value includes, but is not limited to, any one of the following: the mean, maximum, and minimum of multiple angle deviation values.

[0075] The position deviation threshold refers to the maximum position deviation that meets the position accuracy requirements. The position deviation threshold is used to determine whether the overall position deviation value does not meet the position accuracy requirements.

[0076] The angle deviation threshold refers to the maximum angle deviation that meets the angle accuracy requirements. The angle deviation threshold is used to determine whether the overall angle deviation value does not meet the angle accuracy requirements.

[0077] Specifically, it is determined whether the overall position deviation value is less than a position deviation threshold and whether the overall angle deviation value is less than an angle deviation threshold. If both the overall position deviation value and the overall angle deviation value are less than the position deviation threshold, the positioning accuracy of the wafer transfer system is deemed to meet the requirements. If either the overall position deviation value or the overall angle deviation value is not less than the corresponding deviation threshold, the positioning accuracy of the wafer transfer system is deemed not to meet the requirements. The position deviation threshold and angle deviation threshold are determined based on experience or process requirements.

[0078] In one optional embodiment, based on the current position of the center point and the placement angle of each of the multiple target wafers, the comprehensive position deviation value and comprehensive angle deviation value corresponding to the multiple target wafers are determined, including: calculating the difference between the current position of the center point of each of the multiple target wafers and the reference position of the center point, to obtain multiple position differences; determining the average of the multiple position differences as the comprehensive position deviation value; calculating the difference between the placement angle of each of the multiple target wafers and the reference angle, to obtain multiple angle differences; and determining the average of the multiple angle differences as the comprehensive angle deviation value.

[0079] Here, we first calculate the difference between the current position of the center point of each target wafer and the reference position. Then, we use the average of multiple position differences to characterize the deviation between the center positions of multiple target wafers and the reference positions. A larger average position difference indicates a larger position deviation and lower accuracy, while a smaller average position difference indicates a smaller position deviation and higher accuracy. Next, we calculate the difference between the placement angle of each target wafer and the reference angle. Then, we use the average of multiple angle differences to characterize the deviation between the placement angle of multiple target wafers and the reference angle. A larger average angle difference indicates a larger angle deviation and lower accuracy, while a smaller average angle difference indicates a smaller angle deviation and higher accuracy.

[0080] Compared with existing methods for determining the positioning accuracy of wafer transfer systems, this application can acquire a first target image corresponding to a first marker and a second target image corresponding to a second marker using a first camera and a second camera respectively. Based on the first and second target images, the current position and placement angle of the center point of the target wafer are determined. Based on the current position and placement angle of the center point of the target wafer, it can determine whether the positioning accuracy of the wafer transfer system meets the accuracy requirements. At the same time, by determining the comprehensive position deviation value and comprehensive angle deviation value of multiple target wafers, the positioning accuracy of the wafer transfer system can be repeatedly measured, which can more accurately determine the positioning accuracy of the wafer transfer system and solve the problem of not being able to accurately measure the repeatability positioning accuracy of the wafer transfer system.

[0081] Based on the same inventive concept, this application also provides a wafer loading repeatability detection system corresponding to the wafer transfer system positioning accuracy determination method. Since the system in this application solves the problem in a similar way to the wafer transfer system positioning accuracy determination method described above in this application, the implementation of the system can refer to the implementation of the method, and the repeated parts will not be described again.

[0082] Please see Figure 3 , Figure 3 This is a schematic diagram of a wafer mounting repeatability testing system provided in an embodiment of this application. Figure 3 As shown, the wafer-on-wafer repeatability inspection system 300 includes:

[0083] Control unit 310, first camera 320, second camera 330, and wafer carrier platform (not shown in the figure);

[0084] The control unit executes steps such as those used in determining the positioning accuracy of a wafer transfer system.

[0085] The control unit 310 is connected to the first camera 320 and the second camera 330 respectively to control the first camera 301 and the second camera 302;

[0086] The first camera 320 and the second camera 330 are located above the wafer carrier platform to take pictures of the target wafer on the wafer carrier platform.

[0087] The wafer carrier platform is used to carry the target wafer.

[0088] The wafer repeatability inspection system 300 also includes a light source (not shown in the figure), and a control unit 310 is connected to the light source to adjust the brightness of the light source so that the markings on the target wafer achieve the best contrast in the camera's field of view.

[0089] The wafer repeatability inspection system 300 further includes a first adjustment platform and a second adjustment platform (not shown in the figure). The first adjustment platform is used to adjust the position of the first camera 320, and the second adjustment platform is used to adjust the position of the second camera 330, so that the first mark on the target wafer is in the field of view of the first camera 320, and the second mark is in the field of view of the second camera 330.

[0090] The control unit 310 is described below.

[0091] Figure 4 A schematic diagram of the control unit provided in an embodiment of this application is shown.

[0092] like Figure 4 As shown, the control unit 310 includes a camera control subunit 311, a database subunit 312, a light source control subunit 313, an image algorithm subunit 314, a transmission system communication subunit 315, and a data recording subunit 316.

[0093] The camera control subunit 311 may refer to a camera control software library, which is used to set camera parameters, control the camera to take pictures and transmit images. Setting camera parameters includes setting the camera's exposure time and camera gain.

[0094] Database subunit 312 is used to maintain various information for wafer repeatability testing, including: the relative positional relationship between the first mark and the second mark on the target wafer, the positional relationship between the first mark, the second mark and the center point of the target wafer, the transformation relationship between the image coordinate system and the measurement coordinate system, and the extraction of image parameters of the first mark and the second mark on the target wafer. The positional relationship between the three includes the distance and angle between the center point of the target wafer and the first mark, and the distance and angle between the center point of the target wafer and the second mark.

[0095] The light source control subunit 313 may refer to a light source control software library, which is used to control optical switches and set the brightness of the light source.

[0096] Image algorithm subunit 314 may refer to an image algorithm software library, used to locate the positions of the first and second marks on the target wafer using image processing algorithms, and calculate the current position of the target wafer's center point based on the positional relationship between the first and second marks and the center point of the target wafer. Through repeatable measurements, the difference between the current position of the center point of each target wafer and the reference position of the center point, as well as the difference between the placement angle of each target wafer and the reference angle, are obtained, thereby calculating the comprehensive positional deviation value and comprehensive angle deviation value of multiple target wafers.

[0097] The transmission system communication subunit 315 may refer to a software library that communicates with the wafer transmission system. The transmission system communication subunit 315 communicates with the wafer transmission system through a network interface to obtain the wafer loading completion signal.

[0098] The data recording subunit 316 may refer to a data recording software library, which is used to record the data obtained in each calculation. The data includes at least the position coordinates of the center point of the target wafer and the placement angle of the target wafer.

[0099] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 5 As shown, the electronic device 400 includes a processor 410, a memory 420, and a bus 430.

[0100] The memory 420 stores machine-readable instructions executable by the processor 410. When the electronic device 400 is running, the processor 410 communicates with the memory 420 via the bus 430. When the machine-readable instructions are executed by the processor 410, they can perform the operations described above. Figure 1 The steps of the method for determining the positioning accuracy of the wafer transfer system in the illustrated method embodiment can be found in the method embodiment for specific implementation methods, which will not be repeated here.

[0101] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 The steps of the method for determining the positioning accuracy of the wafer transfer system in the illustrated method embodiment can be found in the method embodiment for specific implementation methods, which will not be repeated here.

[0102] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0104] The units described as separate components may or may not be physically separate. 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 the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0105] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0106] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0107] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining the positioning accuracy of a wafer transmission system, characterized in that, An application in a wafer mounting repeatability inspection system, the wafer mounting repeatability inspection system including a wafer carrier platform, the method comprising: The system receives a signal from the wafer transport system indicating that the target wafer has been placed on the wafer carrier platform. It then acquires a first target image of a first mark on the target wafer and a second target image of a second mark on the target wafer. The target wafer has a first mark and a second mark with the same shape, and both the first mark and the second mark are graphic marks. Based on the first target image and the second target image, determine the current position of the first marker and the current position of the second marker; Based on the current positions of the first marker and the second marker, the current position and placement angle of the target wafer's center point are determined by utilizing the positional relationship between the reference positions of the first marker, the second marker, and the center point of the target wafer. The current position of the center point of the target wafer is compared with the reference position of the center point and the placement angle is compared with the reference angle to determine whether the positioning accuracy of the wafer transfer system meets the accuracy requirements. Based on the current positions of the first and second markers, and utilizing the positional relationship between the reference positions of the first marker, the second marker, and the center point of the target wafer, the current position and placement angle of the target wafer's center point are determined, including: Based on the current position of the first marker and the current position of the second marker, the current position of the center point of the target wafer is determined by utilizing the positional relationship between the reference position of the first marker, the reference position of the second marker, and the reference position of the center point of the target wafer. Determine the center point of the first mark and the center point of the second mark; Connect the center point of the first mark and the center point of the second mark to obtain a line connecting the center points of the marks; The angle between the extension of the line connecting the center points of the marks and the horizontal direction of the measurement coordinate system is determined as the placement angle of the target wafer. The target wafers include multiple wafers, and the method further includes: Based on the current position and placement angle of the center point of each of the multiple target wafers, determine whether the positioning accuracy of the wafer transport system meets the accuracy requirements. The following methods can be used to determine whether the positioning accuracy of the wafer transfer system meets the accuracy requirements: Based on the current position and placement angle of the center point of each of the multiple target wafers, determine the comprehensive positional deviation value and comprehensive angle deviation value of the multiple target wafers; Determine whether the overall position deviation value is less than the position deviation threshold, and whether the overall angle deviation value is less than the angle deviation threshold; If the overall position deviation value is less than the position deviation threshold and the overall angle deviation value is less than the angle deviation threshold, then the positioning accuracy of the wafer transfer system is determined to meet the requirements.

2. The method according to claim 1, characterized in that, The wafer loading repeatability inspection system also includes a first camera and a second camera; The acquisition of a first target image of a first mark on a target wafer and a second target image of a second mark on a target wafer includes: The system controls a first camera to take a picture of a first mark on a target wafer to obtain a first target image, and simultaneously controls a second camera to take a picture of a second mark on a target wafer to obtain a second target image.

3. The method according to claim 1, characterized in that, Determining the current position of the first marker and the current position of the second marker based on the first target image and the second target image includes: The first target image and the second target image are analyzed using an image matching algorithm to determine the positions of the first marker and the second marker in the image coordinate system; Based on the transformation relationship between the image coordinate system and the measurement coordinate system, the position of the first mark in the image coordinate system is converted to the position of the first mark in the measurement coordinate system, and the position of the second mark in the image coordinate system is converted to the position of the second mark in the measurement coordinate system. The position of the first mark in the measurement coordinate system is determined as the current position of the first mark, and the position of the second mark in the measurement coordinate system is determined as the current position of the second mark.

4. The method according to claim 1, characterized in that, The method further includes: Multiple target wafers are sequentially placed into the wafer carrier platform of the wafer mounting repeatability inspection system. For each target wafer placed in the wafer carrier platform, determine the current position of the center point and the placement angle of the target wafer.

5. The method according to claim 1, characterized in that, The method further includes: If the overall position deviation value is not less than the position deviation threshold, and / or the overall angle deviation value is not less than the angle deviation threshold, then the positioning accuracy of the wafer transfer system is determined to be unsatisfactory.

6. The method according to claim 1, characterized in that, The determination of the comprehensive positional deviation value and comprehensive angular deviation value corresponding to the multiple target wafers based on the current position of their respective center points and placement angles includes: Calculate the difference between the current position of the center point of each of the multiple target wafers and the reference position of the center point to obtain multiple position differences; The average of multiple position differences is determined as the comprehensive position deviation value; Calculate the difference between the placement angle of each of the multiple target wafers and the reference angle to obtain multiple angle differences; The average of the differences between multiple angles is determined as the comprehensive angle deviation value.

7. A wafer mounting repeatability inspection system, characterized in that, The system includes: a control unit, a first camera, a second camera, and a wafer carrier platform; The control unit performs the steps of the wafer transfer system positioning accuracy determination method as described in any one of claims 1 to 6; The control unit is connected to the first camera and the second camera respectively to control the first camera and the second camera; The first and second cameras are positioned above the wafer carrier platform to take pictures of the target wafer on the wafer carrier platform.

8. An electronic device, characterized in that, include: The device includes a processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is in operation, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the positioning accuracy determination method for a wafer transfer system 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, which, when executed by a processor, performs the steps of the method for determining the positioning accuracy of a wafer transport system as described in any one of claims 1 to 6.

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