CN114628301A - Positioning precision determination method of wafer transmission system - Google Patents
Positioning precision determination method of wafer transmission system Download PDFInfo
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- CN114628301A CN114628301A CN202210285555.XA CN202210285555A CN114628301A CN 114628301 A CN114628301 A CN 114628301A CN 202210285555 A CN202210285555 A CN 202210285555A CN 114628301 A CN114628301 A CN 114628301A
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- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/68—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for positioning, orientation or alignment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/677—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations
Abstract
The application provides a method for determining the positioning accuracy of a wafer transmission system, which comprises the following steps: 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 marker and the current position of the second marker based on the first target image and the second target image; determining the current position and the placing angle of the central point of the target wafer by utilizing the position relation among the reference positions of the first mark, the second mark and the central point of the target wafer based on the current position of the first mark and the current position of the second mark; and respectively comparing the current position of the central point of the target wafer with the reference position of the central point and the placing angle with the reference angle, and determining whether the positioning precision of the wafer transmission system meets the precision requirement. By adopting the method for determining the positioning precision of the wafer transmission system, the problem that the loading repeatability positioning precision of the wafer transmission system cannot be accurately measured is solved.
Description
Technical Field
The application relates to the technical field of semiconductors, in particular to a method for determining positioning accuracy of a wafer transmission system.
Background
With the rapid development of semiconductor technology, the critical dimension of wafer processing is gradually reduced, the complexity of wafer processing is continuously increased, and the process requirement for wafers is higher and higher. The process level of the wafer mainly depends on the process machining precision and the wafer transmission precision, and the wafer transmission process is completed by the wafer transmission system, so the wafer loading repeatability positioning precision of the wafer transmission system needs to be measured in order to ensure the wafer transmission precision.
At present, a relatively accurate measuring method is lacked for the upper piece repeatability positioning precision of a wafer transmission system.
Disclosure of Invention
In view of this, an object of the present application is to provide a method for determining a positioning accuracy of a wafer transfer system, which solves the problem that the loading repeatability positioning accuracy of the wafer transfer system cannot be accurately measured.
In a first aspect, an embodiment of the present application provides a method for determining a positioning accuracy of a wafer transmission system, which is applied to a wafer loading repeatability detection system, where the wafer loading repeatability detection system includes a wafer bearing platform, and the method includes:
receiving a transfer completion signal sent by a wafer transmission system and indicating that a target wafer is placed in a wafer bearing platform, and 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;
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;
determining the current position and the placing angle of the central point of the target wafer by utilizing the position relation among the reference positions of the first mark, the second mark and the central point of the target wafer based on the current position of the first mark and the current position of the second mark;
and respectively comparing the current position of the central point of the target wafer with the reference position of the central point and the placing angle with the reference angle, and determining whether the positioning precision of the wafer transmission system meets the precision requirement.
Optionally, the wafer-loading repeatability detection system further includes a first camera and a second camera; 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, comprising: and controlling the first camera to photograph the first mark on the target wafer to obtain a first target image, and simultaneously controlling the second camera to photograph the second mark on the target wafer to obtain a second target image.
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 comprises: analyzing the first target image and the second target image by using an image matching algorithm, and determining the position of a first mark and the position of a second mark in an image coordinate system; based on the conversion relation between the image coordinate system and the measurement coordinate system, converting the position of the first mark under the image coordinate system into the position of the first mark under the measurement coordinate system, and converting the position of the second mark under the image coordinate system into the position of the second mark under the measurement coordinate system; and determining the position of the first mark in the measurement coordinate system as the current position of the first mark, and determining the position of the second mark in the measurement coordinate system as the current position of the second mark.
Optionally, determining the current position and the placing angle of the center point of the target wafer by using the position relationship among the reference positions of the first mark, the second mark and the center point of the target wafer based on the current position of the first mark and the current position of the second mark, includes: determining the current position of the central point of the target wafer by utilizing the position relationship among the reference position of the first mark, the reference position of the second mark and the reference position of the central point of the target wafer based on the current position of the first mark and the current position of the second mark; determining a center point of the first mark and a center point of the second mark; connecting the center point of the first mark and the center point of the second mark to obtain a mark center point connecting line; and determining the included angle between the extension line of the connecting line of the mark central points and the horizontal direction of the measurement coordinate system as the placing angle of the target wafer.
Optionally, the target wafer includes a plurality of wafers, and the method further includes: sequentially placing a plurality of target wafers into a wafer bearing platform of a wafer loading repeatability detection system; aiming at each target wafer placed in the wafer bearing platform, determining the current position and the placing angle of the central point of the target wafer; and determining whether the positioning precision of the wafer transmission system meets the precision requirement or not based on the current positions and the placing angles of the central points of the target wafers.
Optionally, determining whether the positioning accuracy of the wafer transmission system meets the accuracy requirement based on the current positions of the central points and the placing angles of the plurality of target wafers comprises: determining a comprehensive position deviation value and a comprehensive angle deviation value of the target wafers based on the current central point positions and the placing angles of the target wafers; determining whether the integrated location deviation value is less than a location deviation threshold; determining whether the integrated angle deviation value is less than an angle deviation threshold value; if the comprehensive position deviation value is smaller than the position deviation threshold value and the comprehensive angle deviation value is smaller than the angle deviation threshold value, determining that the positioning precision of the wafer transmission system meets the requirement; and if the comprehensive position deviation value is not smaller than the position deviation threshold value and/or the comprehensive angle deviation value is not smaller than the angle deviation threshold value, determining that the positioning accuracy of the wafer transmission system does not meet the requirement.
Optionally, determining a comprehensive position deviation value and a comprehensive angle deviation value corresponding to the plurality of target wafers based on the current central point positions and the placement angles of the plurality of target wafers includes: calculating the difference between the current position of the central point of each target wafer and the reference position of the central point to obtain a plurality of position differences; determining the average value of the position difference values as a comprehensive position deviation value; calculating the difference between the respective placing angles of the target wafers and the reference angle to obtain a plurality of angle differences; and determining the average value of the plurality of angle difference values as a comprehensive angle deviation value.
In a second aspect, embodiments of the present application further provide a system for detecting wafer repeatability, the system including:
the device comprises a control unit, a first camera, a second camera and a wafer bearing platform;
the control unit executes the step of the positioning precision determination method of the wafer transmission system;
the control unit is respectively connected with the first camera and the second camera to control the first camera and the second camera;
the first camera and the second camera are positioned above the wafer bearing platform so as to photograph a target wafer on the wafer bearing platform.
In a third aspect, an embodiment of the present application further provides an electronic device, including: a processor, a memory and a bus, the memory storing machine readable instructions executable by the processor, the processor and the memory communicating via the bus when the electronic device is running, the machine readable instructions when executed by the processor performing the steps of the method for determining the positioning accuracy of a wafer transport system as described above.
In a fourth aspect, the present application further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method for determining the positioning accuracy of a wafer transport system as described above are performed.
The embodiment of the application brings the following beneficial effects:
according to the method for determining the positioning accuracy of the wafer transmission system, the first target image for the first mark pair and the second target image corresponding to the second mark can be obtained through the first camera and the second camera respectively, the current position and the placing angle of the central point of the target wafer are determined according to the first target image and the second target image, and whether the positioning accuracy of the wafer transmission system meets the accuracy requirement or not is determined according to the current position and the placing angle of the central point of the target wafer.
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.
Fig. 1 is a flowchart illustrating a method for determining a positioning accuracy of a wafer transfer system according to an embodiment of the present disclosure;
FIG. 2 is a schematic diagram illustrating an apparatus position of a system for detecting repeatability of a wafer loading according to an embodiment of the present disclosure;
FIG. 3 is a schematic structural diagram of a system for detecting repeatability of a wafer loading provided by an embodiment of the present application;
FIG. 4 is a schematic structural diagram of a control unit provided in an embodiment of the present application;
fig. 5 shows a schematic structural diagram of an electronic device provided in an embodiment of the present application.
Detailed Description
In order to make the objects, 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 with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. Every other embodiment that can be obtained by a person skilled in the art without making creative efforts based on the embodiments of the present application falls within the protection scope of the present application.
It is noted that, before the present application, with the rapid development of semiconductor technology, the critical dimension of wafer processing is gradually reduced, and the complexity of wafer processing is continuously increased, and the process requirement for the wafer is higher and higher. The process level of the wafer mainly depends on the process machining precision and the wafer transmission precision, and the wafer transmission process is completed by the wafer transmission system, so the wafer loading repeatability positioning precision of the wafer transmission system needs to be measured in order to ensure the wafer transmission precision. At present, a relatively accurate measuring method is lacked for the loading repeatability positioning precision of a wafer transmission system.
Based on this, the embodiment of the application provides a method for determining the positioning accuracy of a wafer transmission system, so as to improve the accuracy when measuring the loading repeatability positioning accuracy of the wafer transmission system.
Referring to fig. 1, fig. 1 is a flowchart illustrating a method for determining a positioning accuracy of a wafer transfer system according to an embodiment of the present disclosure. As shown in fig. 1, the method for determining the positioning accuracy of a wafer transmission system according to the embodiment of the present application is applied to a wafer loading repeatability detection system, where the wafer loading repeatability detection system includes a wafer loading platform, and the method includes:
step S101, receiving a transfer completion signal sent by a wafer transmission system that a target wafer is placed in a wafer bearing platform, and 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.
In this step, the wafer transfer system may refer to a system for transferring a wafer, and the wafer transfer system is connected to the wafer loading repeatability detection system.
The target wafer may refer to a wafer being transferred, the target wafer having a first mark and a second mark thereon.
The first mark may be a graphic mark, and the first mark is used to determine a center point position and a placing angle of the target wafer.
The second mark may refer to a graphic mark having the same shape as the first mark, and the second mark is used for positioning the center point position and the placing angle of the target wafer together with the first mark.
For example, the shape of the first mark and the second mark may be a cross, a square, or a right-angled broken line segment.
In the embodiment of the present application, the wafer transfer system may be configured according to a specified loading angle, for example: and 0 degree, placing a target wafer with a first mark and a second mark into a wafer bearing platform of a wafer loading repeatability detection system, sending a transfer completion signal to the wafer loading repeatability detection system through a network interface, turning on a light source of the wafer loading repeatability detection system after the wafer loading repeatability detection system receives the transfer completion signal sent by a wafer transmission system that the target wafer is placed into the wafer bearing platform, adjusting the brightness of the light source to an optimal value, so that the first mark and the second mark have optimal contrast in the camera view field, that is, the first mark and the second mark can be clearly seen, and then taking a picture through a camera to obtain a first target image corresponding to the first mark on the target wafer and a second target image corresponding to the second mark on the target wafer.
In an optional embodiment, the wafer-on-wafer repeatability detection system further comprises a first camera and a second camera; executing step S101 includes: and controlling the first camera to photograph the first mark on the target wafer to obtain a first target image, and simultaneously controlling the second camera to photograph the second mark on the target wafer to obtain a second target image.
Here, the number of the cameras in the wafer loading repeatability detection system is two, and the two cameras are respectively a first camera and a second camera, and the first camera is controlled to photograph the first mark and the second camera is controlled to photograph the second mark, so as to respectively obtain a first target image corresponding to the first mark and a second target image corresponding to the second mark. When the first camera and the second camera are controlled to photograph, the first camera and the second camera photograph the first marker and the second marker at the same time.
The equipment installation position of the wafer repeatability inspection system will now be described with reference to fig. 2.
Fig. 2 is a schematic diagram illustrating an apparatus position of a system for detecting repeatability of a wafer loading according to an embodiment of the present disclosure.
As shown in fig. 2, the first camera 201 and the second camera 202 are mounted above the wafer stage 206, the target wafer 205 is placed on the wafer stage 206, the first adjustment stage 203 is connected to the first camera 201, the first adjustment stage 203 is used for adjusting the position of the first camera 201 so that the first mark on the target wafer 205 is within the visual field of the first camera 201, the second adjustment stage 204 is connected to the second camera 202, the second adjustment stage 204 is used for adjusting the position of the second camera 202 so that the second mark on the target wafer 205 is within the visual field of the second camera 202, and the first adjustment stage 203 and the second adjustment stage 204 are fixed on the support 207.
Specifically, when the positioning accuracy of the wafer transport system is measured, the positions of the first adjustment stage 203 and the second adjustment stage 204 are calibrated first, so that the first camera 201 can clearly capture a first target image of the first mark and a second target image of the second mark.
Step S102, determining a current position of the first marker and a current position of the second marker based on the first target image and the second target image.
In this step, the first target image may be an image of a first mark on the target wafer captured by the pointer, and the first target image is used to determine a current position of the first mark.
The second target image may be indicative of an image taken of a second mark on the target wafer, the second target image being used to determine a current position of the second mark.
In the embodiment of the application, after the camera is controlled to photograph 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 through the first target image, and the position of the second mark can be determined through the second target image.
In an alternative embodiment, performing step S102 includes: analyzing the first target image and the second target image by using an image matching algorithm, and determining the position of a first mark and the position of a second mark in an image coordinate system; based on the conversion relation between the image coordinate system and the measurement coordinate system, converting the position of the first mark under the image coordinate system into the position of the first mark under the measurement coordinate system, and converting the position of the second mark under the image coordinate system into the position of the second mark under the measurement coordinate system; and determining the position of the first mark in the measurement coordinate system as the current position of the first mark, and determining the position of the second mark in the measurement coordinate system as the current position of the second mark.
Here, the image matching algorithm may refer to an identification algorithm for the first marker and the second marker, the image matching algorithm being used to determine the first marker from the first target image and identify the second marker from the second target image.
The image coordinate system may refer to a coordinate system established for the first camera and the second camera, the unit of the image coordinate system is a pixel, and the image coordinate system includes a first image coordinate system and a second image coordinate system.
The first image coordinate system is used for determining the position of the first mark under the image coordinate system, and the origin of the first image coordinate system is positioned at the upper left corner of the first camera photosensitive unit.
The second image coordinate system is used for determining the position of the second mark in the image coordinate system, and the origin of the second image coordinate system is at the upper left corner of the second camera photosensitive unit.
The measurement coordinate system may refer to a rectangular plane coordinate system, the unit of the measurement coordinate system is millimeter, and the origin of the measurement coordinate system may be any position of the plane of the upper surface of the support, for example: the support can be arranged at the middle position of the first adjusting platform and the second adjusting platform on the plane of the upper surface of the support, the abscissa axis of the measuring coordinate system is parallel to the horizontal side of the upper surface of the support, the ordinate axis of the measuring coordinate system is parallel to the vertical side of the upper surface of the support, wherein the upper surface of the support is rectangular, the horizontal sides of the upper surface of the support refer to two sides of the support with longer length, and the vertical sides of the upper surface of the support refer to two sides of the support with shorter length.
Specifically, after the image coordinate system is established, the transformation relationship between the image coordinate system and the measurement coordinate system, that is, the position coordinates of the coordinates of each point in the image coordinate system in the measurement coordinate system, may be determined according to the position of the origin of the image coordinate system in the measurement coordinate system and the size transformation relationship between the image coordinate system and the measurement coordinate system. The size conversion relationship between the image coordinate system and the measurement coordinate system can refer to the millimeter equivalent to 1 pixel.
In this way, after the first target image and the second target image are acquired, the position coordinates of the first mark and the second mark in the image coordinate system can be determined respectively, and then the position coordinates of the first mark and the second mark in the measurement coordinate system can be determined according to the conversion relation between the image coordinate system and the measurement coordinate system.
Step S103, based on the current position of the first mark and the current position of the second mark, determining the current position and the placement angle of the center point of the target wafer by using the position relationship among the first mark, the second mark and the reference position of the center point of the target wafer.
In this step, the reference position may refer to a position where no position deviation occurs after the wafer transmission system transmits the target wafer, the reference position is used to determine the current position and the placement angle of the center point of the target wafer, and the reference position is a coordinate position in the measurement coordinate system.
In the embodiment of the present invention, after determining the current position of the first mark and the current position of the second mark, the current position and the placing angle of the center point of the target wafer may be calculated according to the position relationship among the reference positions of the first mark, the second mark and the center point of the target wafer.
In an alternative embodiment, step S103 is performed: determining the current position of the central point of the target wafer by utilizing the position relationship among the reference position of the first mark, the reference position of the second mark and the reference position of the central point of the target wafer based on the current position of the first mark and the current position of the second mark; determining a center point of the first mark and a center point of the second mark; connecting the center point of the first mark and the center point of the second mark to obtain a mark center point connecting line; and determining the included angle between the extension line of the connecting line of the mark central points and the horizontal direction of the measurement coordinate system as the placing angle of the target wafer.
Here, the current position of the center point of the target wafer may be determined first according to the positions of the first mark and the second mark, and then the placing angle of the target wafer may be determined, or the placing angle of the target wafer may be determined first, and then the current position of the center point of the target wafer may be determined. The position relation among the first mark, the second mark and the reference position of the target wafer center point can be determined by the following method: the reference position coordinates of the three are given, for example: the reference position of the first mark is [ 10, 10 ], the reference position of the second mark is [ 10, 10 ], and the reference position of the center point of the target wafer is [ 0, 1 ], so that the position relationship of the first mark, the second mark and the target wafer can be determined by the following two formulas: X1-X0+ X2-X0 is 0, and Y1-Y0+ Y2-Y0 is 18, where X1 denotes an abscissa of a reference position of the first mark, Y1 denotes an ordinate of the reference position of the first mark, X2 denotes an abscissa of a reference position of the second mark, Y2 denotes an ordinate of the reference position of the second mark, X0 denotes an abscissa of a reference position of a center point of the target wafer, and Y0 denotes an ordinate of the reference position of the center point of the target wafer. Thus, when the current position of the first mark is [ 9, 10 ] and the current position of the second mark is [ 11, 10 ], the current position of the center point of the target wafer can be calculated to be [ 1, 1 ] by using the two calculation formulas.
The placing angle of the target wafer can also be determined according to the positions of the first mark and the second mark. Specifically, the center point of the first mark and the center point of the second mark are determined according to the shapes of the first mark and the second mark, taking the first mark and the second mark as a cross as an example, the center points of the first mark and the second mark are at the intersection point of the cross, then the center point of the first mark is connected with the center point of the second mark, and an included angle between an extension line of the connection line and the horizontal direction of the measurement coordinate system is determined as a placing angle of the target wafer, wherein the included angle is actually an included angle between the extension line and a horizontal line passing through the first mark and being parallel to the abscissa axis, and the center point of the first mark is used as a vertex of the included angle, so that the rotation direction can be determined through the positive and the negative of the included angle.
And step S104, comparing the current position of the central point of the target wafer with the reference position of the central point and the placing angle with the reference angle respectively, and determining whether the positioning accuracy of the wafer transmission system meets the accuracy requirement.
In this step, the accuracy requirement may refer to a requirement for a current position and a placement angle of a center point of the target wafer, and the accuracy requirement is used to evaluate the positioning accuracy of the wafer transmission system.
In the embodiment of the application, the current position of the central point of the target wafer is compared with the reference position of the central point, the placing angle is compared with the reference angle, and whether the positioning accuracy of the wafer transmission system meets the accuracy requirement or not can be determined according to the comparison result. For example: and if the difference value between the current position of the central point of the target wafer and the reference position of the central point is smaller than a set threshold value, and the difference value between the placing angle and the reference angle is smaller than the set threshold value, determining that the positioning precision of the wafer transmission system meets the precision requirement.
In an alternative embodiment, the target wafer includes a plurality of wafers, and the method further includes: sequentially placing a plurality of target wafers into a wafer bearing platform of a wafer loading repeatability detection system; aiming at each target wafer placed in the wafer bearing platform, determining the current position and the placing angle of the central point of the target wafer; and determining whether the positioning precision of the wafer transmission system meets the precision requirement or not based on the current positions and the placing angles of the central points of the target wafers.
And determining whether the positioning accuracy of the wafer transmission system meets the accuracy requirement or not through the current central point position and the placing angle of each of the plurality of target wafers, wherein the wafer transmission system sequentially places a single target wafer of the plurality of target wafers on a wafer bearing platform of the wafer loading repeatability detection system, the wafer loading repeatability detection system sequentially determines the current central point position and the placing angle of each target wafer, and determines whether the positioning accuracy of the wafer transmission system meets the accuracy requirement or not according to the current central point position and the placing angle of each target wafer.
In an optional embodiment, determining whether the positioning accuracy of the wafer transport system meets the accuracy requirement based on the current positions and the placing angles of the central points of the target wafers comprises: determining a comprehensive position deviation value and a comprehensive angle deviation value of the target wafers based on the current positions and the placing angles of the central points of the target wafers; determining whether the integrated location deviation value is less than a location deviation threshold; determining whether the integrated angle deviation value is less than an angle deviation threshold value; if the comprehensive position deviation value is smaller than the position deviation threshold value and the comprehensive angle deviation value is smaller than the angle deviation threshold value, determining that the positioning precision of the wafer transmission system meets the requirement; and if the comprehensive position deviation value is not smaller than the position deviation threshold value and/or the comprehensive angle deviation value is not smaller than the angle deviation threshold value, determining that the positioning accuracy of the wafer transmission system does not meet the requirement.
Here, the integrated location deviation value may refer to a location target value of a plurality of location deviation values, the integrated location deviation value being used to determine an overall deviation scenario of the plurality of location deviation values, and the target location target value may include, but is not limited to, any of the following, by way of example: a mean value, a maximum value, and a minimum value of the plurality of position deviation values.
The integrated angle deviation value may refer to an angle target value for the plurality of angle deviation values, the integrated angle deviation value being used to determine an overall deviation scenario for the plurality of angle deviation values, and exemplary, the angle target value includes, but is not limited to, any of: and the average value, the maximum value and the minimum value of the angle deviation values.
The location deviation threshold may refer to a maximum value of location deviation that meets the location accuracy requirement, and the location deviation threshold is used to determine whether the integrated location deviation value does not meet the location accuracy requirement.
The angular deviation threshold may refer to a maximum value of angular deviation that satisfies the angular accuracy requirement, and the angular deviation threshold is used to determine whether the composite angular deviation value does not satisfy the angular accuracy requirement.
Specifically, whether the comprehensive position deviation value is smaller than a position deviation threshold value and whether the comprehensive angle deviation value is smaller than an angle deviation threshold value are respectively determined, if the comprehensive position deviation value is smaller than the position deviation threshold value and the comprehensive angle deviation value is smaller than the angle deviation threshold value, it is determined that the positioning accuracy of the wafer transmission system meets the requirement, and if one of the comprehensive position deviation value and the comprehensive angle deviation value is not smaller than the corresponding deviation threshold value, it is determined that the positioning accuracy of the wafer transmission system does not meet the requirement. Wherein the position deviation threshold and the angle deviation threshold are determined empirically or according to process requirements.
In an optional embodiment, determining a comprehensive position deviation value and a comprehensive angle deviation value corresponding to a plurality of target wafers based on the current central point positions and the placement angles of the target wafers includes: calculating the difference between the current position of the central point of each target wafer and the reference position of the central point to obtain a plurality of position differences; determining the average value of the position difference values as a comprehensive position deviation value; calculating the difference between the respective placing angles of the target wafers and the reference angle to obtain a plurality of angle differences; and determining the average value of the plurality of angle difference values as a comprehensive angle deviation value.
The difference between the current position of the center point of each target wafer and the reference position of the center point is calculated, and then the deviation between the center positions of the plurality of target wafers and the reference position is represented by the size of the mean value of the difference values of the plurality of positions, wherein the larger the mean value of the difference values of the positions indicates that the position deviation is larger and the precision is lower, and the smaller the mean value of the difference values of the positions indicates that the position deviation is smaller and the precision is higher. Calculating a difference value between the placing angle of each target wafer and the reference angle, and then representing the deviation between the placing angle and the reference angle of the target wafers by using the average value of the angle difference values, wherein the larger the average value of the angle difference values is, the larger the angle deviation is, the lower the precision is, and the smaller the average value of the angle difference values is, the smaller the angle deviation is, the higher the precision is.
Compared with the positioning accuracy determining method of the wafer transmission system in the prior art, the method can respectively acquire the first target image for the first mark pair and the second target image corresponding to the second mark through the first camera and the second camera, and determining the current position and the placing angle of the central point of the target wafer according to the first target image and the second target image, so as to determine whether the positioning accuracy of the wafer transmission system meets the accuracy requirement according to the current position and the placing angle of the central point of the target wafer, meanwhile, by determining the comprehensive position deviation value and the comprehensive angle deviation value of a plurality of target wafers, the positioning precision of the wafer transmission system is repeatedly measured, the positioning precision of the wafer transmission system can be more accurately determined, and the problem that the loading repeated positioning precision of the wafer transmission system cannot be accurately measured is solved.
Based on the same inventive concept, the embodiment of the present application further provides a wafer loading repeatability detection system corresponding to the method for determining the positioning accuracy of the wafer transmission system, and as the principle of solving the problem of the system in the embodiment of the present application is similar to the method for determining the positioning accuracy of the wafer transmission system in the embodiment of the present application, the implementation of the system can refer to the implementation of the method, and repeated details are omitted.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a wafer repeatability inspection system according to an embodiment of the present disclosure. As shown in fig. 3, the system 300 for detecting repeatability of wafer loading includes:
a control unit 310, a first camera 320, a second camera 330, and a wafer stage (not shown);
the control unit executes the steps of the positioning accuracy determination method such as a wafer transmission system;
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;
the first camera 320 and the second camera 330 are located above the wafer stage for taking pictures of target wafers on the wafer stage.
The wafer bearing platform is used for bearing a target wafer.
The system 300 further includes a light source (not shown), and the control unit 310 is connected to the light source for adjusting the brightness of the light source to achieve an optimal contrast of the marks on the target wafer in the field of view of the camera.
The wafer loading repeatability inspection system 300 further includes a first adjustment stage (not shown) for adjusting the position of the first camera 320 and a second adjustment stage (not shown) for adjusting the position of the second camera 330, such that the first mark on the target wafer is under the field of view of the first camera 320 and the second mark is under the field of view of the second camera 330.
The control unit 310 is described below.
Fig. 4 shows a schematic structural diagram of a control unit provided in an embodiment of the present application.
As shown in fig. 4, 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.
The camera control subunit 311 may refer to a camera control software library, and is configured to set camera parameters, control a camera to photograph and transmit an image, where the setting of the camera parameters includes: the exposure time of the camera and the camera gain are set.
The database subunit 312 is used to maintain various information for the repeatability tests of the loading, including: the method comprises the steps of extracting image parameters of a first mark and a second mark on a target wafer according to the relative position relationship between the first mark and the second mark on the target wafer, the position relationship among the first mark, the second mark and the central point of the target wafer, and the conversion relationship between an image coordinate system and a measurement coordinate system, wherein the position relationship among the first mark, the second mark and the central point of the target wafer comprises the distance and the angle between the central point of the target wafer and the first mark, and the distance and the angle between the central point of the target wafer and the second mark.
The light source control subunit 313 may refer to a light source control software library for controlling the optical switch and setting the brightness of the light source.
The image algorithm subunit 314 may refer to an image algorithm software library, which is configured to locate the positions of the first mark and the second mark on the target wafer through an image processing algorithm, and calculate the current position of the center point of the target wafer according to the positional relationship among the first mark, the second mark, and the center point of the target wafer. And obtaining the difference value between the current position of the central point of each target wafer and the reference position of the central point and the difference value between the placing angle of each target wafer and the reference angle through repeated measurement, and further calculating the comprehensive position deviation value and the comprehensive angle deviation value of the plurality of target wafers.
The transmission system communication subunit 315 may refer to a software library for communicating with the wafer transmission system, and the transmission system communication subunit 315 communicates with the wafer transmission system through a network interface to obtain a wafer loading completion signal.
The data recording subunit 316 may refer to a data recording software library for recording data obtained by each calculation, where the data at least includes the position coordinates of the central point of the target wafer and the placement angle of the target wafer.
Referring to fig. 5, fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure. As shown in fig. 5, the electronic device 400 includes a processor 410, a memory 420, and a bus 430.
The memory 420 stores machine-readable instructions executable by the processor 410, when the electronic device 400 runs, the processor 410 communicates with the memory 420 through the bus 430, and when the machine-readable instructions are executed by the processor 410, the steps of the method for determining the positioning accuracy of the wafer transport system in the method embodiment shown in fig. 1 may be executed.
An embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the step of the method for determining the positioning accuracy of the wafer transmission system in the embodiment of the method shown in fig. 1 may be executed.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. The above-described apparatus embodiments are merely illustrative, and for example, the division of the units into only one type of logical function may be implemented in other ways, and for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not implemented. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
The functions, if implemented in software functional units and sold or used as a stand-alone product, may be stored in a non-transitory computer-readable storage medium executable by a processor. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present application, and are used for illustrating the technical solutions of the present application, but not limiting the same, and the scope of the present application is not limited thereto, and although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: those skilled in the art can still make modifications or changes to the embodiments described in the foregoing embodiments, or make equivalent substitutions for some features, within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the exemplary embodiments of the present application, and are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (10)
1. A method for determining the positioning accuracy of a wafer transmission system is characterized in that the method is applied to a wafer loading repeatability detection system, the wafer loading repeatability detection system comprises a wafer bearing platform, and the method comprises the following steps:
receiving a transfer completion signal sent by a wafer transmission system that a target wafer is placed in the wafer bearing platform, and 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;
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;
determining the current position and the placing angle of the central point of the target wafer by utilizing the position relation among the reference positions of the first mark, the second mark and the central point of the target wafer based on the current position of the first mark and the current position of the second mark;
and respectively comparing the current position of the central point of the target wafer with the reference position of the central point and the placing angle with the reference angle, and determining whether the positioning precision of the wafer transmission system meets the precision requirement.
2. The method of claim 1, wherein the system for detecting repeatability of wafer loading further comprises a first camera and a second camera;
the 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 includes:
and controlling the first camera to photograph the first mark on the target wafer to obtain a first target image, and simultaneously controlling the second camera to photograph the second mark on the target wafer to obtain a second target image.
3. The method of claim 1, wherein 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 comprises:
analyzing the first target image and the second target image by using an image matching algorithm, and determining the position of a first mark and the position of a second mark in an image coordinate system;
based on the conversion relation between the image coordinate system and the measurement coordinate system, converting the position of the first mark under the image coordinate system into the position of the first mark under the measurement coordinate system, and converting the position of the second mark under the image coordinate system into the position of the second mark under the measurement coordinate system;
and determining the position of the first mark in the measurement coordinate system as the current position of the first mark, and determining the position of the second mark in the measurement coordinate system as the current position of the second mark.
4. The method of claim 1, wherein determining the current position and the placing angle of the center point of the target wafer based on the current position of the first mark and the current position of the second mark by using the positional relationship among the first mark, the second mark and the reference position of the center point of the target wafer comprises:
determining the current position of the central point of the target wafer by utilizing the position relationship among the reference position of the first mark, the reference position of the second mark and the reference position of the central point of the target wafer based on the current positions of the first mark and the second mark;
determining a center point of the first mark and a center point of the second mark;
connecting the center point of the first mark and the center point of the second mark to obtain a mark center point connecting line;
and determining the included angle between the extension line of the connecting line of the mark central points and the horizontal direction of the measurement coordinate system as the placing angle of the target wafer.
5. The method of claim 1, wherein the target wafer comprises a plurality, the method further comprising:
sequentially placing a plurality of target wafers into a wafer bearing platform of a wafer loading repeatability detection system;
aiming at each target wafer placed in the wafer bearing platform, determining the current position and the placing angle of the central point of the target wafer;
and determining whether the positioning precision of the wafer transmission system meets the precision requirement or not based on the current positions and the placing angles of the central points of the target wafers.
6. The method of claim 5, wherein determining whether the positioning accuracy of the wafer transport system meets the accuracy requirement based on the current position and the placing angle of the center points of the plurality of target wafers comprises:
determining a comprehensive position deviation value and a comprehensive angle deviation value of the target wafers based on the current positions and the placing angles of the central points of the target wafers;
determining whether the integrated location deviation value is less than a location deviation threshold;
determining whether the integrated angle deviation value is less than an angle deviation threshold;
if the comprehensive position deviation value is smaller than a position deviation threshold value and the comprehensive angle deviation value is smaller than an angle deviation threshold value, determining that the positioning precision of the wafer transmission system meets the requirement;
and if the comprehensive position deviation value is not smaller than the position deviation threshold value and/or the comprehensive angle deviation value is not smaller than the angle deviation threshold value, determining that the positioning precision of the wafer transmission system does not meet the requirement.
7. The method of claim 6, wherein determining a composite position deviation value and a composite angle deviation value for the plurality of target wafers based on the current center point position and the placement angle of each of the plurality of target wafers comprises:
calculating the difference between the current position of the central point of each target wafer and the reference position of the central point to obtain a plurality of position differences;
determining the average value of the position difference values as a comprehensive position deviation value;
calculating the difference between the respective placing angles of the target wafers and the reference angle to obtain a plurality of angle differences;
and determining the average value of the plurality of angle difference values as a comprehensive angle deviation value.
8. A system for detecting wafer repeatability, the system comprising: the system comprises a control unit, a first camera, a second camera and a wafer bearing platform;
the control unit executing the steps of the method for determining the positioning accuracy of a wafer transfer system according to any one of claims 1 to 7;
the control unit is respectively connected with the first camera and the second camera so as to control the first camera and the second camera;
the first camera and the second camera are positioned above the wafer bearing platform so as to photograph a target wafer on the wafer bearing platform.
9. An electronic device, comprising: a processor, a storage medium and a bus, the storage medium storing machine-readable instructions executable by the processor, the processor and the storage medium communicating via the bus when the electronic device is running, the processor executing the machine-readable instructions to perform the steps of the method for determining the positioning accuracy of a wafer transport system as claimed in any one of claims 1 to 7.
10. A computer-readable storage medium, having stored thereon a computer program which, when being executed by a processor, is adapted to carry out the steps of the method of determining the positioning accuracy of a wafer transport system as claimed in any one of claims 1 to 7.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116092984A (en) * | 2023-03-06 | 2023-05-09 | 睿励科学仪器（上海）有限公司 | Method for determining the positioning accuracy of a wafer transport device |
| CN116902559A (en) * | 2023-08-23 | 2023-10-20 | 中科微至科技股份有限公司 | Visual positioning correction method for conveying sheet-like object |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116092984A (en) * | 2023-03-06 | 2023-05-09 | 睿励科学仪器（上海）有限公司 | Method for determining the positioning accuracy of a wafer transport device |
| CN116902559A (en) * | 2023-08-23 | 2023-10-20 | 中科微至科技股份有限公司 | Visual positioning correction method for conveying sheet-like object |
| CN116902559B (en) * | 2023-08-23 | 2024-03-26 | 中科微至科技股份有限公司 | Visual positioning correction method for conveying sheet-like object |
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