A method and device for detecting the placement status of wafers in a wafer box

Abstract

The present invention provides a detection method and device for the placement state of wafers in a wafer box, which is applied to the detection of wafer boxes. The detection method includes: obtaining the standard value of the thickness and the standard value of the angle of the wafer; using a laser and a camera to scan the wafer box to obtain the three-dimensional morphology of the wafer box; according to the three-dimensional morphology, using a thickness calculation algorithm and an angle calculation algorithm to calculate the thickness and angle of each wafer in the wafer box; wherein the thickness calculation algorithm processes the data of the three-dimensional morphology through a point cloud downsampling method and a point cloud clustering method; comparing the thickness and angle of each wafer in the wafer box with the standard value of the thickness and the standard value of the angle to determine whether there are duplicate wafers, oblique wafers, and missing wafers in the wafer box. The present invention solves the technical problem that the traditional Mapping operation needs to use a ranging sensor to scan the inside of the wafer box point by point to determine the wafer position, resulting in a long scanning time and affecting production efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method and device for detecting the placement status of wafers in a wafer box. Background Art

[0002] In the field of semiconductor manufacturing, the mapping operation usually refers to the process of detecting and confirming the position of the wafer in the semiconductor equipment. The core of this operation is to scan the specific position of the wafer in the wafer box to ensure that the equipment can operate the wafer correctly. However, the traditional mapping operation uses a ranging sensor to scan the inside of the wafer box and calculates the returned data to determine the wafer position. This method can only receive data but cannot form an image, and the scanning time is long.

[0003] Existing problems: Traditional mapping operations require the use of ranging sensors to scan the inside of the wafer box point by point to determine the wafer position, resulting in a long scanning time and affecting production efficiency. Summary of the invention

[0004] The present invention solves the technical problem that the traditional Mapping operation requires the use of a distance measuring sensor to scan the inside of the wafer box point by point to determine the wafer position, resulting in a long scanning time and affecting production efficiency. The present invention uses a laser and a camera to scan the wafer box to obtain the three-dimensional morphology of the wafer box, thereby calculating the thickness and angle of each wafer in the wafer box, which effectively shortens the scanning time and improves production efficiency.

[0005] To solve the above problems, the present invention provides a method for detecting the placement status of wafers in a wafer box, which is applied to the detection of the wafer box, and the detection method comprises: obtaining a standard value of thickness and a standard value of angle of the wafer; scanning the wafer box with a laser and a camera to obtain a three-dimensional morphology of the wafer box; calculating the thickness and angle of each wafer in the wafer box according to the three-dimensional morphology using a thickness calculation algorithm and an angle calculation algorithm; wherein the thickness calculation algorithm processes the data of the three-dimensional morphology by a point cloud downsampling method and a point cloud clustering method; comparing the thickness and angle of each wafer in the wafer box with the standard value of thickness and the standard value of angle to determine whether there are duplicate wafers, skewed wafers, and missing wafers in the wafer box.

[0006] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: by scanning the wafer box with a laser and a camera, the three-dimensional morphology of the wafer box can be quickly obtained, avoiding the time-consuming process of scanning point by point, thereby significantly shortening the detection time and improving production efficiency. By analyzing the three-dimensional morphology using the thickness calculation algorithm and the angle calculation algorithm, the thickness and angle of each wafer in the wafer box can be accurately calculated, which is more accurate and reliable than the traditional method. By comparing the thickness and angle of each wafer in the wafer box with the thickness standard value and the angle standard value, problems in the wafer box, such as duplicate wafers, skewed wafers and missing wafers, can be discovered in time, which is conducive to timely adjustment of the production process and improvement of product quality. The entire detection process can be automated, reducing manual intervention, reducing the possibility of human error, and improving the degree of automation of detection.

[0007] In a possible design, the standard thickness value and the standard angle value of the wafer are obtained, including: obtaining a standard wafer box in which all wafers are normally placed, using a laser and a camera to scan and establish the three-dimensional morphology of the standard wafer box; according to the three-dimensional morphology of the standard wafer box, using a thickness calculation algorithm and an angle calculation algorithm to calculate the standard thickness value and the standard angle value.

[0008] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: by obtaining the thickness standard value and angle standard value of the standard wafer box, a standardized detection reference can be established to help the detection device achieve a more unified and standardized detection process and improve the stability of product quality. The three-dimensional morphology standard of the wafer box is established, which can quickly and accurately detect and analyze the wafer, saving detection time and improving production efficiency.

[0009] In one possible design, a laser and a camera are used to scan a wafer box, including: the laser emits laser light toward the wafer box, and after the laser light is reflected by the arc edge of the wafer, it is focused by the lens of the camera on an imaging plane to form a two-dimensional image of the arc edge of the wafer; wherein the light plane formed by the laser light emitted by the laser is parallel to the wafer in the wafer box, the focus of the camera is on the light plane, and the imaging plane is perpendicular to the light plane.

[0010] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the light plane formed by the laser emitted by the laser is parallel to the wafer in the wafer box, and the focus of the camera is on the light plane, which can achieve more precise imaging and improve the detection precision and accuracy of the arc edge of the wafer. The coordinated use of the laser and the camera can realize a fast scanning process, improve the scanning speed, and facilitate efficient detection and analysis in the detection system. The design of the imaging plane being perpendicular to the light plane can reduce the possibility of optical distortion, ensure the accuracy and stability of the imaging, and help improve the reliability of data acquisition. The two-dimensional image obtained by scanning with the laser and the camera can intuitively display the morphological characteristics of the arc edge of the wafer.

[0011] In a possible design, the laser and the camera are driven by a mobile device, moving in the z direction and scanning the wafer box; the three-dimensional morphology of the wafer box is obtained, including: the camera collects two-dimensional images of the arc edges of the wafers in the wafer box in the x and y directions, and obtains the height of the mobile device in the z direction in real time to obtain the three-dimensional information of the wafer at this height; the laser and the camera are driven by the mobile device to move in the z direction to obtain the three-dimensional information of each wafer in the wafer box; the three-dimensional information of each wafer in the wafer box is spliced ​​to obtain the three-dimensional morphology of the wafer box.

[0012] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by driving the laser and camera to move in the z direction through a mobile device, the three-dimensional information of each wafer in the wafer box can be obtained, including the two-dimensional image of the arc edge in the x and y directions and the height information in the z direction, thereby realizing the acquisition of comprehensive three-dimensional morphological information of each wafer inside the wafer box. By splicing the three-dimensional information of each wafer in the wafer box, the three-dimensional morphology of the entire wafer box can be reconstructed, thereby improving the accuracy and comprehensiveness of the analysis and evaluation of the overall morphology of the wafer box. By driving the laser and camera to move in the z direction through a mobile device, rapid scanning and three-dimensional information acquisition of each wafer inside the wafer box can be realized, thereby improving the efficiency and accuracy of wafer box detection in the detection system.

[0013] In one possible design, the thickness calculation algorithm processes the three-dimensional topography data through point cloud downsampling and point cloud clustering methods, and projects it into a two-dimensional plane, and uses the rotating calcanelle method in the two-dimensional plane to determine the thickness of each wafer in the wafer box.

[0014] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: through the point cloud downsampling method and the point cloud clustering method, a large amount of three-dimensional morphology data can be effectively processed, the surface point cloud data of each wafer in the wafer box can be extracted, and the thickness of the wafer can be calculated by the rotating caliper method, thereby realizing the accurate calculation of the wafer thickness. The point cloud downsampling method and the point cloud clustering method can be used to efficiently process large-scale three-dimensional morphology data, reduce the complexity and amount of calculation of data processing, and improve the calculation efficiency and accuracy. At the same time, the rotating caliper method can be used to comprehensively analyze the thickness of the wafer, which helps to accurately determine the thickness of each wafer in the wafer box.

[0015] In a possible design, the thickness calculation algorithm includes: using a point cloud downsampling method to perform a thinning operation on the three-dimensional morphology data to reduce the amount of data; using a point cloud clustering method to separate the arc edge morphology of different wafers in the three-dimensional morphology to obtain the arc edge morphology of wafers at different positions; according to the arc edge morphology of each wafer, project it onto the x, z plane to convert it into a two-dimensional plane, and use the rotating calcanelle method in the two-dimensional plane to calculate the minimum circumscribed rectangle of each wafer, wherein the short side of the minimum circumscribed rectangle is the thickness of the wafer.

[0016] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by separating the arc edge morphology of different wafers in the three-dimensional morphology, the morphology information of wafers at different positions can be obtained. By combining the point cloud downsampling method and the point cloud clustering method, the three-dimensional morphology data can be processed and analyzed more quickly, reducing the computing time and resource consumption, and improving the computing efficiency. The rotating caliper method is used to calculate the minimum circumscribed rectangle of each wafer to determine the thickness of each wafer, which can more accurately determine the thickness information of the wafer and avoid the calculation error caused by the complex shape in the traditional method.

[0017] In a possible design, the angle calculation algorithm includes: using the results of the point cloud clustering method of the thickness calculation algorithm to project the three-dimensional point cloud of the arc edge morphology of each wafer onto the x, y plane to convert it into a two-dimensional plane; in the two-dimensional plane, for each wafer arc edge morphology, extracting the points with the maximum y value in the x direction, and forming these points into a top point set; based on the top point set, fitting the points in the set by the least squares method to obtain a straight line equation; wherein the angle between the straight line of the straight line equation and the x direction is the angle of the wafer.

[0018] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: by projecting the three-dimensional point cloud onto a two-dimensional plane and using the top point set for straight line fitting, the angle of the wafer can be calculated more accurately, avoiding the angle calculation error caused by inaccurate point cloud data processing in the traditional method. The least squares method is used to fit the point set, which can reduce the impact of data noise on angle calculation and improve the stability and reliability of angle measurement.

[0019] In one possible design, a laser and a camera are used to scan a wafer box, including: the laser emits laser light toward the wafer box, and after the laser light is reflected by the arc edge of the wafer, it is focused by the camera lens on an imaging plane to form an image of the arc edge of the wafer; wherein the light plane formed by the laser light emitted by the laser is perpendicular to the wafers in the wafer box, and the imaging plane is perpendicular to the wafers in the wafer box.

[0020] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: Since the light plane is perpendicular to the wafer, the projection of the laser on the wafer surface can be ensured to be accurate, thereby achieving accurate measurement of parameters such as wafer size and shape. The light plane is perpendicular to the wafer, which can reduce the error caused by the projection angle and improve the accuracy and reliability of the measurement. The imaging plane is perpendicular to the wafer, which can avoid deformation caused by perspective, ensure the authenticity of the imaging, and facilitate accurate analysis of the characteristics of the wafer surface.

[0021] In a possible design, the laser and the camera are driven by a mobile device to rotate or translate in the z direction to scan the wafer box; the three-dimensional morphology of the wafer box is obtained, including: the camera collects the arc edge points of the arc edge of the wafer in the wafer box in the x and z directions; the laser and the camera are driven by the mobile device to rotate and obtain the arc edge points at different x positions; the arc edge points of each wafer in the wafer box are spliced ​​to obtain the arc edge morphology; the mobile device changes its position in the z direction after one rotation; the arc edge morphologies of the wafer box at various positions in the z direction are spliced ​​to obtain the three-dimensional morphology of the wafer box.

[0022] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: by driving the rotation of the laser and the camera through the mobile device, the three-dimensional morphology of the wafer box can be efficiently obtained, including the points of the arc edge of the wafer in different directions, realizing the comprehensive collection of the morphology of the wafer box. By splicing the arc edge points at different positions, the arc edge morphology of each wafer in the wafer box can be accurately spliced ​​to obtain the overall three-dimensional morphology data, which is helpful for a comprehensive analysis of the structure and characteristics of the wafer box. By splicing the arc edge morphology of each position of the wafer box in the z direction, the full-dimensional three-dimensional morphology of the wafer box can be obtained, showing the overall structure and characteristics of the wafer box, which helps to understand the morphology of the wafer box more comprehensively.

[0023] The present invention also provides a device for detecting the placement status of wafers in a wafer box, which implements a method for detecting the placement status of wafers in a wafer box. The detection device includes a laser and a camera; wherein the laser is a line laser and the camera is an area array camera; the line laser is used to emit a laser beam, and the area array camera is used to capture the reflected image after the laser is irradiated to the arc edge of each wafer in the wafer box.

[0024] Compared with the prior art, the technical effect achieved by adopting this technical scheme is as follows: the detection device for the wafer placement status in a wafer box of the present invention realizes the detection method for the wafer placement status in a wafer box of any technical scheme of the present invention. Therefore, it has all the beneficial effects of the detection method for the wafer placement status in a wafer box of any technical scheme of the present invention, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1A flow chart of a method for detecting the placement status of wafers in a wafer box provided by an embodiment of the present invention;

[0026] Figure 2 A flowchart of a thickness calculation algorithm provided by an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of a two-dimensional plane of wafer thickness provided in an embodiment of the present invention Figure 1 ;

[0028] Figure 4 A schematic diagram of a two-dimensional plane of wafer thickness provided in an embodiment of the present invention Figure 2 ;

[0029] Figure 5 A schematic diagram of a two-dimensional plane of wafer angles provided by an embodiment of the present invention;

[0030] Figure 6 A structural diagram of the laser and camera provided in Example 1;

[0031] Figure 7 This is a schematic diagram of imaging of the laser and camera provided in Example 1;

[0032] Figure 8 An execution flow chart of obtaining the three-dimensional topography of a wafer box provided in Example 1;

[0033] Fig. 9 A schematic diagram of the activities of the laser and camera provided in Example 1;

[0034] Fig.10 A structural diagram of a laser and a camera provided in Example 2;

[0035] Fig.11 This is a schematic diagram of imaging of the laser and camera provided in Example 2;

[0036] Fig.12 An execution flow chart of obtaining the three-dimensional topography of a wafer box provided in Example 2;

[0037] Fig.13 A schematic diagram of the activities of the laser and camera provided in Example 2;

[0038] Fig.14 A schematic diagram of the structure of a detection device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0040] See also Figures 1 to 13The present embodiment provides a method for detecting the placement status of wafers in a wafer box, which is applied to the detection of wafer boxes. The detection method includes: obtaining a thickness standard value and an angle standard value of the wafer; scanning the wafer box with a laser and a camera to obtain a three-dimensional shape of the wafer box; calculating the thickness and angle of each wafer in the wafer box according to the three-dimensional shape using a thickness calculation algorithm and an angle calculation algorithm; wherein the thickness calculation algorithm processes the three-dimensional shape data by a point cloud downsampling method and a point cloud clustering method; comparing the thickness and angle of each wafer in the wafer box with the thickness standard value and the angle standard value to determine whether there are duplicate wafers, skew wafers, or missing wafers in the wafer box.

[0041] Specifically, in the field of semiconductor manufacturing, mapping operations refer to scanning and identifying various features, structures or components on the wafer to establish a correspondence between the spatial coordinates and features of each position on the wafer. This process usually involves scanning the wafer using optical or other sensor technologies, and then comparing the scanned information with the model pre-established by the device to determine the specific features and structures of each position on the wafer. In this embodiment, a self-developed line laser sensor composed of a line light source and an industrial camera is used to scan the position of the wafer in the wafer box to generate a three-dimensional point cloud image, which can achieve visualization and improve efficiency. Among them, a three-dimensional point cloud image is a data structure used to represent the surface or scene of an object in a three-dimensional space. It is composed of a large number of points, each of which contains position information in three-dimensional space, that is, the values ​​of x, y, and z coordinates; these points form a point cloud according to their positional relationship in space, and the density and position of these points can be used to depict the shape, structure, and surface features of the wafer in the wafer box.

[0042] Specifically, in this embodiment, the plane formed by the x-direction and the y-direction is parallel to the plane of the wafer in the standard wafer box; wherein the y-direction is the direction in which the laser approaches or moves away from the wafer, and the x-direction is the direction perpendicular to the y-direction in the plane formed by the x-direction and the y-direction. In the wafer box, the wafers are stacked in a non-contact manner, and the stacking direction of the wafers is the z-direction, wherein the z-direction is perpendicular to the plane formed by the x-direction and the y-direction. The occurrence of heavy wafers, oblique wafers and missing wafers in the wafer box usually refers to some problems that occur during the stacking process of the wafers. Heavy wafers refer to the situation that when the wafers are stacked, there is not enough gap between some wafers, causing them to squeeze or overlap each other, which may cause damage or cracking of the surface of the wafer. Oblique wafers refer to the situation that when the wafers are stacked, due to uneven force or improper placement, the wafers are tilted relative to the bottom of the box or other wafers, which may affect the stability and stacking effect of the wafers. Missing wafers refer to the phenomenon that there are no wafers placed in certain positions in the wafer box, resulting in vacancies or missing wafers.

[0043] Furthermore, the standard thickness value and the standard angle value of the wafer are obtained, including: obtaining a standard wafer box in which all wafers are normally placed, using a laser and a camera to scan and establish a three-dimensional morphology of the standard wafer box; according to the three-dimensional morphology of the standard wafer box, using a thickness calculation algorithm and an angle calculation algorithm, calculate the standard thickness value and the standard angle value.

[0044] Specifically, the wafers in the standard wafer box are certified and meet the requirements. They can be used as reference standards to compare and verify the quality and placement of other wafers. By establishing the three-dimensional morphology of the standard wafer box, the standard value of the thickness and angle of the wafer can be obtained to help ensure the quality and stability of the wafer during the production process. The standard wafer box can be used to detect and calibrate equipment such as lasers and cameras to ensure the accuracy and reliability of their measurement results. The thickness standard value refers to the reference value of the thickness of the wafer. By measuring the thickness of the wafer and comparing it with the preset standard value, it can be evaluated whether the wafers in the wafer box overlap or are missing, forming a double wafer or missing wafer. The angle standard value refers to the reference value of the placement angle of the wafer in the wafer box. By measuring the angle of the wafer and comparing it with the preset standard value, it can be determined whether the wafer in the wafer box is tilted to form a slanted wafer.

[0045] Furthermore, the thickness calculation algorithm processes the three-dimensional morphology data through point cloud downsampling and point cloud clustering methods, and projects it into a two-dimensional plane. The rotating caliper method is used in the two-dimensional plane to determine the thickness of each wafer in the wafer box.

[0046] Specifically, point cloud downsampling method and point cloud clustering method are two commonly used methods in point cloud data processing, which are used to simplify and analyze point cloud data. Among them, the three-dimensional morphology of the wafer box is the point cloud data that needs to be processed in this embodiment. Point cloud data usually contains a large number of points, and sometimes we only need to retain a part of the points to reduce the amount of data or improve processing efficiency. The point cloud downsampling method is to select some points from the original point cloud data, retain its key features while reducing the amount of data. The points in the point cloud data may represent different objects or different parts of objects, and the point cloud clustering method aims to cluster these points together according to their characteristics to form different categories or clusters. Through point cloud clustering, we can achieve the segmentation and classification of point cloud data, so as to better understand and process point cloud data.

[0047] Furthermore, the thickness calculation algorithm includes: using the point cloud downsampling method to perform a thinning operation on the three-dimensional morphology data to reduce the amount of data; using the point cloud clustering method to separate the arc edge morphology of different wafers in the three-dimensional morphology to obtain the arc edge morphology of wafers at different positions; according to the arc edge morphology of each wafer, project it onto the x, z plane to convert it into a two-dimensional plane, and use the rotating caliper method in the two-dimensional plane to calculate the minimum circumscribed rectangle of each wafer, wherein the short side of the minimum circumscribed rectangle is the thickness of the wafer.

[0048] Specifically, see Figures 2 to 4 In this embodiment, point cloud downsampling is to perform a thinning operation on the three-dimensional shape data of the wafer box, and clustering is to separate different wafer arc edge shapes. After clustering, the wafer arc edge shapes at different positions can be obtained, and the minimum bounding rectangle calculation operation is performed on each shape. Among them, when calculating the minimum bounding rectangle, the point cloud data of the three-dimensional shape is first projected on the xz plane to form a two-dimensional plane, and the minimum bounding rectangle is calculated in the two-dimensional plane using the rotating caliper method, and the short side of the minimum bounding rectangle is the thickness of the wafer.

[0049] Furthermore, the angle calculation algorithm includes: using the results of the point cloud clustering method of the thickness calculation algorithm to project the three-dimensional point cloud of the arc edge morphology of each wafer onto the x, y plane to convert it into a two-dimensional plane; in the two-dimensional plane, for each wafer's arc edge morphology, extracting the points with the maximum y value in the x direction, and forming these points into a top point set; based on the top point set, fitting the points in the set by the least squares method to obtain a straight line equation; wherein the angle between the straight line of the straight line equation and the x direction is the angle of the wafer.

[0050] Specifically, see Figure 5 The purpose of using the least squares method in the angle calculation algorithm is to find a straight line equation that best fits the data points of the top point set by fitting these points, so as to obtain the angle of wafer placement. Specifically, the least squares method can be used to find a straight line that minimizes the sum of the squares of the distances between this straight line and the points in the top point set, that is, the best fitting effect. The straight line equation obtained in this way can well describe the distribution of the arc edge morphology of the wafer on the two-dimensional plane, and then calculate the angle of the wafer.

[0051] Embodiment 1:

[0052] See also Figures 6 to 9 This embodiment provides a method for detecting the placement status of wafers in a wafer box. In addition to the technical features of the above embodiments, this embodiment further includes the following technical features.

[0053] In this embodiment, a laser and a camera are used to scan a wafer box, including: the laser emits laser light to the wafer box, and after the laser light is reflected by the arc edge of the wafer, it is focused on an imaging plane by a camera lens to form a two-dimensional image of the arc edge of the wafer; wherein a light plane formed by the laser light emitted by the laser is parallel to the wafer in the wafer box, the focus of the camera is on the light plane, and the imaging plane is perpendicular to the light plane.

[0054] Specifically, the laser projects laser light onto the arc edge of the wafer. The light is reflected through the lens and hits the imaging plane to form an image of the light. The image formed is the arc edge of the wafer. The laser is a line laser, and the output light path is represented by a light plane. When imaging, the light plane is required to be as parallel as possible to the wafer. The camera is a planar array camera, and one imaging of the camera is recorded as one scan of the arc edge. The imaging plane of the camera is perpendicular to the light plane, and the camera focus is on the light plane. See Figure 3 , in the laser and camera imaging diagram Figure 1 In the figure, the triangular plane formed by the camera focus and the line segments on the imaging plane is coplanar with the light plane, and a row of images on the imaging plane represents a row on the arc edge of the wafer.

[0055] Furthermore, the laser and the camera are driven by a mobile device to move in the z direction and scan the wafer box; the three-dimensional morphology of the wafer box is obtained, including: the camera collects two-dimensional images of the arc edges of the wafers in the wafer box in the x and y directions, and obtains the height of the mobile device in the z direction in real time to obtain the three-dimensional information of the wafer at the height; the laser and the camera are driven by the mobile device to move in the z direction to obtain the three-dimensional information of each wafer in the wafer box; the three-dimensional information of each wafer in the wafer box is spliced ​​to obtain the three-dimensional morphology of the wafer box.

[0056] Specifically, in this embodiment, see Fig. 9 The camera acquisition result is a two-dimensional image containing information about the arc edge of the wafer in the x and y directions. By obtaining the height information of the mobile device in the z direction in real time from the mobile device, the height of each two-dimensional image in the z direction can be known. Combined with the arc edge information in the x and y directions in the two-dimensional image, the three-dimensional information of the wafer arc edge at a certain z direction position can be obtained. Among them, the wafer has thickness, that is, the arc edge of a single wafer is imaged multiple times in the z direction, and the z direction information is used to complete the splicing operation to obtain the three-dimensional morphology of the arc edge of a single wafer. After the mobile device completes the movement of a wafer box, the three-dimensional morphology of each wafer arc edge is spliced ​​to obtain the three-dimensional morphology of the entire box of wafers.

[0057] Embodiment 2:

[0058] See also Figures 10 to 13 This embodiment provides a method for detecting the placement status of wafers in a wafer box. In addition to the technical features of the above embodiments, this embodiment further includes the following technical features.

[0059] In this embodiment, a laser and a camera are used to scan a wafer box, including: the laser emits laser light to the wafer box, and after the laser light is reflected by the arc edge of the wafer, it is focused on an imaging plane by the lens of the camera to form an image of the arc edge of the wafer; wherein, the light plane formed by the laser light emitted by the laser is perpendicular to the wafers in the wafer box, and the imaging plane is perpendicular to the wafers in the wafer box.

[0060] Specifically, in this embodiment, the light plane projected by the laser is perpendicular to the wafer, the imaging plane of the area array camera is perpendicular to the wafer, and a definite positional relationship between the light plane and the imaging plane is not required.

[0061] Furthermore, the laser and the camera are driven by a mobile device to rotate or translate in the z direction to scan the wafer box; the three-dimensional morphology of the wafer box is obtained, including: the camera collects arc edge points of the arc edge of the wafer in the wafer box in the x and z directions; the laser and the camera are driven by the mobile device to rotate to obtain arc edge points at different x positions; the arc edge points of each wafer in the wafer box are spliced ​​to obtain the arc edge morphology; the mobile device changes its position in the z direction after one rotation; the arc edge morphologies of each position of the wafer box in the z direction are spliced ​​to obtain the three-dimensional morphology of the wafer box.

[0062] Specifically, the camera obtains the arc edge points of the wafer in the two-dimensional image. The arc edge points contain information in the x and z directions. The arc edge points at different x positions are obtained by the rotation of the mobile device, and the two-dimensional arc edge points are spliced ​​to obtain the arc edge morphology. Considering the limited width of the light plane, the mobile device needs to change the position in the z direction after one rotation to complete the acquisition of the arc edge morphology of the entire box wafer.

[0063] See also Fig.14 An embodiment of the present invention further provides a device for detecting the placement status of wafers in a wafer box, which implements a method for detecting the placement status of wafers in a wafer box. The detection device includes a laser and a camera; wherein the laser is a line laser and the camera is an area array camera; the line laser is used to emit a laser beam, and the area array camera is used to capture the reflected image after the laser is irradiated to the arc edge of each wafer in the wafer box.

[0064] Specifically, the detection device for the placement status of wafers in a wafer box of the present invention realizes the detection method for the placement status of wafers in a wafer box of any technical solution of the present invention. Therefore, it has all the beneficial effects of the detection method for the placement status of wafers in a wafer box of any technical solution of the present invention, which will not be repeated here.

[0065] Specifically, the present invention can detect wafer boxes containing 150 mm and 200 mm wafers. In this embodiment, the laser and the camera are placed in a metal box with a length and width of 60 mm and a height of 40 mm. In other embodiments, the size of the laser and the camera can be reduced and installed inside a mobile device, which can save space and reduce costs to a certain extent.

[0066] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for detecting the placement status of wafers in a wafer box, applied to the detection of a wafer box, characterized in that: The detection method comprises: Obtain the standard value of thickness and standard value of angle of wafer; Scanning the wafer box using a laser and a camera to obtain a three-dimensional shape of the wafer box; According to the three-dimensional morphology, a thickness calculation algorithm and an angle calculation algorithm are used to calculate the thickness and angle of each wafer in the wafer box; the thickness calculation algorithm processes the data of the three-dimensional morphology through a point cloud downsampling method and a point cloud clustering method, and projects it into a two-dimensional plane, and uses a rotating caliper method in the two-dimensional plane to determine the thickness of each wafer in the wafer box; wherein, the point cloud downsampling method is specifically used to perform a thinning operation on the data of the three-dimensional morphology to reduce the amount of data; the point cloud clustering method is used to separate the arc edge morphologies of different wafers in the three-dimensional morphology to obtain the arc edge morphologies of wafers at different positions; according to the arc edge morphology of each wafer, it is projected on the x, z plane to convert it into a two-dimensional plane dimensional plane, and use the rotating caliper method in the two-dimensional plane to calculate the minimum circumscribed rectangle of each wafer, the short side of the minimum circumscribed rectangle is the thickness of the wafer; the angle calculation algorithm uses the result of the point cloud clustering method of the thickness calculation algorithm to project the three-dimensional point cloud of the arc edge morphology of each wafer on the x, y plane to convert it into a two-dimensional plane; in the two-dimensional plane, for the arc edge morphology of each wafer, extract the points with the maximum y value in the x direction, and these points constitute the top point set; according to the top point set, fit the points in the set by the least squares method to obtain the straight line equation; the angle between the straight line of the straight line equation and the x direction is the angle of the wafer; The thickness and angle of each wafer in the wafer box are compared with the thickness standard value and the angle standard value to determine whether there are duplicate wafers, skewed wafers, and missing wafers in the wafer box.

2. The method for detecting the placement status of wafers in a wafer box according to claim 1, characterized in that: The step of obtaining the thickness standard value and the angle standard value of the wafer includes: Obtain a standard wafer box in which all wafers are normally placed, and use the laser and the camera to scan and establish a three-dimensional topography of the standard wafer box; The thickness calculation algorithm and the angle calculation algorithm are used according to the three-dimensional appearance of the standard wafer box to calculate the thickness standard value and the angle standard value.

3. The method for detecting the placement status of wafers in a wafer box according to claim 1, characterized in that: The method of scanning the wafer box using a laser and a camera includes: The laser emits laser light to the wafer box, and after being reflected by the arc edge of the wafer, the laser light is focused on the imaging plane by the lens of the camera to form a two-dimensional image of the arc edge of the wafer; The light plane formed by the laser emitted by the laser is parallel to the wafer in the wafer box, the focus of the camera is on the light plane, and the imaging plane is perpendicular to the light plane.

4. The method for detecting the placement status of wafers in a wafer box according to claim 3, characterized in that: The laser and the camera are driven by a moving device to move in the z direction and scan the wafer box; The obtaining of the three-dimensional morphology of the wafer box comprises: The camera collects two-dimensional images of the arc edge of the wafer in the wafer box in the x and y directions, and obtains the height of the mobile device in the z direction in real time to obtain three-dimensional information of the wafer at the height; The laser and the camera are driven to move in the z direction by the moving device to obtain three-dimensional information of each wafer in the wafer box; The three-dimensional information of each wafer in the wafer box is spliced ​​to obtain the three-dimensional morphology of the wafer box.

5. The method for detecting the placement status of wafers in a wafer box according to claim 1, characterized in that: The method of scanning the wafer box using a laser and a camera includes: The laser emits laser light to the wafer box, and after being reflected by the arc edge of the wafer, the laser light is focused on the imaging plane by the lens of the camera to form an image of the arc edge of the wafer; The light plane formed by the laser emitted by the laser is perpendicular to the wafers in the wafer box, and the imaging plane is perpendicular to the wafers in the wafer box.

6. The method for detecting the placement status of wafers in a wafer box according to claim 5, characterized in that: The laser and the camera are driven by a moving device to rotate or translate in the z direction to scan the wafer box; The obtaining of the three-dimensional morphology of the wafer box comprises: The camera collects arc edge points of the arc edge of the wafer in the wafer box in the x and z directions; The laser and the camera are driven to rotate by the moving device to obtain arc edge points at different x positions; Splicing the arc edge points of each wafer in the wafer box to obtain an arc edge morphology; The moving device changes the position in the z direction after one rotation is completed; The arc edge morphologies at various positions of the wafer box in the z direction are spliced ​​to obtain a three-dimensional morphology of the wafer box.

7. A device for detecting the placement status of wafers in a wafer box, characterized in that: The detection device for the placement state of wafers in a wafer box implements the detection method for the placement state of wafers in a wafer box as described in any one of claims 1 to 6, and the detection device includes a laser and a camera; Among them, the laser is a line laser, and the camera is an area array camera; the line laser is used to emit a laser beam, and the area array camera is used to capture a reflected image after the laser is irradiated onto the arc edge of each wafer in the wafer box.

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