Methods, systems and computer-readable storage media for detecting arcs

Abstract

This invention provides a method, system, and computer-readable storage medium for detecting arc lines. The detection method includes the following steps: capturing an image of a semiconductor product along a first direction to obtain a first image; capturing an image of the semiconductor product along a second direction (vertically downward) to obtain a second image; the angle between the first and second directions being an image acquisition angle, which is an acute angle; fusing the first and second images to form a fused image; obtaining the distance L1 between a first imaging point and a second imaging point in the fused image; and determining the height of the arc line based on L1 and the image acquisition angle. This invention's detection method can detect the height of arc lines, offering high detection efficiency and low cost. Furthermore, this method is independent of the position of the arc line's shadow, and the positional deviation of the light source has minimal impact on the detection, resulting in high accuracy in detecting the height of the arc line.

Description

Technical Field

[0001] This invention relates to the field of semiconductor testing technology, and in particular to a method, system and computer-readable storage medium for detecting arc lines. Background Technology

[0002] In semiconductor products, electrical connections are established between chips and substrates using bonding wires. Bonding wires typically consist of one or more arcs. The ends of the arcs are soldered to pads or the substrate, while the middle portion of the arc bends upwards relative to the substrate. The height of the arc is one indicator used to assess the quality of a semiconductor product. For example, if the arc height is too low, there is a risk of arc collapse, and the middle portion of the arc may come into contact with the substrate, potentially causing a short circuit in the semiconductor product.

[0003] In existing technologies, the height of a line arc is detected using 3D vision measurement equipment. The method for measuring the height of a line arc using this equipment is roughly as follows: A camera captures an image of the semiconductor product from a top-down angle. When the camera's focal length is at a certain value, some points on the line arc are clearly visible, while others are blurry. The clearly visible points can be considered to be at the camera's focal point. Based on the distance between the camera and the substrate, and the camera's focal length, the height of those clearly visible points relative to the substrate can be calculated. By changing the camera's focal length and capturing multiple images, the height of each point on the line arc relative to the substrate can be obtained, thus determining the height of the highest point of the line arc.

[0004] However, existing line arc height detection methods require the camera to change its focal length multiple times and acquire a large number of images (potentially a dozen or even dozens of images), resulting in a time-consuming and inefficient process. Furthermore, the aforementioned 3D vision measurement equipment is costly. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a method for detecting line arcs, which can detect the height of line arcs, and the detection method has high detection efficiency and low detection cost.

[0006] The present invention also proposes a detection system.

[0007] The present invention also proposes a computer-readable storage medium.

[0008] According to a first aspect of the present invention, a method for detecting the height of a line arc in a semiconductor product is used. The semiconductor product includes a substrate and a bonding wire, the bonding wire includes at least one line arc, the line arc being located above the substrate, and the height of the line arc is defined as the actual distance between a target point of the line arc and the substrate in the vertical direction. The detection method includes the following steps: taking a picture of the semiconductor product along a first direction to obtain a first image; taking a picture of the semiconductor product along a second direction to obtain a second image, the first image including at least first image information of the line arc, the second image including at least second image information of the line arc, the second direction being a vertically downward direction, the first direction being inclined relative to the second direction, defining the angle between the first direction and the second direction as an image acquisition angle, the image acquisition angle being an acute angle; fusing the first image and the second image to form a fused image, the fused image including the first image information and the second image information; determining a first imaging point of the target point within the first image information of the fused image, determining a second imaging point of the target point within the second image information of the fused image, obtaining a distance L1 between the first imaging point and the second imaging point; and determining the height of the line arc based on L1 and the image acquisition angle.

[0009] The detection method according to a first aspect of the present invention has at least the following advantages: The detection method of the present invention can detect the height of a line arc using only two images, requiring fewer images and eliminating the need for multiple focusing adjustments of the camera used for image acquisition. This detection method has a shorter detection time and higher detection efficiency for line arc height. Furthermore, unlike the prior art, the detection method of the present invention does not require the use of existing 3D vision detection equipment or cameras with complex zoom structures, thus reducing the cost of detecting line arc height.

[0010] Furthermore, this method uses image fusion to find the imaging position of a reference line segment (line segment AB0) in the original first image, thereby determining the height of the arc. This detection method does not depend on the position of the shadow formed by the arc on the substrate. Even if the shadow formed by the arc on the substrate is not a direct projection of the arc, it does not affect the detection. The positional deviation of the light source has a low impact on the accuracy of the arc height detection.

[0011] According to some embodiments of the present invention, determining the height of the arc based on L1 and the image acquisition angle includes: calculating the height of the arc according to the following formula: H = L2 / sinα, L2 = L1 / p; where H is the height of the arc, α is the image acquisition angle, and p is the ratio between the size of the semiconductor product in the fused image and the actual size of the semiconductor product.

[0012] According to some embodiments of the present invention, the image acquisition angle is α, where 15° < α < 90°.

[0013] According to some embodiments of the present invention, L2 = L1.

[0014] According to some embodiments of the present invention, the imaging point of the first end of the arc in the first image is a first reference point, the imaging point of the second end of the arc in the first image is a second reference point, the imaging point of the first end of the arc in the second image is a third reference point, and the imaging point of the second end of the arc in the second image is a fourth reference point; in the fused image, the first reference point and the third reference point coincide, and the second reference point and the fourth reference point coincide.

[0015] According to some embodiments of the present invention, the detection method further includes the following steps: determining whether the semiconductor product has at least one of the following appearance defects based on at least one of the first image and the second image: the arc is bent in the horizontal direction, the arc is broken, the endpoint of the arc is abnormally positioned, or there are foreign objects on the surface of the substrate.

[0016] A detection system according to a second aspect of the present invention includes: a detection stage for carrying a semiconductor product, the semiconductor product including a substrate and bonding wires, the bonding wires including at least one arc segment located above the substrate; a first camera with its lens facing the detection stage, the first camera being used to capture an image of the semiconductor product located on the detection stage along a first direction to obtain a first image; and a second camera with its lens facing the detection stage, the image acquisition range of the first camera and the image acquisition range of the second camera at least partially overlapping, the second camera being used to capture an image of the semiconductor product along a second direction to obtain a second image, the angle between the first direction and the second direction being an image acquisition angle, the second direction being a vertical direction. The image acquisition angle is acute. The first image includes at least first image information of the arc, and the second image includes at least second image information of the arc. A processor is used, with both the first and second cameras communicatively connected to it. The processor is configured to: fuse the first image and the second image to form a fused image, the fused image including at least the first image information and the second image information; determine a first imaging point of the target point within the first image information of the fused image, determine a second imaging point of the target point within the second image information of the fused image, and obtain the distance L1 between the first imaging point and the second imaging point; and determine the height of the arc based on L1 and the image acquisition angle.

[0017] The detection system according to a second aspect of the present invention has at least the following advantages: The detection system detects the height of a line arc by processing two images; the system requires fewer images and eliminates the need for multiple refocusing adjustments of the camera used to acquire the images. The system has a shorter detection time and higher detection efficiency for line arc height. Furthermore, compared to existing 3D vision inspection devices, the system has a lower cost.

[0018] According to some embodiments of the present invention, both the first camera and the second camera are located above the detection platform, the detection platform is horizontally arranged, the optical axis of the second camera is perpendicular to the detection platform, and the angle between the optical axis of the first camera and the detection platform is an acute angle.

[0019] According to some embodiments of the present invention, at least one of the position and angle of the first camera relative to the detection stage is adjustable; and / or, at least one of the position and angle of the second camera relative to the detection stage is adjustable.

[0020] According to some embodiments of the present invention, the detection system further includes a light source disposed above the detection stage, and the light emitted by the light source is configured such that the shadow formed by the arc on the substrate is the orthographic projection of the arc on the substrate.

[0021] According to a third aspect of the present invention, a computer-readable storage medium stores computer-executable instructions for causing a computer to perform the detection method as described in the first aspect of the present invention.

[0022] The computer-readable storage medium according to the third aspect embodiment of the present invention has the same beneficial effects as the detection method of the first aspect embodiment, and will not be described again here.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0025] Figure 1 A schematic diagram of a semiconductor product;

[0026] Figure 2 This is a front view of a detection system according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of a right-angled triangle constructed for measuring the height of a line arc in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram illustrating the principle of the detection method in this embodiment of the invention;

[0029] Figure 5 This is a schematic diagram of the first image in one embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the second image in one embodiment of the present invention;

[0031] Figure 7 for Figure 5 Enlarged view of region C in the image;

[0032] Figure 8 for Figure 6 Enlarged view of region D in the image;

[0033] Figure 9 A schematic diagram of a portion of the fused image;

[0034] Figure 10This is a schematic diagram of a detection method according to one embodiment of the present invention;

[0035] Figure 11 This is a schematic diagram of a detection method according to another embodiment of the present invention.

[0036] Figure label:

[0037] 100 - Semiconductor product, 101 - Substrate, 102 - Chip, 103 - Bonding wire, 104 - Target point, 105 - Line arc, 106 - Shading;

[0038] 200-Detection system, 201-First camera, 202-Second camera, 203-Detection platform, 204-Light source, 205-First optical axis, 206-Second optical axis;

[0039] 301 - First reference point, 302 - Second reference point, 303 - Third reference point, 304 - Fourth reference point, 305 - Reference plane, 306 - Window. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0042] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0043] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0044] To facilitate the description of the detection method and detection system 200 of the present invention, the semiconductor product 100 to be detected will be described first. Figure 1 As shown, the semiconductor product 100 includes a substrate 101, a chip 102, and a bonding wire 103. The chip 102 is fixed on the substrate 101, and the bonding wire 103 is located on the top of the substrate 101. Figure 1 In this configuration, the bonding wire 103 includes only one arc 105. One end of the arc 105 is connected to the substrate 101, and the other end is connected to the chip 102. The middle portion of the arc 105 bends upward relative to the substrate 101. Figure 5 As shown, in some other embodiments, a bonding wire 103 may also include multiple wire arcs 105. Furthermore, as... Figure 5 As shown, the arc 105 is not only used to connect the chip 102 and the substrate 101; the two ends of some arcs 105 can also be connected to different parts of the substrate 101 respectively.

[0045] like Figure 1 As shown, in this invention, the height H of the arc 105 is the actual vertical distance between the target point 104 of the arc 105 and the substrate 101. The target point 104 of the arc 105 can be the highest point of the arc 105, or any other point on the arc 105 other than the highest point and the endpoints of the arc 105.

[0046] Figure 2 A detection system 200 according to one embodiment of the present invention is shown. The detection system 200 includes a detection stage 203, a first camera 201, a second camera 202, and a processor. The top surface of the detection stage 203 is used to place the semiconductor product 100 to be detected. The detection stage 203 can be horizontally arranged, that is, the top surface of the detection stage 203 is a horizontal plane. The semiconductor product 100 can be placed flat on the detection stage 203. The first camera 201 and the second camera 202 are both located above the detection stage 203. The angle of the first camera 201 relative to the detection stage 203 is different from the angle of the second camera 202 relative to the detection stage 203. In the present invention, the angle between the camera and the detection stage 203 refers to the angle between the optical axis of the camera and the top surface of the detection stage 203. Specifically, as shown... Figure 2As shown, the optical axis of the first camera 201 is the first optical axis 205, and the optical axis of the second camera 202 is the second optical axis 206. The angle between the first optical axis 205 and the top surface of the detection stage 203 is an acute angle, and the angle between the second optical axis 206 and the top surface of the detection stage 203 is 90°. If the semiconductor product 100 is placed on the detection stage 203, then the angle between the first optical axis 205 and the substrate 101 is an acute angle, and the angle between the second optical axis 206 and the substrate 101 is 90°. The lenses of the first camera 201 and the second camera 202 both face the detection stage 203, and the image detection ranges of the two cameras partially overlap. Both the first camera 201 and the second camera 202 can capture images of the semiconductor product 100 located on the detection stage 203. The image captured by the first camera 201 is the first image, and the image captured by the second camera 202 is the second image. The second image is a top view of the arc 105, and the first image includes the side view of the arc 105. Both the first image and the second image are two-dimensional images.

[0047] The processor is not shown in the accompanying drawings. Both the first camera 201 and the second camera 202 are communicatively connected to the processor, and communication between the cameras and the processor is achieved through wired or wireless connections. The processor can receive images (first images) from the first camera 201 and images (second images) from the second camera 202, and process the images. The processor can be a central processing unit (CPU) or a graphics processing unit (GPU).

[0048] like Figure 2 As shown, the detection system 200 also includes a light source 204, which is located above the detection stage 203. The light emitted by the light source 204 is directed towards the detection stage 203 to improve the brightness and clarity of the first and second images. The light source 204 can be positioned below the first camera 201 and the second camera 202. The light source 204 can have a transparent portion to prevent it from obstructing the field of view of the first camera 201 and the second camera 202. Alternatively, in some embodiments, the light source 204 can be arranged in a ring shape with a clearance hole at its center to prevent it from obstructing the field of view of the first camera 201 and the second camera 202. Or, in other embodiments, the light source 204 can also be offset from the optical axes of the two cameras to prevent it from obstructing the field of view of the first camera 201 and the second camera 202.

[0049] The above-described detection system can detect the height of the arc 105 using the detection method described below. To facilitate the explanation of the function of each step in the detection method below, the detection principle of the detection method of the present invention will be introduced first.

[0050] like Figure 3 As shown, the target point 104 of the arc 105 is point B0, the orthographic projection of the target point 104 onto the substrate 101 is projection point B1, and the line connecting the target point 104 (point B0) and projection point B1 is line segment B0B1. Figure 4 As shown, line segment B0B1 is perpendicular to substrate 101, and the actual length of line segment B0B1 is the height H of arc 105.

[0051] like Figure 4 As shown, to obtain the length of line segment B0B1, we can first construct a right triangle AB0B1. Line segment B0B1 is the hypotenuse of this right triangle. If we know the length of one of the legs of this right triangle and the angle of one of its acute angles, then we can determine the length of line segment B0B1, i.e., determine the height of the arc, using trigonometric functions. Figure 4 As shown, H = L² / sinα. If the values ​​of L² and α can be determined, the value of H can be determined. For example, if AB₀ = 0.285 mm and α = 15°, then H = B₀B₁ = 0.285 / sin15° = 1.1 mm.

[0052] The following explains how a linear triangle AB0B1 is formed. Figure 3 and Figure 4 As shown, a reference plane 305 exists in actual space, satisfying the following conditions: target point B0 lies on reference plane 305, and reference plane 305 is perpendicular to the first optical axis 205. A point A exists on reference plane 305, and the line connecting point A and projection point B1 is perpendicular to reference plane 305. Therefore, line segment AB0 lies on reference plane 305, and line segment AB0 is perpendicular to line segment B0B1. Points A, B0, and B1 are the three endpoints of a right triangle.

[0053] Line segment AB0 corresponds to line segment B2B3 in the fused image, which is the image formed by fusing the first and second images. There is a certain proportional relationship between line segment B2B3 and AB0. Once the length of B2B3 in the fused image is determined, the actual length L2 of line segment AB0 can also be determined. Specifically, the imaging point of target point 104 in the first image is the first imaging point B2, and the imaging point of target point 104 in the second image is the second imaging point B3. The fused image also includes the first imaging point B2 and the second imaging point B3.

[0054] Figure 5 The image shows a first image of a semiconductor product 100 being inspected. Figure 6 A second image of the semiconductor product 100 is shown. Figure 7 It shows Figure 5 The arc of the line in region C is 105. Figure 8 It shows Figure 6 The arc of the line in region D is 105. Figure 7 and Figure 8 The same arc 105 is shown. But Figure 7 and Figure 8 The state of the arc 105 is shown from different viewpoints. The state of the arc 105 in the first image is different from that in the second image, and the position of the target point 104 relative to the endpoint of the arc 105 is different in the first and second images. Specifically, as shown... Figure 7 As shown, the first endpoint of the arc 105 is imaged at the first reference point 301 in the first image, and the second endpoint of the arc 105 is imaged at the second reference point 302 in the first image. The line connecting the first reference point 301 and the second reference point 302 ( Figure 7 The dashed line segment in the image is spaced apart from the first imaging point B2. For example... Figure 8 As shown, the first endpoint of line arc 105 is imaged at the third reference point 303 in the second image, and the second endpoint of line arc 105 is imaged at the fourth reference point 304 in the second image. In the second image, the first reference point 301, the second reference point 302, and the first image point B2 are collinear. Figure 5 The first image shown and Figure 6 The second image shown can be fused to obtain a fused image. Figure 9 It is part of the fused image. Figure 9 That is to say Figure 7 and Figure 8 The image obtained after fusion.

[0055] The following explains why line segment AB0 corresponds to line segment B2B3 in the fused image.

[0056] Since the reference plane 305 is perpendicular to the first optical axis 205, and parallel to the imaging plane of the first camera 201 (not shown), the imaging plane of the first camera 201 is located on the imaging element of the first camera 201 and is perpendicular to the first optical axis 205. Because the reference plane 305 is parallel to the imaging plane of the first camera 201, based on the principle of planar imaging, the image of line segment AB0 on ​​the imaging plane of the first camera 201 is parallel to the actual line segment AB0, and the two are proportionally related. Therefore, assuming that the imaging position of line segment AB0 in the first image can be directly determined from the first image, the actual length L2 of line segment AB0 can be determined.

[0057] However, point A is a point on a virtual plane, and relying solely on the first image, its position within the first image may be difficult to determine directly. Although points A and B1 coincide in the first image, if the shadow 106 formed by the arc 105 on the substrate is not a projection of the arc 105, the processor cannot find the imaging point of projection point B1 in the shadow image. Therefore, when the shadow formed by the arc 105 on the substrate 101 is not a projection of the arc 105, it may also be difficult to determine the position of point A using the position of projection point B1.

[0058] Therefore, this invention uses image fusion to determine the theoretical position of point A in the first image.

[0059] Please refer to Figure 4 Imagine the following scenario: Using point B1 as the center, rotate the semiconductor product clockwise by an angle α, so that the first optical axis 205 of the first camera 201 is perpendicular to the substrate; while the position of point A remains unchanged. After the semiconductor product rotates, the position of the original target point 104 (B0) will change, and the new position of target point 104 is as follows: Figure 4 As shown at point B4, B0B1 = B1B4. After the semiconductor product rotates, the first camera 201 captures another image. This new image is called the "new first image," and it is essentially identical to the current second image. Figure 6 As shown.

[0060] Therefore, the original first image (such as Figure 7 The first image (as shown) is fused with the second image, which is equivalent to fusion of the original first image with the new first image. Since both the original first image and the new first image are acquired based on the first camera 201, the image perspective of the fused image can be considered to be the same as that of the original first image.

[0061] like Figure 4 As shown, points B4, A, and B1 are all located on the first optical axis 205. Therefore, after the semiconductor product is rotated, points B4, A, and B1 coincide in the new first image. By determining the position of point B4 in the new first image, the position of point A in the original first image can be determined. Correspondingly, the imaging position of line segment AB0 in the original first image is equivalent to that of line segment B2B4 in the fused image (e.g., ...). Figure 9 (As shown). Based on the above description, since the new first image is the same as the current second image, point B4 in the new first image is point B3 in the second image. Therefore, line segment B2B3 in the fused image is the image of line segment AB0 in the original first image.

[0062] As mentioned above, the image perspective of the fused image can be considered the same as that of the original first image, and the imaging plane of the first camera is parallel to the reference plane 305. Therefore, based on the imaging principle, line segment B2B3 is parallel to AB0, and the two have a certain proportional relationship. This proportional relationship depends on the distance between line segment AB0 and the first camera 201 and the focal length of the first camera 201. After the length of B2B3 in the fused image is determined, the actual length L2 of line segment AB0 can also be determined.

[0063] The above section explained how to determine L2, while the method for determining α is relatively simple. For example... Figure 4 As shown, the first optical axis 205 intersects with the second optical axis 206, and the angle between the first optical axis 205 and the second optical axis 206 is the image acquisition angle, which is α. After the first camera 201 and the second camera 202 are debugged, α can be determined by measuring the angle between the first optical axis 205 and the second optical axis 206. It should be noted that... Figure 4 In the first optical axis 205, the second optical axis 206 passes through the target point B0, and the intersection of the first optical axis 205 and the reference plane 305 is point A. However, in some other embodiments, point A does not necessarily need to be located on the first optical axis 205, as long as the measured arc 105 is within the image acquisition range of the first camera 201.

[0064] In summary, based on the above principles, such as Figure 10 The detection method of the present invention shown includes the following steps:

[0065] S11: Take a picture of the semiconductor product 100 along the first direction to obtain a first image, and take a picture of the semiconductor product 100 along the second direction to obtain a second image. The first image includes at least the first image information of the line arc 105, and the second image includes at least the second image information of the line arc 105. The second direction is a vertically downward direction, and the first direction is tilted relative to the second direction. The angle between the first direction and the second direction is the image acquisition angle α, and the image acquisition angle is an acute angle.

[0066] S12: The first image and the second image are merged to form a merged image, which includes information from the first image and information from the second image;

[0067] S13: Determine the first imaging point B2 of the target point within the first image information of the fused image, determine the second imaging point B3 of the target point within the second image information of the fused image, and obtain the distance L1 between the first imaging point B2 and the second imaging point B3.

[0068] S14: Determine the height H of the arc based on L1 and the image acquisition angle α.

[0069] The first image is formed by capturing an image with the first camera 201, and the second image is formed by capturing an image with the second camera 202. In step S11, the first image information of the arc 105 is the image of the arc 105 in the first image, and the second image information of the arc 105 is the image of the arc 105 in the second image. Image fusion and finding specific points on the images can be performed by the processor. Figure 8 As shown, during image processing, the processor can create a window 306 at a preset position on the image, that is, select a certain area in the image with a small box. The processor can find the target point 104 of the required arc 105 within the window 306, thereby determining the position of the second imaging point B3. The method for determining the position of the first imaging point B2 is similar; the way the processor finds the endpoints of the arc 105 in the image is similar to the way the processor finds the target point 104 of the arc 105 in the image.

[0070] The detection method of this invention can detect the height of the arc 105 using only two images. This method requires fewer images and eliminates the need for multiple refocusing adjustments of the camera used for image acquisition. The detection method is time-efficient and highly effective in detecting the height of the arc 105. Furthermore, unlike existing technologies, this method does not require the use of conventional 3D vision inspection equipment, thus reducing the cost of detecting the height of the arc 105.

[0071] Furthermore, this method uses image fusion to find the imaging position of a reference line segment (line segment AB0) in the original first image, thereby determining the height of the arc 105. This detection method does not depend on the position of the shadow 106 formed by the arc 105 on the substrate 101. Even if the shadow 106 formed by the arc 105 on the substrate 101 is not a direct projection of the arc 105, it does not affect the detection. The positional deviation of the light source 204 has a low impact on the accuracy of the arc 105 height detection.

[0072] like Figure 9As shown, in some embodiments, the fused image obtained through step S12 satisfies the following conditions: in the fused image, the first reference point 301 and the third reference point 303 coincide, and the second reference point 302 and the fourth reference point 304 coincide. Specifically, the first endpoint of the arc 105 is imaged as the first reference point 301 in the first image, the second endpoint of the arc 105 is imaged as the second reference point 302 in the first image, the first end of the arc 105 is imaged as the third reference point 303 in the second image, and the second end of the arc 105 is imaged as the fourth reference point 304 in the second image. This arrangement facilitates the precise fusion of the first and second images, improving the matching degree between line segment B2B3 in the fused image and line segment AB0 in actual space, thereby improving the measurement accuracy of the height of the arc 105.

[0073] For step S13, the length L1 of line segment B2B3 in the fused image can be determined in the following way: the processor first calculates the number of pixels occupied by line segment B2B3 in the length direction of the line segment in the fused image, and then multiplies the number by the size corresponding to each pixel, so that the length of line segment B2B3 in the fused image can be obtained.

[0074] The length of line segment B2B3 in the fused image is proportional to the length of line segment AB0 in the actual space. For example, if the size of the semiconductor product 100 measured in the fused image is p times the actual size of the semiconductor product 100, then AB0 = B2B3 / p, i.e., L2 = L1 / p; if the size of the object measured in the image is the same as the actual size of the object, then p = 1, L2 = L1. After L2 is determined, in step S14, the processor can calculate the height of the arc 105 according to the formula H = L2 / sinα. After the semiconductor product 100 is placed on the detection stage 203, the distance between the semiconductor product 100 and the two cameras is fixed and measurable, and the focal length of the cameras is also determined. Therefore, the ratio between the size of the semiconductor product 100 in the image and the actual size of the semiconductor product 100 can be determined during the debugging process of the detection system 200.

[0075] In some embodiments, the image acquisition angle α satisfies: 15° < α < 90°. For example, α can be set to 15°, 20°, 30°, 45°, 60°, 75°, 85°, etc. α is less than 90° to construct a right-angled triangle AB0B1. The larger α is, the greater the distance (i.e., L1) between the first imaging point B2 and the second imaging point B3 in the fused image. Setting α greater than 15° helps to increase the value of L1 in the fused image, reduce the relative error of L1, and thus improve the detection accuracy of the height of the arc 105.

[0076] In some embodiments not illustrated, at least one of the position and angle of the first camera 201 relative to the detection stage 203 is adjustable. The user can adjust the position and angle of the first camera 201 to enable it to acquire a suitable image. For example, the detection system 200 may include a support and a movable base, the support being fixed relative to the detection stage 203 and disposed on the side of the detection stage 203, the first camera 201 being fixed to the movable base, and the movable base being movable relative to the support, thereby changing the position of the first camera 201 relative to the detection stage 203. Alternatively, the detection system 200 may include a support and a rotating base, the first camera 201 being fixed to the rotating base, and the rotating base being rotatable relative to the support, thereby changing the angle of the first camera 201 relative to the detection stage 203. If both the position and angle of the first camera 201 need to be adjustable, the detection system 200 may be configured such that the rotating base is mounted on the movable base, the movable base is mounted on the support, and the first camera 201 is fixedly connected to the rotating base.

[0077] Similarly, in some embodiments not illustrated, at least one of the position and angle of the second camera 202 relative to the detection stage 203 is adjustable. The user can adjust the position and angle of the second camera 202 to enable it to acquire suitable images. How the position and angle of the second camera 202 are adjusted can be referred to the above description of the first camera 201, and will not be repeated here.

[0078] like Figure 11 As shown, in another embodiment, the detection method further includes step S15: determining whether the semiconductor product 100 has other appearance defects besides the unacceptable height of the arc 105, based on at least one of the first image and the second image. Besides the unacceptable height of the arc 105, appearance defects of the semiconductor product 100 include: the arc 105 being bent in the horizontal direction, the arc 105 being broken, the endpoints of the arc 105 being abnormally positioned, foreign matter being present on the surface of the substrate 101, etc. Step S13 is also executed by a processor. For example, the processor can detect the edge of the arc 105 to determine the shape of the arc 105, and then determine whether the arc 105 has defects such as breakage or bending. The processor can detect the positions of the pads originally soldered to the arc 105 and the endpoints of the arc 105 to determine whether the endpoint positions of the arc 105 are abnormal. The detection method of this embodiment can detect both the height of the arc 105 and whether there are appearance defects in the arc 105. Using this detection method, the semiconductor product 100 can be inspected from multiple perspectives to evaluate its quality.

[0079] It should be noted that in this invention, the use of designations such as S11, S12, S13, S14, and S15 is mainly for the convenience of describing each step; the numerical value of these designations does not strictly limit the order of these steps. Figure 11 In the illustrated embodiment, steps S12 and S15 are performed simultaneously; however, in other embodiments, step S15 may be performed before step S12 or after step S14.

[0080] Furthermore, in some embodiments, when the second image is a top view of the semiconductor product 100, step S15 can be set to: determine whether the semiconductor product 100 has any appearance defects other than the unacceptable height of the arc 105, based on the second image. Since the second image is a top view of the semiconductor product 100, the overall appearance of the semiconductor product 100 can be seen more clearly from the second image compared to the first image. The arc 105 in the second image obscures other parts of the semiconductor product 100 less, making the second image more suitable for judging the appearance quality of the semiconductor product 100.

[0081] In some embodiments, the light emitted by the light source 204 can be configured such that the shadow 106 formed by the arc 105 on the substrate 101 is the orthographic projection of the arc 105 onto the substrate 101. For example, the light source 204 is located directly above the detection stage 203, and the light emitted by the light source 204 is vertically downward. Figure 5 As shown, the shadow 106 of arc 105 appears in the first image. Since the shadow 106 of arc 105 is the orthographic projection of arc 105, it appears in the second image (e.g.) Figure 6 As shown, the arc 105 basically obscures the shadow 106 of the arc 105, and the shadow 106 basically does not appear in the second image. The shadow 106 of the arc 105 has little interference with the detection of appearance defects, and the detection system 200 has high accuracy in detecting appearance defects of the arc 105.

[0082] In some embodiments not illustrated, the detection system 200 may further include a display screen, which is communicatively connected to the processor. The display screen can show the detection results of the semiconductor product 100, such as the height of the arc 105, whether the arc 105 has any appearance defects, etc. Furthermore, the display screen can also be used to display a first image and a second image, so that the user can identify the defective parts of the semiconductor product 100.

[0083] The present invention also provides a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the detection method as described in any of the above embodiments. Those skilled in the art will understand that computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible by a computer.

[0084] Experiments have shown that, in terms of detecting the height of line arcs 105, the detection method of the present invention can detect 39,900 line arcs 105 per hour, while the detection speed of existing 3D vision inspection equipment can reach 24,000 line arcs 105. The detection speed of the detection method of the present invention is improved by 70% compared with the prior art.

[0085] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A method for detecting linear arcs, characterized in that, The height of the arc in a semiconductor product is used to detect the height of the arc in the semiconductor product, which includes a substrate and a bonding wire. The bonding wire includes at least one arc, which is located above the substrate. The height of the arc is defined as the actual distance between the target point of the arc and the substrate in the vertical direction. The detection method includes the following steps: A first image is obtained by taking a picture of the semiconductor product along a first direction, and a second image is obtained by taking a picture of the semiconductor product along a second direction. The first image includes at least the first image information of the line arc, and the second image includes at least the second image information of the line arc. The second direction is a vertically downward direction, and the first direction is inclined relative to the second direction. The angle between the first direction and the second direction is defined as the image acquisition angle, and the image acquisition angle is an acute angle. The first image and the second image are merged to form a merged image, the merged image including the information of the first image and the information of the second image; A first imaging point of the target point is determined within the first image information of the fused image, and a second imaging point of the target point is determined within the second image information of the fused image. The distance L1 between the first imaging point and the second imaging point is obtained. The height of the arc is determined based on L1 and the included angle of the image acquisition.

2. The detection method according to claim 1, characterized in that, Determining the height of the arc based on L1 and the image acquisition angle includes: The height of the arc is calculated using the following formulas: H = L2 / sinα, L2 = L1 / p; Wherein, H is the height of the arc, α is the image acquisition angle, and p is the ratio between the size of the semiconductor product in the fused image and the actual size of the semiconductor product.

3. The detection method according to claim 1 or 2, characterized in that, The image acquisition angle is α, where 15° < α < 90°.

4. The detection method according to claim 2, characterized in that, L2 = L1.

5. The detection method according to claim 1, characterized in that, The first end of the arc is imaged at a first reference point in the first image, the second end of the arc is imaged at a second reference point in the first image, the first end of the arc is imaged at a third reference point in the second image, and the second end of the arc is imaged at a fourth reference point in the second image. In the fused image, the first reference point and the third reference point coincide, and the second reference point and the fourth reference point coincide.

6. The detection method according to claim 1, characterized in that, The detection method further includes the following steps: Based on at least one of the first image and the second image, determine whether the semiconductor product has at least one of the following appearance defects: the arc is bent in the horizontal direction, the arc is broken, the endpoint of the arc is abnormally positioned, or there is foreign matter on the surface of the substrate.

7. A detection system, characterized in that, The detection system includes: A testing station for holding semiconductor products, the semiconductor products including a substrate and bonding wires, the bonding wires including at least one arc segment located above the substrate; A first camera, the lens of which is directed toward the inspection station, is used to capture a first image of the semiconductor product located on the inspection station along a first direction. The second camera has its lens facing the detection station. The image acquisition range of the first camera and the image acquisition range of the second camera at least partially overlap. The second camera is used to capture the semiconductor product along a second direction to obtain a second image. The angle between the first direction and the second direction is the image acquisition angle. The second direction is a vertical direction. The image acquisition angle is an acute angle. The first image includes at least the first image information of the arc. The second image includes at least the second image information of the arc. The processor is communicatively connected to both the first camera and the second camera. The processor is configured to: fuse the first image and the second image to form a fused image, the fused image including at least the first image information and the second image information; determine a first imaging point of the target point of the arc within the first image information of the fused image, determine a second imaging point of the target point within the second image information of the fused image, obtain the distance L1 between the first imaging point and the second imaging point; and determine the height of the arc based on L1 and the image acquisition angle.

8. The detection system according to claim 7, characterized in that, At least one of the position and angle of the first camera relative to the detection stage is adjustable; And / or, at least one of the position and angle of the second camera relative to the detection stage is adjustable.

9. The detection system according to claim 7, characterized in that, The detection system also includes a light source, which is positioned above the detection stage. The light emitted by the light source is configured such that the shadow cast by the arc on the substrate is the orthographic projection of the arc on the substrate.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the detection method as described in any one of claims 1 to 6.

Images