Dimension measurement equipment of wafer carrier and calculation method thereof

Abstract

The invention discloses dimension measurement equipment of a wafer carrier and a calculation method thereof. The dimension measurement equipment is used for detecting and calculating the appearance dimension of the wafer carrier and detecting and calculating the groove height dimension of the wafer carrier. The size measurement equipment of the wafer carrier comprises a rack, at least two two-axis moving assemblies oppositely arranged on the rack, a lifting rotating assembly arranged between the two two-axis moving assemblies, and at least two detection assemblies arranged at the output ends of the two two-axis moving assemblies respectively. The lifting rotating assembly comprises a fixing block fixedly arranged on the rack, a Z-axis lead screw connected to the fixing block in a screwed mode, a Z-axis motor, a support table, a rotating motor and a carrying table. Compared with the first limiting block, the second limiting block can limit the wafer carriers with larger specifications, so that the measuring equipment can detect the wafer carriers with two different specifications, and the applicability of the measuring equipment is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a wafer carrier size measuring device and a calculation method thereof. Background Art

[0002] The size detection of wafer carrier is an important part of the semiconductor manufacturing process. The main purpose is to ensure that the size of the wafer carrier meets the design requirements to ensure the stability and accuracy of the wafer during the processing. Therefore, the detection device of the wafer carrier is particularly important. For example, Chinese patent CN201020146994.5 discloses a wafer fixing frame detection device, which mainly comprises a turntable driven by a driving component on a detection base, a laser emitter on a first positioning frame of the base, and an image capturer on a second positioning frame. The laser emitter and the image capturer have an angle relative to the turntable, and a computer with image analysis and judgment function is provided. Therefore, when the wafer fixing frame is placed on the turntable and driven to rotate one circle, the laser emitter projects laser light at every angle on the rotating wafer fixing frame, and the image capturer captures images of each laser projection. Then, the computer quickly and accurately judges whether the shape specifications such as the appearance size, thickness and plane of the wafer fixing frame meet the requirements based on the positioning signal of the driving component and the image data captured by the image capturer. However, this device requires the laser transmitter to project laser light onto the rotating wafer fixing frame at every angle, resulting in low detection efficiency. Summary of the invention

[0003] In view of this, the present invention provides a wafer carrier dimension measurement device and a calculation method thereof to solve the above-mentioned problem.

[0004] A wafer carrier dimension measurement device is used to detect and calculate the appearance dimension and the slot height dimension of a wafer carrier. The wafer carrier includes a carrier frame, and two tail plates are arranged in parallel on one side of the carrier frame. The wafer carrier dimension measurement device includes a frame, at least two two-axis moving components relatively arranged on the frame, a lifting and rotating component arranged between the two two-axis moving components, and at least two detection components respectively arranged at the output ends of the two two-axis moving components. The lifting and rotating component includes a fixed block fixedly arranged on the frame, a Z-axis screw screwed on the fixed block, a Z-axis motor arranged at one end of the Z-axis screw, a support table fixedly arranged on the Z-axis motor, a rotating motor arranged on the support table, and a carrier arranged at the output end of the rotating motor. Two first limit blocks are arranged on the carrier, and the first limit blocks are arranged in an L shape, and the openings of the two first limit blocks are arranged back to back. Two second limit blocks are arranged on one side of the two first limit blocks, and the structure of the second limit blocks is the same as that of the first limit blocks. The openings of the two second limit blocks are arranged back to back, and the distance between the two second limit blocks is greater than the distance between the two first limit blocks.

[0005] The calculation method of the wafer carrier size measurement device comprises the following steps: (1) Acquire an image; (2) Obtain the ROI area and its location information in the image to improve the efficiency of image processing; (3) Perform edge analysis on the ROI area. First, perform image denoising and smoothing, then perform threshold segmentation. After the image is binarized, edge line detection is performed on the processed image, and the position information of the edge points in the ROI area is maintained. (4) The position coordinate information of the ROI area and the position coordinate information of the edge line are combined to calculate the actual pixel point information of the edge line in the ROI area; (5) Calculate the pixel information of the edge line in the coordinate system with the center of the image as the coordinate system, and combine it with the position information of the axis to establish a reference system with the reference system of all edge lines as the axis; (6) The distance of the product is obtained by calculating the relative difference in the position information of the edge axis reference system on both sides of the product.

[0006] Furthermore, the two-axis moving assembly includes an X-axis motor arranged on the frame, an X-axis screw rod arranged at the output end of the X-axis click, a first support plate screwed on the X-axis screw rod, a Y-axis motor arranged on the first support plate, a Y-axis screw rod arranged at the output end of the Y-axis motor, and a second support plate screwed on the Y-axis screw rod.

[0007] Furthermore, the length direction of the X-axis lead screw is perpendicular to the length direction of the Y-axis lead screw.

[0008] Furthermore, one end of the Z-axis screw rod away from the Z-axis motor is rotatably connected to the support platform.

[0009] Furthermore, the length direction of the Z-axis screw rod is perpendicular to the horizontal plane, and is perpendicular to the length direction of the X-axis screw rod and the length direction of the Y-axis screw rod.

[0010] Furthermore, the detection component includes a visual detector and at least four fill lights respectively arranged on two sides of the visual detector.

[0011] Furthermore, the output directions of the two visual detectors are arranged opposite to each other and are both directed toward the carrier.

[0012] Furthermore, the two fill-in lights on the same side of the visual detector are arranged outwardly, and the angle between the lamp surfaces of the two fill-in lights is greater than 180 degrees.

[0013] Compared with the prior art, the wafer carrier size measurement device and calculation method provided by the present invention drives the detection component to move in a two-dimensional plane through the two-axis moving component, and the lifting and rotating component drives and drives the wafer carrier placed on the carrier to lift and rotate, so that the two detection components can simultaneously perform all-round size detection on the wafer carrier to improve the detection accuracy and detection efficiency. In addition, compared with the first limit block, the second limit block can limit the larger wafer carrier, so that the measurement device can detect two wafer carriers of different specifications, thereby improving the applicability of the measurement device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic structural diagram of a wafer carrier dimension measuring device provided by the present invention.

[0015] Figure 2 A schematic diagram of the steps of the wafer carrier size measurement device and the calculation method provided by the present invention.

[0016] Figure 3 for Figure 1A schematic structural diagram of a wafer carrier included in a wafer carrier size measuring device.

[0017] Figure 4 for Figure 1 A schematic structural diagram of a two-axis moving component and a detection component of a wafer carrier dimension measuring device.

[0018] Figure 5 for Figure 1 A schematic structural diagram of a lifting and rotating assembly of a wafer carrier dimension measuring device.

[0019] Explanation of the accompanying figures: frame 10, two-axis moving assembly 20, X-axis motor 21, X-axis screw 22, first support plate 23, Y-axis motor 24, Y-axis screw 25, second support plate 26, lifting and rotating assembly 30, fixed block 31, Z-axis screw 32, Z-axis motor 33, support table 34, rotating motor 35, carrier 36, first limit block 37, second limit block 38, detection assembly 40, visual inspection instrument 41, fill light 42, wafer carrier 50, carrier frame 51, blocking column 52, slot 53, tail plate 54. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention are further described in detail below. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the protection scope of the present invention.

[0021] like Figure 1 As shown, it is a schematic diagram of the structure of the wafer carrier size measurement device provided by the present invention. The wafer carrier size measurement device includes a frame 10, at least two two-axis moving components 20 relatively arranged on the frame 10, a lifting and rotating component 30 arranged between the two two-axis moving components 20, and at least two detection components 40 respectively arranged at the output ends of the two two-axis moving components 20. It can be imagined that the wafer carrier size measurement device and its calculation method also include some other functional modules, such as a power supply module, a gas supply module, etc., which are technologies already known to those skilled in the art and will not be described one by one here.

[0022] The wafer carrier size measuring device and calculation method are used to detect the appearance size and slot height size of a wafer carrier 50. The wafer carrier 50 includes a carrier frame 51, at least four stopper posts 52 arranged on both sides of the carrier frame 51, and a plurality of card slots 53 opened on both sides of the carrier frame 51. The plurality of card slots 53 are used to place wafers, and are clamped by the stopper posts 52, so that the wafer carrier 50 can load multiple wafers. Two tail plates 54 are arranged in parallel on one side of the carrier frame 51, and the two tail plates 54 can cooperate with the lifting and rotating assembly 30 to limit the wafer carrier 50, so as to stabilize the wafer carrier 50 during the lifting and rotating operation. The specific cooperation between the tail plate 54 and the lifting and rotating assembly 30 will be described below.

[0023] The frame 10 is used to carry the above-mentioned components so that they can complete various coordinations, thereby performing size detection on the wafer carrier 50 .

[0024] The two-axis moving assembly 20 includes an X-axis motor 21 arranged on the frame 10, an X-axis screw rod 22 arranged at the output end of the X-axis motor 21, a first support plate 23 screwed on the X-axis screw rod 22, a Y-axis motor 24 arranged on the first support plate 23, a Y-axis screw rod 25 arranged at the output end of the Y-axis motor 24, and a second support plate 26 screwed on the Y-axis screw rod 25.

[0025] The X-axis motor 21 can drive the X-axis screw 22 to rotate, and the Y-axis motor 24 can drive the Y-axis screw 25 to rotate, thereby driving the first support plate 23 and the second support plate 26 screwed to the X-axis motor 21 and the Y-axis screw 25 to move. The length direction of the X-axis screw 22 is perpendicular to the length direction of the Y-axis screw 25, and the detection component 40 is arranged on the second support plate 26, so that the driving of the X-axis motor 21 and the Y-axis motor 24 can drive the detection component 40 to move in a two-dimensional plane, so that the distance and orientation between the two detection components 40 and the wafer carrier 50 can be controlled.

[0026] The lifting and rotating assembly 30 includes a fixed block 31 fixedly arranged on the frame 10, a Z-axis screw rod 32 screwed on the fixed block 31, a Z-axis motor 33 arranged at one end of the Z-axis screw rod 32, a support platform 34 fixedly arranged on the Z-axis motor 33, a rotating motor 35 arranged on the support platform 34, and a carrier 36 arranged at the output end of the rotating motor 35.

[0027] One end of the Z-axis screw rod 32 away from the Z-axis motor 33 is rotatably connected to the support platform 34, and the Z-axis motor 33 can drive the Z-axis screw rod 32 to rotate, thereby driving the support platform 34 to move. The length direction of the Z-axis screw rod 32 is perpendicular to the horizontal plane, and is perpendicular to the length directions of the X-axis screw rod 22 and the Y-axis screw rod 25, so that the moving direction of the support platform 34 is perpendicular to the moving plane of the two-axis moving assembly 20.

[0028] The rotating motor 35 can drive the carrier 36 to rotate, thereby driving the wafer carrier 50 placed on the carrier 36 to rotate. When the wafer carrier 50 placed on the carrier 36 rotates to open toward one of the detection components 40, the detection component 40 can perform dimensional detection on the inside of the wafer carrier 50 to measure the slot height, slot width, etc. of the slot 53.

[0029] Two first limit blocks 37 are disposed on the carrier 36. The first limit blocks 37 are L-shaped, and the openings of the two first limit blocks 37 are disposed opposite to each other, so that the two tail plates 54 on the wafer carrier 50 can be stuck in the two first limit blocks 37, thereby completing the limit function of the wafer carrier 50, so as to stabilize the wafer carrier 50 in the subsequent lifting and rotating operations.

[0030] Two second limit blocks 38 are arranged on one side of the two first limit blocks 37. The structure of the second limit blocks 38 is the same as that of the first limit blocks 37. The openings of the two second limit blocks 38 are arranged back to back, and the distance between the two second limit blocks 38 is greater than the distance between the two first limit blocks 37. In this way, the two second limit blocks 38 can limit the larger wafer carrier 50, so that the measuring equipment can detect the two wafer carriers with different specifications, thereby improving the applicability of the measuring equipment.

[0031] The detection assembly 40 includes a visual detector 41 disposed on the second support plate 26 , and at least four fill lights 42 respectively disposed on two sides of the visual detector 41 .

[0032] The visual inspection instrument 41 is a device that uses machine vision technology to inspect objects. It captures the image of the object through an image capture device (such as a CMOS and CCD camera) and transmits these image signals to a dedicated image processing system. The image processing system performs various operations on these signals, extracts the characteristics of the target, and displays the data.

[0033] The output directions of the two visual inspection instruments 41 are arranged opposite to each other and both face the carrier 36 , so that the two visual inspection instruments 41 can cooperate with the two-axis moving component 20 and the lifting and rotating component 30 to measure the wafer carrier placed on the carrier 36 .

[0034] The two fill lights 42 on the same side of the visual inspection instrument 41 are arranged to expand outward, that is, the angle between the lamp surfaces of the two fill lights 42 is greater than 180 degrees, so that the irradiated light can be diffused to fully illuminate the wafer carrier 50, thereby compensating for insufficient lighting during the inspection operation and improving the inspection quality of the visual inspection instrument 41.

[0035] The two relatively arranged detection components 40 can simultaneously perform front-to-back detection on the wafer carrier 50. In this way, the lifting and rotating component 30 only needs to rotate the wafer carrier 50 180 degrees to complete the full-size detection of the wafer carrier 50, thereby improving the detection efficiency of the measuring equipment.

[0036] The steps of the calculation method of the wafer carrier size measurement device are as follows:

[0037] (1) Obtain an image.

[0038] The image of the wafer carrier 50 is captured by the visual inspection instrument 41 and uploaded to a computer.

[0039] (2) Obtain the ROI area and its location information in the image to improve the efficiency of image processing.

[0040] After image processing, areas that require special attention are outlined from the image. These areas can be marked by boxes, circles, ellipses or irregular polygons, and the marked areas are the ROI areas.

[0041] (3) Perform edge analysis on the ROI area. First, perform image denoising and smoothing, then perform threshold segmentation. After the image is binarized, edge line detection is performed on the processed image, and the position information of the edge points in the ROI area is maintained.

[0042] First, use a filter to remove noise and smooth the image.

[0043] Then, according to the product characteristics and measurement environment (using backlight), a fixed grayscale threshold parameter is set. If the grayscale value on the image is higher than the threshold parameter, the point is white, and if the grayscale value on the image is lower than the threshold parameter, the point is black, so as to eliminate false edges and separate the object from the background for user observation.

[0044] The gradient of the image in the X and Y directions is calculated according to the Sobel operator, and then the gradient amplitude is calculated. Two thresholds are obtained by the accuracy requirement. If the gradient amplitude is greater than the high threshold, the pixel is marked as a "strong edge". If the gradient amplitude is between the low threshold and the high threshold, the pixel may be an edge, but it needs to be connected to a strong edge to be retained. If the gradient amplitude is less than the low threshold, the pixel is ignored. Since the calculation method is used to detect the slot width of the slot 53 on the wafer carrier 50, the edge point information of the slot 53 is difficult to be an idealized straight line, and the approximate straight lines of the two edges of the slot 53 are not necessarily parallel. Therefore, the error will be large when the size is calculated by the point-to-point distance. The characteristics of the particle concave and convex of the edge point can be neutralized by fitting the straight line, so that the calculation result is more reasonable. The method of fitting the straight line is: extracting the straight line from the edge image using the Hough transform, by converting the pixel points from the image space to the parameter control, finding the accumulated value with the most points in the polar coordinate space, determining an execution, and then converting the result of the polar coordinate space back to the image space to draw the detected straight line.

[0045] While obtaining the position information of the edge line, the position information of the edge point in the ROI area is maintained.

[0046] (4) The position coordinate information of the ROI area and the position coordinate information of the edge line are combined to calculate the actual pixel point information of the edge line in the ROI area.

[0047] The position coordinate information of the ROI area and the position coordinate information of the edge point obtained in the second step are calculated by identifying in pixel mode, with pixel (px) as the unit. Therefore, it is necessary to convert the position coordinate information of the ROI area and the position coordinate information of the edge point, and use the internal parameters of the camera (known information) to obtain the actual position information of the edge point in the ROI area, in units (um or mm, etc.).

[0048] (5) Calculate the pixel information of the edge line in the coordinate system with the center of the image as the coordinate system, and combine it with the position information of the axis to establish a reference system with the reference system of all edge lines as the axis.

[0049] The first reference system is established with the center of the image as the coordinate system, and the position coordinates of the edge line in the image are obtained by calculation, that is, the distance d between the edge line and the Y axis in the coordinate system. Then, the second reference system is established with an origin on the axis as the coordinate system, and the position information of the image center is obtained, that is, the distance D between the image center and the Y axis in the coordinate system.

[0050] (6) The distance of the product is obtained by calculating the relative difference in the position information of the edge axis reference system on both sides of the product.

[0051] Select the position information of two edge lines in the first reference system and the second reference system respectively, and obtain edge line 1: (d1, D1), edge line 2 (d2, D2), so that the distance between the two edge lines is: (d1+D1)-(d2+D2).

[0052] Compared with the prior art, the wafer carrier size measurement device and calculation method provided by the present invention drives the detection component 40 to move in a two-dimensional plane through the two-axis moving component 20, and the lifting and rotating component 30 drives and drives the wafer carrier 50 placed on the carrier 36 to lift and rotate, so that the two detection components 40 can simultaneously perform all-round size detection on the wafer carrier 50 to improve the detection accuracy and detection efficiency. In addition, compared with the first limit block 37, the second limit block 38 can limit the larger wafer carrier 50, so that the measurement device can detect two wafer carriers of different specifications, thereby improving the applicability of the measurement device.

[0053] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modification, equivalent substitution or improvement within the spirit of the present invention is included in the scope of the claims of the present invention.

Claims

1. A wafer carrier dimension measurement device, which is used to detect and calculate the appearance dimension and slot height dimension of a wafer carrier, the wafer carrier includes a carrier frame, and two tail plates are arranged in parallel on one side of the carrier frame. The wafer carrier dimension measurement device is characterized in that: the wafer carrier dimension measurement device includes a frame, at least two two-axis moving components relatively arranged on the frame, a lifting and rotating component arranged between the two two-axis moving components, and at least two detection components respectively arranged at the output ends of the two two-axis moving components, the lifting and rotating component includes a fixed block fixedly arranged on the frame, a screw-connected fixed block and a screw-connected fixed block. A Z-axis screw on the fixed block, a Z-axis motor arranged at one end of the Z-axis screw, a support table fixedly arranged on the Z-axis motor, a rotating motor arranged on the support table, and a carrier arranged at the output end of the rotating motor, two first limit blocks are arranged on the carrier, the first limit blocks are arranged in an L shape, and the openings of the two first limit blocks are arranged back to back, two second limit blocks are arranged on one side of the two first limit blocks, the structure of the second limit blocks is the same as that of the first limit blocks, the openings of the two second limit blocks are arranged back to back, and the distance between the two second limit blocks is greater than the distance between the two first limit blocks.

2. The wafer carrier dimension measuring device according to claim 1, characterized in that: The two-axis moving assembly includes an X-axis motor arranged on the frame, an X-axis screw rod arranged at the output end of the X-axis click, a first support plate screwed on the X-axis screw rod, a Y-axis motor arranged on the first support plate, a Y-axis screw rod arranged at the output end of the Y-axis motor, and a second support plate screwed on the Y-axis screw rod.

3. The wafer carrier dimension measuring device according to claim 2, characterized in that: The length direction of the X-axis lead screw is perpendicular to the length direction of the Y-axis lead screw.

4. The wafer carrier dimension measuring device according to claim 1, characterized in that: One end of the Z-axis lead screw away from the Z-axis motor is rotatably connected to the support platform.

5. The wafer carrier dimension measuring device according to claim 2, characterized in that: The length direction of the Z-axis lead screw is perpendicular to the horizontal plane, and is perpendicular to the length directions of the X-axis lead screw and the Y-axis lead screw.

6. The wafer carrier dimension measuring device according to claim 1, characterized in that: The detection component includes a visual detector and at least four fill lights respectively arranged on two sides of the visual detector.

7. The wafer carrier dimension measuring device according to claim 6, characterized in that: The output directions of the two visual detectors are arranged opposite to each other and are both directed toward the carrier.

8. The wafer carrier dimension measuring device according to claim 6, characterized in that: The two fill-in lights on the same side of the visual detector are arranged outwardly, and the angle between the lamp surfaces of the two fill-in lights is greater than 180 degrees.

9. A calculation method for a wafer carrier size measurement device, characterized in that: The calculation method of the wafer carrier size measurement device comprises the following steps: (1) Acquire an image; (2) Obtain the ROI area and its location information in the image to improve the efficiency of image processing; (3) Perform edge analysis on the ROI area. First, perform image denoising and smoothing, then perform threshold segmentation. After the image is binarized, edge line detection is performed on the processed image, and the position information of the edge points in the ROI area is maintained. (4) The position coordinate information of the ROI area and the position coordinate information of the edge line are combined to calculate the actual pixel point information of the edge line in the ROI area; (5) Calculate the pixel information of the edge line in the coordinate system with the center of the image as the coordinate system, and combine it with the position information of the axis to establish a reference system with the reference system of all edge lines as the axis; (6) The distance of the product is obtained by calculating the relative difference in the position information of the edge axis reference system on both sides of the product.

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