A wafer carrier size measurement device and its calculation method

Abstract

A size measuring device for a wafer carrier and its calculation method, which are used to perform appearance size detection calculation and slot height size detection calculation on a wafer carrier. The size measuring device for the wafer carrier includes a frame, at least two two-axis moving components oppositely 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 lead screw screwed on the fixed block, a Z-axis motor, a support table, a rotating motor, and a carrier table. The second limiting block can limit the wafer carrier with a larger specification compared to the first limiting block, so that the measuring device can detect the two wafer carriers with different specifications, thereby improving the applicability of the measuring device.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and particularly to a size measurement device for a wafer carrier and its calculation method. Background Art

[0002] The size detection of a wafer carrier is an important link in the semiconductor manufacturing process. The main purpose is to ensure that the size of the wafer carrier meets the design requirements to guarantee the stability and accuracy of the wafer during the processing. Therefore, the detection device for the wafer carrier is particularly important. For example, Chinese Patent CN201020146994.5 discloses a wafer fixing frame detection device, which mainly sets a turntable driven by a driving component to rotate on a detection base. A laser emitter is set on the first positioning frame of the base, and an image capture device is set on the second positioning frame. The laser emitter and the image capture device have an included angle relative to the turntable, and a computer with an image analysis and judgment function is provided. Thus, during the rotation of the wafer fixing frame placed on the turntable for one week, the laser emitter projects laser at each angle interval of the rotating wafer fixing frame, the image capture device captures images of each laser projection, and then the computer quickly and accurately judges whether the shape specifications such as the appearance size, thickness, and flatness of the wafer fixing frame meet the requirements according to the positioning signal of the driving component and the image data captured by the image capture device. However, this device requires the laser emitter to project laser at each angle interval of the rotating wafer fixing frame, resulting in low detection efficiency. Summary of the Invention

[0003] In view of this, the present invention provides a size measurement device for a wafer carrier and its calculation method to solve the above problems.

[0004] A size measuring device for a wafer carrier, which is used to perform appearance size detection calculation and slot height size detection calculation on 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 size measuring device for the wafer carrier includes a frame, at least two two-axis moving components oppositely 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 lead screw screwed on the fixed block, a Z-axis motor arranged at one end of the Z-axis lead screw, a support platform fixedly arranged on the Z-axis motor, a rotating motor arranged on the support platform, and a carrier table arranged at the output end of the rotating motor. Two first limit blocks are arranged on the carrier table, the first limit blocks are arranged in an L shape, and the openings of the two first limit blocks face away from each other. Two second limit blocks are arranged on one side of the two first limit blocks, and the structure of the second limit block is the same as that of the first limit block. The openings of the two second limit blocks face away from each other, and the distance between the two second limit blocks is greater than the distance between the two first limit blocks.

[0005] Further, the two-axis moving component includes an X-axis motor arranged on the frame, an X-axis lead screw arranged at the output end of the X-axis motor, a first support plate screwed on the X-axis lead screw, a Y-axis motor arranged on the first support plate, a Y-axis lead screw arranged at the output end of the Y-axis motor, and a second support plate screwed on the Y-axis lead screw.

[0006] Further, the length direction of the X-axis lead screw is perpendicular to the length direction of the Y-axis lead screw.

[0007] Further, the end of the Z-axis lead screw far from the Z-axis motor is rotatably connected to the support platform.

[0008] Further, the length direction of the Z-axis lead screw is perpendicular to the horizontal plane and perpendicular to the length directions of the X-axis lead screw and the Y-axis lead screw.

[0009] Further, the detection component includes a vision detector and at least four supplementary light lamps respectively arranged on both sides of the vision detector.

[0010] Further, the output directions of the two vision detectors are oppositely arranged and both face the carrier table.

[0011] Further, the two supplementary light lamps on the same side of the vision detector are arranged outwardly, and the included angle between the light surfaces of the two supplementary light lamps is greater than 180 degrees.

[0012] Further, the calculation method of the size measuring device of the wafer carrier includes the following steps:

[0013] (1) Obtain an image;

[0014] (2) Obtain the ROI region and its position information in the image to improve the efficiency of image processing;

[0015] (3) Conduct edge analysis on the ROI region. First, perform image denoising and smoothing, then perform threshold segmentation. After binarizing the image, perform edge straight line detection on the processed image and maintain the position information of the edge points in the ROI region;

[0016] (4) Combine the position coordinate information of the ROI region and the position coordinate information of the edge straight line to calculate the actual pixel point information of the edge straight line in the ROI region;

[0017] (5) Calculate the pixel point information of the edge straight line in the coordinate system with the image center as the coordinate system, and combine the position information of the axis to establish a reference system that unifies all the reference systems of the edge straight lines into the reference system of the axis;

[0018] (6) Obtain the distance of the product by calculating the relative difference in the position information of the position edge axis reference systems on both sides of the product.

[0019] Compared with the prior art, the size measuring device of the wafer carrier and its calculation method provided by the present invention drive 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 stage to perform lifting and rotation. In this way, 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, the second limit block can limit the wafer carrier with a larger specification compared to the first limit block, so that the measuring device can detect two wafer carriers with different specifications, thereby improving the applicability of the measuring device. Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of the size measuring device of the wafer carrier provided by the present invention.

[0021] Figure 2 It is a schematic step diagram of the size measuring device of the wafer carrier and its calculation method provided by the present invention.

[0022] Figure 3 For Figure 1Schematic structural diagram of a wafer carrier of a size measuring device for a wafer carrier.

[0023] Figure 4 For Figure 1 Schematic structural diagram of a two-axis moving component and a detection component of a size measuring device for a wafer carrier.

[0024] Figure 5 For Figure 1 Schematic structural diagram of a lifting and rotating component of a size measuring device for a wafer carrier.

[0025] Explanation of reference numerals in the drawings: frame 10, two-axis moving component 20, X-axis motor 21, X-axis lead screw 22, first support plate 23, Y-axis motor 24, Y-axis lead screw 25, second support plate 26, lifting and rotating component 30, fixed block 31, Z-axis lead screw 32, Z-axis motor 33, support platform 34, rotating motor 35, carrier stage 36, first limit block 37, second limit block 38, detection component 40, vision detector 41, fill light 42, wafer carrier 50, carrier frame 51, stop post 52, card slot 53, tail plate 54. Detailed implementation manners

[0026] The following further details the specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein does not limit the protection scope of the present invention.

[0027] As Figure 1 shown, it is a schematic structural diagram of a size measuring device for a wafer carrier provided by the present invention. The size measuring device for the wafer carrier includes a frame 10, at least two two-axis moving components 20 oppositely 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 size measuring device for the wafer carrier further includes some other functional modules, such as a power supply module, a gas supply module, etc., which are well-known technologies to those skilled in the art and will not be elaborated herein one by one.

[0028] Please refer to Figures 2 to 5, the size measurement device and its calculation method for the wafer carrier are used to perform appearance size detection and slot height size detection on a wafer carrier 50. The wafer carrier 50 includes a carrier frame 51, at least four retaining posts 52 provided on both sides of the carrier frame 51, and a number of card slots 53 opened on both sides of the carrier frame 51. The number of the card slots 53 is used to place wafers, and the wafers are clamped by the retaining 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.

[0029] The frame 10 is used to carry the above-mentioned various components, so that various cooperations can be completed between them, so as to perform size detection on the wafer carrier 50.

[0030] The two-axis moving assembly 20 includes an X-axis motor 21 arranged on the frame 10, an X-axis lead screw 22 arranged at the output end of the X-axis click 21, a first support plate 23 screwed on the X-axis lead screw 22, a Y-axis motor 24 arranged on the first support plate 23, a Y-axis lead screw 25 arranged at the output end of the Y-axis motor 24, and a second support plate 26 screwed on the Y-axis lead screw 25.

[0031] The X-axis motor 21 can drive the X lead screw 22 to rotate, and the Y-axis motor 24 can drive the Y-axis lead screw 25 to rotate, so as to drive the first support plate 23 and the second support plate 26 screwed on the X-axis motor 21 and the Y-axis lead screw 25 to move. The length direction of the X-axis lead screw 22 is perpendicular to the length direction of the Y-axis lead screw 25, and the detection assembly 40 is arranged on the second support plate 26. In this way, the driving of the X-axis motor 21 and the Y-axis motor 24 can drive the detection assembly 40 to move in a two-dimensional plane, so as to control the distance and orientation between the two detection assemblies 40 and the wafer carrier 50.

[0032] The lifting and rotating assembly 30 includes a fixed block 31 fixedly arranged on the frame 10, a Z-axis lead screw 32 screwed on the fixed block 31, a Z-axis motor 33 arranged at one end of the Z-axis lead screw 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.

[0033] One end of the Z-axis lead screw 32 far from the Z-axis motor 33 is rotatably connected to the support table 34. The Z-axis motor 33 can drive the Z-axis lead screw 32 to rotate, thereby driving the support table 34 to move. The length direction of the Z-axis lead screw 32 is perpendicular to the horizontal plane and perpendicular to the length directions of the X-axis lead screw 22 and the Y-axis lead screw 25. In this way, the moving direction of the support table 34 is perpendicular to the moving plane of the two-axis moving assembly 20.

[0034] The rotation motor 35 can drive the carrier table 36 to rotate, thereby driving the wafer carrier 50 placed on the carrier table 36 to rotate. When the wafer carrier 50 placed on the carrier table 36 rotates to have its opening facing one of the detection components 40, this 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 card slot 53.

[0035] Two first limit blocks 37 are provided on the carrier table 36. The first limit blocks 37 are arranged in an L shape, and the openings of the two first limit blocks 37 face away from each other. In this way, the two tail plates 54 on the wafer carrier 50 can be clamped in the two first limit blocks 37, thereby completing the limiting function of the wafer carrier 50 to stabilize the wafer carrier 50 during subsequent lifting and rotating operations.

[0036] Two second limit blocks 38 are provided on one side of the two first limit blocks 37. The structure of the second limit block 38 is the same as that of the first limit block 37. The openings of the two second limit blocks 38 face away from each other, 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-sized wafer carrier 50, so that the measuring device can detect two different-sized wafer carriers, thereby improving the applicability of the measuring device.

[0037] The detection component 40 includes a vision detector 41 provided on the second support plate 26 and at least four supplementary light lamps 42 respectively provided on both sides of the vision detector 41.

[0038] The vision detector 41 is a device that uses machine vision technology to detect objects. It captures images of objects through an image acquisition device (such as CMOS and CCD cameras) and transmits these image signals to a dedicated image processing system. The image processing system performs various operations on these signals, extracts the features of the target, and performs data display.

[0039] The output directions of the two vision detectors 41 are oppositely arranged and both face the stage 36. In this way, the two vision detectors 41 can cooperate with the two-axis moving assembly 20 and the lifting and rotating assembly 30 to measure the wafer carrier placed on the stage 36.

[0040] The two fill lights 42 on the same side of the vision detector 41 are arranged to expand outward, that is, the included angle between the light surfaces of the two fill lights 42 is greater than 180 degrees. In this way, the light can be diffused and irradiated to fully irradiate the wafer carrier 50, so as to make up for the insufficient light in the detection operation and improve the detection quality of the vision detector 41.

[0041] The two relatively arranged detection assemblies 40 can simultaneously perform front-to-back detection on the wafer carrier 50. In this way, the lifting and rotating assembly 30 only needs to rotate the wafer carrier 50 by 180 degrees to complete full-size detection of the wafer carrier 50, thereby improving the detection efficiency of the measuring device.

[0042] The steps of the calculation method of the size measuring device for the wafer carrier are as follows:

[0043] (1) Obtain an image.

[0044] Capture an image of the wafer carrier 50 through the vision detector 41 and upload the image to the computer.

[0045] (2) Obtain the ROI region and its position information in the image to improve the efficiency of image processing.

[0046] After image processing, outline the regions that need special attention from the image. These regions can be marked in ways such as rectangles, circles, ellipses or irregular polygons. The marked regions are the ROI regions. (3) Perform edge analysis on the ROI region. First, perform image denoising and smoothing, then perform threshold segmentation, binarize the image, and then perform edge straight line detection on the processed image while maintaining the position information of the edge points in the ROI region.

[0047] First, use a filter to eliminate noise and denoise and smooth the image.

[0048] Then, according to the product characteristics and the measurement environment (using a backlight), set a fixed grayscale threshold parameter. If the grayscale value on the image is higher than the threshold parameter, take white, and if the grayscale value on the image is lower than the threshold parameter, take black, so as to eliminate false edges, segment the object from the background, and facilitate user observation.

[0049] Calculate the gradients of the image in the X and Y directions according to the Sobel operator, and then calculate the gradient magnitude. Two thresholds are obtained based on the accuracy requirement. If the gradient magnitude is greater than the high threshold, the pixel is marked as a "strong edge". If the gradient magnitude 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 magnitude is less than the low threshold, the pixel is ignored. Since this calculation method is used to detect the groove width of the slot 53 on the wafer carrier 50, the edge point information of the slot 53 is hardly an ideal straight line, and the approximate straight lines on both edges of the slot 53 are not necessarily parallel. Therefore, calculating the size by the distance between points will result in a large error. By fitting a straight line, the characteristics of the particle unevenness of the edge points can be neutralized, making the calculation result more reasonable. The method of fitting a straight line is as follows: Use the Hough transform to extract a straight line from the edge image. By converting the pixel points from the image space to the parameter control, find the cumulative value with the largest number of points in the polar coordinate space, determine a straight line, and then convert the result in the polar coordinate space back to the image space to draw the detected straight line.

[0050] While obtaining the position information of the edge straight line, maintain the position information of the edge points in the ROI region. (4) Combine the position coordinate information of the ROI region and the position coordinate information of the edge straight line to calculate the actual pixel point information of the edge straight line in the ROI region.

[0051] The position coordinate information of the ROI region obtained in the second step and the position coordinate information of the edge points are calculated by identifying them in pixel mode, with pixels (px) as the unit. Therefore, it is necessary to convert the position coordinate information of the ROI region and the position coordinate information of the edge points, and use the internal parameters of the camera (known information) to obtain the actual position information of the edge points in the ROI region, with the unit of (um or mm, etc.). (5) Calculate the pixel point information of the edge straight line in the coordinate system with the image center as the origin, and combine the position information of the axis to establish a reference system that unifies all the reference systems of the edge straight lines to the reference system of the axis.

[0052] On the premise of taking the image center as the coordinate system, establish a first reference system, and calculate the position coordinates of the edge straight line in the image, that is, the distance d between the edge straight line and the Y-axis in this coordinate system. Then, on the premise of taking an origin on the axis as the coordinate system, establish a second reference system, and obtain the position information of the image center, that is, the distance D between the image center and the Y-axis in this coordinate system.

[0053] (6) Obtain the distance of the product by calculating the relative difference in the position information of the position edge axis reference systems on both sides of the product.

[0054] 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). Thus, the distance between the two edge lines is: (d1 + D1) - (d2 + D2).

[0055] Compared with the prior art, the size measurement device and its calculation method of the wafer carrier provided by the present invention drive 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 stage 36 to perform lifting and rotation. In this way, 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, the second limit block 38 can limit the wafer carrier 50 with a larger specification compared with the first limit block 37, so that the measurement device can detect two wafer carriers with different specifications, thereby improving the applicability of the measurement device.

[0056] The above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements or improvements within the spirit of the present invention are all covered within the scope of the claims of the present invention.

Claims

1. A size measuring device for a wafer carrier, which is used to detect and calculate the appearance size and the groove height size 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 size measuring device for the wafer carrier is characterized in that: the size measuring device for the wafer carrier includes a frame, at least two two-axis moving components oppositely 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 lead screw screwed on the fixed block, a Z-axis motor arranged at one end of the Z-axis lead screw, a support platform fixedly arranged on the Z-axis motor, a rotating motor arranged on the support platform, and a carrier table arranged at the output end of the rotating motor. Two first limit blocks are arranged on the carrier table. The first limit blocks are L-shaped, and the openings of the two first limit blocks face away from each other. 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 face away from each other, and the distance between the two second limit blocks is greater than the distance between the two first limit blocks. The two oppositely arranged detection components detect the wafer carrier simultaneously from the front and the back.

2. The size measuring apparatus for a wafer carrier according to claim 1, wherein: The two-axis moving component includes an X-axis motor arranged on the frame, an X-axis lead screw arranged at the output end of the X-axis motor, a first support plate screwed on the X-axis lead screw, a Y-axis motor arranged on the first support plate, a Y-axis lead screw arranged at the output end of the Y-axis motor, and a second support plate screwed on the Y-axis lead screw.

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

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

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

6. The size measuring device for a wafer carrier according to claim 1, characterized in that: The detection component includes a vision detector and at least four supplementary light lamps respectively arranged on both sides of the vision detector.

7. The size measuring device for a wafer carrier according to claim 6, characterized in that: The output directions of the two vision detectors are oppositely arranged and both face the carrier table.

8. The size measuring device for a wafer carrier according to claim 6, wherein: The two supplementary light lamps on the same side of the vision detector are arranged outward, and the included angle between the light surfaces of the two supplementary light lamps is greater than 180 degrees.

9. A calculation method for a dimension measurement device of a wafer carrier according to any one of claims 1 to 8, characterized in that: The calculation method of the size measuring device for the wafer carrier includes the following steps: (1) Obtain an image; (2) Obtain the ROI region and its position information in the image to improve the efficiency of image processing; (3) Perform edge analysis on the ROI region. First, perform image denoising and smoothing, then perform threshold segmentation, binarize the image, and then perform edge straight line detection on the processed image while maintaining the position information of the edge points in the ROI region. (4) Combine the position coordinate information of the ROI region and the position coordinate information of the edge straight line to calculate the actual pixel point information of the edge straight line in the ROI region; (5) Calculate the pixel point information of the edge straight line in the coordinate system with the image center as the coordinate system. Combine the position information of the axis to establish a reference system that unifies all the reference systems of the edge straight lines into the reference system of the axis. On the premise that the center of the image is used as the coordinate system, establish the first reference system. On the premise that an origin on the axis is used as the coordinate system, establish the second reference system, and obtain the position information of the image center; (6) Obtain the distance of the product by calculating the relative difference in the position information of the position edge axis reference systems on both sides of the product. Select the position information of two edge straight lines in the first reference system and the second reference system respectively to obtain the edge straight line 1: (d1, D1), the edge straight line 2 (d2, D2), and the distance between the two edge straight lines is: (d1 + D1) - (d2 + D2).

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