Device and method for centering wafer in cavity

Abstract

The present invention relates to the field of wafer positioning technology, and specifically to a device and method for centering a wafer in a cavity. The present invention comprises a base plate, a wafer carrier is installed on the upper surface of the base plate near the middle position, a wafer center positioning fixture is fixedly installed on the upper surface of the wafer carrier, a baffle is fixedly connected to the upper surface of the wafer carrier near one side position, a translation base plate is installed on the upper surface of the wafer carrier near one side position of the baffle, a visual photography system is provided on the upper surface of the base plate near the corner position, and a positioning card is installed above the base plate and near one side position of the wafer center positioning fixture. The present invention uses a visual photography system, visual software, and mechanical motion components to control the error between the center position of the wafer and the center position in the cavity within the error range allowed by wafer processing, so that the wafer processing of semi-automatic or manual semiconductor equipment meets the requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer positioning, and in particular to a device and method for centering a wafer in a cavity. Background Art

[0002] A wafer refers to a silicon chip used to make silicon semiconductor circuits. Its original material is silicon. High-purity polycrystalline silicon is dissolved and doped with silicon crystal seeds, and then slowly pulled out to form cylindrical single crystal silicon. After grinding, polishing, and slicing, the silicon crystal rod forms a silicon wafer, which is also a wafer. The main processing methods for wafers are sheet processing and batch processing. As the feature size of semiconductors becomes smaller and smaller, and processing and measurement equipment becomes more and more advanced, new data characteristics have emerged in wafer processing.

[0003] In the prior art, semiconductor processing of wafers, such as gluing, developing and bonding, is carried out on a cavity carrier. Before the wafer is sent into the cavity, it must first be centered by a wafer center positioning device to find the center point of the wafer, and then sent into the cavity by a robot so that the center of the wafer coincides with the center of the carrier in the cavity before processing. However, for semi-automatic or manual semiconductor equipment, there is no robot and wafer center positioning device. The wafer is manually placed in the cavity, relying only on visual observation or simple mechanical positioning, resulting in a large error between the center of the wafer and the center of the carrier in the cavity, affecting the wafer processing effect. Summary of the Invention

[0004] The object of the present invention is to provide a device and method for centering a wafer in a cavity, so as to solve the problems raised in the above background technology.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] The center positioning device of the wafer in the cavity includes a base plate, a wafer carrier is installed on the upper surface of the base plate near the middle position, a wafer center positioning fixture is fixedly installed on the upper surface of the wafer carrier, a baffle is fixedly connected to the upper surface of the wafer carrier near one side, a translation base plate is installed on the upper surface of the wafer carrier near one side of the baffle, a visual photography system is provided on the upper surface of the base plate near the corner position, a left positioning block is installed above the base plate and near one side of the wafer center positioning fixture, and a right positioning block is installed above the base plate and near the other side of the wafer center positioning fixture.

[0007] Preferably, the visual photography system includes a translation axis motion guide rail slider, the translation axis motion guide rail slider is slidably mounted on the upper surface of the bottom plate, one end of the translation axis motion guide rail slider is fixedly connected to a Z-axis mounting piece, and the outer side wall of the Z-axis mounting piece is movably mounted near the upper end thereof.

[0008] A translation axis motor is installed on the upper surface of the bottom plate near one end of the translation axis motion guide rail slider, and the output end of the translation axis motor is connected to the translation axis motion guide rail slider.

[0009] Preferably, the outer side wall of the Z-axis motion guide rail slider is fixedly connected to a mounting plate, the outer side wall of the mounting plate is fixedly mounted with a camera, the bottom surface of the camera is fixedly connected with a lens, and the outer side wall of the Z-axis mounting part and the position below the Z-axis motion guide rail slider is fixedly mounted with a light source mounting adjustment part.

[0010] Preferably, a Z-axis motor is fixedly mounted on the outer wall of the Z-axis mounting piece and located below the light source mounting adjustment piece, and a light source is mounted on the outer wall of the Z-axis mounting piece and located directly below the lens.

[0011] Preferably, a left servo translation arm is fixedly mounted on one side of the left positioning block, and a right servo translation arm is mounted on one side of the right positioning block.

[0012] Preferably, a spindle motor is installed near the middle of the upper surface of the base plate, an exhaust box is installed near one side of the upper surface of the base plate near the spindle motor, and a liquid extractor is fixedly installed near one side of the upper surface of the base plate near the exhaust box.

[0013] Preferably, the outer side wall of the translation base plate is installed with a left servo translation mechanism and a right servo translation structure, a nozzle wetting and waste discharge assembly is fixedly installed under the right servo translation arm, a front side washing and waste discharge box assembly is fixedly installed under the left servo translation arm, and a cavity leakage connection plate wafer center positioning device is fixedly connected to the bottom surface of the base plate. The specific steps of the method are as follows:

[0014] Step 1: Place the wafer on the left and right positioning blocks. The left servo translation mechanism drives the left positioning block on the left servo translation arm to move rightward, and the right servo translation mechanism drives the right positioning block on the right servo translation arm to move leftward, thereby preliminarily clamping and fixing the wafer.

[0015] Step 2: The Z-axis mounting assembly is driven by the translation motor to translate toward the wafer on the translation guide rail. The camera then takes a picture of the wafer edge to locate the wafer center. This is compared with the wafer stage center position to calculate the positional error between the two. This error value is sent to the vision software, which then calculates the required translation of the wafer in the X and Y directions.

[0016] Step 3: The vision software drives the left servo translation mechanism and the right servo translation structure to move the wafer in the X and Y directions;

[0017] Step 4: After the translation is completed, the visual camera system takes another picture of the edge of the wafer to find the center position of the wafer after translation and calculate the error with the center of the wafer stage. If the error is within the error range allowed for wafer processing, the center positioning of the wafer in the cavity is completed and wafer processing begins.

[0018] Beneficial effects of the present invention:

[0019] 1. The present invention places the wafer on the left positioning block and the right positioning block, cooperates with the left servo translation mechanism, and the left positioning block and the right servo translation structure and the right positioning block to move toward each other, thereby preliminarily clamping and fixing the wafer. Then, the edge of the wafer is photographed by a visual photography system, and the required translation of the wafer in the X and Y directions is calculated in conjunction with the visual software. Similarly, the wafer is translated in the X and Y directions and rotated, so that the position error between the center of the wafer and the center of the cavity is controlled within the error range allowed by wafer processing, thereby meeting the requirements of wafer processing of semi-automatic or manual semiconductor equipment.

[0020] 2. In the present invention, the edge of the wafer can be photographed through the visual photography system to find the center position of the wafer, the notch or flat edge position of the wafer edge, and with the help of visual software, the wafer can be moved in the X and Y directions to approach the center position in the cavity, and the wafer can be rotated so that the notch or flat edge of the wafer edge is in the position required for processing. The wafer can be repeatedly centered until the error between the center position of the wafer and the center position of the wafer carrier is within the allowable error range of wafer processing.

[0021] 3. In the present invention, the visual photography system realizes horizontal movement through the translation axis motion guide slider in conjunction with the translation axis motor, moves to the top of the wafer to take pictures, and returns to its original position after the picture is taken, without affecting the wafer processing. The visual photography system realizes Z-axis movement through the Z-axis motor in conjunction with the Z-axis motion guide slider, and can accurately adjust the height of the visual system to the wafer to realize measurement of wafers of different sizes. The light source can be fine-tuned to ensure clear pictures. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 It is a partial structural schematic diagram of the present invention;

[0025] Figure 3It is a structural schematic diagram of another perspective of the present invention;

[0026] Figure 4 It is a structural schematic diagram of the exhaust box and the liquid extractor in the present invention;

[0027] Figure 5 This is a structural diagram of the bottom plate and the cavity leakage connection plate in the present invention;

[0028] Figure 6 It is a structural diagram of the visual photography system in the present invention.

[0029] The reference numerals in the figures are as follows:

[0030] 1. Wafer stage; 2. Left positioning block; 3. Left servo translation arm; 4. Wafer center positioning fixture; 5. Right positioning block; 6. Right servo translation arm; 7. Mounting plate; 8. Left servo translation mechanism; 9. Right servo translation structure; 10. Lens; 11. Light source; 12. Z-axis motor; 13. Light source installation adjustment part; 15. Z-axis motion guide slider; 16. Z-axis mounting part; 17. Translation axis motor; 18. Translation axis motion guide slider; 19. Camera; 20. Baffle; 21. Bottom plate; 22. Nozzle wetting and waste discharge assembly; 23. Front side washing and waste discharge box assembly; 24. Exhaust box; 25. Spindle motor; 26. Translation bottom plate; 27. Liquid extractor; 28. Cavity leakage connection plate. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] Wafer centering device in the cavity, such as Figures 1-6 As shown, it includes a base plate 21, a wafer carrier 1 is installed on the upper surface of the base plate 21 near the middle position, a wafer center positioning fixture 4 is fixedly installed on the upper surface of the wafer carrier 1, a baffle 20 is fixedly connected to the upper surface of the wafer carrier 1 near one side, a translation base plate 26 is installed on the upper surface of the wafer carrier 1 near one side of the baffle 20, a visual photography system is provided on the upper surface of the base plate 21 near the corner position, a left positioning block 2 is installed above the base plate 21 and near one side of the wafer center positioning fixture 4, and a right positioning block 5 is installed above the base plate 21 and near the other side of the wafer center positioning fixture 4.

[0033] A left servo translation arm 3 is fixedly mounted on one side of the left positioning block 2 , and a right servo translation arm 6 is mounted on one side of the right positioning block 5 .

[0034] By adding a left positioning block 2, a right positioning block 5, a wafer center positioning fixture 4 and a visual photography system in the glue coating chamber, the arc diameter of the left positioning block 2 and the right positioning block 5 is equal to the wafer diameter, the left positioning block 2 is installed on the left servo translation arm 3, and the right positioning block 5 is installed on the right servo translation arm 6. The visual photography system is installed in the empty space in the upper left corner of the glue coating chamber. The wafer center positioning fixture 4 is processed as one piece and presents two sections of cylinders with different diameters. The lower end cylinder is coaxial with the wafer carrier 1, and the upper end cylinder has the same diameter as the wafer diameter. The center of the wafer center positioning fixture 4 is the center of the wafer carrier 1.

[0035] The left servo translation mechanism 8 drives the left positioning block 2 on the left servo translation arm 3 to move to the right. At the same time, the right servo translation structure 9 drives the right positioning block 5 on the right servo translation arm 6 to move to the left. The left positioning block 2 and the right positioning block 5 are adjusted forward and backward so that the arcs of the left positioning block 2, the wafer center positioning fixture 4, and the right positioning block 5 coincide. Then the left positioning block 2 and the right positioning block 5 are fixed so that the left positioning block 2 and the right positioning block 5 do not need to be adjusted in the Y direction during subsequent use. The heights of the left positioning block 2 and the right positioning block 5 are the same as the height of the wafer center positioning fixture 4. After the center positioning is completed, the wafer can be in the cavity without having to descend in the Z direction.

[0036] The spindle motor 25 is installed near the middle of the upper surface of the bottom plate 21, and an exhaust box 24 is installed on the side of the upper surface of the bottom plate 21 near the spindle motor 25. A liquid extractor 27 is fixedly installed on the side of the upper surface of the bottom plate 21 near the exhaust box 24. The outer wall of the translation bottom plate 26 is installed with a left servo translation mechanism 8 and a right servo translation structure 9. A nozzle wetting and waste discharge assembly 22 is fixedly installed below the right servo translation arm 6, and a front washing and waste discharge box assembly 23 is fixedly installed below the left servo translation arm 3. The bottom plate 21 The bottom surface is fixedly connected to a cavity leakage connecting plate 28, and the spindle motor 25 can drive the wafer carrier 1 to rotate, so as to facilitate the rotation adjustment of the wafer placed on the wafer carrier 1. The exhaust box 24 cooperates with the liquid extractor 27 to assist in exhausting and extracting liquid in the subsequent wafer coating operation. The waste liquid generated during the coating process can be discharged from the glue nozzle wetting and waste discharge component 22. The glue can be sprayed on the wafer through the right servo translation structure 9 in combination with the glue coating nozzle. The glue leaked during the coating process can be received by the cavity leakage connecting plate 28.

[0037] The visual photography system includes a translation axis motion guide rail slider 18, which is slidably installed on the upper surface of the base plate 21. One end of the translation axis motion guide rail slider 18 is fixedly connected to the Z-axis mounting member 16. The Z-axis motion guide rail slider 15 is movably installed on the outer wall of the Z-axis mounting member 16 near the upper end. A translation axis motor 17 is installed on the upper surface of the base plate 21 near one end of the translation axis motion guide rail slider 18, and the output end of the translation axis motor 17 is connected to the translation axis motion guide rail slider 18.

[0038] The outer side wall of the Z-axis motion guide rail slider 15 is fixedly connected to the mounting plate 7, the outer side wall of the mounting plate 7 is fixedly mounted with a camera 19, the bottom surface of the camera 19 is fixedly connected with a lens 10, the outer side wall of the Z-axis mounting member 16 and a light source mounting adjustment member 13 is fixedly mounted below the Z-axis motion guide rail slider 15, the outer side wall of the Z-axis mounting member 16 and a Z-axis motor 12 is fixedly mounted below the light source mounting adjustment member 13, and the outer side wall of the Z-axis mounting member 16 and a light source 11 is mounted directly below the lens 10.

[0039] Specifically, in the visual photography system, the mounting plate 7 fixes the camera 19 on the visual system Z-axis motion guide rail slider 15. The camera 19 and the lens 10 are fixed together by their own threads. The Z-axis motor 12 can drive the visual system Z-axis motion guide rail slider 15 to move up and down on the guide rail, thereby driving the camera 19 and the lens 10 to move up and down to adjust the distance between the lens 10 and the light source 11. The light source 11 is fixed to the Z-axis mounting member 16 through the light source mounting adjustment member 13. The light source mounting adjustment member 13 is provided with a waist groove, which can adjust the distance between the light source 11 and the wafer to take clear pictures of the wafer edge.

[0040] The Z-axis mounting part 16 is fixedly mounted on the translation axis motion guide slider 18, and the translation axis motor 17 can drive the Z-axis mounting part 16 to translate on the translation axis motion guide slider 18 toward the wafer direction, so as to take pictures of the wafer edge and then locate the wafer center. After the wafer center is located, the translation axis motor 17 drives the Z-axis mounting part 16 to translate on the translation axis motion guide slider 18 away from the wafer direction and leave the top of the wafer.

[0041] The visual camera system can be used to take pictures of the edge of the wafer, find the center position of the wafer, the notch or flat edge position of the wafer edge, and use visual software to calculate the error between the center position of the wafer and the center position in the cavity and send it to the visual software. The wafer can move in the X and Y directions to approach the center position in the cavity. The wafer can be rotated so that the notch or flat edge on the edge of the wafer is in the position required for processing. The wafer can be repeatedly centered until the error between the center position of the wafer and the center position of the wafer carrier 1 is within the allowable error range of wafer processing. The visual camera system realizes horizontal movement through the translation axis motion guide slider 18 and the translation axis motor 17, moves to the top of the wafer to take pictures, and returns to its original position after the picture is taken without affecting the wafer processing. The visual camera system realizes Z-axis movement through the Z-axis motor 12 and the Z-axis motion guide slider 15, which can accurately adjust the height of the visual system to the wafer to realize measurement of wafers of different sizes. The light source 11 can be fine-tuned to ensure clear pictures.

[0042] Working principle: Place the wafer on the left positioning block 2 and the right positioning block 5. The visual camera system has established the correspondence between the coordinates of the camera 19 and the coordinate system of the wafer carrier 1 through the calibration method before measurement. Then, take a picture of the edge of the wafer to find the center position of the wafer. By comparing it with the center position of the wafer carrier 1, the position error between the two is calculated, and the error value is sent to the visual software. The visual software calculates the required translation of the wafer in the X and Y directions, and drives the translation device to translate in the X and Y directions. After the translation is completed, the visual camera system takes a picture of the edge of the wafer again to find the center position of the wafer after translation, and calculates the error with the center of the wafer carrier 1. If the error is within the error range allowed for wafer processing, the center positioning of the wafer in the cavity is completed, and the center positioning device descends in the Z direction to make the wafer fall into the cavity, and wafer processing begins;

[0043] If the error exceeds the allowable error range for wafer processing, the error is sent to the vision software, which calculates the required translation of the wafer in the X and Y directions and drives the translation device to translate in the X and Y directions until the error is within the allowable error range for wafer processing.

[0044] Among them, the special wafer processing technology requires that after the wafer center positioning is completed, the notch or flat edge of the wafer edge is at a certain position. The device can calculate the position of the notch or flat edge of the wafer edge while visually calculating the error between the wafer center and the center of the cavity, and obtain the angle between the position direction and the X direction or Y direction. After the center positioning of the wafer in the cavity is completed, the wafer rotating part drives the wafer to rotate on the wafer carrier 1 so that the notch or flat edge of the wafer edge is at the position required for processing.

[0045] A method for centering a wafer in a cavity, wherein the method comprises the following steps:

[0046] Step 1: Place the wafer on the left positioning block 2 and the right positioning block 5. The left servo translation mechanism 8 drives the left positioning block 2 on the left servo translation arm 3 to move rightward, and the right servo translation mechanism 9 drives the right positioning block 5 on the right servo translation arm 6 to move leftward to initially clamp and fix the wafer.

[0047] Step 2: The Z-axis mounting member 16 is driven by the translation axis motor 17 to translate on the translation axis motion guide slider 18 toward the wafer. The camera 19 then takes a picture of the wafer edge to find the wafer center position. The center position is compared with the center position of the wafer stage 1 to calculate the position error between the two. The error value is sent to the vision software, which calculates the required translation of the wafer in the X and Y directions.

[0048] Step 3: The vision software drives the left servo translation mechanism 8 and the right servo translation mechanism 9 to move the wafer in the X and Y directions;

[0049] Step 4: After the translation is completed, the visual camera system takes a picture of the edge of the wafer again to find the center position of the wafer after translation, and calculates the error with the center of the wafer carrier 1. If the error is within the error range allowed for wafer processing, the center positioning of the wafer in the cavity is completed and wafer processing begins.

[0050] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A device for centering a wafer in a cavity, comprising a base plate (21), characterized in that: A wafer carrier (1) is mounted near the middle of the upper surface of the base plate (21), a wafer center positioning fixture (4) is fixedly mounted on the upper surface of the wafer carrier (1), a baffle (20) is fixedly connected to the upper surface of the wafer carrier (1) near one side, a translation base plate (26) is mounted near one side of the upper surface of the wafer carrier (1) near the baffle (20), a visual camera system is provided near the corner of the upper surface of the base plate (21), a left positioning block (2) is mounted above the base plate (21) and near one side of the wafer center positioning fixture (4), and a right positioning block (5) is mounted above the base plate (21) and near the other side of the wafer center positioning fixture (4); The visual photography system includes a translation axis motion guide rail slider (18), the translation axis motion guide rail slider (18) is slidably mounted on the upper end surface of the base plate (21), one end of the translation axis motion guide rail slider (18) is fixedly connected to a Z-axis mounting member (16), and a Z-axis motion guide rail slider (15) is mounted on the outer side wall of the Z-axis mounting member (16) near the upper end; A translation axis motor (17) is installed on the upper surface of the bottom plate (21) near one end of the translation axis motion guide rail slider (18), and the output end of the translation axis motor (17) is connected to the translation axis motion guide rail slider (18); The outer wall of the Z-axis motion guide rail slider (15) is fixedly connected to a mounting plate (7), the outer wall of the mounting plate (7) is fixedly mounted with a camera (19), the bottom surface of the camera (19) is fixedly connected with a lens (10), and the outer wall of the Z-axis mounting member (16) and located below the Z-axis motion guide rail slider (15) is fixedly mounted with a light source mounting adjustment member (13); A Z-axis motor (12) is fixedly mounted on the outer wall of the Z-axis mounting member (16) and located below the light source mounting adjustment member (13); and a light source (11) is mounted on the outer wall of the Z-axis mounting member (16) and located directly below the lens (10); A left servo translation arm (3) is fixedly mounted on one side of the left positioning block (2), and a right servo translation arm (6) is mounted on one side of the right positioning block (5); A spindle motor (25) is installed near the middle of the upper surface of the base plate (21), an exhaust box (24) is installed near one side of the upper surface of the base plate (21) near the spindle motor (25), and a liquid extractor (27) is fixedly installed near one side of the upper surface of the base plate (21); The outer side wall of the translation base plate (26) is installed with a left servo translation mechanism (8) and a right servo translation structure (9); a nozzle wetting and waste discharge assembly (22) is fixedly installed below the right servo translation arm (6); a front side washing and waste discharge box assembly (23) is fixedly installed below the left servo translation arm (3); and a cavity leakage connection plate (28) is fixedly connected to the bottom surface of the base plate (21).

2. The method for centering a wafer in a cavity according to claim 1, wherein: The specific steps of the method are: Step 1: Place the wafer on the left positioning block (2) and the right positioning block (5), the left servo translation mechanism (8) drives the left positioning block (2) on the left servo translation arm (3) to move to the right, and the right servo translation mechanism (9) drives the right positioning block (5) on the right servo translation arm (6) to move to the left, thereby preliminarily clamping and fixing the wafer; Step 2: Use the translation axis motor (17) to drive the Z-axis mounting part (16) to translate on the translation axis motion guide slider (18) toward the wafer, then use the camera (19) to take a picture of the wafer edge to find the center position of the wafer, and calculate the position error between the two by comparing it with the center position of the wafer carrier (1). The error value is sent to the vision software, and the vision software calculates the required translation amount of the wafer in the X direction and the Y direction; Step 3: The visual software drives the left servo translation mechanism (8) and the right servo translation mechanism (9) to move the wafer in the X and Y directions; Step 4: After the translation is completed, the visual camera system takes another photo of the edge of the wafer to find the center position of the wafer after translation, and calculates the error with the center of the wafer carrier (1). If the error is within the error range allowed for wafer processing, the center positioning of the wafer in the cavity is completed and wafer processing begins.

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